WATER POLLUTION CONTROL RESEARCH SERIES 17010EAP10/70
FEASIBILITY OF LIQUID ION
EXCHANGE FOR EXTRACTING
PHOSHATE FROM WASTEWATER
ENVIRONMENTAL, PROTECTION AGENCY WATER QUALITY OFFICE
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
of pollution in our Nation's waters. They provide a
central source of information on the research, develop-
ment, and demonstration activities in the Environmental
Protection Agency, through inhouse research and grants
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Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports
System, Planning and Resources Office, Office of Research
and Development, Environmental Protection Agency, Room 1108,
Washington, D. C. 202-42.
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FEASIBILITY OF LIQUID ION EXCHANGE
FOR EXTRACTING PHOSPHATE FROM WASTEWATER
by
General Mills Chemicals, Incorporated
Minneapolis, Minnesota 55434
for the
ENVIRONMENTAL PROTECTION AGENCY
Program #17010 EAP
Contract #14-12-590
October, 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, B.C. 20402 - Price 50 cents
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EPA REVIEW NOTICE
This report has been reviewed by the
Environmental Protection Agency and
approved for publication. Approval
does not signify that the contents
necessarily reflect the views and
policies of the Environmantal Pro-
tection Agency, nor does mention of
trade names or commercial products
constitute endorsement or recommen-
dation for use.
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ABSTRACT
A variety of organic compounds were screened for utility in
extracting inorganic phosphate from water by the liquid ion
exchange process.
Organometallie compounds, metal salts of di-2-ethylhexyl
phosphoric acid and ferrocenium compounds were investigat-
ed. Only certain organometallies showed significant acti-
vity and this activity appeared to be concentrated in minor
constituents present in the samples. More specifically,
tribenzyltin compounds, possibly the hydroxide or its acid
salts, were active in selectively extracting phosphate in
the presence of chloride and sulfate.
This report was submitted in fulfillment of Program No.
17010 EAP, Contract No. 14-12-590, between the Federal
Water Quality Administration and General Mills Chemicals,
Incorporated.
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CONTENTS
Paqe
INTRODUCTION 1
SUMMARY AND CONCLUSIONS 7
EXPERIMENTAL 9
REFERENCES 27
ADDENDUM - AMMONIA EXTRACTION 29
APPENDIX 31
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FIGURES
Page
1. FLOW DIAGRAM OF LIQUID ION EXCHANGE PLANT 3
2. FRACTIONATE ON OF TRIBENZYLTIN ,HYDROXIDE 12
3. PHOSPHATE EXTRACTION ISOTHERM FOR TRI-
BENZYLTIN ACETATE 16
4. EXTRACTION OF PHOSPHATE BY TRIBENZYLTIN
ACETATE 17
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TABLES
Page
I. COMPOSITION OF AQUEOUS PHOSPHATE STOCK
SOLUTIONS 10
II. EXTRACTION OF PHOSPHATE WITH TRIBENZYL-
TIN HYDROXIDE 10
III. EXTRACTION OF PHOSPHATE WITH TRIBENZYL-
TIN ACETATE 14
IV. EXTRACTION OF PHOSPHATE WITH LABORATORY
PREPARED TRIBENZYLTIN ACETATE 15
V. EXTRACTION OF PHOSPHATE WITH TRIBENZYL-
TIN CARBONATE 18
VI. EXTRACTION OF PHOSPHATE WITH TRIBENZYL-
TIN BENZOATE 19
VII. EXTRACTION OF PHOSPHATE BY MISCELLANEOUS
ORGANOMETALLICS 21
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INTRODUCTION
THE REMOVAL OF PHOSPHATE FROM WATERS
Eutrophication of lakes by excessive algal growth has be-
come a serious problem and has prompted considerable re-
search on means for its prevention. One preventative
measure that has special merit is the removal of phosphorus
from municipal sewage plant effluents.
Secondary effluents from sewage plants contain substantial
concentrations of phosphorus and constitute a major source
of phosphorus nutrient for algal growth in natural waters.
Of the various essential algal nutrients, phosphorus ap-
pears to be the one which might be most amenable to con-
trol . Therefore, the removal of phosphorus from sewage
plant effluents could effect a phosphorus-starvation of the
algae. It is believed that blooms of blue-green algae can
be prevented by maintaining phosphorus levels of 0.01 mg/1
in lakes (1) .
Typical secondary effluents from municipal sewage plants
contain approximately 8 mg/1 phosphorus. Most of this
phosphorus is in the orthophosphate form (2). Assuming
that these effluents are diluted by a factor of 10 by the
receiving body of natural water, a suitable treatment of
effluent should reduce the phosphorus concentration to 0.1
mg/1. This would constitute a 99% phosphorus removal from
an effluent containing 8 mg/1 phosphorus.
A number of processes have been studied for removing phos-
phorus from sewage plant effluents. These include precipi-
tation with chemicals, ion exchange, biological treatment,
electro-chemical treatment, reverse osmosis, and electro-
dialysis. Precipitation and ion exchange appear to be most
practical to date. Treatment with chemical precipitants,
especially lime, is the most popular and most economical
process. Precipitation with lime followed by filtration
has been reported to effect approximately 95 percent phos-
phate removal at costs of at least 5 cents per 1000 gallons
of water treated (3). Solid ion exchange with resins also
has shown potential for removing phosphorus from sewage
plant effluents. However, since the resins are not selec-
tive for phosphate, other anions are removed and therefore
operating costs are estimated to be several times those
for lime treatment (3).
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Liquid ion exchange, a proven process for removing small
quantities of ions from water, however has not been inves-
tigated for phosphate extraction. This relatively new unit
process is used commercially for recovering uranium, vana-
dium, copper and other metals (4,5). Its feasibility for
removing alkylbenzene sulfonate detergent from sewage plant
effluents has been demonstrated (6). This system for ex-
tracting detergent also reduced substantially phosphate
concentrations. To date, however, there has been no con-
certed study on the potential" of liquid ion exchange for
phosphate extraction.
Liquid ion exchange processing has certain features that
make it attractive for the treatment of sewage plant efflu-
ent. It is a continuous hydraulic process, especially
amenable to the treatment-of large volumes of continuously
flowing water. It has flexibility to accomodate for
changes in the effluent and is readily automated. It is
capable of concentrating extracted species at least one
thousand-fold. Its economics are competitive with other
established commercial processes such as precipitation and
solid ion exchange. It is especially amenable to the in-
corporation of selectivity for one chemical species, e.g.,
phosphate.
The contamination of treated water with solvents might ap-
pear to be a deterent to the use of liquid ion exchange on
sewage plant effluent. In commercial metal extraction by
liquid ibn exchange, approximately 150 mg/1 of solvent are.
entrained in the treated water. But in these cases, con-
tamination of the water is no problem and economics are
satisfactory, therefore no effort is made to prevent this
entrainment loss of solvent. With proper engineering of
the process and.proper choice of liquid ion exchange re-
agent, this contamination of the treated water probably
could be reduced to the 1 mg/1 level.
LIQUID ION EXCHANGE - PRINCIPLE
Liquid ion exchange is a relatively simple unit process for
extracting ions from water. Figure 1, a flow diagram of a
conventional liquid ion exchange plant, illustrates the
principle involved.
