EPA-660/2-75-016
JUNE 1975
Environmental Protection Technology Series
Application of Exchange Resins for
Treatment of Textile Dye Wastes
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Corvallis, Oregon 97330
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. 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
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY STUDIES series. This series describes research
performed to develop and demonstrate instrumentation, equipment
and methodology to repair or prevent environmental degradation from
point and non-point sources of pollution. This work provides the
new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily 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.
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EPA-660/2-75-016
JUNE 1975
APPLICATION OF EXCHANGE RESINS FOR
TREATMENT OF TEXTILE DYE WASTES
by
Allison Maggiolo
J. Henry Sayles
Bennett College
Greensboro, North Carolina 27420
Project Number R802586
Program Element 1BB036
ROAP 21 AZT, Task 006
Project Officer
Thomas N4 Sargent
Southeast Environmental Research Laboratory
National Environmental Research Center
College Station Road
Athens, Georgia 30601
Deputy Project Officer
Arthur Burks
Southeast Environmental Research Laboratory
National Environmental Research Center
College Station Road
Athens, Georgia 30601
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
US ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
For >ale by the Superintendent of Documents, U.S. Government
Printing Office, Washington, D.C. 20402
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ABSTRACT
The objective of this study was to investigate the use
of ionic and neutral polymeric resins to remove and
recover textile dye wastes before such wastes are fed
into rivers and streams.
Initially, synthetic azo-dyes with various functional
groups were used that would represent a broad spectrum
of textile dyes. Then, various types of actual plant
dye wastes, which included all the additives were in-
vestigated. These dye wastes consisted of direct, acid,
basic, vat and dispersed dyes. They were screened
against various commerically available ionic and neutral
resins to see which resin or resin combination would
remove them most efficiently. The data obtained in this
investigation indicate that all except dispersed dyes
could be removed to give a colorless effluent. There-
fore, considerable investigation was focused on dispersed
dyes. The complete color removal of dispersed dyes was
accomplished with a neutral resin column followed by a
weak base column.
These results warrant further investigation to determine
whether this laboratory success can be translated to
commercial utilization.
This report was submitted in fullfillment of Grant Number
R802586 by Bennett College, Greensboro, N. C., under the
sponsorship of the Environmental Protection Agency. Work
was completed July, 1974.
ii
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CONTENTS
Sections
iii
Page
I Conclusions 1
II Recommendations 2
III Introduction 3
IV Experimental Phase 5
V Discussion 10
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FIGURES
No. Page
1 Dye removal column by gravity feed 6
2 Methanol regenerant above column bed 8
3 Mutihead pump drive system with feeds
to columns 9
4 Visual comparison of various best runs
of color removal for dispersed dyes 31
5 Colorless effluent emerging in flask
from XAD-7 over Duolite A-7,
runs #40 to 46 32
iv
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TABLES
No« Page
1 Phase 1 - Type of Resin 12
2 Phase 1 - Azo-Dye Removal 13
3 Phase 2 - Removal of Plant Dyes 15
4 Phase 3 - Conditions of Dispersed Dyes 18
5 Phase 3 - Removal of Dispersed Dyes 21
6 Phase 4 - Resin Columns in Tandem with 100%
of Mixed Dyes 30
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ACKNOWLEDGEMENTS
The authors are Indebted to Sy Hall, Arthur Toompas and
Tom Alspaugh, Central Research and Engineering, Cone
Mills. They provided valuable background information on
exchange resin waste treatment and supplied plant dye
wastes.
The assistance given by Howard Dixon, Manager of Dyeing,
Sellers Manufacturing Dyeing and Finishing, in supplying
all the various types of dye waste samples for Phase 2
of this report is greatfully acknowledged.
A major contribution was given by William Simpson, Manager
of Dyeing, Glen Raven Hosiery Mills. He not only provided
all the dispersed plant dye exhaust samples, but also
rendered invaluable technical assistance related to their
plant dyeing operation.
Special thanks are due to Thomas N. Sargent, Arthur Burks
and Dr. Samuel Karickhoff, personnel, of the Southeast
Environmental Research Laboratory for their technical
suggestions, literature and arranging for contacts with
their professional colleagues working in this field.
Particular appreciation is accorded to Student Assistants
Rita Nzeribe, Janice McLean and Nanetta Lowe for their
able research assistance. Especially to Miss Lowe are we
indebted for her tireless efforts and assistance in
obtaining the experimental findings.
vi
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SECTION I
CONCLUSIONS
Highly colored azo-dyes were completely removed by basic, neutral
and one very weak acid polar resin. However, if the basic resins
were in the (OH) hydroxide basic form instead of the (CI) chloride
salt form, the dyes were not removed. These same azo-dyes were
not removed by weak and strong acid resins.
The main types of actual dye wastes (direct, acid, vat, sulfur,
reactive and dispersed) were screened against the various types
of resins. The results indicated that all these dyes except
dispersed dyes could be removed to give a colorless effluent.
The complete color removal of dispersed dyes was accomplished with
a neutral macroreticular resin followed by a weak base resin.
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SECTION II
RECOMMENDATIONS
It is recommended that an automatic bench scale pilot unit running
continuously from 6 to 15 gal/hr be demonstrated. Probably two (2)
different resin columns in series would take care of the majority of
types of plant dye waste. As far as practical, the following should
be automatic: pumps, adsorption, back washing, elution and
regeneration. It should include a semi-continuous solvent stripping
unit and continuous spectrophotometer monitor at the column bed
discharge to determine when to switch to the regeneration cycle when
color of effluent reaches a pre-determined set point. The flow rates,
amount of resin and size of equipment should be at a large enough
scale to determine the following: (1) the technical success and (2)
capital operating costs of a large pilot and full scale plant of the
same nature.
