SEPA
United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-80-203 Mar. 1981
Project Summary
Metal Particulate Emissions
from Stationary Sources
Volume 2. Characterization of
Collection Filters
The literature on filtration theory
and past experimental work was
reviewed and critiqued with regard to
the needs of EPA relative to stationary
source sampling. A laboratory evalua-
tion of aerosol collection efficiency
and flow resistance of filters potential-
ly useful in EPA sampling programs
was designed with respect to several
variables, including particle size
(0.05,~0.1 and 0.5 um mass median
diameter - MMD); gas velocity (4,12.
30, 83 and 126 cm/sec); and aerosol
composition and density (g/cm3) -
dioctyl phthalate (OOP) 1.0, sodium
chloride (NaCI) 2.17, beryllium sulfate
(BeSO4 2H2O) 2.36, lead nitrate
[(Pb(NO3)2] 4.53, and cadmium iodide
(Cdl2) 5.67. Filter collection
efficiencies were measured for the
various evaluation parameters with a
DOP penetrometer or sodium flame
photometer. With two exceptions,
collection efficiencies of greater than
99 percent were obtained for all filters
and test conditions. The exceptions,
tested with 0.3 um MMD NaCI
aerosol, were Millipore Mitex and
Whatman 41 filters, with collection
efficiencies of 75 to 50 percent,
respectively. The other membrane
filters (Millipore AA and Fluoropore)
exhibited high flow resistance at 30
and 83 cm/sec and could not be
tested at higher flow rates.
This Project Summary was devel-
oped by EPA's Environmental Sciences
Research Laboratory, Research
Triangle Park. NC. to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The objective of this phase of work
under EPA Contract No. 68-02-1219, is
to identify filter media having
acceptable properties for the efficient
collection of particles containing
potentially hazardous metals for the
following range of conditions
encountered in stack sampling:
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Variable
Particle size
Gas velocity
Particle composition and
density (g/cm3)
Temperature
Electrostatic charge
Aerosol concentration and
filter loading
Gas pressure and composition
Gas humidity
0.05, 0.1-0.2 and 0.5 /jm MMD
4, 12, 30, 83 and 126 cm/sec
OOP (1.0), NaCI (2.17),
(2.36), PbN03 (4.53) and Cdl2 (5.67)
Pretreatment at 500°C (effects of high
temperature exposure is measured rather
than efficiency at high temperature)
Not evaluated (aerosol charge neutralized)
Not to be varied. Convenient concentrations
and clean filters will be used.
Not to be varied. Ambient air will be used.
Not to be varied. Dry air will be used.
This report also presents a review of
the following filter characteristics to aid
in the selection of the most promising
type for stack sampling:
Media
Composition
Type
Millipore AA
Millipore Fluoropore FA
Gelman Spectro Grade
(without silicone treatment)
Mine Safety Appliance Co.
1106BH
mixed cellulose ester
teflon-polypropylene
glass
glass
membrane (0.8
micron pore size)
membrane (1 micron
pore size)
fiber
fiber
Arthur D. Little/Balston
"Microquartz"
Millipore Mitex
Whatman 41
quartz
teflon
cellulose
fiber
membrane (10
micron pore size)
fiber
A collection efficiency of at least 99
percent for the hazardous metal
containing paniculate was deemed
adequate.
Conclusions
Several types of filters suitable for
stack sampling were evaluated for
aerosol collection efficiency and flow
resistance. From this work, the
following conclusions can be drawn:
Filter media including MSA 1106 BH,
Gelman Spectro Grade (without sili-
cone), Arthur D. Little/Balston
Microquartz, Millipore AA and
Millipore Fluoropore FA have
collection efficiencies greater than
99 percent for the following ranges
of conditions.
Aerosols: 0.3 ,um OOP and NaCI,
BeSCv4H2O, Cdl2 and Pb (N03)2.
Sizes: 0.03 to 1.3 /urn MMD with
geometric standard deviations of
1.4 to 1.9.
Flow rate: 12 to 125 cm/sec.
The membrane-type filters, Millipore
AA and Fluoropore FA, exhibited
high flow resistance at 30 and 83
cm/sec, respectively (i.e., 78 and
114 mm Hg) and could not be test(
at higher flows.
Within the limits of measuremer
sensitivity, there was no different
in efficiency for variations in aerosi
density (1.0 to 5.7 g/cm3) or size (0.
to 1.3 yum MMD).
Millipore Mitex membrane an
Whatman 41 cellulose fiber filtei
with efficiencies of 75 and 5
percent (for 0.03 /am NaCI) ar
unsuitable for stack samplin
applications.
In general, the filter media tested (e:
cepting Millipore Mitex and Whatma
41) have adequate collectio
efficiencies for the collection i
particles containing hazardous metal
Other factors (such as thermal stabili
and background levels of trac
elements) may influence filter selei
tion for a particular stack samplir
application.
Recommendations
Areas in which further work is recod
mended include the following:
Measure filter efficiencies for
selected particulate challenj
sample as a function of prior filt
loading, aerosol charge and g<
humidity.
Measure the utility of organic men
brane filters at temperatures of 121
150°C for times up to two hours,
simulation of stationary soure
sampling. For example, the test filti
could be backed up by a quartz filti
maintained at ambient temperatur
nitric acid digestion and atom
absorption spectrophotometr
analysis of the metal component i
the particulate challenge for the tw
filters would provide a measure i
efficiency.
Carry out efficiency measuremen
for trace levels of hazardous met
particulate (10-100 A*g/m3) in tl-
presence of typical levels <
particulate emissions froi
stationary sources (20-200 mg/m
to determine if there is a preferenti.
penetration of hazardous met
particulate during particulal
sampling.
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Screen candidate filters for their
suitability in carrying out trace
hazardous metals analysis by various
analytical methods, including x-ray
fluorescent analysis and atomic
absorption spectrophotometry.
This Project Summary was authoredbythe Staff of the Center for Environmental
Research Information. USEPA, Cincinnati, OH 45268.
Roy L. Bennett is the EPA Project Officer (see below).
The complete report, entitled "Metal Paniculate Emissions from Stationary
Sources: Volume 2. Characterization of Collection Filters," (Order No.
PB 81-121 154; Cost: $8.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
> U.S GOVERNMENT PRINTING OFFICE: 1961-757-012/7007
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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