In this diagram, water containing A the ion to be extract-
ed flows into a mixer. Here it is contacted with the liq-
uid ion exchanger, a solution containing several percent
liquid ion exchange reagent in a high boiling hydrocarbon.
The reagent is a water insoluble organic compound having
functionalities that have an affinity for A . During this
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LIQUID ION EXCHANGER
IN
ATER
and -*
r-IN
MIXER
SETTLER
LIQUID ION
EXCHANGER and A-
i r
MIXER
SETTLER
OUT '
I
U)
I
WATER
OUT
EXTRACTION
STAGE
AQUEOUS STRIPPER and A~
T
BLEED STREAM
to REMOVE A~
STRIPPING
STAGE
Figure I. Flow Diagram of Liquid Ion Exchange Plant
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contact, A is extracted from the water into the liquid ion
exchanger. The mixed liquids then flow into a settler.
From here the treated water flows_out the bottom and the
liquid ion exchanger containing A~ flows out the top to the
stripping stage.
In the stripping stage, A is stripped from the liquid ion
exchanger by contact with an aqueous solution of a strip-
ping reagent such as sodium hydroxide. The regenerated
liquid ion exchanger from the settler is recycled back to
the extraction stage to pick up more A~. "The aqueous
stripping solution also is recycled for reuse with a por-
tion bled off for continuous removal of A by precipita-
tion or other means.
The liquid ion exchanger components have extremely low
water solubility. The solvent is a hydrocarbon such as
a high boiling kerosene. The liquid ion exchange reagent,
is a high molecular organic compound having functionali- '
ties that combine selectively with A"~.
EXTRACTION OF PHOSPHATE BY LIQUID ION EXCHANGE
A literature survey (see Appendix) indicated that organic I
compounds containing metals would be good liquid ion ex-
change reagent candidates for selective phosphate extrac-
tion.
Organometallic compounds of the Group VA elements, e.g.,
As, Sb, Bi, and of Group IV A, e.g., Ge, Sn, Pb are report-
ed as having affinity for phosphate. Also, Bock and Bur-
hardt (7) and Schweitzer and McCarty (8) demonstrated that
weak organometallic bases extract inorganic anions from
water. Therefore, it appeared that weak organometallic
bases of metals, e.g., organotin, organoantimony, etc.
bases, should be investigated for phosphate extraction.
Another fruitful area for phosphate extraction appeared to
be with metal salts of organic acids. Gerige and Slamon (9)
found that strong acid ion exchange resins loaded with tri-
valent metal ions reacted with phosphate. Thus, the metal
salts of di-2-ethylhexyl phosphoric acids seemed to be
likely candidates for complexing with phosphate. The tri-
valent salts of aluminum, iron and chromium appeared to be
especially attractive. The desirable structures were
M(OH) 9^2^(OR)2 where M is the trivalent metal ion and R is
the 2-ethylhexyl group. It was anticipated that the OH
ions would exchange for phosphate.
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Ferrocenium compounds also were expected to have affinity
for phosphate. For example, the following reaction was
postulated.
Fe+ Cl~ + H2P04~ ^ Fe+ H2P04~ + Cl"
Ferrocenium Chloride
The ferrocenium compound would have to be alkylated to pro-
vide the solubility in organic solvents that is needed by a
liquid ion exchange reagent. The phosphate-loaded ferro-
cenium compound probably could be stripped of phosphate
with a reducing agent such as sodium borohydride or sodium
peroxide. This reduction, of course, would convert the
ferrocenium compound to the ferrocene which would have to
be reoxidized to the ferrocenium before reuse.
Generally, the experimental part of this study involved
screening the above mentioned metal-containing organic com-
pounds as liquid ion exchange reagents for selective phos-
phate extraction. Representative compounds were prepared
and dissolved in an organic solvent. These organic solu-
tions then were shaken with aqueous phosphate solutions
containing chloride, sulfate and bicarbonate. The result-
ing aqueous solutions were analyzed to determine the ex-
tent of phosphate extraction and the selectivity of ex-
traction.
AMMONIA EXTRACTION
The scope of contract No. 14-12-590 was changed at the re-
quest of the FWPCA after approximately eight months of in-
vestigation on phosphate extraction. The new direction
was to investigate the feasibility of liquid ion exchange
for extracting ammonia from water. About one month of ef-
fort was expended on the ammonia extraction study before
the contract was terminated. See the addendum for more
details.
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SUMMARY AND CONCLUSIONS
Various metal-containing organic compounds were screened
for activity as liquid ion exchange reagents for phosphate.
The compounds were tested for selectivity in extracting in-
organic phosphate from water into organic solvents in the
presence of chloride, sulfate and bicarbonate.
A commercial tribenzyltin hydroxide contained a component
which selectively extracted phosphate. The component was
identified as containing tribenzyltin carbonate and a tri-
benzyltin carboxylic acid salt. A concentrate of this com-
ponent extracted 52 percent of the phosphate from an aque-
ous solution containing 25 mg/1 phosphate, 166 mg/1 chlor-
ide and 212 mg/1 sulfate at pH 4.1. No chloride or sulfate
was extracted. An attempt to prepare a'concentrate of the
tribenzyltin carbonate was unsuccessful.
A commercial tribenzyltin acetate also selectively extract-
ed phosphate in the presence of chloride and sulfate. The
extraction was not as complete as with the tribenzyltin hy-
droxide component above and was not selective over bicarbo-
nate. The phosphate extracting activity in this case also
appeared to be due to a minor component.
Tribenzyltin benzoate, triphenyltin hydroxide, tri-n~butyl-
tin hydroxide, triphenylantimony hydroxide, triphenyllead
hydroxide and triphenylarsenic hydroxide did not show sig-
nificant promise for use in extracting phosphate from
water.
The trivalent iron, aluminum and chromium salts of di-2-
ethylhexyl phosphoric acid did not exhibit any significant
activity for extracting phosphate.
Alkylated ferrocenium compounds were prepared, but were too
unstable for testing their phosphate extraction activity.
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EXPERIMENTAL
EXTRACTION OF PHOSPHATES BY ORGANQMSTALL1CS
As mentioned earlier, our literature survey indicated weak
organometallic bases will extract phosphates. Probable
mechanism of extraction was as follows:
R3MA + H2P04 s ^ R3MH2P04 + A
Organometallic hydroxide compounds are good candidates for
extracting phosphate. They are preferred over other organ-
ometallic anion compounds since the exchanging hydroxyl
anion is not usually considered a pollutant of water.
The following organometallic compounds were tested for ex-
traction of phosphate: tribenzyltin hydroxide, triphenyl-
tin hydroxide, tri-n-butyltin hydroxide, triphenylantimony.
hydroxide, triphenyllead hydroxide and triphenylarsenic hy-
droxide .
Tribenzyltin Hydroxide
The extraction of phosphate by tribenzyltin hydroxide
({cyHTJ 3SnOH) was studied at pH 8.3, 7.0 and 4.1. Utiliza-
tion of this wide pH range enables one to identify compounds
which are selective for phosphate both at low and at high
pH's. If a compound was found to be selective for phos-
phate at pH 4, modification of the organic structure could
raise the effective extraction pH to perhaps 7 or 8. The
latter pH1s are more realistic in waste water systems. The
compositions of the aqueous phosphate stock solutions used
in the extraction studies are shown in Table I.
