METAL SCAVENGING POLYMERS AND USES THEREOF
FIELD OF THE INVENTION
The field of the invention pertains to novel metal scavenging polymers and uses thereof.
BACKGROUND OF THE INVENTION
Metal scavenging for various mediums, such as process water and air have been a
challenge for various industries, including heavy and light industry, such as power plants and
mining operations. In addition, metal scavenging for process waters have been an object for
municipal applications as well.
On-going investigations for improved metal scavenging technology have been desired by
various industries. The present disclosure addresses various avenues for handling metals
management in industrial and municipal processes. These chemistries could be potentially
utilized for other various applications that require metal scavenging. .
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a general schematic of a portion of a wastewater treatment system.
SUMMARY OF THE INVENTION
The present disclosure provides for a composition comprising a polymer derived from at
least two monomers: acrylic-x and an alkylamine, wherein said acrylic-x has the following
formula:
wherein X = OR, OH and salts thereof, or NHR2 and wherein and R2 is H or an alkyl or aryl
group, wherein R is an alkyl or aryl group, wherein the molecular weight of said polymer is
between 500 to 200,000, and wherein said polymer is modified to contain a functional group
capable of scavenging one or more compositions containing one or more metals.
The present disclosure also provides for a method of removing one or more metals from a
medium containing these metals which comprises the steps of: (a) treating said medium
containing metals with a composition comprising a polymer derived from at least two monomers:
acrylic-x and an alkylamine, wherein said acrylic-x has the following formula:
wherein X = OR, OH and salts thereof, or NHR2 and wherein R and R2 is H or an alkyl or aryl
group, wherein the molecular weight of said polymer is between 500 to 200,000, and wherein
said polymer is modified to contain a functional group capable of scavenging one or more
compositions containing one or more metals; (b) and collecting said treated metals.
DETAILED DESCRIPTION OF THE INVENTION
A. Compositions
The present disclosure provides for a composition comprising a polymer derived from at
least two monomers: acrylic-x and an alkylamine, wherein said acrylic-x has the following
formula:
wherein X = OR, OH and salts thereof, or NHR2 and wherein and R2 is H or an alkyl or aryl
group, wherein R is an alkyl or aryl group, wherein the molecular weight of said polymer is
between 500 to 200,000, and wherein said polymer is modified to contain a functional group
capable of scavenging one or more compositions containing one or more metals.
The metals can include zero valent, monovalent, and multivalent metals. The metals may
or may not be Hgated by organic or inorganic compounds. Also, the metals can be radioactive
and nonradioactive. Examples include, but are not limited to, transition metals and heavy metals.
Specific metals can include, but are not limited to: copper, nickel, zinc, lead, mercury, cadmium,
silver, iron, manganese, palladium, platinum, strontium, selenium, arsenic, cobalt and gold.
The molecular weight of the polymers can vary. For example, the target
species/application for the polymers can be one consideration. Another factor can be monomer
selection. Molecular weight can be calculated by various means known to those of ordinary skill
in the art. For example, size exclusion chromatography, as discussed in the examples below can
be utilized.
When molecular weight is mentioned, it is referring to the molecular weight for the
unmodified polymer, otherwise referred to as the polymer backbone. The functional groups that
are added to the backbone are not part of the calculation. Thus the molecular weight of the
polymer with the functional groups can far exceed the molecular weight range.
In one embodiment, the molecular weight of the polymer is from 1,000 to 16,000.
In another embodiment, the molecular weight of said polymer is from 1,500 to 8,000.
Various functional groups can be utilized for metal scavenging. The following
phraseology would be well understood by one of ordinary skill in the art: wherein said polymer is
modified to contain a functional group capable of scavenging one or more compositions
containing one or more metals. More specifically, the polymer is modified to contain a
functional group that can bind metals.
In one embodiment, the functional group contains a sulfide containing chemistry.
In another embodiment, the functional group is a dithiocarbamate salt group.