At least three different textile mill wastes with three different
types of dyes (direct, dispersed and ionic) should be used.
The following three (3) technical goals are recommended:
1. Remove all the types of dispersed dyes as has initially been
done with the few used in this study. Until this
investigation, little success has been reported in the
removal of dispersed dyes by carbon and exchange resin
adsorption or activated sludge treatments.
2. Investigate dye wastes that come from dyeing natural fibers
(cotton, wool) or the r blends to see if they contain enough
loose short fibers to clog the resin columns and render them
inoperable. If so, see if this can be avoided.
3. Reclaim and re-use the dyes that have been adsorbed from the
waste. Where the dyes can't be re-used, blend them as oily
solids directly into the plant furnace system as fuel.
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SECTION III
INTRODUCTION
BACKGROUND
One of the major problems faced by the textile dyeing industry is the
pollution of streams by dyes. This type of water pollution is getting
to be a major concern. Highly colored industrial waste streams have
been considered to be undesirable, primarily due to their objectionable
appearance. Such streams are presently coming under stricter and more
specific pollution regulations. A rather high biochemical oxygen
demand (BOD) and chemical oxygen demand (COD) accompany the color due
to the presence of chemicals in the dye or added as carriers, leveling
and wetting agents or buffers to the textile dye bath. Dye waste often
contain organically-bound metals such as chromium and copper, that
can be toxic to the biological treatment systems as to vegetation
and micro-organisms. The same chemistry that gives fabric color-
fastness and resistance to bleaching, sunlight, and oxidation makes
these dyes similarly resistant to clean-up processes that depend
upon degradation as a means of decolorization.
Carbon adsorption has been used. Thermal regeneration of activated
carbon is generally accepted as a feasible means of restoring capacity.
Thermal regeneration requires transporting the carbon from the
decolorization column to a controlled-oxidation furnace,
labor to supervise the carefully controlled heating cycle, and
finally water quenching the hot carbon before reloading it back into
the column. Carbon losses are reported to be 5-10% due to oxidation
in the furnace and handling. In addition, where pre-metallized dyes
contribute organically-bound metals to the waste stream, thermal
regeneration of the activated carbon will often not restore its
original efficiency. The organics are burned off, but the metals
tend to "enamel" over the adsorption surface, making the carbon less
effective after only a few exhaustion cycles. "However, polymeric
adsorbents can be regenerated with a solvent, eliminating costly
thermal regeneration and the problems associated with thermal
deposition of metals.
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PHASES OF PROJECT
The project was conducted in four phases. The first phase was the
preparation of three standard azo-dyes with two, three, and four
anionic functional groups. These dyes were then screened against
anionic, cationic and neutral polymeric resins. The objective was
to determine which would most readily adsorb and remove what type
of azo-dyes from their aqueous 1.% solution.
The second phase was to investigate the removal of dyes from actual
dye wastes in which azo-dyes are often found. The dye wastes came
from direct, acid, dispersed, vat, sulfur, and reactive types of
dyeings. These various colored plant dye waste solutions were
eluted through glass chromatographic columns containing polymeric
adsorbent resins to see which resins would remove the dyes and give
a colorless effluent. Also investigated were the regeneration and
elution of the adsorbed dyes and the possible continuous re-use of
the resins without loss of dye removal efficiency.
The third phase was to investigate the removal of "dispersed dyes"
from textile dye waste. Until now, this had not been reported.
It is one of the key problems of the textile industries. Most of
all classes of possible adsorbent resins were tried.
The fourth phase was optimization and automation.
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SECTION IV
EXPERIMENTAL PHASE
PHASE 1 AND 2 - DYE SAMPLE PREPARATION AND EVALUATION
Semi-micro standard pyrex chromatographic 25 ml columns (10 mm I.D.
X 250 mm L.) with coarse glass frit discs were used.
All rates of flow for dye-liquors and all columns were held constant
at 1 drop per 5 seconds. Gravity feed was used throughout with the
same volume of swollen resin (17 ml) and same liquid height over the
resin. When necessary in a few cases the rate was held to same
1 drop/5 sec., by adjusting packing density, height of liquor or
stop-cock, see Figure 1.
The resin was used in the form supplied as noted in Table 1. Cation
resins (acid) were in the H+ form; anionic resins (basic) were in
OH~ or Cl~ form. Most of these commercial resins were 20-50 mesh.
Dye concentration for each of the 3 azo-dye liquors were made as
close as possible at 1%.
The total amount of dye liquor used until break through of the
color was the amount recorded. This gave a rating of the capacity
of each resin. This of course was only part of our objective, the
other was the determination of the ease of elution of the dye from
these resins and re-use of the resin at acceptable textile mill costs.
PHASE 3 - DISPERSED DYE REMOVAL
The three main areas developed are discussed 'in this phase.
FLOW RATES
It was convenient in the experiments to measure column flow rates in
drops/5 sec in order to control our experiments. Resin column flow
rates are usually expressed in bed volumes per hour. There were 10+1
drops in a ml. The rate was 1 drop/5 sec (70 ml/hr) for the 17 ml
volume of ion exchange resin. This was equivalent to four bed
volumes per hour. Similarly, 2 and 4 drops/5 sec were respectively,
eight and sixteen bed volumes per hour. These rates fall within the
range of accepted commercial practice for ion exchange usage.
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Figure 1. Dye removal column by gravity feed,
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COLOR NUMBER
The Perkin-Elmer Double Beam Spectrophotometer #124 was used to
determine the 3 highest absorption peaks of Glen Raven Hosiery Mills'
dye mix. The dye mix was the four dye formulas mixed in equal amounts.
