EPA-R2-73-141
FEBRUARY 1973 Environmental Protection Technology Series
Kraft Effluent
Color Characterization
Before and After
Stoichiometric Lime Treatment
.^°S7%
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
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EPA-R2-73-141
February 1973
KRAFT EFFLUENT COLOR CHARACTERIZATION BEFORE AND
AFTER STOICHIOMETRIC LIME TREATMENT
By
John W. Swanson
Hardev S. Dugal
Marion A. Buchanan
Edgar E. Dickey
Project 12040 DKD
Project Officer
George Webster
Office of Water Programs
Environmental Protection Agency
Washington, D.C. 20460
Prepared for
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
For sale by the Superintendent of Documents, XT.S. Government Printing Office, Washington, D.C. 20402
Price $1 domestic postpaid or 75 cents QPO Bookstore
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and 'apprpved for publication.
Approval does/not. si-gnify that the ,esontents neces-
sarily reflect -the, views -and .policies of the
Environmental Protection, Agency, nor does mention
of trade names, or commercial products constitute
endorsement .or recommendation for use.
il'
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ABSTRACT
The lime-treatment process was found to remove on an average about 86
percent of the color, 57 percent of the total organic carbon, and 17
percent of total sugars from the waste effluent during the period of
approximately 15 months over which the samples were collected. No appre-
ciable change in chloride content was noticed.
The "weight average" molecular weights (M^) of the untreated acid-insol-
uble fractions varied from < UOO to 30,000 and of the untreated acid-
soluble, lime-treated acid-insoluble, and lime-treated acid-soluble
fractions from < ^-00 to 5000.
The study shows that, color bodies having an apparent M^ of < hQQ are not
removed by lime treatment and those having M^ of 5000 and above are com-
pletely removed. The intermediate range of M^ ^00 to 5000 apparently
undergoes partial removal.
Infrared spectroscopy data indicate that the acid-insoluble color bodies
(high My) contain a high proportion of conjugated carbonyl groups where
conjugation with an aromatic ring is probable. The acid-soluble fractions
(low M^) seem to contain nonconjugated carboxyl groups and may be assoc-
iated with carbohydrate material. However, color bodies are found to be
aromatic in nature (partially degraded lignin), possess a negative charge,
and exist primarily as soluble sodium salts in aqueous solutions.
The color bodies which are not removed by lime treatment have low M^., high
nonconjugated carboxyl groups, some ligninlike character, and seem to.be
associated with colorless carbon compounds.
This report was submitted in fulfillment of Contract Ho. 120^0 PKD under
the partial sponsorship of the Office of Research and Monitoring,
Environmental Protection Agency.
iii
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CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
III Introduction 5
IV Initial Characterization and Handling of
Colored Wastes 7
V Isolation and Fractionation of Color Bodies 21
VI Characterization of Color Bodies 35
VII Experimental 59
VIII Acknowledgments °7
IX References ^9
X Publications 71
XI Appendices 73
XII WRIC Abstract Form 77
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FIGURES
Page
1 CORRELATION OF SOLIDS CONCENTRATION WITH ABSORBANCE
(AT 1*20 nm) OF UNTREATED WASTE 12
2 EFFECT OF pH ON ABSORBANCE (AT 1*20 nm) OF UNTREATED WASTE 13
3 EFFECT OF STORAGE ON ABSORBANCE (AT pH 7.6) OF UNTREATED
WASTE
lU
1* CORRELATION OF TOTAL ORGANIC CARBON WITH COLOR UNITS
(AT pH 7.6) OF FREEZE-DRIED UNTREATED, LIME-TREATED,
AND RETURNED WASTES 19
5 CORRELATION OF ABSORBANCE (AT 251* nm) WITH COLOR UNITS
(AT pH 7.6) OF FREEZE-DRIED UNTREATED, LIME-TREATED,
AND RETURNED WASTES. 20
6 CORRELATION OF TOTAL ORGANIC CARBON WITH ABSORBANCE
(AT 251* nm) OF FREEZE-DRIED UNTREATED, LIME-TREATED,
AND RETURNED WASTES 2U
.7 FRACTIONATION OF UNTREATED DILUTE KRAFT MILL DECKER
WASTE. PARAMETER CALCULATED AS PERCENT OF UNTREATED
WASTE PRESENT IN ONE ML OF THE COLLECTED FRACTION 25
8 FRACTIONATION OF LIME-TREATED DILUTE KRAFT MILL
DECKER WASTE. PARAMETER CALCULATED AS PERCENT OF
LIME-TREATED WASTE PRESENT IN ONE ML OF THE
COLLECTED FRACTION 26
9 FRACTIONATION OF UNTREATED AND LIME-TREATED DILUTE
KRAFT MILL WASTES. RATIO OF COLOR UNITS TO
VOLATILES x 103 VERSUS ELUTION VOLUME 33
10 FRACTIONATION OF ACID-INSOLUBLE COLOR BODIES. COLOR
UNITS CALCULATED AS PERCENT OF UNTREATED WASTE
PRESENT IN ONE ML OF THE COLLECTED FRACTION 33
11 FRACTIONATION OF ACID-INSOLUBLE COLOR BODIES. TOC
CALCULATED AS PERCENT OF UNTREATED WASTE PRESENT
IN ONE ML OF THE COLLECTED FRACTION 31*
12 FRACTIONATION OF ACID-SOLUBLE COLOR BODIES. COLOR
UNITS CALCULATED AS PERCENT OF UNTREATED WASTE
PRESENT IN ONE ML OF THE COLLECTED FRACTION 31*
vi
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Page
13 FRACTIONATION OF ACID-SOLUBLE COLOR BODIES. TOG
CALCULATED AS PERCENT OF UNTREATED WASTE PRESENT
IN ONE ML OF THE COLLECTED FRACTION 3k
lb ABSORPTIVITY VERSUS WAVELENGTH (VISIBLE RANGE) OF
INDULIN "A," ACID-INSOLUBLE AND ACID-SOLUBLE COLOR
BODIES OF UNTREATED AND LIME-TREATED - KRAFT MILL
DECKER WASTES UO
15 ABSORPTIVITY VERSUS WAVELENGTH (ULTRAVIOLET RANGE) OF
INDULIN "A," ACID-INSOLUBLE AND ACID-SOLUBLE COLOR
BODIES OF UNTREATED AND LIME-TREATED KRAFT MILL
DECKER WASTES ^1
16 INFRARED SPECTRA OF KRAFT MELL DECKER EFFLUENT COLOR
BODIES k3
IT MOLECULAR WEIGHT RANGES AND DISTRIBUTION OF FRACTIONATED,
UNTREATED ACID- INSOLUBLE COLOR BODIES ^9
18 MOLECULAR WEIGHT RANGES AND DISTRIBUTION OF FRACTIONATED,
LIME- TREATED ACID- INSOLUBLE COLOR BODIES 50
19 MOLECULAR WEIGHT RANGES AND DISTRIBUTION OF FRACTIONATED,
UNTREATED ACID-SOLUBLE COLOR BODIES 51
20 MOLECULAR WEIGHT RANGES AND DISTRIBUTION OF FRACTIONATED,
LIME-TREATED ACID-SOLUBLE COLOR BODIES 52
21 WEIGHT AVERAGE MOLECULAR WEIGHT (M^) DISTRIBUTION OF
FRACTIONATED ACID- INSOLUBLE COLOR BODIES 53
22 WEIGHT AVERAGE MOLECULAR WEIGHT (M^) DISTRIBUTION OF
FRACTIONATED ACID-SOLUBLE COLOR BODIES 5^
23 WEIGHT AVERAGE MOLECULAR WEIGHT (M^) OF ACID-INSOLUBLE
COLOR BODIES VERSUS THE DEGREE OF REMOVAL BY LIME 55
TREATMENT
2k WEIGHT AVERAGE MOLECULAR WEIGHT (M^) OF ACID-SOLUBLE
COLOR BODIES VERSUS THE DEGREE OF REMOVAL BY LIME 55
TREATMENT
25 PYROLYSIS GAS CHROMATOGRAMS OF FRACTIONATED COLOR
BODIES FROM THE KRAFT MILL DECKER EFFLUENTS 58
26 DIAGRAM OF GEL PERMEATION CHROMATOGRAPHY APPARATUS 6k
vii
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TABLES
Ko. Page
1 Analytical Data on Kraft linerboard Untreated Decker
Waste Water °
2 Analytical Data on Kraft Linerboard lime-Treated
Decker Waste Water °
3 Analytical Data on Returned Waste Water from Lime-
Organic-Sludge Holding Ponds -1-0
U Analytical Data on Freeze-Dried Color Bodies from
Untreated Waste Water -*-"
5 Analytical Data on Freeze-Dried Color Bodies from
Lime-Treated Waste Water ^7
6 Analytical Data on Freeze-Dried Color Bodies from
Returned Waste Water ^-°
7 Effect of Lime Treatment on Waste Fractions 27
8 Analysis of Fractionated Color Bodies ^8
9 Percentage of Yield and Removal by Lime of Untreated
and Lime-Treated Waste Fractions ^9
10 Fractionation of Aci d- Insoluble Color Bodies by Column
Chr omat o gr aphy 31
11 Fractionation of Acid-Soluble Color Bodies by Column
op
Chromatography -^
12 Comparison of Acid- Insoluble and Acid-Soluble Fractions
with Indulin 36
13 Analytical Data on Fractionated Acid-Insoluble Color
Bodies from Untreated Waste 38
lU Sugar Analyses of Untreated and lime-Treated Wastes 39
15 Relative Mobilities of Color Bodies by Gel
Electrophoresis 57
viii
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SECTION I
CONCLUSIONS
Conclusions are divided into tvo categories: Observations and Major Con-
clusions .
Observations
Eight series of composite unbleached kraft mill waste samples were ship-
ped from Riceboro, Georgia to Appleton, Wisconsin. Analysis of these
samples before and after shipment (lapse time 3-U days) shoved that no
appreciable changes occurred in color, total solids, fixed solids (.ash),
and volatile content during shipment.
Visible spectra were recorded on a series of four dilutions of the un-
treated waste samples. The pH was adjusted to 1.6 in each case. The
decrease in absorbance values with dilution was found to be linear,
demonstrating that the Beer-Lambert law was being observed in the visible
region. This suggests that a direct correlation between absorbance and
concentration exists.
Freeze-dry ing of color bodies was carried out. No significant changes
in color, absorbance, and total organic carbon (TOC) were noticed on
samples before and after freeze-drying. However, freeze-dried color
bodies from the lime-treated wastes showed an average decrease of if5
percent in their sedimentation coefficient values indicating a decrease
in molecular weight or an increase in hydration of the sedimenting mole-
cules . Upon redissolution of the freeze-dried color bodies, an opaque
colorless sediment was noticed which had to be removed before sedimenta-
tion coefficient measurements were conducted. This sediment was found
to be mainly silica and some starch. It is possible that loss of these
materials from the colored solutions resulted in lower sedimentation co-
efficients .
The carbonate content of the color bodies was found to increase during
processing, freeze-drying, and conditioning. This increase was found to
be due to the absorption of carbon dioxide from the atmosphere. The
freeze-dried color bodies were, therefore, conditioned to a constant
weight in air before storage.
A concentrated solution of freeze-dried color bodies could be acidified
to pH 1.0 to give acid-insoluble and acid-soluble components. The data
indicated that the combined color recoveries of the acid-insoluble and
acid-soluble components were 93 percent in the case of untreated waste
and 8l percent in the case of lime-treated wastes. The corresponding
TOC recoveries were 77 percent and 32 percent, respectively. Aqueous
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alkaline solutions of these materials could be further fractionated into
various molecular weight ranges on Bio-Gel columns.
Major Conclusions
1. The lime treatment process on an average removed about 86 percent
color, 57 percent TOG, and 17 percent sugars, indicating that the
remaining ^3 percent TOC was responsible for only Ik percent of the
original color. Most of this TOC is. believed to be in the form of
carbohydrate degradation products, resin acids, fatty acids, etc.
2. The data also indicate that the acid-insoluble components of mill
wastes lost 9^.3 percent color and 9^ percent TOC, whereas acid-
soluble components lost only 7^-^ percent color and ^3-^ percent TOC
during the lime treatment.
3. Infrared spectroscopy shows that the acid-insoluble color bodies
(high My.) contain a high proportion of carbonyl groups (carboxyl,
ketone, or both) conjugated with an aromatic ring, whereas the
acid-soluble fractions (low My.) seem to contain nonconjugated car-
boxyl groups, and seem to be associated with carbohydrate material.
h. The "weight average" molecular weights (My.) of the untreated acid-
insoluble fractions varied from < ^00 to 30,000. and of the untreated
acid-soluble, lime-treated acid-insoluble, and limetreated acid-
soluble fractions from < kQO to 5000..
5. Color bodies having an apparent My. of < ^00 are not removed by'lime
treatment and those having My. of 5000. and above are completely re-
moved. The intermediate range of My. ifOO to 5000 apparently undergoes
partial removal.
6. Most of the color bodies are ligninlike in character and appear to
consist of lignins which have been degraded to various degrees.
7- In aqueous media color bodies are soluble as salts (especially sodium
salts). Decationization by cation exchange resin resulted in pre-
cipitation of color bodies.
8. Gel electrophoretic studies showed that all isolated color bodies are
negatively charged. Except a few color bodies, all others showed
mobilities higher than Indulin (alkali lignin), indicating a higher
density of negative charge per molecule.
9. The color bodies which are not removed by lime treatment have low
My, high nonconjugated carboxyl groups, some ligninlike character,
and seem to be associated with colorless carbon compounds (carbo-
hydrate material, rosin acids, etc.).
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SECTION II
RECOMMENDATIONS
On the basis of this study, the following recommendations are made.
1. Because the absorption of radiation by color bodies varies with pH
and time, the spectrophotometric studies must be performed at^ a
constant pH as soon as possible after sampling.
