Final  Technical  Progress  Report
           Report No. 6
 24 June through  23  December 1972
      GEOMET, Incorporated
Office  of  Experimental Development
     2814-A Metropolitan  Place
     Pomona,  California  91767
  GEOMET, Incorporated

           50 MONROE STREET
       ROCKVILLE, MARYLAND 20850
              301/762-5820

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         Contract  No. 68-02-0578
    Development of Instrumentation  for
     Quantitative  Collection of Total
 Atmospheric Mercury from Ambient  Air
     Final Technical Progress  Report
              Report No. 6
    24 June through 23  December 1972
          GEOMET,  Incorporated
   Office of Experimental  Development
        2814-A  Metropolitan  Place
        Pomona,  California  91767
  Authors:  D. J.  Sibbett and R. C. Wade
      Publication Date: August    1973
Prepared for the Environmental Protection
     Agency, Research Triangle Park
          North Carolina  27711
       GEOMET  Report No.  LF-215

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                      TABLE OF CONTENTS
1. 0  INTRODUCTION                                         1- 1

2.0  PROGRAM ACCOMPLISHMENTS                         2-1

     2. 1       Technical Approach                            2-1
     2.2       Phased Fulfillment of Program  Goals           2-5
     2.3       High-Volume Air Sampler  Selection            2-12
     2.3. 1    Hi-Vol Sampler  Through-put Studies            2-15
     2.4       Mercury  Challenge Sources                    2-16
     2.4. 1    Particulate Mercury Challenge Sources         2-16
     2.4.2    Elemental Mercury Vapor Source               2-17
     2.4.3    Organic Mercury Challenge Sources            2-19
     2.4.4    Ambient  Air  Challenges                        2-22
     2.5       Air  Train Challenge  Apparatus                 2-22
     2. 5. 1    GEOMET Model 103  -  Mercury  Air Monitor    2-29
     2. 5. 1. 1  General Description                            2-29
     2. 5. 1. 2  Improvements to Model 103                    2-32
     2.5.1.3  Details of Changed Features                   2-34
     2.6       Mercury  Absorbent Development               2-39
     2.6. 1    Selection of Adsorbents                        2-39
     2.6.2    Particulate Mercury Collector                 2-44
     2.6.3    Elemental Mercury Adsorbents                 2-44
     2.6.3.1  Commercially Available Silver-Treated
                Adsorbents                                   2-51
     2.6.4    Organic Mercury Absorbents                   2-53
     2. 7       Prototype Collection System                   2-54
     2.7. 1    General                                       2-54
     2. 7. 2    Hi-Vol Collection Plenum                      2-55
     2.7.3    Collection Canister Design                      2-67
     2. 7.4    Recovery Analysis System                      2-73
     2.7. 5    Demonstration to EPA Program Monitor        2-73
     2.8       Recovery Analysis Procedures                 2-82
     2.8. 1    Recovery System Description                   2-82
     2.8.2    Analysis  of Particulate Mercury Samples       2-85
     2.8. 3    Analysis  of Adsorbent  Pellets                  2-86
     2.8.4    Analysis  of Charcoal Absorbent                 2-90
     2.8.5    Other Analysis Methods                        2-91
     2.8.6    Additional Analysis Equipment                 2-92
     2.9       Prototype System Test Data                    2-96
     2.9. 1    Collection Efficiency Tests                     2-96
     2. 9. 2    Ambient  Air  Monitoring for Elemental
                Mercury                                     2-106
                                11

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                  TABLE OF  CONTENTS  (Con't.)


                                                       Page
3.0  CONCLUSIONS, RECOMMENDATIONS AND
     COMMERCIAL PRICE ESTIMATES                     3-1

     3. 1      Summary                                   3-1
     3.2      Recommendations                            3-3
     3.3      Commercial Price Estimates                 3-5

4.0  EQUIPMENT DEVELOPMENT  TABULATION            4-1
                             iii

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                           FIGURES
2- 1   Assembled Sampler  and Shelter                        2-13
2- 2   Commercial Hi-Vol  Samplers                          2-14
2- 3   Elemental Mercury Vapor Source                      2-18
2- 4   METRONICS  DYNACAL Permeation Tubes              2-20
2- 5   GEOMET  Model 103  Instrument Calibration             2-23
2- 6   Mercury in Air Sampling Train                        2-25
2- 7   Canister Holder and  Sampling Plenum for
          Hi-Vol Sampler                                     2-26
2- 8   Collection Canister/Hi-Vol  Sampler Interface
          Configuration                                       2-27
2- 9   Final Collection Plenum Configuration                  2-28
2- 10   Complete  Prototype  Instrumentation Assembled
          with  Test  Apparatus                                2-30
2-11   Function Diagram, Model 103                          2-31
2-12   Model 103 with Catalytic  Converter                    2-31
2-13   Electrical Wiring Schematic, Model 103                2-33
2- 14   Recent Improvements in Lamp Controls and
          Adjustments                                        2-35
2-15   Recent Improvements in Model 103 Grid Control
          Circuitry                                           2-35
2-16   Twenty-Four Hour Collection Efficiency Tests,
          Silver on Alumina Pellets                          2-48
2-17   Hi-Vol Collection Plenum Installed in Place            2-56
2-18   Collection Plenum Canister  Assembled Onto
          Hi-Vol Sampler                                     2-57
2-19   Hi-Vol Collection Plenum Details                      2-58
2-20   Plenum Tube                                          2-59
2-21   Flange Ring                                           2-60
2-22   Thread  Ring  Modification                              2-61
2-23   Plenum Tube Weldment                                2-62
2-24   Orifice Housing                                       2-63
2-25   Retaining  Ring                                        2-64
2-26   Pressure  Tube                                        2-65
2-27   Air Bypass Control Ring                               2-66
2-28   Collection Canister /Hi-Vol  Sampler
          Prototype  Interface Configuration                    2-69
2-29   Prototype Multiple-Use Collection  Canisters            2-70
2-30   Canister Body                                         2-71
2-31   Canister Screen Closure Details                        2-72
2-32   Recovery  Crucible Furnace  Details                    2-75
2-33   Furnace  Cover                                        2-76
2-34   Crucible Cover                                       2-77
2-35   Outlet Tube                                           2-78
2-36   Collect  Tube                                          2-79
2-37   Crucible Details                                       2-80
2-38   Disc                                                  2-81
                                IV

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                          FIGURES (Con't.)
2-39   Mercury Challenge Collection Method                  2-83
2-40   Analytical Method                                     2-84
2-41   Conceptual Mercury Recovery  Resistance Furnace      2-88
2-42   GEOMET  Model 103 Calibration Data                  2-116
2-43   Calibration of Perkin-Elmer Model 303
         Atomic Adsorption Spectrophotometer                2-117

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                            TABLES
2-1    Phase  Program Goals                                 2-7
2-2    Prototype System  Test Data                           2-100
2-3    Analysis in Ambient Air  Test,  GEOMET Model 103    2-108
2-4    Atmospheric Test, GEOMET  Model 103  Data           2-114
2-5    Ambient Air Test, Canister Method - Analysis of
          Silver/Alumina Adsorbent                           2-119
4-1    Equipment Tabulation Sheet                            4-2
                                 VI

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   Section 1. 0




INTRODUCTION

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                              Section 1. 0


                           INTRODUCTION




          GEOMET, Incorporated submits the draft of the Final


Report under Contract  68-02-0578 in accordance with the Reports  of


Work  Requirements as  stipulated by the  contract.   This report pro-


vides  a  description  of the effort  expended over  the  period of 24 June


through  23  December 1972.


          The objective of the program for  Development of Instrumen-


tation  for Quantitative  Collection  of  Total  Atmospheric Mercury from


Ambient Air was to design,  develop and  fabricate a prototype  collec-


tion device for the quantitation of mercury in air in the three  major


forms:  (1) inorganic and organometallic  particulates, (2)  inorganic


and organometallic vapors,  and  (3)  elemental mercury at  levels up to

                                             3
a threshold limit value of  100  micrograms/M .  The collection device(s)


and attendant processing techniques  are compatible for utilization in


or  with  Hi-Vol samplers of  the  National  Air Survey Network for air


sampling in the  field.   Design of the collection  devices is oriented


to obtain quantitative mercury retention,  to  give convenient packaging,


storage  and shipping, and to give ease of analysis at centrally


located laboratories after  use.


          The  scope of  the contract  effort included the design,  fab-


rication  and testing  of prototype collection devices,  adaptation  of


those devices to Hi-Vol samplers, provision  of techniques and  pro-


cessing  equipment for analysis of the collected mercury forms, full
                                1-1

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system quantitative testing,  and delivery to EPA  of the set of



prototype instrumentation following a demonstration of the effective-




ness of the system.  The overall aim  of the program was to provide



qualified prototype  instrumentation capable  of being put into the field



on an  economical large-number basis.
                                 1-2

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         Section Z. 0




PROGRAM ACCOMPLISHMENTS

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                             Section 2. 0




                   PROGRAM ACCOMPLISHMENTS








           The effort  expended under this program covered the




 development of a Prototype  form of the mercury collection device.




 The collection method allows the total  and quantitative collection and




 separation of the three forms of mercury - (1)  particulate,  (2)  ele-




 mental and (3)  inorganic  and organomercury vapors.   These  individ-




 ual samples may be  easily packaged and transported  back to some




 centralized laboratory for analysis.   The analysis measures  the




 mercury  content in each  collected solid phase,  corresponding to the




 forms indicated  above and thus provides total  mercury values regard-




 less of the mercurial forms present in  the sampled ambient air.






 2.1  TECHNICAL APPROACH




           The  technical approach for  the Development of Instrumenta-




 tion for Quantitative  Collection  of Atmospheric Mercury from Ambient




 Air was designed to meet all the requirements  stipulated  by the  EPA




 in Contract No.  68-02-0578.  The program was carefully  structured



 to be compatible with the phases contained in  the  Contract Scope of



 Work (Reference Section 2. 2  below).  In  addition,  the program was



 oriented to provide the necessary technical data from  practical




 testing  of  hardware developed under the contract.




          Specific areas of  development  effort  were 1) the minimal




modifications  to  a  standard Hi-Volume  air sampler while incorpora-




ting the new instrumentation, 2) definition of  collection canister  con-
                                2-1

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figuration and selection of absorbents  for  all forms of mercury, and




3) utilization,  as a baseline configuration,  of existing  chemical  and




electromechanical  devices for  analysis of  collected mercury  samples.




A stepwise  approach to the solution of these problems was created  in




order  to optimize  the  accomplishments during this short duration pro-




gram.




Hi-Volume  Sampler Modifications




          In accordance with the  contract  Scope of Work,  prelimin-




ary design  concepts  relating to the collection system evolved around




the insertion  of  collection canisters into the body of a typical Hi-Vol




sampler.   This concept precluded any physical change to the  sampler




itself,  but did increase the sampler height.  It is  expected that this




added  canister plenum, incorporating threaded ring fittings,  will be




adaptable to all commercially  available Hi-Vol  samplers  being mar-




keted in the continental United States.  The only remaining assembly




criteria is  the varied  construction  details  of shelters  in which the




Hi-Vol samplers are  operated.  GEOMET chose a UNICO 550 Turbine-




Jet High-Volume Air  Sampler  (marketed by  the  Environmental Science



Division,  Bendix Corporation)  for use on this  program.   This particu-



lar sampler is housed in a rather  inexpensive  plywood shelter.   Since




the sampler is supported in place by the upper  edge of the incoming




air funnel duct,  the Hi-Vol and collection  plenum now extends below




the sides of the  shelter.   This in no way  affects the operation of the




sampler,  but does allow  the Hi-Vol air through-put gage to be some-




what exposed to  the open air and brings the exhaust port  closer to the
                                 2-2

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ground.   GEOMET also owns  a High-Volume sampler marketed by




the PRECISION Scientific Company.   This Hi-Vol is supported  by a




ring around the  blower motor  housing,  rather than by the air inlet




ducting.   When installed in the  supplied aluminum  shelter, the Hi-Vol




and plenum  system protrudes  above  the shelter  at  the top prohibiting




positioning  of the hinged roof-cover.  It is,  therefore,  concluded that




while the simple  utilization of the collection plenum obviates any mod-




ification to the  Hi-Vol  sampler, some  slight modifications may have




to be made  on specific Hi-Vol sampler shelters currently in  use in




the National Air Sampling  Network (NASN).  Any modifications would




consist of increased side protection  and be dependent on  the  type  of



shelters in use.




          Details of the collection sample  plenum for the Hi-Vol




samples are included in Section 2. 3,  below.




Collection Canister Configuration and Absorbents




          In the  proposal for  this  program,  GEOMET  submitted con-




ceptual designs  for the Prototype instrumentation.  As  a  part of the




total system, the idea of using stacked "canisters" for positioning




and support  of the mercury absorbents  with the Hi-Vol  was established.




During the program,  various  developmental parameters were exploited




and the Prototype design evolved as  a result of  testing several con-




figurations.  Several limiting factors became readily apparent.   The




maximum height and diameter  of two or more collection  canisters was



determined  by  Hi-Vol  sample air through-put,  necessary  adsorbent




volume as determined by the  collection efficiency of the test  absor-
                                 2-3

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bents, and the wide range over which quantitative  mercury collection



must be made.   The  final configuration  of the  canisters was pre-



dicated on results of  testing to explore these limiting factors.   The



rationale  for  canister  size, while  tied directly  and unequivocally to



absorbent bed size, was to provide space for enough absorbent  (in



the elemental mercury collection canister) to cover mercury levels


                                             3                   3
spanning five (5)  decades, i.e.  from  1 ng/M to 100,000  zig/M  of



mercury.   Also,  the  constraint of final  analysis of the sample  by



commercially available instruments was  superimposed onto the canis-



ter design calculations,  and subsequent testing  was utilized  to ascer-



tain the minimum canister  sizes which would provide enough sample



of any range  of collected mercury for meaningful  analysis.   Of



lesser importance,  was  the actual canister  configuration.   Here items



such  as materials of  construction, handling  and packaging were investi-



gated.  The  collection canister design for the Prototype system is a



result of  the  investigation of these factors.   Further details  of the



current design are found in Section 2.6.3 and 2.6.4 of  this report.



          Absorbent development was  based  on the premise that both



EPA  and  GEOMET wanted several non-sole  source commercial sup-



pliers of  absorbent for the Prototype  system.   GEOMET  examined



several potential  sources of commercial  collection media and pur-



chased batch  lots of treated aluminas and charcoals  for the  collec-



tion of elemental and  organic mercury.   Finally,  GEOMET set  out  to



manufacture  batch lots of treated alumina for elemental mercury col-



lection.   None of the tested, commercially available absorbents  were
                                 2-4

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 comparable  in performance to the GEOMET product.   Therefore, all




 elemental mercury collection made during the final test periods of




 the program were made with the GEOMET prepared  absorbent.




 Developmental details of this effort are found below in subsections



 of 2.6.




 Analysis  of  Collected Mercury Forms




          GEOMET utilized, as a baseline system,  the wet chemistry



 method for determination of mercury as described in  the Federal




 Register,  Volume 36,  No.  234  - Tuesday,  December  7, 1971.   GEOMET




 did,  however, institute  unique pre-processing steps as well as add other




 types of instrumentation between the liquid impinger system and the




 Atomic Absorption Spectrophotometer (AAS).   A  special technique was




 also developed for the analysis  of particulate mercury found on the Hi-




 Vol filter.   The analysis  procedures  finally  developed, while  still  in




 the prototype stage,  fully satisfied the  needs of  the program as speci-



 fied  in the Scope of  Work and appear to offer an accurate and precise




 method of rapid  testing of samples.   Specific procedural  steps are



 found in  Section  2. 7  below.






 2.2 PHASED FULFILLMENT OF  PROGRAM GOALS




          In  Exhibit  "A" of  the  contract,  Scope of Work,  the  Environ-




 mental Protection Agency provided a  program effort outline divided




 into five (5)  Phases.  Inasmuch  as this phased  effort  has considerable



 overlap in tasks  between phases,  GEOMET  reordered  some of the




tasks for  a more chronological approach to the development of the
                                 2-5

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instrumentation.   In order to clearly demonstrate  the  GEOMET res-



ponse to the Scope  of Work, the following table is provided which



indicates  Phase task and the corresponding GEOMET  development.




Reference is also provided to Sections of this report wherein  addi-



tional data may be  found.
                                2-6

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                                      Table 2-1  Phase Program Goals
 Scope of Work;

       Phase I
                                                                         GEOMET  Response
to
The  Contractor shall design,  fabricate,  and
evaluate a prototype device for the quantitative
collection of airborne mercury and its  com-
pounds  (inorganic salts  and organometallic
vapors) from the ambient  air.   The device
shall have the following  performance charac-
teristics:

A.    The prototype  device shall be  constructed
      for ease of handling  in  field operations
      and shall be simple  and compact  in  struc-
      ture to facilitate low cost shipment by mail
      to central  laboratories following sample
      collection.