Extraction studies were performed as follows: an organic
solution of the organometallic compound was prepared in
toluene so that 5 ml contained two times as many equival-
ents of organometallic as H^PO* equivalents in 100 ml of
the aqueous stock solution. Five ml of a 4.3 g/1 solution
of tribenzyltin hydroxide (Alpha Inorganics lot no. 12268)
and 100 ml of aqueous stock solution were shaken together
for 2 minutes in a separatory funnel. The phases were al-
lowed to separate. The aqueous layer was drawn off, filter-
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ed and analyzed. The above procedure was repeated using 25
ml of tribenzyltin hydroxide solution. A summary of the
extraction data is shown in Table II.
TABLE I. COMPOSITION OF AQUEOUS PHOSPHATE STOCK SOLUTIONS*
Analytical Proced-
Solution ABC ure References
PH
PO ~
4
S04=
Cl"
HCO-,"
8.3
24.1
213
158
336
7.0
23.6
254
142
286
4.1
24.8
212
166
_ _
Standard Method**
ASTM D516
Standard Method**
ASTM D513
*
All concentrations are in mg/1
**
"Standard Methods for the Examination of Water and
Wastewater", llth ed.
TABLE II. EXTRACTION OF PHOSPHATE WITH TRIBENZYLTIN HYDROXIDE
Volume %
Ratio, pH pH [phosphate] phosphate) Phosphate
Expt org/aq initial final i'. / mg/1 f., mg/1 Extracted
1
2
3
4
5
6
5/100
25/100
5/100
25/100
5/100
25/100
8
8
7
7
4
4
.30'
.30
,00
.00
.10
.10
8
8
7
8
6
6
.48
.50
.82
.00
.27
.90
24
24
23
23
24
24
.1
.1
.6
.6
.8
.8
24
23
24
24
22
17
.3
.8
.3
.8
.4
.3
0
0
0
0
9
30
.7
.3
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Further analyses of the raffinate from the experiment at pH
4.1 (5 & 6) indicate no extraction of sulfate or chloride.
Thus, at pH 4.1 the tribenzyltin hydroxide selectively ex-
tracted phosphate in presence of chloride and sulfate.
Tribenzyltin hydroxide (Lot #12268) from Alpha Inorganics
was examined by infrared spectroscopy. The infrared spec-
tra wa^ quite weak in OH absorption. Thus, it was ques-
tionable as to how much of the sample was really tribenzyl-
tin hydroxide. Furthermore, the melting point of the sam-
ple was 110-120° C, whereas literature reports 117-121° C
(10) .
The tribenzyltin hydroxide (Lot #12268) was crystallized
from toluene to determine if the phosphate activity could
be concentrated. One crystallization gave 57% by weight
clear triclinic type crystals (Fraction A). These crystals
when dissolved in toluene did not extract any phosphate
from the pH 4.1 phosphate solution. Both extraction exper-
iments were carried out using the same weight concentration
of organic in toluene.
The mother liquor solids (Fraction B) were further purified
by extraction with hot methanol. The methanol insoluble
portion, (Fraction D) extracted 52% phosphate from pH 4.1
phosphate solution. The methanol soluble portion, (Frac-
tion C) extracted 42% phosphate. A summary of the above
data i^ given in Figure 2.
All of the fractions from the fractionation of tribenzyltin
hydroxide were examined by infrared spectroscopy. The in-
frared spectrum of tribenzyltin hydroxide (Lot no. 12268),
as previously mentioned, had a weak absorption in the OH
region of 2.75-3.On and a moderate absorption at 7.4 and
9.05|a. One possible assignment for the 7.4|a band is a car-
bonate. Lohmann (11) reports a very strong band at 7.4p. for
triethyltin carbonate. He also mentions that triethyltin
oxide and hydroxide absorbs carbon dioxide from the air
readily to form the carbonate.
Fraction A had an infrared spectrum different from that of
tribenzyltin hydroxide (Lot #12268). The total OH absorp-
tion and the absorption at 9.05n of fraction A were slight-
ly stronger and the 7.4(a band was missing in fraction A.
The infrared spectrum of fraction B differed from fraction
A by having a rather strong 7.4n band and no absorption at
9.In. No assignment could be made for the 9.1(a band. Frac-
tion B also had a weak 5.86n band (not present in A) which
is probably due to benzaldehyde.
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FIGURE 2. FRACTIONATION OF TRIBENZYLTIN HYDROXIDE
Tribenzyltin Hydroxide (Lot.#12268)
5 g, M.P. 110-120° C, 27.5% Sn,
30% Phosphate Extraction
Crystallized
from
Toluene
. -I: . - . -
Fraction A: (Crystals)
2.9 g, M.P. 110-120° C
0% Phosphate Extraction
Fraction D
(Methanol In-
',' solubles)
Amorphous Solid, __1.6 g,
32.2% Sn, 52% Phosphate
Extraction
Fraction B
1
(From Mother
Liquor)
Semi-Solid 2.1 g, 42%
Phosphate Extraction
Extracted with
Hot Methanol
Fraction C (Methanol Sol-
ubles)
White Solid, 0.5 g, M.P.
90-105° C 20% Sn, 42%
Phosphate Extraction
Fraction "C had more OH absorption than any of the other
fractions. Fraction C also had the 7.4|a band, which is be-
lieved due to carbonate. It also had a trace of benzalde-
hyde. Upon rerunning the spectra of fraction C five weeks,
later significant changes had occurred. Bands at 6.5(j and
7.05n were present that were not present before. It is
very likely that an ionized carboxyl group is responsible
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for the new bands.
The infrared spectrum of fraction D has only moderate dif-
ferences from the spectrum of fractions B & C. The 9.5^
and 7.4|a bands were about 50% stronger in fraction D than
in either C or B.
Fraction D was separable into four spots by thin layer
chromotography (TLC). The TLC plates were solvent develop-
ed with a 3:1 mixture of toluene and methanol. The spots
were observed with ultraviolet light and color/.was develop-
ed with concentrated sulfuric acid spray. The Rf values
were 0, 0.45, 0.60, 0.70. Additional experiments .showed
that the phosphate-active component was at R^ = 0 (original
spot) .
A toluene solution of D was shaken with aqueous phosphate
to form organic-phosphate complex in the toluene phase.
The resulting toluene solution loaded with,phosphate was
subjected to TLC.
Again four spots resulted (ultraviolet light identifica-
tion) at the same Rf values as the solution of D alone.
Only the spot at the origin, Rf = 0, showed phosphate acti-
vity on spraying with ammonium molybdate solution.
A preparative TLC was done on fraction D. The orgin spot
was collected and analyzed by infrared spectroscopy. The
infrared spectra was rather confusing. Part of the sample
was benzaldehyde; part gave appreciable alphatic CH2 ab-
sorption and there was a component which showed strong OH
absorption. However, the OH absorption was stronger than
anticipated for tribenzyltin hydroxide.