2. As it is pH dependent, the color of two different was.tes should be
compared at the same pH.
3. Freeze-dried color bodies must be conditioned in air to a constant
weight before storage to minimize weight fluctuations caused by
carbon dioxide absorption.
k. Preliminary studies, based upon the observation that color bodies
which are not removed by lime are of low molecular weights and con-
tain high nonconjugated carboxyl groups, have shown that multivalent
cations could be used with lime (before or after lime treatment) to
achieve over 99 percent color removal. An extensive study on the use
of such cations with lime is presently in progress at The Institute
of Paper Chemistry.
5. Color bodies which are not removed by lime are also found to be
associated with the carbohydrate material. In order to reduce the
negative effect, if any, of the carbohydrates on the efficiency of
lime treatment, the mill wastes should be passed through a biooxida-
tion stage before the addition of lime. It is proposed that such
work be carried out first in the laboratory.
6. A study on the effect of various degrees of pulping on molecular
weight of color bodies in mill effluents and their subsequent lime
treatment should be conducted.
7. It would be useful to obtain additional UV- and IR-spectra of
samples with considerably lower inorganic content. Tentative sug-
gestions regarding possible differences in relative amounts of
aromatic and aliphatic molecular units would be worthy of further
investigation using nuclear magnetic resonance (KMR) spectroscopy.
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SECTION III
INTRODUCTION
Recently, the pulp and paper industry has given major attention to the
effect of mill effluents on receiving water color and to the development
of means for reducing the discharge of colored organic material to such
waters. Major sources of color from the pulp mill are the caustic ex-
traction stage in bleaching, and the unbleached screening and decker
filtrates. It is believed that the colored material originates from
lignins and lignin derivatives which are washed out of the cooked pulp.
Since lignin is highly resistant to microbiological degradation, the
color passes through the biological treatment processes. The colored
effluents make the receiving waters brownish in color and reduce the
light penetration in water. This reduction in light intensity affects
aquatic plants by reducing photosynthesis and thereby adversely affects
the dissolved oxygen content of water.
The lime-treatment process developed by the National Council of The Pulp
and Paper Industry for Mr and Stream Improvement (NCASl) is reported to
be capable of removing about 90 percent of the color from both bleaching
and pulping effluents 5. This process has gone through the pilot^plant
stage and at present is being used by several mills.
Although the technology of lime treatment is well developed, conflicting
results have been reported with respect to the underlying chemistry of
the process. However, recent studies by Dence, et_a^.6 have shown that
the removal of colored material from spent caustic extraction liquor with
lime is a chemical rather than a physical process and that color removal
is dependent on (a) the presence of enolic and phenolic- hydroxyl groups,
and (b) on the molecular weight, of solids contained in the liquor. No
data on the molecular weight distribution were reported.
This report presents work done on the characterization of color bodies
before and after lime treatment of the decker wastes from the Interstate
Paper Corporation kraft linerboard mill at Riceboro, Georgia, The
general objective of the project was the isolation of the colored com-
ponents of the dilute kraft waste liquors before and after stoichiometric
lime treatment and their subsequent characterization. It is generally
known that such brown-colored materials are complex: mixtures of more-or-
less acidic polymers which are chemically sensitive. Such materials when
isolated frequently tend to condense further into intractable, amorphous
solids. Although the colored fractions, herein described, appeared to be
reasonably stable one must assume that each separation may have been ac-
companied by minor chemical changes, at least.
The project approach was divided into three major categories:
1. Initial Characterization and Handling of Colored Wastes.
2. Isolation and Fractionation of Color Bodies.
3. Characterization of Color Bodies.
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SECTION IV
INITIAL CHARACTERIZATION AND HANDLING OF COLORED WASTES
Sampling and Handling:
Twenty-four-hour composite samples of untreated decker waste (U-Series),
lime-treated waste containing color bodies that are not removed by lime
treatment (LT-Series), and returned waste containing supernatant from
sludge holding ponds and returned to the treatment process (R-Series),
were shipped by air from Riceboro, Georgia to Appleton, Wisconsin. The
samples were shipped in five-gallon polyethylene jugs enclosed in spe-
cially designed wooden crates provided by The Institute of Paper Chemistry-.
The usual transit time was two to three days. Samples in transit longer
than three days were discarded. Eight series of samples were received
over a period of 15 months in this manner. The R-Series were used for
purposes of comparison only.
Chemical Characterization
Upon receipt at the Institute, representative aliquots of the liquid
wastes were chemically analyzed and the data are given in Tables 1, 2S
and 3. A comparison of these data with that obtained before shipment
from Riceboro, Georgia, indicated that no appreciable changes in color,
total solids, fixed solids, and volatiles occurred during shipment of
the samples from Riceboro to Appleton under the sampling and shipping
conditions recommended by the Institute. Calculation from the data
showed that on an average about 86 percent color and 57 percent total
organic carbon are removed by the lime-treatment process under study.
Spectrophotometric Examination of Liquid Wastes
The ultraviolet and visible spectra of the waste samples of Series One
and Two were found to be similar and representative of other series.
The absorption characteristics of Series Two, discussed in the follow-
ing sections, may be considered to apply to all samples.
The spectra were recorded with a Beckman Model DK-2 ratio recording spec-
trophotometer, at the original pH and pH 7.6. Distilled water was used
as a reference for all of the samples. The following was observed.
Visible Spectra
a. All of the samples exhibited an increase in absorbance as the
wavelength decreased (750-350 nm).
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TABLE I
ANALYTICAL DATA ON KRAFT LHHRBOARD UNTREATED DICKER WASTE WATER
CD
Sample Designation
Month of Sampling
PR
Color Units
at original pH
at pH 7.6
Sodium, mg/1
Calcium, mg/1
Organic Nitrogen, mg/1
Organic Carbon, mg/1
Total Solids, mg/1
Fixed Solids (Ash), mg/1
Volatile s, mg/1
Carbonate, mg/1
Ul
Jan.
10.9
905
705
31*1
61
1360
920
1*1*0
_-
U2
March
11.6
380
1*66
132
125
1526
121*1
285
_-
U3
May
9.6
560
336
₯*
1.7
120
1212
898
311*
121
Ul*
Sept.
10.1
1100
800
372
2A
2.1*
200
15*
1070
1*70
J78.5
U5
Oct.
10.3
980
660
1*02
9.2
2.8
190
1600
1090
510
181«
U6
Dec.
10.3
1100
820
286
11*
195
131*0
893
10*7
132.5
U7
Jan.
H.2
2000
1200
1*1*3
16
355
2100
1320
780
256
U8
March
10.2
1*1*0
300
350
22
125
ll*50
ni*o
310
ito.5
Range
9.6-11.6
1*1*0-2000
300-1200
286-1*66
2 .1*-132
1.7-2.8
120-355
1212-2100
893-1320
310-780
121-256
Avg
10.5
1087
680
37^.5
28.0
2.3
186
1516
1073
1*1*3
172
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vo
Sample Designation
pH
Color Units
at original pH
at pH 7.6
Sodium, mg/1
Calcium, mg/1
Organic Nitrogen, mg/1
Organic Carbon, mg/i
Total Solids, mg/1
Fixed Solids (Ash), mg/1
Volatiles, mg/l
Carbonate, mg/1
TABLE! 2
ANALYTICAL DATA ON KRAFT LINERBOARD LIMB-TREATED DECKER WASTE WATER
LT1 LT2 LT3 LTl* LT5 LT6 LT7 LT8 Range Avg
12.1 12.3 12.1 12.2 12.2 12.2 12.5 12.2 12.1-12.5 12.2
250
105
306
1*88
2060
1630
1*30
w
90
U05
505
«»
60
2239
1827
1*12
MM
50
310
1*0
3.6
U5
1818
I*t20
398
171
360
160
1*11*
335
3.0
110
2080
3580
500
150
280
120
1*11
3l»0
2.1
90
1920
1560
360
82.5
280
120
26k
378
100
1790
1380
1*10
96.5
too
170
1*31*
1*07
-
120
2220
1730
U90
217.5
150
60
396
U56
-
1*5
2210
171*0
1*70
250
150-1*00
50-170
261*-l*3l*
335-505
2.1-3.6
U5-120
1790-2239
1380-1827
398-500
82.5-250
287
109
367.5
1*19
2.9
80
20U2
1608
1*31*
161.2
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TABLE 3
ANALYTICAL DATA ON. RETURNED WASTE WATER FROM LIME-ORGANIC SLUDGE HOLDING PONDS
H
o
Sample Designation
pH
Color Units
at original pH
at pH f.6
Sodium, mg/1
Calcium, mg/1
Organic Nitrogen, mg/1
Organic Carbon, mg/1
Total Solids, mg/1
Fixed Solids (Ash), mg/1
Volatiles, mg/1
Rl
11.6
855
660
62
-
ll*90
1060
1*30
R2
n.J*
580
500
3U
156
1577
1238
339
Rl*
U.5
520
320
368
0.8
1.5
103
1380
1090
290
R5
11.5
860
1*80
1*17
2.0
1.6
178
l6i*0
121*0
1*00
R7
11.6
860
500
520
1*
220
1900
11*70
1*30
R8
11.1*
900
520
578
<2
196
201*0
1560
1*80
Range
U.WX.6
520-900
320-660
368-578
1-62
1.5-1.6
103-220
13.80-20llO
1060-1560
290-1*80
Avg
11.5
779
501
1*75
17
1.6
171
1671
1276
395
Carbonate, mg/1
255
292
31*1*
390
255-390
320
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b. None of the samples contained an absorption maximum in this
region.
c. The -untreated waste and the returned waste (sludge pond super-
natant) gave comparable absorb an ce values.
d. The lime-treated waste exhibited lower absorption than the
other two samples through this region.
e. After adjusting the waste samples at pH 7.6 a general decrease
in absorbance was observed.
The visible spectra demonstrated that no single color is present in the
waste samples, rather they are mixtures of different colors as character-
ized by the increase in absorption as the wavelength decreases. In
addition, it was demonstrated that lime treatment decreases the amount
of color-giving materials .
Ultraviolet Spectra
a. The samples exhibited increased absorbance as the wavelength
decreased (350-230 nm).
b. The absorption patterns of untreated and returned wastes were
quite similar. Returned wastes gave higher absorption values.
c. Lime-treated waste gave the lowest absorption values.
The ultraviolet spectra indicated that the mill wastes contain materials
similar to those present in lignin and that the amount of these materials
decreases by lime treatment.
The effects of dilution, pH, and lime on absorbance were also studied.
Effect of Dilution on Absorbance at pH 7.6
Visible spectra were recorded on a series of four dilutions of the un-
treated sample. The pH was adjusted to "J.6 in each case.
The decreases in absorbance values with dilution were found to be linear
(Figure l), demonstrating that the Beer-Lambert law was being observed
in the visible region and suggests that a direct correlation between
absorbance and concentration exists.
Effect of pH on Absorbance at Constant Dilution
The pH of the untreated sample was varied between 11.0 and 2.0 in six
steps. The upper limit of 11.0 was set as this was the pH of most of
the original waste water samples. The lower limit of 2.0 was set be-
cause below this pH most of the color bodies became insoluble (slight
precipitation was noticed at all pH on the acid side). The points be-
tween pH 2.0 and 11.0 were chosen at random.
The absorbance data illustrated that the lowest pH value gave the lowest
absorbance value and that the absorbing materials (color producing) are
11
-------
E
c
O
CM
LU
| i
GO
cr
o
to
m
< 0 246 8 10 12 14
TOTAL SOLIDS CONCENTRATION x I02, g/l
Figure 1. Correlation of Solids Concentration with
Absorbance (at k2Q nm) of Untreated Waste
pH sensitive (Figure 2). As the pH increased, the absorbance values in-
creased until a pH of approximately 5 was obtained. Further pH increases
resulted in lowering of the absorbance values to a pH of approximately
7-8. Near this point, the absorbance values then increased with in-
creasing pH values. A duplicate run after 3 days showed the same trend.
The reason for the higher absorbance at pH 5.0 and after pH 8.0 was not
pursued as it falls out of the scope of this project. However, this may
be due to the ionization of different chromophores at different pH
values.
The rate of absorbance change per unit of pH change was found to be
greater at the lower wavelengths, because this is the region of more
intense absorption and is, therefore, more sensitive to small variations.
Effect of Time on Absorbance
Absorption spectra of the untreated sample at pH "J.6 were run after
storing the samples at room temperature for 1, 3, 6, and 2h days. All
samples exhibited an increase in absorbance as the wavelength decreased
(700 to 230 nm). Three wavelengths (U20, 280, and 25U nm) were chosen
for further study. Wavelength k20 nm was used because it is in the
high energy area in the visible spectrum and 280 nm was selected because
this is the standard area of absorption for lignin7. The reasons for
using 25U nm were circumstantial. Initial work at 25^ nm was done be-
cause this was the only continuous monitoring device at hand when this
work was started. However, a correlation between 25^ and 280 nm was
established, thus justifying continued use of 25^ nm' for monitoring
kraft mill effluents.
12
-------
o
(VI
LJ
O
Z
<
ffl
IT
O
(/>
GO
~-^7'
^
V **
I
I
I
I
0 2 4 6 8 10 12
pH OF UNTREATED SAMPLE AT CONSTANT DILUTION
Figoare 2. Effect of pH on Absorbance (at 1*20 nm)
of Untreated Waste
The absorbance values measured at the above 3 wavelengths (Figure 3) in-
creased up to a storage time of 3 days and then decreased, first sharply
between 3 and 6 days and then slowly between 6 and 2k days. The exact
reason for such a behavior is not known but it could be due to the possi-
bility that limited oxidation might tend to increase color.
The observations so far suggest that in order to be able to compare dif-
ferent wastes, the spectrophotometric study should be performed at the
same pH and that in case the. liquid wastes cannot be analyzed immediately
upon receipt, they should be stored in a state in which minimum possible
changes occur. The storage conditions are discussed in the following
text under waste storage.
