Note: Descriptions are shown in the official language in which they were submitted.
CA 02221703 2006-O1-31
~%~ 96138220 P~'IY~S9610~943
QROCESS F~~R RECOVERY OF METRL ~OnIS
FIELD OF THE INVENTION
The present invention relates to water-soluble metal-binding polymers and in
the
use of such water-soluble metal-binding polymers in a process for selective
separation of metal ions from aqueous streams. The metal ions can further be
concentrated and removed or recovered. In such a process, the metal ions can
be
bound to the polymer via electrostatic andlor complexation or chelation
processes and
then treated by a separation means, such as ultrafiltration, to reduce water
content and
other unbound molecules and ions. This invention is the result of a contract
with the
Department of Energy (Contract No. W-7405-ENG-36j.
BACKGROUND OF THE INVENTION
Water-soluble polymers are well laiown for the retention or recovery of
certain
metal ions from solutions under certain conditions, e.g., certain pH
conditions (see,
e.g., Pure and Applied Chemistry, Vol. 52, pp. 1883-1905 (1980), Talents, vol.
36,
No, 8, pp. 861-863 (1989), and U.S. Pat. No. 4,741,831, May 3, 1988 to
Grinstead).
Additionally, higher molecular weight varieties of the water-soluble polymers
such as
polyethyleneimine have been used as coating on, e.g., silica gel, for
separation and
recovery of metal ions. However, the selectivity of the polymer for target
metals due
to competition from competing or interfering ions within solutions can present
unique
challenges.
Among the various aqueous streams that may need to be approached in the
selective separation of metal ions are brines such as sea water and brine-
containing
process streams, body fluids such as urine, electroplating waste waters such
as rinse
baths, textile waste waters, actinide-processing waste waters, catalyst-
processing
waste waters. electronics-processing waste wata~s, geothermal waters, oil-well
waters,
ore leachate process streams, oxoanion recovery, from such mining acid
production
activities, mining waste waters from acid drainage of mimes, cooling tower
streams.
general waste water streams from water treatment facilities. contaminated
aquifer
waters or drinking water streams, and the like. Each of these systems presents
a
different and unique challenge due to the varying composition of that
particular
aqueous stream.
CA 02221703 1997-11-19 - .
WO 96138220' PGT/US96/08143
2
It is an object of the present invention to provide a process of selectively
separating a target metal or metals from an aqueous solution.
It is still a further objective of the invention to provide a process of
selectively
separating a target metal from aqueous streams including competing ions, such
, .
streams including electroplating-processing waste water streams, textile-
processing
waste water streams, actinide-processing waste water streams, catalyst-
processing ''
waste water streams, electronics-processing waste water streams, ore-
processing waste
streams, mining waste water streams, general waste water streams and the like,
and
other aqueous streams such as body fluids, brine solutions, cooling tower
waters,
drinking water and the like.
SUMMARY OF THE INVENTION
To achieve the foregoing and other objects, and in accordance~with the
purposes
of the present invention, as embodied and broadly described herein, the
present
invention provides a process of separating selected metal ions from an aqueous
solution including contacting an aqueous solution with a reaction solution for
a time
sufficient to form a water-soluble polymer-metal complex, the reaction
solution
including an effective amount of a water-soluble polymer having nitrogen-,
oxygen-
or sulfur-containing groups capable of binding selected metal ions, said water-
soluble
polymer having a molecular weight of greater than a first preselected level
and
characterized as essentially free of molecular weights less than a second
preselected
level, treating the aqueous solution by membrane separation means effective to
separate water and low molecular weight materials having a molecular weight of
less
than said first preselected level from the aqueous solution while retaining a
concentrated aqueous solution including materials having a molecular weight of
greater than said first preselected level, said materials having a molecular
weight of
greater than said first preselected level including said water-soluble polymer
and said
water-soluble polymer-metal complex, contacting the concentrated aqueous
solution
with a material selected from the group consisting of an acid, a reducing
agent, and a
complexent under conditions effective to release the selected metal ions from
the
water-soluble polymer-metal complex and to form regenerated water-soluble
polymer,
and, removing the released selected metal ions by a secondary membrane
separation
CA 02221703 1997-11-19
WO 96!38220 PGT/US96/08143
3
means effective to separate the released selected metal ions from said
concentrated
aqueous solution including said regenerated water-soluble polymer.
In another embodiment of the invention, the concentrated aqueous solution
including said regenerated water-soluble polymer is recycled as reaction
solution for
contact with additional selected metal ion-containing aqueous solution.
In another embodiment of the invention, the concentrated aqueous solution
including the said water-soluble polymer-metal complex is oxidatively destroy
to
allow for recovery of the metal.
BRIEF DESCRIhTION OF THE DRAWINGS
FIGURE 1 illustrates a schematic diagram of an ultrafiltration process using a
concentration mode of operation for metal-recovery from metal-containing
aqueous
waste streams.
FIGURE 2 illustrates a schematic diagram of an ultrafiltration process using a
diafiltration mode of operation for metal ion recovery from a metal-loaded,
water-
soluble polymer.
DETAILED DESCRIPTION
The present invention is concerned with the separation of various metals,
e.g.,
toxic metals and/or precious and/or nuisance metals from aqueous streams.
Also, the
present invention is concerned with recovery of the various metals after
separation.
After separation, such metals can be analyzed or recovered from the aqueous
stream.
In some instances, such ultra-low levels of a particular metal may be present
that it
cannot be detected by traditional analytical techniques and the present
invention can
serve as a preconcentration step prior to subsequent analysis for that
particular metal.
Numerous aqueous streams containing one or more particular target metals for
separation also include a variety of competing cations, anions, and/or organic
material. To successfully separate the target metal or metals, the selected
water-
soluble polymer or polymers must have high selectivity for the target metal or
metals
in the presence of all the other competing cations (other metal ions) and
anions
(various counter ions) in solution.
Among the numerous aqueous streams including one or more particular target
metals for separation are included brine solutions, urine, municipal waste
waters.
electroplating or metal finishing process streams, mining process and waste
waters.
CA 02221703 1997-11-19 ~,
WO 96/38220 r PCT/US96/08143
4
photofinishing and/or,printing waste waters, electronics industry waste
waters,
actinide processing waste waters, waste waters involving various oxoanions,
textile
industry waste waters, cooling tower waters, industrial catalyst-containing
waste
waters, drinking and contaminated aquifer waters, nuclear industry waste
waters, oil-
well waters and general industrial waste waters. Each aqueous stream can
present a
different set of problems in separation of target metals because of the
presence of
other ~n_aterials.- Yet,-in-eat instance-the~netal sep a.atiu~~ ~r retrwai and
a ien tiie-
recovery of target metals is an important problem to that particular area or
industry.
Various particular examples or embodiments of aqueous streams containing
target
metals are set out below.
In one embodiment of the present invention, the target metals for separation
or
recovery can exist within a brine solution, e.g., seawater, salt-mine brine,
etc. Often,
it is desirable to separate the target metals for recovery or disposal. The
typical
composition of sea water is shown below in Table A and includes large amounts
of
sodium and magnesium chloride complicating the separation or recovery.
Table A. Typical seawater composition (pH 7.9 to 8.4).
Metals
Cd 0.07
Co 0.3
Cr 0.25
Cu 3
Fe 100
Mn 25
Zn 4
Mg 0.74 x 106
Na 6.1 x 106
U 3.3 (ppb as
U02)
A salt brine can typically have a composition as shown below in Table B.
Recovery of specific metals from brine solutions is a common industrial,
analytical. or
environmental need.
CA 02221703 1997-11-19
WO 96/38220 PCT/L1S96/08143
S
Table B. Sample of simulated salt brine solution from Carlsbad, NM.
Materials Amount in g/L
MgC12.6H20 584.28 g
NaCI 200.25 g
KCl 114.39 g
' Na2S04 12.41 g
Na2Bq.07~ l OH20 3.91 g
CaCl2 3.32 g
NaHC03 ~ 1.93 g
NaBr 1.04 g
LiCI 254.27 mg
RbCI 54.73 mg
SrCl2'6H20 30.69 mg
KI 26.60 mg
FeC13~6H20 25.73 mg
CsCI 2.63 mg
HCl (1N) 0.30 ml
In another embodiment of the present invention, the target metals for
selective
separation or recovery or concentration can exist within body fluids such as
urine.
For example, it can be desirable to test the urine of workers from certain
jobs for the
presence of metals such as actinides (e.g., plutonium) or toxic metals (e.g.,
lead).
Generally, the salt and organic content of a body fluid, e.g., urine, is high,
somewhat
similar to that of seawater. A typical composition for a synthetic or
simulated urine is
shown below in Table C.
CA 02221703 1997-11-19 -
WO 96!38220 ~ PGT/US96/08143
6
Table C. Composition of simulated urine.
Components g/k~ Component g~kg
Urea 16.0 NaH2P04'H20 2.73
NaCI 2.32 CaCl2'2H20 0.63
KCl 3.43 Oxalic acid 0.02
Creatinine 1.10 Lactic acid 0.094
Na2S04 (anhyd.) 4.31 Glucose 0.48
Hippuric acid 0.63 Na2Si03'SH20 ' 0.071
NH4Cl 1.06 Pepsin 0.029
Citric acid 0.54 CaC03'H20 0.42
-
MgS04 (anhyd.) 0.46
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in actinide or fission product-containing
waste
streams, e.g., at a waste water treatment facility at a nuclear facility or
nuclear plant.
The salt content of the waste stream can be high and is quite variable. This
can
complicate the separation of the actinides and or fission products to the
required
discharge limits. A typical composition for a waste stream of the Los Alamos
National Laboratory (LANL) aqueous waste water treatment facility is shown
below
in Table D.
CA 02221703 1997-11-19
WO 96138220 PCT/US96/08143
7
Table D. Composition of simulated waste water from site TA-50 treatment
facility at LANL.
Ion Concentration Salts Concentration
Molar (Ml (~rams/5 L)
Ba2+ 1.4 x 10-7 Ba(N03)2 0.0001
Ca2+ 2.9 x 10-4 Ca(N03)2~4H200.7070
Cl- (a) 1.1 x 10-3 NaCI (CuCl2) 0.0017
Cu2'~' 9.5 x 10'7 CuC12~2H20 ~ 0.0017
F- 1.1 x 10'4 NaF 0.0504
Fe3+ 4.6 x 10'6 Fe(N03)2 0.0195
Mg2+ 7.1 x 10'5 MgS04 0.0916
Ni2+ 8.0 x 10-5 NiC12~H20 0.0020
Zn2'+' 1.9 x 10-6 Zn(N03)2 0.0059
Nd3+ 4.8 x 10-9 Nd(N03)3~6H20trace
NH3 1.2 x 10-'1 NH40H 0.0510
N02- 2.3 x 10'6 NaN02 0.0017
N03- (b) 1.1 x 10'2 NaN03 6.3751
PO43- 4.3 x 10-6 Na2HP04 0.0063
K+ 9.0 x 10-4 KOH 0.5459
Na+ (c) 1.0 X 10-2 NaOH . 0.9320
(a)Chloride
from both
NaCI and
CuCl2.
(b)Present
as zinc,
calcium,
and iron
nitrate
salts.
(c)Present
from NaCI,
NaF, NaN03,
NaN02,
and NaOH.
In another embodiment of the present invention, the target metals for
selective
separation or recovery include zinc and nickel from zinc and/or nickel
electroplating
or metal finishing dilute process streams. Such a stream also can generally
contain
materials such as ammonium salts, borate salts. sulfate salts, fluoroborate
and/or
chloride salts, organic chelators, e.g., tartrates or citrates, and metal
impurities such as
iron, copper. cadmium, lead, aluminum, and chromium making selective
separation of
the zinc and/or nickel difficult. Not only is it desirable to remove all these
metal ions
from the waste stream to render the total aqueous waste stream nonhazardous
for
discharge to a sewer system. it is desirable to selectively recover those
metal ions,
CA 02221703 1997-11-19 w .
WO 9(/38220 ~ PCT/US96l08143
8
e.g., zinc and nickel, so they can be reused in plating baths. Table E lists
the typical
composition of a variety of zinc and nickel containing plating baths.
Table E. Composition of typical zinc and nickel containing electroplating
baths*.
Bath Zinc/ Nickel/Chloride/Sulfate!NH_dOH, Additives/Boric
L L L L aOH, or L cid/L
N a
NH~SOz=/L
Zn/Ni 9.2 18 134 g 0 56.6 g 50 mL 20.4
g g g
Alloy (NH4+) surfactant
Watts 0 87g 13g 114g 0 O.Sg 37g
Nickel Na-lauryl
sulfate
Nickel 0 105 0 0 344 g 0.37 g 30 g
g
Sulfamate (NH2S03 anti-pitting
)
Basic 9 g 0 0 0 75 g (NaOH)0 0
Zinc
Bright 43 0 78 g 0 15 g 5% v/v 0
Acid g
Zinc (NH40H) brightener
T 1 ypical nnse waters would be expected to be approximately 100 times
dilution from
these values.
In another embodiment of the present invention, the target metals for
selective
separation or recovery include a variety of metal ions from electroplating or
metal-
finishing process streams. As exists for zinc and nickel metal finishing
streams, such
a stream also can generally contain materials such as ammonium salts, borate
salts,
fluoroborate salts, sulfate salts, and/or chloride salts, organic chelators,
e.g., tartrates
or citrates, and metal impurities making selective separation of the metal ion
of
interest difficult. Not only is it desirable to remove all these metal ions
from the
waste stream to render the total aqueous waste stream nonhazardous for
discharge to a
sewer system, it is desirable to selectively recover those metal ions, e.g.,
tin, copper,
etc.,-so they can be reused, (e.g., in plating baths). Table F gives the
components of a
variety of typical electroplating or metal finishing baths. There are a large
variety of
these types of baths including single metal electroplating and electroless
processes.
There are a variety of metal alloy baths also, including brass and bronze
which are
CA 02221703 1997-11-19
WO 96/38220 9 PCT/US96/08143
copper and zinc and sometimes cadmium alloys; lead-tin, tin-copper, tin-
nickel, and
tin-zinc. Precious metals such as gold, silver, palladium, ruthenium,
platinum,
rhodium are also commonly used in plating operations. All these baths are
composed
of complex mixtures from which the metal ion of interest can be recovered.
Table F. Components of some typical plating baths.
Bath Tvne Components
Cadmium Cadmium fluoborate, fluoboric
acid, boric
acid, ammonium fluoborate,
licorice
Copper Copper fluoborate, fluoboric
acid
Tin Tin-fluoborate, fluoboric acid,
boric acid,
stannous sulfate, sulfuric
acid, cresol
sulfonic acid, beta napthol,
gelatin
Chromium chromic acid, sulfuric acid
Lead Lead fluoborate, fluoboric
acid, boric
acid, gelatin, hydroquinone
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in mining waste waters either from acid mine-
water
drainage or form actual mining processes. It is desirable to remove the
controlled
metals from the aqueous stream both as an environmental protection measure
and/or
to recover metal value from the aqueous stream. To recover the metal value it
is
necessary to selectively recover metals from other plentiful metals that occur
in the
aqueous stream. The composition of an example acid mine drainage stream, the
Berkeley Pit in Butte, Montana, is shown below in Table G with the parts per
million
(ppm) of the respective element being the average value of four samples taken
at
different depth profiles in the pit.
CA 02221703 1997-11-19
WO 9/38220' PCT/L1S96/08143
Table G. Composition of Acid mine drainage water at the Berkeley Pit, Butte
Montana.
Element ppm
Ca 47g
Mg 418
Na 69
K I8
Si02 97.5
Fe 875
Mn 186
A1 279
B 0.40
Cd 1.67
Cu 184
Li 0.26
Mo 0.058
Ni I .06
Sr 1.36
Ti 0.078
V 0.11
Zn 528
As 0.53
Co 1.75
Cr 0.055
Cl I2.0
S04 7643
N03 as 0.27
N
F 2I.1
pH 2.68
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in photofinishing and printing industrial
waste waters.
It is desirable to recover the precious metals from the aqueous stream both as
an
environmental protection measure and/or to recover metal value from the
aqueous
stream. To recover the metal value it is necessary to selectively recover
metals from
other plentiful materials that occur in the aqueous stream. The composition of
an
example photofinishing waste stream is shown below in Table H. Some specific
organic compounds can also include acetate, benzyl alcohol, and formalin. The
water-
soluble polymer must have high selectivity and be able to compete with the
thiosulfate
to recover the metal values. Some processes can contain ammonium phosphate and
CA 02221703 1997-11-19
WO 96/38220 PGT/US96/08143
11
sodium nitrate also. The presence of other toxic metals such as chromium along
with
silver requires the removal of all toxic metals and the recovery of the silver
for its
metal value.
Table H. Simulated mix of effluent from Kodak Ektaprint 2
chemicals (Bleach-fix, Low-flow wash, and final wash).
Material Amount ner Liter
~H4)2s203 1.35 mL as 58% solution
ammonium fernc 1.25 mL as 1.56 M solution
ethylenediaminetetraacetic
acid
Na2S03 0.05 g
silver 160 mg
Kodak Ektaprint 2 developer 3.5 mL
replenisher
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in waste water from the electronics industry.
It is
desirable to recover the precious metals from the aqueous stream both as an
environmental protection measure and/or to recover metal value from the
aqueous
stream. To recover the metal value it is necessary to selectively recover
metals from
other plentiful materials that occur in the aqueous stream. Trace impurities
such as
lead and nickel need to be removed from the waste streams also. The
compositions of
some example electronics waste streams that contain copper are shown below in
Table
I. Other aqueous streams can include gold from the manufacture of connectors
and
printed circuits. Impurity metals could include copper, silver, cobalt, lead,
and nickel.
CA 02221703 1997-11-19
WO 96138220' PGT/US96108143
12
Table I. Typical formulations of acid copper plating used in circuit board
applications.
Bath 1: .
_
copper Fluoborate
Fluoboric acid
lead (major impurity problem)"'
Bath 2:
Copper sulfate
- Sulfuric acid
chloride
proprietary additive
(e. g., thiourea, dextrin)
nickel and lead can be problems-
Bath 3:
copper pyrophosphate
potassium pyrophosphate
potassium nitrate .
ammonium hydroxide
Addition agent
In another embodiment of the present invention, the target metals for
selective
separation and recovery can exist in low levels in actinide processing waste
waters.
After processing nuclear material for the recovery of plutonium and uranium,
the
remaining aqueous waste stream contains low levels of trivalent actinides and
lanthanides. For proper waste management it is desirable to separate the long-
lived
actinide metal ions (e.g., americium) from the shorter-lived lanthanide metal
ions
(e.g., europium). Currently, such processes as liquid-liquid extraction are
used to
separate all the actinides from these waste streams. The lanthanides are
simultaneously extracted with the trivalent actinides. The composition of an
example
process stream containing actinides and lanthanides waste stream is shown
below in
Table J. Use of water-soluble polymers provides efFcient methods for
separating
these trivalent actinides from the trivalent lanthanide ions.
CA 02221703 1997-11-19
WO 96138220 PCT/US96/08143
13
Table J. Composition of a typical actinide and lanthanide containing waste
stream from light wafer reactors.
Element Quantity,g/L
La 0.25
Y 0.09
Nd 0.82
Pr 0.24
Ce 0.49
Sm 0.18
Gd 0.03
Eu 0.03
Am 0.03
Cm 0.007
U 0.04
Np 0.004
Pu 0.008
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in a variety of industrial waste waters that
produce or
use oxoanions (e.g., molybdium, technetium, chromium, etc.) and/or waters that
naturally contain oxoanions from runoff or natural environmental conditions
(e.g.,
selenium, arsenic, etc.). It is desirable to remove the metal ions from the
aqueous
stream both as an environmental protection measure and/or to recover metal
value
from the aqueous stream, and/or for proper waste management practices. To
recover
the metal value it is necessary to selectively recover metals from other
plentiful
materials that occur in the aqueous stream. The composition of an example of a
technetium-containing waste stream from the Hanford Tanks, in Hanford,
Washington
is shown below in Table K, where it might be desirable to recover technetium.