The above data indicated that the tribenzyltin hydroxide
(Lot #12268) was of questionable composition. To clarify
this point, an attempt was made to prepare some tribenzyl-
tin hydroxide by contacting the corresponding chloride with
sodium hydroxide. The procedure was as follows: 5 g of
recrystallized tribenzyltin chloride (M.P. 135-142° C),
Alpha Inorganics, was dissolved in 250 ml of toluene and
contacted three times with 150 ml of aqueous 0.5M sodium
hydroxide. The aqueous raffinate from the final contact
gave a negative silver nitrate test for chloride. The tol-
uene solution then was washed with distilled water until
neutral, filtered through paper and placed in a refrigera-
tor. After standing overnight, the solution was filtered
yielding 3.5 g of clear square cyrstals (M.P. 119-124°).
These crystals were similar in appearance to the crystals
of fraction A in the "tribenzyltin hydroxide" separation
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scheme. The crystals were redissolved in toluene and con-
tacted with pH 4.1 phosphate solution. No extraction of
phosphate was observed. The infrared: spectrum of the crys-
tals showed a very weak OH band and a strong 9.In band.
The carbonate band, 7.4u, -was absent. The above data indi-
cate we were unsuccessful in preparing the hydroxide. In
fact, we probably made the oxide.
A similar experiment was run without attempting to isolate
the tribenzyltin hydroxide, thus perhaps avoiding conver-
sion to the oxide. The resultant toluene solution extract-
ed 9.7% phosphate from a pH 4.1 solution. Although this is
an increase in phosphate activity, it does not compare'to
the 30% phosphate activity with our original "tribenzyltin
hydroxide" sample.
Tribenzyltin Acetate
The studies in "tribenzyltin hydroxide" indicated that
there is some component other than the hydroxide which is
doing the phosphate extraction. One possibility was tri-
benzyltin acetate. Therefore, a 4.74 g/1 solution of tri-
benzyltin acetate (from Alpha Inorganics) in toluene was
shaken in a separatory funnel for 2 minutes with aqueous
phosphate solutions at pH 4.1, 7.0, and 8.3. The results
are given in Table III.
TABLE III. EXTRACTION OF PHOSPHATE WITH TRIBENZYLTIN ACETATE
Volume ^-. ,- i %
Ratio pH pH [phosphatej iPhosphatej Phosphate
Org/Aq initial final i., mg/1 f., mg/1 Extracted
25/100 8.30 _ 7.41 24.1 15.7 34.9
25/100 7.00 7.23 23.6 16.3 31.0
25/100 4.10 4.68 24.2 14.6 39.7
There was no extraction of chloride or sulfate by the tri-
benzyltin acetate. The experiment at pH 8.3 was repeated
in order to check the validity of the phosphate results and
also to check for bicarbonate extraction. (In the previous
experiment, there was not enough sample to check for HCO3
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extraction.) Results of the repeat experiment were: 41.7%
extraction of phosphate and 44.8% extraction of bicarbonate
(from 262 mg/1 to 146 mg/1 HC03~).
Extraction isotherm data were obtained on this commercial
sample of tribenzyltin acetate to help clarify its activity,
Separatory funnel extraction experiments were done as be-
fore, but only at pH 4. The resulting isotherm is shown in
Figure 3. \The shape of the isotherm indicated excellent
extraction characteristics. Figure 4 is the isotherm data
replotted and shows that the phosphate could be completely
extracted if there are large amounts of active extractant
present. Assuming that tribenzyltin acetate is the extrac-
tant, the isotherm data indicates only 4% of theoretical
loading of phosphate is being achieved.
Infrared data indicate the sample is approximately 75% ace-
tate. The shape of the isotherm, however, implies that an
impurity rather than the acetate is actually -doing the ex-
traction. Additional work would be necessary to prove this
conclusion. The above data on commercial tribenzyltin ace-
tate indicates again, like with tribenzyltin hydroxide,
that an impurity is responsible for the phosphate extrac-
tion. Therefore, some tribenzyltin acetate was prepared.
The procedure was as follows: a sample of tribenzyltin
chloride from K & K laboratories, M.P. 136-142° C (litera-
ture reports 142-144°), in toluene was shaken with 10%
aqueous sodium acetate two times. The final aqueous raffi-
nate gave a negative silver nitrate test for chloride.
Based on chloride analysis, 94% conversion was achieved.
After washing and filtering through paper, the toluene sol-
ution of tribenzyltin acetate was contacted with phosphate
solutions at pH 8.0, 7.0, and 4.1 in the usual manner.
Table IV gives the results of the phosphate extraction.
TABLE IV. EXTRACTION OF PHOSPHATE WITH LABORATORY
PREPARED TRIBENZYLTIN ACETATE
Volume j _ _ , I %
Ratio pH pH [phosphate] [Phosphate] Phosphate
Org/Ag initial final i , mg/T ^E . , mg/1 Extraction
25/100 8.05 7.32 23.0 21.4 10.8
25/100 7.00 7.18 23.6 20.4 13.5
25/100 4.10 5.20 24.2 19.1 21.1
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i i
( Aqueous initially
25 ppm. phosphate )
I I
2 4 6 8 10 12
[PHOSPHATE] AQUEOUS , ppm
14 16
Figure 3. Phosphate Extraction Isotherm for Tri benzyl tin Acetate
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o
UJ
o
<
tr
x
UJ
UJ
I
Q.
O
X
Q.
100
90
70
50
30
10
1.0
1
I
2.0 3.0
AQUEOUS : ORGANIC RATIO
4.0
5.0
Figure 4. Extraction of Phosphate by Tribenzyltin Acetate
-------
The data in Tables III and IV indicate the laboratory pre-
pared tribenzyltin acetate has only about one half the
phosphate extraction activity of the coiranercial sample.
The lower phosphate activity again indicates that some-
thing in addition to the tribenzyltin acetate is extracting
phosphate.
Tribenzyltin Carbonate
Another possible impurity in tribenzyltin hydroxide that
might be the active ingredient is tribenzyltin carbonate.
Tribenzyltin carbonate was prepared as follows: an 8.98
g/1 solution of tribenzyltin chloride in toluene was shaken
with an equal volume of 5% aqueous sodium carbonate three
times. Final aqueous raffinate gave a negative silver ni-
trate test for chloride. The toluene solution was washed
with distilled waiter until neutral. The resultant toluene
solution was tested for phosphate extraction at pH 4.1 and
8.0 in the usual manner. Results are given in Table V.
TABLE V. EXTRACTION OF PHOSPHATE WITH
TRIBENZYLTIN CARBONATE
Volume
Ratio
Orq/A q
25/100
25/100 '
pH pH
initial final
8.05
4.10
8.20
6.72
[Phosphate]
i., mq/1
23.0
24.2
i 1
[Phosphate]
f., rng/I
23.4
22.7
o/
/a
Phosphate
Extracted
0
6
The above phosphate extraction results are lower than expec-
ted. A portion of the toluene solution of tribenzyltin
carbonate before extraction was evaporated to dryness in
order to obtain a sample for infrared analysis. The infra-
red spectrum of the residue indicated no carbonate forma-
tion and looked like that of the starting material, tri-
benzyltin' chloride. The original tribenzyltin carbonate
sample showed a small amount (5-10%) of absorption at 7.4|a,
which could be due to carbonate.