These peaks were 520, 590 and 640 millimicrons. The Spectronic 20 was
set at these three wavelengths, and the average of these readings was
called the color number. This was an indication of absorption and was
based on distilled water being 0.0. However, any turbidity as well as
any color gave a higher value. The dye mix waste resulted in complete
absorbance a 2.0+ number (maximum instrument reading).
REGENERATION
To regenerate 51 ml of Permutit S-2, 50 ml methanol were used to remove
the dyes. Initially the methanol containing the dyes was dark and then
gradually became colorless as less and less dyes were left on the resin.
Then 100 ml of water were used followed by 50 ml of 1.0% HC1. Note the
dark color of the methanol regenerate above the column bed, Figure 2.
This was repeated for subsequent regenerations. Dowex 4022 (51 ml) used
50 ml of methanol, 75 ml toluene, 50 ml of methanol and 50 ml of water.
Almost all of the dye was removed by the 1st 50 ml of alcohol but the
resin became white upon using the toluene. Toluene complicated the
regeneration process because it is water insoluble. The subsequent
aqueous rinses bead up and don't wet the resin unless the remaining
toluene is completely removed by a water miscible solvent as methanol
above.
PHASE 4 - AUTOMATION AND OPTIMIZATION
This phase was to make the process more continuous and to find the
best resin combinations. A multihead pump drive feed system was set up
in single and double column tandem operation. This allowed the dye
waste to be fed continuously at a constant feed. The usual gravity-
manual feed was hard to hold at a constant rate of feed.
The multihead pumps, Figure 3, also permitted us to switch over to
the wash and regeneration with methanol cycles without any interruption
in time. Two different size glass columns, inside diameter 12 mm and
25 mm, length 600 mm and 400 mm, respectively, were used. The flow rate
for dye waste influent, wash and regeneration cycles were 2 ml/min,
0.5 ml/min, and 0.5 ml/min, respectively for the 12 mm ID column
packed with 30 ml of resin. Similarly, flow rates for the 25 mm column
packed with 70 ml of resin were 4 ml/min, 1 ml/min and 1 ml/min,
respectively.
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Figure 2. Methanol regenerant above column bed.
8
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Figure 3. Multihead pump drive system
with feeds to column.
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SECTION V
DISCUSSION
PHASE 1
Three (3) azo-dyes were synthesized with an increasing number of acid
functional groups and screened against fifteen (15) ionic and neutral
polymeric resins. The formulas of the three dyes are as follows:
Na03S-
HOOC-
II
HOOC
III
Dye I has only two (2) functional groups, -OH and NaOoS-. Dye II has
three (3) functional groups, -OH, -COOH and NaOgS-. It is more acidic
because the carboxylic acid group has been added. Dye III has four (4)
functional groups, -OH, -COOH and two (2)
The removal of azo-dyes by passing synthetic dye solutions through the
various types of resins until break thru of some of the dye is shown in
Table 2. The three synthetic dye solutions were made to 1.0% by weight
of each dye. This was about 10 to 20 times the concentrations of these
types of dyes that would actually be left in solution after a typical
plant dye had been exhausted in dyeing the textile fabric or yarn.
10
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In Tables 1 and 2, it is clearly evident that five out of six different
types of basic resins (both strong and weak base types) were efficient
in removing all three types of azo-dyes. From 30 to 40 ml of the dye
solutions could be passed through the basic resins before there was
any break thru of the dyes. However, it was necessary that these
basic resins be in the hydrochloric acid salt form. This is the (Cl)
form as shown in Table 1. If the resin was changed to its (OH) form
by washing it with 2.0% sodium hydroxide solution, it did not remove
the azo-dye from solution. The salt form of Duolite A- 7 was washed
with 2% sodium hydroxide solution and then with distilled water to
remove excess base. The (OH) form of Duolite A-7 did not remove the
color of the azo-dye solution. This was apparently the reason why in
runs 6, 7, and 8 the resins, in the (OH) form, did not remove the azo-
dyes.
The failure of the three resins in their (OH) form to remove the azo-
dyes can be explained in terms of pH and ionic attraction. The basic
polyamine resin in its hydrogen chloride salt, is represented as Poly-
mer-NR2HCl. The carboxylic or sulfonic acid group of the soluble dye
reacts with the polymeric resin (Polymer-NR2) via ion-exchange as
follows: ,
(insoluble) Polymer-NR2H + Azo-dye-S03 Na (soluble) -
"Cl +
NaCl + (insoluble) Polymer-NR2H
If the column pH is low (<5) the "soluble" salt form of the dye can be
converted into the "insoluble" acid form prior to ion exchange in the
resin. One of the strong base resins, Run #3, Dowex-11, was not very
efficient. Since all the other base resins in their salt form were
efficient in azo-dye removal, no further time was spent with Dowex-11.
As seen in Runs #9 and 11, Table 1 and 2, the complete removal of the
azo-dyes from their solutions by neutral resins and very weak acid
resins can be best explained by the mechanism (2) of physical adsorption
described below. It has been reported in Dr. David C. Kennedy's paper,
"Molecular Polymeric Adsorbents, " Ind. Eng. Chem. Prod. Res. Develop,
Vol. 12, No. 1, 56-61, 1973.
MECHANISMS OF DYE REMOVAL
There are two (2) mechanisms of removal of dyes by exchange resins.
Mechanism one (1) is the dye being strongly held by the ionic forces
of an ionic resin. As shown above the cationic strong basic resin
strongly attracts the anionic sulfonate azo-dye.