- In another embodiment, the functional groups are at least one of the following:alkylene
phosphate groups, alkylene carboxylic acids and salts thereof, oxime groups, amidooxime
groups, dithiocarbamic acids and salts thereof, hydroxamic acids, and nitrogen oxides.
The molar amounts of the functional group relative to the total amines contained in the
unmodified polymer can vary as well. For example, the reaction of 3.0 molar equivalents of
carbon disulfide to a 1.0: 1.0 mole ratio acrylic acid / TEPA copolymer, which contains 4 molar
equivalents of amines per repeat unit after polymerization, will result in a polymer that is
modified to contain 75 mole % dithiocarbamate salt group. In other words, 75 % of the total
amines in the unmodified polymer has been converted to dithiocarbamate salt groups.
In one embodiment, the polymer has between 5 to 00 mole % of the dithiocarbamate salt
group. In a further embodiment, the polymer has from 25 to 90 mole % of the dithiocarbamate
salt group. In yet a further embodiment, the polymer has from 55 to 80 mole % of the
dithiocarbamate salt group.
Monomer selection will depend on the desired polymer that one of ordinary skill in the art
would want to make.
The alkylamines may vary in kind.
In one embodiment, the alkylamine is at least one of the following: an ethyleneamine, a
polyethylenepolyamine, ethylenediamine (EDA), diethylenetriamine (DETA),
triethylenetetraamine (TETA) and tetraethylenepetamine (TEPA) and pentaethylenehexamine
(PEHA).
The acrylic-x monomer group can vary as well.
In another embodiment, the acrylic-x is at least one of the following: methyl acrylate,
methyl methacrylate, ethyl acrylate, and ethyl methacrylate, propyl acrylate, and propyl
methacrylate.
In another embodiment, the acrylic-x is at least one of the following: acrylic acid and salts
thereof, methacrylic acid and salts thereof, acrylamide, and methacrylamide.
The molar ratio between monomers that make up the polymer, especially acrylic-x and
a kyla ine can vary and depend upon the resultant polymer product that is desired. The molar
ratio used is defined as the moles of acrylic-x divided by the moles of alkylamine.
In one embodiment, the molar ratio between acrylic-x and alkylamine is from 0.85 to 1.5.
In another embodiment, the molar ratio between acrylic-x and alkylamine is from 1.0 to
1.2.
Various combinations of acrylic-x and alkylamines are encompassed by this invention as
well as associated molecular weight of the polymers.
In one embodiment, the acrylic-x is an acrylic ester and the alkylamine is PEHA or TEPA
or DETA or TETA or EDA. In a further embodiment, the molar ratio between acrylic-x and
alkylamine is from 0.85 to 1.5. In yet a further embodiment, the molecular weight can
encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000. In yet a further
embodiment, the acrylic ester can be at least one of the following: methyl acrylate, methyl
methacrylate, ethyl acrylate, and ethyl methacrylate, propyl acrylate, and propyl methacrylate,
which is combined with at least one of the alklyamines, which includes PEHA or TEPA or
DETA or TETA or EDA. In yet a further embodiment, the resulting polymer is modified to
contain the following ranges of dithiocarbamate salt groups: 5 to 100 mole %, 25 to 90 mole %,
55 to 80 mole %.
In another embodiment, the acrylic-x is an acrylic amide and the alkylamine is TEPA or
DETA or TETA or EDA. In a further embodiment, the molar ratio between acrylic-x and
alkylamine is from 0.85 to 1.5. In yet a further embodiment, the molecular weight can
encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000. In yet a further
embodiment, the acrylic amide can be at least one or a combination of acrylamide and
methacrylamide, which is combined with at least one of the alklyamines, which includes PEHA
or TEPA or DETA or TETA or EDA. In yet a further embodiment, the resulting polymer is
modified to contain the following ranges of dithiocarbamate salt groups: 5 to 100 mole %, 25 to
90 mole %, or 55 to 80 mole %.