B.    It is desired that  the collection device be
      used with the Hi-Vol samplers  of  the
      National  Air Survey  Network as an attach-
      ment to  their present collection system.

C.    Construction materials  shall be economi-
      cal,  to  allow  for  eventual  production  of
      large numbers of  the collectors for  nation-
      wide surveys.
       D.    The materials of construction shall have
            a low mercury background and be  readily
            cleaned of any mercury collected.
The collection canister design  is  simple, inex-
pensive and compact.   The  plastic  cylinders
may be reloaded in the field or mailed to lab-
oratories in commercially available  containers.
(Section  2.6,  2.7, and 3.0)
                                                            The collection plenum inserts into  the Hi-Vol
                                                            sampler  without modifications to the Hi-Vol or
                                                            use of special tools.   (Section 2. 7. 2)
Initial collection plenum  construction is of alum-
inum.   Prototype canisters are  of  PVC plastic.
It is  conceivable  that  ultimately all parts could
be fabricated from low cost plastic materials.
(Sections 2. 7. 2 and 3. 3)

Current materials are free from mercury, and
it is  not apparent that these materials  are absorb-
ing mercury during  sample testing.  (Section  2. 7)

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                                Table 2-1  Phase Program Goals (Con't. )
Phase  I (Con't. )

     E.    The  collection device shall be capable of
           retaining  the  collected mercury  in  all its
           forms in  a stable  state for several -weeks
           and to quantitatively release the mercury
           for analysis.
           The collection device shall be capable of
           quantitatively collecting all forms  of  mer-
           cury from the ambient  air  at flow  rates
           common for the Hi-Vol sampler (20  CFM
           or  better).   Its  capacity for retention of
           mercury and its compounds should be for
           all  mercury present in a 24-hour  consecu-
           tive sampling period.  This requires  the
           capability of handling mercury concentra-
           tion ranges from the natural background
           levels  of  a  few nanograms  per  cubic  meter
           to the  threshold limit value of 100  micro-
           grams per  cubic meter.

           The collection device may  consist  of  sev-
           eral stages or  compartments with each
           specific for  a particular form of mercury
           found in the ambient air.    The three forms
           of mercury to be collected separately are
           elemental mercury,  inorganic and organo-
           metallic mercury in particulate  form, and
           inorganic and organometallic mercury
           vapors.
IS)
i
00
              GEOMET Response  (Con't.)

Absorbents clearly absorb the levels of mercury
stipulated  by  the  Contract.   Collection efficiency
runs  show that  some slight difficulty remains in
uniform recovery  of all absorbed  mercury vapor.
Careful packaging  will hold samples  in  stable
state  for  several weeks.   (Section 2. 8. 3)

The collector separates particulate,  elemental
and combined mercury  (vapors)  onto a glass
fiber  filter,  a silver /alumina adsorbent and acti-
vated charcoal,  respectively.   Sampling  rates  of
20  CFM or better have been  utilized.   Several
long duration sample runs at Hi-Vol through-put
of  220 CFM were made  during the course of  the
program.  Challenges varied from 4. 5 x 10  -
/ซg/M3  (elemental) to 118 yซg/M3 (organic).  These
combined mercury runs are  reported in Section 2. 9.
                                                           The Prototype system utilizes a  standard Hi-Vol
                                                           fiberglass filter for inorganic and organometallic
                                                           particulate forms,  a  canister stage for  elemental
                                                           mercury and for inorganic and organometallic
                                                           vapors.   (Sections  2. 6 and 2. 7)

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                                 Table 2-1  Phase  Program Goals  (Con't. )
 Phase I (Con't. )

      H.    The collection device shall  be able to  sep-
            arate  for independent analysis the  three
            major  forms  of mercury  (elemental, parti-
            culate,  organic vapors).

      I.     A removal procedure for  the  collected  mer-
            cury shall be developed so  that the mercury
            can be analyzed by readily  available analy-
            tical instruments,  both inexpensive and soph-
            isticated.

      J.    A delineation  of the  types of  instruments
            that can  be used for these analyses and
N           proof  of  their  capabilities shall be pre-
            pared and  submitted to the Project Officer.
              GEOMET Response  (Con't. )

Collection  stages (previous  page) hold  each form
of mercury in a separate  state for independent
analysis.   (Sections 2. 6,  2. 7 and  2. 9)
GEOMET has  developed unique apparatus  and/or
methods for recovery  analysis  of  collected mer-
cury.  See  Section  2. 9.
Instruments,  by type,  for similar processing
are noted in Section 2. 8. 6.
 Phase II
      The  fabricated  collection device shall  be checked
      to establish  its efficiency for collection  of  air-
      borne mercury and its  compounds.   Known mer-
      cury standards in  several chemical forms (ele-
      mental,  inorganic,  organometallic)  shall  be
      used to determine  their collection characteris-
      tics.   Modifications should be made to optimize
      the collection  efficiency of  each species.  Sev-
      eral environmental factors  shall be checked for
      their influence  on  the collection efficiency of the
      device.   These are  climate factors such as tem-
      perature in the temperate range, moisture,  dust
      load, and winds.   Other fact orb like  gaseous pol-
      lutants  (H2S,  SO2,  NOx,  phenols,  hydrocarbons)
      shall be checked for their  effect on the  collection
      efficiency for mercury.
The Prototype system was  effectively challenged
by  varied amounts of elemental vapors,  organic
mercury, and solid particulate mercuric com-
pounds.   Collection efficiency runs were carried
out and reported  on a monthly  program basis.
Contaminant gases were superimposed  over the
combined mercury form challenges.   Limited
ambient  air  challenges  were  carried out with the
total  system.  (Section 2. 9-all subsections. )

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                                Table  2-1   Phase Program Goals (Con't. )
Phase  III
      A transfer step to remove the collected  mer-
      cury from the  collector to an appropriate anal-
      ytical instrument  is envisioned.  The step could
      require the development of a  handling  system
      for  transfer of the mercury vapor.   If such a
      system is developed, it shall  be  tested for quanti-
      tative transfer  and clean-up to the previous  back-
      ground levels for  mercury.
                  GEOMET Response

GEOMET utilized a  modified Hatch  and Ott
procedure for processing the elemental and
organic  samples through the analysis  pro-
cedure.   Special handling and processing  com-
ponents  were fabricated to aid  in  the  analysis
of the adsorbents.  (Section 2.8).
Phase  IV
I
H—
o
      Detailed  scientific data shall be furnished to
      support  all claims  on the efficiency of mercury
      collection.   Similar data shall document the
      effect of  atmospheric variables and  gaseous pol-
      lutants on the collection  efficiency.   Prototypes
      of the developed  collection device and any  trans-
      fer system shall be furnished.

      A tabulation of the specifications of all  equip-
      ment developed under this  contract  shall be
      submitted to the  Project  Officer with the final
      report on this project.   If a transfer or sample
      processing step is  necessary  before the mercury
      sample can be analyzed,  a written procedure for
      this operation shall  be furnished with the final
      report.
Comprehensive testing of the Prototype system
was carried out,  including  several long dura-
tion (^24 hours)  runs.   The  results  of these
tests are discussed  and  tabularized in the  sub-
sections under  Section 2. 9.
The tabulated  equipment list  is presented in
Section 4. 0.   Procedures  for sample analysis
are* discussed  in Section 2. 7. 2.

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                                Table 2-1  Phase Program  Goals (Con't. )

Phase  V                                                                    GEOMET Response

     At the  completion of  the  effort prescribed  here-    GEOMET,  with permission of  EPA,  demon-
     inabove,  the  Contractor shall  conduct a demon-     strated the Prototype system and  procedures
     stration of the  operation  of the collection  device    to the Program Monitor at the  GEOMET lab-
     developed under this  contract  before  the cogni-     oratory in Pomona,  California. (Section 2.7.5)
     zant  Project  Officer  at the National Environ-
     mental Research Center,  Research Triangle
     Park, North  Carolina  27711.

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2.3  HIGH-VOLUME AIR SAMPLER  SELECTION
          GEOMET  purchased and has operated  a Unico 550  Turbine-
Jet High-Volume Air Sampler (Environmental Science Division,  Bendix
Corporation)  throughout this program.   The  Unico was  chosen due to
the simplicity of design of the sampler  and of the sampler  shelter.
The sampler is hung in the wooden  shelter  and supported by the
lower edge of the inlet ducting adaptor which contains the particulate
filter.   A typical sampler  of this configuration  is  shown in  Figure 2-1.
The originally  proposed concept was to  place a  collection  plenum  be-
tween the incoming  air duct, and the sampler blower motor  casing.
The Unico 550  lends itself quite  suitably to this arrangement.   The
plenum  elongated the blower/ducting dimension,  but does not affect the
sampler  operation nor  cause any modification to the  sampler  shelter.
The addition  of  the  plenum to the Unico  550 is shown, in a conceptual
sketch,  in Figure 2-2A.
          GEOMET  also owns a Precision Scientific Hi-Vol  sampler,
which is offered with an optional aluminum  shelter.  While the  shelter
for the  Precision  sampler is well built and durable,  the sampler/
shelter  combination  requires  modification to  add the  GEOMET collec-
tion plenum.  This sampler is held  in place by a  notched  shelf built
into the  shelter.   The Precision  Hi-Vol contains a cast  ring  which is
an integral part of the  sampler blower  motor housing.   The  ring  rests
on the shelf and supports the sampler within the shelter (Figure 2-2B).
With  this particular  unit,  the collection  plenum  cannot be  inserted into
the sampler system  without  either obviating the  use of the shelter roof,
or lowering the  shelter sampler  support shelf to allow clearance for
the Prototype system.
                                2-12

-------
                       ExplodeJ vltw of typlc.l high-vclmr.* ซ!r Mnplir parti.
Figure 2-1.    Assembled Sampler  and Shelter.
                                    2-13

-------
                            Sampler
                            Support
                            Shelf
A.   Assembled Sampler and
     Collection Plenum in
     Wood Weather Shelter
                                GEOMET
                                Collection
                                Plenum
                                            B.   Precision  Scientific
                                                High-Volume Sampler
                                                and  Aluminum Shelter
                              Figure  2-2

                 Commercial Hi-Vol Sampler

                                2-14

-------
          Two points are evident as a  result of this discussion:




1} the Unico 550  sampler and  shelter were well chosen for  this pro-




gram,  and  2) thought should be given  to  the  varied configurations  of




sampler shelters already in the field.  It is  assumed that some




standard will be  set on High-Volume sampler configuration,  or that




the simple  modifications  necessary to accept this Prototype instru-




mentation will be allowed.






2. 3.1   Hi-Vol Sampler  Air Through-put Studies




          The first work  done with the Unico 550 Hi-Vol  sampler



was to run preliminary studies on air through-put  of collection




materials and collection canister configurations.




          Various mesh sizes  of  charcoal and alumina  were tested in




a  cylindrical tube mounted  in the annular  throat of the Hi-Vol  filter




adapter ducting.   Barnebey-Cheney 6-10 mesh activated charcoal was




tested, as well as the following alumina material - Harshaw 0.125




inch diameter  pellets,  Alcoa 4-8 mesh and Alcoa 8-14  mesh granules.




It was  determined that  up to 3.75 inch bed depths  of these materials



could  be loaded in a 3. 0  inch  average diameter  tubular canister,  and




a  nominal  value  of  20  CFM could be easily pulled  through the  Hi-Vol




sampler.   Later, up to seven inches of alumina  (0.125" pellets) were




utilized with the  Hi-Vol,  including a fiberglass  particulate filter,  and




a  nominal  value  of  20  CFM through  the Hi-Vol was maintained.




          Through-put  studies were also made of a prototype canister



made of perforated  stainless steel.   A 400 gram batch of alumina




pellets  ( -%^3. 50 inches  deep in a 3.1 inch diameter canister) which
                                2-15

-------
had been tested in the Hi-Vol  at  20  CFM, gave  35 CFM  through-put




when transferred to the prototype perforated canister.   These  canis-




ters,  containing eight 0. 062 holes per linear inch (64 per inch ) were




considered for  final canister configurations wherein collection media




density or  shape required large volumes of  the  collection material




and low residence time of the through-put sample air stream.   These




early Hi-Vol tests  outlined the magnitude of the amounts of adsor-




bents which could be used to collect mercurial vapors.   The ultimate




sizing of the canister beds is  discussed in  Sections  2.6,  3.3 and  4.0.






2.4  MERCURY CHALLENGE  SOURCES




          In order to evaluate the interim design concepts and com-




ponents prior to the design of  the Prototype  system,  methods of pro-




viding accurate amounts of the three forms  of mercury were neces-




sary.   These methods and/or apparatus  required capability of supplying




mercury  challenges to the collection system with known  mercury con-




centrations and minimum loss.   The minimization of loss was a very




important aspect of the total collection efficiency  of the Prototype




system.   A review of the  challenge methods is presented in the follow-



ing sections.






2. 4.1  Particulate Mercury Challenge Sources




          GEOMET utilized ultra-fine mesh mercuric oxide (HgO)  and




mercuric sulfide  (HgS) to challenge the collection  efficiency and par-




ticle retention of the  standard  fiberglass Hi-Vol  Sampler filter.   All




runs on this program were made using the  Reeve  Angel  934-A12




(8" x 10") standard Hi-Vol filters.  It  was discovered early in  the






                                 2-16

-------
program that in order to provide even distribution  of the challenge




material over  the filter  area,  the mercuric compounds must be




mixed with some inert carrier.   This was  especially true at low




challenge levels wherein less than 1.0  /*gm of material was to be




used.   To prevent as much loss  of the challenge sample as possible,




the weighed  aliquots of HgO  or HgS were placed into 45 gram




batches of Cab-O-Sil, an inert  fumed silica.   This mixture  was then




fed into the  Hi-Vol sampler  air stream and onto the filter.   This



method was  extremely successful for the  application of particulate



challenges to the Prototype instrumentation  system.






2.4.2  Elemental Mercury Vapor Source




          Four separate  source models were constructed in  the




attempts to assemble a device for challenging prototype collection




canisters with elemental mercury,  Early attempts were made to




devise  a method for determination of mercury vapor emissions



through weight  loss measurements.  Considerations of  the very




small amounts  of mercury to be  measured  caused the  abandonment




of this procedure.  The  ultimate  method  devised,  which has been



completely successful, utilized air passage  over heated  liquid mer-




cury  under controlled conditions.   This apparatus is depicted in




Figure 2-3.



          In  operation, air is pumped through  the sealed  vapor




source system  and  passes over a small pool of liquid  mercury.




Heating tape is used to heat the mercury held in the U-tube increas-



ing the mercury vapor pressure for high  challenge  levels.   Voltages
                                 2-17

-------
Vapor  to Hi-Vol
for Challenges
                                                Reference Temp.
                                                 Thermometer
                                                  Pyrex U-Tube
                                                 Containing Mercury)
                                                        0-12 1/min.
                                                        Flowmeter
                                                        Control Valve
                                                         Activated Charcoal
                                                         Air Filter
                                              Air Inlet
                Figure 2-3  Elemental Mercury Vapor Source
                                     2-18

-------
from 0-60 VAC yield challenges of from 0.3 to >200yug/M   (at




temperatures ranging from x^ZO C to ,*xl20 C).   All data was taken




with air flow through the U-tube at 5 liters/minute, but both air flow




and  temperature can be  varied for  a wide range of values.   Testing




proved  the  success of  this  method in providing elemental mercury




vapor challenges over the  complete spectrum of mercury levels re-




quired for quantitative testing  under the  scope of this  program.






2. 4. 3   Organic Mercury Challenge  Sources




          Several challenge methods were evaluated for  organic mer-




cury input sources  during  this  program.   Early attempts using  com-




mercial mercury sources were unsuccessful.   For example,  a  diethyl




mercury  Dynacal permeation tube was acquired from Metronics  Asso-




ciates.   It was Certified to permeate at  a  rate  of  264 -5% ng/minute




at 40ฐC.   This special-order  device was utilized in a Metronics heat




exchanger and tube holder, as  depicted in Figure 2-4.  Challenge




runs were attempted utilizing  a 200 gm.  collection canister filled




with sulfur treated  (13%) activated charcoal.   Permeation tube  chal-




lenges at 40ฐC were monitored with a GEOMET Module 109 Catalytic




Converter in conjunction with  the Model 103 M. A. M.  It was rapidly



apparent  that the permeation tube was releasing elemental  mercury




vapor into the tests rather than diethyl mercury, exclusively.  Appar-




ently,  the diethyl mercury  in  the permeation tube was partially hydro-



lyzed or  decomposed.  For the purpose of testing adsorption  on the




sulfur treated charcoal,  this mixed source  was not satisfactory.  No




further testing was attempted  with this prototype permeation  tube.
                                 2-19

-------
                                 Figure 2-4
                                               Technical Bulletin  No.  7-70
                                               DYNACAL* PERMEATION TUBES
       APPLICATION NOTE  ON THE TESTING AND CALIBRATING OF AIR ANALYZERS
 Testing

    An  air analyzer can be quickly tested  to  see  if it  is "about right" by
 placing a DYNACAL*  permeation tube  into  the  analyzer's  inlet air stream.
 One  satisfactory test method is to  put the DYNACAL*  tube into a cylinder
 such as a 20-cm glass drying tube and connect  the lower end of the drying
 tube to the analyzer inlet. Clean and empty  gas  absorbtion tubes (plastic)
 work equally well.   Temperature is  obtained  from a thermometer placed near
 the  inlet.  Concentration is estimated using the DYNACAL*  standard rates
 for  the particular temperature and  tube  length.