CA 02221703 1997-11-19 ..
WO 9fs/38220 ' PCT/US96/08143
14
Table K. Double-Shell Slurry (D55) simulant formulation from Hanford tanks in
Washington.
Material Source Grade Molari
NaOH Baker Reagent 0.783
T\ . 1 r 1 -
Technical 0.486
NaN03 Baker Reagent 1.498
NaN02 Baker Reagent 0.857
Na2C03 Baker Reagent 0.385
~TVa2SOq. Baker Reagent 0.031
NaCI EM Reagent 0.093
N~ Baker Reagent 0.080
Na3P04~H20 Baker Reagent 0.114.
Ca(N03)2~4H20 MallinckrodtReagent 0.002
K2C~4 Baker Reagent 0.014
Na3(Citrate)~2H20Baker Reagent 0.073
Li Tc04 ~ ____
5.0 x 10-
mTc --- ___~_ <10-
Table L contains the typical concentration of a tungsten-containing
electroplating
bath where it is desirable to recover tungsten, as an oxoanion, in the
presence of
nickel.
Table L. Composition of nickel-tungsten alloy electroplating bath.
Reagent Quanitity in g/L*
Na2 W04 66
NiSOq.~6H20 36.8
Ammonium citrate 97.7
~' 1 he quantity in rinse waters will be generally diluted approximately 100
times over
these values.
In another embodiment of the present invention, the target metals for
selective
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
separation or recovery can exist in textile processes or waste streams.
Generally,
these aqueous streams can contain fiber particles, organic dyestuffs, process
chemicals, and free or bound metal ions. Common metals that are used include
copper and chromium. Typical compositions for textile waste streams have the
characteristics shown below in Table M. Other metal-containing waste streams
can
include copper that is used in the production of dyestuffs for example in the
manufacture of aromatic diazonium groups using the Sandmeyer reaction.
Table M . Typical characteristics of textile process streams.
Sample Sample A ~ Sample B Sample C
pH 10.7 4.5 4.5
Primary heavy metal Cu (575 ppm) Cu. (1000 Cr (1000 ppm)
(mg/L) ppm)
COD (mg/L)* --- 65,000 65,000
BOD (mg/L)* -- 250 250
Suspended solids (%) --- 1-2 1-2
Total Solids (%) ~ - 5-6 5-6
Water Hardness (mg/L)- soft (50-70)soft (50-70)
(mg/L as CaC03)
* Organic dyestuffs are mostly azo and diazo dyes in these examples.
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in cooling tower waters and cooling waters or
waste
streams. Generally, the aqueous streams can contain corrosion products such as
nickel and cobalt and corrosion inhibitors such as chromium. Depending upon
the
type of cooling tower other metal ions could be present in low levels such as
calcium,
magnesium or iron. If the cooling water comes from nuclear power plants, other
metals such as strontium and silver could be present including activation
products or
spallation products. It is desirable to remove metals from these streams as
some are
hazardous and others cause scaling problems.
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in catalyst-containing industrial waste
water. It is
desirable to recover the precious metals from the aqueous stream both as an
environmental protection measure and/or to recover metal value from the
aqueous
stream. 'To recover the metal value it is necessary to selectively recover
metals from
other materials that occur in the aqueous stream. The composition of an
example
catalyst containing waste stream is shown below in Table N. The presence of
other
toxic metals along with the primary metal requires the removal of all toxic
metals and
CA 02221703 1997-11-19 --,
WO 96/38220
PCT/US96/08143
16
the recovery of, e.g., copper, nickel, platinum, palladium, or rhodium, for
its metal
value.
t aate 1V. Composition of several typical catalyst-containing waste streams.
Industry Type Metals found in Stream
Auto catalytic converters Platinum, copper, rhodium,
palladium
Chemical manufactures Nickel, copper, cobalt, tin
In another embodiment of the present invention, the target metals for
selective
separation or recovery can exist in drinking waters as dilute contaminates
that arise
-from sitting in, for example, leaded pipes or containers that have lead
solder or from
,aquifer water that has become contaminated from hazardous metal runoff or
from
some other mechanism. It is desirable to remove the toxic metal ions from the
aqueous stream before it is used for human consumption. To remove the metal
ion to
very low levels for drinking water standards requires that the water-soluble
polymers
have very high binding constants such that they can remove metals to very low
levels.
The concentration maximums of controlled metal ions for drinking water
standards
are shown below in Table O.
Table O. EPA drinking water standards for controlled metals.
Metal Ion Concentration (m
/I>.)
arsenic 0.1
cadmium 0.005
chromium 0.1
copper 1.3
lead 0.015
mercury 0.002
nickel 0.1
selenium 0.05
uranium 0.02
alpha emitter 15 pCilL
The water-soluble polymers useful in practicing the present invention are
synthetic water-soluble polymers, i.e., they are not naturally occurring water-
soluble
polymers such as starch, cellulose, and the like and do not involve modified
naturally
occurring water-soluble polymers. The water-soluble polymers used in the
present
invention generally include a nitrogen-, oxygen-, or sulfur-containing group.
CA 02221703 1997-11-19
WO 96/38220 PGT/US96/08143
17
Exemplary of the water-soluble polymers used in the present invention are
polyalkyleneimines such as polyethyleneimine and modified polyalkyleneimines,
i.e.,
polyalkyleneimines such as polyethyleneimine where the water-soluble polymer
includes functionalization selected from the group consisting of carboxylic
acid
groups, ester groups, amide groups, hydroxamic acid groups, phosphoric acid
groups,
phosphoric ester groups, acylpyrazolone groups, aza-crown ether groups, oxy-
crown
ether groups, guanidium groups, thiolactam groups, catechol groups,
mercaptosuccinic acid groups, alkyl thiol groups, and N-alkylthiourea groups.
In
addition to polyethyleneimine as the basic structure of many of the water-
soluble
polymers, other water-soluble polymer structures with nitrogen-containing
groups
such as poly(vinylamine), polyvinylpyridine, poly(acrylamide), and
poly(allylamine),
can be used. Also, water-soluble polymer structures with oxygen-containing
groups
such as poly(vinylalcohol) or oxygen- and nitrogen-containing groups such as
polyvinylpyrrolidone can be used. The amine backbones can also be
permethylated to
give permethylated polyethyleneimine, permethylated polyvinylpyridine,
permethylated polyallylamine, or permethylated polyvinylamine. Water-soluble
polymers can be constructed from vinyl monomer polymerization reactions to
give a
number of groups, copolymer of acrylamide or acrylic acid and bis-phosphoric
esters
and acids. Water-soluble polymers with metal binding properties can be
obtained
from ring-opening reactions, e.g., the treatment of polypyrrolidone with base
or
hydroxylamine.
Exemplary of suitable functionalized water-soluble polymers are the reaction
product of polyethyleneimine and an arylalkylhaloacetylpyrazolones such as
phenylmethylchloroacetylpyrazolone or dimethylchloroacetylpyrazolone to yield
a
phenylmethylacetylpyrazolone-substituted or dimethylacetylpyrazolone-
substituted
polyethyleneimine, the reaction product of polyethyleneimine (polyallylamine,
polyvinylamine) and a halocarboxylic acid such as bromoacetic acid or
chloroacetic
acid to yield an amino-carboxylate-substituted polyethyleneimine
(polyallylamine,
polyvinylamine), the reaction product of polyethyleneimine (polyvinylamine,
polyallylamine) and phosphorous acid and formaldehyde to give a phosphoric
acid
substituted polyethyleneimine (polyvinylamine, polyallylamine), the reaction
of
polyethyleneimine and a monohydroxamic acid of succinic acid to give a
hydroxamic
acid substituted polyethyleneimine, the reaction of polyethyleneimine with
acrylamide
or ethylacrylate to give an ester or amide substituted polyethyleneimine, the
reaction
of vinylalcohol with a crown alcohol to give an oxycrown substituted
vinylalcohol,
the permethylation of polyvinylpyridine or polyethyleneimine or polyvinylamine
or
polyallylamine to give the respective permethylated polymers, the ring opening
of
polypyrrolidone with hydroxylamine to give the hydroxamic acid polymer, the
CA 02221703 1997-11-19
WO 9/38220 . PCT/CTS96108143
18
copolymerization of a beta-bisphosphonic acid or ester with acrylamide or
acrylic acid
to give a copolymer, the reaction of polyethyleneimine with a beta-
bisphosphonic acid
or ester to give bisphosphonic acid or ester polyethyleneimine, and the
reaction
product of polyethyleneimine and a haloacetylaza crown material such as a
chloroacetylaza crown ether to yield an aza crown ether-substituted
polyethyleneimine.
When the polyethyleneimine is functionalized, care must be taken to control
the
level of functionalization as solubility problems at certain pH values can
exist
depending upon the type of functional groups and backbone used. The water-
soluble
polymers used in the present process preferably maintain their water
solubility over
the entire pH range of, e.g., pH 1 to 14. Preferably, any polyethyleneimine
used in the
present invention includes primary, secondary and tertiary amines.
Bisfunctionalization can be realized for primary nitrogens allowing for
multidentate
character of some of the chelating groups. The polyethyleneimine is a branched
polymer, giving it a globular nature and high charge density which partly
accounts for
its uniqueness in the polyamine family of polymers. This highly branched
character
also allows for better binding site interactions with metal ions within the
polymer.
Other polyamines, i.e., polyvinylamine and polyallylamine, can be used as
backbones,
and are composed of all primary nitrogens, but they are linear polymers and if
over
functionalized can lead to insolubility in different pH ranges.
The use of prepurified (sized) polymer is critical to the process. Use of pre-
purified polymer in the functionalization of, e.g., polyethyleneimine, has the
advantage that reagents used in the functionalization steps are not lost on
low
molecular weight polyethyleneimine that will be lost in subsequent
purification of the
functionalized polymers. Further, it gives an extra margiri of assurity that
there will
be no polymer leakage during the use of the polymers in the process.
Conditions in the preparation of the water-soluble polymers are important to
assure that there is no detectable leakage through the ultrafiltration
membrane during
the process. Several factors are important in aiding the presizing of the
water-soluble
polymers; the polymer concentration, the pH value, and the ionic strength at
which the
polymers are presized are all important. Because water-soluble polymers can
aggregate in solution and because the polymers can expand or contract in size,
conditions that effects these tendencies should be controlled. For example, it
is
known that polyethyleneimine can change it average size by 60% between a basic
and
acidic solution (larger in the acidic solution and smaller in basic). Thus, _
polyethyleneimine should be prepurified at the pH where its size is smallest
to further
assure the smaller fragments are remover from the larger fragments (at a pH of
about
10-11 ). Other polymers because of either their neutral, anionic, or cationic
nature will
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
19
have different optimum pH values for prepurifying depending upon the pH that
gives
the smallest polymeric volume in solution. The ionic strength of a solution
can also
effect the polymeric volume in solution similarly to pH effects. If polymer
concentration are too high in solution they will aggregate, again effecting
the potential
ability of obtaining polymers thaf are not going to leak through the membranes
during
the process.
The prior art in the preparation of polyethyleneimine or other water-soluble
polymers for use in metal separations has been quite vague in how it is
prepared and
treated for use in ultrafiltration techniques. At best, literature procedures
report
polymer solutions were prepared by prefiltering through the same size
molecular
weight cutoff (MWCO) membrane that was used in the experiment, with no detail
as
to pH or concentration or ionic strength. It is believed that this partially
provides the
reason why the general concept of polymer filtration has been preliminarily
tested and
proposed at the laboratory bench scale for over 10 years, yet the process has
not been
commercially practiced.
The present process to purify polyethyleneimine is unique in that the
purification
scheme does not clog the ultrafiltration membranes. In contrast, some
polyethyleneimine manufacturers have been unable to develop a purification
technique for sizing the polymer using ultrafiltration without severely and
irreversibly
clogging the membranes. Note that one other main use of polyethyleneimine is
as an
adhesive and polyethyleneimine is known to bind to many surfaces, especially
cellulose and anionic surfaces. Polyethyleneimine has been reported to be
fractionated by size using GPC (size exclusion chromatography), precipitation,
and by
exhaustive dialysis. Average molecular weight determinations were performed by
osmometry, ultracentrifugation, viscometry, and light scattering techniques.
Generally, the literature refers to determining the average molecular weight
instead of
producing fractions that do not pass an absolute molecular weight cutoff.
The water-soluble metal-binding polymer can be used in several potential
compositions for selective separation of metal ions. There can be a single
polymer
that will bind selectively with only one metal ion over all other ions and
materials
under the conditions of the process. Separation is achieved by binding that
metal ion
to the water-soluble polymer and then using a separation technique such as
ultrafiltration to remove the water and other materials from the polymer. The
polymer-bound metal ion is thus concentrated. The polymer-bound metal can be
released from the polymer by a variety of processes as shown in the following
equations:
M(P) + H' ______> Hp + M+ (eq. 1 )
CA 02221703 1997-11-19
WO 96138220 ' PCT/US96/08143
M(P) + L ________> ML + (P) (eq. 2)
or
M(P) + e- _______> MX + (p) (eq. 3)
where M is the metal ion, (P) is the water-soluble polymer, L is a competing
complexant, H+ is a proton, x is the valent state of the metal , and a is an
electron for
an oxidation change reaction. Where the metal is released by a proton (eq. 1 )
or by a
competing molecular ligand (eq. 2), the polymer-free metal ion is recovered by
a
diafiltration process. In some instances, the metal ion may be so tightly
bound to the
polymer that it is more desirable to heat process the concentrate to destroy
the
polymer (incineration, hot acid digestion, smelting, etc.) and recover the
metal.
Optionally, for waste management purposes it may be desirable to solidify the
polymer-bound metal, e.g., in a grout or cement material, such that it passes
EPA
toxic leach tests (TCLP).
Another potential composition can include a single polymer that will bind with
a
combination of metal ions under the process conditions. Separation and
selectivity is
realized by binding that combination of metal ions then using a separation
technique
such as ultrafiltration to remove the water and other materials from the
nnivmPr_mPtal
_ ___
complexes. The polymer-bound metals can be selectively released from the
polymer
by a variety of processes as shown above in equations 1, 2, and 3. Where the
selected
metal is released by protons (eq. 1 ) or by a competing molecular ligand (eq.
2), the
polymer-free metal ion can be recovered by a diafiltration process. Stripping
of the
polymer is repeated until all the desired metals have been selectively
recovered.
Again in some instances, the metal ions may be so tightly bound to the polymer
that it
~is more desirable to heat process the concentrate to destroy the polymer to
recover the
metals. Optionally, for waste management purposes it may be desirable to
solidify the
polymer-bound metal, e.g., in a grout or cement material, such that it passes
EPA
toxic leach tests (TCLP).
Still another composition uses a polymer formulation (two or more polymers of
same molecular weight range) blended in such a ratio and with such
functionality to
have the desired selectivity that binds a combination of metal ions under
certain
conditions of pH, counter ion, and/or ionic strength. Separation is achieved
by
binding the metal ions to the water-soluble polymers and then using a
separation
technique such as ultrafiltration to remove the water and other materials from
the
polymer. The mixed polymer-bound metals are thus concentrated and can be
further
purified by washing with a clean solution in a diafiltration process to remove
any final
impurities. The polymer-bound metals can be selectively released from the
polymers
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
21
by a variety of processes as shown in equations 1, 2, and/or 3. When the
process uses
equation 1 and/or 2, the water-soluble polymers may be selectively stripped of
the
respective metal or group of metals by, e.g., appropriate pH control into a
range
whereat one polymer is stripped of its particular metal while the second water-
soluble
polymer retains its particular metal as a water-soluble polymer-bound metal.
The
second and subsequent polymers can be stripped of the remaining metal ions as
desired for the separation process and the regeneration of the polymers for
further
reuse in the separation process.
Still another composition uses a polymer formulation (two or more polymers of
different molecular weight range) blended in such a ratio and with such
functionality
to have the desired selectivity that binds a combination of metal ions under
certain
conditions of pH, counter ion, and/or ionic strength. Separation is achieved
by
binding the metal ions to the water-soluble polymer and then using a
separation
technique such as ultrafiltration to remove the water and other materials from
the
polymer. The mixed polymer-bound metals are thus concentrated and can be
further
purified by washing with a clean solution in a diafiltration process to remove
any final
impurities. The polymer-bound metals can be selectively released from the
polymers
by a variety of processes as shown in equations 1, 2, and/or 3. When the
process uses
equation 1 and/or 2, the water-soluble polymers may be selectively stripped of
the
respective metal ions or group of metal ions by, e.g., appropriate pH control
into a
range whereat one polymer is stripped of its particular metal while the second
water-
soluble polymer retains its particular metal as a water-soluble polymer-bound
metal.
The second and subsequent polymers can be stripped of the remaining metal ions
as
desired for the separation process and the regeneration of the polymers for
further
reuse in the separation process. Alternatively, since the water-soluble
polymers are of
different size ranges, it is possible to remove the metal from one polymer by
the
equations 1 to 3, and to separate the smaller polymer containing one type of
functionality from the larger polymer with a different type of functionality.
One of
the functionalities is chosen to bind the metal ion of interest so tightly
that the
polymer that contains that functionality and the bound metal ions can be size
separated from the other size polymer(s).
Another composition can include a single polymer or formulation of polymers
that will bind with a single metal ion or a combination of metal ions under
the
conditions of the method. Separation and selectivity is realized by binding
that
combination of metal ions to the water-soluble polymer or polymers, then using
a
single pass separation technique such as ultrafiltration to remove the water
and other
materials from the polymer-bound metals. The polymer-bound metals are further
concentrated to dryness or near dryness onto a flat ultrafiltration membrane.
The
CA 02221703 1997-11-19 ---
WO 9/38220' PCT/US96l08143
22
membrane is either dissolved or digested in appropriate medium or leached with
an
appropriate acid or ligand to totally recover the metals that were on the
membrane.
The recovered solution which constitutes a concentrate of selected metal ions
from the
original solution can then be analyzed using appropriate analytical instrument
or wet
chemistry techniques. ~ - .
Another composition can include a single polymer or formulation of polymers
that will bind with a single metal ion or a combination of metal ions under
the
conditions of the process. Separation is achieved by binding the selected
metal ions to
the water-soluble polymer or polymers and then using a separation technique
such as
biphasic liquid-liquid extraction to remove other materials and unbound metal
ions
from the aqueous. polymer solution. The metals that are unbound to the polymer
and
.go into the organic or second phase are separated from the polymer-containing
aqueous phase by standard phase separation techniques, e.g., mixer settlers,
liquid
extraction membranes, or centrifugal contactors, etc. The metals can be back-
extracted from the second phase to another aqueous phase for recovery
purposes. The
polymer can be regenerated from the aqueous stream by first concentration
ultrafiltration followed by diafiltration. This process can be done in reverse
by back
extracting the metal ion of interest from a biphasic system using aqueous
solutions of
the water-soluble polymer.
Generally, the concentration of the~water-soluble polymer is from about 0.001
weight to volume percent to about 25 weight to volume percent of final mixed
solution, more preferably from about 0.001 weight to volume percent to about 5
weight to volume percent of final solution. It is sufficient, and in some
cases
desirable, to have only enough polymer in solution such that the molar ratio
of
polymer to metal ions in solution is one. Using high concentrations of the
water-
soluble polymer can most often result in a lower flux or flow during an
ultrafiltration
stage. The use of high polymer concentration can also cause an aggregation
effect
where no or little metal ion binding occurs to the polymer when the metal ion
encounters a high initial concentration of polymer. During the ultrafiltration
stage the
polymer and metal bound polymer concentration can often become quite high and
in
the case where the solution goes to near dryness it can approach 90% of the
weight of
the concentrate.