In another embodiment, the acrylic-x is an acrylic acid and salts thereof and the
alkylamine is PEHA or TEPA or DETA or TETA or EDA. In a further embodiment, the molar
ratio between acrylic-x and alkylamine is from 0.85 to 1.5. In yet a further embodiment, the
molecular weight can encompass ranges: 500 to 200,000, 1,000 to 16,000, or 1,500 to 8,000. In
yet a further embodiment, the acrylic acid can be at least one or a combination of acrylic acid or
salts thereof and methacrylic acid or salts thereof, which is combined with at least one of the
alklyamines, which includes TEPA or DETA or TETA or EDA. In yet a further embodiment, the
resulting polymer is modified to contain the following ranges of dithiocarbamate salt groups: 5
to 100 mole %, 25 to 90 mole %, or 55 to 80 mole %.
Additional monomers can be integrated into the polymer backbone made up of
constituent monomers acrylic-x and alkylamine. A condensation polymer reaction scheme can
be utilized to make the basic polymer backbone chain. Various other synthesis methods can be
utilized to functionalize the polymer with, for example, dithiocarbamate and/or other non-metal
scavenging functional groups. One of ordinary skill in the art can functionalize the polymer
without undue experimentation.
Moreover, the composition of the present invention can be formulated with other
polymers such as those disclosed in U.S. Patent No. 5,164,095, herein incorporated by reference,
specifically, a water soluble ethylene dichloride ammonia polymer having a molecular weight of
from 500 to 100,000 which contains from 5 to 50 mole % of dithiocarbamate salt groups. In one
embodiment, the molecular weight of the polymer is from 1500 to 2000 and contains 5 to 50
mole % of dithiocarbamate salt groups. In a further embodiment, the molecular weight of the
polymer is from 1500 to 2000 and contains 25 to 40 mole % of dithiocarbamate salt groups.
Also, the composition of the present invention can be formulated with other small
molecule sulfide precipitants such as sodium sulfide, sodium hydrosulfide, TMT-15® (sodium or
calcium salts of trimercapto-S-triazine; Evonik Industries Corporation 1721 1 Camberwell Green
Lane, Houston, TX 77070, USA), dimethyldithiocarbamate and diethyldithiocarbamate.
B. Dosage
The dosage of the disclosed polymers for use may vary. The calculation of dosage
amounts can be done without undue experimentation.
Process medium quality and extent of process medium treatment are a couple of factors
that can be considered by one of ordinary skill in the art in selecting dosage amount. A jar test
analysis is a typical example of what is utilized as a basis for determining tbe amount of dosage
required to achieve effective metals removal in the context of a process water medium, e.g.
wastewater.
In one embodiment, the amount of modified polymer of the invention capable of
effectively removing metals from contaminated waters is preferably within the range of 0.2 to 2
moles of dithiocarbamate per mole of metal. More preferably, the dosage is 1 to 2 moles of
dithiocarbamate per mole of metal contained in the water. According to one embodiment of the
invention, the dosage of metal removal polymer required to chelate and precipitate 100 ml of 1
ppm soluble copper to about 1 ppm or less was 0.01 1 gm ( 1.0 mg) of polymer. The metal
polymer complexes formed are self flocculating and quickly settle. These flocculants are easily
separated from the treated water.
In the context of applying the polymer to a gas system, such as a flue gas, the polymer
can be dosed incrementally and capture rates for a particular metal, e.g. such as mercury, can be
calculated by known techniques in the art.
C. Methods of Use
The present disclosure also provides for a method of removing one or more metals from a
medium containing these metals which comprises the steps of: (a) treating said medium
containing metals with a composition comprising a polymer derived from at least two monomers:
acrylic-x and an alkylamine, wherein said acrylic-x has the following formula:
wherein X = OR, OH and salts thereof, or NHR2 and wherein R and R2 is H or an a ky or aryl
group, wherein R is an alkyl or aryl group, wherein the molecular weight of said polymer is
between 500 to 200,000, and wherein said polymer is modified to contain a functional group
capable of scavenging one or more compositions containing one or more metals; and (b)
collecting said treated metals.