 Calibrating

    A DYNACAL* permeation  tube and the Metronics  specially constructed 2-
 section glass apparatus can be used as shown below to provide a gas stream
 of known concentration for dynamic  calibration.

                                                 ntrt Connecting Tubing
                                                 (thortatpoMibl*
                      rf_   H  /H         /
                 Air
                                      , InirHJMd Cut,
                                     For Eoty ACCMI (I)
                                   Thซrmomซtซ(4)
                                          DYNACAL RMHONM
                                          Tutt On Owmhwm S*{2)
                high vokm. flow
                UM fl COl I 0* COppflr
                tubing upHnomXI)
                                        -PnroMGfcmnoMl)
                          A SIMPLE CALIBRATIOH APPARATUS
Parts List
1.  Heat  exchanger and tube holder with with  glass  beads available from
    Metronics.   Model 4-15 holds 4 ea. 15-cm  tube
                 Model 4-30 holds 4 ea. 30-cm  tubes
2.  DYNACAL* tubes  available from Metronics.
    HOW TO ORDER.
                                                Please see other side for
3.  Inlet filter  similiar to GCA Chemical Cartridge and  end-of-line holder
    available  from Mine Safety Appliance, 201 N. Braddock Ave.,  Pittsburgh,
    PA 15208 is adequate for most purposes.  Cylinders of zero-air or nitro-
    gen are recommended where background contamination is significant.

4.  Thermometer,  high grade laboratory type of suitable  range and gradua-
    tion, is available from most laboratory supply companies.
5.  Constant temperature bath can range from tap water bath (about 17ฐC in
    our local  system) to baths complete with precision temperature control-
    lers such  as  those sold by Cole-Parmer, 7425 N. Oak  Park Ave., Chicago,
    111. 60648.
?ON|GS  ASSOCIATES,  INC.  aaoi PO*TซR DRIVE • ปTANFOIปO INDUSTRIAL MUK • PALO AL.TO. cซuronปiiป
                                     2-20

-------
          Diluted die thy 1 mercury  in  CC1. was  also  briefly utilized




to assess the collection  on sulfur-treated  charcoal.   However,  again




decomposition or hydrolysis appeared to interfere.   Utilizing the




Mercury Monitor  separately and in conjunction with the Catalytic




Converter,  it was estimated that the  diethyl mercury had decom-




posed  into a complex 47. 5% elemental mercury and  52. 5% (C_Hg)_




Hg.   Reagent grade diphenyl mercury was also examined as a chal-



lenge material.    However,  the  vapor  pressure of  this compound at




room temperature is too low to be effectively used.   When the sam-




ple was heated,  it  sublimed.  Condensation of the sublimed  vapors




throughout the apparatus made  quantitation impossible and left objec-




tionable contaminating residues.




          A  supply  of dimethyl  mercury was then obtained,  and used




as the challenge form for  organic  mercury in tests throughout the




remainder of the program.   The dimethyl mercury was  held in sealed




containers,  and  diluted in 1-propanol  to the required challenge concen-




tration immediately prior to each  test run.  The 1-propanol was




chosen due  to its high boiling point (97. 2 C).   The challenge mixtures




were applied to the Hi-Vol  by placing the challenge mixture  container




in   the incoming air stream,  and evaporating the mixture into the




Hi-Vol from a wick-feeder  protruding from the container.  The  liquid




challenge  volume was preset to  be totally  evaporated during  the test




period.  If  there was a  residual challenge volume, it was measured



as accurately as  possible and subtracted from the anticipated calcu-



lated challenge  level.
                                2-21

-------
2.4.4  Ambient Air  Challenges




          Some ambient  level of elemental mercury was always pre-




sent during the test runs carried out during the program.   Background




adjustments were made to compensate the collected data for  this




effect.



          At the end of the program, a final long duration ambient




air run was made utilizing the  final Prototype collection system.  In




this run,  no "artificial"  mercury challenge was  added over the normal




mercury level found in the Pomona,  California atmosphere.   Results




of this test are presented  in Section 2. 9. 7.






2.5   AIR TRAIN  CHALLENGE  APPARATUS




          In order to facilitate  near real-time measurements of mer-




cury  vapor challenge levels,  as well as obtain collection efficiency




data on collection  canister configurations under test, it  was decided




to utilize the GEOMET Model 103 MAM as an ancillary  device within




the air train  challenge system.  The data collected  with the M103 was




then used,  in later recovery analysis runs,  to correlate the  calcu-



lated mercury challenges on  collection  canister absorbents.   This data




was correlated directly with  an atomic absorption spectrophotometer




(AAS) (Perkin-Elmer Model 303).   The Model 103 was set up and




operated with the mercury vapor source  described in Section 2. 4. 2




above.   A part of the checkout procedure was a  baseline calibration




of the instrument.   A typical graph of that calibration is  provided in




Figure  2-5.   A sampling probe was installed to remove approximately



1 CFM  of  the air passing  through the Hi-Vol sampler and  supply that
                                 2-22

-------
  600
i 400
D
M-
rt-
05
   200
  hO
  I
  ro
                 Room Temp: 28  C
                 Date:  7/19/72
                 Hg Temp:
                 Grid:  012
                 Model 103 S/N   020
                                                           Figure 2-5  GEOMET Model  103 Instrument Calibration
                                                                                                                     250
                                                     Mercury (nanograms)

-------
Room Temp:  28 C
Date:  7/19/72
Hg Temp:
Grid:  012
Model 103 S/N  020
                                                   Figure 2-งk  GEOMET Model  103 Instrument Calibration ';•:!•:::
                                                   tฑfatrttattt^|4J4lป^U44J4Um^^4t.44-;^{U-tlU.i!l-Ul4i.U .|UU,:..|.^;^r-,-t-rr:rhr?TTh--r rr^hrrTtrrrHrr::
                                                                                                                           250

-------
air sample to  the  Model 103.   Following preliminary mercury chal-




lenge testing,  it was found that the  sensitivity of the Model 103




required dilution of the incoming sampled air to provide accurate and




reproducible readings  at the higher mercury  challenge levels.  A




dilution step was  added to the  system and calibrated to  determine




validity of incoming  mercury challenge levels, background and over-




all test results when the  diluter was in use.   The  sampling train then




in use is depicted in Figure 2-6.




          An interim Hi-Vol sampling  arrangement  was  instituted




wherein the Model 103 probe was positioned within  the collection  ple-




num to monitor collection  efficiency of the absorbents during  each




challenge run.   A critical orifice,  with pick-up connections for a




Magnehelic gage,  was installed for monitoring air  flow  through the




stacked canister system.   The  details  of this interim air sample




monitoring mode are provided  in Figures  2-7 and  2-8.   This  new




method allowed positive  control over air volumes passing through




the canister,  which was critical to absorbent collection  efficiency




data calculations.   It was  felt,  however, that the Model  103 should




monitor  the mercury challenge  level rather  than possible break-




through (loss  of collection efficiency) in the  absorbent canister system.




This  decision  was supported by the  fact that no break-through had




occurred in any of the high level mercury challenge runs.   Therefore,




the Model 103  canister sample  output probe  was  sealed  and  reinstalled




on  the Hi-Vol  sampler exhaust  downstream  of the  blower housing.




This  final change to the collection  plenum is  shown in Figure  2-9.
                                 2-24

-------
Air and Hg
Challenge
  Inlet
             Sample/
             Air Mix
             Plenum
Diverter Line (To Exhaust)
                                   GEOMET
                                  Model 103
                                    MAM
   0-36 1/min.
   Flowmeter
                                                      Ag Filtered Room
                                                         Air Inlet
^Oj.2 1/min.
 Flowmeter
                                                          Dilution
                                                    Flow Valve
                                        Excess Sample
                                       Air to  Exhaust
                          Air Pump
                             CFM)
             \
                                                                           Model 103
                                                                            Exhaust
                    Figure 2-6   Mercury In Air Sampling Train
                                       2-25

-------
Canister
Sample
Output
                                                           Air Bypass  Control
                                                                 Ring
                                                           •Mating Connection
                                                           'for Hi-Vol Sampler
                                                             Upper Ducting
                                                           Partial Outline of
                                                           Canister Position
                                                        'Auxiliary Sample Port
Canister Support
                                                       Critical Orifice Plate
                                                             Assembly

                                                      '••Pick-Up Connections for
                                                          Magnahelic Gage
                                                             Mating Connection
                                                                for Hi-Vol
                                                              Sampler Blower
                          Figure 2-7

     Canister Holder and Sampling Plenum for Hi-Vol Sampler
                               2-26

-------
                                   Particulate Filter
Hi-Vol Duct
Sample Plenum
Canister Sample
  Output
                                              w
                                                    Upper Collection Canister
•Air Bypass Control Ring


Lower Collection Canister

Canister Support
              Magnahelic Gage
                (Canister Air
                Throughput)
                                   'Critical Orifice Holder
                            Figure 2-8

       Collection Canister/Hi-Vol Sampler  Interface Configuration
                                 2-27

-------
                                      m.
Interim
Canister
Probe
Output
   tv
   i
   ro
   00
               Final Collection  Plenum  Configuration

                                  Figure 2-9
                                                                                 Calibrated Bypass Air Control Ring
Magnahelic Gage
Canister Monitor
                                                                           Calibrated Total System CFM Gage
                                                                                  Air  Sample Probe
                                                                                  (Hi-Vol Exhaust Position)

-------
          During the latter part of this program,  GEOMET  decided




to miniaturize the  entire  Air Train Challenge Apparatus described




above  (Ref.  Figure 2-6).   Flowmeters  measuring  in the ranges  of




0-5 and  0-25 1pm  were purchased and the entire dilution system was




mounted on the side of the Hi-Vol  sampler shelter.   All tubing con-




nections, including a column for  silver-treated alumina pellets for




mercury-free dilution  air, were converted to 316  stainless steel.   A




positive  pressure  diaphragm pump was  installed for  precise control




of sample air from the Hi-Vol to  the Model 103.   This configuration




has created  a  simple and compact test  arrangement  which allows a




more convenient work package  and portability of the test system.




The final apparatus is depicted in Figure 2-10.






2. 5.1  GEOMET Model 103 - Mercury Air Monitor






2. 5.1.1  General Description




          The  experimental measurements of mercury in air streams




utilized  for controlled test purposes were obtained, in part, with the




GEOMET Model 103  Mercury Air Monitor.  A schematic diagram of




the M103 is  shown in Figure 2-11.  This  device was set to produce




an analysis every  3-6  minutes depending on the level of mercury in




the gas.  For organic mercury compounds the  Model 103 was coupled




with a Catalytic Converter (Module 109) which reduced all  compounds




to elemental mercury  for analysis  (Figure 2-12).




          The Model 103 operates  on the principle  illustrated in




Figure  2-11.   Air  is drawn into the instrument  at  pre-selectable flow




rates  and sampling time cycles across  a silver collection grid which






                                 2-29

-------
Complete Prototype Instrumentation  Assembled with Test  Apparatus.
                                   2-30

-------
                                                                                                       Exhaust
  Air_
Sample
      Figure  2-11:   Functional  Diagram,
                      Model 103
                                                                                                              Blower
[SJ
                                                      GEOMET
                                                   Cmlytic Converter
                                                                                GEOMET Model
                                                                                  103 or 104
                                                                                 Mercury Air
                                                                                  Monitor
                         Figure 2-12:  Model 103 with  Catalytic  Converter

-------
serves to  concentrate  the  sample.   Readout is achieved  by use of




sequential  heating  of the two electrically independent grids  sections.




During heating of the first section  by direct  passage of electrical




current through the silver wire,  collected mercury is  shifted to the



rear or  second section.    Adsorbed impurities  or  potential interfer-




ences, which are not strongly bound to  silver, pass into  the  photo-



meter  for  quantitation.   The signal,  if any,  is stored  electronically



for subtraction from the signal resulting from heating  the second grid




section.   Heating of the second  section  releases  the collected mer-




cury sample plus any  collected interferences  into  the photometer for




quantitation.   The readout procedure is  automatically controlled,  it




requires 70  seconds.   The entire readout cycle requires  2.0  minutes.



At 70  seconds, the corrected  peak signal voltage  is displayed on a



digital voltmeter.   Connections are provided  for  simultaneous use of



a printer or strip chart recorder.   The  collection, readout and data




presentation cycle is  adjustable  for continuous air monitoring over




long periods of time.



          The  schematic diagram of the  electrical system is  detailed




in Figure  2-13.






2. 5.1. 2  Improvements to  Model 103



          Field testing of  the  original Model  103  showed  two weaknes-




ses:  (1) instability in the  UV source output was  not detectable.   This



caused poor reproducibility  at low  mercury  levels,  and required con-




stant  vigilance to avoid variations from  calibrated  performance,  and



(2)  line power variations  resulted in damage  to the grid.
                                 2-32

-------
                                                                                                   O—^2t—HS>
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2. Q DE.MOTIS  -~lปE  NUMBERS
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                                                                       Figure  2-13

-------
          Both problems have been eliminated by  redesign:   (1) an



automatic lamp intensity control has  been added,  and (2) an  SCR




current  control has  been  added to both grid circuits.   The circuitry




involved is  shown schematically in Figures  2-14 and 2-15.  Other new




features include (a)  a shutter,  (b) Instrument  Zero  Adjustment and




(c) Span Adjustment.






2.5.1.3  Details of  Changed Features




Automated UV Lamp Current Control




          An  automated UV lamp current control system is now




included in  the  Model 103  Mercury Air Monitor.   This "loop"  system




obviates the necessity for  manual  adjustment of the UV lamp,  and




offers stable  lamp conditions for the life of the bulb.   This system




contains two functions:




          1.  "Sampling" error  voltage control,




          2.  "Hold" error voltage control.




The purpose of the  "Sampling"  error voltage control is to maintain




the UV lamp  intensity,  measured at the photodiode, at a constant




level prior  to the  peak reading cycle.  The "Hold"  error voltage  con-




trol maintains a fixed,  but non-controlling,  voltage to the lamp during




peak  reading  cycles.




          On  instrument start-up,  the Model 103 Mercury Air Monitor




is set up ready for  air sampling,  the power switch  is  actuated to the




"ON" position and the instrument operation observed.   The operator




then depresses the manual READ pushbutton.  The purpose of this




action is to initially start  the UV lamp,  and therefore  actuate the
                                 2-34

-------
                                 ฃ36     KZ5
+Z4V0C
                                                         -L/SVOC.
                                                                                   Figure 2-14:   Recent
                                                                                   Improvements in Lamp
                                                                                   Controls  and Adjustment.
            UV
            4UK.KCNT
            U&ULAfTUL
                                                                                                                       /PC
                                                               Figure 2-15

                                                               Recent Improvements in  Model 103 Grid  Control
                                                                     Circuitry.

-------
automated UV lamp  current control  system  and instrument readout




cycle.  The DVM readouts for the first fifteen  minutes are  considered



invalid  due to the need for UV lamp stabilization.



          Once the lamp  is actuated by  the  first READ cycle,  the




lamp voltage is  automatically  controlled.  Current fed to the lamp




is monitored by a transistorized current leveling  circuit.  Should the




output voltage of the lamp  (measured  by the photodiode)  vary above or



below the  preset value (normally 9.85 -0.20 volts),  the  current is



automatically reduced or  increased to maintain  the desired value.




          During the sample readout cycle,  the control system  shifts



to the "Hold" error voltage control  system.   Coincidental to the sample



signal being measured  by the peak detectors,  the  variable voltage con-




trol is  by-passed  and the lamp is held at a  constant level value and



not adjusted during the peak reading  cycles.  This provides  a  constant



unchanging  baseline  voltage over which the  sample value is super-



imposed.



          Following  the sample readout,  the lamp system returns to



the "Sampling"  error voltage control mode.   Here, the error voltage



control  is  used to sustain the  UV lamp  temperature  and  activation con-



currently with the use of a mechanical shutter positioned in front of



the photodiode.   This  condition maintains  the lamp in a ready state,



and the shutter extends the life  of the photodiode  by  cutting  off UV



radiation  from the lamp.



          The shutter,  which has been installed in front  of the photo-



diode, remains in the closed position  during the sample  collection
                                2-36

-------
cycle.   The shutter blade interrupts the passage  of  light from the UV
lamp to the photodiode.   During the "Read" cycle the shutter is lifted
out of  the light path and allows the full output  of the lamp to reach
the photodiode.   This  action occurs  prior to  the  entry  of the  air
sample into the photometer.  The shutter  is timed  to close following
the readout cycle,  again protecting the photodiode.   The  shutter has
increased the photodiode life to something greater than  30,000 read-
out cycles.