Waste Storage
Reductions in color were observed during the storage of wastes in the
liquid form over longer periods, even at 5°C. Freeze drying of the
colored wastes was found to prevent appreciable changes in color bodies
during storage. Freeze-dried material was readily soluble in water.
It was thought that any appreciable physical change occurring in color
bodies during freeze drying could be detected by observing changes in
the sedimentation coefficient values of the color bodies before and
13
-------
40r-
LiJ
Z)
5
o
CO
cc
o
CO
CO
<
30
20
254 nm
280 nm
420 nm
I
8 12
TIME, DAYS
16
20
24
Figure 3.
Effect of Storage on Absorbance (at pH 7.6)
of Untreated Waste
after freeze drying. The sedimentation coefficient, defined as the
velocity of sedimenting molecule per unit field, is a function of the
anhydrous molecular weight of the sedimenting substance and the partial
specific volume of the solute. It .decreases with decrease in molecular
weight, and increases in hydration of the sedimenting molecule.
The sedimentation coefficients were determined according to the method
described by Schachman8 with the ultracentrifuge. The lapse time between
the measurements of samples before and after freeze-drying was about U-5
days. The results indicated that, although some variation occurred, the
untreated samples showed little average decrease in sedimentation values
due to the freeze-drying step, whereas the lime-treated samples showed
consistently an average decrease of over ^5 percent. Obviously, either
the molecular weight of the substance is decreasing or the size and
hydration of the molecule is increasing. Because no change in color and
TOG (before and after freeze-drying) was noticed, the reason for the de-
crease in sedimentation coefficients of the lime-treated samples was not
further investigated. It should be pointed out "here that, upon redissolu-
tion in water, the freeze-dried material gave an opaque colorless sediment
which upon emission spectrographic analysis was found to be mainly silica.
-------
Microscopic investigation tinder polarized light also showed the presence
of starch. It is possible that the loss of these materials from the
colored solutions resulted in lower sedimentation coefficients of the
freeze-dried color bodies.
The handling and freeze-drying of the wastes is explained in the experi-
mental part of this report. Chemical analysis of the freeze-dried color
bodies of all samples (untreated-, lime-treated-, and returned-Series)
are given in Tables U, 5, and 6. Calculations showed that no apprecia-
ble change in chloride content occurred during lime treatment. The
sludge obtained by centrifuging the original and carbonated colored
wastes was also freeze-dried and analyzed (data not included in this
report). These sludges were found to contain mainly fibers, calcium
carbonate, and very low amounts of sodium.
Analytical data on the freeze-dried color bodies did not show any partic-
ular trend. Fluctuations in the data were found to be due to carbon di-
oxide absorption during processing, freeze drying, and conditioning of
freeze-dried material. Data calculated on a carbon dioxide~free basis
showed lesser variations but still no particular trend was evident.
Aqueous solutions of freeze-dried color bodies were tested for color,
absorbance, and total organic carbon (TOG). The plots of color versus
organic carbon (Figure U), color versus absorbance at 251* nm (Figure 5)
and absorbance at 25^ nm versus organic carbon (Figure 6) gave linear
relationships. (The reasons for using 25*j- nm wavelength have already
been mentioned in this report.) Because no color losses were noticed
upon freeze drying nor upon longer storage periods in the dry- state, all
color bodies were, therefore, freeze-dried and stored until used for
further study.
15
-------
CT\
TABLE 1+
ANALYTICAL DATA ON FREEZE-DRIED COLOR BODIES FROM UNTREATED WASTE WATER
Sample Designation
Sodium, percent
Calcium, percent
Nitrogen, percent
Chloride, percent
Organic Carbon, percent
Total Solids, g/100 ml
Fixed Solids (Ash), percent
Volatiles, percent
Carbonate, percent
in Total Solids
in Fixed Solids
U2-1C
24.8
0.3
0.05
10.4
0.12
84.0
16
18.6
U3-1C
23.4
0.5
0-.07
10.9
0.09
78.3
21.7
6.4
9->*
U4-1C
24.4
0.1
0.1
0.5
16.6
o.n
74.3
25.7
16.4
25.1
U5-1C
25.4
0.2
0.06
0,7
17.4
0.11
78.3
21.7
16.6
23.1
u6-ic
24.0
0.1
0.82
18.1
0.09
73.7
26.3
11.4
17.2
U7-1C
23.8
0.1
0.6
19.6
0.17
69.1
30.9
12.5
24.6
U8-1C
28.8
0.2
**»
0.96
9.6
0.12
85.5
14.5
7.6
10.0
Range
23.4-28.8
0.1-0.5
0.05-0.1
0.5-0.96
10.4-19.6
0.09-0.17
69.1-85.5
16-30.9
6.4-18.6
9.4-25.1
Avg
24.9
0.2
0.07
0.71
14.7
o-.ii
77.6
.22.4
12.8
18.2
All values calculated on the basis of od total solids taken as 100- percent.
-------
TABLE 5
ANALYTICAL DATA OH FREEZE-DRIED COLOR BODIES FROM LIME-TREATED WASTE WATER
Sample Designation
Sodium, percent
Calcium, percent
Nitrogen, percent
Chloride, percent
Organic Carbon, percent
Total Solida, g/100 ml.
Fixed Solids (Ash), percent
Volatile, percent
Carbonate, percent
In Total Solids
In Fixed Solids
ET2-1C
28.5
0.1
o.o4
«*
5.5
0.11
90.6
9.4
18.6
LT3-1C
26.6
0.2
0.04
6.00
0.08
52.2
47.8
6.4
9.4
LT4-1C
27.2
-------
TABLE 6
ANALmCAL DATA ON FREEZE-DRIED COLOR BODIES FROM RETURNED WASTE WATER
Sample Designation R2-1C R^-IC R5-1C S7-1C R8-1C Range Avg
Sodium, percent
Calcium, percent
Nitrogen, percent
Chloride, percent
Organic Carbon, percent
Total Solids, g/100 ml
Fixed Solids (Ash), percent
Volatile, percent
Carbonate, percent
In Total Solids
In Fixed Solids
29.U
0.3
0.08
12.0
0.13
80.5
19-5
26.0
27.5
<0.1
0.06
0.6
10.3
0.1
83.5
16.5
20.6
27. k
<0.1
0.08
0.9
13.7
0.13
81.1
18.9
18.0
25.7
27.3
0.1
0.5
13.1
0.168
79.8
20.2
20.2
26.5
29.2
<0.1
0.52
11.5
0.17
82.5
17.5
19.7
27.3-29.**
<0.1-0.3
0.06-0.08
0.5-0.9
10.3-13.7
0.1-0.168
79.8-83.5
16.5-20.2
18.0-26.0
28.2
0.1
0.07
0.63
12.1
0.12
81.5
18.5
20.9
25.3
-------
^ 4
o»
M
O
m
U
O
1
(T
O
LI me-Treated
Untreated
20 40 60 80
COLOR UNITS AT pH 7.6
100
Figure k
10
- 8
x
(M
Correlation of Total Organic Carbon with Color Units (at
pH 1.6) of Freeze-Dried Untreated, lime-Treated, and
Returned Wastes
00
flC
o
Lime-Treated
0 20 40 60 80 100
COLOR UNITS AT pH 7.6
Figure 5. Correlation of Absorbance (at 251* nm) with Color Itaits (at
pH 1.6) of Freeze-Dried Untreated, Lime-Treated, and
Returned Wastes
19
-------
10
o
- 8
x
5
(M
H-
ui
GO
o:
o
in
s2
Returned
Untreated
Lime-Treated
I
ORGANIC CARBON x 10
Figure 6. Correlation of Total Organic .Carbon with Absorbance
(at 25U nm) of Freeze-Dried Untreated, Lime-Treated,
and Returned Wastes
20
-------
SECTION V
ISOLATION AND FRACTIONATION OF COLOR BODIES
The freeze-dried color "bodies contained a large amount of ash. They
seem to occur naturally as sodium salts. For characterization of color
bodies , it was desirable to isolate them as free color bodies and to
separate them from the inorganic constituents. Ion exchange resins,
dialysis, sorption on carbon and on synthetic resin, gel permeation
chromatography, and paper chromatography were tested as means for accom-
plishing the desired goal.
Ion Exchange Resin
Ion exchange resins are often used for removal of mineral constituents
from water. When the original wastes or waste fractions from a Bio-Gel
column were passed through a column of Amberlite IR-120 (hydrogen form),
most of the cations were removed from solution and most of the color
bodies remained in solution. Sometimes, insoluble materials separated
from the aqueous solution. This could be prevented by addition of up to
one volume of 95 percent ethanol per volume of aqueous solution. Sulfates
and chlorides in the wastes were converted to sulfuric and hydrochloric
acids by the resin and remained with the color bodies in the eluates of a
cation exchange column. Although Amberlite IR-120 seemed to be satisfac-
tory for removal of cations, a subsequent treatment to remove mineral acids
was needed.
Mixed bed resins were used to remove both cations and anions in a single
treatment. When solutions of the original wastes were passed through a
column of the mixed bed resin, Amberlite MB3, 15 to 20. percent of the color
was retained by the column and could not be recovered. In addition, the
solids passing through the column still contained 3-5 percent ash. This
was mainly silica, but its presence in the isolated color bodies was un-
desirable.
Amberlite MB3 is a mixture of strong exchange resins, Amberlite IR-120
and IRA-UlO, and thus it is possible that some of the color bodies were
sorbed on the strong anion exchange resin. However, when the waste was
treated with Amberlite IR-120 and then with the weak anion exchange
resin, namely IR-^5, 15 to 20 percent of the color was still retained by
the anion exchange resin. But in this case, at least a- part of the
sorbed color could be removed by elution with ammonium hydroxide giving
a solution containing ammonium salts with excess of ammonium hydroxide.
Presumably, the ammonia could have been removed by evaporation followed
by treatment with Amberlite IR-120 to remove ammonium ions but this was
-not done. A remaining difficulty in any case would still be the presence
of silica in the demineralized solutions.
21
-------
Dialysis
Dialysis was tested as a means of isolating the color bodies. Cellulose
acetate tubing having an average pore size of Uo A. was used for dialy-
sis at pH 10-5, 7.2, and 2.9. About 50 percent of the color passed
through the tube with the mineral constituents.
When a solution of the untreated waste was first treated with Amberlite
IR-120 to remove cations, and then was dialyzed against distilled water
using a similar tube, about 80 percent of the original color remained
in the dialysis bag and presumably was free of at least the main part of
the inorganic constituents. Since we were searching for a procedure
which would recover all of the color bodies, work on dialysis was dis-
continued.
Sorption on Carbon
Carbon is often suggested for removal of color from waste waters espe-
cially the small amounts of color remaining after other treatments.
Attempts to use Darco Grade 60 (Atlas Chemical Industries, Wilmington,
Delaware) for isolation of color bodies from the original wastes were
not successful.
When untreated waste was treated with this carbon and filtered, the
aqueous filtrate and washings had very light tan color and contained 8^
percent of the starting material by weight. The carbon containing color
bodies was washed first with 50 percent aqueous ethanol and then with 50
percent pyridine- The aqueous ethanol eluate contained 8.7 percent and
the aqueous pyridine eluate 5-6 percent of the starting material. The
color fractions, however, were contaminated with a small undetermined
amount of colloidal carbon which could not be removed by filtration. In
addition, some color was irreversibly sorbed on the carbon.
Sorption on Synthetic Resin
Information supplied by the Rohm & Haas Company representatives indicated
that the Amberlite XAD-2 resin is capable of removing color from waste
waters. When an aqueous solution of the original waste was passed
through an XAD-2 column, no appreciable color was removed. But when the
solution was first decationized by IR-120 resin and then passed through
a bed of Amberlite XAD-2 resin about one-third of the color was retained
and could be removed from the column by elution with 50 percent ethanol.
22
-------
Gel-Permeation Chromatography (GPC)
GPC was attempted as a means for obtaining ash-free color bodies from
both untreated and lime-treated decker wastes. Bio-Gel P-2 column hav-
ing an exclusion limit of molecular weight 2600, a total bed volume of
k26 ml and an approximate void volume of 162 ml was used for this pur-
pose.
Fifteen ml of 10 percent solutions of color bodies from the untreated
and lime-treated wastes were separately fractionated in the above column
at flow rates of 0.2 to 0.3 ml/min. Distilled water was used as eluent.
The eluate was monitored by a UV source at 280 nm because this is the
standard area of absorption for lignin, and the fractions were collected
at ten-minute intervals. Seventy-seven to ninety fractions were col-
lected in this way and analyzed for color, total solids, fixed solids,
volatiles (by difference) , absorbance at 280 nm, and pH. Because the
absorbance values followed the same trend as that of color, these are
not plotted here.
The data obtained for each fraction were calculated as. a percentage of
the respective parent sample (untreated or lime treated) and then divid-
ed by the volume of that fraction to obtain the percentage of color per
milliliter in each fraction. The total solids, fixed solids, and vola-
tiles were all expressed as percentages of the total solids of the
parent sample. Figures 7 and 8 are plots of these parameters and of pH
against elution volume.
A general comparison of these figures shows that:
a. Curves of untreated and lime-treated wastes display two
major peaks.
b. The total- and fixed-solids of untreated and lime-treated
wastes elute at approximately the same elution volume.
c. One of the peaks of the volatile curve of the lime-treated
waste at higher elution volume does not coincide with that
of the color curve as is the case with untreated wastes.
Figure 9 shows plots of color-to-volatile ratio of untreated and lime-
treated waste fractions versus their respective elution volumes. A
general decrease in these ratios is observed as the elution volume in-
creases. The ratios of the lime-treated fractions, as expected, are
lower than those of the untreated fractions, indicating that most of the
highly colored carbon is removed during lime treatment.