The compositions as described above are incorporated into this section and can be applied
within the claimed methodologies encompassed by this invention.
The target metals of interest will depend on the system/medium to be treated.
The metals can include zero valent, monovalent, and multivalent metals. The metals may
or may not be ligated by organic or inorganic compounds. Also, the metals can be radioactive
and nonradioactive. Examples include, but are not limited to, transition metals and heavy metals.
Specific metals can include, but are not limited to at least one of the following: copper, nickel,
zinc, lead, mercury, cadmium, silver, iron, manganese, palladium, platinum, strontium, selenium,
arsenic, cobalt and gold.
In one embodiment, the metals are at least one or a combination of the following: copper,
nickel, zinc, lead, mercury, cadmium, silver, iron, manganese, palladium, platinum, strontium,
selenium, arsenic, cobalt and gold.
In another embodiment, the metals are transition metals.
In another embodiment, the metals are heavy metals.
Mediums containing metals can vary and include at least one of the following wastewater
streams, liquid hydrocarbonaceous streams, flue gas streams, flyash, and other particulate matter.
Various processing steps can be coupled with metals removal, including, but not limited to
filtration steps and/or air quality control devices, e.g. baghouses and electrostatic precipitators
and other air quality control devices.
Mediums containing a liquid phase medium/a medium containing a liquid phase are one
target for the claimed invention.
In one embodiment, the medium is a process stream containing water, e.g. wastewater or
wastewater from a power plant or industrial setting (power plant, mining operation, waste
incineration, and/or manufacturing operation).
In another embodiment, the medium is a liquid hydrocarbonaceous stream common in
petroleum refining processes or petrochemical processes. Examples include streams from these
processes that contain petroleum hydrocarbons such as petroleum hydrocarbon feedstocks
including crude oils and fractions thereof such as naphtha, gasoline, kerosene, diesel, jet fuel,
fuel oil, gas oil vacuum residual, etc or olefinic or napthenic process streams, ethylene glycol,
aromatic hydrocarbons, and their derivatives.
In another embodiment, additional chemistries, flocculants and/or coagulants can be
utilized in conjunction with the chemistry encompassed by this invention. The chemistries
applied to a medium containing metals can vary, including, the addition of at least one of the
following: cationic polymers, anionic polymers, amphoteric polymers, and zwitterionic
polymers.
In another embodiment, the method of this invention further comprises an additional
treatment to the process stream with a complexing amount of a water soluble ethylene dichloride
ammonia polymer having a molecular weight of from 500 to 100,000 which contains 5 to 50
mole % of dithiocarbamate salt groups to form a complex of these metals, e.g. heavy metals. In a
further embodiment, the molecular weight of the polymer is from 1500 to 2000 and contains 15
to 50 mole % of dithiocarbamate salt groups. In yet a further embodiment, the molecular weight
of the polymer is from 1500 to 2000 and contains 25 to 40 mole % of dithiocarbamate salt
groups.
In another embodiment, the polymer treatment and additional treatment are added in a
ratio of 1:1.
Mediums containing a gas phase medium/a medium containing a gas phase are another
target for the claimed invention. In addition, processes containing a liquid and or gas phase
medium are encompassed by this invention as well.
In another embodiment, the medium is part of a heat generating system, e.g. a flue gas
stream.
In another embodiment, the heat generating system is at least one of the following: a
combustion system; a power plant combustion system; a coal combustion system; a waste
incineration system; a kiln; a kiln for mining or cement operations; and an ore processing system.
In another embodiment, the method of this invention further comprises applying an
oxidizing agent to a heat generating system. In a further embodiment, the oxidizing agent is
applied prior to said polymer treatment.