The residue sample which was analyzed by infrared, was re-
dissolved in toluene and shaken with pH 4.1 phosphate solu-
tion. This time 22% phosphate was extracted as compared to
-18-
-------
6% before evaporation and redissolving in toluene. The
above data is somewhat confusing. Perhaps there was very
little, if any, conversion to the carbonate while the sam-
ple was in solution. Upon removal of solvent there may have
been more of the chloride converted to the carbonate by re-
action with carbon dioxide in the air. Thus, the 5-10% of
carbonate indicated by infrared may be responsible for the
22% extraction of phosphate. A pure sample of tribenzyltin
carbonate would be needed to prove this theory.
Tributyltin Benzoate
Throughout the infrared examinations of "tribenzyltin hy-
droxide" fractions, ionized carboxyl and small amounts of
benzaldehyde were evident. This leads to the belief that
perhaps an organotin benzoate might be a phosphate extrac-
tant. A sample of tributyltin benzoate was obtained from
Alpha Inorganics and tested for phosphate extraction at pH
8.0, 7.0, and 4.1. Results are given in'Table VI.
TABLE VI. EXTRACTION OF PHOSPHATE WITH TRIBUTYLTIN BENZOATE
Volume , %
Ratio pH pH Phosphate Phosphate Phosphate
Org/Aq, initial final i., mg/1 f., mg/1 - Extracted
25/100 8>05 7.81 23.0. 23.0 0
25/100 7.00 7.80 23.6 23.4 0
25/100 4.10 5.20 24.2 23.0 5.0
The results of Table VI indicate tributyltin benzoate pro-
bably is not our unknown phosphate extractant.
SUMMARY OF RESULTS WITH ORGANOTIN COMPOUNDS
A fraction from a commercial sample of tribenzyltin hydrox-
ide selectively extracted 52% phosphate at pH 4.1 in the
presence of chloride and sulfate. Although positive iden-
tification was never achieved the active ingredient might
be tribenzyltin hydroxide, carbonate or a tribenzyltin car-
boxylic acid salt. A commercial sample of tribenzyltin
-19-
-------
acetate was found to extract phosphate over a pH range of
4.1 to 8.0. Maximum extraction of 40% was achieved at pH
4.1. Extraction was selective over chloride and sulfate but
not bicarbonate. Forty-five percent of bicarbonate was ex-
tracted. However in this case also, it appears that the ex-
traction activity is due to a minor constituent.
The data are insufficient to tell if tribenzlytin carbonate
extracts phosphate. A preparation containing 5-10% of tri-
benzyltin carbonate extracted 22% phosphate at pH 4.1. Tri-
butyltin benzoate is ineffective for extracting phosphate.
MISCELLANEOUS ORGANOMETALLICS
A variety of organometallies were screened for extracting
phosphate. The screening process was the same as with "tri-
benzyltin" compounds, i.e., contacting an organic solution
of the organometallic with aqueous phosphate solutions at
pH 8.3, 7.0, and 4.1. The compounds tested were triphenyl-
tin hydroxide, tri-n-butyltin hydroxide, triphenylantimony
hydroxide, triphenyllead hydroxide and triphenylarsenic hy-
droxide. Except for triphenyltin hydroxide, all of the
above compounds were received as the chloride and were con-
verted to the hydroxide by contact with aqueous sodium hy-
droxide. A summary of the results of these organometallies
is given in Table VII.
The results of the triphenylantimony hydroxide and the tri-
phenylarsenic hydroxide must be viewed with caution since
precipitates formed during phosphate analyses. Arsenic is
known to interfere with the phosphate analysis. In order
to determine if the triphenylarsenic hydroxide contains an-
alytical interferences, a 4.03 g/1 toluene solution of tri-
phenylarsenic hydroxide was contacted with an equal volume
of 0.1 M bisulfate solution. The aqueous bisulfate raffi-
nate solution was combined with an equal volume of 23.4
mg/1, pH 4.1 phosphate solution and analyzed for phosphate.
The resultant analysis gave a value of 8.0 mg/1 phosphate.
Theoretically, 11.7 mg/1 should have been obtained. Thus,
the value was 32% low.
A similar test for analytical interferences was done with
the triphenylantimony hydroxide. The test was: to an ex-
traction raffinate, which analyzed 17.3 mg/1 phosphate, was
added an equal volume of 50 mg/1 phosphate solution. The
resultant solution analyzed 31.4 mg/1 (theory is 33.6 mg/1)
or 6.5% low. Thus, the results with triphenylantimony hy-
droxide may be fairly valid. However, caution should still
be used when interpreting the triphenylantimony hydroxide
-20-
-------
TABLE VII. EXTRACTION OF PHOSPHATE BY
MISCELLANEOUS ORGANOMETALLICS
Phos- Phos- Phos- Cone
Com- Org/ pH pH phate phate phate Organic Org,
pound Ag initial final _i_, mq/1 f, mg/1 Extrd Solvent mg/1
Triphenyltin hydroxide
1/2
1/2
1/2
8.
7.
4.
Tri-n-butyltin
1/4
1/4
. 1/4
8.
7.
4.
31
00
10
8
7
6
.58
.99
.49
24
23
24
.1
.6
.8
23
24
24
.4
.2
.2
2.9
0
0
Toluene 3860
hydroxide
31
00
10
8
8
7
.69
.09
.42
24
23
24
.1
.6
.8
23
24
22
.8
.5 '
.4
0
0
9.7
Toluene 3240
Triphenyl antimony hydroxide
1/4
1/4
8.
7.
1/4 4.
1/4 4.
Triphenyl lead
1/4
1/4
1/4
8.
7.
4.
31
00
8
8
.65
.20
10 7.00
10 7.08
hydroxide
31
00
10
Tr iphenylar sen ic
9
9
9
.40
.29
.31
24
23
24
24
24
23
24
.1
.6
.8
.8
.1
.6
.8
16
15
12
17
23
23
23
.3*
.7*
.3*
.3*
.0
.0
.4
32.7
33.4
50.6
30.3
4
2.6
6.0
Benzene 4070
Chloro- 4840
form
hydroxide
1/4 8.31 8.68 24.1
1/4 7.00 8.30 23.6
1/4 4.10 5.23 24.8
15.7* 34.8
15.9* 32.7
15.4* 38
Toluene 4030
Precipitates formed during analysis for phosphate.
data. In view of the possible toxicity problems with anti-
mony compounds we decided to concentrate our research on
organotin compounds rather than antimony compounds.
-21-
-------
EXTRACTION OF PHOSPHATE BY METAL SALTS OF DI-2-ETHYLHEXYL-
PHOSPHORIC ACID (D2EHPA)
A literature survey (see Appendix) has revealed a wide var-
iety of compounds, clays, humates, lipids, and proteins
which appear to bind metal ions such as Cr+3, Al+3 and Fe+3.
The above technique may be useful for selectively extract-
ing phosphate. Al+3, Fe+3 and Cr+3 metal salts of Di-2-
ethylhexylphosphoric acid (D2EHPA) were chosen as possibil-
ities for phosphate extraction. The equivalency ratios of
metal to D2EHPA were varied in order to obtain the desired
metal salt, namely M(OH)2^2^(OR)2' w^ere M is the metal ion,
e.g., Fe+3 and R is CH2CH(C2H5)CH2CH2CH2CH3. It was theor-
ized that the hydroxyl group of this chemical species would
exchange for H2PO. or HP04.