After the solution containing the water-soluble polymer is contacted with the
aqueous metal-containing solution for a sufficient period of time to form
water-
soluble polymer-metal complex, separation of the water-soluble polymer-metal _
complex is preferably accomplished by ultrafiltration. Ultrafiltration is a
pressure
driven separation occurnng on a molecular scale. As a pressure gradient is
applied to
a process stream contacting the ultrafiltration membrane, liquid including
small
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
23
dissolved materials is forced through pores in the membrane while larger
dissolved
materials and the like are retained in the process stream. Pressure gradients
can be
created, as desired, from the use of vacuum systems, centrifugal force,
mechanical
pumping, and pressurized air and/or gas systems (e.g., nitrogen).
In a continuous or semicontinuous ultrafiltration stage, the solution
containing
the water-soluble polymer-metal complex is passed through an ultrafiltration
unit as
shown in Figure 1. Referring to Fig. 1, the process for displacing cyanide ion
from
the metal-cyanide complex by the water-soluble polymer~includes the following
steps:
a metal-cyanide-containing feed solution is added via line 1 to a solution of
the water-
soluble polymer in tank 2. This reaction mixture is conveyed via line 3 pump
4, and
line 5 to separations means 6. Generally, the separations means 6 preferably
is an
ultrafiltration membrane, having a MWCO less than the molecular weight of the
water-soluble polymer. The separation is normally accompanied by recirculating
the
mixture through the membrane device having a throttle valve 7 in line 8 to
maintain a
pressure of less than 60 psi ~in the membrane unit with 25 psi being
preferred. The
aqueous solution which permeated through the membrane is collected as effluent
9
which contains the free cyanide. The cyanide can be destroyed or the cyanide
solution
reused.
Both the water-soluble polymer-metal complex and any free, i.e., uncomplexed,
water-soluble polymer are optimally retained by the membrane of the
ultrafiltration
unit, i.e., they do not pass through the membrane as permeate, while the
solvent and
unbound materials, i.e., water and small molecules, can pass through the
membrane as
permeate. The retention of solute during ultrafiltration depends on the
membrane
pore size. Though the molecular weight cut-off (MWCO) is generally defined as
the
molecular weight of spherical uncharged solute which is 90 percent retained by
the
membrane, preferably in the present invention less than 0.001% (<1 ppm) of the
polymer can penetrate the membrane. This low penetration is achieved by pre-
purification of the water-soluble polymer material during their preparation or
synthesis. By use of ultrafiltration, the water-soluble polymer-metal complex
can be
separated from the solution whereafter the metal can be separated from the
water-
soluble polymer-metal complex for recovery, recycling, or disposal as desired.
Generally, for these applications the polymer or polymer formulation is
prepared such
that there is no detectable breakthrough of polymer through the membrane. This
is
CA 02221703 2006-O1-31
WO 96!38220 24 PCTNS96108143
achieved by prepurifying the water-soluble at one MWCO and running the process
at
a MWCO less than that MWCO. Polymer leakage can be detected or monitored in
several ways. First, the total organic carbon of the permeate can be
determined.
Since the polymers contain substantial amounts of carbon, the polymers can be
detected to the 1 ppm range of carbon. The second method is a color test where
the
polymer can bind copper and cause a color change and enhancement. This can be
detected to the <1 ppm level.
Generally, there are two modes of operation in ultrafiltration. The first is a
batch
or concentration mode, as shown in Figure 1, where the volume in the retentate
is
reduced by simple filtration. The second mode is diafiltration with the
ultrafiltration
unit as shown in Fig. 2. Referring to Fig. 2, the process for recovering metal-
ions
from the metal-loaded water-soluble polymer includes the following steps: a
metal ,
stripping solution, e.g., dilute mineral acid, is added via line 10 to a
solution of the
water-soluble polymer in tank ~. This reaction mixture is conveyed via line 2
pump _1~,, and line 14 to separations means 15. Generally, the. separations
means I S
preferably is an ultrafiltration membrane, having a MWCO less than the
molecular
weight of the water-soluble polymer. The separation is normally accorapanied
by
recirculating the mixture through the membrane device having a throttle valve
~6_ in
line ~ to maintain a pressure of less than 60 psi in the membrane unit with 25
psi
being preferred. The aqueous solution which permeated .through the membrane is
collected as ei~luent ~8 which contains the metal concxntrate. The metal ions
can be
reused or treated for proper waste management.
During diafiitration, as permeate is generated, solute-free liquid, i.e.,
water or
apprapriate solution, is added to the retentate at the same rate as the
permeate is
generated thereby maintaining constant volume within the ultrafiltration unit.
In
diafiltration, the lower molecular weight species in solution are removed at a
maximum rate when the rejection coeff cient for that species equals zero. The
ultrafiltration process can be performed in a variety of configurations, for
example, in
a simple concentration mode, a concentration mode followed by diafiltration
mode, or
a concentration mode slip streamed continuously to a diafiltration mode. In
some
modes of operation biphasic extraction occurs prior to the ultrafiltration.
CA 02221703 2006-O1-31
_..,
WO 96138220 P(jT/US96108143
In the present process, the ultrafiltration unit can generally consist of
hollow-fiber
cartridges with membrane material having a 1,000 MWCO to 1,000,000 MWCO
preferably 10,000 MWCO to 100,000 MWCO. Other membrane configurations such
as spiral-wound modules, stirred cells (separated by a membrane), thin-channel
devices, centrifuge units (separated by a membrane) and the like may also be
used
although hollow-fiber cartridges are generally preferred for the
continuous/semicontinuous process filtration units. For analytical
applications for
preconcentration purposes stirred cells and centrifuge ultrafiltration units
are
preferred. Small hollow-fiber cartridges also can be used for continuous
preconcentration for analytical applications. Among the useful ultrafiltration
membranes are included cellulose acetate, polysulfone, and polyamide membranes
such as polybenzarnide, polybenzaraidazole, and polyurethane.
The use of ultrafiltration for separation is further described in Kirk Othmer:
Encyclopedia of Polymer Science and Engineering, 2nd Ed., vol. 17, pp. 75-104,
1989,
which may be referred to for further details.
Generally, the water-soluble polymers used in the present process have
molecular
weights of from greater than 1,000 to about 1,000,000, and preferably from
greater
than 10,000 to 100,000. Above molecular weights of 1,000,000, some polyraers
tend
to lose solubility, while with polymers below molecular weights of about 1000,
retention by suitable ultrafiltration membranes can present problems such as
low flux
rates. More preferably, the water-soluble polymers used in the present
invention have
distinct molecular weight ranges, i.e., they have been sized to exclude
molecular
weights below a certain value and optionally above a certain value. This
sizing can be
accomplished by filtering the particular water-soluble polymer thmugh
polysulfone
ultrafiltration membranes such as e.g., UFP-10-C-5 membranes from AG
Technologies, Corp. with a particular molecular weight cutoff value. These
resultant
compositions, i.e., sized water-soluble polymers have particularly exceptional
utility
in the separation of metals. Generally, a MWCO of 1000 difference between the
first
higher range and the second lower range should be sufficient to meet the needs
of the
present process. For example, the polymers could lie sized or pre-purified at
20,000
MWCO and then ultrafiltration membranes of 19,000 MWCO used in the process.
The present description and specific examples shown hereinafter detail a
process
CA 02221703 1997-11-19 -
WO 96/38220 ~ 26 PCT/C1S96/08143
based on the presently commercially available ultrafiltration membranes which
at this
time are limited to suitable polysulfone membranes with 10,000 MWCO, 30,000
MWCO and 100,000 MWCO from AG Technologies, Inc. Other MWCO's are
presently unavailable but when available would provide additional options to
the
present process.
The water-soluble polymers, e.g., the sized water-soluble polymer
compositions,
may further be useful in the separation of organic moieties or biological
moieties in a
process akin to affinity chromatography except that the process would be a
single
phase process rather than a column chromatography resin based process. For
example, as for metal binding, there is an equilibrium constant (K) for the
equation
E + S <_> ES
where S is a substrate and E is an enzyme (or any biological macromolecule
that can
bind to a substrate) to yield an enzyme-substrate complex (ES). The size of
the
equilibrium constant (K) determines the complex stability or strength. When K
is
large, the complex should be able to be formed nearly quantitatively in one
contact or
stage. Once the complex is formed, assuming either S or E is attached to a
water-
soluble polymer, a separation and concentration from species that are in the
solution
that have very small K values or no binding ability should be possible using
ultrafiltration as the physical separation process similar to that described
above for
metals separation. Once the unbound components have been diafiltered from the
system, the ES complex can be dissociated with appropriate reagents and either
E or S
can be recovered from the system. This process or affinity polymer filtration
is
related to the commonly used process of Affinity Chromatography where solid
resins
are used in a similar fashion in a chromatographic mode. Similarly, if E and S
are
small organic molecules that have special affinities for each other, small
organic
molecules can also be separated. For example, if S is a phosphonate ester, it
can bind
with carboxylic acids such as acetic acid or formic and effect a separation.
Initially, evaluation of water-soluble polymer size, substrate linker arm
lengths,
appropriate linker arms, and the presence of other macromolecules within the
system
that would require separating is conducted. Then, using standard linking
chemistry
that is currently used for binding substrates to gels (agarose or Sepharose,
etc.) that
are used in affinity chromatography, appropriate substrates are bound to e.g.,
CA 02221703 2006-O1-31
WO 96138220 2 ~ PCT/US96108143
polyvinyl alcohol or polyethyleneimine (PE1). For example, the inhibitor for
Staphylococcal Nuclease can be attached to a spacer arm connected to PEI by
linking
a carboxylic acid (e.g., bromoacetic acid) to the primary amine in PEI using a
coupling reagent, (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) at pH 4.7.
Then,
the primary aniline amine group can attach the inhibitor, pdTp-aminophenyl, by
displacement of the bromo group on the carboxylic acid. Through these types of
standard linking chemistries a variety of substrates can be attached (P.
Cuatrecasas, J.
Biol. Chem. volume 245, page 3059, 1970). When a mixtiue containing the enzyme
to be purified is then contacted with the water-soluble polymer containing the
substrate, binding will take place. The impurities will be removed by
diafiltration, the
enzyme concentrated by ultrafiltration, and the enzyme recovered by
appropriate
displacement chemistry followed by diafiltration to recover the enzyme.
The water-soluble polymers can be of the type described by Smith et al.,
Canadian Patent Application File Number 2,221,618, filed May 30, 1996,
entitled
"Water-Soluble Polymers and Compositions Thereof , and can be used for the
displacement of cyanide ions from metal-cyanide complexes as described by
Smith et
al., in U.S. Patent No. 5,643,456 issued July 1, 1997, entitled "Process for
the
Displacement of Cyanide Ions from Metal-Cyanide Complexes".
Though the thrust of this inve~ion has been the use of water-soluble metal-
binding polymers to bind, remove, and recover metal ions from aqueous
solutions, it
is also possible that metal ion impurities can exist in organic solutions.
Such organic
solutions can include glycols from radiators, used oils from automobiles, and
other
organic solvents that become contaminated with rrletal ions. With minimal
modifications to the polymers to enhance their organic solubility, and with
improvement in membrane technology such that a variety of organic solutions
can be
easily ultrafiltered, this same process can be employed for application to the
binding,
removal and recovery of metals from organic solutions.
CA 02221703 1997-11-19 ---
WO 96/38220 ' PCT/LTS96/OS143
28
The present invention is described in more detail in the following examples
which are intended as illustrative only, since numerous modification and
variations
will be apparent to those skilled in the art. Examples A-BB show the
preparation of
PEI, PEI derivatives, and other water-soluble chelating polymers used in the
present
process, while Examples 1-25 show the process of separating metals from
various
aqueous streams using the example polymers.
EXAMPLE A (polymer A)
The polyethyleneimine (PEI) was prepared as follows. Crude polyethyleneimine
(obtained from BASF as Polymin Waterfree PEI and as PEI homopoly~rier P) was
obtained in two molecular weight ranges. The Polymin Waterfree polymer was
reported to have a molecular weight in the range of 10,000 to 25,000, while
the PEI
homopolymer P was reported to have a molecular weight range of 70,000 to
750,000,
depending upon the method of molecular weight measurement. In reality both of
these polymer had a broad molecular weight range and had material that passed
through ultrafiltration membranes that had 10,000 MWCO and 30,000 MWCO and
100,000 MWCO. These polymers from BASF were highly branched having a
primary to secondary to tertiary nitrogen ratio of approximately 1:2:1.
To demonstrate the effect of pH on polymer size a 1 wt/vol % solution of
polymin water free was adjusted with acid or base to span the pH region
between 2
and 10. The solutions were diafiltered through a 30,000 MWCO membrane with
permeate samples taken periodically to determine polymer concentration using
the
copper method described below. The concentration of polymer permeating the
membrane at a high pH was considerably greater (0.014% at 15 min) than that
passing
through at lower pH values (0.003% at 15 min). The largest difference occurred
between pH 10 and 8, with the sequential lowering of the pH leading to smaller
effects on the polymer size, with very little difference in size at a pH of 4
and 2. Due
tL2~hl~sir~t~iatic c'._h_~,gPin prtl j r-~iW; p~viyetiiylc uciWii'ic way
purified by
diafiltration at a relatively high pH value (pH 10.8 for PEI).
The polymer was purified using hollow-fiber membranes prepared by a special
extrusion process (ultrafiltration membrane cartridges prepared from
polysulfone
material in a special homogeneous fiber construction) such that the
microporous
structure does not have macrovoids. Membranes such as UFP-10-C-5 (currently
manufactured by AG Technologies. Corp.) were the only type of material found
at
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
29
this time to purify polyethyleneimine and allow for membrane washing to
recover full
flux rates after substantial use.
The polyethyleneimine was diluted in water to approximately 10-15% by weight.
The pH was about 10.5 upon dissolution of the polyethyleneimine. The solution
was
diafiltered using 10,000 MWCO, 30,000 MWCO, and 100,000 MWCO membranes
(keeping the volume constant) until 6-7 volume equivalents of water were
passed
through the system at less than or equal to 25 PSI. Following the
diafiltration step,
the solution volume was reduced approximately 85% to concentrate the polymer.
The
remaining water was removed under vacuum and mild heat to yield colorless,
viscous
purified polyethyleneimine. Thus, with polymin waterfree 25% by weight PEI
came
through the 10,000 MWCO membrane, 10% by weight PEi came through the 30,000
MWCO and not the 10,000 MWCO membrane, and 65% by weight was retained by
the 30,000 MWCO membrane (this fraction referred to hereinafter as polymer
Aa).
With the Polymin P polymer 16% by weight passed through the 10,000 MWCO
membrane, 3% by weight was less than 30,000 MWCO and greater than 10,000
MWCO, 5% by weight was less than 100,000 MWCO and greater than 30,000
MWCO, and 76% by weight was greater than 100,000 MWCO (this fraction referred
to hereinafter as polymer Ab). The material resulting from the retentate from
the
30,000 MWCO (polymer Aa), when filtered on a 10,000 MWCO membrane, gave no
detectable passage of the polymer through a 10,000 MWCO membrane using a
copper
test developed to detect less than 1 ppm of polyethyleneimine polymer.
Similarly for
material collected at greater than 100,000 MWCO (polymer Ab) when tested on a
30,000 MWCO membrane no detectable polymer was observed in the permeate. For
some applications the polymer concentrate did not require drying but could be
concentrated to a workable volume as subsequent functionalization reactions
were
performed in water.
The copper test involved placing 0.5 mL of the test sample into a 10 mL
volumetric flask, adding 0.5 mL of a copper acetate solution (1.99 g of copper
acetate
diluted to 100 mL with 0.01 M HCl), 1.0 mL of pH 5.8 buffer (0.6 mL of acetic
acid
diluted to 100 mL with deionized water with addition of 11.2 g of anhydrous
sodium
acetate and sufficient sodium acetate or acetic acid to adjust pH to 5.8), and
deionized
water to dilute to mark. This solution was mixed well. A standard curve for an
UV-
CA 02221703 1997-11-19 ---
WO 96/38220 ' 3~ PCT/(TS96/08143
VIS spectrophotometer was prepared using 0.01 %, 0.02%, 0.05%, and 0.08
wt/vol%
solutions of PEI. A reagent blank was used as a reference sample and read at
284
nanometers.
The specifications for the ultrafiltration membrane included hollow-fibers of
a
material to which polyethyleneimine does not adhere to any significant extent,
i.e.,
detrimental effect on flux. The routine operational pH range of the cartridges
fell
between 2 and 12 with the ability to process solutions down to a pH of 0 to 1
for
limited periods of time (30 min) without damage to the cartridges. Minimum
flux
rates were 0.01 gallons/min/sq.ft. at 25oC and at a transmembrane pressure of
1 S PSI
with a solution of 5% by weight branched polyethyleneimine (Polymin Waterfree
10,000-25,000 MW). Original flux rates of the cartridge were readily
regenerated
after use by a simple cleaning process of a 10 minute flush with water
followed by 30
min with 500 ppm hypochlorite and rinsing with water. The cartridge had at
least a
minimum operational pressure of 50 PSI at 25oC: The cartridges had the ability
to be
operated at temperatures up to 80oC.
EXAMPLE B (polymer B)
An amino-carboxylic acid containing water-soluble polymer of the structure:
Cl'l2Cl-12 Cf-(ZCO2f-1
N
HC02CFiz/ ~COzH
was prepared on polyethyleneimine (PEI, Polymin Waterfree used as received
from
BASF, i.e., unpurified)) using a molar ratio of carboxylic acid moiety to sub-
units of
CH2CH2N within the PEI of about 4 to 1 as follows: A solution of potassium
hydroxide (260.4 g) in water (400 mL) was added dropwise over a period of 30
minutes to a solution of polyethyleneimine (25.02 g) and bromoacetic acid
(322.4 g)
in water (500 mL) keeping the temperature below 50° C. After the
addition was
complete, the solution was stirred at reflux for 3 hours. The solution was
cooled to
room temperature then diluted to 2 liters with deionized water. The pH of the
solution
was adjusted to 5.8 using potassium hydroxide or hydrochloric acid. The
polymer
CA 02221703 1997-11-19
WO 96/38220 31 PGT/US96/08143
was purified by diafiltration collecting five volume equivalents of permeate
using
hollow fiber cartridges with a 30,000 MWCO. The retentate solution was then
concentrated and the remaining water was removed under reduced pressure. The
residual material (referred to hereinafter as polymer B) was dried in a vacuum
oven at
60° C overnight to give 50.78g of a light tan brittle solid. IR (ATR):
1630 cm 1
(C=O). Elemental Analysis Found: C, 32.58%; H, 4.97%; N, 8.54%; O, 28.99%.
EXAMPLE C (polymer C)
A partially functionalized carboxylic acid containing water-soluble polymer of
the following structure:
(CH2CHz ~ CH2CH2NH)n
CH2CH2
N
H~2~2~ ~C~~2H
was ~renared on nolvethvleneimine BASF. Polvmin Waterfree. purified as in
Example A, >30,000 MWCO) using a molar ratio of carboxylic acid moiety to sub-
units of CH2CH2N within the PEI of about 0.5 to 1. The source of carboxylic
acid
was chloroacetic acid in one case and bromoacetic acid in another case. The
procedure, as in Example B, was followed except for the differences noted
here.
Elemental Analysis Found: C, 44.72%; H, 8.35%; O, 29.3%. The polymer is
referred
to hereinafter as polymer C.
A partially functionalized carboxylic acid containing water-soluble polymer
was
prepared on polyethyleneimine (BASF, Polymin P, unpurified, 70,000 to 700,000
MW range) using a molar ratio of carboxylic acid moiety to subunits of CH2CH2N
within the PEI of about 0.5 to 1. The source of carboxylic acid was
chloroacetic acid.
The procedure as in example B was followed except for differences noted here.
The
material was diafiltered through several molecular weight cutoff membranes
such that
a molecular weight fraction of greater than 10,000 MWCO but less than 30.000
MWCO and a molecular weight fraction greater than 30,000 MWCO but less than
100,000 MWCO (referred to hereinafter as polymer Ca) and a fraction greater
than
100,000 MWCO (referred to hereinafter as polymer Cb) were obtained.