In a yet a further embodiment, a multiphase treatment protocol for a process involves
treating a gas and a liquid, e.g. one or more metals in a gas such as mercury and one or more
metal in a liquid. This can involve the polymer treatment and additional treatment as described
above.
In yet a further embodiment, the oxidizing agent is at least one of the following: a
thermolabile molecular halogen, calcium bromide, or a halogen containing compound.
In yet a further embodiment, this invention further comprises applying an oxidizing agent
to the flue gas; optionally wherein said oxidizing agent oxidizes a target species at a temperature
of 500°C or greater or a temperature where the oxidant is capable of oxidizing molecular mercury
that exists in a process that generates mercury; optionally wherein said target species is elemental
mercury or derivatives thereof; and optionally wherein said oxidizing agent is at least one of the
following: a thermolabile molecular halogen, calcium bromide, or a halogen containing
compound. Mercury oxidant methodologies are described in US Patent Nos. 6,808,692 and
6,878,358, which are herein incorporated by reference.
In another embodiment, the polymer treatment occurs at a temperature 300°C or below,
preferably 250 °C or below.
The following examples are not meant to be limiting.
EXAMPLES
A. Polymer Preparation
Example 1
Methyl Acrylate / Tetraethylenepentamine Polymer Backbone which is then
functionalized with a dithiocarbamate group
a. Methyl Acrylate / Tetraethylenepentamine Polymer Backbone Synthesis
Tetraethylenepentamine (TEPA) (18.275 weight %) was charged into a glass reactor
fitted with a mechanical stirrer and a condenser. While purging the headspace with nitrogen and
stirring, methyl acrylate (16.636 weight %) was added dropwise over 30 min where the
temperature was maintained between 25 - 31° C during the addition and for 1 h after the addition
was finished. Next, a second charge of TEPA (18.275 weight %) was performed and the
resulting reaction mixture was heated to 130° C. This temperature was held for ~ 3 h while
collecting the condensate in a Dean-Stark trap. At this time, the polymer melt was allowed to
cool to 120° C and then slowly diluted with deionized (DI) water (46.814 weight %) keeping the
temperature above 90° C during the dilution. The resulting ~50 weight % polymer solution was
then cooled to room temperature. Weight average molecular weight of the polymer was
determined to be 7,500 using a size exclusion chromatography method and polysaccharide
standards.
b. Dithiocarbamate Polymer Preparation
The second step involved adding the methyl acrylate / TEPA polymer (35.327 weight %),
DI Water (28.262 weight %), and Dowfax 2A1 (0.120 weight %), Dow Chemical Company
Midland, MI 48674, USA, to a round bottom flask fitted with a mechanical stirrer. Next, a 50%
NaOH solution (9.556 weight %) was added to the stirring reaction mixture. Once the mixture
was heated and maintained at 40° C, carbon disulfide (17.179 weight %) was added drop-wise
over 2 h . One hour within the carbon disulfide addition, another amount of 50% NaOH (9.556
weight %) was charged. The reaction mixture was maintained at 40° C for an additional 2 h .
Finally, the reaction was cooled to room temperature and filtered though filter paper to obtain ~
40 weight % polymeric dithiocarbamate product.
Example 2
Acrylic Acid / Tetraethylenepentamine Polymer Backbone which is then functionalized
with a dithiocarbamate group
a. Acrylic Acid / Terraethylenepentamine Polymer Backbone Synthesis
Terraethylenepentamine (TEPA) (37.556 weight %) and sulfuric acid (0.199 weight %)
was charged into a glass reactor fitted with a mechanical stirrer and a condenser. While purging
the headspace with nitrogen and stirring, acrylic acid (14.304 weight %) was added dropwise
over 30 min where the temperature was maintained between 1 0 - 40° C during the addition,
allowing the exotherm from the acid base reaction to reach the desired temperature. Next the
resulting reaction mixture was heated to 160° C. This temperature was held for 4.5 h while
collecting the condensate in a Dean-Stark trap. At this time, the polymer melt was allowed to
cool to 120° C and then slowly diluted with DI water (47.941 weight %) keeping the temperature
above 90° C during the dilution. The resulting 50 weight % polymer solution was then cooled
to room temperature. Weight average molecular weight of the polymer was determined to be
4,700 using a size exclusion chromatography method and polysaccharide standards.