Instrument  Zero Adjustment
          This adjustment provides a method of evaluating any elec-
tronic  "noise" within  the  Mercury Air  Monitor, establishes that level
of noise and provides  adjustment  to  compensate for that  signal level
in the  final readout value.  This  adjustment can  be performed with
any  amount of mercury in the sampled air passing through the system.
          In operation, the  Instrument Check  Switch (located  on  the
rear instrument  panel) is moved from the "Normal" position,  UP to
the "Zero Chk" position.   The  "Read"  button,  on the front panel, is
then pushed to activate the readout cycle.  During the Peak 2  portion
of the  cycle,  the Zero Knob (located  on the front instrument  panel) is
adjusted to maintain a reading of +000,  or any other desired positive
value.   At this point,  the Instrument Check Switch  should  be  returned
to the  "Normal" position.
          This action has now calibrated the  instrument for full elec-
tronic  zero, including the collection grid firing cycle.   The  Instru-
ment Zero  Adjustment should be  made  following  any replacement of
collection grid assemblies,  and as  often  as operational  use requires.
                                2-37

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Span  Adjustment




          The Span Adjustment is used to calibrate  the  Mercury Air




Monitor upper limit readout.  The instrument zero point is  adjusted



with the Instrument Zero Adjustment,  and the Span  Adjustment is



then necessary for full instrument calibration.   The  span is adjusted




prior to shipment and generally is not readjusted by the instrument




user.   A procedure for changing the span is  included in the  Opera-



tions  Manual.   An  additional use of the Span  Adjustment is for



matching the sensitivities of two or  more Mercury Air Monitors



being concurrently utilized for air sampling  so that the same mer-




cury  vapor level  injected into all  instruments yield the same final



reading  on  all instruments.






Grid  Temperature Control




          It has  been observed that  full line  voltage is not required



by the grids for desorption of collected mercury.   By installation of



SCR current controls, the grid current is limited to a maximum of



15 amperes.  Previously  an upper limit of  approximately  30  amperes



was obtained.   Chronologically,  since  this limitation was  imposed on



the silver  grids,  no single  grid failure has been  noted in  more than



4000 hours  of operation.
                                2-38

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2.6   MERCURY ABSORBENT  DEVELOPMENT




          This  section  of the program  Final Report is devoted to




discussions  of the development of unique and  efficient collection




materials for the three forms of mercury  - particulate,  elemental




and  organic.   Rationale for approaches  utilized for each material




type is provided.






2.6.1  Selection of  Adsorbents




          The  following remarks  form the rationale for selection of




the silver on alumina adsorbent utilized as a major candidate for the




collection medium for elemental mercury and for charcoal as the




collector of  organic mercury:




          Adsorption  of elemental mercury and its  compounds from




the gas phase  onto  solids is largely a surface phenomenon.  The




amount of adsorbate,  its rate of adsorption  and the efficiency of  mer-




cury  extraction from the gas are dependent on the  specific surface




and the total surface of the adsorbent which is presented  in the  pro-




cess.  Other factors  which control the removal capacity  include  the




nature of the adsorbent and adsorbate,  the geometrical state  of the




adsorbent, the temperature and velocity of the air,  the concentration




of the mercury-containing gas,  effects of other  gases  in the stream




and the proportion of  the adsorbent surface covered as the adsorbate




collides with the surface.   In general, the  adsorbent bed  operates




efficiently until the  total capacity of the bed is approached.
                                2-39

-------
          Desirable  adsorbent properties include:

          (a)  Capacity:  15-30%  of adsorbent weight,

          (b)  Low resistance to  gas flow,

          (c)  Inertness,

          (d)  Resistance to deterioration during use,

          (e)  Regenerability,  and

          (f)   Provide  ready recovery  of adsorbate for  analysis.



          The adsorption of elemental mercury  is most efficiently

achieved on  the  noble  elements,  gold,  silver and  platinum where  the

chemisorptive mechanism resembles amalgamation.   Selection among

these metals has largely been made on the basis  of  economics:

silver is  vastly  less expensive.   Thin layers of gold on supports  have

been  utilized (References 1-7)  but regenerability of very thin films is

usually poor.  Also,  both gold and platinum tend  to  hold onto small

portions of  mercury tenaciously if present  in reasonable mass.   The

recovery  of  elemental  mercury from silver is  completed at rela-

tively low temperatures.
      Reference  1:  S. H.  Williston and M. H. Morris;  U.S. Patent
                    3,173,016 (1965);  and S. H.  Williston; U. S. Patent
                    3,178,572  (1965)

      Reference 2:  W. W.  Vaughn  and J. H.  McCarthy; U.S. Geological
                    Survey Prof.  Paper  pp D123-127 (1964).

      Reference 3:  S. H.  Williston;  Jour, of Geophys. Res,  73,  7051
                    (1968).
                                2-40

-------
Reference  4:  D. H. Anderson, J.H.  Evans, J. J.  Murphy and
              W.W.  White; Anal. Chem.  43,  1511 (1971).

Reference  5:  L. M. Azzaria;  Canadian Geolog.  Survey Paper
              No.  66-54, pp  13-26 (1967).

Reference  6:  J. J. McNerney and P. R.  Buseck;  Science  178,
              (10  November,  1972) 611 (1972).

Reference  7:  NTIS Report No.  PB-210 817.   TraDet, Inc.
              Columbus,  Ohio (1972).
                          2-41

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          Typical surface areas for various adsorbents  and adsorb-
ent supports are  shown in the following table:

                                            Specific Surface Area
                  Support                   	(m^/g)	

          Pyrex Wool (Corning, No.  3940           0.27
          Glass Fiber  (Fiberglas,  various)          0.04  -  0.16
          Activated  Alumina  (Harshaw, A1-0104T)    80  -  100
          Activated  Alumina  (Alcoa)                 100  - 350
          Activated  Charcoal
                  (Barnebey-Cheney, TCA)          1000
          Activated  Carbon (Darco)                  612  - 1190
          Activated  Carbon (PCC)                   1100
          Activated  Carbon (Nuchar)                 750
          Silica Gel (Davison)                       400 - 800
          Silica Gel (Monsanto)                     520
          Attapulgus Clays                        -^120
          Bentonite  (Filtrol)                         280
          Fuller's Earth (Floridin)                  124
          Silica-Alumina (various)                   500 - 600
          Activated  Magnesia  (Westvaco)             30  -  230

Ranges  are presented where  more than one product is available.
Surface areas may be varied  by modification of preparational  tech-
                                                                  7
niques.   For  example,  activated carbon may be made with  a 10 m /g
surface area by heating at 2750ฐC.   Steam and heat treatments may
be used to reduce the surface  areas  of all silicate structures.
 Calculated on basis of average fiber diameter and  density.
                                2-42

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          On this basis the following data show  the  surface areas

utilizable in the collection canisters (160 ml) with normal packing:

                                       Average                Total
                       Specific         Packing   Wt.  in       Surface
                       Surface Area   Density   Canister     Area
     Support	(m2/g)	(g/ml)    (140 ml)(g)   (m^)     Ratio
Pyrex Wool
Alumina (Harshaw)
Activated Carbon
0.27
100
1000
0.065
1.09
0.54
9.1
160
75
2.5
16, 000
75,000
1.0
6,400
30,000
  (Barneby-Cheney, TCA)




These data show  that utilization of a nonporous  solid such  as pyrex

wool  will minimize the total surface available for  adsorption of  mer-

cury.   (With careful packing the glass fiber  content  of a  canister might

be doubled.)  The useful surface with alumina is about 6,400 times

greater than that obtained by pyrex wool; activated carbon  offers

<** 30, 000-fold more  surface.

          While the useful surface of the supports is reduced after

deposition of silver,  particularly at  the  relatively high levels used in

these collection experiments, the Ag/Al_0, preparations  employed still

offer  approximately three  (3) orders of magnitude more surface than

would glass  wool preparations in the same  volume.   Charcoal,  used

for  collection of the organic mercury compounds is  one of  the highest

surface area adsorbents in common  usage.

          The objective of the foregoing  comparison is  to indicate the

advantages accruing by use of a Ag/Al_0, preparation for collection

of elemental mercury.  It meets most of the criteria indicated in the
                                2-43

-------
initial paragraph of  this section:   good capacity,  low resistance to




gas flow,  inertness,  resistance to deterioration during use,  regenera-




bility, easy recovery of mercury  for  analysis and  relatively economi-




cal initial costs.  Other adsorbents apparently do not meet all of




these criteria as conveniently.  However,  several other compositions




should be  examined  in order to obtain a maximal collection technique.



Two in particular, gold and silver on  pyrex wool should  be tested



further.   However,  in order to overcome  the  obvious  advantages of



silver on a porous support, these would have to  be at least  1000



times more efficient in capture of mercury  vapor (atoms)'  than is



silver on alumina.






2. 6. 2   Particulate Mercury Collector




          During the progress  of this  program,  GEOMET has utilized



the standard  glass fiber particulate filters normally employed in con-



junction  with Hi-Vol  samplers.  These Reeve Angel 934  AH  glass



fiber filters were used exclusively and gave  no  evidence of collected



sample loss with proper handling.   A unique method was  devised




for analysis of the mercury collected  on  these filters (See  Section



2.8.2.), and no problems  with the filters  were  evident in  the recovery/



analysis method.  It is assumed that  any  glass fiber filter, with the




same basic specifications,  may be utilized to collect mercury and be



amenable to the recovery /analysis  method.






2.6.3  Elemental  Mercury  Adsorbents




          At the onset of the program, GEOMET decided to manufac-




ture trial lots of silver-treated alumina in order to evaluate the  feasi-






                                2-44

-------
bility of this adsorbent type as a collector for only elemental

mercury.

          Several preliminary batches of silver-treated  alumina were

prepared with  AgNO,  from  samples of 0.125 alumina pellets (Harshaw,
                        2
Surface Area:   80-100 m /g), and 4-8  and 8-16 mesh alumina granules

(irregular  shapes).   These batches contained 2-5%  Ag by weight.

Volumes of these prototype  mercury collection substrates were  tested

in tubular  canisters (3" diameter) placed inside the Hi-Vol  sample

ducting upstream of the Hi-Vol blower motor.   Challenges utilized the

system described above.
                                      Challenge Level,
Collection  Substrate    Bed Depth       yu^ Hg/M3        Collection Eff., %


0.125 Alumina         3.0"  (300  gm)         44             64%
  Pellets
4-8 Mesh Alumina    3.0"  (350  gm)         48              96%
  Granules
0.125 Alumina         5.0"  (710 gm)         230             >99%
  Pellets
0.125 Alumina        6.0"  (855  gm)       230             ^99.7%
  Pellets
0.125 Alumina        7.0"  (1,000 gm)     230             >99. 99%
  Pellets
                                2-45

-------
          These  test results indicated that the pellets  were very

efficient in  collecting mercury vapor especially  in bed depths of 7. 0

inches even at extremely high mercury challenge levels.   Also, the

Hi-Vol  sampler  maintained ^20 CFM air through-put at this maxi-

mum bed depth.   Quantities of Ag-treated 8-14 mesh  alumina were

tested early in the  reporting  period,  but  did not give  the desired

results  due to (1) decreased air through-put through  the Hi-Vol

sampler (^20 CFM), and (2) lower collection efficiencies than the

4-8  mesh alumina granules.

          Twenty-four  (24)  hour collection efficiency  runs  were made

on several  GEOMET -prepared batches of one-eighth inch alumina

pellets  treated with  silver.  For example,  one batch  contained  silver

coating  averaging 3. 5%  by weight.   This  1, 000 gm. pellet  batch was

challenged with a constant  "medium" level of mercury (3.3yug/M  )

for 24 hours.   The  collection efficiency of this  material ranged from

an initial value of 99. 3% to a low of 94. 5% at the conclusion of the

run.  The result of this  test was  compared to similar tests  run on

pelletized alumina coated with.** 6% silver by weight.   Eight hundred

gm.  of  this material was also subjected to a 24-hour  test with a
                                               2
challenge level  of mercury vapor at 3.3 ^ug/M .  The same 800 gm.
batch was then challenged with a "high"  level stream of  elemental

mercury vapor  at a  constant concentration of 100 ^ug/M .   This latter
level is  stipulated in the Statement of Work as the maximum threshold

limit for collection.   This  GEOMET-prepared product gave collection


efficiency  ranges of  99.2 to 92.6% with the 3.3 ^ug/M  challenge,
                                 2-46

-------
                                      3
and 99.9  to  99.3% with the 100  ug/M  mercury challenge.   Figure  2-16
presents the results of these preliminary three 24-hour runs.


          During the program progress,  it became evident that the high


efficiency of the silver -treated  alumina would  allow  a Prototype system


elemental canister size of .^xZOO ml  or 180  gm of treated  pellets.   Pre-


paration of  the GEOMET  silver -treated adsorbent was refined until


the pellets  contained 5 12%  silver by weight.   Here, a 50/50  (w/v)  so-


lution of AgNO- and distilled water was applied to untreated 1/8 inch


diameter  by 1/8 inch  long cylindrical alumina pellets (Harshaw  Chemi-


cal Company,  Catalyst AL-0104, Lot 61) under vacuum.  Following  full


wetting of the  alumina support, the pellets were dried overnight at


100ฐC.  The pellets were then placed in a muffle furnace  and heated


at 600ฐC  for  two hours to drive off  residual nitric  acid.   The pellets


were  then ready to use as  adsorbent in  elemental mercury collection


canister.   These particular  pellets have shown typical  collection  effici-

                                   3
encies of 100 percent at 3.8 ^ag/M  for 24 hours and 97.1 percent at
28  Mg  Hg/M  for 24 hours.   The preparation steps have been even


further  simplified to allow preparation  of 1 kilo of  treated pellets to be


made in less than one hour.   This time excludes oven  drying  of  the


AgNO,  on the  pellets,  and subsequent firing of the pellets in the  resis-


tance furnace to  remove the residual nitric acid.   These preparations


provide excellent collection efficiency and  material balance (Ref.  Sec-


tion 2.9.2  and have been  reclaimed  for possible reuse by  additional


heating  in a resistance furnace combined with circulated air to remove


the bulk of collected mercury  on the  first reclaiming cycle.   GEOMET
                                2-47

-------
                               1O X 1O TO THE CENTIMETER 46 1513
                               IO X 25 CM             ซDf I* US.*.
100
 99
                                                                               Silver @ 100 fig Hg/M
                                                        2-5% Silver @ 3. 3 PR Hg /M
                                                                                       6% Silver @ 3. 3 pg Hg/M
                                                           12
                                                        Time, Hours

-------
feels that  silver treatment  of  alumina could be  converted,  with some

attendant processing equipment,  to an economical commercial pro-

cess.

          To  fully appreciate the rationale  that  GEOMET utilized  in

selection of silver-treated alumina pellets  over  more widely publi-

cized methods, the data presented  above in Section  2.6.1  (Ref.  1)
                                                                    *
should be  considered in conjunction with U. S.  Patent  No.  3,178, 572  ;

column 6,  lines 15  through 60:
              "The mercury-absorption  chambers 71 and  82
          contain highly effective absorption media for the
          specific  removal  of mercury from the  flowing air
          as compared with any  other  contents  of the  air.
          Useful for this purpose is glass wool having  its
          fibers  coated with pure gold.   A coating of  silver
          may also be used but  this is not as  desirable as
          gold because of its  susceptibility to formation of
          silver  sulphide under the action' of hydrogen  sul-
          phide content of the  air,  though it may be used
          in sulphur-free and chlorine-free atmospheres.
          Other metals which are  characterized by wettabil-
          ity by  a/id some solubility in mercury  may  be
          used, but none has been found  to be  more effec-
          tive than gold.   The gold may  be deposited  on
          the  glass wool  by ordinary  and convenient depo-
          sition methods, for example  by merely wetting
          the wool with a gold salt,  such as chloride,   and
          decomposing the salt  by heat for deposition  of
          the  gold.  There  may  be  used, in place of glass
          wool, nickel wool  on which the gold is deposited
          in the  same fashion or by precipitation  by the
          nickel  from a  solution of a gold salt.   A difficulty
          with  glass wool is that glass will absorb,  to some
          extent, mercury,  and consequently the dummy
          chamber 94,  containing the same amount of  glass
          wool but uncoated, will be required  to  be satur-
 ULTRA-VIOLET RADIATION  ABSORPTION ANALYSIS APPARATUS
 FOR THE  DETECTION OF  MERCURY VAPOR IN  A GAS.
 Samuel H.  Williston,  Los Altos,  Calif., assignor  to  Cordero Mining
 Company,  Palo Alto,  Calif.,  a corporation of Nevada
    Filed May 17,  1963, Ser.  No.  281,088
       6 Claims.   (Cl.  250-43.5)
                                2-49

-------
          ated to the extent of this  absorption  before  use.
          In the  case of nickel,  however,  the  absorption
          of mercury is negligible.   Other carriers of
          gold or silver may also be used,  such as alum-
          ina,  completely coated to  prevent absorption of
          water.   The general properties  of the carrier
          should  be that of a  physical form to present a
          maximum absorbing surface  of  the noble  metal
          per unit  volume,  reasonably low resistance to
          flow,  adhesion to its  absorbent coating and non-
          destructible by heat used  to  drive off  mercury.
          In itself,  it should  be non-absorptive of mer-
          cury, or  a  least exhibit uniform absorption
          thereof.   The last property may be  best  des-
          cribed  by saying that the  carrier should be  non-
          wettable  by mercury.   It  should, so as to be
          usable  in the  dummy chamber,  be non-absorptive
          of other  substances which absorb the radiation
          bands absorbed by mercury.   The noble metal
          coating on the carrier should be very  thin,
          ranging from  a small fraction of a thousandth
          of an inch to  not  more than  a few thousandths.
          The  reason for the latter limitation  is that if a
          thick coating  of gold, for  example,  is  used, the
          absorbed  mercury will  diffuse deeply thereinto
          and will  not be driven off completely in regen-
          eration of the absorbent by heat at moderate
          temperatures."
GEOMET's selection of alumina over glass wool was basically due

to the gross differences in available  surface  area for mercury col-

lection  (Ref. Section 2.6.1,  Page 2-42).   The choice of silver

rather than gold, as a  noble metal mercury  collector,  markedly

reduces  the cost of the final alumina adsorbent.  As previously

reported,  it appears that this product would  be commercially  pro-

duced easily and economically.
                                2-50

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 2.6.3.1  Commercially  Available Silver-Treated Adsorbents




           During the program effort,  commercially available silver-




 treated alumina and molecular sieve material was  purchased from




 W. R. Grace Company (Davison Chemical Division); Strem Chemicals,



 Incorporated;  and Coast Engineering  Laboratory.