CA 02221703 1997-11-19 "'~
WO 96f38220 ~ PCT/US96/08143
32
EXAMPLE D (polymer D)
A fully functionalized phosphoric acid containing water-soluble polymer of the
structure:
i H2P(O)(OH)2
(CH2CH2 N CHZCH2N)n
CH2CH2
N
(OH)2(O)PCH ~ \ CH2P(O)(OH)2
was.prepared on a polyethyleneimine (Polymin Waterfree from BASF, used as
received, i.e., unpurified). Polyethyleneimine (2.50 g, about 0.058 mole
monomer
equivalent) was dissolved in 6 M hydrochloric acid (80 mL) followed by the
addition
of solid phosphorous acid ( 19.0 g, 0.29 mole) at room 'temperature. The
homogeneous solution was brought to reflux followed by the dropwise addition
of
formaldehyde (38 mL of a 37% solution, 0.47 mole) over a hour. After the
addition
was complete, the solution was stirred at reflux for an additional hour. The
heat was
removed and the flask allowed to sit overnight at room temperature. The sticky
solid
precipitate was collected by decantation of the liquid from the flask. The
solid was
dissolved in water and adjusted to pH 6.8 with sodium hydroxide. The solution
was
purified by diafiltration through a 30,000 MWCO membrane. A total permeate
volume of 3.5 liters was collected. The solution was then concentrated to
approximately 150 mL. After removing the water under reduced pressure, the
residue
(referred to hereinafter as polymer D) was dried under high vacuum at
60°C
overnight to give 6.3 g of a light yellow solid. Elemental analysis found: C,
22.46%;
H, 5.48%; N, 8.70.%; P, 16_88%.
CA 02221703 2006-O1-31
WO 96138220 PCTIUS96/08143
33
EXAMPLE E (polymer E)
A partially funetionalized phosphoric acid containing water-soluble polymer of
the structure:
N
t~htol~6/ \ct~toxr~
was prepared on a polyethyleneimine. Polyethyleneimine (BASF Polymin -
Water&ee,10,000-25,000 MW and pre-purified by diafiltration through a 30,000
MWCO cartridge prior to use as in example A, 25Øg, 0.58 mole monomer
equivalent) was dissolved in 6 M hydrochloric acid (300 mL) followed by the
addition
of solid phosphorous acid (47.56 g, 0.58 mole) at room temperature. The
homogeneous solution was brought to reflux followed by the dropwise addition
of
formaldehyde (23.53 mL of a 37% solution, 0.29 mole) over a hour. After the
addition was complete, the solution was stirred at reflux for an additional
hour. The
heat was removed and the flask allowed to sit overnight at room temperature.
The
reaction mixture was diluted with water to 2 liters and the pH adjusted to 6.8
using
potassium hydroxide. The solution was purified by diafiltration through a
30,000
MWCO. A total permeate volume of 6 liters was collected. The solution was then
concentrated to approximately 200 mL. After removing the water under reduced
pressure, the residue (refen~ed to hereinafter as polymer E) was.dried under
high
vacuum at 60°C overnight to give 32 g of a light yellow solid.
Elemental analysis:
%C, 30.18; %H, 8.42; %N,13.95; %P,14.05; %K, 0.15.
A partially func6onalizred phosphoric acid containing water-soluble polymer
was
prepared on polyethyleneimine (BASF, Polymin P, unpurified, 70,000 to 700,000
MW range) using a molar ratio of phosphoric acid moiety to subunits of CH2CH2N
within the PEI of about 0.5 to 1. The procedure as in example E above was
followed
except for differences noted here. The material was diafiltered through
several
molecular weight cutoffmembranes such that a molecular weight fraction of
greater
than 10,000 MWCO but less than 30,000 MWCO and a raolecular weight fraction
greater than 30,000 MWCO but less than 100,000 MWCO (referned to hereinafter
as
CA 02221703 2006-O1-31
WO 96/38220 PCf/US96b8143
34
,polymer Ea) and a fraction greater than 100,000 MWCO (referred to hereinafter
as
polymer Eb) were obtained.
EXAMPLE F (polymer F)
An acylmethylpy~zolone containing water-soluble polymer of the structure:
tcx~~- ~ -c~
0
_-cf cat,
N
H N/
~t
was prepared on a polyethyleneimine as follows: A precursor (4-chloroacetyl-
1.3-dimethyl-pyrazol-5-one) was first prepared. To a 500 mL three-neck round
bottom flask fitted with a reflux condenser, mechanical stirrer, and a
pressure
equalizing additional funnel,1,3-dimethylpyrawi-5-one (6.03 g, 53.84 mmole)
and
dioxane (55 mL, distilled from sodium metal) were added. The mixture was
heated to
40-50oC to dissolve the suspended solids and give a light yellow solution. The
reaction mixture was cooled to 30-35oC followed by the addition of Ca(OH)2
(7.98 g,
107.68 mmole). After 10 minutes of stirring, chloroacetyl chloride (6.82 g,
59.22
mmole) in dioxane (20 mL) was added over a period of 30 minutes. The reaction
mixture was heated at reflex for 24 hours. The reaction mixture was filtered
while hot
and the filter cake washed with hot dioxane (2 x 20 mL) followed by methanol
(2 x 20
mL). The solvent was removed under reduced pressure yielding 14 g of the
product
as the calcium salt. The solid was passed through a column of Dowex-50W
strongly
acid cation exchange resin. Water was removed under reduced pressure leaving a
white solid which was further dried under vacuum at 60oC over night to give
the
1
product (61%, m.p.-161-165o C) as a white solid in 61% yield. H NMR (CDCl3,
ppm) 84.38 (s), 3.60 (s), 2.41 (s). 13C NMR (CDCl3, ppm) 15.6, 32.7, 45.7,
101.0,
146.0, 159.3, 188.2
The polymer was then prepared as follows: PEI polymer (Polymin Waterfree
4.00 g, prefiltered through a 30,000 MWCO cartridge as in example A, was
dissolved
in water (100 mL) and brought to reflex. The 4-chloroacetyl-1,3-dimethyl-
pyrazole-
5-one precursor from above (4.40 g. 23.33 mmol) and triethylamine (4.68 g,
46.25
CA 02221703 2006-O1-31
WO 96138220 PCT/US96/08143
35
mmol) dissolved in water (20 mL) were added dropwise over a 10 minute period.
The
solution was stirred at reflux for 2.5 hours at which time it turned from
yellow to
orange and then to red. After cooling to room temperature, the material was
diluted
with deionized water to a volume of 1 liter and the polymer purified by
diafiltration
through a 30,000 MWCO cartridge collecting S liters of permeate. The water was
removed under reduced pressure and the residue (referred to hereinafter as
polymer F)
was dried under vacuum at 60oC to give a reddish-orange, brittle solid (5.49
g, 73%).
IR ( ATR): 3435 (N-H), 1626 (C~) cm 1. Elemental Analysis: C, 53.85%; H,
8.65%; N, 24.59%; 0,12.98%.
EXAMPLE G (polymer G)
An acylphenylpyrazolone containing water-soluble polymer of the structure:
x
fC_ ~ ~~-'N'~' O
c~-N~ac~-cue' cu,
~N
N
I
Pti
was prepared on a polyethylencimine as follows. PEI (1.00 g, polymin
waterfree,
unpurified) and triethylamine (2.34 g, 23.1 mmol) were dissolved in chloroform
(30
mL) and brought to reflux. The 1-phenyl-3-methyl-4-chloroacetyl-pyrazole-5-
one,
prepared following the proccdures of Jensen in ACTH Chem. Scand.,1959, 13,
1668
and Olcafor et al. in Synth. React. Inorg. Met. Org. Chem.,1991, 21(5), 826,
(3.18 g,
5.8 mmol), in chloroform (10 mL) was added dropwise to the solution resulting
in the
precipitation of a tan solid. After stirring for 1.5 hours, the mixture was
cooled and the
suspended solid collected by filtration. The solid was dissolved in water (400
mL),
adjusted to a pH of 3.0, and the solution diafiltered using a 30,000 MWCO
cartridge.
The water was removed under reduced pressure and the residue (referred to
hereinafter as polymer G) dried in a vacuum oven at 60° C to give 1.56
g as a red
brittle solid. IR (ATR): 3430 (N-H), 1630 (C=O) cm I .
EXAMPLE H (polymer H)
A hydroxamic acid containing water-soluble polymer of the structure:
CA 02221703 1997-11-19 - -
WO 9638220 ~ PCT/US96/08143
36
--( CHZCH2 N CH2CH2 N
CH2CH2 NCCH2CNH(OH)
O O
was prepared on polyethyleneimine (PEI). Hydroxylamine hydrochloride (2.78
g, 39.97 mmol) was dissolved in methanol (15 mL). Potassium hydroxide (2.24 g
,
39.97 mmol), dissolved in methanol (10 mL), was added dropwise to the
hydroxylamine solution. The mixture was stirred for 1 hour after which the
precipitated potassium chloride was collected by filtration. To the filtrate
was added
sordid succinic anhydride (4.00 g, 39.90 mmol). The mixture was stirred at
room
temperature for 3 hours. The solvent was removed under reduced pressure
leaving a
white sticky solid. The solid was allowed to sit under anhydrous diethyl ether
for one
hour. The solid was collected by filtration giving 4.80 g of the
monohydroxamic acid
of succinic acid as a white solid with a melting point of from 72-82°.
This solid (1.00 g, 7.51 mmol), dicyclohexylcarbodiimide (DCC) (1.54 g, 7.51
mmol) and a catalytic amount of 4-(dimethylamino)pyridine were dissolved in
tetrahydrofuran (THF) (I O mL). After stirring for 24 hours at room
temperature, the
solution was filtered to remove the DCU (dicyclohexylurea) byproduct. This THF
solution was added to a methanolic solution containing polyethyleneimine (1.29
g,
29.95 mmol monomer eq., prepurified as in Example A, >30,000 MWCO), a small
amount of phenolphthalein, arid enough sodium methoxide to make the solution
pink.
The solution was stirred for 5 hours. The solvent was evaporated and the
product
purified by dissolving in water and diafiltered through a 30,000 MWCO hollow-
fiber
membrane. Evaporation of the water followed by drying under vacuum at
60°C gave
1.21 g of a white polymer (referred to hereinafter as polymer H). Testing with
the
iron chloride test gave a dark red color indicating a positive test for the
presence of
hydroxamic acid.
CA 02221703 2006-O1-31
WO 96138220 3~ PGTlUS96108143
EXAMPLE I (polymer I)
A hydroxamic acid containing water-soluble polymer of the structure:
+~~
Nx o
I
«-c-~urto~
was prepared from the ring opening of polyvinylpyrrolidone with hydroxamic
acid to give polyvinylamine-N(pentanoic hydroxamic acid) (PVA-PHA).
Polyvinylpyrrolidone (1.0 g, MW 40,000, Aldrich), sodium hydroxide (40 mL of
1.0
M), and hydroxylamine hydrochloride (2.71 g) were mixed together and heated to
90°C. A pH 12 was maintained by small additions of sodium hydroxide if
necessary.
The solution was heated for two days, cooled and dialyzed through a 20,000
MWCO
membrane. Water was removed from the polymer solution under vacuum to give a
clear solid material upon drying in an oven at 600C (referred to hereinafter
as polymer
I) which gave a positive ferric chloride test for hydroxamic acid
(hydroxylamine does
not give a positive ferric chloride test).
EXAMPLE J (polymer J)
A ester functionalized wpter-soluble polymer of the structure:
0
co~cn,
~ --i -~-N
a ~s~s O
O
was prepared as follows: Polyethyleneimine (1.00 g, purified as in Example A,
>30,000 MWCO) was dissolved in ethyl acrylate (9.21 g, 92 mmol)) and the
solution
stined at reflex for 3 hours. The excess ethyl acrylate was removed under
vacuum
keeping the temperature below 70° C to avoid its' polymerization. The
viscous
polymeric material was used in the next step without further purification
(referred to
hereinafter as polymer J).
CA 02221703 1997-11-19
WO 96138220 ' PGTlUS96l08143
38
EXAMPLE K (polymer K)
A hydroxamic acid functionalized water-soluble polymer of the structure:
HZCH2CNHOH - .
---fCH2CH2 N CH2CH2 N.~--
..
CH2CH2 ~ CH2CH21 ~ NHOH
HONHCCH2CH2 O
O
was prepared as follows. The polymer from Example I was treated with
potassium hydroxide (15.46 g, 0.28 moles) followed by a solution of
hydroxylamine
hydrochloride ( 12.79 g, 0.18 moles) in methanol ( 100 mL) maintaining a
temperature
below 20° C. The mixture was stirred for 1 hour then filtered. The
filtrate was added
to the crude PEI/ethyl acrylate adduct and stirred at room temperature for 14
hours.
The methanol was removed under reduced pressure and the residue dissolved in
water
(50 mL). The polymer was purified by diafiltration using a stirred cell with a
30,000
MWCO polysulfone membrane. After the collection of 6 volume equivalents (300
mL) of permeate, the water was removed from the retentate under reduced
pressure
and the material dried in a vacuum oven at 60° C overnight to give
92.22 g of the
polymer (referred to hereinafter as polymer K) as a light tan brittle solid
which was
very hygroscopic. IR (ATR): 1732 (C=O) cm 1.
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
39
EXAIyIPLE L (polymer L)
An aza crown ether containing water-soluble polymer of the structure:
(CH2CH2 ~ , CH2CHzNHr- ~O O
<\n
CH2CH2NHCH2 C N O
O O
was prepared on a polyethyleneimine as follows: N-Chloroacetyl-aza-18-crown-6
(0.56 g, 1.65 mmol), polyethyleneimine (0.29 g, prepurified as in example A,
>30,000
MWCO) and potassium carbonate were combined in acetonitrile and stirred at
reflux
for 16 hours. After cooling to room temperature, the solvent was removed under
reduced pressure leaving a brown oil. The residue was dissolved in water and
the
polymer purified by diafiltration. Evaporation of the water followed by drying
under
vacuum at 60°C gave 0.81 g of a tan solid (referred to hereinafter as
polymer L)
characterized by IR, 1H and 13C NMR.
EXAMPLE M (polymer M)
An all oxygen containing crown ether water-soluble polymer of the structure:
(CH2CH) ~
O
O
/O
O.
O
/O
composed of 15-crown-5 ether on polyvinylalcohol was prepared. 247 mg (4.94
mmole) of the polyvinylalcohol (88% hydrolyzed) in 10 mL of dried DMF was
warmed to 50-60o C to dissolve. The clear solution was than cooled to room
temperature and 341 mg (2.47 mmole) of K2C03 was added. The mixture was
stirred
for 30 min. Then, 0.67 g (0.33 mmole) of the 15-crown-5 in 2 mL of dried
dimethylformamide was added to the reaction mixture. The colorless mixture
turned
CA 02221703 1997-11-19 -
WO 96/38220 4~ PCT/US96/08143
to green-blue in 45 minutes and became light yellow in 2 hours. The yellow
mixture
was allowed to stir at 50-60o C for overnight. The reaction was quenched in
water,
the suspension was filtered and the polyvinylalcohol-crown ether was purified
by
ultrafiltration with a 30,000 MWCO cartridge and yielded 150 mg of polymer
(referred to hereinafter as polymer M) and characterized by IR, 1 H and 13C
NMR.
EXAMPLE N (polymer N)
A permethylated poly(vinylamine) water-soluble polymer of the structure:
(C~H )n
N (CH~3+ X
was prepared as follows: Poly(vinylamine) (10.0 g) was dissolved in 50 mL of
methanol and transferred to a four-neck round bottomed flask containing an
additional
SO mL of methanol. Phenolphthalein (10.0 mg) was added resulting in a light
pink
solution. Sodium methoxide (38.85 g, 0.72 mole) suspended in 450 mL of
methanol
and dimethylsulfate (90.69 g, 0.72 mole) dissolved in 100 mL of methanol were
added simultaneously by separate pressure equalizirtgadditio~,_gisat s,~c;~ a
rate
as to maintain a light pink color. The addition process was conducted under a
nitrogen atmosphere at room temperature. It was necessary to add additional
sodium
methoxide (3.0 g in 50 mL of methanol) to maintain the pink color throughout
the
dimethylsulfate addition. The total addition time was about 1.5 hours.
After the completed addition, the solution was brought to reflux and stirred
for
about 1.5 hours. After cooling to room temperature, the solution was
transferred to a
single neck flask and the solvent removed under reduced pressure leaving a
dark
yellow material. The material was re-dissolved in 450 mL of deionized water
and the
solution diafiltered using a 30,000 MWCO hollow-fiber cartridge. Five volume
equivalents or about 2.5 L of permeate was collected. For anion exchange from
sulfate to chloride, 50 g of sodium chloride in 150 mL of water was added and
the
solution allowed to stand overnight The solution was then diafiltered with 3 L
of
deionized water. The water from the retentate was removed under reduced
pressure
and the residue (referred to hereinafter as polymer N) dried under vacuum at
60° C
overnight to yield 19.58 g (69%) of an orange-brown crystalline solid. IR
(ICBr):
CA 02221703 1997-11-19
WO 96/38220 41 PGT/L1S96/08143
3437 (N-H), 2928, 1629 (C=O), 1481 cm 1. Elemental Analysis: C, 48.25%; H,
10.68%; N, 10.92%; Cl, 15.87%; S, <0.97%.
EXAMPLE O (polymer O)
A permethylated polyallylamine of the structure:
(CHzCH)-
~n
N~'~(CH~s X
was prepared. Polyallylamine (10.0 g, Aldrich) was dissolved in 100 mL of
methanol and transferred to a four-neck round bottomed flask containing an
additional
50 mL of methanol. Phenolphthalein (14.0 mg) was added to the solution. Sodium
methoxide (23.70 g, 0.44 mole) suspended in 400 mL of methanol and
dimethylsulfate (42.0 g, 0.33 mole) dissolved in 70 mL of methanol were added
simultaneously by separate pressure equalizing addition funnels at such a rate
as to
maintain a light pink color. The addition process was conducted under a
nitrogen
atmosphere at room temperature. It was necessary to add additional sodium
methoxide (3.0 g in 50 mL of methanol) to maintain the pink color throughout
the
dimethylsulfate addition. The total addition time was about 30 minutes.
After the completed addition, the solution was brought to reflux and stirred
for
about 1.5 hours. After cooling to room temperature, the solution was
transferred to a
single neck flask and the solvent removed under reduced pressure leaving an
opaque
pink material. The material was re-dissolved in 500 mL of deionized water and
the
solution diafiltered using a 30,000 MWCO hollow-fiber cartridge. Five volume
equivalents or about 2.5 L of permeate was collected. For anion exchange of
sulfate
for chloride, 50 g of sodium chloride in 150 mL of water was added and the
solution
allowed to stand overnight The solution was then diafiltered with 2.6 L of
deionized
water. The water from the retentate was removed under reduced pressure and the
residue dried under vacuum at 60° C overnight to yield 10.18 g (70%) of
a light
yellow crystalline solid (referred to hereinafter as polymer O). IR (KBr):
3437, 2929,
1686, 1485, 1251 cm 1. Elemental Analysis: C, 47.85%; H, 10.62%; N, 10.62%;
Cl.
11.78%; S, 1.13%.
EXAMPLE P (polymer P)
CA 02221703 1997-11-19 -,-
WO 96/38220 ' PGT/US96/08143
42
A guanidinium-containing PEI polymer of the following structure:
(CH2CH2 N CH2CH2N)~
CH2CH2 C NH2
H2+ X
H/
C NH2
' I
NH2+
was prepared as follows( where X- is sulfate): Polyethyleneimine (as
prepurified
in example A, >30,000 MWCO, 5.0 g, 116 mmole amine) and O-methylisourea-
hemisulfate (Jansen, 14.35 g, 116 mmol) were placed in a 125 mL flask and
dissolved
in 12 mL water with shaking. The solution was allowed to stand for 2 days, and
was
then placed in dialysis tubing (Spectra Por, 15,000 MWCO). The tubing with the
reaction mixture was placed in a 1 L jar containing deionized water, and the
water was
changed 5 times. The contents of the dialysis tubing was concentrated to a
white
foam by rotary evaporation, and then dried to a colorless glassy foam
(referred to
hereinafter as polymer P) under vacuum at 60oC overnight. Yield: 5.04 g.