11
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Table 1. PHASE 1 - TYPE OF RESIN
Run #
Type
1
strong base
2
strong base
3
weak base
4
weak base
5
weak base
6
weak base
7
weak base
8
weak base
9
neutral
10
neutral
11
slight acid
12
weak acid
13
strong acid
14
strong acid
15
strong acid
Resin
Permutit
S-2
Permutit
S-2
Dowex-11
Duo lite
S-37
Duolite
S-37
Dowex
WGR
Amberlite
XE-275HP
Amberlite
IR-48
Amberlite
XAD-7
Dowex
4022
Duolite
S-30
Amberlite
IRC-50
Bio-Rex
40
Dowex
50W-X4
Amberlite
IR-120
Source
lonac
lonac
Dow
Nopco
Nopco
Dow
Rohm &
Haas
Rohm &
Haas
Rohm &
Haas
Dow
Nopco
Rohm &
Haas
Bio-Rad
Dow
Rohm &
Haas
Mesh
16-50
16-50
20-50
16-50
16-50
20-50
Unavailable
Unavailable
20-50
20-50
Unavailable
Unavailable
200-400
20-40
20-50
Form
Cl
Cl
Cl
Cl
Cl
OH
OH
OH
Not
applicable
Not
applicable
Unavailable
H+
H+
H+
H+
12
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Table 2. PHASE I - AZO-DYE REMOVAL
Run //
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
ml at break-thru for dyes
Dye I Dye II Dye III
40
40
4
30
31
6
0
0
35
0
36
0
0
0
0
42
41
4
32
32
8
0
0
38
0
39
0
0
0
22
43
42
6
34
34
9
0
0
41
0
42
0
0
0
29
Visual observations
of color removal
Good
Good
Poor
Good
Good
Poor
Could not handle,
gave voids
No
Good
No
Good
No
No
No
Dye I-no, Dye II-fair,
Dye. Ill- good
13
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This resin-dye complex is split by strong base solution (2-5% NaOH)
which is a stronger base than the basic resin. The equation for the
desorption of the dye from the resin and solublization in the
regenerated effluent would be as follows:
(insoluble) Polymer-NR2H + NaOH (solution) ^ (1)
~03S-Azo-dye
(soluble) Na03S-Azo-dye + (insoluble) Polymer-NR2
Mechanism two (2) is the hydrophobic resin's removal of soluble organic
dyes from aqueous solutions via weak Van der Waal's physical forces.
For details of this mechanism see Dr. Kennedy's paper mentioned above.
For all practical purposes the attraction of the hydrophobic resin is
enough to pull the dyes out of their aqueous solution. An example is
Amberlite XAD-2 (styrene-divinylbenzene polymer) which is a macroreti-
cular hydrophobic resin that adsorbs sodium anthraquinone sulfonate
from its aqueous solution. To regenerate these polymeric non-ionic
adsorbents, the dye-molecule-adsorbent force must only be overcome by
the solvating power of the organic solvent on the dye molecule. The
dye molecules are not strongly bound (as in the case of ionic attraction,
mechanism 1) so that solvent regeneration with methanol is feasible.
However, the binding forces are strong enough to allow the adsorbent
to remove the dyes.
Weakly basic or acid resins may act also by adsorption via mechanism
(2) as well as by its ionic mechanism (1). Dr. David C. Kennedy
et al, in a Rohm & Haas company publication, reported a two step
regeneration process for weak acid or basic resins, A New Adsorption
Ion-Exchange Process For Treating Dye Waste Effluents. This two step
regeneration works best with soluble ionic dyes, first using the
respective acid or base to return the resin to the non-ionized form
(H*~ or OH**), followed by methanol elution. It is postulated that by
first rinsing with acid (for the weakly acid resins) or base (for the
weakly base resins) the weak ionic force between the dye molecule and
the resin is broken. All that holds the dye to the resin is the weak
Van der Waals force. Rinsing with methanol solvates the dye molecule
and frees it from the resin. However, in our main work which was
involved with removal of dispersed dyes, we only had to regenerate the
weak base resin, Duolite A-7, with methanol.
PHASE 2
The results as shown in Table 3 were quite encouraging in that all the
dyes from ten (10) different types of actual plant dye wastes taken
from three different textile mills were removed except the dispersed
dye waste (B-C). Sellers Manufacturing Dyeing and Finishing dye
wastes were selected because they use a variety of different
classes of dyes: Reactive, Direct, Vat, Sulfur and Union-Wool (acid).
14
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Table 3. PHASE 2 - REMOVAL OF PLANT DYES
Dye #
1-B
2-B
3-B
4-B
' 5-B
C.M.
B-C
11-A
7-A
9-A
Type
Reactive
Reactive
Direct
Vat
Sulfur
Mixed
Dispersed
Reactive
Reactive
Union
Dye
PH
10.3
11.1
6.5
12.6
11.6
8.3
7.4
10.4
11. 0
4.5
Permutit S-2
break final
ml pH
25a
25a
25a
25a
25a
250
200b
300
300
a
5.7
5.7
6.0
6.1
5.9
4.0
4.8
4.3
4.2
Duolite A-7
break final
ml pH
75
100
92
128
a
175
200b
178
192
a
5.7
5.6
5.5
9.9
5.5
4.8
4.2
5.6
Duolite S-37
break final
ml pH
a
a
128
92
a
150
200b
250
325
100
5.2
7.4
4.4
4.5
4.2
5.7
5.0
Duolite S-30
break final
ml pH
25a
25a
25a
25a
25a
275
a
350
375
100
5.7
5.7
5.8
9.8
5.9
4.0
4.1
3.9
5.2
aRan out of dye waste.
^Persistent pink color came thru from start,
then deeper color at break.