b. Dithiocarbamate Polymer Preparation
The second step involved adding the acrylic acid / TEPA polymer ( 1.477 weight %), DI
Water (36.825 weight %), and Dowfax 2A1 (0.1 18 weight %) to a round bottom flask fitted with
a mechanical stirrer. Next, a 50% NaOH solution (8.393 weight %) was added to the stirring
reaction mixture. Once the mixture was heated and maintained at 40° C, carbon disulfide (14.794
weight %) was added drop-wise over 2 h. One hour within the carbon disulfide addition, another
amount of 50% NaOH (8.393 weight %) was charged. The reaction mixture was maintained at
40° C for an additional 2 h. Finally, the reaction was cooled to room temperature and filtered
though filter paper to obtain ~ 35 weight % polymeric dithiocarbamate product.
Example 3
a. Acrylamide / Tetraethylenepentamine Polymer Backbone Synthesis
Tetraethylenepentamine (TEPA) (14.581 weight %>) was charged into a glass reactor
fitted with a mechanical stirrer and a condenser. While purging the headspace with nitrogen and
stirring, a 48.6 % acrylamide solution (30.441 weight %) was added dropwise over h during
which the desired temperature was reached and was maintained between 65 - 75° C. After the
acrylamide charge, the temperature was maintained for an additional 1 h. Next, a second charge
of TEPA (14.581 weight %) was performed and the resulting reaction mixture was heated to 160°
C while collecting the distilled water via a Dean-Stark trap. This temperature was held for ~ 4 h
while continuing to collect the condensate in a Dean-Stark trap and trapping the released
ammonia side product. At this time, the polymer melt was allowed to cool to 1 0° C and then
slowly diluted with DI water (40.397 weight %) keeping the temperature above 90° C during the
dilution. The resulting ~50 weight % polymer solution was then cooled to room temperature.
Weight average molecular weight of the polymer was determined to be 4500 using a size
exclusion chromatography method and polysaccharide standards.
b. Dithiocarbamate Polymer Preparation
The second step involved adding the acrylamide / TEPA polymer (34.004 weight %), DI
Water (36.518 weight %), and Dowfax 2A1 (0.122 weight %) to a round bottom flask fitted with
a mechanical stirrer. Next, a 50% NaOH solution (7.763 weight %) was added to the stirring
reaction mixture. Once the mixture was heated and maintained at 40° C, carbon disulfide (13.830
weight %) was added drop-wise over 2 h . One hour within the carbon disulfide addition, another
amount of 50% NaOH (7.763 weight %) was charged. The reaction mixture was maintained at
40° C for an additional 2 h. Finally, the reaction was cooled to room temperature and filtered
though filter paper to obtain ~ 35 weight % polymeric dithiocarbamate product.
B. Wastewater Testing Analysis
As stated above, the typical protocol for determining the amount and potential
effectiveness of a polymers ability to scavenge a metal in a process water is through jar test
analysis.
1. Example of method of use on typical 20 ppm C wastewater using jar test
Generally, all polymers were prepared as a 12 weight %polymer solutions in DI water
and prepared fresh on the day of testing. Copper containing water was used for testing.