Elemental
Analysis: C 33.88%, H 7.70%, N 26.69%, S 9.63%;
EXAMPLE O (polymer Q)
A permethylated PEI polymer of the structure:
Hs
(CH2CH2 ~ CHzCH2 ~ '~n
CH2 ~ Hz (CHa)2
N+(CH3)3 x
was prepared. Purified PEI (20.0 g as prepared as in example A, >30,000
MWCO) was dissolved in 200 mL of methanol and placed in a round bottom flask
outfitted with a condenser under argon. Dimethyl sulfate (120 g, 0.95 moles,
Eastman) dissolved in 110 mL methanol was added slowly from an addition
funnel.
After addition (about 3 hours) the reaction was brought to reflux while
potassium
carbonate (64.2 g, 0.046 moles, Janssen) was added slowly from a solids
addition
funnel (care should be taken to do a slow addition to prevent excess foaming).
The
CA 02221703 1997-11-19
. , -..~.
WO 96/38220 PCTlL1S96/08143
43 ,
solution was cooled, filtered, and the methanol removed under vacuum. The
solid
filter cake was dissolved in 600 mL of water and combined with the residue
from the
filtrate. The combined solution was purified by dialfiltration (30,000 MWCO)
using
water. The sulfate anion was exchanged for chloride by adding 120 gm sodium
chloride in 400 mL water and then stirnng for 48 hours. The solution was
concentrated and further diafiltered (30,000 MWCO) with water to 5 L volume
changes. The final solution was concentrated by ultrafiltration to 500 mL and
then
further concentrated and dried under vacuum to give a 21.6 g of an off white
glassy
polymer (referred to hereinafter as polymer Q). Elemental Analysis before
chloride
exchange: C 34.15%, H 8.07%, N 8.96%, S 15.56%. Potentiometric titration of
the
polymer gave a sharp strong-acid-base type titration curve indicating that all
the
amine sites were methylated. (If the curve was not sharp, it would indicate
that
methylation was incomplete).
EXAMPLE R (polymer R)
An amide containing water-soluble polymer of the structure:
~coN~
~2~2 ~ ~2~2 N
2 N~ ~N~
CONt-i~
was prepared as follows: Polyethyleneimine (2.00 g, prepared as in Example A,
>30,000 MWCO) was dissolved in methanol (20 ml) and brought to reflux.
Acrylamide (4.95 g, 70 mmol) and butylated hydroxytoluene (BHT, 200 ppm in
solution) was dissolved in methanol (20 ml) and added dropwise to the reaction
flask
over a 15 minute period. The solution was stirred at reflux for 24 hours.
After
cooling to room temperature, deionized water (400 ml) was added and the
polymer
purified by diafiltration using a 30,000 MWCO cartridge. The water was removed
under reduced pressure and the polymer dried in a vacuum oven at 60°C
to yield 4.5 g
of a clear glassy solid (referred to hereinafter as polymer R) and
characterized by IR.
1H and 13C NMR.
EXAMPLE S (polymer S)
CA 02221703 1997-11-19 .m..
WO 96/38220 ' 44 PCT/US96/08143
A permethylated polyvinylpyridine of the structure:
(CH2CH) ~
N
CH3+ X
was prepared as follows: To a solution of polyvinylpyridine (3 g as a 25%
solution in methanol, Reilly Industries) was added dropwise iodomethane (4.85
g,
0.03 mole) in 2 mL of methanol at room temperature. After addition was
complete,
the solution was stirred for about 2 hours giving a light green color. An
additional
amount of iodomethane (2 g) was added and allowed to stir for about 2 hours.
Deionized water (200 mL) was added to the reaction mixture and the solution
diafiltered with 1 L of permeate collected through a 30,000 MWCO membrane. The
water from the retentate was removed under reduced pressure and the residue
dried
under vacuum at 60° C overnight to.yield 4.82 g (68%) of a yellowish
green
crystalline solid (referred to hereinafter as polymer S). IR (KBr): 3437 (N-
H), 3028,
2930,1640 (C=O), 1156 cm 1. Elemental Analysis: C 40.74%, H 4.43%, N 6.22%, I
36.93%.
The iodide salt of polymer S was converted to the chloride salt by stirring
the
polymer overnight with sodium chloride (referred to hereinafter as polymer
Sa).
Elemental Analysis: C 52.65%, H 7.07%, N 8.27%, Cl 12.74%.
CA 02221703 1997-11-19
WO 96!38220 PCT/LTS96108143
EXAMPLE T (polymer Tl
A partially functionalized carboxylic acid containing water-soluble polymer of
the following structure:
(CH2CH CH2CH)
n
HNCH2COOH
NH2
was prepared on polyallylamine. A solution of sodium hydroxide (2.139 g) in
water (50 mL) was added dropwise over a period of 43 minutes to a solution of
polyallylamine (5.0 g, Aldrich) and chloroacetic acid (2.53 g) in water (60
mL)
keeping the temperature below SOoC. After the addition was complete, the
solution
was stirred at reflux for 3 hours. The solution was cooled to room
temperature. The
polymer was purified by diafiltration collecting five volume equivalents of
permeate
using hollow-fiber cartridges with a 30,000 MWCO. The bulk of the water was
removed from the retentate under reduced pressure. The residual material was
dried
in a vacuum oven at 60oC overnight to give 4.2g of a light tan solid (referred
to
hereinafter as polymer T). UV/VIS: lambda max = 296nm. IR(ATR): 1638 cm 1
(C~).
EXAMPLE U (polymer U)
A partially functionalized carboxylic acid containing water-soluble polymer of
the following structure:
(~H )~ .
HNCHzCOOH NH2
was prepared on polyvinylamine. A solution of sodium hydroxide (9.29 g) in
water (160 mL) was added dropwise over a period of 35 minutes to a solution of
polyvinylamine (10.0 g) and chloroacetic acid (10.97 g) in water (240 mL)
keeping
the temperature below SO°C. After the addition was complete, the
solution was
stirred at reflux for 3 hours. The solution was cooled to room temperature.
The pH of
the solution was 11.8 and adjusted using sodium hydroxide or hydrochloric
acid. The
solution started to precipitate between pH 7 and 8.5. The polymer was purified
by
diafiltration and rinsed with deionized water and adjusted to pH 11.3. Five
volume
equivalents of permeate was collected using hollow-fiber cartridges with a
30,000
MWCO. The bulk of the water was removed under reduced pressure. The residual
material was dried in a vacuum oven at 60°C overnight to give 12.42 g
of a light tan
CA 02221703 1997-11-19
WO 96/38220 ' PCT/US96/08143
46
brittle solid (referred to hereinafter as polymer U). UVlVIS: lambda max =
294nm.
IR (ATR): 1603 cm 1 (C=O).
EXAMPLE V (polymer V)
A water-soluble copolymer containing betadiphosphonic ester and amide groups
of the following structure:
(~)(~H2~2
CONH2 ~ (p)(p~H
2~2
was prepared by copolymerization. Acrylamide (664 mg, 9.35 mmole),
tetraethyl-ethenyldienebis(phosphonate) (S00 mg, 1.67 mmole), and ammonium
persulfate (21 mg, 1 %) as a polymerization initiator were dissolved in 20 mL
of
deionized water. The mixture was stirred vigorously at 65-700C for 48 hours
and the
solution remained clear throughout. The reaction was cooled to room
temperature and
diluted with deionized water to 250 mL. The polymer was purified by
diafiltration
using a 30,000 MWCO cartridge and collected 5 volume equivalents of permeate.
The retentate was concentrated and dried in a vacuum oven at 600C. A colorless
polymer was obtained (250 mg) (referred to hereinafter as polymer V).
Characterized
by IR, NMR, 31 P NMR (PPM) 26.02, 27.42.
EXAMPLE W (polymer W)
A water-soluble copolymer containing betadiphosphonic acid ester and amide
groups of the following structure:
Hoi (o)ocH2cH3
CHCH2 CH2C )~
CONH2 HOP(O)OCH2CH3
was prepared by copolymerization. Polymer V prepared as above (87 mg) was
dissolved in 10 mL of deionized water. Excess NaOH (24 mg) was added. The
clear
solution was stirred at room temperature overnight. The reaction was quenched
by
diluting with water to 200 mL, and purified by diafiltration using a 30,000
MWCO
membrane. The concentrate was dried under a vacuum at 60° C to give 80
mg of
CA 02221703 1997-11-19
WO 96/38220 PGT/US96/08143
47
light brown solid (referred to hereinafter as polymer W). The polymer was
characterized by IR, NMR, 31 P NMR (PPM) 27.2.
EXAMPLE X (polymer X )
A water-soluble copolymer containing betadiphosphonic diacid and amide groups
of the following structure:
HOI (0)0H
CHCH2 CH2C)~
I
HOP(O)OH
was prepared by copolymerization. The vinyl bisphosphonate (5.07 g, 16,9
mmole) was dissolved in trimethylbromosilane (20.7 g; ~ 135.2 mmole) under
argon.
The reaction mixture was stirred at room temperature overnight. Excess
trimethylbromosilane and other volatiles were removed under reduced pressure
and
the residual oil treated with 95% EtOH (15 mL). The mixture was stirred
overnight at
r3oria t°cmp°ciait~r°c. v'oiatii~ lWatGiiais wCr-c
rCiIloVCr agaiIl IlIIdCT Iiedlleed pressure to
give 3.0 g (90% yield) of pure vinyl bisphosphonic acid. Acrylamide (1.08g mg,
15.22 mmole), vinylbisphosphonic acid (500 mg, 2.72 mmole), and ammonium
persulfate (34 mg, 1%) as a polymerization initiator were dissolved in 20 mL
of
deionized water. The mixture was stirred vigorously at 50-SSOC for 40 hours
and the
solution remained clear throughout. The reaction was cooled to room
temperature and
diluted with deionized water to 50 mL. The polymer was purified by
diafiltration
using a 30,000 MWCO cartridge and collected 5 volume equivalents of permeate.
The retentate was concentrated and dried in a vacuum oven at 600C. A colorless
polymer was obtained (700 mg) (referred to hereinafter as polymer X).
Characterized
by IR, NMR, 31 P NMR (PPM).
CA 02221703 1997-11-19
WO 98/38220 ' PGTlUS96J08143
48
EXAMPLE Y (polymer Y)
A partially functionalized mercaptosuccinic acid containing water-soluble
polymer of the following structure:
(CH2CH2 N - CH2CH2NH)---
n
~2
N
H/ \C(O)CH2CH(SH)COOH
was prepared on polyethyleneimine. In a typical synthesis, 10.00g (233
milliequivalents of PEI, prepurified as in example A, >30,000 MWCO) was
dissolved
in 200 mL water and the solution purged with argon for twenty minutes. Solid S-
acetylmercaptosuccinic anhydride, 10.00 g (57.5 mmole), was added with
stirring.
After the solid disappeared, 10 g (94 mmole) of sodium carbonate was slowly
added
with care taken to ensure that the vigorous evolution of gas and resultant
foaming did
not cause an overflow. The solution was stirred overnight and then acidified
to pH 4
with concentrated nitric acid. After purging with argon for twenty minutes,
the
solution was brought to pH 7 with sodium hydroxide. The slightly cloudy
mixture
was filtered through a fine, glass frit. The product was purified by
diafiltration with at
least five times as much millipore water as the final solution volume.
Lyophilization
of the retentate yielded the product (referred to hereinafter as polymer Y).
Characterization: 1H and 13C NMR and IR.
Elemental analysis of 3 different batches
batch (1) C 42.57, H 7.19, N 12.85, S 9.17, S* 10.5
batch (2) C 42.78, H 7.09, N12.38, S 10.16, S* 8.4
batch (3) C 41.72, H 7.68, N 12.03, S 9.35, S* 8.2
S* Thiol sulfur content when analyzed by iodometric titration.
EXAMPLE Z (polymer Z)
A partially functionalized ethyl thiol containing water-soluble _pol_ymer of
the
following structure:
- (CHZCH2 - N - CH2CHZNH)-
n
CH2CH2
N
H/ CH2CHZSH
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
49
was prepared on polyethyleneimine. In a typical synthesis, 10.00g (233
milliequivalents of PEI prepared as in Example A, 30,000 MWCO) was dissolved
in
200 ml water and the pH was adjusted to 7 with concentrated HN03. The solution
was purged with argon for twenty minutes and 3.45 mL (57.5 mmole) of ethylene
sulfide was added with stirring. The biphasic mixture was stirred overnight
and the
slightly cloudy mixture was filtered through a fine, glass frit. The product
was
purified by diafiltration with at least five times as much millipore water as
the final
solution volume. Lyophilization of the retentate yielded 13.5 g of the product
as a
white powder (referred to hereinafter as polymer Z). Characterization:. 1 H
and 13 C
NMR and IR.
EXAMPLE AA (polymer AA)
A partially functionalized N-methylthiourea containing water-soluble polymer
of
the following structure:
(CH2CH2 ~ c~~NM
N
H/ 'C(S)NHCH3
was prepared on polyethyleneimine. In a typical synthesis, 11.20 g (260
milliequivalents of PEI, prepared as in Example A, >30,000 MWCO) was dissolved
in
200 ml of ethanol and the solution was purged with argon for twenty minutes.
Methylisothiocyanate was warmed to 35oC and 4.75 g (65.1 mmole) was mixed with
mL of ethanol. The isothiocyanate solution was added to the PEI at OoC and the
solution was stirred one hour at which time a gooey precipitate formed. The
solvent
was removed via rotary evaporation and the product redissolved in 100 mL of
water to
which 5.86 mL of concentrated HN03 was added. After stirring overnight, the
slightly cloudy mixture was filtered through a glass frit and the product was
purified
by diafiltration with at least five times as much millipore water as the final
solution
volume. Lyophilization of the retentate yielded 13.8 g of the product as a
white
powder (referred to hereinafter as polymer AA). Characterization-1H and 13C
NMR
and IR.
EXAMPLE BB (Polymer BB)
A phosphonic acid on a polyvinylamine backbone with the following structure:
CA 02221703 1997-11-19 -,
WO 96/38220' PCT/L1S96/08143
(CH2CH -CH2 ~ )n
N/H NH2
CH2P(O)(OH)2
was prepared. A solution of formaldehyde (9.42 mL) was added dropwise during
reflux over a period of 22 minutes to a solution of polyvinylamine (10 g) and
phosphorus acid (19.04 g). in 3N HCI. After the addition was complete the
solution
was stirred at reflux for an additional hour. The heat was removed and cooled
to room
temperature. The solution was titrated to pH 6.8 with NaOH. The polymer was
purified by diafiltration collecting five volume equivalents of permeate using
a
hollow-fiber cartridge with a 30,000 MWCO. The bulk of the water was removed
under reduced pressure. The residual material was dried in a vacuum oven at
60oC
overnight to give 18.21 g of a brittle yellow-orange solid (referred to
hereinafter as
polymer BB). UV/VIS: lambda max = 296nm. IR(ATR): 1628 cm-1 (C=O).
EXAMPLE 1
Binding Studies of the phosphoric acid containing water-soluble polymer of
example D (polymer D) at varying pH and nitrate concentration was conducted as
follows. These studies used polymer D with Amicon Centricon-10 (C-10)
microconcentrators having a 10,000 MWCO. A stock solution of polymer D (0.1
wt/vol%) was prepared with MilliporeTM water then prefiltered (Nalgene,
0.2p.).
Various concentrations of polymer D (0.001 %, 0.01 %, 0.05%, 0.1 %, 0.6
wt/vol%) and
NaN03 (0.1 M, 4.0 M) were used at pH ranges of 1 through 6. The working
solutions
were spiked with 2~'Am or Z38Pu and titrated with aqueous NaOH and dilute HN03
to
the desired pH values. The solutions were mixed for various times from two
hours to
overnight. The C-10 unit is comprised of two halves, a retentate (top) and
permeate
(bottom) portion, with the membrane filter attached to the retentate half.
Initial
weights of the retentate and permeate units were taken. Two milliliter samples
were
placed in the retentate half of the C-10 unit and centrifuged at 2200 rpm for
25 minutes
until one milliliter remained as the retentate and one milliliter as the
permeate. Final
weights were recorded for each unit. The ultrafiltration units were then
placed in
separate liquid scintillation vials with 13 mL of Ultima Flo AF (from Packard)
and
analyzed on an alpha counter (Beckman Instruments). Measuring the complete
units
(the two halves) with the sample gives 100% accountability as no samples were
transferred, thus, no activity losses from adhesion to the sides of the
apparatus. The
adsorption or binding capacity of the polymer for metal ions is expressed as
the
distribution coefficient (Kd) which is defined as: [total bound actinide/total
free
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
51
actinide] X [phase ratio]. The phase ratio is the sample volume/grams of
polymer
being used in the sample. The percent bound material is: [total bound metal
count]/[total count] X 100%. The results are reported in Table 1. It can be
seen that
both Pu(III)/(IV) and Am(III) bind well over the pH range 3 to 6 with Pu
having the
higher overall I~ values. One of the most interesting results from this study
is that the
Kd values are overall higher at the higher nitrate concentration.
Table 1. Study of Polymer D for pH and Ionic Strength for 2°'Am and
2'BPu.
0.1% wt/vol% at 0.1 M N03 0.1% wt/vol% at 4 M N03
of mer D of mer D
~H Avg. Log Kd Av~. Log Kd Avg. Log Kd d of
of of of Aver. Log~K
- 238 - 241 - _
241Am /Ret. -Pu /Ret. -Am /Ret 238
: Pu /Ret.
1 2.07(10.64%) 3.35(68.35%) 4.44(96.53%) 4.61(97.60%)
2 3.94(89.66%) 4.70(98.03%) 4.91 (98.79%) 4.69(98.01
%)
3 4.81(98.49%) 4.90(98.74%) 5.06(99.14%) 5.30(99.48%)
4 4.81(98.49%) 5.48(99.80%) 4.81(98.48%) 4.78(98.37%)
S 4.85(98.58%) 5.44(99.63%) 4.84(98.54%) 4.83(98.54%)
6 4.91(98.69%) 6.44(99.97%) 5.12(99.25%) 5.13(99.24%)
CA 02221703 1997-11-19 -'
WO 9/38220' PGT/US96/08143
52
EXAMPLE 2
Metal ion competition studies with iron(III) were conducted as follows. Since
iron is prevalent in the environment, competition studies against iron were
performed.
Working solutions containing various concentrations of Fe(NO~)3 (100 ppm, 500
ppm,
1000 ppm, 1500 ppm, 2000 ppm, and 2500 ppm) with 0.1 wt%/vol% polymer D and
1.0 M NaN03 at pH 4 were prepared and spiked with z°'Am. Using the same
centricon
units and procedures as in Example l, the results reported in Table 2 were
obtained.
The competition with Fe(N03)3 for binding sites on the polymer indicated that
1500
ppm Fe was needed before a definite decrease in the average Kd was observed.
Table 2. Competition study using 0.1 wt/vol% polymer D with Fe(N03)3 in 1.0 M
NaN03.
PPm FefNO~~ Log K~Am % Bound
0 4.79 98.21
100 4.78 98.35
500 4.76 98.28
1000 5.11 99.23
1500 3.31 66.90
2000 2.28 16.42
2500 2.51 24.81
3000 2.49 23.86
EXAMPLE 3
Comparison study of two chelating polymers, polymer D and polymer E, were
performed, at 0.1 wtlvol% by weight polymer concentration and NaNO, (0.1 M and
4.0 M) at pH range of 2 to 4. The working solutions were spiked with 24'Am,
titrated
to the appropriate pH, and mixed for 30 minutes. Two mL of the resulting
solutions
were centrifuged using the Centricon-10 unit until one mL passed the membrane.