           The Grace product, designated as SMR 7-4215, was stated




 to  contain 7. 5% silver deposited on 4-8  mesh alumina granules.  This




 material was  tested twice.   The first test was carried out in pre-




 paration  for a 24-hour efficiency test i. e.,  it followed all standard



 background measurements,  etc.  taken on the GEOMET  sampling train.



 A canister containing 910 gm.  of this material failed, however, to




 remove 0. 8  yUgm.  of mercury vapor contained in a 30  second pulse.




 The collection efficiency was  0% with this. challenge duration and level.



 The Grace product was  then  subjected to heat treatment  in a muffle



 furnace where it was held for two hours at  500ฐC.   When 42 gms.  of



 this material was subjected to the output of the  GEOMET Hg vapor




 source (a standard screening  procedure) at 42ฐC, it absorbed the ele-



 mental mercury vapor challenge well enough  to warrant the  heat



 treating of a 910  gm. batch of granules.  This batch was prepared



 and  entered the 24-hour  testing cycle but again failed a  30 second



 pulse of mercury heated to 42ฐC (0.8  ^ugm.).




          The  Strem material, Lot  837-S,  contains  11%  silver by weight



 on alumina pellets with 0.5 M2/gm.  surface area.  A 42 gm. aliquot




of this material  was subjected to mercury vapor at 42ฐC from  the




GEOMET Hg vapor source and collected no calculable amount of mer-
                                 2-51

-------
cury.   An equivalent aliquot was heat treated at about 1,000 C for




one hour and then challenged by the GEOMET vapor  source for




12 hours.  Inasmuch  as  this was a  lengthy  screening  test,  no  Model



103 data were  collected during this  period of time, during  which the




collection  efficiency  dropped from  ^99% to 0%  and the exact time of




collection  efficiency loss is not known.  A mass of 900 gms. of this




material was then heat treated at 1,000 C  and rerun  at this volume




and weight in a 24-hour collection test.   The treatment did not



enhance the  collection efficiency.



          GEOMET purchased 300  gms. of Silver X,  Type  13X,



12-16  mesh,  chromatographic grade molecular sieve material (Coast



Engineering  Laboratory).   This compound  is the  result of an exchange




process wherein the sodium  in the Zeolite has been completely




exchanged by silver.   The sieve was subjected to bench-scale mer-




cury  collection  tests,  and  subsequently two 100 gram batches were



included in total system collection efficiency tests  (Test  data  table



Section 2. 9.1).     Both runs gave very poor results,  insofar as  the



material  balance was no greater  than 57. 7%.   Some difficulty was



found in removal of the collected mercury with the recovery/analysis



technique.  It is felt  that this  was due,  in part,  to the initial recov-



ery furnace  configuration (Reference Section 2. 7. 4. Also, the internal




structure of  the Silver X may preclude easy recovery of absorbed



mercury  (Ref.  Patent 3,178,572 above).   Due to the short duration of



the program, and  the excellent results  of  the GEOMET-prepared



silver-treated alumina, no further effort was expended on this particu-
                                2-52

-------
ular mercury adsorbent.   It  does,  however,  have considerable




promise as a collection medium.






2.6.4   Organic Mercury Absorbents



          Many tests were carried out to evaluate the collection




capability  and  recovery characteristics  of commercially  available




charcoals  to be used for  organic mercury vapor collection.   Three




types of charcoals were evaluated:   (1) Silver Impregnated (10% Ag




by wt.} Charcoal,  lot 841S,  4-8 mesh, Strem Chemicals, Inc. ,



(2) Sulfur-Treated  (12%) Charcoal,  CB-1786,  4-8 mesh,  Barnebey-



Cheney, and (3) Activated Charcoal,  TCA,  4-8 mesh,  Barnebey-



Cheney.   All three charcoals were initially  bench-tested for mer-



cury collection and recovery characteristics.   The Strem material




collection  efficiency was  approximately  35%  that of either the  sulfur



treated or TCA activated charcoals.   The Strem material was there-



fore eliminated from further consideration as  a program candidate.



           The  Sulfur -Treated (12%) Charcoal (CB-1786) collected



within approximately 85% of the TCA activated charcoal.  The results




of tests for  evaluation of mercury recovery  indicated problems  with



the  utilization  of  sulfur-treated product, however.  This  charcoal




was found to liberate an  apparent heavy hydrocarbon-like material



when heated in the mercury recovery resistance  furnace.   The im-



purity appeared to come out of the vapor state,  downstream of  the



furnace,  and it coated the interior  surfaces of the transport tubing



ahead of the iodine monochloride collection  bubblers.  This residue



trapped some  of the mercury  vapor  being transported to the bubblers,
                                 2-53

-------
and therefore severely  affected the mercury recovery and material




balance results of these tests.   This phenomenon justified the elimina-



tion  of the  sulfur-treated charcoal from further consideration as a




useful organic mercury collector.



          GEOMET then utilized 75 gm aliquots of  Barnebey-Cheney




TCA  activated charcoal for all organic mercury collections.   This




absorbent volume, without any  special loading  or packing procedures,




occupies approximately the same volume ( s^lbQ ml)  in the proposed



Prototype collection  canister  as does the 180 gms of silver-treated



pellets utilized  for elemental mercury collection.   The collection



efficiency and mercury recovery from the TCA charcoal was excellent,



and was  reported  as the final GEOMET  choice for  organic mercury




absorbent utilized in the Prototype instrumentation.






2.7   PROTOTYPE COLLECTION SYSTEM



          The various  developmental  details of  the total  Prototype




system are  discussed throughout this  program Final Report.   The



details of the final configuration are  included here,  including fabri-



cation sketches of each component.






2. 7.1  General



          The design of the  Prototype system has been kept uncom-




plicated to  offer minimum development costs and maximum  opera-




tional characteristics.   The  materials of construction,  e. g.  6061T6



aluminum,  316  stainless steel,  PVC plastics,  etc.,  are free from



mercury upon purchase.   These materials are  utilized in  areas to
                                 2-54

-------
 obviate the unnecessary contamination by mercury forms, and where




 the  possibility  of low  mercury background  might occur,  methods have




 been devised for readily cleaning  all component  surfaces.




           The Prototype system consists of 1) a  Hi-Vol sampler



 collection plenum,  2)  two  absorbent canisters,  3) an air through-put




 control ring, 4) absorbent materials (Ref.  Section 2.6),  5) an  air



 metering system,  and 6) a Unico  550  Turbine Jet High-Volume



 Sampler with a  wooden shelter.




          Attendant testing  devices include  an elemental mercury vapor



 source (Ref.  Section  2. 4. 2),  a GEOMET Model  103  Mercury  Air Moni-




 tor  (and a M109 Catalytic  Converter Module) for  tracking  mercury




 challenge levels, and  a  Processing System for  the recovery  and quan-



 titative analysis of mercury from  particulate, elemental and  compound




 vapors,  respectively.   (Reference Section 2. 8).






 2. 7. 2  Hi-Vol Collection Plenum




          The major  component of the Prototype  collection system is




 the  Collection Plenum which is inserted  between  the Hi-Vol blower



 motor housing and the adaptor ducting.   The plenum is attached with




 standard threaded  screw rings  which fit commercially available  Hi-



 Vol  samplers.   Without the canisters,  the plenum contains canister



 supports,  a  removable calibrated air bypass control ring,  and a cali-




 brated orifice plate for the monitoring of canister air through-put.



 There are feed-through connections, from the orifice plate,  through




 the plenum wall for the  attachment of  a Magnehelic  pressure gage.



 A drawing of the assembled system  is provided  in Fig.  2-17,  and a



 photograph of the unit in Fig.  2-18.   Fabrication drawings are pro-




vided in Figures 2-19 through  2-27.





                                2-55

-------
       8 Inches
       6 Inches
  26
Inches
       12 Inches
                                           	<&0
                                               Calibrated Bypass Air Control Ring
                                                            Magnahelic Gage
                                                            Canister Monitor
                                        Calibrated Total System CFM Gage
                              Figure 2.1?

               Hi-Vol Collection  Plenum Installed in Place
                                   2-56

-------
                                   Figure 2-18
Collection  Plenum  and Canister Assembled  onto Hi-Vol  Sampler

                                     2-57

-------
                                        Air Bypass  Control
                                              Ring
                                        •Mating Connection
                                        'for Hi-Vol Sampler
                                          Upper  Ducting
                                        Partial Outline of
                                        Canister  Position
                                      Canister Support
                                    Critical Orifice Plate
                                         Assembly

                                    Pick-Up Connections for
                                      Magnahelic Gage
                                                Connection
                                            for Hi-Vol
                                          Sampler Blower
      Figure 2-19
Hi-Vol  Collection Plenum
            2-58

-------
 .\-ZSV\IM_L.
I
U1
vO
                                                 Figure 2-ZO

-------
       Figure 2-21
KJO,
              2-60

-------
4:2.50-e> TWD
                                                Figure 2-2Z
                                                                N/OO\1=-.
                                         •NO.
                                                                                                          BY '
H . H ,
                                                                                                                O IS

-------
   FUUSH
t\ป




N
                                              Figure 2-23

-------
                       D\A. X IVZO DV,
Figure 2-24
     2-63

-------
•Z.,\-2.5
                              -.500
                               Figure 2-25
                                '. U0\o\-Tlo
                                                                \OJ-ZAlT2-
                                        2-64

-------
\ O --
                                               X \.oVo~DP,
y	r—^	' —ir *LT
     ^"1 ~~_ .	     	  ^^^_^^^_^__
                                                          TV4 "D ,
               Figure  2-26
                           "TUSH
          SI
                                                10
                      2-65
                    <5fflHR>

-------
Figure 2-27
    \-bAo
                                        JIT.
        2-66

-------
2. 7. 3   Collection Canister  Design




          The physical  characteristics of the Prototype system




canisters were established  as a result  of  extensive  studies of Hi-Vol



air transport characteristics,  mercury collection material  surface




area and packing parameters, and evaluation of the  wide range  of




mercury  levels which must be  collected and  recovered in analysis.




The canisters were scaled  down from a 1000 gm volume to 180  grams



(/v 160  ml) of adsorbent for elemental mercury collection,  and a like




volume containing 75  grams of absorbent for organic mercury col-



lection.   These  canister volumes, at ซv 20% air through-put of the




Hi-Vol total at 20 CFM,  provide the ability to collect and analyze



over the  entire collection range from a few nanograms of mercury




to 100,000 is ng/M  as stipulated in the  contract Statement of  Work.




          The canisters will  be  utilized for mercury collection,




sample transport and  storage and are therefore to be  light weight




and durable.   PVC  plastic  canisters are well suited for  this  use,



and heavier  more expensive materials of  construction  (e.g. stainless



steel) were therefore  unwarranted.   The canister bodies, screen



closures and  plugs are recyclable, and  easily cleaned for reuse.   A



drawing depicting the  assembly of the canisters within the Hi-Vol



plenum is provided  in Figure 2-28.



          The design  for  the  prototype  collection canisters  is  pro-



vided in Figures 2-29 through 2-31.   The  canister bodies are fabri-




cated from sections of plastic tubing and closures which retain the



absorbents are held in place  by a close-tolerance friction fit.   The



Type  "A"  end closures,  Figure 2-29, are  fabricated with a captive






                                 2-67

-------
screen  section which prevents absorbent loss yet allows air sample



through-put.  The center dividing  closure,  Type "B" configuration,




is fabricated  by  joining together parts of two Type  "A" closures.




This minimizes the number of special fittings  and  decreases tooling




and fabrication  costs.   The canisters  may be easily emptied and




refilled in the field,  or shipped intact in plastic shipping containers




back to a central laboratory for  analysis and recycling.
                                 2-68

-------
 Hi-Vol Duct
Hi-Vol  Plenum
                                    Particulate Filter
                                              Sffi
                                                     Upper Collection Canister
•Air Bypass Control Ring


Lower Collection Canister


Canister Support
                                                           Magnahelic Gage
                                                             (Canister Air
                                                              Throughput)
                                    Critical Orifice Holder
                            Figure 2-28

       Collection Canister/Hi-Vol Sampler. Prototype

                        Interface Configuration
                                  2-69

-------
  5. 5 Inches
 5. 5 Inches
                             -Type "A" End Closure
                                1. 75 Inches

                             -Typical Thin-Wall Plastic Tubing
                             -Type "B" Multiple-Use  Closure
                            -Type "A" End Closure
               Figure 2-29
Prototype Multiple-Use Collection Canisters
                     2-70

-------
N
1
                                        5.50
                                                                            1
                                           Figure Z-30
                                                         BOOV

-------
.002
          \.T50
           "DIA.
                            \.1AO
                             T5\/V
                           (•s?foc.vO
                                                   .001 _^
                                                \ 5-0
                    Figure 2-31
                       2-72
ซEDIEป

-------
2. 7. 4   Recovery Analysis  System




          The  processing method is  fully described in Section 2. 8,




and with the exception of the recovery furnace  is  non-deliverable




under the contract.  The recovery furnace consists  of (1)  a furnace



insert,  which is used for holding absorbents within the furnace,  and




(2)  a  heavy duty crucible furnace capable of heating  samples  in  the



range of 0-2000ฐF.



          The  aliquots of absorbents are placed in a modified crucible



and attached to a  support fixture which is lowered into the crucible



furnace.  The support fixture  has been designed to direct a stream



of transport air through the heated collection material and carry off



the liberated mercury to a series of EPA-type  liquid collection  bub-



blers containing iodine monochloride solution.   A  detailed assembly



drawing and fabrication  sketches are provided in Figures  2-32




through 2-38.






2. 7. 5   Demonstration to EPA  Program Monitor



          Phase V, of the contract Statement of Work,  required that



GEOMET conduct  a demonstration of the  operation of the Prototype



collection device before  the  cognizant Project Officer at the National



Environmental Research  Center,  Research Triangle Park,  North



Carolina.



          In light  of the attendant processing equipment, recalibration



procedures  and nature of the collection device,  the cognizant Project



Officer  was invited to witness  a demonstration  of  the Prototype



instrumentation at  the laboratory of the  GEOMET Office of Experi-
                                 2-73

-------
mental Development in Pomona,  California.   On Tuesday,




20 February,  1973,  Miss Eva Wittgenstein,  Program Project Officer




(EPA Laboratory Measurements Research Section,  Chemistry and




Physics  Laboratory), reviewed the development effort on  the program




and witnessed an operational demonstration of the  Prototype instru-




mentation.
                                2-74

-------
                                t
Furnace Cover
                       To EPA-type
                       Bubbler
                       Train
       Sample Vapor
       Outlet  Tube
        (Collect)
  Outlet Tube
  (Crucible   Support
   Tubing)
 Quick-Release
 Pin for change
 of  sample
 crucibles.
Support Disc
       Insulation

       Crucible
       Furnace
       Body
                                                                 Heated Furnace
                                                                    Cavity
                                                               Crucible Lid
                                                                "Cover
                                                              Metal  Crucible
                                                               Air Inlet Slits
        Figure 2-32

  Recovery Crucible
  Furnace Details
                                      2-75

-------
                          OS)  I 7? SO B.C.,
         C.OVE.R
MAT. '.