In order to further evaluate the degree of removal, ratios of the maximum
values of color, volatile- and fixed-solids at two major elution volumes
of untreated and lime-treated wastes were calculated and the results are
given in Table 7. A significant decrease in these ratios after lime
treatment indicates that comparatively higher amounts of color bodies
23
-------
x 2800
_j
or
UJ
2400
ro
o
E 2000
tn
1600
55
CD
if 1200
or
^J
QL
. 800
or
UJ
UJ
1 400
T.S. * Total Solids
F.S. s Fixed Solids
V * Volatile
(Ash)
II
PH
x
ex
8
150
200
ELUTION VOLU«E , Mi-
Figure T.
Fractionation of Untreated Dilute Kraft Mil Decker Waste.
Parameter Calculated as Percent of Untreated Waste Present
in One ml of the Collected Fraction
-------
vn
Fixed Solids
(Ash)
ZOO
250 300
ELUTION VOLUME, ML.
350
Figure 8.
Fractionation of Lime-Treated Dilute Kraft Mill Decker Waste. Parameter
Calculated as Percent of Lime-Treated Waste Present in One ml of the
Collected Fraction
-------
ro
cr\
2800
2400
p 2000
o:
LU
d 1600
ce
o
o
o
1200
800
400
I I
I t
150
200 250
ELUTION VOLUME, ml.
300
350
Figure 9. Fractionation of Untreated and lime-Treated Dilute Kraft Mill Wastes.
Ratio of Color Units to Volatiles x 103 Versus Slution Volume
-------
eluting at lover elution volumes (higher molecular weights) are removed
during lime treatment.
TABLE 7
EFFECT OF LIME TREATMENT ON WASTE FRACTIONS
Untreated lime Treated
Maximum Value at Elution Maximum Value at Elution
Volume of Volume of
167 ml 320 ml Ratio 162 ml 305 ml Ratio
(a) (b) (a)/(b) (a) (b) (a)/(b)
Color Units 2l*,000 3,600 6-7 3,000 3,000 1.0
Volatile ,
percent 2.65 1-39 2.8 67 ^9-3 1.35
Fixed Solids,
percent 0.1*6 2.l6 0.21 0.36 6.8 0.05
As the main aim of GPC, at this point, was to obtain ash-free color
bodies , the fractionated untreated and lime-treated color bodies were
combined according to the following code to give three large fractions
in each case, and analyzed for ash, volatiles , sodium, and calcium.
Approximate Elution
Combined Fractions Volume, ml
Untreated (A) Between 123 to 195
Untreated (B) Between 195 to 293
Untreated (C) Between 293 to end of
colored fraction
lime-treated (A) Between 120 to 193
lime-treated (B) Between 193 to 283
Lime-treated (C) Between 283 to end of
colored fraction
The weight average molecular weight (%) was also determined by the
ultracentrifuge and results are given in Table 8. The molecular weights
of the middle fractions (B) are the lowest in both cases. These frac-
tions also contain the highest amounts of ash which is probably respon-
sible for low My. values . It should be noted that in extremely complex
and heterogeneous mixtures, such as these, the M^ values should not be
taken as absolute values .
The data further indicate that, although fractions containing color
bodies of different molecular weights and sizes could be obtained by
GPC, it was not a very effective method for giving ash-free color bodies
under these conditions .
27
-------
TABLE 8
ANALYSIS OF FRACTIONATED COLOR BODIES
Combined
Fractions
Untreated (A)
(B)
(c)
Lime Treated (A)
(B)
(C)
Fixed
Solids
(Ash),,
percent
26.8
89.0
71-7
1*8.7
92.9
79.9
Volatile,
percent
73.2
11.0
28.3
51-3
7-1
20.1
Q
Sodium,
percent
9.1
28.3
21.5
13-3
32.9
26.2
Calcium,
percent
0.2
0.1
<0.1
0.27
<0.1
0.1
g
n,Uoo
121*
760
70
85
Analyzed in ash and calculated on respective o.d. fraction.
Paper Chromatography
Paper Chromatography "was also tried. The chromatograios produced light
tan-colored bands and zones which were separated and eluted to yield
seven fractions. Although some fractions were more highly colored than
others, all fractions carried tan to brown coloration. Furthermore, the
inorganic materials appeared to be spread over several fractions. For
this reason this method was also abandoned.
In order to further deash the color bodies, a combination method of
acidification and GPC was developed.
Acidification and Gel Permeation Chromatography
The effluent color was pH dependent. A decrease in pH decreased the
color and also precipitated some color bodies.
Although most of the color remained in solution when a dilute solution
of the waste was acidified, up to 80 percent of the color bodies could
be precipitated from a concentrated solution (13-20 percent) of the un-
treated wastes. In addition, a large portion of the color remaining in
28
-------
the acid solution could be isolated by first sorbing it on Amberlite
XAD-2 resin and then desorbing with aqueous ethanol. These techniques
were used for the isolation of acid-insoluble and acid-soluble color
bodies from the untreated and lime-treated freeze-dried solids. Ion-
recoverable color bodies have been reported as losses. The results are
given in Table 9.
TABLE 9
PERCENTAGE OF YIELD AND REMOVAL BY LIME OF
UNTREATED MD LIME-TREATED WASTE FRACTIONS
Untreated
Waste Yield. %
Fractions
Color
TOC
Lime-Treated
Waste Yield, %
Color
TOC
Removal ,
Color
TOC
Original Waste 100 100
Acid-Insoluble 63 59
Acid-Soluble 30 18
Loss (by
difference) 7 23
14.0
3.7
(26)
7-7
(55)
3.6
(8.4)
10.2
(23.8)
86.0
94.3
74.5
57.2
9k.0
43.4
2.6 29.0
(19) (67.8)
All values (except in parentheses) are calculated on the original untreat-
ed waste taken as 100.
Values in parentheses are based on original lime-treated waste taken as
100.
Q
A.P.H.A. color units.
Total organic carbon.
"^Percentage of removal was calculated on the basis of their respective
untreated fraction taken as 100.
Table 9 shows that 86 percent of total color and about 57 percent TOC
are removed by lime treatment, indicating that the remaining 43 percent
TOC contributes to only l4 percent of the original color. It is possi-
ble that part of this TOC is in the form of noncolored carbohydrate deg-
radation products, resin acids, etc. The data also indicate that the
acid-insoluble components of mill wastes lost 94.3 percent color and
94.0 percent TOC, whereas the acid-soluble components lost only 74.4
percent color and 43.4 percent TOC during lime treatment.
29
-------
Table 9 further shows that combined color recoveries of the acid-insolu-
ble and acid-soluble components were 93 percent (63 + 30) in the case of
untreated wastes and 8l percent (26 + 55) in the case of lime-treated
wastes. The corresponding TOO recoveries were 77 percent (59 + 18) and
32.2 percent (Q.h + 23-8), respectively. This indicates that 7 percent
color and 23 percent TOO in the case of untreated waste compared to 19
percent color and 68 percent TOG in the case of lime-treated waste were
nonrecoverable and remained in the acid solution. These materials were
probably of very low molecular weights.
The acid-insoluble and acid-soluble color bodies of both untreated and
lime-treated wastes were fractionated into nine to twelve fractions
using the Bio-Gel P-2 column (200 cm long and 2.5 cm in diameter) having
an exclusion limit of molecular weight 2600. The first fraction, "A,"
from each run was further fractionated into three to seven fractions
using the Bio-Gel P-60 column (100 cm long, 2.5 cm diameter) having an
exclusion limit of molecular weight 60,000. Details are given in the
experimental part of this report.
All fractions obtained from the gel columns were analyzed for color,
TOG, and absorbance at 280 nm. The data were used for calculating per-
centage yields and removal of color and TOG by lime in each fraction.
Results are given in Tables 10 and 11.
The individual values for Fractions A3 through A7 and D through M were
small compared to other fractions and so have been tabulated as combined
values for easy reference. The detailed data are given in Appendix I.
Appendix I shows that the amounts of material input and output during
fractionation fluctuated and some losses were observed in the mass
balance. The calculations of these losses were, however, based on cumu-
lative values of all fractions and so the error per fraction would cer-
tainly be a lot smaller. Maximum loss (32 percent) was observed in TOG
values when the untreated acid-insoluble fraction "A" was further frac-
tionated on Bio-Gel P-60 column. It is believed that this loss was due
to the retention of some low molecular weight material which did not
elute out at the collected elution volumes.
In the case of untreated acid-insoluble color bodies (Table 10), 79 per-
cent of the color (1*9-8 x 100/63) and 55.6 percent of the TOG (32.8 x
100/59) were obtained in Fraction A, whereas in the case of lime-treated
acid-insoluble color bodies this fraction contained only 32.k percent of
the color (1.2 x 100/3-7) and 19 percent of the TOG (0.68 x 100/3.6).
Worth noting is the fact that the general trend of effective removal of
color and TOG by lime treatment decreased below Fraction B.
In the case of untreated acid-soluble color bodies (Table 11), on the
other hand, 33 percent color (9.9 x 100/30) and 23 percent TOG (U.2 x
100/18) were obtained in Fraction A, whereas in the case of lime-treated
acid-soluble color bodies this fraction contained only 25 percent color
(1.9 x 100/7.7) and 19.5 percent TOG (2 x 100/10.2), indicating that
30
-------
most of the acid-soluble color bodies are of lower molecular weights
lables 10 and 11 also show that the percentage of removal of acid-
soluble color bodies by lime was much lower than that of the acid-
insoluble color bodies.
TABLE 10
FRACTIONATION OF ACID-INSOLUBLE COLOR BODIES BY COLUMN CHROMATOGRAPHY
(Material balance of color and TOC)
Fractions
Fraction *A' from
P-2 thru Bio-Gel P-60
column
Al
A2
A3 thru A5
Acid-insoluble color
bodies thru Bio-Gel
P-2 column
A
B
C
D thru if
Uhfractionated acid-
insoluble color bodies
Untreated
Aci d-Ins oluble
Color Bodies
Yield. %
Color
11.7
19-9
18.2
U9.8
7.6
1.9
3-7
63.0
TOC
6.8
9.7
16.3
32.8
6.5
1.1
18.6
59.0
Lime-Treated8
Aci d-Ins oluble
Color Bodies
Yield. %
Color
0.67
0.38
0.15
1.20
0.30
0.18
2.02
3.70
TOC
0.22
0.13
0.33
0.68
0.2U
0.22
2.1)6
3.60
Removal, %
Color TOC
98.0
99-1
97-5
96.0
90.5
1*6.0
96.8
98-7
98.1
98.0
96.2
80.0
86.5
».0
Percentages of yield are calculated on the basis of untreated original vaste.
bCalculated by difference so that values for A = (A1+A2+A3 thru A5).
C Calculated by difference so that values for unfractionated acid-insoluble color
bodies = (A+B+C+D thru M).
Our experience has shown that GPC runs could not be quantitatively dupli-
cated. However, they showed similar trends. In order to compare frac-
tions of different wastes with each other and to minimize the experiment-
al error, especially because there was no clear-cut demarcation line
between the two adjacent fractions, the data in Appendix I were divided
by their respective fraction volumes and the values per ml thus obtained
were plotted against eluate fractions in Figures 10 to 13-
Absorbance value at 280 nm for each fraction was also measured and when
plotted as above, gave a pattern similar to that of color and, therefore,
is not included in this report.
31
-------
TABLE 11
FRACTIOHATION OF ACID-SOLUBLE COLOR BODIES BY COLUMN CHROMATOGRAPHY
(Material balance of color and TOC)
Fractions
Fraction 'A' from P-2
thru Bio-Gel P-60 column
Al
A2
A3 thru A7b
Acid-soluble color
bodies thru Bio-Gel
P-2 column
A
B
C
D thru M°
Unfractionated acid-
soluble color bodies
Untreated
Acid-Soluble
Color Bodies
Yield. %
Color
0.8
1.2
7.9
9.9
7.5
9^2
30.0
TOC
0.6
1.0
2.6
5.0
2.8
6.0
18.0
Lime-Treated
Acid-Soluble
Color Bodies
Yield, %
Color
0.07
0.13
1.7
1.9
0.7
1.5
3.6
7-7
TOC
0.06
0.25
1.69
2.0
1.1
2.5
U.6
10.2
Removal. %
Color
91.2
89.0
78.5
80.8
90.6
56.0
61.0
TOC
90.0
75.0
35.0
52.5
78.0
10.7
Percentage yields are calculated on the basis of untreated original waste.
Calculated by difference so that values for A = (A1+A2+A3-A7)
cCalculated by difference so that values for unfractionated acid-soluble color
bodies = (A+B+C+D thru M).
The dotted areas between the untreated and lime-treated curves in Fig-
ures 10, 11, 12, and 13 correspond to the amounts of color, and TOC
removed by the lime-treatment process. A comparison of these figures
indicates that lime treatment removes more color and TOC from the acid-
insoluble color bodies than acid-soluble color bodies. These figures
also shov that the TOC patterns for different wastes are not similar to
their respective color patterns, indicating the presence of "noncolored"
organic carbon in some of these fractions.
321-
-------
P-60
P-2
8
Figure 10.
Untreated
Acid-Insoluble
Lime-Treated
Acid-Insoluble
^B|^I^^^^^^^^^^^^^^^^^^^Bf££^P
A5 C E G J L .