The
top (retentate) and bottom (permeate) portions were placed in separate liquid
scintillation vials with Ultama Flo, shaken, and counted. The Kd values were
calculated and are reported in Table 3. Results from the comparison of polymer
E to
polymer D indicated that there was very little difference in the two polymer's
ability
to retain the actinide metals Pu and Am. The major difference is that there
was no
precipitation observed down to a pH value as low as 1 for polymer E whereas
polymer
D precipitated at pH 2.: Comparison of the two polymers at 0.1 M and 4.0 M
NaNO,
CA 02221703 2006-O1-31
WO 96!38220 PCTNS96l08143
53
indicated a slight increase in the log Kd values for polymer E at both high
and low
ionic strength relative to polymer D in most cases.
Table 3. Log Kd comparison of 0.1 wt/vol% polymer D and 0.1 wt/vol%
polymer E at 0.1 M and 4.0 M NaNO, at pH 2, 3, and 4 for ="Am retention.
p =0.1 s p = 4.0M NaNO,
M NaNO
pH_ o mer o er D ~H nolvmer polymer
EE D
2 3.45 4.32 2 4.36 4.59
3 4.79 4.70 3 4.99 4.56
4 4.82 4.78 4 4.74 4.54
EXAMPLE 4
Simulated urine used for this example was purchased from Carolina Biological
Supply Company, although the exact composition was proprietary. The simulated
urine can also be prepared according to Table C above.
Actinide concentration by ultrafiltration from simulated urine was conducted
as
follows: Simulated urine solutions were prepared containing 0.05% and 0.1%
wt/vol
polymer D. Concentrated nitric acid was added in the amount of 50 g per kg of
simulated urine to insure that spiked radionuclides remain in ionic form. The
solutions were spiked with 241 Am, pH was adjusted to 4, and then shaken for
30
minutes. Two mL samples were filtered with the C-10 units as described in
Example
1. The results are shown below in Table 4. It can be seen that even in the
presence of
all the other materials that polymer D effectively binds and concentrates
americium
for recovery from urine. The polymer D was compared with a polymer (PEI with
an
8-hydroxyquinoline complexant group) reported in the literature to bind
actinides
from aqueous solutions. This can then be used for an analytical method_ to
analyze
actinide metal ions in urine or potentially other bodily fluids.
CA 02221703 1997-11-19
WO 96/38220 ' PGT/US96/08143
54
Table 4. Ultrafiltration Using Simulated Urine Spiked With ~'"Am at pH 4.
Polymer, wt/vol% Total Bound Total Free% bound
c m c m
0.05% polymer D, 162835 4676 97%
0.10% polymer D 154956 4480 97%
0.05% 8HQ polymer* 56211 60547 48%
0.10 % 8HQ polymer* 54803 29540 65%
aynu esizea accoramg to the procedure from Burckhalter et al.,
J. Org. Chem., vol. 26, p. 4078 ( 1961 ).
EXAMPLE 5
Actinide concentration by ultrafiltration of simulated brine waters was
conducted
as follows: A simulated brine solution of Table B was prepared containing 0.05
wt/vol% and 0.1 % wt/vol polymer D. The solutions were spiked with Am(III),
plutonium(III/IV), uranium(VI), thorium(IV) or neptunium(IV). The pH was
adjusted
as necessary, and then the solutions were shaken for 30 minutes. Two mL
samples
were filtered with the C-10 units as described in Example 1. The two halves of
the C-
unit were placed in different scintillation vials with Ultima Flo
scintillation fluid
and counted. The results are shown below in Table 5.
Table 5. Ultrafiltration of simulated brine with 0.1 wt.vol% polymer D at pH
4.
Actinide Total BoundTotal % Bound at pH
free 4
241-Am 6463 ' 114 98%
238-Pu 329 58 85%
232-Th 166 353 32%
238-U 2754 12170 18%
238-U 6564 111 96% (at pH 6)
239-Np 4231 803 84%
EXAMPLE 6
Actinide concentration by ultrafiltration of simulated actinide-containing
waste
waters was conducted as follows: A series of ultrafiltration experiments were
performed with simulated TA-50 waste waters as shown in Table D spiked with
~"Am.
The ultrafiltration experiments used stirred cell apparatus (Amicon) with a
10,000 or
30,000 MWCO cellulose acetatelpolypropylene backed membranes, pressurized with
nitrogen to 75 psi. The spiked polymer solution was prepared with simulated
waste
CA 02221703 1997-11-19
WO 96/38220 PGT/LTS96/08143
water at 0.05 wt/vol% to 0.1 % wt/vol% polymer D. A measured volume of
solution
was added to the cell reservoir and stirred constantly during the filtration.
Equal
volumes of the retentate and permeate were analyzed for z4'Am by gamma
counting
(Packard Minaxi auto-gamma counter, Series 5000).
The permeate, retentate (if present), and membrane were analyzed for actinide
content as follows: One milliliter aliquots and the folded membrane filter
were placed
in Roehen tubes and analyzed by the gamma counter. Liquid samples were
prepared
for alpha liquid scintillation counting by taking 2 mL aliquots, adding 16 mL
of
Optifluor liquid scintillation fluid (Packard), and shaking the solution
vigorously. The
membrane filter was prepared for alpha liquid scintillation counting by
dissolving the
membrane in 1 mL of concentrated H2S04 (18%-24%, Baker) and diluting with 10 .
mL of distilled water to produce 10 mL sulfuric acid solutions. A 2 mL aliquot
of this
solution was mixed with 16 mL of Optifluor and analyzed for Am. A retention
percentage was calculated as 100% X [(retentate count in 1 mL X retentate
volume) +
(total membrane count)]/(starting material count in 1 mL X starting volume).
Accountability was determined by summing all the components (membrane,
retentate
and permeate) and comparing it to the starting material.
Table 6. Ultrafiltration using simulated waste water with 0.05 wt/vol% polymer
D, the polymer spiked with Z°'Am at pH 4.
Sample InitialVolumeInitialretentatePermeate Permeate % Bound/
cprn c m col ml c m Accountability
1 100 10,250965,231 95.5 350 94.2 /(97.4)
2 109 169 17,123 106 5.5 93.0 /(96.1)
241 ~ activity was determined by gamma counting.
The results shown in Table 6 (sample 1 ) indicate good americium recovery in
the
retentate and high accountability, demonstrating the selectivity of this
chelating
polymer for Am(III). The data for simulated waste waters (where exact
concentrations
and metal ion comp g itions are known) show that even at actinide metal-ion
concentration of 10 M the polymer is selective for Am over calcium, magnesium,
potassium, and sodium which are present in much higher concentrations relative
to Am
(Table D). There is also selectivity for Am (III) over divalent transition
metal ions
such as copper and nickel which are present in higher concentrations than
Am(III).
Iron at a concentration 1000 times higher than the Am(III) indicated no
interference at
these tracer levels. In addition to the actinide competition with other metal
ions for
CA 02221703 1997-11-19 --._
WO 9G!38220 ' PGT/L1S96/08143
56
polymer binding sites, the polymer was competing with high concentrations of
anions
(phosphates and nitrates) for actinide binding.
EXAMPLE 7
A study of PEI-dimethylacetylpyrazalone (polymer F) was conducted as follows:
A systematic study of PEI-DMAP to determine the optimum working concentration
involved surveying polymer F binding at different polymer concentrations (0.05
wdvol%, 0.1 wt/vol%, 0.6 wt/vol%) and ionic strengths (NaN03 at 0.1 M and 4.0
M)
over a pH range of 2 to 12. The prepared solutions were spiked with
2°'Am and
treated as described above in Example 1. Polymer F had good solubility
properties
over the whole pH range studied.:, There was no precipitate seen at low pH
values.
The polymer filtration at 0.1 wdvol% and 0.6 wbvol% were well behaved, the
higher
~eoncentrations took much longer to filter and did not have as good binding
--capabilities as at 0.05 wt/wt% of the polymer. Table 7 shows the optimum
conditions
for this polymer are at 0.05 wdvol% concentration and pH 7.
CA 02221703 1997-11-19
WO 96/38220 PCT/US96I08143
57
Table 7. Log Kd of polymer F at 0.1 M NaN03 and varying concentrations and
pH.
Log Kd
poll poll pol,
pH 0.05 wt/vol% 0.1 wt/vol% 0.6 wt/vol%
2 2.05 2.11 1.49
3 2.76 2.66 2.06
4 3.77 3.66 3.12
4.38 4.23 3.42
6 4.45 4.37 3.37
7 4.62 4.32 3.88
8 4.43 4.41 3.83
9 4.38 4.31 3.81
4.46 3.92 3.70
11 4.28 4.17 3.72
12 4.43 4.31 3.66
EXAMPLE 8
A study of PEI-methylphenylacetylpyrazalone (polymer G) was conducted as
follows: A survey study of polymer G to determine the range of working
concentration involved surveying polymer G binding at two pH values 2 and 6.
The
prepared solutions were spiked with Z"Am, adjusted to the appropriate pH with
nitric
acid, and filtered through a HarpT"' (Supelco) hollow fiber having a 10,000
MWCO.
Polymer G had poor solubility properties precipitating above pH 3.5. The
results are
summarized in Table 8.
EXAMPLE 9
A study of polyhydroxamic acid (polymer I) was as follows: A survey study of
polymer I to determine the range of working concentration involved surveying
poly 24 i I binding at three pH values 2, 6. and 8. The prepared solution were
spiked
with Am, adjusted to the appropriate pH with nitric acid, and filtered through
a
HarpT"' (Supelco) hollow fiber having a 10,000 MWCO. Polymer I had reasonable
solubility over the full working range. The results are summarized in Table 8.
CA 02221703 1997-11-19
WO 96138220' PCT/US96/08143
58
Table 8. Survey of binding properties of several water-soluble polymers for
241Am.
Polymer % Bound % Bound % Bound
at pH .1 at pH 6 at pH 8
polymer G c2% 83%* _______
8-HQ'H* * ~% 97% _______
8-HQ-Me* * c2% 19% _______
polymer B <2% g4% ______
polymer I <2% c2% 99%
Ymymer was insoluble at this pH.
**Prepared according to the procedure from Bankovkis et al.,
-Khim. Getero. Soed., vol. 11, p. 1501 (1979), and purified by dialysis z
20,000
MWCO.
EXAMPLE 10
Separation of trivalent actinides (Am-241 ) from trivalent lanthanides (Eu-
154)
using polymer B in a liquid-liquid extraction system: A 0.1 M solution of di-2-
ethylhexylphosphoric acid (HDEHP) was prepared in diisopropylbenzene (DIPB)
and
pre-equilibrated with a pH 3 nitric acid solution. A solution between 0 and 2
wt/vol%
of polymer B was mixed that contained lactic acid between 0 and 1.5 M, an
ionic
strength of between 0.1 and 1.0 (nitrate, chloride, or perchlorate), a pH
between 2 and
4, buffered to 0.01 M with sulfanilic acid, and spiked with Eu-154 and Am-241.
Equal volumes of the organic phase (2 mL) was contacted with equal volumes of
the
aqueous phase by shaking for 30 minutes in duplicate. The phases were
disengaged
by centrifugation and one mL aliquots of each phase were gamma counted using a
sodium iodide detector to determine the amount of each tracer metal ion in the
respective phases. Comparison experiments without polymer, at different pH
values
and with diethylenetriaminepexitaacetic acid (DTPA) were tested. The results
are
shown in Table 9. It can be seen that good separation is realized with the Eu
being
preferentially extracted over Am in the presence of polymer B under certain
conditions. Polymer B had good solubility in the regions studied. The results
are
comparable to using DPTA, a single ligand, but the solubility of the polymer
is
greatly improved over the single ligand, and the Am can be concentrated and
recovered by ultrafiltration from the aqueous phase. It can be seen that the
amounts of
polymer, lactic acid and counter ion are important in optimizing the
separation factor
(SF) which is defined as the distribution of Eu/distribution of Am (DEu/DAm)-
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
59
Table 9. Extraction results under variable conditions for Eu/Am separation
using water-soluble polymer B.
Condition S~Eu~Am~
0.5 M HDEHP/0.1 M NaN03/no 0.60
polymer/pH 2.5
0.5 M HDEHP/0.1 M NaN03/no 0.85
polymer/pH 3.2
0.5 M HDEHP/0.1 M NaNO~/no 1.0
polymer/pH 3.5
0.1 M HDEHP/1.0 M LiC104/2 2.1
wt/vol%
polymer/pH 4.4
0.1 M HDEHP/0.1 M LiC 3.6
10,/2 wt/vol%
_
polymer/pH 4.2
0.1 M HDE~P/O.I M LiCI/0.2 2.9
wt/vol%
polymer/pH 3.0
0.1 M HDEHP/0.1 M LiCI/0.5 4.1
wt/vol%
polymer/pH 3.0
0.1 M HDEHP/0.1 M LiCI/2 wt/vol%11.7
polymer/pH 3.1
0.1 M HDEHP/2 wt/vol% polymer/1.527.5
M lactic acid/pH 3.1
O.I M HDEHP/0.1 M NaN03/2% 23.1
polymer/1.5 M lactic acid/pH
2.4
0.2 M HDEHP/0.1 M NaN03/2 8.I
wt/vol%
polymer/1.0 M lactic acid/pH
2.9
0.1 M HDEHP/0.05 M DTPA/I.5 10.2 (Dp~/DEu)
M
lactic acid/pH 3.4
EXAMPLE 11
Using polymers A, C, and E, tests were performed to determine the selective
recovery of metal ions used in the electroplating industry from solutions that
have
chloride, sulfate and nitrate counter ions. Individual solutions containing
0.1 M
sulfate, 0.1 M nitrate and 0.1 M chloride with 0.1 wt/vol% of the three
polymers (A,
C, or E) were prepared at a pH range of 2 to 7. All solutions contained
copper(II),
nickel(II), aluminum(III), iron(III), chromium(VI), zinc(II), lead(II), and
cadmium(II)
ions at the 10 to 20 ppm range (low end concentration range expected in
electroplating
rinse waters or other types of waste water or process waters). Ten milliliters
of the
resulting solutions were centrifuged using the Centriprep-10 unit (Amicon)
having a
MWCO of 10,000 until eight mL passed the membrane. The top (retentate) and
CA 02221703 1997-11-19 - .
WO 96A38220 ' PCT/US96/08143
bottom (permeate) portions were analyzed by ICP-AEC for metal ion content. The
results are summarized below in Tables 10(a) -10(h).
i ame tua. Metals concentrations in the permeate with polymer A in 0.1 M
chloride. - '
run pH ppm ppm ppm ppm ppm ppm ppm ppm
no. Cu Ni Al Fe Cr Zn Pb Cd
0 2.00 5.22 14.33 13.03 11.50 11.68 12.73 10.58 12.55
1 2.87 0.10 14.25 12.58 10.93 12.85 12.85 11.48 12
68
2 4.03 0.024 2.89 11.63 2.32 7.89 10.94 12.11 .
10.29
3 4.78 0.024 0.04 2.19 0.44 0.63 0.63 9.60 0.20
4 5.94 0.67 0.32 0.31 0.31 0.04 0.14 1.34 0.06
Table 10b. Metals concentrations in the permeate with polymer C in 0.1 M
chloride.
run pH ppm ppm ppm ppm ppm ppm ppm ppm
no. 2.02 Cu Ni Al Fe Cr Zn Pb Cd
0 4.53 4.80 10.94 4.30 10.94 6.75 7.94 9
37
1 2.9I 0.20 0.51 8.11 0.33 11.08 0.37 0.48 .
0
96
2 3.74 0.05 0.38 3.38 0.09 9.03 0.10 0.30 .
0
30
3 4.75 0.77 1.19 0.97 0.76 5.16 0.88 0.77 .
0
84
4 5.76 0.03 0.31 0.06 0.06 0.38 0.08 0.30 .
0
30
5 6.53 0.03 0.30 0.05 0.06 0.05 0.06 0.16 .
0.04
'fable 10c. Metals concentrations in the permeate with polymer E in 0.1 M
chloride. .-
run pH ppm ppm ppm ppm ppm pprri ppm ppm
no. 2.05 Cu Ni Al Fe Cr Zn Pb Cd
0 0.98 12.89 0.55 0.41 11.46 11.78 10.63 12.07
1 2.94 0.80 7.34 0.08 0.03 11.36 7.51 7.45 9.97
2 3.93 0.23 0.97 0.23 0.24 7.51 0.91 1.17 1.79
3 4.67 0.23 0.58 0.24 0.20 2.89 0.62 0.11 0.39
4 5.54 0.87 0.58 1.94 5.70 0.30 0.10 1.12 0.30
5 6.97 0.15 0.33 0.27 1.01 0.15 0.10 1.00 0.30
CA 02221703 1997-11-19
WO 96/38220 PCT/US96I08143
61
Table 10d. Metals concentrations in the permeate with polymer C in O.I M
sulfate.
run pH ppm ppm ppm ppm ppm ppm ppm ppm
no. Cu Ni Al Fe Cr Zn Pb Cd
0 2.18 0.06 0.11 8.61 0.26 8.25 3.28 6.75 8.11
1 2.92 0.07 0.05 5.13 0.21 8.47 0.37 1.81 2.13
2 3.86 0.04 0.05 1.57 0.10 8.19 0.10 0.60 0.30
3 4.93 0.03 0.10 0.18 0.10 3.38 0.10 0.60 0.30
4 6.02 0.17 0.29 0.22 0.22 0.27 0.20 0.60 0.30
~~
Table 10e. Metals concentrations in the permeate with polymer E in 0.1 M
sulfate.
run pH ppm ppm ppm ppm ppm ppm ppm
no Cu Ni Al Fe Zn Pb Cd
0 3.950.08 0.48 0.10 0.10 0.76 0.60 0.90
1 5.110.09 0.07 0.10 0.10 0.17 0.60 0.30
2 6.090.07 0.10 0.10 0.10 0.09 0.60 0.30
3 7.060.07 0.06 0.10 0.10 0.10 0.60 0.30
Table 10f. Metals concentrations in the permeate with polymer A in 0.1 M
nitrate.
run pH ppm ppm ppm ppm ppm ppm ppm ppm
no. Cu Ni Al Fe Cr Zn Pb Cd
0 2.04 3.96 5.19 4.99 3.75 3.71 4.76 2.95 4.31
1 3.05 0.15 5.16 4.88 2.83 3.47 5.39 2.97 4.28
2 4.02 0.052 3.72 4.72 0.44 2.67 5.34 2.80 4.36
3 4.97 0.021 0.035 1.86 0.049 1.73 2.57 2.54 2.70
4 6.21 0.034 0.02 0.01 0.01 1.15 0.088 0.33 0.042
6.86 0.047 0.02 0.01 0.01 1.49 0.081 0.03 0.045
Table 10g. Metals concentrations in the permeate with polymer C in O.I M
chloride.
run pH ppm ppm ppm ppm ppm ppm ppm ppm
no. Cu Ni Al Fe Cr Zn Pb Cd
0 1.91 0.223 0.319 12.66 0.508 2.513 4.907 2.875 8.702
1 2.89 0.190 0.281 6.22 0.358 2.314 0.449 0.40 1.52
2 3.71 0.158 0.276 1.01 0.214 1.881 0.211 0.40 0.244
3 4.97 0.138 0.207 0.442 0.308 1.667 0.185 0.40 0.22
4 5.99 0.117 0.185 0.316 0.343 1.853 0.154 0.40 0.143
5 6.94 0.086 0.124 0.226 0.231 2.272 0.124 0.40 0.111
CA 02221703 1997-11-19 - .
WO 9fs/38220 "
PGT/US96/08143
62
Table 10h. Metals concentrations in the permeate with polymer E in 0.1 M
chloride.
run pH pm Cu ppm ppm ppm ppm Cr ppm ppm Pb ppm _
no. 2.05 0 Ni Al Fe Zn Cd
0 405 4 0
991
. . .071 0.056 0.360 4.624 3.354 4.249
1 3.10 0.075 3 0
111 032
. . 0.034 0.271 3.211 2.166 3.177
2
4.06 0.058 0.22 0.027 0.036 0.176 0.391 0
074 0
401
3 5.21 0.051 0.041 0.028 0.010 0.258 0.064 .