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Cone Mills (C.M.) gave us their worst conglomerate which was a mixture
of Direct, Indigo, etc. Cotton dyes. Glen Raven Hosiery dyeing waste
(B-C) are singularly interesting because only one type of Dispersed
dyes are used throughout the nylon hosiery dyeing industry. All nine
wastes were the dye baths at the end of the dyeing cycle without any
dilution with rinses or waste water. Cone Hills (C.M.) wastes were
diluted by their other plant streams. The four resins used to screen
these ten wastes were chosen from Phase 1. They were: strong base
(Permutit S-2), weak base (Duolite A-7) and (Duolite S-37) and very weak
acid, almost neutral (Duolite S-30). From 100 to 300 ml of dye exhaust
were retained by 15 ml of the four resins until break-through, according
to what resin and dye were used. This means that 7 to 20 bed volumes of
dye liquor may be run through any one of the above four resin columns
before the column bed would have to be regenerated. In the cases where
the breakthrough amount of dye influent is noted as 25 ml, the liquor
ran out before the actual breakthrough of any color. This same dye
waste used with reactive and direct dye waste did not breakthrough until
between 100 to 300 ml were passed. In regeneration, in almost all cases,
the combination of 20 to 30 ml of 2% sodium hydroxide solution followed
by 20 ml of wash water and then 20 to 30 ml of methanol between 20° to
40°C was sufficient to remove the dyes successfully. In some cases the
methanol or the 2% NaOH solution singularly was able to regenerate the
dye waste. Namely, methanol, 20 to 30 ml at 40°C removed dye waste,
2-B and B-C from Duolite A-7 and dye waste B-C and C.M. from Permutit
S-2. The 2% NaOH solution, 30 ml at 40°C and 50 ml at 20°C, removed
C.M. waste from Duolite A-7.
Table 3 shows that 200 ml of Glen Raven's dispersed dye B-C were added
until a decided breakthrough of color. However, from the beginning with
all three resins there was always a persistent pink color in the
effluent.
Cone Mills' (C.M.) dye was retained until 175, 250 and 275 ml passed
through A-7, S-2 and S-3 resins, respectively, before breakthrough of
color.
PHASE 3
This phase was with the dyeing waste waters of Glen Raven Mills, Alta-
mahaw plant. They have a dispersed nylon hosiery dyeing operation.
Assistance from Ciba-Geigy and Glen Raven Mills established the names,
C.I. (Color Index Number) and structural formulas of the main three
dyes used. They were: Cibocet Yellow 2GC (C.I. #11855), Cibocet Blue
BN (C.E.I. #61505) and Terasil Scarlet B (C.I. #11110). They blend
these along with others in different proportions to give standard dye
formulas which they use to give varying shades of beige, tan, brown, and
an off black mascara. Four of their standard dye formula wastes were
used, #334, #339, #515 and #541 and as a mix in equal proportions at
100% cone, or its dilution with water to 75% and 50%. Their dyeing
16
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formula is about 2 to 4% of dyes and 6% of an all in one non-ionic
compound which acts as a wetting agent, detergent, dispersant, and
antistat. These dyes are colored, particulate, very fine suspensions.
Our results show the removal of all of the dyes gives a colorless
solution. The resin treatments remove all of the color but a faint
white turbidity persists. In attempting to use the Perkin Elmer 120
or the Spectronic-20 to put numerical values on the reduction of color,
the usual standard technique is to filter any turbidity whose presence
would increase the apparent color number. However, these particular
dyes can't be filtered without removing the remaining colored dispersed
dyes. Though the color numbers were recorded, samples were retained
of the original concentrated dye wastes, their serial dilutions and
subsequent ion-exchange treatment for evaluation of key successful
runs. However, we have in Table 5 described visually the extent of
color removal. In Phase 4, the optimization runs of this Phase 3,
Figures 4 and 5 show the total removal of color.
SUMMARY
Strong and weak acid and basic resins were used singly and in tandem.
The macroreticular neutral resin XFS-4022 was used by itself in
Phase 3. As shown in Tables 4 and 5, the order of efficiency of dye
removal as single resins was: (1) Dowex XFS-4022, runs #31 through //34;
(2) Amberlite IRC-50, weak acid, runs #35 and #36; (3) Amberlite IR-120,
strong acid, see runs #2,6,10,11, and 12; (4) Permutit S-l and S-2,
strong base, runs #3,4,7,8, and 9; (5) the least efficient were the weak
base resins, runs #29 and 30.
With two resins in tandem the most efficient combination of resins appears
to be when a strong base was over a strong acid resin column, Table 4 and
5, run #27.
DISCUSSION
Pretreatment of the resins have to be carried out according to specific
instructions from the manufacturer for that particular resin in order
for it to perform properly. The resins, being in different form or
treated differently, are subject to different volume changes. Dowex
4022 which is pretreated with methanol swells 10% and then stayed
constant. IRC-50, IR-120 and Permutit S-l increases 1/3 on pre-
treating with water and then stayed constant. Duolite A-7 does not
change with water but increases 10% on regeneration with methanol and
then stayed constant. If we diluted the mixed dye waste from 75% to
50% concentration and passed it thru Dowex XFS-4022, the ml at break
went from 390 to 450.