Iron, Aluminum and Chromium Salts of D2EHPA
The general experimental procedure for preparing the iron
sal;t of D2EHPA was as follows: A 0.01065N toluene solution
of D2EHPA, aqueous FeCl3-3H20 and aqueous NaOH were shaken
together in a separatory funnel for 2 minutes. The aqueous
layer was drawn off and the pH was determined. The toluene
phase was washed with distilled water until neutral.
The resultant toluene solution of iron salt of D2EHPA was
contacted with phosphate solutions at pH 4.0, 7.0 and 8.3
in the same way as described earlier. The equivalency
ratio of D2EHPA to Fe+3 (and the raffinate pH) were varied
from 2:1 - 1:1.33 in order to give different complexing
conditions. The resulting data indicated that very little,
if any, phosphate was extracted by the iron salt of D2EHPA.
The formation of fine precipitates complicated analyses in
this portion of the study.
Aluminum and chromium salts of D2EHPA were prepared and
tested in a manner similar to that used for the iron salt.
Neither of these showed any significant activity in extrac-
ting phosphate.
FERROCENIUM COMPOUNDS
It was postulated that ferrocenium compounds would extract
phosphate. The extraction would be achieved by exchanging
the anion of the ferrocenium compound for H2PO.~, e.g.,
-22-
-------
\ o / FeA . + H2P04 > f oj
FeHPO + A
where A is an anion such as chloride or sulfate.
In order to achieve solubility in organic solvents it was
necessary to prepare an alkylated ferrocenium compound.
With the proper alkylated ferrocenium compound the normal
liquid ion exchange process could be used.
The procedure of Vogel (12) was used for preparing the in-
termediate alkylated ferrocenes. The synthesis involves
the Friedel-Crafts acylation with an acid chloride in pre-
sence of A1C1-. followed by a Clemensen reduction of the
acyl derivative.
X\ A1C13. >/\
Co^ Fe + 2RCOC1 ^ r o^
-C-R
(ferrocene) Fe
-C-R \ ° / ~CH2~R
HCl',Zn \
HgCl2
-C-R / o \-CH2R
(alkylated ferrocene)
The alkylated ferrocene on oxidation would give the desired
alkylated ferrocenium compound.
-23-
-------
(ox)
o \ -CH2~R / o \ -CH0-R
(alkylated ferrocen-
ium compound)
The first choice for an alkylated ferrocene was 1,1'-di
(2-ethylhexyl) ferrocene. Synthesis of this latter com-
pound was unsuccessful due to an unexpected side reaction
occurring during the Friedl-Crafts acylation. The side re
action was as follows:
CH->-(CH:,)..-CHCCl + A1C1-
o
2-methyl-5 ethyl cyclopentanone
This side reaction has been reported (13). The next choice
was to synthesize 1,1'-didecylferrocene, which was prepared
successfully.
The literature (14,15,16) reports ferrocene to be easily
oxidized ariodically or by a variety of chemical oxidants to
the stable, blue ferrocenium cation Fe(C5H5)2 . Electro-
lytic oxidation of 1,1'-didecylferrocene was achieved in a
HC104~95% ethanol solution. However, attempts to isolate
the "ferrocenium" cation in toluene were unsuccessful.
The experiment procedure was as follows: A solution of O.lg
1,11-didecylferrocene and 1 g of 70% HCl04 in 100 ml of 95%
ethanol was placed in an electrolytic cell. The electro-
lytic cell consisted of a 250 ml beaker, a magnetic stirrer,
a platinum gauze anode and a copper cathode. A potential
of 4.1 volts'was applied to the cell. The solution gradual-
ly changed from a yellow to a green to a blue-green color.
When the blue-green color was achieved, the passage of cur-
rent was stopped. (Further application of current results
in a yellow solution, which according to infrared spectro-
scopy is a mixture of hydroxyl and carbonyl compounds.)
Attempts to extract the blue "ferrocenium" cation from the
-24-
-------
95% ethanol into toluene resulted in a yellow toluene solu-
tion. Infrared analysis of the yellow toluene solution in-
dicates no "ferrocenium" ion and only evidence of both hy-
droxyl and carbonyl absorption. This data indicates the
alkylated ferrocenium compound underwent further oxidation
to oxygen-containing structures.
Chemical oxidation by CrOo was successful in achieving the
blue ferrocenium ion. However, the blue alkylferrocenium
ion was stable only for a short time. Oxidation was achiev-
ed as follows: A 7.5 ml of a 2%, wt/vol, solution of 1,1'-
didecylferrocene in Skellysolve B was shaken for 15 minutes
with 37.5 ml of a solution containing 0.284 g Cr,O3-50 g
HC104 per liter. The aqueous phase was drawn off and the
resultant blue organic phase was dried over Na^SO^. An in-
frared spectrum was run on the blue organic solution imme-
diately. The infrared spectrum indicated ferrocenium ion
to be present as evidenced by an absorption at 12.65|u (17).
The blue organic solution of ferrocenium ion gradually
turned yellow over a period of a few hours. 'Thus, it ap-
pears that alkyIferrocenium ions are not as stable as fer-
rocenium ions.
Thus in summary, synthesis of 1,I1-didecylferrocene was
achieved. Oxidation of 1,1'-didecylferrocene with Cr03 re-
sulted in the corresponding "ferrocenium" ion. However,
this alkyIferrocenium ion was not stable. Although unalky-
lated ferrocenium compounds are known to be stable, it ap-
pears our 1,1'-didecylferrocenium is not. Since alkylation
is necessary to provide solubility in the organic solvents
of the liquid ion exchange process, research on ferrocenium
compounds was terminated.
-25-
-------
REFERENCES
1. Nesbitt, J.B., "Removal of Phosphorus from Municipal
Sewage Plant Effluents", Engineering Research Bulletin
B-93, The Pennsylvania State University, February 1966.
2. Eliassen, R., and Bennett, G.E., "Anion Exchange and
Filtration Techniques for Wastewater Renovation",
JWPCF, 39, No. 10, R82-R91 (October 1967).
3. Garland, C.F., "Phosphorus Removal by High-Density,
Solids-Contact Tertiary Treatment", Paper presented at
FWPCA Workshop on Phosphorus Removal Technology,
Chicago, Illinois, June 26-27, 1968.
4. Bridges, D.S. and Rosenbaum, J.B., "Metallurgical Appli-
cation of Solvent Extraction", 1C Bureau of Mines 8139
(1962) .
5. Lewis, C.J., "Liquid Ion Exchange Processes", Chem.
Engineering 72, No. 14, 101 (1965).
6. Dunning, H.N., et al, "Removal of Refractory Contamin-
ants from Waste Water by Liquid Ion Exchange", present-
ed at 143rd Meeting ACS, Cincinnati, 1963.
7. Bock, R. and Burkhardt, P., Angew. Chem., J73_/114 (1961).
8. Schweitzer, G.K. and McCarty, S.W., J. Inorganic Nuclear
Chemistry, 27.' 191 (1965).
9. Genge, J.A.R. and Slamon, J.E., J. Chem. Soc., 1959 1459
10. Handbook of Chemistry and Physics, 50th Edition, The
Chemical Rubber Company.
11. Lohmann, D.H., J. Org. Metal, Chem., 4,(5) 382 (1965).
12. Vogel, M., Rausch, M. and Rosenberg, H., J. Org. Chem.
22, 1016 (1957).