.
0
030 0
031
4 6.34 0.043 0.02 0.01 0.031 0.449 0.078 .
.
0
030 0
015
7.06 0.045 0.02 0.01 0.020 2.128 0.046 .
.
0.030 0.010
It can be observed that the binding properties of the three polymers are quite
different and the binding properties of each polymer varied depending upon the
counter ion ( i. e., sulfate, chloride or nitrate) in the solution. In sulfate
solution the
polymers experienced solubility problems with polymer A being insoluble at <
pH 5,
polymer E insoluble at < pH 3 and polymer C insoluble at < pH 2.5. The other
polymers were completely soluble at all conditions studied. Thus, this data
demonstrates the importance of knowing the counter ions that exist in the
waste
streams (along with the anion concentration) to be able to choose the proper
polymer
or polymers for the desired separation. It demonstrates that certain polymers
remove
metal ions from solution to a lower level than others under the same pH
conditions.
The data demonstrates that where the metal ions might be bound under certain
anion
conditions, that they may be selectively released using different anions as
eluents.
The data demonstrates that if one is treating waste streams that have higher
levels of
metal ions to be recovered and lower levels of trace impurity metals that must
lie
removed from a waste stream but separated from the major metals, that mixtures
or
formulations of polymers can be developed to address specific waste streams.
EXAMPLE 12
Recovery of Zn and Ni from electroplating rinse baths containing borate,
ammonium and chloride ions (single polymer systems) was conducted as follows.
Retention studies were performed on dilute electroplating bath solutions for
evaluating the individual polymer's effectiveness in retaining the
electroplating metals
in the presence of other bath constituents. The composition of the bath used
was
made according to Table E as the Zn/Ni alloy bath.
Surfactant was left out of this surrogate solution since it would be removed
by
carbon treatment prior to ultrafiltration. Note that when polymer filtration
is preceded
by surfactant and oils removal using carbon or polymers such as XAD-4 (from
Rohm
and Haas), and followed by ion exchange treatment to allow for removal of
additional
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
63
inorganic ions that are not selectively removed by the polymer filtration
process, clean
water which can be used for recycle can be obtained.
The bath was diluted 1:100 to simulate rinse waters resulting in Ni and Zn
metal
ion concentrations in the range of I80 ppm and 90 ppm, respectively. The
concentrations of the other species in solution were diluted in the same
proportions.
The general procedure for retention studies involved the addition of an excess
of
purified polymer (polymer A or polymer B) to the dilute rinse waters. The
solutions
were adjusted to the desired pH (1-7) and ultrafiltered through a 10,000 MWCO
polysulfone membrane using a stirred cell. The volumes of retentate and
permeate
were measured and both analyzed for Ni and Zn by ICP-AES. The results are
shown
in Table 11.
Table 11. Percent metal retained for polymer A and polymer B from a Zn/Ni
electroplating rinse bath.
~H Ni- Zn- Ni- Zn-
polymer A polymer A polymer B polymer B
1.0 63.7 55.5 60.0 66.9
2.0 61.8 57.8 79.6 42.9
3.0 59.6 54.9 97.9 92.9
4.0 91.7 95.0 100 95.2
5.0 97.9 100 100 96.5
6.0 96.6 100 100 97.2
7.0 97.8 100 100 89.3
Polymer A gave good retention for both metals at pH 5 and above indicating
that
polymer A could readily compete with ammonia in the electroplating solution.
Below
pH 5, polymer A began to release the metals and by pH 3, most metals were free
in
solution. Within experimental error, there were no differences in the
selectivity of
polymer A for one metal over the other and therefore no possibility of
selective
stripping. A similar trend in Ni/Zn retention was observed for polymer B.
However,
there was a shift in the pH at which the metal ions were released. This shift
towards a
lower pH was a result of the higher stability constants for the polymer B-
metal ion
complexes over those of the polymer A-metal ion complexes. Polymer B formed a
slightly stronger complex with Ni over Zn as shown with the higher retention's
for Ni
at pH 3 and pH 2.
Regeneration studies were run to investigate the ability of the polymers to go
through
a full cycle of metal ion retention/concentration, metal-ion recovery by
diafiltration,
and polymer reloading using the electroplating rinse waters. In a general
procedure.
CA 02221703 1997-11-19
WO 9C/38220' PGT/US96/08143
64
dilute electroplating bath solutions (50 mL) were treated with an excess of
polymer at
pH 6. These solutions were concentrated a 10 mL using a stirred cell with a
10,000
MWCO membrane. The metal ions were released from the polymer by adjusting the
pH and collected by diafiltering. This procedure was repeated an additional
two times _
after raising the pH of the polymer retentate back to 6. For polymer A
regeneration
studies, the initial concentrations of Ni and Zn the solution at pH 6 were 45
ppm and
24 ppm, respectively as determined by ICP-AES. During the first concentration
to 10
mL, retention of the Ni and Zn gave no detectable metals (detection limit 0.01
ppm) in
the permeate. After adjustment of the pH to 2, the solution was diafiltered
with six
volume equivalents collected. The percent metal ion (Ni, Zn) retained after
each
volume equivalent was slightly above the theoretical values calculated for
retention
coefficient (a), indicating some weak polymer/metal ion interactions were
still were
Melt even at pH 2.
The second and third regeneration results were similar to that of the first.
In both
concentration steps no metals were detected in the permeate (detection limit
<0.01
ppm), indicating excellent retention. The two diafiltrations followed a
similar trend
with all curves falling slightly above the theoretical values for a=0. The
conclusions
of the study indicate that polymer A can successfully retain electroplating
bath metals
from dilute solutions, concentrate, strip of metal and recycle without the
loss of
performance. Experiments with polymer B gave similar results but the stripping
pH
was 0.35 instead of pH 2.
While the above experiments were performed using the small stirred cells, the
following experiment processed ~5.5 L of simulated dilute electroplating bath
rinse
water solution using a hollow-fiber ultrafiltration cartridge to determine the
effectiveness of polymer A in retaining, concentrating, and recovering the
plating bath
metals from the bulk of the solution. The initial concentrations of Ni and Zn
in the
solution as determined by ICP-MS was 164.5 ppm and 91.4 ppm, respectively. The
boron concentration from boric acid was 31.7 ppm. The pH of the solution was
adjusted to 6.3 by the addition of concentrated hydrochloric acid.
Conditions for the process involved using a 10,000 MWCO hollow-fiber
cartridge (1.5 sq. ft, 0.14 sq m). Recirculation rates of ~4 L/min. were
maintained
using a peristaltic pump. The operating back pressure was 15 psig (pure water
flux at
this back pressure was 147 mL/min.). The initial concentration of polymer A
was ,
0.12 wt/vol%. Based on previous loading capacity results, quantitative Ni/Zn
metal
ion retention would take-up approximately 70% of the polymer's capacity (based
on .
0.25 g metal/g polymer). The final volume of the solution after the
concentration step
was 350 mL or about 15 fold concentration. Permeate rates were taken every
1000
mL, and indicated that after the first 3000 mL of permeate collected, their
was no
CA 02221703 1997-11-19
WO 96/38220 6~ PCT/US96/08143
decrease in the flux rates which were 65% of that of pure water. This is
despite an
increase in polymer concentration from 0.12% to 0.21 wt/vol%. Only after 4000
mL
of permeate was collected did the flux rates begin to drop. During this volume
reduction, the average concentration of metal ions in the permeate was -rl ppm
for Ni
and 2.3 ppm for Zn indicating good retention by the polymer.
After the solution was concentrated by a factor of 15, the metals were
released
from the polymer by the addition of concentrated hydrochloric acid to a final
pH of
2Ø At this point, the initial permeate from the diafiltration process was
calculated to
show a metal ion concentration approximately ten times that of the initial
metal ions
concentrations (164.5 ppm Ni, 91.4 ppm Zn). The results from the ICP-MS were
in
close agreement showing 1617 ppm Ni and 1009 ppm Zn in the first volume .
equivalent of permeate. The concentrations of Ni and Zn in successive permeate
fractions follow the expected decrease as seen in previous experiments.
Whether there was any interaction between the boric acid and the polymer was
then investigated. With the possibility of hydrogen bonding between the two
species,
boric acid might also be concentrated to a certain degree. The initial
concentration of
boron in the solution before volume reduction was 31.7 ppm. The concentration
in
the permeate during the volume reduction was ~34 ppm and the concentration of
boron during the diafiltration process after acidification was 31.5 ppm in the
first
permeate fi~action with each subsequent volume equivalent showing a decrease
in
concentration. This is strong evidence that there was little, if any,
interaction between
the polymer and the boric acid and therefore boric acid should not interfere
with the
polymer/metal ion binding.
EXAMPLE 13
Recovery of zinc and nickel from electroplating rinse baths containing copper
and iron metal ion impurities plus borate, ammonium and chloride ions (two
polymer
system): From the previous experiments it was evident that in waste streams
containing only nickel and/or zinc, a single polymer system can be used for
metal ion
recovery in the presence of ammonia or borate. However, in the presence of
other
metal ion impurities such as those described in Example 1 l, polymer A (PEI)
alone
would not show the needed selectivity for the recovery of the nickel and/or
zinc. At a
higher pH (6 - 7), PEI is selective for those metals described in Example 11
over
sodium, potassium, lithium, calcium, and magnesium (alkaline and alkaline
earth
metals of group Ia, and IIa). but the selective separation of zinc and/or
nickel from
iron, cadmium, lead, aluminum and chromium and copper could not be
accomplished
by stripping, since all these metals gave similar pH retention profiles with
PEI. The
addition of a second polymer, such as polymer C in appropriate amounts, which
has a
CA 02221703 1997-11-19 '"'
WO 96138220 ' 66 PCT/US96/08143
greater affinity for the trace metal impurities such as copper and iron would
act as a
scavenger for these metal impurities. Thus, by using polymer A for the primary
binding of nickel and zinc and polymer C for the scavenging of metal
impurities, the
performance of the process can be improved.
By mixing polymer A with Polymer C (which has a different binding profile than
polymer A) in such a proportion that polymer C will act as a scavenger for the
trace
metals of copper and iron while polymer A is the major binder of the metals
like zinc
and nickel, improved performance and selectivity for the process should be
possible.
A test treatment of 40 gallons of electroplating rinse water was conducted. A
solution for testing was made from the Zn/Ni electroplating bath formulation
from
Table E above. The electroplating bath solution was diluted approximately
1:100 to
aimulate the rinse waters. In addition to the nickel and zinc, low
concentrations (1-4
~ppm) of five other metals were introduced to the 40 gallons to simulate
possible
impurities found in the plating solutions. These five metals ions were
aluminum(III),
lead(II), copper(II), cadmium(II), chromium(III), and iron(III). The polymer
mixture
consisted of 90% polymer A and 10% polymer C. This polymer mixture had an
initial concentration of 0.15 wt/vol%. Based on results obtained from previous
loading capacity studies, calculations indicated the retention of all metal
ions in
solution gave 80% loading of the polymers. The analysis of the initial feed
solution to
be processed was performed by ICP-MS with the following results shown in Table
12:
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
67
Table I2. Concentration of metal ion species in the initial feed solution of a
Ni/Zn rinse bath.
Metal ppm Metal ppm
B 19.90 Zn 69.8
Cr 1.02 A1 2.11
Fe 3.77 Cu 2.35
Pb 2.66 Cd 4.03
Upon the addition of the polymer to the metal ion solution, various colors
were
evident indicating the formation of polymer-metal complexes. Once the polymer
was
completely added with thorough stirring, a dark purple solution, indicative of
the PEI-
nickel complex, could be seen. During the concentration stage of the
experiment
(using a hollow fiber ultrafiltration cartridge with a 10,000 MWCO), the
expected
decrease in the permeate flow rate as well as the total volume of permeate
collected as
a function of time was observed. The total time to process the forty plus
gallons of
the solution was approximately one hour.
The permeate collected during the concentration stage was analyzed for metal
ion
content and gave a nickel concentration of 1.94 ppm and a zinc concentration
of 1.36
ppm. While these concentrations were below discharge levels, they were greater
than
the goal of <1 ppm for both of the metals (it has since been found that when
the
process system was at pH 6.5 this was the permeate concentrations, if the
process was
run at pH 7 the permeate was <0.01 ppm). The analysis for all impurity metals
added
to the solution were found to be less than 0.05 ppm in the permeate .
Once the-solution was concentrated to approximately 1.5 gallons, the pH of the
solution was lowered to 3.5 followed by diafiltration to recover the metal
ions. Five
volume equivalents were collected with each fraction being analyzed for metal
ion
concentration (Table 13). It is clear from the results that pH 3.5 is not the
optimum
pH for nickel and zinc metal ion release. The polymer solution appears to have
a
greater retention for nickel than for zinc, however after five volume
equivalents,
significant amounts of nickel and zinc were still present in retentate.
CA 02221703 1997-11-19 '
WO 96r38220 ' PCT/US96/08143
68
~ ame m. IvvGn concentrations remaining in various samples or fractions.
Ni m) Zn m
Permeate from Concentration1.94 1.4
Volume Equivalent 1-pH 3.5 533 699
Volume Equivalent 2-pH 3.5 422 376
Volume Equivalent 3-pH 3.5 398 234
Volume equivalent 4-pH 3.5 331 156
Volume Equivalent 5-pH 3.5 325 153
Volume Equivalent 1-pH 3.0 472 30
Volume Equivalent 1-pH 1.0 81 <4
Volume Equivalent 3-pH 1.0 22 3.0
- Retentate after Diafiltration42 2.0
The results shown in Table 13 are contrary to theoretical in which greater
than
95% of the metal ions should have passed through the membrane after five
volume
equivalents if no polymer/metal ion interactions were taking place. Analysis
results
for other metal ions indicate that at a pH of 3.5 all metal ions except copper
and iron
also began to release. The pH of the retentate was then lowered a second time
to 3Ø
The first volume equivalent of permeate during the second diafiltration
process at pH
3.0 gave a nickel and zinc metal ion concentration of 472 ppm and 30 ppm,
respectively. These results confirm that significant polymer/metal ion
interactions
were still taking place at pH 3.5. The pH of the retentate was lowered a third
time to
pH 1. The nickel concentration in the permeate was 81 ppm in the first volume
equivalent and down to 22 ppm after the third volume equivalent.
Analysis of the retentate after the diafiltration process indicated that more
of the
nickel (42 ppm) was retained than zinc (1.9 ppm) which suggests that there was
a
stronger interaction between the polymers with nickel than with zinc (as shown
from
Example 11 for polymer C). Of the five metal impurities added to the simulated
rinse
water solution, only copper and iron were found to be significantly
concentrated in the
retentate at 17.5 ppm and 26.3 ppm, respectively. While iron showed no
indication of
being released from the polymer at low pH, the copper concentration in the
first
volume equivalent collected at pH = 1 was 14.01 ppm. Chromium(III). which
should
have eluted completely at pH 3 (according to previous results), distributed in
all
fractions and a substantial amount was still present in the final retentate.
This
indicated a kinetic effect as maybe the chromium was slowly being released
from the
polymer during all the diafiltration steps.
CA 02221703 1997-11-19
WO 96/38220 6g PCT/LTS96/08143
Several conclusions can be drawn from the results of the experiment. First,
the
optimum release of the nickel and zinc occurred at or below a pH of 3Ø
Diafiltration
at this pH will reduce the number of volume equivalents needed to recover >95
% of
the nickel and zinc in the concentrated rinse waters. Second, of the five
impurity
metals added to the simulated rinse water solution, copper and iron can be
retained by
the polymer mixture and separated from nickel and zinc at pH 3 under these
process
conditions. The copper and iron can be stripped at lower pH values and/or 0.1
M
chloride solutions to regenerate the polymer mixture. Third, these results
again
indicate how important the counter ion is in the process, not only the type of
ion but
its concentration. The experiment from Example 11 indicated that at 0.1 M
chloride
only chromium(III) and aluminum(III) should elute at pH 3. Under lower
chloride
concentration as in this real electroplating rinse solution, lead and cadmium
also
eluted at pH 3 along with the zinc, nickel, chromium and aluminum. To retain
the
cadmium and lead, the elution could be performed in 0.1 M ammonium chloride to
recover zinc and nickel selectively.
EXAMPLE 14
Recovery of zinc and nickel from electroplating rinse baths containing lead,
cadmium, copper, iron, and aluminum metal ion impurities plus borate, ammonium
and chloride ions (three polymer system): Retention studies were performed on
dilute
electroplating bath solutions to evaluate a three polymer formulation's
effectiveness, in
retaining the electroplating metals in the presence of other bath
constituents. The
composition of the bath used was made according to Table E as the zinc and
nickel
alloy bath. Surfactant was left out of the solution since it would be removed
prior to
ultrafiltration. The bath was diluted 1:100 to simulate rinse waters resulting
in nickel
and zinc metal ion concentrations in the range of 180 ppm and 90 ppm,
respectively.
The concentrations of the other species in solution were diluted in the same
proportions. The general procedure for retention studies involved the addition
of an
excess of purified polymer formulation (90% polymer A, 5% polymer C, and 5%
polymer E) to the dilute rinse waters. The solutions were adjusted to the
desired pH
(1-7) and ultrafiltered through a 10,000 MWCO polysulfone membrane using a
centricon unit. The permeates were analyzed for nickel, zinc and trace metals
by ICP-
AES. The original metal ion concentrations were approximately 5 ppm for the
trace
metals and 25 ppm for the concentrated metal ions. The results are shown in
Table
14.
CA 02221703 1997-11-19 '
WO 96/38220 ' PCT/US96/08143
Table 14. Concentration of metal ions in permeate of a simulated
electroplating
rinse bath after treatment with a 3-polymer formulation.
Elements pH 2.05 pH 3.03 pH 7.10
Cu 0.33 0.04 0.03
Ni 29.6 23.9 0.04
1.78 0.44 <0.0I
Fe 0.17 0.09 <0.01
Cr 2.82 1.66 0.05
_. Zn 16.3 15.9 <0.01
. _.. Pb 5.71 5.33 ' <0.01
Cd 6.33 6.09 0.02
It can be seen from the data in Table 14 that the three polymer system had
excellent metal ion recovery at pH 7 for all the metals and that at the
stripping pH
values of 3 and 2 that all of the trace metal ions except lead and cadmium are
very
well retained and the nickel and zinc was readily recovered at this pH. There
was a
large improvement in the retention of aluminum in this three polymer
formulation as
compared to the two polymer formulation of Example 13. The use of selective
stripping solutions as explained in Example 13 could also be used with the 3-
polymer
system to enhance selectivity.
EXAMPLE 15
Recovery of zinc and tungsten from electroplating rinse baths: Retention
studies
were performed on electroplating rinse solutions to evaluate the individual
polymer's
effectiveness in retaining the electroplating metals in the presence of other
bath
constituents. The composition of the bath used was made according to Table L
the
nickel/tungsten alloy bath. The electroplating bath solution (1.5 mL) was
diluted to
500 mL to give approximately 100 ppm of nickel and tungsten solution. Either
polymer A or polymer B were added to make a 0.02 wt/vol% solution in polymer.
The pH was adjusted with HCl or NaOH to give 25 mL samples ranging from pH 1
to
12. The solutions were filtered in a stirred cell at 60 psi, 10,000 MWCO
membrane,
and the permeate collected for analysis by ICP-AES. The results are shown in
Table
15. It can be seen that both polymers gave reasonable recovery of both nickel
and
tungsten with polymer A being the best performer at near neutral pH, which
would be
CA 02221703 1997-11-19
. _
WO 96/38220 PCT/L1S96/08143
71
the normal pH of electroplating rinse water. Sulfate, a dioxoanion itself, did
not
appear to interfere with the tungsten metal ion recovery. Tungstate, which is
also a
dioxoanion (in these electroplating baths); would be better stripped at high
pH values.
Table I5. Percent nickel and tungsten retained for polymers A and B.