Six 300 mL samples (jars) of wastewater were placed in 500 mL beakers and set up on a
gang stirrer. The samples of wastewater were mixed at 150 revolutions per minute (rpm) while
the polymer was dosed into the samples. The dosages used were 0.50 g, 0.63 g , 0.75 g, 0.88 g,
and .00 g of polymer solutions prepared as described above. The mixing at 150 rpm was
continued for a total of 10 minutes. This was then followed by a slow mix (35 rpm) for 0
minutes. After the mixing was completed, the precipitate was allowed to settle, undisturbed, for
an additional 10 minutes. Next, the water samples were filtered through 0.45 micron filters. The
filtrate was then acidified to pH = 2 with concentrated nitric acid to stop any further precipitation
of the copper. Residual soluble copper was determined in the filtered water samples by atomic
absorption analysis using copper standards for reference. One set of jars was run for each
polymer tested. Duplicates for several polymers were run and confirmed the reported results.
It should be noted that the observed filtration rates were typically less than 1 minute for
contaminated water treated with the polymer while the filtration rate for water treated with small
molecule metals precipitants, such as trimercapto-S-triazine or dimethyldithiocarbamate, was
typically greater than 2 minutes.
2. Example of method of use on typical Hg wastewater using jar test
Generally, all polymers were prepared as a 5 weight % polymer solutions in DI water and
prepared fresh on the day of testing. Mercury containing water was used for testing.
Six 500 mL samples (jars) of wastewater were placed in 1L beakers and set up on a gang
stirrer. The samples of wastewater were mixed at 300 rpm while the polymer was dosed into the
samples. The dosages used were 0.050 g, 0.100 g, 0.150 g, and 0.250 g of polymer solutions
prepared as described above. The mixing at 300 rpm was continued for a total of 25 mmutes. At
this point, 5 ppm of a cationic flocculant was added and then followed by a slow mix (15 rpm)
for 5 minutes. After the mixing was completed, the precipitate was allowed to settle,
undisturbed, for an additional 45 minutes. Next, the water samples were filtered through 0.45
micron filters. Residual mercury was determined in the filtered water samples according to
United States EPA method 163 1. One set of jars was run for each polymer tested. Duplicates for
several polymers were run and confirmed the reported results.
It should be noted that the observed filtration rates were typically faster than water treated
with small molecule metals precipitants, such as trimercapto-£-triazine or
dimethyldithiocarbamate.
3. Example of performance on typical Cu wastewater using j r tests
C. General Procedures For Use of Polymers in a Wastewater Treatment System
Figure 1 shows a general schematic for a wastewater treatment process. In this particular
figure, the wastewater treatment scheme is based on the treatment of a flue gas desulphurization
chloride purge from a power plant. The polymers of the present invention can be applied to at
least one of the precipitation, coagulation, and flocculation steps.
COMBINATIONS OF COMPONENTS DESCRIBED IN PATENT APPLICATION
In one embodiment, the composition of matter claims include various combinations of the
polymer components such as molecular weight, functional groups, monomer components, and
molar amounts of said components. In a further embodiment, the claimed compositions include
combinations of the dependent claims. In a further embodiment, a range or equivalent thereof of
a particular component shall include the individual component(s) within the range or ranges
within the range.
In another embodiment, the method of use claims include various combinations of the
polymer components such as molecular weight, functional groups, monomer components, and
molar amounts of said components. In a further embodiment, the claimed methods of use
include combinations of the dependent claims. In a further embodiment, a range or equivalent
thereof of a particular component shall include the individual component(s) within the range or
ranges within the range.

CLAIMS
We claim:
1. A method of removing one or more metals from a medium contaimng these metals which
comprises the steps of: (a) treating said medium containing metals with a composition
comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine,
and wherein said acrylic-x has the following formula:
wherein X = OH and salts thereof or NHR2 and wherein R1 and R2 is H or an alkyl or
aryl group, wherein R is an alkyl or ary group, wherein the molecular weight of said
polymer is between 500 to 200,000, and wherein said polymer is modified to contain a
functional group capable of scavenging one or more compositions containing one or more
metals; and (b) collecting said treated metals.