13. Sulzbacher, M. and Bergmann, E., J. Org. Chem. 13, 303
(1948) .
14. Wilkinson, G., etc. J. Am. Chem. Soc., 74, 2125 (1952).
-27-
-------
15. Mason, J.G. and Rosenblaum, M., ibid 8J2, 4206 (1960)
16. Nesmeyanov, A.N. and Perevalova, F.G., Uspekhi Khimi
XXVII, Issue 1, 4-56 (1958).
17. Pavlik, I. and Zizek, V., Coll. Czech. Chem. Coitunun.
30, 669 (1965) .
-28-
-------
ADDENDUM - AMMONIA EXTRACTION
CHANGE IN SCOPE. OF CONTRACT NO. 14-12-590
We propose that the scope of the contract be changed from
phosphate extraction to ammonia extraction. The emphasis
would be on the extraction of ammonia from waste water that
has undergone treatment with lime. Thus, the objective
would now be to determine the feasibility of liquid ion ex-
change for extracting ammonia from waste waters.
The research program would be concentrated on developing a
liquid ion exchange reagent that selectively extracts am-
monia at elevated pH. Immediate emphasis would be on screen-
ing organic complexes or organic salts of transition metals
for this extraction. Such compounds have the'potential for
forming complexes with ammonia. For example, tridentate
complexes of copper would have a coordination site avail-
able for complexing ammonia. Therefore, they could be the
basis for a liquid ion exchange reagent that is selective
for ammonia.
The experimental program would be similar to .the one orig-
inally proposed for phosphate. A literature survey would
be made for functionalities that have potential for com-
plexing ammonia. Candidate compounds would be purchased
or, if necessary, synthesized for testing.
Ammonia extraction screening tests would be performed in
separatory funnels. Solutions of potential extractants in
an organic solvent would be contacted with an aqueous solu-
tion which simulates effluent which has been treated with
lime. Generally, this aqueous solution would contain 20
ppm of ammonia and appropriate inorganic"salts and cover a
range of pH. Analyses then would be applied to determine
the extent of ammonia extraction and selectivity.
Extraction isotherms would be drawn for compounds that show
promise. The data then would be evaluated to determine if
extractions are satisfactory for further consideration.
Satisfactory extraction would be generally viewed as at-
taining 1 ppm of ammonia in the effluent in several ex-
traction stages.
Methods for regenerating extraction activity would be check-
ed out on compounds that demonstrate satisfactory extraction
of ammonia. This also would be carried out in separatory
-29-
-------
funnels by treatment of the organic solutions that have been
loaded with ammonia. Means for ultimate disposal of the am-
monia would be considered in these experiments.
At this stage, the most promising compound would be checked
out on secondary effluent from the Anoka, Minnesota munici-
pal sewage plant.
Finally, this proposed program would be covered by the cost
and contract period stated previously in contract no. 14-
12-590. Also, the personnel involved would not change.
EXPERIMENTAL DETAILS
A literature survey was started for functionalities that
have potential for extracting ammonia.
Simultaneously, experiments were begun to screen transition
metal salts-of organic acids for ammonia extraction. Cop-
per salts were chosen as a starting point. Cupric ion is
known to complex with ammonia in the following manner.
Cu(H20)n++ + 4NH3 > Cu(NH3)4++ + nH20
A similar reaction was visualized for the cupric salt of an
organic acid, namely:
(RC09J .,Cu(H.,0) + nNH, > (RCO-) Cu (NH,) _ + nH-O
£ £* £ ll «3 £ 3 iT ^ """
The cupric salt of di-2-ethylhexyl phosphoric acid was pre-
pared and tested for ammonia extraction. A solution of the
cupric salt in toluene was shaken in a separatory funnel
with aqueous ammonia. The aqueous solution contained: 19
mg/1 NH3, 50 mg/1 Na+, 20 mg/1 K+, 10 mg/1 Mg++, and 20 mg/1
Ca++. Extractions with three different aqueous solutions
of pH 5.4, 9.5 and 11 were planned. Only the results at pH
5.4 are available. These show an extraction of 6% ammonia.
A cupric salt of napthenic acid also was prepared but not
tested yet for ammonia extraction. Attempts to prepare a
cupric salt of dioctadecyl phosphoric acid were unsuccess-
ful.
In preparation for the ammonia extractions, analyses were
set up for the various cations contained in the aqueous
solutions. For ammonia, a colorimetric analysis with Ness-
ler reagent was set up. Atomic absorption was employed for
the other cations.
-30-
-------
APPENDIX
LITERATURE SURVEY - PHOSPHATE EXTRACTANTS
As a base for future experimental work, a survey of the
literature (CA, up to and including Vol 67) was made. All
abstracts which contained material bearing on the extrac-
tion of phosphates were examined. Those deemed of interest
are included in the attached summaries.
The following conclusions have been arrived at:
1) Organometallic compounds of Group IV A (Ge, Sn, Pb)
and Group V A (As, Sb, Bi) appear to be of most im-
mediate value. Some compounds in these two groups
not only extract phosphates from water but also ex-
hibit selectivity for PO4 over SG>4~2.
2) Werner complexes which are water insoluble should
exhibit ion exchange capabilities. Selectivity of
such compounds is unknown.
3) A wide variety of compounds, clays, humates, lip-
ids, protein, appear to react with phosphates
through a bound metal ion such as Ca+2, Al+3/ Fe+3,
etc. It may be possible to use such a technique to
selectively extract phosphates from sewage.
4) A number of other possibilities are evident in the
abstracts but the above three areas appear to show
the most promise.
I. METAL CONTAINING EXTRACTANTS
A. Organometallic Compounds
Bock and Burkhardt (1-1) reported the extraction of Cl ,
Br~, I~, PO4~3, As04~3, Cr04~2, V04~3, and Se03~2 by
03SnOH in 0H. Sulfate and NO3~ are not extracted.
03PbOH in CHC13 was used (1-2) to extract Cl~, Br~, I~,
P04~3, As04 , SeO3~2 and others from neutral or slight-
ly acidic solutions.
Schweitzer, et al (1-3) used 03SnOH, 03PbOH, 0iSb(OH)2
and 03As(OH)2 to extract P043 and other ions from
solution.
-31-
-------
B. Werner Complexes
Furman and State (1-4) used (Co (NH3) 5NO J (NO3) 2 as a
precipitating agent for the phosphomolyBdate ion to
give {co(NH3)5NO^J H3PMo12041. (See also 1-5.)
Wolf and Forberg studied the reactions of a Cr (III)-
triethanolamine complex with a variety of anions, in-
cluding PO4 . (1-6)
A number of workers have studied the reactions of co-
balt-ammonia complexes with a number of ions, including
P04~3. None were used in solvent extraction systems.
(1-7, 8, 9, 10.)
C. Glass
Various types of glass strongly absorb PO* ions on
their surfaces. Baier (1-11) reports thai this absorp-
tion is caused by 1) hydrolysis of alkaline earth sili-
cates, borates, etc. to give them the alkaline earth
hydroxide which then reacts with the phosphate or 2) by
precipitation of difficultly soluble phosphate (i.e.,
Li-PO,) on the surface. The absorbed PO."3 is not read-
ily removed. (1-12)
D. Organic Compounds Containing Metals (not including or-
ganometallies) and Humates
Strong acid cation exchange resins loaded with trival-
erit metals react with PCK to form complexes. (1-13)
Ti+3 appeared to form the strongest complex.