17
-------
Table 4. PHASE 3 - CONDITIONS OF DISPERSED DYES
Run #
resin type
1
strong base
2
strong acid
3
strong base
4
strong base
5
strong base
strong acid
6
strong acid
7
strong base
8
strong base
9
strong base
10
strong acid
11
strong acid
12
strong acid
Resin
# ml
IR-4B
IR-120
S-2
S-2
S-2
IR-120
IR-120
S-2
S-2
S-2
IR-120
IR-120
IR-120
17
17
30
17
8 of
each
tf-
17
17
17
17
17
17
17
pfl in
dye
9.1
9.0
9.0
8.3
8.3
8.3
9.4
9.0
9.1
9.0
9.1
9.2
pH out
dye
9.1
3.6
6.4
6.0
6.2
2.3
6.2
6.4
6.8
3.5
3.6
3.5
Drops/
5 sec
4
4
4
4
4
4
4
4
4
4
4
4
#Dyea
334
339
339
Mixb
Mixb
Mixb
334
515
541
339
515
541
aDye waste used at full strength,
°Mix is the four (4) dye numbered
if less, % stated.
wastes combined in equal amounts.
18
-------
Table 4 (continued). PHASE 3 - CONDITIONS OF DISPERSED DYES
Run #
resin type
13
weak base
14
weak acid
15
weak acid
16
weak acid
17
strong base
strong acid
18
same
19
same
20
same
21
same
21
continued
22
strong acid
strong base
23
same
24
same
25
same
Resin
# ml
A- 7
A- 7
A-7
A- 7
S-2 over
IR-120
Same
Same
Same
Same
Same
IR-120
over
S-2
Same
Same
Same
17
17
17
17
17
17
17
17
17
17
17
17
17
17
17
17
pH in
dye
9.1
9.2
9.1
9.4
9.4
9.0
9.1
9.1
8.3
8.3
8.3
9.1
9.0
9.0
pH out
dye
No data
No data
No data
No data
3.0
3.0
3.2
3.1
3.0
3.0
6.2
2.3
6.4
6.2
6.1
Drops/
5 sec
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
#Dyea
334
339
515
541
334
339
515
200
Mixb
Mixb
334
515
541
339
aDye waste used at full strength, if less, % stated.
"Mix is the four (4) dye numbered wastes combined in equal amounts.
19
-------
Table 4 (continued). PHASE 3 - CONDITIONS OF DISPERSED DYES
Run #
resin type
26
same
27
strong base
strong acid
28
strong acid
strong base
29
weak base
30
weak base
31
neutral
32
same
33
same
34
same
34
1st regener-
ation
34
2nd regener-
ation
34
3rd regener-
ation
35
weak acid
36
same
Resin
# ml
Same
S-l over
IR-120
IR-120 ove:
S-2
A- 7
A- 7
4022
Same
Same
Same
Same
Same
Same
IRC-50
Same
17
14
14
14
14
14
14
17
17
17
51
51
51
51
14
14
pH in
dye
9.0
8.5
4.7
8.5
8.5
8.5
9.0
8.5
8.3
9.0
9.0
9.0
9.0
8.0
8.0
pH out
dye
6.0
No data
2.3
6.0
4.5
6.5
6.5
9.0
8.5
8.3
9.0
9.0
9.0
9.0
4.0
4.0
Drops/
5 sec
4
2
2
2
2
1
1
1
1
1
3
3
3
3
1
1
#Dy_ea
Mixb
Mixb
Mxb
Mixb
50%
Mixb
75%
541
75%
Mixb
75%
Mixb
50%
541
Same
Same
Same
Mixb
75%
Mixb
50%
20
-------
Table 5. PHASE 3 - REMOVAL OF DISPERSED DYES
Run #
ml
at break
Remarks on color
Color
number3
8
10
11
12
50
100
100
200
400
400
400
400
400
400
225
100
Color not removed.
Faint pink then much
darker at break.
Faint blue then much
darker at break.
Faint tan then column
clogged.
Faint pink then
deeper-at break.
Faint gray then
deeper at break.
Faint pink then
deeper at break.
Same.
Same.
Faint blue then darker
at break.
Faint gray then 'darker
at break.
Faint pink then darker
at break.
1.039
1.66
aMost of readings not recorded up to run #27. Some anomalous readings
due to slight cloudiness.
21
-------
Table 5 (continued) . PHASE 3 - REMOVAL OF DISPERSED
Run #
ml
at break
Remarks on color
Color
number3
13
14
15
16
17
18
19
20
21
21
continued
22
23
24
25
200
200
200
200
200
200
150
150
150
150
Color not removed.
Same.
Same.
Same.
These two columns in tan-
dem gave best results to
date. Faint color from
start-
Same.
Same.
Same.
Same.
Regenerated 3 times. Column
still as good, same faint
pink color.
Acid resin over did not
remove color as well as
Run #17.
Same.
Same.
Same.
1.03
0.87
0.75
aMost of readings not recorded up to Run #27.
due to slight cloudiness.
22
Some anomalous readings
-------
Table 5 (continued). .PHASE 3 - REMOVAL OF DISPERSED,DYES
Run #
26
27
28
29
30
31
32
33
34
34
1st regener-
ation
34
2nd regener-
ation
34
3rd regener-
ation
35
36
ml
at break
150
195
195
125
125
100
100
320
390
450
735
700
650
600
100
100
Remarks on color
Same.
Almost clear pink.
Same color.
Not as efficient as
above .
Pink color.
Color came through
from start.
Same.
Eluate was clear,
then straw color.
Same.
Clear.
Clear and then slight
haze, yet no color.
Same.
Same.
Same.
Same
Same
Color
number3
0.112
0.106
2.000"1"
2.000+
1.000
0.061
0.006
1.01
1.2
1.2
1.3
1.4
1.2
23
-------
As discussed under "Mechanisms Of Dye Removal," the chemical equations
for the resins' reactions with the dye waste water are below.
In the case of Dowex XFS-4022, the phenomenon involves van der Waal's
forces which bind the dye to the solid resin which is a styrene-divinyl-
benzene copolymer. From a practical concept the hydrophobic or nonpolar
aromatic portions of the resin are attracted to the aromatic portions
of the dye.