~H polymer of mer A of mer B polymer
A ~ B
%Ni I % %Ni I %W fVI~
W (VI)
1.0 66.8 97.1 69.0 ppt
2.0 78.9 99.3 69.9 ppt
3.0 76.3 99.5 95.1 66.5
4.0 84.3 98.7 98.0 67.2
5.0 100 98.9 98.4 72.8
6.0 100 98.1 99.1 80.8
7.0 100 99.2 98.9 80.7
8.0 100 98.3 -- -
9.0 100 94.6 - ---
10.0 100 87.3 -- --
1 1 nn
1 1VU 90.3 --
A ~
1
t.V
12.0 100 82.6 -- --
Other oxoanions, e.g., chromate, tungstate, molybdate, selenate, and arsenate
(group Via, VIIa, Vb, Vib ions), were tested with polymer A, polymer P, and
polymer
Q. These results are shown in Table 16. Thz solutions were prepared for these
tests
using polymer in 10 times excess to the metal ions in the 500 to 1000 ppm
range
prepared from their sodium salt. The solutions were ultrafiltered using the
same
stirred cell as described above and all samples (retentate and permeate) were
analyzed
by ICP-AES.
CA 02221703 1997-11-19 "~
R'O 9fif38220 ' ~2 PGT/US96/08143
Table 16. Percent retention of oxoanions (VI valent state).
pH Poly- Poly-Poly- Poly-Poly- Poly-Poly- Poly-Poly-Poly-Poly_
mer merQ mer mer mer mer mer mer mer mer mer
Q Q A A A A P P P
P.
%AS %Cr %W %Cr %AS %M0 %W %AS %Cr %V~' %M0
5. 55.3 95 59.6 99.6 99.7 31.5 99.6 93.2
5.0 _
6.0
_ _
7.0 57.8 66.9 89 ---- 54.6 96.3 5.8 53.8 ~ 97.0 72.0
8.0 66.3 ---- 80.3 77.0
9.0 40.8 74.0 64 57.0 40.4 68.3 5.8 34.8 64.5 77.4 55.7
10.0
EXAMPLE 16
". Silver recovery from photofinishing waste solutions: Waste water was
obtained
from a photofinishing laboratory at Los Alamos National Laboratory which
contained
all the rinse waters and photoprocessing solutions. The waste stream treated
contained 464 ppm silver along with other materials common to photography
waste as
shown in Table H. This waste solution was treated with 0.25 wt/vol% polymer A,
adjusted to the pH with nitric acid or sodium hydroxide, and filtered through
a
Centricon-10 (Amicon) unit with a 10,000 MWCO membrane. The results are shown
in Table 17. It can be seen that silver was retained (> 90%) at lower pH
values which
indicates that it is being bound as the anion in this example, probably as the
thiosulfate.
Table 17 Recovery of silver from photofininshing waste stream.
~H_ Ag npm in permeate
4 37
58
6 129
8 460
9 440
464 ppm silver in starting waste solution
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
73
EXAMPLE 17
Recovery of metal ions from acid mine drainage waters: Samples of mine
drainage water from the Berkeley Pit, Butte, Montana were obtained. The sample
has
the analysis as shown in Table 'G. The sample was very high in iron and
aluminum.
The next most abundant metal ions were copper and zinc. There are several
strategies
to treating the waste. One was to remove all metal ions from the waste stream
meeting discharge limits into the local streams or sewer system. The other
approach
was the recovery of metal values at the same time that discharge limits were
being
met. The solution was treated with a series of polymers and polymer
formulations to
recover all the metals both trace (< 10 ppm) and major metals. Iron was
considered a
nuisance metal and there were several strategies to remove it first by some
precipitation step so that it would not saturate the polymers capacity to bind
the other
metals. Aluminum was partly considered a nuisance unless it might have some
metal
value assuming it could be recovered in a pure form. Thus, for these studies,
it too
was partly removed by precipitation. Thus, the sample was first treated with
dilute
base to raise the pH from,2.8 to 4 to allow a large portion of the iron and
some
aluminum to precipitate. The resulting solution had the metal analysis shown
in Table
18. The solution was also treated in several ways to determine an effective
way to
remove all toxic metals and to potentially recover valuable metals. These
treatments
are also shown in Table 18. It can be seen that the use of polymer A to
precipitate
iron and aluminum was most effective. The polymer A then bound metals such as
copper, as indicated by the bright blue color of the solution. It was assumed
that
further addition of polymer A and/or raising the pH to 6 or 7 would then bind
zinc and
the rest of the copper for further separation by ultrafiltration.
CA 02221703 1997-11-19 -
WO 96138220 ' PCT/US96/08143
74
'fable 18. Metal content in ppm of Berkeley Pit Mine Drainage water after
various treatments.
Ele- Un- After - After KOH After After After
ment treated NaOH nH 3.8** NH40H Polymer polymer
* A C
sample pH 3.0** pH 3.8** pH 4.8** pH 5
6***
nH 2.62-6 .
Fe 17.21 4.47(26%) 2.97(17%) 0.02(<1%)0.0(<1%) <0.Q1
Mn 3.99 4.12(103%)
A1 5.92 4.51 (76%)4.29(72%) 3.64(62%)0.31 (5%) <0.01
Cu 3.74 3.33(89%) 3.25(87%) 3.04(81%)3.04(81%) <0.01
Mg. 8.82 8.7(98%)
.
Zrr- 10.74 10.95(103%)10.8(100%)9.82(92%)11.2(104%)<Q
O1
*m"o~~..e .
.~...
..~
~.~.., cu,. um. CuttvUill 11 lrl~ or eacn metal In 1U mL of Berkeley Pit
water.
* * Values are reported as mg of metal remaining in solution after
precipitation
from 20 mL of Berkeley Pit Water. Values in parenthesis are the percent of
metal
remaining in solution based on original Berkeley Pit water.
***Sample from NaOH precipitation treated with 0.12% weight polymer.
EXAMPLE 18
Recovery of technetium from aqueous streams: Technetium (Tc) exists in a
variety of waste waters in the nuclear industry, in ground water plumes, and
in nuclear
medicine wastes. An example waste stream that has large quantities of Tc is in
the
Hanford Tanks at Hanford, WA, at the nuclear facility. Though the tanks have
varied
compositions they typically are very high in salts and a typical simulant is
given in
Table K. In contrast, ground water will have low salt content and few
competing ions.
A variety of permethylated polymers (polyvinylamine, polyallylamine,
polyethyleneimine and poly(vinylpyridine))(polymers N, O, Q, S, and Sa) and
crown
ether-containing polymers (polymer L and M) were tested for their ability to
recover
technetium from a variety of aqueous solutions representing from clean-water
aquifers
to brine solutions to basic solutions.
The polymers were dissolved in water to give from 0.05 to 0.3 wt/vol%
solutions.
The solutions were spiked with Tc-95m. After mixing, from 1 to 2 mL of the
solutions were ultrafiltered in a Centricon OF unit. A blank test was
performed
similar to above without polymer and was determined to have minimal holdup in
the
Centricon unit. The top (retentate) and bottom (permeate) of the units were
counted
on a NaI detector. The formula as given in Example 1 was used to calculate Kd
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
values. The results are summarized in Table 19. For the permethylated
materials, the
extraction was best at low ionic strength.
Table 19. Summary of selected polymers' retention of technetium.
Po~mer Condition Kd
Permethylated Polyethyleneimine-S04 0.5 M N03, pH 7 73
Polymer Q
Permethylated Polyethyleneimine-S04 0.1 M N03, pH 7 260
Polymer Q
Permethylated Polyethyleneimine-S04 0.01 M N03, pH 2384
Polymer Q 7 '
Permethylated Polyethyleneimine-S04 0.005 M N03, pH 4548
Polymer Q 7
Permethylated Polyethyleneimine-S04 0.0 M N03, pH 7 20788
Polymer Q
Permethylated Polyvinylamine-Cl, 0.1 M N03, pH 7 205
Polymer N -
Permethylated Polyvinylamine-Cl, 0,01 M N03; pH 1310
Polymer N 7
Permethylated Polyvinylamine-Cl, 0.005 M N03, pH 2394
Polymer N 7
Permethylated Polyvinylamine-Cl, 0.0 M N03, pH 7 12900
Polymer N
Permethylated Polyvinylamine-Cl, pH 13 (with NaOH) 700
Polymer N
Permethylated Polyvinylarliine-Cl, pH 1.5 (with HN03)470
Polymer N
Permethylated Polyallylamine-Cl, 0.5 M N03, pH 7 83
Polymer O
Permethylated Polyallylamine-Cl, 0.1 M N03, pH 7 243
Polymer O
Permethylated Polyallylamine-Cl, 0.01 M N03, pH 2485
Polymer O 7
Permethylated Polyallylamine-Cl, 0.005 M N03, pH 7979
Polymer O 7
Permethylated Polyallylamine-Cl, 0.0 M N03, pH 7 60570
Polymer O
Polyvinylpyridinium-Cl, Polymer Sa 0.5 M N03, pH 7 82
Polyvinylpyridinium-Cl, Polymer Sa 0.1 M N03, pH 7 231
Polyvinylpyridinium-Cl, Polymer Sa 0.01 M N03, pH 2202
7
Polyvinylpyridinium-Cl, Polymer Sa 0.005 M N03, pH 3592
7
Polyvinylpyridinium-Cl, Polymer Sa 0.0 M N03, pH 7 23246
Polyvinylpyridinium-I, Polymer S 0.1 M N03, pH 7 154
Polyvinylpyridinium-I, Polymer S 0.01 M N03, pH 823
7
Polyvinylpyridinium-I, Polymer S 0.005 M N03, pH 1246
7
Polyvinylpyridinium-I, Polymer S 0.0 M N03, pH 7 8703
Crown 1, Polymer L 2.6 M KN03, pH 44
7
_
Crown 2, Polymer M ~ 1 M NaOH 28
EXAMPLE 19
Recovery of metal ions from textile waste waters was tested as follows:
Textile
waste waters were obtained and have the composition shown in Table M. Polymer
was added to the solution to make the solution 0.4 wdvol% in polymer and the
solutions were mixed. No pH adjustment was made. The solutions (2 mL) were
CA 02221703 1997-11-19 ~'-
WO 96/38220' ~6 PC'T/US96l08143
filtered through the 10,000 MWCO Centricon units used in the other examples
and
the permeate was analyzed for metal content by ICP-AES. As can be seen from
the
results in Table 20, the Cu and Cr were removed to below most discharge
limits.
Table 20. Recovery of metals from textile waste waters.
Sample ~ Sam Sample 2 Sample 3
pH 10.7 4.5 4.5
Primary heavy Cu (575 ppm) Cu ( 1000 ) Cr ( 1000 )
metal (mg/L)
After TreatmentCu <0.1 ppm Cu 0.19 ppm -_--_
with polymer
A
After Treatment----- ---- Cr 0.03 ppm
with polymer
C
EXAMPLE 20
Sulfur containing water-soluble polymers were tested for a variety of
transition
metals. A stock solution of polymer was prepared by dissolving 1.00 g of the
selected
polymer in 40 mL of millipore water. A stock solution of metals was prepared
by
mixing 5 mL each of the appropriate 1000 ppm ICP standard in a 50 mL
volumetric
flask and bringing the volume to the mark. The ionic strength adjustment
solution
was prepared by dissolving 10.62 g (0.125 moles) NaN03 in a 50 mL volumetric
flask and diluting to the mark.
The sample was prepared by mixing in a plastic beaker 5 mL of the stock metal
solution, 5 mL of the stock polymer solution, 2 mL of the 2.5 M NaN03 solution
and
20 mL of millipore water. The pH was brought to the appropriate value by the
addition of 0.1 M NaOH. After allowing the mixture'to equilibrate for 30
minutes, it
was added to a 50 mL volumetric flask, washed in with 3 X 2 mL water and
diluted to
the mark. The solution was then transferred to a 50 mL stirred ultrafiltration
cell with
a 10,000 MWCO filter. The first 10 mL of permeate was discarded and the next
I2
mL was collected for analysis by ICP. The procedure was repeated separately
for
each pH and each polymer (polymers Y, Z and AA) and the results are summarized
in
Table 21.
Table 21. Binding of metals by sulfur containing derivatives of
polyethyleneimine.
(% metal bound vs pH)
Polymer Z
CA 02221703 1997-11-19
WO 96/38220 PCT/US96/08143
77
pH Cu Fe Ni Co Zn Cd Pb Mn
2 68 20 0 0 0 0 0 0
3 100 32 2 4 1 3 3 7
4 100 92 16 12 2 5 25 5
100 100 98 83 22 17 20 3
6 100 100 100 96 100 100 88 '3
7 100. 100 100 90 100 100 100 0 .
Polymer AA
pH Cu Ni Co Fe Mn Zn Cd Pb
2 100 0 0 0 0 0 0 0
3 100 2 6 11 3 3 10 ' 18
4 100 S 8 96 5 4 22 28
5 100 64 27 99 7 13 73 39
6 100 100 91 100 9 92 100 75
7 100 100 100 100 17 100 100 100
Polymer Y
pH Pb Cu Fe Cd A~ Ni Ma Mn Zn Ca
1 2 0 1 1 100 9 4 3 5 0
3 96 75 0 97 100 4 10 0 28 2
5 99 100 22 100 100 55 7 12 80 0
7 -99 100 94 99 100 92 -// 32 98 19
- -
9 99 100 100 97 99 98 20 70 97 40
EXAMPLE 21
An experiment simulating cooling tower water evaporation was performed. Tap
water (1000 mL, from Espanola, NM) was evaporated under low vacuum on a
rotavap
at SOoC just until solid scale started to precipitate (concentrated to 775 mL)
and
caused the water to become cloudy. To another 1000 mL of tap water was added
the
polymer from example C to give a 0.1 wt/vol% solution. The second solution was
treated the same as the first but this time the solution was evaporated to 480
mL
before any precipitation was observer, indicating that the polymer can keep
dissolved
hardness ions in solution possibly reducing scale.
Further experimentation with pure water ( 15 mL) to which had been added
calcium carbonate (50 ppm) and the polymer in example C (0.1 wt/vol%) at pH
7.5.
indicated that upon ultrafiltration using a centricon unit such that half of
the solution
was filtered, that 525.0 ug of calcium was in the retentate and 157.5 ug was
in the
permeate. This indicates that under neutral to slightly basic conditions that
calcium is
somewhat retained and that this process could be used to remove calcium or
scale-
forming metal ions from cooling tower waters or other process waters.
EXAMPLE 22
CA 02221703 1997-11-19 w~
WO 96/38220' PCT/LTS96108I43
78 .
Acetylpyrazolone (polymer F) and diamlde (polymer R) containing polymers
were tested with a variety of transition metal ions. Solution ( I S mL)
containing 10
ppm of metal ions was made 0.1 wt/vol% in polymer. The ionic strength was
maintained at 0.1 with ammonium sulfate. The solution was filtered through a
Centraprep (Amicon, cellulose membrane) unit with a 10,000 MWCO until half of
the
volume was filtered. The permeates were measured for metal content using ICP-
AES.
The results are given in the accompanying Tables 22. A blank under the same
conditions in the absence of polymer is also shown. The retention of certain
metals at
high pH values are where the metal hydroxide precipitates from solution and
the
material is collected as a solid.
CA 02221703 1997-11-19
WO 96/38220 PGT/US96/08143
79
Table
22.
Metal
concentration
in
the
permeate.
Polymer
F
pHAI Cd Cr Cu Fe Ni Pb Zn
1 84.57 91.93 92.29 63.87 97.56 92.42 90.06 90.73
2 76.21 91.93 91.28 12.57 96.62 85.03 88.18 90.73
3 60.41 95.68 92.29 4.19 82.55 35.12 93.81 91.72
4--~l:Fs2-58.16 91.28 8.38 72.23 10.17 62.85 53.25
28.81 10.32 65.92 7.33 47.84 7.39 15.01 7.89
6 4.65 7.50 3.04 6.28 7.50 7.39 9.38 5.92
7 0.93 6.57 0.00 6.28 6.57 6.47 3.75 5.92
1076.21 6.57 0.00 9.42 6.57 7.39 0.00 8.88
Polymer
R
nHA1 Cd Cr Cu Fe Ni Pb Zn
1 87.73 97.47 1 OO.IO91.10 96.72 96.30 99.81 97.44
~
2 94.33 100.0093.71 87.96 93.15 94.55 101.59100.10
3 89.41 91.84 98.28 22.62 87.90 90.48 96.44 93.10
4 86.06 89.87 81.95 1.05 25.23 91.13 90.43 95.27
5 13.29 86.40 8.11 0.00 2.25 50.18 80.68 91.72
6 0.0 65.20 0.10 0.00 0.38 9.24 37.15 71.70
~ 0.0 6.29 -0.00 -0.21 0.00 1.29 2.72 13.61
1072.49 17.07 0.51 0.94 0.00 5.27 0.00 49.01
Nopolymer
(blank)
pHAl Cd Cr Cu Fe Ni Pb Zn
1 98.96 99.95 100.00100.00 94.73 98.88 100.00
100.00
2 97.77 98.02 99.24 97.07 98.97 93.35 96.93 92.87
3 90.06 96.61 99.78 91.62 93.71 96.21 98.98 96.85
~
4 86.43 98.87 88.50 89.11 37.05 92.88 97.49 97.93
S 33.09 100.0023.64 83.46 0.56 100.00100.0099.01
6 0.93 99.53 0.22 52.04 0.00 98.15 51.58 94.98
~
7 0.00 95.38 0.00 22.09 0.00 96.77 7.26 70.64
1073.05 82.00 0.00 85.55 0.00 93.81 1.77 64.04
EXAMPLE 23
A 0.1 wdvol % solution of the polymeric hydroxamic acid from example I, was
prepared at each of the pH values 2, 6 and 8. Each solution was spiked with
americium and filtered in a 10,000 MWCO ultrafiltration membrane. Almost no
retention of the americium was observed at the lower pH values, but 99%
retention
was observed at the pH of 8. Thus, polymeric hydroxamic acid can bind an
actinide
such as americium under conditions of pH 8.
EXAMPLE 24
CA 02221703 1997-11-19 ,
WO 96!38220 PCT/L1S96l08143
80 .
Binding studies of beta-bisphosphonates as diacid (polymer X), acid-ester
(polymer I~ and diester (polymer V) were as follows. The same procedure as in
Example 1 was followed to evaluate these polymers for americium binding, The
polymers were prepared at 0.1 wdvol% in sodium nitrate solution to an ionic
strength
of 0.1 and spiked with Am-241. The results are shown in Table 23 below.
Polymer
E, a different phosphoric acid containing polymer, is also,shown in the Table
for
comparison. It can be seen that the americium binding order is the diacid >
acid-ester
> diester, and that the beta-bisphosphonic acid binds better at pH 2 than
polymer E
which is not a beta-bisphosphonic acid.
Table 23 Study of polymers V, W and X for binding of americium-241
PH Polymer E Polymer Y Polymer W Polymer X
Log ~ Log Kd Log K,, Log K,,
2 3.94 1.64 2.73 4
22
4 4.81 3.3 3.63 .
4
22
6 4.91 3.87 4.14 .
4.4I
EXAMPLE 25
To demonstrate the concept that two different molecular weight polymers having
different functionality could be separated, two polymers were mixed in a ratio
of
20:80 to give an overall 5 wdvol% solution of polymer. Using polymer prepared
as in
example A, >100,000 MWCO and polymer Ca of between 10,000 and 30000 MWCO
prepared as in example C, 100 mL were diafiltered through a 30,000 MWCO
membrane at pH 6.0 collecting 3 volume equivalents which were evaporated to
dryness and weighed. The recovery of solid polymer Ca was only 23% after 3
volume
equivalents were collected. A blank of a 5 wdvol% solution of polymer Ca gave
15%
permeate (evaporated solid and weighed) after 3 volume equivalents. Though in
the
experiment only a small amount of material was collected, it indicated that
size
separation of two polymers was possible.
Although the present invention has been described with reference to specific
details, it is not intended that such details should be regarded as
limitations upon the
scope of the invention, except as and to the extent that they are included in
the
accompanying claims.