The ability of soil to function as an ion exchange re-
sin for P04f3 is well documented. Chaminade (1-14)
showed that when humus is dissolved out of the soil
that the resultant material contains a large amount of
PO."3. We concluded that the PO4~3 is not held by the
organic portion of the humus but rather is bonded to
Ca*2 ions which in turn are bonded to the humus.
Chaminade also showed (1-15) that when Ca3(P04)2 is
precipitated in the presence of humates that Ca
is not formed but rather a Ca-humate-P04 complex.
A review (in Japanese) (1-16) discusses various proper-
ties of nitro-humic acids including its complex com-
pounds with phosphates.
-32-
-------
Roldan showed that the phosphate binding power of peat
can be improved by treating the peat with Ca(OH)~.
(1-17) ^
Kaila in an extensive study (1-18) isolated the effects
of various variables on the absorption of p by soil.
He concluded that Al content was the most important but
that Fe was also significant. Extractable Ca was not a
significant variable.
Weir and Soper (1-19) made Fe humates and found evi-
dence that non-carboxylic hydroxyls were important in
the binding of the Fe"^"3 to the humate.
II. CELLULOSIC MATERIALS
Veder and Pascha (II-l) studied the relative affinities of
ions for a material known as ECTEOLA-cellulose. They found
the order to be (descending affinity) OH~> HPO ~2> SO, 2>
N03~> Cl .
Aminocellulose (2.5% N) was found (II-2) to give the follow-
ing order of extractability: OAc~> N0o~> H2PO^ > Cl~> S04 ,
The material was effective only in acidic solutions.
III. LIPIDS
Lipids recovered from rat livers were converted to either
the Ca+2 or K+ form. CHCl-, solutions of the Ca+2 form ex-
tracted 70 times more PC>4~3 than the K lipids. The Ca"1"2
lipids gave increasing PC>4 extraction as the pH was in-
creased from pH 5.8 to 8.3. (III-l)
Phospholipids were shown to extract PO/ into CHC13 by
Kiyasu (III-2) and that microbial cofactor increased the
extraction.
IV. PROTEINS
In a study on the reaction of polyphosphates with proteins
and RNA, El'piner, et. al. (IV-1) used the polyphosphate
complex of toluidine blue. The pyrophosphate also complex-
ed with trypsin, inalin and myosin.
Muhlrad, et. al. (IV-2) found that at 0° C, myofibrils took
up "considerable" amounts of labelled P32 and that the P32
was found bound to the myosin and not to lipids. Denatured
myofibrils failed to take up the label.
-33-
-------
The reaction of ATP or PO, with human serum, egg albumin,
casein, globulin, myosin and muscle protein fractions was
investigated by Drabikowski (IV-3). The proteins were co-
agulated either at pH 3.6 or 5.8 and denaturization did not
affect the reaction. The effects of chemical modification
of the proteins were also studied. (Deamination, acetyla-
tion and esterification.)
Rogeness, et.al. (IV-4) showed that PMCG (N-methyl-3-piperi-
dinol cyclopentylphenylglycolate bonded to the phosphate
groups in lecithin and also with P0.~3.
32
Kokocbashvili, et.al. (IV-5) studied the extraction of P
(PC>4 ) with albumin and casein and found that the- bound
PCL"^ may be readily stripped by NaOH.
Mulder, et.al. (IV-6) theorized that the casein-phosphate
complex was actually calcium caseinate with adsorbed
Ca3(P04)2.
*3
The uptake of PO4 on casein was found to be greater in
the presence of Ca+2 than when no Ca+2 was present. (IV-7)
In an electrophoretic mobility experiment with RNase, a
marked binding of PO,~^ on the RNase was found. (IV-8)
Szorenyi (IV-9) also demonstrated the binding of PO, on
myosin.
-3
The reaction of salmine with PO4 was studied by Callanan,
et.al. (IV-10) and Ui, et.al. (IV-11).
Courtois, et.al. studied the precipitation of conamandin
(sweet almond protein) with PCK""^. (iv-12)
V. ADSORPTION.OF PO4~ ON CLAY
The adsorption and release of P04 by clays and soils has
been extensively studied. The general consensus is that
the P04~3 reacts with Al-~, Fe+3, Ca+2, Mg+2 or K+ which
occur on the surface of the particles. (V-l to V-9)
VI. ELECTRON ACCEPTORS
Sukhorukov, et.al. (VI-1) studied the interaction of P04
and various phosphate containing molecules (AMP, ADP, ATP,
etc.) and electron acceptors such as tetracyanoethylene,
p-benzoquinone, methylene blue, ribofalvine, chloranil,
etc.
-34-
-------
VII. FOAM FRACTIONATION
R. B. Grieves, et.al.has studied the removal of PO^ from
solutions by foam fractionation with ethylhexadecyldimethyl-
ammonium bromide. (VII-1 to VI1-3)
VIII. MISCELLANEOUS
The extraction of phosphoric acid with alcohols and amines
from wet acid production has been extensively studied.
(VIII-1 to VIII-3) These extractants generally are used
for concentrated or highly salted solutions.
The precipitation of various phosphates with both biologi-
cal and non-biological bases has been studied (VIII-4).
They appear to be effective only in acid systems, however.
Phenothiazine and imipramine based drugs (tranquilizer
type) form precipitates with phosphates. (VIII-5 to VIII-
6)
Phosphates have been determined by forming the molybdophos-
phate ion, making the salt with an organic base and extrac-
ting the compounds into a water immiscible solvent. (VIII-
7 to VIII-10)
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A v'Ct*.v»-. -:.' Number
I r\ -, Subject Field & Group I
! 05F- I
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
| Organization
General Mills Chemicals, inc.
i TI.'.'B
FEASIBILITY OF LIQUID ION EXCHANGE FOR EXTRACTING
PHOSPHATE FROM WASTEWATER
Q !
16
Ditsch, LeRoy,
Swanson, Ronald, and
Miiun, Albert J.
Project Designation
17010 EAP
2] Note
1 Citation
2*5 ! Descriptors (Starred First)
-^ Phosphates*.. Solvent Extraction*, Tertiary Treatment*, Ion Exchange*,
Separation Techniques, Anion Exchange, Water Purification, Water
Treatment, Sewage Treatment, Extraction
25 j Identiliars (Starred First)
Liquid I6n Exchange*, Secondary Effluent*
r.,'! .4bstract-p_ variety of organic compounds were screened for utility in ex-
d"5t:tin9 inorganic phosphate from water by the liquid ion exchange process.
Orgenometallic compounds, metal salts of di-2-ethylhexyI phosphoric
^ci.a and ferrocenium compounds wer,e investigated. Only certain organo-
raetallics showed significant activity and this activity appeared to be cor
cen'trated in minor, constituents present in the samples. More specifically,
tribenzyltin compounds, possibly the hydroxide or its acid "salts, were
active in selectively extracting phosphate in the presence of chloride and
sulfate.
(Milun - General Mills)
A. J. Milun
Institution
General Mills Chemicals, Inc,
SEND .'C WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. c. 20240
« CPO: 1'H 0 - :J5 8-^ j ..
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