-CH
u
CH3COHN
CIBOCET YELLOW 2GC
STYRENE DIVINYLBENZENE COPOLYMER
CH,
The benzene rings in both the resin and the dye attract each other.
The weak acid resin IRC-50 is a copolymer of methacrylic acid and divinyl-
benzene. Here not only do the van der Waal's forces work but also the
carboxylic acid group of the methacrylic acid copolymer reacts and bonds
with the alkyl amino groups in both Cibacet Blue BN and Terasil Scarlet.
Also the acid resin reacts with the soluble sodium salt of the Yellow
2GC, which becomes insoluble.
METHACRYLIC ACID-
DIVINYLBENZENE COPOLYMER
CIBOCET BLUE BN
24
-------
—CI
-CH-
-CHr
TERASIL-SCARLET B
The strong acid IR-120 is a styrene-divinylbenzene sulfonated copolymer.
The strong sulfonic acid groups bond to the basic amino groups as the
carboxylic acid groups did with the two above dyes. Also it reacts with
the sodium salt of Yellow 2GC and precipitates as below.
COPOLYMER OF STYRENE-DIVINYLBENZENE SULFONIC ACID
- —CH
- —CH
2 ^CH
NHCH2CH2 OCH2CH2OH
CIBOCET BLUE BN
CIBOCET YELLOW 2GC
25
-------
CH CH
+NH2CH3
NHCH2CH2OCH2CH2OH
Sulfonic acid of ion-exchange resin
forms strong salt bend with basic
amino group of Cibocet Blue BN.
Somewhat soluble salt of
Cibocet Yellow 2GC is
precipitated as insoluble
phenol compound.
The strong basic resins Permutit S-l and S-2 are styrene-divinyl benzene
copolymers with tetraalkyammonium chloride groups. These strong
anionic resins having alkylammonium chloride groups will react via
ion exchange of Cl~ for dye anions. One can see this when the dye
waste which is at a basic pH 8.5 flows down the quarternary ammonium
chloride column which is at an acid pH of 4 to 5. Thus, one first
observes an acid effluent but the basic pH of the waste keeps neutral-
izing the acid column until the pH goes up to the 8.5 pH original of
the waste. Also the benzene groups, as above, in both the resin and
the dye interact via Van der Waal's forces.
26
-------
PERMUTIT S-l: THE TETRAMETHYLAMMONIUM CHLORIDE COPOLYMER
CH
CH3COHN
SALT BONDED COMPOUND OF S-l WITH CIBOCET YELLOW 2GC
CH3COHN
(CH3)3
-CH2~
+(NaCl)
SODIUM CHLORIDE
27
-------
In run #34 the volume of dye removal after three successive regenera-
tions of Dowex-4022 went from 700 ml to 600 ml.
The volume of dye removal for the weak acid resin (IRC-50) is 100 ml,
run #35, as compared to 390 ml, run #32, for the neutral resin, Dowex-
4022.
We did not notice any physical degradation of the resins in these
experiments.
When the dyes and other additives, surfactants, etc. are regenerated
with methanol or toluene from neutral resins, they have the same
chemical structure as when they were applied.
Most of the structures of the dyes from Glen Raven and all of the resins
in the above discussion have been described except Duolite A-7. This
is a styrene copolymer with basic amine groups on it as follows:
DUOLITE A-7 STYRENE COPOLYMER
PHASE 4
The ultimate choice of resin and combination of resins is dependent
largely on operating costs. The ease of regeneration, maximum number
of allowable regenerations (still at same high volume amount of color
removal), and the maximum amount of influent before each regeneration
are the key cost factors. With these in mind, it was deemed a good
choice to use a neutral column as the main column, because the cost
and ease of regeneration is much less when you use a cheap neutral
organic solvent regenerant. The solvent is easily distilled and reused,
but this is not so with aqueous acid and base regenerants. The main
reason is that these dispersed dyes are readily soluble in organic
solvents such as methanol. They are not soluble (as the mixture of
the three chemical dye structures shown in this report) in aqueous
caustic solutions, and strong acid solutions only partially dissolve
them. Methanol was chosen for these dispersed dyes as the practical
regenerant of choice. Neutral solvents also regenerate neutral resins
much more efficiently than acid or basic resins. As discussed
previously, the neutral resins sorb these dispersed dyes by weak van
28
-------
der Waal's forces. These dyes are readily removed by the strong
solubility effect of the methanol for the dye. However, these same
disperse dyes are not soluble in aqueous acid or base solutions that
we use and hence do not remove the dyes from either an acid or basic
resin.
As seen from Table 6, we selected three sets of resin columns. In all
the sets the first column in tandem contained a neutral resin and the
second contained either Duolite A-7 (a weak base), Duolite S-30 (a
very weak acid), or Amberlite IRC-50 (a weak acid).
The results are shown in Figure 4. Over each test tube is a number
as follows: Number (1) the starting dye mix, (2) the effluent just
from the XAD-7 restn column, (3) the effluent from the tandem columns
of XAD-7 over Duolite A-7 (runs #40 to 46), (4) XAD-7 over IRC-50
(run #37) and (5) XAD-7 over S-30 (run #38). In Figure 5, the deeply
colored influent is shown going to the XAD-7 column and then to the
Duolite A-7 column where it emerges as a colorless effluent in the
receiving flask.
The most efficient combination was the neutral column, XAD-7 followed
in tandem with Duolite A-7. All the color was removed by this combi-
nation, a very faint colorless turbidity was left which naturally gave
some absorption reading on the Spectronic 20. For practical purposes
we had removed all the color and left nothing but a trace of opacity.