B D F H K M
ELUATE FRACTIONS
Fractionation of Acid-Insoluble Color Bodies. Color Units
Calculated as Percent of Untreated Waste Present in One Ml
of the Collected Fraction
P-60
A2 A4
Untreated
Acid-Insoluble
Lime-Treated
^/ Acid-Insoluble
"I "3 A5
A2 A4 B D F H K
ELUATE FRACTIONS
Figure 11. Fractionation of Acid-Insoluble Color Bodies. TOC Calcu-
lated as Percent of Untreated Waste Present in One Ml of
the Collected Fraction
33
-------
250r
-, 200
I
at
IK
3
8
150-
100-
50
P-60
Untreated
Acid-soluble
Lima -Treated
_. Acid-soluble
i *. i
A, A, A5 A7 C E 6 J L
A2 A4 A6 B D F H K M
ELUATE FRACTIONS
Figure 12. Fractionation of Acid-Soluble Color Bodies. Color Units
Calculated as Percent of Untreated Waste Present in One
Ml of the Collected Fraction
250
200
- 150-
. 100-
50-
P-60
P-2
A, As AT C
Untreated
Acid-soluble
Lime-Treated
Acid-voluble
E 6 J L
A2 A4 A6 B D F H K M
ELUATE FRACTIONS
Figure 13. Fractionation of Acid-Soluble Color Bodies. TOC Calcu-
lated as Percent of Untreated Waste Present in One Ml
of the Collected Fraction
-------
SECTION VI
CHARACTERIZATION OF COLOR BODIES
Elemental Analysis
Acid-insoluble and acid-soluble fractions were isolated from three un-
treated and two lime-treated wastes . Color of each fraction was deter-
mined by the American Public Health Association method9, and the recovery
was calculated on the basis of the original color. Five fractions were
analyzed for carbon, hydrogen, methoxyl, nitrogen, and ash. Absorp-
tivities (absorbance/solids in g/l) were determined at k2Q nm (ai^o) as
a measure of original color, and at 280 nm (aaso) and the maximum near
200 nm (a^^.) as a measure of the lignin content. The results are sum-
marized in Table 12. Absorptivities for Indulin 'C' and analytical data
for an alkali lignin from pinewood are included in the table. Analytical
data were not obtained for Indulin C, but the values for the alkali lig-
nin are believed to be good approximations of the composition of Indulin.
The data in Table 12 include three values which may be used as approxi-
mate measures of lignin content, namely: methoxyl, absorptivity at 280
nm and absorptivity at the maxim-um. Calculated ratios of absorptivity
at lj-20 nm (as a measure of color) to each of these are included in the
table.
The data suggest that at least most of the color bodies are ligninlike
and that they consist of lignins which have been degraded to varying
degrees. The lignin in all of the wastes appear to have lost somewhat
more methoojyl than Indulin C, with those in the more soluble fractions
having lost the greatest amount of methoxyl. The loss in methoxyl of
the more soluble fractions was not checked by determining the corre-
sponding increase, if any, in the phenolic group content.
The ratios of the absorptivity at 1*20 nm to the methoxyl content, the
absorptivity at 280 nm and at the 'maximum' suggest that, except for
some greater loss of methoxyl, the lignins in the acid-insoluble frac-
tions from the untreated wastes are very similar to the lignins in
Indulin C. The lignins in the untreated acid-soluble fractions and
those from the lime-treated acid-insoluble and acid-soluble fractions
appear to have been more degraded. Goring, et_ a_L. °* have indicated
that, during pulping, the very low molecular weight lignins are not
produced by degradation of the high molecular weight lignins. The
authors further indicate that one of the two types of protolignins
present in softwoods gives very low molecular weight lignins whereas
the other gives high molecular weight lignins.
Our use of the word "degraded" is based on the observation that color
decreases during the handling and storage of liquid wastes. Such changes
35
-------
TABLE 12
COMPARISON OF ACID-INSOLUBLE AND ACID-SOLUBLE FRACTIONS WITH INDULIN
(Color Recovery, Analytical Data, and Absorptivity)
U4-1C
Original Waste
V
Fraction Ind-ulin"
Color Recovery,
percent
Carbon, percent
Hydrogen, percent
Nitrogen, percent
Ash, percent
"Oxygen" by
Difference, percent
Methoxyl (MeO),
a percent
a420
a
a280
a
amax
A
A /Maft Pla+^ rt
kwv «»uio
a4ao/a28o Ratio*
WVx*11*10*
63.4
5.6
--
31.0
14.2
1.54
19.0
83.2
o.u
0.081
0.018
Acid-
Ins.
84
55-34
5.25
0.36
9.78
29.3
11.23
1.38
16.7
77.5
0.12
0.083
0.018
Acid-
Sol.
14
~
__
0.74
10.5
51.6
0.070
o.oi4
U7-1C
Acid-
ins.
63
56.89
5.30
0.33
7.81
29.7
8.51
1.41
16.9
78.0
0.17
0.083
0.018
Acid-
Sol.
30
*7.92
4.87
0.68
6.04
40.5
5.20
1.25
12.9
51.9
0.24
0.097
0.024
U8-1C LT7-1C
Acid- Acid- Acid-
Ins. Sol. Ins.
46 42 26
51.82
5.55
0.25
17.18
25.2
4.09
1.09 0.95 0.72
13.2 14.1 10.5
73.1 60.6 56.8
0.18
0.083 0.067 0.069
0.015 0.016 0.013
Acid-.
Sol.
55
48.30
5.47
0.42
4.56
41.2
4.37
1.04
12.1
50.0
0.24
0.086
0.021
LT8-1C
Acid-
Ins.
36
_
0.64
10.5
68.4
0.061
0.009
Acid-
Sol.
54
0.92
12.1
63.4
0.076
o.oi4
ali20> a28o' a ' are ^sorP'ti^'ti63 a^ i*20 nm> ^80 nm, and maximum, respectively.
Analytical data for an alkali lignin from pinewood, absorptivities for Indulin C.
-------
are possibly due to the degradation of color bodies - which are believed
to be of lignin origin.
Analysis of Fractions Obtained by Gel Permeation Chromatography (GPC)
Fractions of acid-insoluble and acid-soluble color bodies from the un-
treated and lime-treated vastes were obtained by GPC, but several of
these fractions were very small, especially after keeping aside the
amounts required for the estimation of molecular weights.
To provide sufficient material for chemical analysis some adjacent frac-
tions which were similar with regard to their ratios of color to organic
carbon were combined to give bulky fractions. Only the acid-insoluble
color bodies from the untreated waste, were found to be enough for
chemical analysis. Molecular weight (M^), color yield, color/carbon
ratio, carbon, hydrogen, methoxyl and ash data of these bulky fractions
are given in Table 13, along with data for acid-insoluble color bodies
and an alkali lignin taken from Table 12 (some of the original inter-
mediate fractions were not analyzed).
The variable ash content in Table 13 makes direct comparisons difficult.
Since the composition of the ash is unknown, corrections to ash-free
basis seems questionable. Instead, ratios of methoxyl to carbon are
calculated. The results indicate that gel permeation chromatography
resulted in fractionation of chemical classes as well as molecular
sizes. The lowest molecular weight fraction had a very- low ratio'Of
methojxyl to carbon (O.OU) indicating little ligninlike material. All
of the fractions probably are mixtures and, thus, a low methoxyl con-
tent may be due to a high proportion of nonlignin materials, as well
as to the presence of highly degraded lignins. Infrared spectroscopy
Csee below) has also shown that very soluble colored fractions (low
molecular weight) are associated with the carbohydrate material.
Sugar Analyses of Untreated and Lime'-Treated Wastes
Sugar analyses of acid-insoluble and acid-soluble color bodies from the
untreated and lime-treated wastes and their fractions obtained by gel
permeation chromatography were conducted by the method of Borchardt and
Piper12. The following sugars: rhamnose, arabinose, xylose, mannose,
galactose, and glucose, were found and are reported as anhydrous sugars.
As the amounts of individual sugars in each fraction were small, only
the total sugar values of the major fractions are reported in Table lU.
(For detailed data see Appendix II.) Indulin value is included for
comparison only.
Table 1^ shows that the total amount of sugars present in Indulin is
1.0? percent, in untreated waste 1.51 percent, and in lime-treated
waste 2.92 percent (Column I). About 17 percent (100-82.8) sugars of
the untreated waste is removed during the lime treatment process, thus
contributing to some BOD removal. Column III of the table shows that
in the case of the untreated waste 62-5 percent of the sugars are
37
-------
oo
TABLE 13
ANALYTICAL DATA ON FRACTIONATED ACID-INSOLUBLE COLOB BODIES FROM UNTREATED WASTE
Fractions
Fraction 'A' from P-2
Wt Ava
Mol Wt
-------
obtained in the acid-insoluble fraction and 32 percent in the acid-solu-
ble fraction. On the other hand, in the case of the lime-treated waste,
these percentages are reduced to 6 percent and 19 percent, respectively.
A total of about 58 percent of the sugars are not recovered in the acid-
insoluble and/or acid-soluble fractions of the lime-treated waste. It
is believed that these sugars, probably in polymeric form, are originally
attached to the color bodies and during the lime treatment process (pH
12-13) are released in the polymeric form without further degradation
(according to Mr. Dickey of the Institute, reducing sugars will be de-
stroyed by lime but polymeric sugars ordinarily will not be touched).
These sugars ultimately end up with the nonrecoverable low molecular
weight material reported as TOG losses after the acid treatment (see
Table 9 and Appendix I),
TABLE 1H
SUGAR ANALYSES OF UNTREATED AID LIME-TREATED WASTES
Total Sugars, %
Fractions
In dull n
Untreated Waste
Acid-insoluble color bodies
Acid-soluble color bodies
Nonrecoverable (loss)
Lime-Treated Waste
Acid-insoluble color bodies
Acid-soluble color bodies
Nonrecoverable (loss)
I
1.07
1-51
1.60
2.69
2.92
2.39
2.86
__
II
1-51
0.9^5
o.hQh
0.08.
1.25
0.09
0.29
0.87
III
100
62.5
32.1
5.J»
82.8(100)
6.0(7-2)
19.2(23.2)
57.6(69.6)
Column I = sugar values are based on moisture free solids in "individual
fractions."
Column II = sugar values are based on moisture free "total solids in
untreated waste."
Column III = sugar values are based on "untreated waste sugar" content
taken as 100.
The values in parentheses are based on the lime-treated waste taken as
100.
39
-------
Ultraviolet and Visible Spectra
Ultraviolet and visible spectra of Indulin 'A1 and acid- insoluble and
acid-soluble fractions isolated from the untreated and two lime-treated
vastes were determined at a pH of about "J.6.
Absorptivity values from these spectra were calculated at definite wave-
lengths and the results of untreated and lime-treated series are plotted
in Figures lk and 15".
3.0i-
2.5
e 2.0
o
1.5
o.
a:
o
3 i.<
0.5
300
Indulin
-Acid-insoluble]
Acid-soluble J
Untreated
-Acid-insoluble"!. . 4 .
* -., , > Lime-treated
.Acid-soluble J
400 500
WAVE LENGTH, nm
600
Figure lU. Absorptivity Versus Wavelength (Visible Range) of Indulin
"A," Acid-Insoluble and Acid-Soluble Color Bodies of Un-
treated and Lime-Treated Kraft Mill Decker Wastes
-------
Acid-insoluble]
Acid-soluble J
Untreated
Lime-treated
200
250
300
350
WAVE LENGTH, nm
Figure 15. Absorptivity Versus Wavelength (Ultraviolet Range) of
Indulin "A," Acid-Insoluble and Acid-Soluble Color
Bodies of Untreated and Lime-Treated Kraft Mill Decker
Wastes
Ul
-------
Figure 1^ shows that in the -visible range all samples gave simple absorp-
tion curves and exhibited an increase in absorptivity as the wavelength
decreased. Comparatively, the lime-treated color bodies showed lower
absorptivity values than the untreated color bodies . However, the lime-
treated acid-insoluble color bodies showed the lowest absorptivity
values, even lower than acid-soluble color bodies. This is not surpris-
ing as the lime-treated acid-insoluble color bodies contained only 3.7
percent of the original color and lime-treated acid-soluble color bodies
contained 7-7 percent of the original color (see Table 9)-
In the ultraviolet range (Figure 15) one reaches the same conclusions as
in the visible range except that here the characteristic absorption bands
at 205 nm and 280 nm are obtained.
It can be said that all fractions contain ligninlike color bodies. The
differences in absorptivity values, can be due to differences in ash
contents and different levels of degradation of color bodies.
Infrared Spectra
Infrared (IR) spectra were determined for acid-insoluble and acid-solu-
ble components of both untreated and lime-treated wastes (Figure 16).
The IR spectra were analyzed to see whether or not important functional
group differences were associated with the differences in the treatment
prior to isolation. It should be realized that detailed interpretation
of many of the absorption bands is not possible because of the complex-
ity of the molecular system, uncertainties always present in comparison
of solid state spectra, and the interference by impurities (elemental
analyses revealed ash contents from U.5& to 17-18 percent).
In the following discussion, frequent reference will be made to compari-
sons of sample spectra with a spectrum of Indulin A.
Acid-Soluble Samples (Untreated arid Lime-Treated)
The spectra of untreated and lime-treated samples were nearly identical;
the differences that do exist are solely minor differences in the rela-
tive intensities of a few bands, and it would be unwise to assign a
specific structural difference as the cause of these intensity changes.
It is possible, however, to comment on the absorption in certain spec-
tral regions and the implications to the structural question for the
acid-soluble samples.
1. OH and CH stretch (2500-3600 cm'1)
It is impossible to make meaningful comparisons of the
OH intensities from one sample to another because of the
variable amounts of water in the samples. However, there
is one consistent difference between the Indulin A sample
-------
00
4000
3000
800
4OO
2000 1600 1200
W&VENUMBER (CM'1)
Figure 16. Infrared Spectra of Kraft Mill Decker Effluent Color Bodies
-------
and all of the acid-soluble samples, and that is the greater
breadth of absorption in the acid-soluble sample spectra
in the 2500-3600 cm"1 region. These spectra all contain
pronounced shoulders at about 2650 cm vhich are charac-
teristic of carboxylic acid dimers. Hence, it appears that
earboxylic acid groups are more prevalent in the acid-soluble
materials than in Indulin A.
2. C=0 stretch "(1680-1730 cm"1)
Indulin A shows a carbonyl absorption centered at about
1690, but it is quite broad (water contribution?) and is
of medium intensity. All of the acid-soluble sample spectra
show strong carbonyl absorption at approximately 1715 cm
This may primarily reflect the greater abundance of carboxyl
groups already suggested, but it would also be consistent
with other types of carbonyl systems.