2. The method of claim 1, wherein said functional group is a dithiocarbamate salt group and
wherein said polymer has between 5 to 100 mole % of said dithiocarbamate salt group.
3. The method of claim 1, wherein the acrylic-X is acrylic acid or salts thereof and the
alkylamine is PEHA or TEPA or DETA or TETA or EDA, and wherein the molar ratio
between acrylic-x and alkylamine is from 0.85 to 1.5; and wherein the molecular weight
of said polymer is from 1,500 to 8,000; and wherein the polymer is modified to contain
more than 55 mole percent dithiocarbamic acid or salts thereof.
4. The method of claim 1, wherein the acrylic-X is acrylamide and the alkylamine is PEHA
or TEPA or DETA or TETA or EDA, and wherein the molar ratio between acrylic-x and
alkylamine is from 0.85 to 1.5; and wherein the molecular weight of said polymer is from
1,500 to 8,000; and wherein the polymer is modified to contain more than 55 mole
percent dithiocarbamic acid or salts thereof.
5. The method of claim 1, further comprising an additional treatment of said process stream
with a complexing amount of a water soluble ethylene dichloride ammonia polymer
having a molecular weight of from 500 to 100,000 which contains 5 to 50 mole % of
dithiocarbamate salt groups to form a complex of these metals.
6. The method of claim 5 further comprising: applying an oxidizing agent to the flue gas;
optionally wherein said oxidizing agent oxidizes a target species at a temperature of
500°C or greater; optionally wherein said target species is elemental mercury or
derivatives thereof; and optionally wherein said oxidizing agent is at least one of the
following: a thermolabile molecular halogen, calcium bromide, or a halogen containing
compound.
A method of removing one or more metals from a medium containing these metals which
comprises the steps of: (a) treating said medium containing metals with a composition
comprising a polymer derived from at least two monomers: acrylic-x and an alkylamine,
wherein said acrylic-x has the following formula:
wherein X = OR and wherein R is an alkyl or aryl group, wherein R is H or an alkyl or
an aryl group, and wherein the molecular weight of said polymer is between 1,000 to
16,000, and wherein said polymer is modified to contain a functional group capable of
scavenging one or more compositions containing one or more metals; and collecting said
treated metals.
8. The method of claim 7, wherein said functional group is a dithiocarbamate salt group and
optionally wherein said polymer has between 5 to 100 mole % of said dithiocarbamate
salt group.
9. The method of claim 7, wherein the acrylic-X is an acrylic ester and the alkylamine is
PEHA or TEPA or DETA or TETA or EDA, and wherein the molar ratio between
acrylic-x and alkylamine is from 0.85 to 1.5; and wherein the molecular weight of said
polymer is from 1,500 to 8000; and wherein the polymer is modified to contain more than
55 mole percent dithiocarbamic acid or salts thereof.
10. The method of claim 7, wherein the metals are at least one of the following: copper,
nickel, zinc, lead, mercury, cadmium, silver, iron, manganese, palladium, platinum,
strontium, selenium, arsenic, cobalt and gold.
1. The method of claim 7, further comprising an additional treatment of said process stream
with a complexing amount of a water soluble ethylene dichloride ammonia polymer
having a molecular weight of from 500 to 100,000 which contains 5 to 50 mole % of
dithiocarbamate salt groups to form a complex of these metals.
1 . The method of claim 11 further comprising: applying an oxidizing agent to the flue gas;
optionally wherein said oxidizing agent oxides a target species at a temperature of 500°C
or greater; optionally wherein said target species is elemental mercury or derivatives
thereof; and optionally wherein said oxidizing agent is at least one of the following: a
thermolabile molecular halogen, calcium bromide, and a halogen containing compound.
13. The method of claim 11wherein said polymer treatment occurs at a temperature at or
below 300°C.
14. The method of claim 7, wherein the acrylic ester can be at least one of the following:
methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate, propyl
acrylate, and propyl methacrylate.