NO.
                 ORES
Figure 2-33
                           "DRAVNM
    2-76

-------
NO.
         Figure 2-34
           2-77

-------
as
    ts>
    i

                                               K10.

-------
CO
   MO
Figure 2-36
                                                       . VA .

-------
SEOMETTJMC.
                                        •J7.S
Figure 2-37







       A-
                                     2-80

-------
                         .B HOUES
                   .OA-O
KIO.
   Figure 2-38
     2-81
                             BY*.

-------
2.8  RECOVERY  ANALYSIS PROCEDURES




          GEOMET was  charged with the responsibility of providing




both a "removal" and "transfer"  step as  necessary in quantitative




recovery  and analysis  of all three forms of mercury.   The following




sections describe the development of this methodology  and attendant




equipment.






2. 8.1  Recovery System Description



          The  recovery  system for the  Prototype mercury  collection




instrumentation was  initially the same for all three forms  of collected




mercury.   It was  based on a furnace and bubbler technique.   As the



program  progressed, it  became apparent that the  elemental mercury




adsorbent and  organic  mercury absorbent could be handled  by this




method,  but a better procedure was developed for particulate mer-




cury recovery from the  glass  fiber filter.



          The  final system,  referring first to the adsorbent (silver-




treated alumina for  elemental  mercury  vapor) and the absorbent




(activated charcoal for  organic mercury forms) is shown in Figures



2-39 and 2-40.  The mercury sources  feed elemental  and organic



mercury  forms to the  Hi-Vol  sampler.   A  portion of  the total  air



stream is metered through the canisters  where the two forms of



mercury  are selectively collected.   Following the collection cycle,



the two canisters are  emptied into storage  containers, labeled  and



sealed.  A  ten (10) percent aliquot of the adsorbent is weighed out




for processing.   An equal amount of the original adsorbent, which



was not used in  the collection cycle, is placed into the  resistance
                                 2-82

-------
00

Hg
Source

GEOMET
M103
M. A. M.
t
^"^y /

M
S
<
ixing and
Aliquot
eparation


Aliquot

Collection
Hi-Vol Sampler Adsorbent
and
Collection Canisters
Furnace
Insert


Vapor
^•^


Resistance
Furnace




I


^k-
L^


1


EPA Collection Bubbler Train


Collected
Liquid
Sample
                              Figure  2-39 Mercury Challenge Collection Method

-------
                          Serial
                         Dilution
                          Aliquot
t\>
i
oo
     Collected
       Liquid
      Sample
Liquid
Vapor
                                                                   Silica Gel Bed
Gold
Plug
•
Induction
Furnace
Vapor

AAS


AAS
Recorder
                                   Diluted
                                   Sample
                                  Moisture
                                    Trap
                                           10% Sodium
                                          Borohydride
                                            Solution
                                             Figure  2-40.   Analytical Method

-------
 furnace  for  processing as an analytical  blank  sample.  Samples are



 held in  a  nickel alloy crucible  which is  lowered into the vertical



 furnace  cavity.  The furnace has  been pre-heated to a controlled



 range  of from 500ฐ  to  700ฐC.  The crucible holder is  ducted to a



 EPA-type collection bubbler (iodine  monochloride) train and vacuum



 source.  (Ref.  Fig 2-39) All furnace  and  bubbler train components,



 except the crucible, are of stainless steel or  Pyrex  glass.   Following



 a thirty  (30) minute collection  cycle, the  sample blank and sample



 bubbler  collection  fluid is processed through the  second half  of  the



 processing apparatus.   The  sample, serially diluted as necessary,



 is processed using a modified version of Method 2. Determination  of



 Mercury in Gaseous Emissions From  Stationary Sources.   Federal



 Register,  Vol.  36, No.  234,  7/12/72,  Page 23250.  Here,  the



 released mercury  is pumped onto a  gold wire  plug in an  Induction



 Furnace and recollected.  The  I. F.  is then fired  and the mercury



 passes through an  Atomic Adsorption Spectrophotometer (AAS).  The



 recovery and analysis  process  is now  complete.   This  method was



 used for  all  alumina and charcoal  absorbent processing throughout the



 program.  Certain modifications and refinements were  made  to this



 system.   A  discussion of those refinements  and the improved  method



for processing the particulate filters is presented  below.





 2. 8. 2    Analysis of  Particulate Mercury Samples



          The  first trial analysis of particulate glass filters,   con-



taining mercury  challenges, were  carried  out with the resistance



furnace approach as  utilized for the absorbents as described  above.







                                2-85






                                                                    CEO,.

-------
A  method was devised to fold the  filters,  on removal from  the




Hi-Vol  sampler following collection, in order  to  maintain sample




integrity and  avoid  any sample loss.   This portion  of the processing




technique is still valid.   There did appear,  however, to be  some




difficulty in obtaining reproducible air  flow through the folded filters




when they were placed in the recovery furnace for  pyrolysis.  There-




fore, a better and  simpler  method of  analysis  processing was devel-



oped and tested.  The glass filters were folded into  a compact




bundle (xvl" square x 1/2"  thick)  and placed into  a wide-mouthed



inert plastic jar containing  100 ml of IC1 (iodine monochloride)  solu-



tion.   Several 3mm glass beads  were added and the jar was tightly




capped.   The container was then  vigorously shaken so that the beads




maserated the filter.   The  mixture was allowed to stand overnight




to insure adequate mercury takeup by  the IC1  solution.  Aliquots of




the mixture were then  centrifuged  to separate  the filter  metrix from



the IC1 solution.  Portions  of the IC1 were serially diluted as neces-




sary  and analyzed through the AAS for recovered mercury.   This




procedure could be  simplified by  use of automated  shaking devices,



or sonic separators in future development of the  total Prototype sys-



tem.   However, for the  glass fiber filters it works adequately.






2.8.3  Analysis of  Adsorbent Pellets




          Initial mercury recovery runs,  utilizing silver-treated



alumina  adsorbents  for  elemental mercury, were made by placing




the pellets  in an open  cylinder  positioned in the resistance  furnace.



Transport  air was pulled from the furnace to  the EPA-type,   iodine-
                                2-86

-------
monochloride collection bubblers through stainless  steel tubing.




These preliminary tests indicate that 790% of the mercury was




released when the furnace reached a temperature of >^.350ฐC.  This




release was in the form of a rather large "pulse" and tail-off of




mercury vapor was still in evidence when the  furnace reached 505ฐC.




This  phenomenon was< due  in part to thermal gradients found in




heating the mercury-laden alumina adsorbent,  and to  the  construction




details  of  the furnace tube.  A cast  iron tube  was then used as  a




replacement for the alloy  steel liner.   This  alteration,  while nega-




ting any apparent problems with mercury vapor hold-up during the




absorbent  heating procedures,  still lacked the  necessary handling




convenience  necessary for rapid laboratory analyses.   A  conceptual




design for the final Prototype  system was  reported to EPA,  and that




design is provide in Figure 2-41.   This exact design was  never fully




completed.   Instead, a  less  complicated design was formulated




(Reference Section 2. 7.4 above) and  utilized on the remainder of  the




program.  This furnace insert  method allowed the use of a standard




tube furnace and  obviated the  need for  a cast iron  or  other metallic




furnace cover  liner.   The need for a human  engineered handling  sys-




tem was very  important to the  success of  the  adsorbent  recovery




procedure.




          The  analytical procedure for  recovery of  mercury from the




absorbent  pellets  began  by removal of the pellets from the collection




canister.   The  pellets  should be transferred to plastic shipping/




storage containers,  sealed and  labeled.  At time of analysis, the




adsorbent  should  be well mixed to achieve uniform mixing  of the






                                2-87

-------
Sample Output
   Probe
                                            Air Inlet
                                              Iron Furnace Cap
                                                     •Removal Framework
                                                   Iron Furnace Liner
                                                       Sample Cup
                                                   Resistance Furnace
                                                       Elements
                                                Temperature Gage
                     Figure 2-41

  Conceptual  Mercury Recovery Resistance Furnace


                           2-88

-------
 mercury load throughout the adsorbent lot.   The final Prototype




 system  canister design holds 180 grams of the silver-treated alumina.




 A 10% aliquot is weighed out and placed into a cold crucible,  assem-




 bled  onto the furnace  insert, and placed within the pre-heated resis-




 tance furnace ( ป,600-700ฐC) and connected to the  EPA collection




 bubbler  train.  Air  is drawn through the pellet bed and into the




 bubbler  tain for 30 minutes.   This has proven to be  sufficient time



 to heat the adsorbent  and transport  all the elemental  mercury into



 the liquid  (IC1) collection bubblers.   The 45 ml bubbler volume is




 collected in clear  glass  storage bottles and transfered to  the  proces-



 sing  apparatus described  in Section 2.8.1,  above.




          Refinements were  made over the duration of analytical runs




 made during  this program.  The tubing from the furnace to the EPA-



 type  collection bubbler train was reduced to a minimum to prevent



 any fallout  of mercury being transported to the bubblers.




          Extremely high AAS readouts were occasionally  experienced



when  firing the collected mercury (from the samples obtained out of




the recovery  process furnace bubblers) off  the noble  metal wire plug



in the induction furnace.   In one or two instances,  this phenomenon



occurred during  the  recheck of bubbler and pellet  blanks.   In  order



to circumvent the  possibility of  elemental mercury  vapor induced by




external or other laboratory  procedures from interfering with ongoing



AAS readouts of critical test runs,  two additional bubblers were



installed in the vapor  transport tubing.   The  first of these contains




approximately 10 ml  of a ฃ.10%  sodium borohydride solution and is
                                2-89

-------
 located  immediately before the sample bubblers containing the alka-




 line hydroxylamine solution  used in this modified Hatch and  Ott pro-




 cedure.   The second is a spray  trap.  It was found that apparently



 some  portions  of the reducing  solution used in  the  analytical method




 pass into the tubing to the induction furnace from the bubblers.   The




 air  stream transports droplets which line the passages  and subse-




 quently  trap elemental  mercury vapor.   This mercury source appar-



 ently causes  intermittent,  inexplicable  signals in the AAS.   The



 additional  sodium borohydride bubbler scrubs off any interferences



 and  droplets,  but allows the  passage of mercury vapor to the AAS.



 The second bubbler is  used  completely empty.   It  acts as a  spray



 trap and as  additional protection  for moisture removal  from the




 sample  air stream.   The basic sample recovery and analytical method



 utilizing the resistance furnace, modified  Hatch and Ott  procedure,



 modified analytical  method,  induction furnace and AAS was fully  suc-




 cessful in  processing the silver-treated alumina mercury adsorbent,



 and  the  activated charcoal mercury absorbent.






 2. 8. 4  Analysis of  Charcoal Absorbent




          The  activated charcoal used to absorb  inorganic  and organo-



 metallic  mercury vapors was analyzed  in the same manner as the




 adsorbent pellets.   This method was both  practical, from a  technical



 point of  view,  and economical.  It allowed the same equipment devel-



 oped for the processing and  analysis of the pellets  to be used for the



 activated charcoal.  The only minor  difference in the procedure was



that  the  total  charge per canister of charcoal was 75 grams rather
                                 2-90

-------
 than 180  grams.   The  difference in the  weight,  of course, is due to




 the densities and  packing characteristics of the two different mater-




 ials.   The charcoal was  also  processed in 10% aliquots in the  resis-




 tance furnace,  and the collected mercury passed  through the GEOMET



 processing equipment.






 2. 8. 5   Other Analysis Methods




           Due to the modification of processing technique for the




 particulate filters, it seemed  appropriate to  examine the  IC1 "soaking"




 technique  for both the silver-treated alumina adsorbent and the acti-



 vated charcoal absorbent.




           The leeching  of mercury from activated charcoal by  the



 IC1  solution was not feasible.   Bench studies indicated  a chemical



 reaction between the two constituents, and  the  release  of large quanti-



 ties of iodine.   This reaction  precludes the use of IC1 as a  method




 for  chemical removal of  the mercury from this absorbent.   Other




 chemical reagents should be evaluated as part of a liquid/solid  sys-



 tem for processing of the activated charcoal absorbent  by a similar



 extraction method.




          The results from application of IC1 to the  silver-treated




 alumina appeared  to be more favorable.   Trial batches  of the alumina



were given 30-360 minute soaks in IC1,  and this  solution was run




through the GEOMET processing train.   Recovery  of elemental mer-




 cury appeared low (  ^ 50% of collected load) initially,  but the method




did appear to operate properly  with the  alumina substrate.   Due to



the short duration  of the  program,  this  potential  change was  not fully
                                2-91

-------
  examined.   Future evaluation should be carried out with IC1  and/or

  other chemical  oxidants/extraction solutions compatible with both the

  alumina and the activated charcoal absorbent.


  2. 8. 6  Additional Analysis Equipment

            The GEOMET processing  system for recovery and  analysis

  of all three forms of mercury is  fully described in Sections  2. 8. 2,

  2. 8. 3 and  2. 8. 4 above.  The contract  Statement of Work  stipulates

  that other  types of equipment suitable for this processing be provided

  in this report.   In order to  provide  this information with some clar-

  ity,  the GEOMET processing system can be divided into  segments

  which may then have  substitutions of equipment as  necessary.   The

  various segments are shown  below.   Circled numbers in the  schema-

  tic  diagram correspond to  entries in the '"System Segment and Com-

  ponent" column  of the following table:

             	Furnace Insert Uj
     I

Resistance
(Combustion)
Furnace @

     I
                                         Flowmeter (4j
                                          Aspirator
                 EPA-type Bubblers   3J
                                         I
                                                               Flowmeter
                            Atomic
                            Adsorption
                            Spectrophpto-
                             meter  (8

                                                *•
Process
Bubblers
  (ฃ)
             H. F.  Induction
             Furnace
                                                            Vacuum Pump
                                  2-92
                                                                     

-------
           These segments, and  commercially available equivalents,

 are listed below to aid EPA and the Government in procurement

 activities.
 System Segment
 and  Component
                             Type
    Additional Sources or
Substitution Instrumentation
ฉ
FURNACE INSERT    GEOMET,  Inc.
 2] RESISTANCE
    (COMBUSTION)
    CRUCIBLE
    FURNACE

 3) COLLECTION
    BUBBLERS
 4] FLOWMETER
 5) ASPIRATOR,  VAC-
    UUM PUMP
    PROCESS
    BUBBLERS
                      Lindberg,  Type
                      56312-A
                      SOLA  Basic Ind.
                      Watertown, Wise.

                      (EPA Design)
                      WEST-GLASS Corp.
                      12440 Exline St.
                      El Monte,  Ca. 91732

                      Gilmont, Size 12
                      (0-2 1pm)
                      Roger  Gilmont
                        Inst's, Inc.
                      161  Great Neck Rd.
                      Great Neck,  N. Y.
                                 11021
1)  Any qualified machine
   shop.