3. Aromatic ring vibrations (1^501600 cm *)
The three most important bands due to skeletal vibrations
of the aromatic ring are those at about 1^60, 1500, and
1600 cm a. The spectrum of Indulin A shows these bands
at 1^60 medium-strong intensity, 1510 strong, and 1595
medium. The spectra of the acid-soluble materials contain
all of these bands although the relative intensities are
somewhat different and they vary from sample to sample (the
1595 band, is affected somewhat by the water absorption band
which it partly overlaps).
k. The region 1000-0.^00 cm"1
In this fingerprint region, the Indulin A spectrum shows
five distinct absorption bands. The acid-soluble materials
contain one of these at 1030 cm : (probably due to ether
linkages), but the remainder of the region contains a very
broad absorption band with several inflections. The broad
character of this absorption can, in part, be due to the
inorganic material present; sulfate salts give strong
absorption in the region 1080-1130 cm l.
The intensity of the bands in this area is greater relative
to the aromatic vibrations (l^60-l60Q. cm"1) that exist
for the Indulin A spectrum. It is unlikely that sulfate
absorption is the sole cause. Such a difference in inten-
sities might be due partly to carbohydrate material present
in the acid-soluble samples. However, such an inference
demands additional support.
The spectrum of Indulin A contains an absorption minimum
at ikOO cm -1, but the acid-soluble sample spectra show
-------
a broad absorption plateau at this frequency. This dif-
ference was also noted between the acid-soluble and acid-
insoluble samples. The reason is not clear; carboxylic
acid groups should contribute absorption to this region
and may be partly responsible.
5- Out-of-plane C-H bonding (750-900 cm'1)
The spectrum of Indulin A contains weak absorption bands
at 812 and 850 cm"1. This is comparable to what would
be expected for a guaiacyl system (l52,U-trisubstituted
aromatic).
Although they are weak bands, these absorption bands are
still quite evident in the spectra of the acid-soluble
samples. Hence, it would appear that orientation of groups
on the aromatic rings is not markedly different from Indulin
A.
Acid-Insoluble Samples (Untreated and Lime-Treated)
The spectra of untreated and lime-treated samples were similar but not
identical. The differences were more substantial than was the case for
the acid-soluble samples. These differences will be mentioned below in
the appropriate sections.
1. OH and CH stretch (2500-3600. cm"1)
The very broad absorption in this region previously mentioned
for the acid-soluble samples was also found for the acid-
insoluble samples. Here again the broad absorption contained
a pronounced inflection at 2650 cm"1. It thus appears that
carboxylic acid groups are present in both the acid-soluble
and acid-insoluble samples, and they are more prevalent in
these samples than in Indulin A.
The lime-treated and untreated samples (acid-insoluble)
gave virtually the same spectra in this limited region.
An interesting difference between the acid-soluble and
acid-insoluble samples is revealed by the CH component of
this absorption. The acid-insoluble materials show a much
better resolved aliphatic CH absorption band at 29^0 cm l.
It is also a more important component (intensity) of this
broad absorption envelope than is the case for the acid-
soluble material.
2. C=0 stretch (l680-1700 cm"1)
The carbonyl band in these spectra was a strong absorption
band at about 1695 cm"1. Its position is essentially the
1*5
-------
same in lime-treated and untreated samples. The absorption
is_considerably stronger and sharper than the band at 1690
cm * found in the spectrum of Indulin A.
The difference of approximately 20 cm" l between the carbonyl
bands of the acid-soluble and acid-insoluble samples is
significant and appears to suggest some important differ-
ences in carbonyl groups. The 1695 band in the acid-insolu-
ble samples could be a result of an appreciable quantity of
conjugated carbonyl units. These carbonyls could be present
as ketones, acids or both. A reasonable conclusion is that
the acid-insoluble samples contain a greater, amount of con-
jugated carbonyl groups than the acid-soluble samples.
3. Aromatic ring vibrations (1^50-1600 cm"1)
The three characteristic bands for aromatic (including
lignin) structures are again evident. The relative in-
tensities of these bands differ somewhat from sample to
sample. The ratio of absorbances for the bands at 1510
and 2900. were examined since the former is a relatively
"pure" aromatic band and the latter is due to aliphatic
methylene and methyl groups. The comparison revealed that
the ratio AISiQ/A-zaoo is lower in the acid-insoluble
materials than in Indulin A. This result coupled with
the preceding discussion of the CH absorption band at
2900 seems to suggest that, in comparison to Indulin A,
the acidsoluble and acid-insoluble samples contain dif-
ferent proportions of aliphatic and aromatic structural
groups.
k. The region 1000-1^20 cpT1
The broad absorption band (1100-1300 cm~a) which is
present in the acid-soluble samples is not duplicated
in the acid-insoluble samples. The untreated samples
gave spectra containing five peaks and resembling the
Indulin A spectrum. Two of these peaks are not evident
in the spectra of the lime-treated samples, but the higher
percentage of inorganic material (11-17 percent ash) in
these samples probably contributes to the strong absorption
at 11^0 cm -1 and could well mask other bands in that
neighborhood.
Indulin A gave a peak at lij-25 cm 1 which also appeared
in the untreated acid-insoluble sample spectra. However,
the lime-treated acid-insoluble samples showed only a
shoulder at that frequency. The 1^25 cm l band in lignin-
containing-materials is generally assigned to C-H bonding
in methoxyl groups; therefore, the intensity differences
are probably due to a relatively low methoxyl content in
-------
the lime-treated acid-insoluble samples. The experimental
methoxyl contents in the samples correlate well with the
relative intensity of the lU25 band in the sample spectra.
Hie minimum at IHOO cm~ l which is present in the Indulin
A spectrum is also present in the acid-insoluble samples
which contrasts with the acid-soluble samples. The acid-
insoluble sample spectra contain an additional band at
1385 cm which is not present in the Indulin A spectrum.
In this respect, there seems to be little difference be-
tween the acid-soluble and acid-insoluble samples. The
significance of the 1385 cm"1 band is not clear.
5. Out-of-plane C-H bonding (750-900 cm""1)
There is an interesting difference (relative to Indulin A)
in this area with regard to the relative intensities of
the 820 and 855 cm x bands. In Indulin A these bands
are comparable in intensity, as is the case with the un-
treated sample, whereas the lime-treated acid-insoluble
samples show a much more intense band at 820 than the
ill-defined band at 855 cm"1. This region characterizes
the substitution pattern of. aromatic rings so the differ-
ence observed might indicate a change in the substitution
pattern (possibly due to condensation). However, the value
of these bands as good group frequencies is markedly reduced
if an electron-withdrawing group (such as a carbonyl group)
is attached to the aromatic ring. Thus, the difference
observed may be related to the observation discussed earlier
concerning the presence of conjugated carbonyl groups.
Perhaps these carbonyl groups are conjugated directly with
the aromatic ring, and the relative intensities of the bands
at 820 and 855 cm"1 are perturbed as a result of this con-
jugation.
The observations from the IR study are summarized as follows:
The acid-insoluble and acid-soluble components of both untreated and
lime-treated samples, as well as Indulin A, gave absorption bands at
1^60, 1500, and 1600 cm"1, indicating the presence of aromatic struc-
tures .
Both acid-soluble and acid-insoluble samples show greater carboxylic
acid absorption than does Indulin A. Indulin A gave a relatively weak
carbonyl band at l690 cm" V whereas the acid-insoluble fractions gave a
strong band at about 1695 cm"1 and the acid-soluble fractions gave a
strong band at approximately 1715 cm"1. Different carbonyl stretching
frequencies distinguish the acid-soluble from the acid-insoluble samples
but lime treatment itself does not influence these frequencies. The
acid-insoluble fractions seem to contain a high proportion of carbonyl
-------
groups (carboxyl, ketone, or both) conjugated with an aromatic ring,
vhereas the acid-soluble fractions seem to contain nonconjugated carboxyl
groups.
The intensities of bands (ll)-25, 1^50 cm l) normally associated vith
methoxyl groups correlate well with the experimental methoxyl contents.
Comparison of bands (1500-1600, 2900-3100 cm"1) related to aromatic and
aliphatic structures suggest possibly marked differences between the
acid-soluble and acid-insoluble materials.
The acid-insoluble samples show greater differences as a result of lime
treatment, but these differences may be entirely due to differences in
ash and methoxyl content. The acid-soluble samples reveal very few, if
any, significant differences as a result of lime treatment.
The broad, intense absorption band near 1200 cm 1 in the spectra of acid-
soluble materials may be due, in part, to associated carbohydrate mate-
rial.
Molecular Weight Distribution
Molecular weights of some selected fractions of acid-insoluble and acid-
soluble components of the untreated and lime-treated color bodies were
determined by the sedimentation equilibrium method using the analytical
ultracentrifuge^3. The maximum and minimum values, in other words the
molecular weight ranges, of the abovementioned color bodies, are plotted
in Figures 17, 18, 19, and 20., The dotted area represents the molecular
weight ranges and also indicates the heterogeneity of each fraction. To
simplify matters, the apparent "weight average" molecular weights (.M^)
for each fraction were calculated from the range data and are plotted in
Figures 21 and 22.
Figure 21 shows that M^ of untreated acid-insoluble coinponents are much
higher than that of the lime-treated acid-insoluble component. The M^
values drop sharply, level off, and then rise slightly near fractions
"j" and "K." Theoretically, the gel chromatography should yield samples
with regularly decreasing molecular weights. The reason for this shift
in property of the gel was not pursued.
Acid-soluble color bodies, on the other hand, seem to behave differently
(Figure 22). In this case, the Al and A5 fractions of the lime-treated
color bodies show higher M^ values than that of the untreated color
bodies. It seems that some of the higher molecular weight material in
the lime-treated color bodies did not precipitate out during the acid
treatment, indicating a slightly different character. It should be
noted here also that comparatively more color remained in solution when
the lime-treated material was acidified (see also Table 9).
1*8
-------
P-60
P-2
64r
KA?~\-'i-.'i.-'S..--'A.
LNQ'S
A2A4BDFHKMPRT
ELUATE FRACTIONS
Figure 1?. Molecular Weight Ranges and Distribution of
Fractionated, Itotreated Acid-Insoluble Color Bodies
-------
P-60
P-2
UJ
fc
I
a
UJ
-------
28r
A2 A4 A6 B D F
ELUATE FRACTIONS
H
Figure 19-
Molecular Weight Ranges and Distribution of
Fractionated, Untreated Acid-Soluble Color
Bodies
51
-------
28r
A2 A4 A6 B D F M
ELUATE FRACTIONS
M
Figure 20. Molecular Weight Ranges and Distribution of
Fractionated, Lime-Treated Acid-Soluble
Color Bodies
52
-------
IO
O
32
28
24
20
16
12
8
P-60
P-2
I I III
A, A3 A5 C E 6 J L N Q S
A2A4BDFHKMPRT
ELUATE FRACTJONS
Figure 21. Weight Average Molecular Weight (M^) Distribution
of Fractionated Acid-Insoluble Color Bodies
-------
20r
16
to 12
o
8
P-60
Lime Treated
Untreated
P-2
i t
A3 A5 A7 C EG J L
D F H K M
ELUATE FRACTIONS
A2 A4 A6 B
Figure 22. Weight Average Molecular Weight (M^) Distribution
of Fractionated Acid-Soluble Color Bodies
The percentage removal of color was calculated from the analytical data
for both acid-insoluble and acid-soluble components and is plotted
against their respective molecular "weight averages" in Figures 23 and
2k.
Figure 23 shows that color bodies, in the acid- insoluble components,
having a M^ of less than kOO are not removed by the lime treatment and
those above M^ 5000 are completely removed. The intermediate range
hOO to 5000) apparently undergoes partial removal. However, over 80
percent removal occurs above a 1% of 700 and 1000.
In the case of the acid-soluble component, percent removal levels off at
85 (Figure 2k).
This suggests that any treatment which will increase the molecular size
and weight of color bodies will favor complete removal.
-------
80-
60-
40
20-
- I
Partial
Removal
Zone
Complete
Removal
Zone
1000
9000
50007000
Mw, ACID-INSOLUBLE COLOR BODIES
Figure 23. Weight Average Molecular Weight (M^) of Acid-Insoluble Color
Bodies Versus the Degree of Removal "by lime Treatment
100
80
^ 60
*
I
5 40
ce
20
Partial Removal Zone
1000 3000 5000
Mw, ACID-SOLUBLE COLOR BODIES
Figure 2k. Weight Average Molecular Weight (M^) of Acid-Soluble Color
Bodies Versus the Degree of Removal by lime Treatment
55
-------
Electrokinetic Properties
Gel electrophoresis llf was used to achieve migration of color bodies
under an electric field. All color bodies migrated toward the anode,
indicating that they were negatively charged.
Electrophoretic mobilities were calculated according to Ornstein 5 and
relative mobilities were obtained by dividing these values by the
Indulin C values. Results are given in Table 15
Except for one untreated acid-insoluble fraction, and two lime-treated
acid-soluble fractions, all color bodies showed higher mobilities than
Indulin, indicating a higher density of negative charge per molecule.
This suggests that the color bodies are more degraded than Indulin.
Pyrolysis Gas Chromatography of Color Bodies
In order to learn as much as possible from the small amounts of color
bodies available, pyrolysis gas chromatography was carried out. A com-
parison of the complex chromatograms of selected color bodies to those
obtained from a kraft liquor (Indulin C) qualitatively supported the
other data which relate these fractions to kraft lignin. It might be
expected that the more highly degraded smaller molecules found in the
acid-soluble fractions would at least resemble lignin in chemical be-
havior. An inspection of Figure 25 indicates that the chromatograms
of the several pyrolyzed fractions appear to be consistent with these
hypotheses:
(l) the color bodies are degraded lignin fragments,
(2) the lower the solubility in acid and the higher the
molecular weight the more nearly do the fractions resemble
isolated kraft lignin.