At the suggestion of Dr. Samuel Karickhoff, we investigated this trace
of remaining turbidity to see if it was any of the remaining dispersed
dyes which now might be colorless being at different pH values. We
carefully adjusted this slightly turbid solution in 0.5 pH increments
from a pH of 9.0 down to 3.0 and found no color at any pH increment.
It does not appear to be any of the original dyes. It may be some oil
that was original on the yarn or in the surfactant system.
PRETREATMENT OF RESINS
Thirty milliliters of XAD-7 was transferred to the column by slurry
method with distilled water. Then 60 ml water at a rate of 4 bed vol/hr.
was passed through. Then 30 ml of methyl alcohol at the same rate
followed by a slow water backwash for 10 minutes was added to expand
the bed 50%. The bed was then allowed to settle and was ready to accept
the influent dye wastes.
29
-------
Table 6. PHASE 4 - RESIN COLUMNS IN TANDEM WITH 100% OF MIXED DYES
Run #
37
38
39
40
41
42
43
44
45
46
Resins
XAD-7
over
IRC-50
XAD-7
over
S-30
4022
over
A-7
XAD-7
over
A-7
Same
Same
Same
Same
Same
Same
ml
resin
30
over
30
30
over
30
70
over
70
30
over
30
Same
Same
Same
Same
Same
Same
PH
effluent
5.1
6.2
5.1
5.0
6.8
7.2
8.0
8.5
5.0
6.5
ml
break
500
1000
500
1000
1000
1000
1000
1000
1000
1000
Color
no.
0.88
0.47
0.45
0.43
0.44
0.45
0.44
0.44
0.43
0.45
Remarks
Not very efficient and difficult to regen-
erate IRC-50 column.
Duolite S-30 has to be regenerated at the
same volume of 1000 ml as XAD-7.
The 4022 column has to be regenerated afte
every 500 ml. Only regenerated this pai
two times and stopped.
The best pair of columns by far.
The XAD-7 column had to be regenerated eac
time after 1000 ml of dye waste.
Its bottom column, Duolite A-7, did not
have to be regenerated until 5000 ml
came from the effluent of its XAD-7
column.
Regenerated Duolite A-7 at Run #46 even
though the Color no. is about 0.44.
All the color has been removed.
The faint remaining turbidity gave the
0.44 average reading, see photographs.
(jO
o
-------
Figure 4. Visual comparison of various best runs
of color removal for dispersed dyes.
31
-------
Figure 5. Colorless effluent emerging in flask from
XAI>-7 over Duolite A-7, runs #40 to 46.
32
-------
XFS-4022 is transferred dry to the column. Then washed with 2 bed
volumes of methanol at 4 bed volumes per hour (4BVH). Finally, it was
washed with 2 BV of water at 4BVH and was now ready for use.
Duolite A-7 and S-30 need no pretreatment. They are transferred to
column by a slurry of water and are ready to use.
IRC-50 was placed in 3 times its volume of water and stirred with a
magnetic stirrer for 3-4 hours and transferred to column for usage.
XAD-7, the most efficient resin, #40, Table 6, was regenerated six
times using the following technique at break-point: wash with 50 ml
of water at 0.5 ml/min, regenerate with 100 ml methanol at 0.5 ml/min
and wash with 50 ml of water. The 100 ml of methanol removed all the
dyes from the column. Duolite A-7 which is the 2nd column in tandem
had to be regenerated after only 5,000 ml of influent. It was regen-
erated at 0.5 ml/min with 200 ml of alcohol which removed all the dyes,
Then it was put back into its salt form with 60 ml of 1% HC1 at 2
ml/min.
33
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
.REPORT NO.
EPA-660/2-75-016
3. RECIPIENT'S ACCESSION-NO.
4.TITLE AND SUBTITLE
S. REPORT DATE
June 1975
Application of Exchange Resin for Treatment
of Textile Dye Wastes
6. PERFORMING ORGANIZATION CODE
7.AU
Allison Maggiolo
J. Henry Sayles
8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
Bennett College
Greensboro, North Carolina
10. PROGRAM ELEMENT NO.
1BB036
27420
11. CONTRACT/GRANT NO.
R802586
12.SPONSORING AGENCY NAME AND ADDRESS
US Environmental Protection Agency
National Environmental Research Center-Corvallis
Southeast Environmental Research Laboratory
College Station Road, Athens, Georgia 30601
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
IS. SUPPLEMENTARY NOTES
16. ABSTRACT
The objective of this study was to investigate the use of ionic and neutral
polymeric resins to remove and recover textile dye wastes before such wastes are fed
Into rivers and streams.
Initially, synthetic azo-dyes with various functional groups were used that
would represent a broad spectrum of textile dyes. Then, various types of actual plant
dyes waste, which included all the additives, were investigated. These dye wastes
consisted of direct, acid, basic, vat and dispersed dyes. They were screened against
various commerically available ionic and neutral resins to see which resin or resin
combination would remove them most efficiently. The data obtained in this investiga-
tion indicate that all except dispersed dyes could be removed to give a colorless
effluent. Therefore, considerable investigation was focuesed on dispersed dyes. The
complete color removal of dispersed dyes was accomplished with a neutral resin column
followed by a weak base column.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
[on Exchange, Cation Exchange, Textile
[ndustry, Wastewater Treatment, Water Reuse,
Dyeing, Tertiary Treatment
Textile Industry
05/03
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (ThisReport)
Unlimited
21. NO. OF PAGES
39
20. SECURITY CLASS (Thispage)
Unlimited
22. PRICE
EPA Form 2220-1 (9-73)
U.S. GOVERNMENT PRINTING OFFICE: 1975—698-714 /I67 REGION 10
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