1)  BLUE-M Electric Co.
   138th &  Chatham
   Blue Island, 111.  60406
1)  ACE Glass, Inc.
   P. O.  Box 688
   Vineland,  N. J.
1)  FLORATER Flowmeters,
   Matheson Scientific Co.
   1850  Greenleaf Ave.
   Chicago,  111.  60007

2)  Dwyer VISI-FLOAT Series
   Dwyer Instruments, Inc.
   P.O.  Box  373
   Michigan City, Indiana
                 46360
                      Nalge #6140           1)  AIRJECTOR
                      Nalgene Labware Div.    Fisher Scientific Co.
                      Sybron Corp.
                      Rochester, N. Y.
                                    14602
                                                   711  Forbes Ave.
                                                   Pittsburgh,  Pa. 15219
                      (EPA Design)
2) CHAPMAN Model, and
   RICHARD'S Model
   Aspirators
   Matheson Scientific  Co.
      (4-1,  above)

1)  Reference 3-1,  above.
                                  2-93

-------
  Con't.
  System  Segment
  and Component
                               Type
                            Additional Sources  or
                       Substitution Instrumentation
 ฉ
7) HIGH FREQUENCY
   INDUCTION
   FURNACE
  8 ) ATOMIC
     ABSORPTION
     SPECTROPHOTO-
     METER
ฎ
   FLOWMETER
,10) VACUUM PUMP
Single Tube,  LECO
Model 521-000
LECO (Laboratory
Equip. ,  Co. )
Hilltop Rd. and
   Leco Ave.
St. Joseph, Mich.
         49085

Model 303
PERKIN-ELMER
  Corp.
Main Avenue
Norwalk,  Conn.
        06856
Gilmont, Size 13
(0-12  1pm)

Neptune DYNA-
PUMP (0-14  1pm)
Universal Elect.  Co.
Owosso,  Mich.
1) ECCO  High Freq.  Co.
   7034 Kennedy Blvd.
   No.  Berger, N. J.  07049
1)  Beckman Model 979
   Beckman Instruments
   2500 Harbor Blvd.
   Fullerton, Ca.  92634

2)  Janell-Ash ATOMSORB;
   DIAL-ATOM 11; and
   Model  800
   Fisher Scientific
    (5 - 1, above)

3)  IL Model 353
   Instrumentation Lab-
    oratory, Inc.
   113 Hartwell Ave.
   Laxington,  Mass.  02173

4)  Corning Model 240
   Corning Glass  Works
   Corning,  N. Y.  14830

1)  Ref.  4  - 1, 2 above.
                                               1) Cole-Parmer Inst.  Co.
                                                 7425  No.  Oak Park Ave.
                                                 Chicago,  111.  60648

                                               2) Thomas Industries
                                                  1419 Illinois Ave.
                                                 Sheboygan,  Wis.  53081
                                  2-94

-------
Con't.
SPECIAL NOTES:
  Substitution couW be made for items
 ฉป ฎ • ฎ and ฎ bV com
  available  Mercury Analyzers.
1)  GEOMET  Model 103
   GEOMET,  Incorporated
   2814-A Metropolitan PI.
   Pomona,  Ca. 91767

2)  OLIN Mercury Monitor -
   Liquids or Gas Module
   OLIN Custom Analytical
      Inst's.
   120  Long Ridge Rd.
   Stamford,  Conn.  06904
  Substitution could bernade for the
  AAS system,  Item @ with commer-
  cially  available photometer  systems.
1)  Coleman Mercury Analyzer
   Model MAS-50
   Coleman Inst's.  Div. ,
   PERKIN-ELMER Corp.
   42  Madison  St.
   Maywood, 111. 60153

2)  Mercury Monitor
   Laboratory  Data Control Co.
   Interstate Industrial Park
   Riviera Beach,  Fla.  33404

3)  Model 2006IL Mercometer
   Anti-Pollution Technology Corp
   937 So.  Washington Ave.
   Holland, Mich.  49423
                                 2-95

-------
 2.9  PROTOTYPE SYSTEM TEST  DATA



           The development methods utilized during  the program to



 obtain a  uniform test procedure were oriented to establish  a system



 which would  collect the three forms  of  mercury efficiently  for  a



 minimum of  twenty-four  (24) hours.   In addition, bench testing  of



 sample aliquots of absorbents, as  well  as  challenge sources, was



 used often and with great success.   The purpose  of this section is



 to  present data  obtained  on  tests which  were  ^24 hours in duration.



           The full  Prototype system was challenged with all forms  of



 mercury  from  standardized  sources (Ref. Section 2.4, above).   All



 combinations of challenges were used, i. e.  elemental, elemental and



 organic,  the  latter combination plus particulate mercury, and finally



 an  ambient air test for Hg in the atmosphere.   The tests with lab-



 oratory controlled  challenges utilized  all sources  of mercury at levels


              -2              3
 from 4. 5  x 10   to 118 ^ปg/M .  The ambient air  run  analysis showed


                                  -2       3
 a total collected level of 4. 1 x 10    /ซg/M  of  elemental mercury



 averaged  over the  25+  hour  period.  One hour data during this  test

                                         3

 varied from 12 to  145 nanograms per  M .





 2.9.1  Collection Efficiency  Tests



           As  previously stated, all trial absorbents were  bench tested,



 and monitored by the GEOMET Model  103,  to ascertain break-through



 limitations at various bed depths  with variable  challenge levels  of mer-



 cury.  This method of testing was used  to screen candidate  absorb-



 ents.  Preparational  methods and individual sample batches, using the



formulation selected  as  superior  (12%  Ag/Al-0.), were  also checked.
                                 2-96

-------
 Four  (4) of the  first five  of the twenty-four tests were monitored  by




 the  Model  103 at the canister  exhaust to check for mercury  break-



 through.   The brief table below indicated the  results  of  these  tests.








 Run No.      Test Time,  Min.      Elem.  Hg.  Cone.     Collection  Efficiency
R2-07
R3-08
R4-09
R5-10
1440 (24 hrs. )
1599
1440
1440
3.8/,g/M3
28 ^ug/M3
9 ^g/M3
46 yfeg/M3
100%
97.1%
99. 96%
99. 79%
                                                   Average   99. 2%









At  the  end of  the  period  in which tese data were  obtained, the silver-




treated ( ,*, 12%) alumina  pellet preparation had been evaluated and




adsorbent performance was reproducible.   Therefore,  it  was concluded




that the adsorbent pellet  collection efficiency was  never  less  than  99. 2%




and approached 100%.   All future  testing was done with  the Model 103




utilized for monitoring the Hi-Vol exhaust (downstream of the canis-




ters and  Hi-Vol blower motor) in order to quantitate  the  actual chal-



lenge level.




          Identical procedures were used in establishing  the  collection




efficiency for  dimethyl mercury of the Barnebey-Cheney  TCA  activated




charcoal.   After a series of  bench tests in which  dimethyl mercury




was undetectable in the downstream gas exhausted from  small charcoal




canisters by use of the Model 103 in conjunction with a Converter Mod -




ule, no further measurements were made.   Thereafter the collection




efficiency was  assumed to approach 100%.



                                2-97

-------
          The  following table is representative of all the 24-hour test




runs carried out  on the program.   It  includes  the contaminant chal-




lenge tests (Runs R19-26  through R22-29),  and the ambient  air  test,




Run R23-30.   Following the table,  Section 2.9.2  presents the analysis




of the  ambient air test in detail.   A discussion of the scatter found




in the  analysis of pellet samples is included there.



          On  the  basis of the analysis of the entire ambient  air test




held in 10 batches it was shown that a standard deviation of -25%  is




to be expected for  an average  of ten results.   Thus,  the material



balances  obtained for  the single results tabulated  in Table 2-2  seem




reasonable with  one or two exceptions.



          It is apparent that the major problem involved in  achieving




reproducible material balances which  consistantly approach  100%,




relates to sampling the absorbents.   When the entire  absorbent bed



was tested,  as in the case  of  the ambient air  test, excellent recov-




eries were obtainable.  Use of 10% aliquots of the solid adsorbent



requires  very uniform homogenization of  the sample.    Since about



90% of the mercury is contained on 10-20% of the total  sample,  it  is




particularly difficult to obtain  representative samples especially when




dealing with 1/8" pellets.    This problem  is resolvable  by using the



entire solid sample or a  larger fraction such  as  50%.   Minimization



of  the adsorbent bed volume would  assist in facilitating this solution.



However  the latter  adjustment  must be compatible with  the  range  of



space velocities  (volumes  of gas/volume of adsorbent per hour) which




are acceptable.   In general space velocities of the order of 50,000
                                 2-98

-------
(vol/vol) per hour  have been employed.   The upper limit of the  range




over which this may be acceptably varied is unknown.   However,  lower




values may be  employed  provided that an  absolute quantity of  mercury




sufficient to  satisfy the threshold sensitivity of the analytical  method



is collected.   Further experimentation is recommended.
                                2-99

-------
                                                   Table 2-2
                                       PROTOTYPE SYSTEM TEST DATA
                                                      Run Number
                                    R2-07
                R3-08
R4-09
                 R5-10
Hi-Vol  Air Sampling Rate
Particulate Mercury Concentra-
tion (Expressed as  Elemental Hg)
40 CFM        44 CFM
(1.13 M3/Min)   (1. 245 M3/Min)
40 CFM
(1. 13 M3/Min)
                 40  CFM
                 (1. 13 M3/Min)
Elemental Hg Vapor
Concentration
Organic  Mercury Concentration
(Expressed as Elemental Hg)
Sampling  Time
Canister Sampling Rate
Vapor Analysis Rate
Analytical Interval
Material Balance
3.8 yUg/M"3     28
1,440 Min.
3. 56 CFM
(8. 9%)
1. 0 1pm
3. 9 Min.
62. 5%
1,590 Min.
4. 78 CFM
10. 9%)
1. 0 1pm
3. 9 Min.
100. 5%
1,440 Min.
4. 93 CFM
(12. 2%)
1. 0 1pm
3. 9 Min.
90%
1,440 Min.
4. 73 CFM
(11. 8%)
1. 0 1pm
3. 9 Min.
81%

-------
                                       PROTOTYPE SYSTEM TEST DATA (Con't. )
                                                   Run  Number
                                        R6-11
R7-12
R8-13
                                                                                               R9-14
    Hi-Vol Air  Sampling Rate          25 CFM        23 CFM
                                        (0. 71M3/Min)   (0. 65M3/Min)

    Particulate  Mercury Concentra-
    tion  (Expressed as  Elemental Hg)
    Elemental  Hg Vapor
    Concentration
    Organic Mercury Concentration     mercury.
    (Expressed  as  Elemental  Hg)
    Sampling Time


    Canister Sampling  Rate



    Vapor Analysis  Rate


ro   Analytical Interval
i—•
o
t->
    Material Balance
                      23 CFM         23  CFM
                      (0.65M3/Min)    (0. 65M3/Min)
TEST
ONLY, pre-
liminary tests with combina-
tion of elemental and organic
mercury.
1,165 Min.
4. 85 CFM
(19. 4%)
1. 0 1pm
3. 9 Min.
N/A

1,460 Min.
4. 55 CFM
(19. 8%)
1. 0 1pm
3. 9 Min.
N/A
TEST
ONLY
Organic
Mercury
960 Min.
5.1 CFM
(22. 2%)
1. 0 1pm
3.0 Min.
N/A
TEST
ONLY
High Level
Elemental
960 Min.
5. 2 CFM
(22. 6%)
1. 0 1pm
3.9 Min.
N/A

-------
                                      PROTOTYPE SYSTEM TEST DATA (Con't. )
                                                   Run Number
                                       R10-15
                Rll-16
R1Z-17
                                                                                              R13-18
   Hi-Vol Air Sampling Rate
tv>
I
H->
o
    Particulate Mercury  Concentra-
    tion (Expressed as Elemental Hg)


    Elemental Hg  Vapor
    Concentration
    Organic Mercury Concentration
    (Expressed as  Elemental Hg)


    Sampling Time

    Canister Sampling Rate
    Vapor Analysis  Rate
    Analytical Interval
   Material Balance
    LAB  TESTS ONLY

Improved Recovery Proce-

dures.
20 CFM         15 CFM
(0. 57M3 /Min)    (0. 42M3 /Min)
0.33


0.4



118


1,440 Min.


4.65  CFM
(23.8%)

4. 0 1pm


3.0 Min.
                                      86%
                                      Avg.
                                                       4. 25 mg



                                                       1.92


                                                       0.6


                                                       1,440 Min.


                                                       3. 46 CFM
                                                       (23. 2%)

                                                       4. 0 1pm


                                                       3.0 Min.
                  98. 5%
                  Avg.

-------
                                       PROTOTYPE SYSTEM TEST DATA (Con't. )
                                                     Run  Number
                                        R14-19
                                                    R15-20
                                      RS13X-21
                 R16-22
    Hi-Vol Sampling Rate
                                    22 CFM         22  CFM
                                    (0.62M3/Min)   (0.62M3/Min)
    Particulate Mercury Concentra-
    tion  (Expressed as  Elemental Hg)   92.2 mg*       8.6 mg#
Elemental  Hg Vapor
Concentration

Organic Mercury Concentration
(Expressed as Elemental  Hg)
69.1 /ig/M"*    53.3


16.0  zig/M3    7.3
                                      19  CFM          22. 5 CFM
                                      (0. 54M3 /Min)    (0. 64M3 /Min)
                                                                         --0--
                                                       --0--
                                                                             4. 4/ug/M**    4.
                                                                             2. 6 ^xg/M3       6. 7xlO~4,ซซ_g/M3*
    Sampling  Time
                                    1, 440  Min.      1, 410 Min.
                                      1,020  Min.
                 1,380  Min.
    Canister Sampling Rate
    Vapor  Analysis Rate
    Analytical  Interval
4. 80 CFM
(21. 9%)
0 . 16 1pm
3. 6 Min.
5. 36 CFM
(24. 4%)
0. 17 1pm
3. 6 Min.
3. 62 CFM
(19. 0%)
4. 0 1pm
3. 0 Min.
4.88 CFM
(21. 7%)
36 1pm
6. 0 Min.
tN)
,L   Material Balance
o
u>
                                    148%
                91. 5%
57. 5%**
Sample Contaminated.
                                                                             *   Calculated
                                                                            **   Molecular Sieve  Run

-------
                                       PROTOTYPE SYSTEM TEST DATA (Con't)
                                                     Run Number
                                        R17-23
                                                    R18-24
                                                                         RS13X-25
                                                       R19-26  (I)
    Hi-Vol Air  Sampling Rate
                                    21. 5 CFM       20 CFM
                                    (0.61  M3/Min)  (0.57 M3/Min)
Particulate Mercury Concentra-
tion  (Expressed as Elemental Hg)   	0	
Elemental Hg Vapor
Concentration

Organic Mercury Concentration
(Expressed as Elemental  Hg)
Sampling  Time


Canister Sampling Rate



Vapor Analysis Rate

Analytical  Interval
to   Material Balance
i
o
"^   Added Contaminants /Concentration
                                        5. 22 CFM
                                        (24. 3%)
                                    36 1pm

                                    6. 0 Min.

                                    126%
                4. 31 mg*


2.0 ^g/M3     78


0. 57  ^Mg/M     6. 7


1,548 Min.      1,350 Min.
                                                    4. 95 CFM
                                                    (24. 7%)
                                                   2  1pm


                                                   3. 6  Min.


                                                   90%
                                                                         19 CFM          21 CFM
                                                                         (0.54  M  /Min)   (0.59 M /Min)
                                                                             14. 23 mg*
                                                                             90
                                                                             12. 2
                                                                             1,470 Min.
                                                                         3.68  CFM
                                                                         (19. 4%)
                                      1. 9  1pm

                                      3.6  Min.

                                      46. 5%**
                                                                                           2.
                                                                                           435 Min.
                                                       4.82  CFM
                                                       (23.0%)
4 1pm

3.0 Min.


99. 9%

Chlorophenol (0. 5  ppm)

        (19. 5  ppm)
                                   *Calculated; **Molecular Sieve Run; (I) Interference Test

-------
                                       PROTOTYPE SYSTEM TEST DATA  (Con't. )
                                                   Run Number
                                        R20-27  (I)
                                                       R21-28 (I)
R22-29 (I)
R23-30 (A)
    Hi-Vol Air Sampling  Rate
                                        22 CFM        20. 5 CFM
                                        (0.56 M3/Min)  (0.56  M3/Min)
ZZ CFM         Z3  CFM,
(0.56 M3/Min)   (0.65 M^/Min)
    Particulate Mercury Concentra-
    tion (Expressed  as  Elemental Hg)   	0	

    Elemental Hg Vapor
    Concentration

    Organic Mercury Concentration
    (Expressed as Elemental Hg)
    Sampling Time


    Canister Sampling  Rate


    Vapor Analysis Rate

    Analytical Interval

    Material  Balance

i-   Added Contaminants /Concentration  NO gas
i
H
O
___0---
6. 1 y6tg /M
0^*5 Mm O /\J[
• ซ"'••'' Af ft / *vi
1,015 Min.
5.02 CFM
(24. 0%)
2 1pm
3. 0 Min.
87. 5%
NO gas
(I. 6 nnm^
---0---
8.4 yUg/M3
067 4. or /M"
• " ' WCA B ' *
1,015 Min.
5.02 CFM
(24. 0%)
2 1pm
3. 0 Min.
70. 0%
SOz gas
11. 7 nnm^
..-0---
8. 0 yUg/M
1 Q ปm a /T\A
' jvL5 ' "^
947 Min.
4. 86 CFM
(22.1%)
2 1pm
3. 0 Min.
53. 5%
H_S gas
ITT. "5 T-mml
---0---
4. 1 x 10"2
1, 540 Min.
4. 74 CFM
(20.6%)
82 1pm
6. 0 Min.
98. 8%
	
                                                                              (I)  Interference  Test
                                                                              (A) Ambient Air  Test

-------
 2. 9. 2  Ambient Air Monitoring  for  Elemental Mercury

           As a check  of the performance  of the method of mercury

 collection and analysis utilizing  the  canisters  and accessories as

 developed during the contract, an ambient air test for elemental

 mercury was carried  out from the roof of the Pomona Laboratory.

           The apparatus was set up  as previously described

 (Section 2. 5 and  2. 7).  The air  sample from out-of-doors was ducted

 through a three inch (i. d.) flexible  stainless  sttel tube to the mani-

 fold at the top  of the  Hi-Vol Sampler.   The GEOMET Model 103 was

 connected,  as previously,  to the exhaust from the plenum section of

 the Hi-Vol assembly.

          The ambient  air test was  carried out  for  25 hours and

 40 minutes (1540  minutes)  with 180g  of Ag./Al203 pellets  in the canis-

 ter used  for elemental mercury  collection.  The pellets utilized  were

 those which  had proved superior in previous testing,  Harshaw alumina

 Grade A1-0104T impregnated with 12%  silver.   The preparational  method

has been  described in  Secbion 2.6.3.   The  GEOMET Model 103  was

 operated  on  a 6-minute cycle with 257  analyses  automatically  obtained

 and printed during the  course of  the  experiment.   The following table

 shows the conditions and the Model 103 results.