Although such chromatograms are relatively complex, it may be possible
to utilize the technique in future studies to elucidate further the
chemical nature of such materials.
56
-------
TABLE 15
RELATIVE MOBILITIES OF COLOR BODIES BY
GEL ELECTROPHORESIS
Sample
Untreated acid-insoluble fractions
Al-2
AV-5
B-C
D-K
L
M-T
Untreated acid-soluble fractions
Al-3
A^
A5-6
B-J
Lime-treated acid-insoluble fractions
Al-2
A3, B-M
Lime-treated acid-soluble fractions
Ai-7
B-F
G
H
J
K
L
Relative
Mobility
0.969
1.051
1.010
1.092
1.05U
1.033
1.030
1.010
1.071
1.071
1.071
1-071
1.010
1-05U
1-033
0.989
0.989
1.033
1.076
Charge on
Color Bodies
Negative
"
"
"
"
"
"
"
"
"
"
"
Ability of color bodies divided by that of Indulin
'C.
57
-------
Lime-treated acid-soluble
'A 1-7(0.39 mg.)
Untreated acid-soluble
A 1-3(0.38 mg.)
Lime-treated acid-insoluble
A 1-2(0.40 mg.)
D-M0.35 mg.)
s~* -~~-S
B-C (0.37 mg.)
INDULIN "C (0-39 mg.)
Note! Attenuation 16 except where noted
10
40
50
Figure 25.
20 3O
TIME (MIN.)
Pyrolysis Gas Chromatograms of Fractionated Color
Bodies from the Kraft ML11 Decker Effluents
58
-------
SECTION VII
EXPERIMENTAL
Processing and Freeze-Drying of Wastes
Untreated and lime-treated colored samples were concentrated -under re-
duced pressure to one-tenth of their original volume. (Untreated
samples, if concentrated further, were very difficult to freeze-dry.)
Most of the calcium, especially in the lime-treated samples, was pre-
cipitated by carbonating the samples to a pH of 10.2. The carbonated
samples were then centrifuged in the Bet a-centrifuge at 9000 rpm for 15
minutes. This speed and time was sufficient to give clear solutions.
If, in some cases, slight turbidity was still present, these samples
were filtered through a Millipore filter paper. The pH of the solution
was checked at every stage. The colored but clear solutions were frozen
in strong glass containers (centrifuge bottles) and dried under high
vacuum. This freeze-^dried material formed a low density powder and was
readily soluble in water. The dried samples could be kept in airtight
bottles for longer periods without any significant change.
Isolation of Acid-Insoluble Color Bodies from Freeze~Dried Solids
Freeze-dried solids of the untreated waste (lU.3 g od basis) were dis-
solved under mechanical stirring in 60 ml of water and approximately 1?
g of clean cellulose powder (Whatman standard grade) was suspended in
the solution. The stirring was continued and the pH was adjusted to 1.0
with strong hydrochloric acid (.1 vol concentrated acid to 2 vol of dis-
tilled water). The acidified mixture was filtered through a precoat of
about h g of cellulose powder on a Buchner funnel and the filter cake
was washed with a total of 50 ml of water in small portions. When the
filtrate was just acid to Congo Red paper, some of the precipitate pep-
tized and formed a cloudy filtrate. The cloudy filtrate was mixed with
about 3 g of acid-washed Fibra-Flo 11C (Johns-Manville filter aid), the
mixture was filtered on a thin precoat of Fibra-Flo on a small Buchner
funnel, and the filter cake was washed with water.
Both the cellulose powder and the Fibra-Flo filter cakes were separately
extracted with 50 percent aqueous ethanol. The alcohol was evaporated
from the combined solution at reduced pressure whereupon a finely divid-
ed precipitate formed; the slurry containing this precipitate was subse-
quently freeze-dried, and designated as -"acid-insolubles." The aqueous
filtrate contained the "acid-soluble" material.
59
-------
Isolation of Acid-Soluble Color Bodies
Both. Amberlite MB3 and the combination Amberlite IR-120 followed by
Amberlite IR-U5 were tested for removal of the hydrochloric acid and
other inorganics in the solution of acid-soluble color bodies. In both
cases, large amounts of the color were retained by the resin.
All of the acid-soluble color was removed from the strongly acid solu-
tion with carbon (Draco), and there was some difficulty in filtering the
carbon. Moreover, the sorbed color could not be removed completely from
the carbon. Thus, neither ion exchange nor carbon seemed promising for
separation of acid-soluble color bodies from the inorganic constituents.
Finally, it was found that a large portion of the acid-soluble color
bodies could be sorbed on Amberlite XAD-2 (Rohm & Haas Co.) and could
be removed by eluting the resin with 50 percent ethanol. Most of the
color was sorbed at the top of the column from the strong acid solution,
but it moved slowly down the column as the excess acid was washed from
the column. The acid passed through the column faster than the color,
and most of the latter remained on the column when essentially all of
-the acid had been washed out. Additional color bodies were recovered by
concentrating the aqueous solution and the washings which passed through
the column, and then adding the concentrate to a smaller column of XAD-2.
The sorbed color was readily removed by eluting the columns with 50 per-
cent ethanol.
Paper Chromatography
Following preliminary experiments, 0.202 g of untreated freeze-dried
color bodies was dissolved in 3.2 ml water and the solution was applied
as evenly as possible to 8 strips of Whatman 3MM filter paper (23 cm x
28 cm). Thus, each strip carried approximately 0.0252 g of material.
The strips were air dried overnight and were developed in an apparatus
for des-cending chromatography. Chromatograms were developed in a mixed
solvent designated herein as BWA, butane water ascetic acid,
100:33:15. In about 2 hours the solvent had traveled 19 cm from the
starting line. There was considerable streaking, but four more-or-less
distinct brown-colored bands were present with additional brown-colored
material at the solvent front and at the starting line. The papers were
dried and were sectioned into seven bands or zones for subsequent elu-
tion.
The corresponding zones from 6 to the 8 original strips, equivalent to
0.152 g of the total, 0.202 g, were eluted with 50 percent aqueous ethyl
alcohol.
The above procedure was repeated with an untreated sample which had been
treated with an ion exchange resin, Amberlite IR-120, to remove the
60
-------
^i°n8' ^ C*romat°grams streaked or channeled badly, and no further
work was done with this method of separation.
Color Measurement
Color was measured according to the platinum cobalt standard method of
the American Public Health Association (APHA)9. The- only modification
of the method was the use of a noncarbonate buffer for pH adjustment to
7.6. It was necessary to have color values at a constant pH of 7.6,
because color was found to be pH dependent. Most natural waters have a
pH range close to 7.6.
It should be noted that the color unit is a measure of color intensity.
When it has been necessary to refer to the total amount of colored mate-
rial in a solution this has been called "total color" and is the product
of the color units and the volume of the solution.
Absorbance Measurement
The samples used for color measurement were also used for absorbance
measurement at desired wavelengths on the Beckman PU Spectrophotometer.
The values obtained were multiplied by the dilution factor to give
absorbance of the concentrated solutions. Absorptivity was calculated
by dividing the absorbance values by concentration in grams per liter.
Determination of Solids
Total solids were determined by evaporation of a measured volume of waste
at 105°C overnight. The resultant weight of solids was expressed in
milligrams per liter (mg/l) of waste.
Fixed and volatile solids were determined by igniting the total solids
at 600°C in an electric muffle furnace to constant weight, usually re-
quiring one hour. The loss on ignition is reported as mg/l volatile and
the residue as mg/l fixed solids.
Total Organic Carbon (TOG)
The Process Carbonaceous Analyser (Beckman & Co.) was used for this pur-
pose. Because this instrument gives only total carbon values, TOC was
determined by a modified direct method. The matters were further com-
plicated by very small quantities of the fractions. To conserve color
bodies, the majority of the specimens tested for TOC had been examined
61
-------
for color which necessitated dilution within the color range of the
platinum cobalt reference Uessler tubes .
For manual injections into the carbonaceous analyzer, an aliquot was
prepared as follows:
A 5-ml aliquot was transferred to a 30-ml glass beaker for a
5-ml volumetric flask. The pH of the specimen was adjusted
to 2.9 to 3.0 with a 0.1N HC1 solution (normally two milli-
liters were necessary). The acidified sample was rinsed with
distilled water into a 2.5 x 15 cm test tube, having a 2-ml
graduation mark, and the volume was reduced to 2.0 ml by
boiling over a gas flame. The boiled sample was then trans-
ferred back to the 5-ml volumetric flask and the test tube was
rinsed with 3 ml of pH 10 buffer (borax and sodium hydroxide)
and added to the volumetric flask to give a combined 5-ml pH
10.0 specimen. Prior to injection into the carbon analyzer,
the specimens were cooled to room temperature under the cold
water tap. Volume was checked after cooling and adjusted to
5 ml if necessary.
Twenty-three microliters of the specimens were injected at 3
to 5-minute intervals and an average reading was thus obtained
from which the "blank" reading was subtracted to give the TOG
value in mg/1.
The "blank" consisted of all the ingredients listed above minus
the sample and was handled in the same manner as the sample.
The analyzer was operated at 950°.C according to instructions in the in-
strument manual. In addition to the precautions listed in the operating
manual, the following precautions are recommended for accurate results.
a. The injection syringe should be checked often for burrs,
cracks, etc., which cause particles from the rubber cap
to drop into the combustion tube thus giving high readings.
b. A constant slow needle insertion and retraction is essen-
tial to prevent "popping" of the combustion chamber rubber
cap.
c. Combustion chamber rubber cap should be replaced often.
d. Tygon tubing close to the condenser, filters, and glass
combustion chamber dome should be cleaned often.
62
-------
Fractionation of Color Bodies
Two types of Bio-Gels (Bio Rad Co.) were used for this purpose. Bio-Gel
P-2 (exclusion limit 2600) and P-60 (exclusion limit 60,000) were hy-
drated in distilled water and separately packed in 2.5 x 200 cm and 2.5
x 100 cm glass columns, respectively. The complete apparatus used for
fractionation is shown in Figure 26.
The volume of the solutions used for fractionation was less than 3 per-
cent of the void volume of the column (void volume, Vo, = total bed
volume x 0-38). A measured quantity of the solution was added to the
top of the column. A glass fiber filter was used on the gel so that
upon addition of the solution, the gel surface is not disturbed. The
eluate was allowed to flow into an automatic collecting device and the
collector timer and the UV-cord recorder were started. When the solu-
tion dropped to just below the surface of the gel, one milliliter of
distilled water was added to the column and elution continued. When the
level was again slightly below the gel, more distilled water was added
and the column was then connected to the constant head water reservoir
through a filter and a flowmeter. The elution rate (0.2-0.3 ml/min) was
controlled by a teflon stopcock with a needle adjust. Fractions were
collected every 30 minutes. At the end of fractionation, which took
three to four days, the collected fractions were combined according to
the number of peaks on the UV recorded chart. The combined fractions
were freeze-dried and used for study. (Aliquots of the fractions were
taken for color, TOC, and absorbance before freeze drying.)
Determination of Molecular Weights
Molecular weights were measured by the sedimentation equilibrium method13.
In this procedure the centrifuge is run at an appropriate motor speed
for a period of time necessary to achieve an equilibrium condition (rate
of transport in one direction due to sedimentation balanced by the rate
of transport due to diffusion in the other direction). Having achieved
this condition, the technique requires the accurate measurement of the
solute concentration distribution throughout the cell. The equilibrium
condition is a practical one in which the concentration distribution does
not change with time within the measuring experimental errors. Inter-
ference optics provides an accurate photographic record of concentration
change from one position in the cell to another. A separate synthetic
boundary run determines the initial concentration in terms of a total
interference fringe shift.
Other data needed to compute molecular weights are rotor speed, tempera-
ture, partial specific volume of the solute, and density of the solution.
The densities of the solutions were measured according to the method de-
scribed by Bauer16 and plotted against their respective concentrations
63
-------
I
30 cm Head
50
Approx. Scale! I mm = I cm
Water Reservoir
50 cm
v LD*^*^-Penton Coupling w/Teflon Solv-Seal
Filter
Flowmeter
Bio*Gel Ghromotographic Columns
100 cm
--2.5 cm I.D.
Teflon
Valve
UVl-Cord Monitor
UVI-Cord Recorder
Automatic Collector
Teflon Stopcock
w/Needle Adjust
Figure 2.6. Diagram of Gel Permeation Chromatography Apparatus
-------
in g/ml._ A straight-line plot was developed and the partial specific
volume, V, was calculated from the straight-line relationship using
Equation (l). B
where
x = concentration, g/ml
do = density of solvent
d = density of solution
A computer program (MOLWT) [a modification of the program by Teller17]
was used for calculating the weight average molecular weights.
Disk Electrophoresis
The techniques and apparatus used were as described by Davis"11* with
slight modifications.
The apparatus consisted of two PlexLglas (3/8-inch) buffer vessels (l6.5
cm diameter and 9-0 cm deep) each with a centrally located electrode.
The bottom of the upper vessel had 12 equally spaced holes along a bot-
tom circumference. Bored out serum stoppers in these holes accept 5 x
100 mm glass tubes (gel columns). This buffer vessel was supported
above the other so that the lower ends of the gel columns extended about
1/k inch below the surface of the buffer in the lower vessel. Any bub-
bles formed on the gel column ends were removed. The power supply was a
RECO Model E 800-2, 750 volts, 200 ma maximum output.
Glass tubes (5 x 100 mm) were mounted with rubber caps in a rack and
l.U-ml small pore gel (separation gel) solution added to each followed
by a water layer to insure a flat gel surface. After polymerization
(30 minutes) the water was removed and the gel surface was washed with
large pore spacer or stacking gel. Spacer gel (0.1 ml) was added, over-
lay ed with water and photopolymerized for 30-lt5 minutes. After removal
of the water layer, 0.1-ml colored sample (0-5 mg in Uo percent sucrose)
was added. Buffer was then layered carefully to fill the tubes com-
pletely. The tubes were mounted in the grommets of the upper vessel,
buffer was then added to the vessels and electrophoresis started.