                            Conditions

          Test Duration                         1540 min.
          Hi-Vol  Sampling  Rate                 651 1pm
          Canister Sampling Rate                134 1pm  (20.6% of total)
          Model 103  Sampling Rate              82 1pm
                                2-106

-------
                   Test Results from GEOMET Model 103


          Number  of Analyses                   257     .
          High Hourly  Value (10 analyses/hr)    145  ng/m  -hr.
          Low Hourly Value (10 analyses/hr)     12  ng/m^-hr.
          Average  Value (25+ hours)            41  ng/m^
          Tables 2-3 and 2-4 show  the individual  results obtained

with the Model  103; Figure 2-42  shows the applicable  calibration.

          After  mixing by rolling and quartering methods,  the 180 g

canister sample of pellets was separated into  ten  batches of 18 g of

pellets  each.   These were analyzed  by the techniques indicated  in

Section 2.8.3.  In  general,  a 5.0 ml aliquot of the 45 ml iodine

monochloride absorbent was  used in the reduction  step.   The  results

were obtained by use  of  a Perkin-Elmer -Model 303 atomic adsorption

spectrophotometer.   Calibration  of this  instrument is  shown in

Figure  2-43.
                               2-107

-------
         000004'4
         0 U 0 0 0 4 5
         0000046
         0000048
         0000047
         0000052
         0000055
         0 U 0 0 0 5 4
         0000048
         0 0 0 0 C 5_6_
         0 0 0 C C 5 6
         0000051
         0000053
         0000059
         0000059
         0000074
         0 0 0 0 0 8 6
Time 2015 Hours,  2/26/73
         0000
         0000
         0000
         0000
         0000
         0000
         0000
         0000224
         000023 1
         000023 1
         0000255
         0000252
         0 0 0 0 2J5
         0 0 0 0 2*8 2
         0000284
         0000284
         00003 1 1
         0000303
         0000304
         00003 1 1
         0000335
         0000378
         0000 185
1 1
1 1
3,
3*5
63
89
89
    Numbers in right hand
    margin are averages
    of DVM readings for
    ten previous  printouts.
Time 1615 Hours, 2/26/73
                    Table 2-3

          Analysis on Ambient Air Test
           GEOMET  Model 103
        Air Sampling Rate 82 1/m
Read Results Upward from Bottom to  Top

                     2-108

-------
•j u o o j > y
0000039
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0 000040
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0 0 C 0 0 4 3
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0000046
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0000049
0 U 0 0 0 4 6
0000033
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000004 2
                  Time 0051 Hours,  2/27/73
                  Time 2015 Hours,  2/26/73
2-109

-------
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34
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35
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34
34
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35
34
36
36
29
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            Time 0509 Hours, 2/27/73
   If
             Time 0051 Hours,  2/27/73
2-110

-------
0000035
0000032
0000029
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0 0 0 0 0 2^5_
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0 0 0 0 0 2 6
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                Time 0945 Hours,  2/27/73
   •v
                Time 0509 Hours,  2/27/73
2-111

-------
 0000209
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 0000223
 0000223
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                  Time 1357 Hours 2/27/73
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     -v
                  Time 0945 Hours, 2/27/73
         2-112

-------
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                Time 1755 Hours, 2/27/73
               1
               Time 1357 Hours,  2/27/73
2-113

-------
                             Table 2-4
                         Atmospheric  Test   .,,
                     GEOMET Model 103  Data"
                     Started 1615 hrs.,  2/26/73
R eading
(DVM divs)
298
215
79
50
43
39
37
38
35
35
37
34
34
32
33
27
31
34
77
154
Analysis
(ng/m3)
145
99
33
20
18
16
15
16
15
15
15
15
15
14
14
12
14
15
32
67
Time
(hrs. , midpoint)
1645
1745
1845
1945
2045
2145
2245
2345
0045 (2/27)
0145
0245
0345
0445
0545
0645
0745
0845
0945
1045
1145
*Each  reading represents an average of 10 readings.
                               2-114

-------
                           Table 2-4 (Con't.)
Reading
(DVM divs)

214

206

182

159

148

112  (7 readings)
Analysis
(ng/m3)
    99

    94

    82

    70

    64

    48
Time
(hrs., midpoint)

     1245

     1345

     1445

     1545

     1645

     1706
                                2-115

-------
     DVM Units
     500
                     :t
          llHIMn&i-miiii

     400

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2-117

-------
          The  results for the ten portions of the  adsorbent are



shown in  Table 2-5. As  is  apparent from  the  average air concentra-



tions  calculated from both  methods  and the total amounts of mercury



as analyzed by both  methods, the High-Vol canister procedure and



the GEOMET  103,  closely  correspond.  The  canister procedure showed


                                     +           3
an average air concentration of 40. 9 -  10.5  ng/m .   A simple stan-



dard  deviation cannot be calculated  for  the GEOMET data since the



concentration  of mercury in the  air  sample  changes with time.



          However, the standard deviation associated  with  the ten



determinations of the canister  sample  indicates a need for improve-



ment.   The 25.6% standard deviation indicates that  mixing and samp-



ling of the 180 g adsorbent bed has  not been adequately achieved.   Two



alternatives seem  appropriate:   (1)  the  adsorbent  bed size should  be



reduced so that (2) a relatively large fraction (or all) of the adsorb-



ent may be used in the recovery analysis.   As a third choice a more



rigorous procedure for  mixing  the solid sample may  be instituted.



However since a very large fraction of the total mercury is retained



at the top of the adsorbent,  particles from the first layer will always



have  a disproportionate effect on an  analysis.  Thus,  it would be  pre-



ferable to analyze  the entire adsorbent sample
                              2-118

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                            Table 2-5



              Ambient Air Test, Canister  Method.



              Analysis of Silver/Alumina Adsorbent
Sample No. Total Hg Collected
(ng)
1 1260
2 720
3 783
756 Average
3 Replicate 729
4 567
585 Average
4 Replicate 603
5 666
6 810
7 1008
8 945
9 774
10 927
Total 8451 nanograms
Average 845
Deviations
(ng)
415
125
62
116
278
242
179
35
163
100
71
82
1868
186.8
(a.d.)(22%)
       Air Sampled           206.4 m

                                       3  +               3
Average-Air  Concentration    40.9 ng/m   - 10.5 (o~) ng/m



Standard Deviation of  Total   216  (25. 6%)



 Mean Deviation of Total    187  (22.1%)
                              2-119

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          Section  3. 0

 CONCLUSIONS,  RECOMMENDATIONS
AND COMMERCIAL PRICE ESTIMATES

-------
                             Section 3. 0
                CONCLUSIONS, RECOMMENDATIONS
               AND COMMERCIAL PRICE  ESTIMATES
 3.1  SUMMARY
          During the course of the program a prototype device for
 the quantitative  collection of airborne mercury in particulate,  elemen-
 tal and combined forms,  respectively,  was designed,  fabricated and
 tested.  The device utilized a Hi-Vol  Sampler into which two  canisters
 containing absorbers for  elemental and combined mercury were added
 in a collection plenum below the glass fiber filter.   The plenum was
 located between  the funnel-shaped  inlet duct of the  Hi-Vol  Sampler and
 the blower  motor.   It supports the two collection  canisters and controls
 the air flow through the series arrangement.   Of the total air (20+ CFM),
 about  1/5 passes through  the  canisters.
          Particulate collection was tested with mercuric oxide and sul-
 fide on the glass fiber filter;  elemental mercury vapor was collected
 on a  silver-alumina adsorbent; dimethyl mercury was  collected on the
 activated  charcoal phase.
          As evaluated, the preferred  configuration of  the first canis-
 ter contained 180 g (160 ml) of 12% silver on  alumina  (Harshaw, A1-0104T)
 in a 1. 56"  (i. d.) x  5.5" cyclinder.   This  adsorber  removed 99.9+% of
 the elemental mercury passed through in  air samples.   The second can-
 ister  (same  dimensions) utilized  75 g (160 ml)  of activated charcoal
 (Barnebey-Cheney,  TCA grade).   It  removed  all combined mercury
from  the gas streams.  Other absorbents  and configurations were also
 examined.

                                3-1

-------
          The  absorbents were performance tested  in  24-hour runs
                                               3
at challenge levels  from ambient to 118 y*cg/m .  In addition, tests

were carried out in the presence of gaseous  pollutants:   hydrogen

sulfide,  sulfur  dioxide, chlorophenol,  nitric oxide  and xylene.   None

of the pollutants modified the  quantitative collection performance of

the absorbents.

          As designed, the  prototype canisters are made of PVC pipe.

Each is  closed by a stainless  screen held in  place by a Lucite fitting

which is also used to stack the canisters.  An aluminum plenum

houses the  added assembly.   The  collection canisters  may be emptied

directly  into a  Pyrex  shipping  container  or  each canister may be

enclosed in  a  sealed  polyethylene  shipping  container and returned to a

central laboratory for analysis and  refilling.   Tests  have  shown stable

retention of mercury and its compounds  by  the absorbents for periods

up to  six weeks.

          Particulate samples  are stored by  carefully folding the glass

fiber particle filter  and enclosing it in a polyethylene container for

mailing  and storage.

          An analytical procedure for  each of the three  separately  col-

lected forms of mercury has  been developed and tested.  In principle,

it involves  desorbing the collected sample into iodine  monochloride

solution  by application of heat  to the sample;  reduction  of  an aliquot

of the IC1 solution;  collection  of the resultant elemental  mercury on

gold wire; heating the gold wire by  an  induction furnace to desorb the

concentrated mercury into  a flameless atomic absorption spectrophoto-
                                 3-2

-------
meter cell;  and measurement of  the desorbed mercury  by standard




AAS light  absorption techniques at  253. 7 nm.   A number  of  variations



of the method are possible.



          Data  have been enclosed to support  all claims.  A proto-




type device  was also developed for the sample transfer operation.




The latter consists  of a crucible furnace and  furnace insert  to  trans-



fer the mercury-containing gases to IC1 bubblers.




          Detailed designs  (drawings) of all developed parts  are



included.




          On 21 February,  a demonstration of the operation  of the



collection  device was conducted before  the  Project Officer in the



Pomona  laboratory.






3.2  RECOMMENDATIONS




          Recommendations to  improve the field utility,  convenience



and operating costs  include the following:




          (1) It  would be highly desirable to reduce the volume,



weight and potential  cost  of the PVC canisters  and the  absorbents



contained in  each.   Two approaches to resolution  of  this need might



be conceived:   (a) the volume of  adsorbents may be  reduced  by



careful determination and specification  of the absorption capacity




requirement, air sample  volume requirements,  sampling time and



collection efficiency  requirements; (b)  two  canister sizes might  be



developed for industrial monitoring;  a  second for ambient  determina-




tions,   A series  of  interacting technical factors are involved in size



reduction including the efficiency  and composition  of  the adsorbents



and the factors  indicated  above.




                               3-3

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          Ancillary advantages  to decrease in canister size include




reduction of the size of the  plenum,  improved ease in shipping,




increased convenience and precision in sample analysis,  etc.




          (2)  Cost reductions may be achieved by development  of a




less expensive  adsorbent than the  currently utilized 12%  silver on




alumina.   It is anticipated that reduction in silver content might



be achieved by definition of  adsorption  capacity,  efficiency factors



and operating time so that a lesser safety margin than utilized in




the current adsorbent is  specified.   Also,  new adsorbents may also




be employed.



          (3)  Operational expense may  be  considerably decreased  by



development of methods for  quantitatively  regenerating the adsorbents.




          (4)  An area where  considerable, simplification in the  anal-




ytical  method might be gained is related to recovery  and extraction



of mercury - containing materials and  transfer into iodine mono-



chloride solutions.   Currently this  transfer is achieved by heating



samples of  absorbents  in a furnace while  simultaneously drawing air




through the furnace into IC1 bubblers.   This procedure  works well



enough,  but direct  extraction of each sample into liquid offers  con-



siderable simplification.  Initial tests with the particulate filter and




silver  on alumina  adsorbent  indicate that both these two  samples



appear tractable by liquid extraction.   Use  of sonicators or  auto-



matic  shakers appears useful in assisting  in achievement of  satis-



factory recovery  results.



          This  procedure would reduce the amount of  labor involved




in each analysis,  eliminate problems associated with  manipulations





                                3-4

-------
in a heated furnace, and potentially increase the precision of the

sample transfer process.


3.3   COMMERCIAL PRICE ESTIMATES

          For  purposes  of reference  only, the following estimates of

commercial  sale  prices  for  the  components  and services developed

under this project have  been estimated.  These price estimates

include standard  commercial profit margins and are subject to

change for volume  sales  and, of course,  in  the  event  of technical

improvements  and simplifications.
                                                        Estimated
                 Material                             Market Price

                 (a)  Collection Assembly:               $145.00
          Designed for  use with  standard.Hi-Vol
          Air Samplers.   Includes stainless
          steel  plenum,  canister  holder, criti-
          cal orifice and air  flow controls  but
          without canisters or pressure gage;
          complete with directions for use.
                 (b)  Elemental Mercury Col-           $ 49. 50
          lection  Canisters:   Filled with 180 grams
          of 10% silver on 1/8" alumina adsorbent
          pellets.
                 (c)  Combined Mercury Collection      $ 22. 50
          Canisters:   Filled with 85 grams  of 6-10
          mesh activated charcoal.
                 (d)  Particulate  Collection Filters:      $ 21. 50
          Glass Fiber Filters,  8 x 10 inches,  for
          use with standard Hi-Vol samplers.   In
          packages of 100 sheets.
                                 3-5

-------
                                                        Estimated
                 Material                           Market Price
                 (e)  Shipping  Containers:               $  7.50  per dozen
          Wide  mouth  Nalgene bottles  with
          screw caps,  48 mm opening.   For
          shipment of  canisters  or folded
          filters after  presealing in plastic
          envelopes  (not included).
          Analyses:

                 (a)  Certified  analysis,  refilling        $35.00
          and return  of Elemental Mercury
          Canisters
                 (b) Certified  analysis,                 $ 30. 00
          refilling and return  of  Combined
          Mercury  Canisters.
                 (c) Certified  analysis  of               $ 22. 50
          Particulate Samples  on 8 x 10 inch
          glass fiber filters.
These estimates are presented for reference and  should be utilized

as the bases  for measurement  of  improvements.
                               3-6

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              Section  4.0




EQUIPMENT DEVELOPMENT TABULATION

-------
                             Section  4.0




            EQUIPMENT  DEVELOPMENT  TABULATION






          The  equipment developed under this contract consists of



elements  of the test system,  preliminary and Prototype  collection




plenums,  Prototype canisters and segments of the GEOMET mer-



cury  recovery and analysis.




          The  following tabulation, Table 4-1, lists these items




along with their type,  source and referenced  drawings contained



within the text of  this  report.
                               4-1

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                                                        Table 4-1

                                          EQUIPMENT  TABULATION  SHEET
         Item
   1.   High-Volume  Air Sampler
       with Shelter  (1 each).
                                      Type
Unico  550 Turbine Jet;
with Wooden  Shelter.
                                                                          Source
Environmental Science
Div. ,  Bendix Corp.
                                                                                                   Reference Section
                                                                                                        2.3
   2.   Collection Plenum,  Test.
       (1 each)
GEOMET; with Probe  for
Mercury Challenge
Monitoring.
                                                                       GEOMET,  Inc.
                                                                  2.5,  2.7.2
   3.   Collection Plenum,  Proto-
       type configuration (1  each).
GEOMET; with Critical
Orifice for Monitoring
Canister  Through-put Air
Velocity.
                                                                       GEOMET,  Inc.
                                                                  Z.I.2
   4.   Dilution Air System
        (1 each).
 GEOMET; Includes Flow-
 meters,  Air Filter Canis-
 ter,  MAGNEHELIC Gage,
 and Air Pump.
GEOMET,  Inc. ; Dwyer
Instruments Inc. ;
Thomas Industries,  Inc.
                                                                                                         2.5
       Prototype Absorbent
       Canisters (6  each).
 GEOMET;  PVC plastic.
                                                                       GEOMET, Inc.
                                                                  2.7. 3
to
       Prototype Canister
       Closures (12 each)
 GEOMET;  LUCITE plas-
 tic and Stainless  Steel
 Screen.
                                                                       GEOMET, Inc.
                                                                  2.7. 3

-------
OJ
                                                       Table 4-1 (Con't. )
                                           EQUIPMENT TABULATION SHEET
     Item
Type
    Source
Reference Section
7.   Crucible Furnace
     (1 each).
Lindberg  HEVI-DUTY,
Type  56312-A.
Lindberg  Division,
(SOLA Industries)
    2.7.4
8.   Furnace  Insert
     (1 each)
GEOMET;  with two (2)
interchangeable Nickel
Alloy Crucibles.
GEOMET; Van Waters
and Rogers Co.
    2. 7.4

-------