Length of the small pore separation gel was 7-2 cm.
Two preliminary runs were made. Untreated acid-insoluble sample Fraction
A 1-2 was run at 0.0625, 0.125, 0.25, 0,5, 1.0, and 2.0 mg per tube.
This sample was also run at 0.5 mg per tube with gel concentrations of
2.5, 5.0, 7.5, 10.0, 12.5, and 15-0 percent. At the higher monomer con-
centrations there was a general "smear" of material trailing the main
single band; however, no other discrete bands were visible. In subse-
quent runs, based on these results, a "normal" 7-5 percent gel was used
65
-------
with 0,5 mg sample per tube. Also, all samples vere run at UOO volts,
3^ ma for 60 minutes at room temperature. Following electrophoresis,
the distance from the top of the separation gel in the middle of the
colored band was measured and electrophoretic mobilities were calculated
according to Ornstein15.
Pyrolysis-Gas Chromatography
Selected samples of color bodies from dilute waste liquor were subjected
to pyrolysis-gas chromatography. The conditions were as follows:
Column: 20 percent Carbowax; 5 ft x 1/8 inch
Initial temp 75°; final temp 225°
Rate 10°/min
Detector: Hydrogen flame ionization
Temp 265°
Injector: Temp 225°
Carrier gas: Helium at 30 ml/min
Pyrolysis: 9-5 amp for 12 sec to produce a maximum temp of 650°..
Sample Amount Hydrolyzed, mg
Indulin C 0.39
Untreated acid-insoluble fraction
A 1-2 0.36
A U-5 0.30
B-C 0.37
D-K 0.35
Lime-treated acid-insoluble fraction
A 1-2 0.1*0
Untreated acid-soluble fraction
A 1-3 0.38
Lime-treated acid-soluble fraction
A 1-7 0.39
Particles of suitable size and density for proper loading of the pyroly-
sis apparatus were prepared from the fluffy freeze-dried solids. A small
droplet of water was placed on a microscope slide, the fluffy solid was
carefully added to the droplet until a heavy paste was formed. The paste
was dried in the air to a brittle solid from which suitable pieces were
selected for the pyrolysis-GLC. The chromatograms are shown in Figure
25.
66
-------
SECTION VIII
ACKNOWLEDGMENTS
Ihe support of the President of The Institute of Paper Chemistry, Mr.
John G. Strange, is acknowledged with sincere thanks. Mr. John ₯.
Swanson, Director of the Division of Natural Materials and Systems of
the Institute, was Project Director. Dr. Harder S. Dugal, Research
Associate of the Institute, was Project Leader and carried out much of
the work himself and coordinated the work of others on this project.
Dr. Marion A. Buchanan and Mr. Edgar Dickey were responsible for certain
phases of isolation and characterization work. Portions of the experi-
mental work were conducted by Messrs. Norman Colson, John Carlson, and
Lowell Sell each of whom contributed to the work in the area of his
specialty. Dr. Robert M. Leekley, Dr. Donald C. Johnson, and Mr. Carl
Piper contributed through valuable suggestions and consultation.
Mr. Charles L. Davis, Jr., Pollution Control Director of Interstate
Paper Corporation, and his staff periodically collected the samples of
colored waste which were studied and contributed useful information
about their lime treatment process.
The support of the project by the Office of Research and Monitoring,
Environmental Protection Agency, and the help provided by Mr, Edmond P.
Lomasney, Dr. James D. Gallup, and Mr. George R. Webster, the Grant
Project Officer, is acknowledged with sincere thanks.
67
-------
SECTION IX
REFERENCES
1. National Council of the Pulp and Paper Industry for Mr and Stream
Improvement (NCASl), Tech. Bull. 157 (1962).
2. Le Compte, A. R. Tappi, >£, no. 12, 121A (1966).
3. Davis, C. L. , Jr. Tappi, 52, no. 11: 2132 (1969).
U. Berger, H. F. and Brovn, R. I. Tappi, i|2_, no. 3: 2^5 (1959).
5. Smith, D. R. and Berger, H. F. Tappi, 51. no. 10: 37A (1968).
6. Dence, et_ al. NCASI Tech Bull 239 (1970).
7. GoldschMd, L. 0. In Sarkanen and Ludwig's book "Lignins Occur-
rence, Formation, Structure and Reactions." p 256-258. Wiley
Interscience, 1971.
8. Schachman, H. K. Reprint from Methods in Enzymology. Vol. IV.
Academic Press, Inc., New York, N. Y. (1957).
9- Standard Methods. American Public Health Association, 12th ed. ,
p 129 (1965).
10. Goring, et_ al. Pulp Paper Mag Can, 65, T127 (196U).
11. Goring, et_ al. Tappi, 50. no- 11: 5^8 (1967).
12. Borchardt, LeRoy G. and Piper, Carl V. Tappi, 53, no. 2:257 (1970)
13. Chervenka, C. H. A Manual of Methods for the Ultra centrifuge.
pp 1*2-55 5 Beckman Instruments, Inc. (1969).
Ik. Davis, B. J. Annals of the New York Academy of Sciences, 121: hok
(1964).
15- Ornstein, L. Annals of the New York Academy of Sciences, 121: 321
(196U).
2.6. Bauer, N. Determination of Density. In_ Weissherger's Technique
of Organic Chemistry. Physical Methods. 2nd ed. Vol. 1. Part 1.
pp 25^-96, Interscience, New York (19^9)-
17. Teller, D. Sedimentation Equilibrium for Macromolecules.
University of California, Berkeley, Calif. (1965)-
69
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SECTION X
PUBLICATIONS
1. Dugal, Hardev S., Swanson, John W., Buchanan, Marion A.', and Dickey,
Edgar E. Chemical and Physical Nature of Color Bodies in Kraft
Mill Effluents Before and After Lime Treatment. AIChE Sixty-fourth
annual meeting, San Francisco, California, Nov. 2-'8~Dec. 2, 1971,
Paper l6C.
This paper was presented by Dr. H. S. Dugal at the AIChE 6^th annual
conference in San Francisco.
71
-------
SECTION XI
APPENDICES
I. Fractionation of color todies: material balance based on color and
TOC.
II. Detailed sugar analysis of untreated and lime-treated wastes.
73
-------
APPENDIX I
FRACTIONATTOlf OF COLOR BODIES
(Material balance based on color and TOC)
Untreated Time '
Decker Waste
(-86)
Color (100)
TOC [100]
Acid Treatment
V
1 Acid- Acid- '
insoluble soluble
My < 30,000 My < 5000 Loss
(63) (30) | (7)
[59] [18] [23]
^ y
FRACTIONATION
4, 4,
P-6o Al (11.7) [6.8] Al (0.8) [0.60]
Bio-Gel A2 (19-9) [9-7] A2 (1.2) [1.00]
A3 (9.8) [3.0] A3 (1.7) [0.87]
Al* (3.8) [1.8] Alt (2.6) [0.86]
A5 (2.1) [1.0] A5 (1.8) [0.96]
A6 (0.1*) [0.10]
A7 (O.U)[6.17]
P-2 A (1*9.8) [32.8] A (9-9) [*».2]
Bio-Gel B (7.6) [6.5] B (7.5) [5-0]
C (1.9) [1.1] C (3.1*) [2.8]
DE (1.8) [1.5] D (3-7) [1-8]
F (2.5) [5-0] E (3.2) [2.0]
G (0.6) [1.5] F (1.6) [1.0]
HJ (1.0) [2.3] G (1.8) [1.0]
K (1.5) [!*-7] H (0.5) [0.2]
L (O.lt) [0.2] J (0.2) [0.07]
M (1.7) [0.6]
treatment, ^-^ff
[-57.2] (lU) [1*2.8]
Treatment
1 Acid- Acid- '
insoluble soluble
My < 5000 My < 5000 Loss
(3.7) | (7-7) 1 (2.6)
[3.6]! [10.2] 1 [29]
FRACTIONATION
4, 4,
Al (0.67) [0.22) Al (0'.07) [0.06]
A2 (0.38) [0.13-] A2 (0.13) [0.25]
A3 (0.26) [0.26] A3 (0.36) [0.32]
Al* (0.1*2) [0.31]
A5 (0.1*8) [O.lt*]
A6 (0.07) [0.03]
A7 (0.02) [0.01]
A (1.2) [0.68] A (1.9) [2.0]
B (0.3) [0.2l»] B (0.7) [1.1]
C (O.l8)[0.22] C (1.5) [2.5]
DE (O.U)[0.35J D (0.7) [1.6]
F (0.5) [0.71*] E (1.6) [1.9]
G (O.ll*)[0.1l] F (0.2) [0.37]
HJ (0.2l)[0.27J G (0.6) [0.36]
K (O.U) [0.5l*] H (0.1) [0.19]
L (0.07)[0.05] J (0.06)[0.13J
M (0.17)[0.15J K (0.3) [0.08]
L (O.OU) [0.037]
M (0.02)[0.0l»]
All values calculated on the basis of untreated Decker waste taken as 100.
Color values are shown in parentheses and TOC in brackets.
Color bodies were first fractionated on Bio-Gel P-2 to give Fraction A-M.
Fraction 'A1 from P-2 was further fractionated on Bio-Gel P-60 to give Fractions A1-A7.
My = weight average molecular weights.
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APPENDIX II
DETAILED SUGAR ANALYSIS OF UNTREATED AND LIME-TREATED WASTES
Sugarsa
Sample Fractions
Untreated Waste
Acid-insoluble
Fraction Al-2
A3
AU-5
B-C
D-K
M-T
Acid-soluble
Fraction Al-3
AU
A5-6
B-J
Lime-Treated
Acid-insoluble
Fraction Al-2
Acid-soluble
Fraction Al-T
B-F
Indulin 'C'
Rhamnan
0.11
0.018
_
__
0.13
0.026
__
0.077
O.OU7
o.oUo
o.Uo
0.15
M
O.OlU
__
Arab an
0.16
0.31
0.68
0.22
_»
O.Olt
_
0.28
0.35
o.Uo
0.30
0.59
0.13
0.37
0.058
0.32
0.9l*
0.51*
Xylan
0.29
0.13
0.39
O.U3
0.28
0.17
0.035
0.38
3.0
0.5
1.2
0.78
0.80
0.09
0.81
0.063
1.18
3.1
0.96
Hannah
0.13
0.19
__
__
__
0.10
__
0.11
O.U7
__
__
0.27
2.30
__
O.U8
0.20
Galactan
0.16
0.12
0.10
0.03
__
__
0.007
O.Ul
0.057
0.27
o.oik
__
__
O.UO
0.65
0.18
Glucan
0.065
O.Ul
0.95
0.26
0.26
0.089
0.16
O.lfc
O.Ul
0.8U
0.28
U.20
0.081
0.008
__
1.7
0.061
O.llt
1.0
0.2
Total
1.51
1.60
2.12
0.9U
0.67
O.U2
0.20
0.26
2.69
k.2k
1.28
6.10
1.72
2.92
2.39
2.88
0.18
2.86
5.89
1.88
0.15 0.21 0.7 0.008 1.07
on respective o.d. solids.
U. S. GOVERNMENT PRINTING OFFICE : I 973 51'j-r 53 (191)
T5
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i 1 Accession Number
w
2
Subject Field & Group
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
The Institute of Paper Chemistry,
Division of Natural Materials & Systems
Title
KRAFT EFFLUENT COLOR CHARACTERIZATION BEFORE AND
AFTER STOICHIOMETRIC LIME TREATMENT,
jo]
Authors)
Swanson, John W.,
Project Director
Dugal, Hardev S.,
Project leader
Buchanan, Marion A.
Dickey, Edgar E.
Project Designation
EPA, WQ Contract No. 120!»0 DKD
Note
22
Environmental Protection Agency report
number, IPA-R2-73-141, February 1973.
Descriptors (Starred First)
*Pulp Waste, *Waste Treatment, Industrial Waste Treatment, Pollution
Abatement, Waste Water, Effluents, Water Reuse
Identifiers (Starred First)
*Lime Treatment, *Kraft Colors, *Kraft Effluent, *Decker Effluent, *Kraft Decker
Effluent, *Molecular Weights, Chemical Analysis, Color Characterization, Color Isolatior
Abstract
The lime-treatment process was found to remove on an average about 86 percent
of the color, 57 percent of the total organic carbon, and IT percent of total sugars
from the waste effluent during the period of approximately 15 months over which the
samples were collected. No appreciable change in chloride content was noticed.
The "weight average" molecular weights (M^) of the untreated acid-insoluble
fractions varied from < UOO to 30,000 and of the untreated acid-soluble, lime-treated
acid-insoluble, and lime-treated acid-soluble fractions from < hOO to 5000.
The study shows that color bodies having an apparent M,, of < UOO are not removed
by lime treatment and those having M^ of 5000 and above are completely removed. The
intermediate range of Mw 1*00 to 5000 apparently undergoes partial removal.
Infrared spectroscopy data indicate that the acid-insoluble color bodies (high M^)
contain a high proportion of conjugated carbonyl groups where conjugation with an
aromatic ring is probable. The acid-soluble fractions (low M^) seem to contpin non-
conjugated carboxyl groups and may be associated with carbohydrate material. However,
color bodies are found to be aromatic in nature (partially degraded lignin), possess a
negative charge, and exist primarily as soluble sodium salts in aqueous solutions.
The color bodies which are not removed by lime treatment have low M^ high non-
conjugated carboxyl groups, some ligninlike character, and seem to be associated with
colorless carbon compounds.
Abstractor
Dugal, Hardev S.
*Kie Institute of Paper Chemistry
WR-102
WRSIC
(REV, JULY 1969J
SEND. WITH COPY OF tSOCUMENT. TOl WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.3. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
* CPO; Ifl70-3fr«~930
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