Method of heavy metal removal from water streams

Patent metadata

Field	Value
Publication number	US-9328003-B2
Application number	US-201314076488-A
Country	US
Kind code	B2
Filing date	Nov 11, 2013
Priority date	Sep 7, 2006
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

The invention provides methods and compositions for separating metals from a liquid medium, the method uses a copolymer derived from at least two monomers: acrylic-x and an alkylamine, wherein said polymer is modified to contain a functional group capable of scavenging one or more compositions containing one or more metals are disclosed. The treated liquid is then passed through a filtration system. The scavenging effect of the combination of the treatment with the filtration is unexpectedly greater than the sum of its parts.

First claim

The invention claimed is:

1. A method of removing one or more metals from a medium containing said metals which comprises the steps of:
(a) treating said medium containing metals with a composition comprising a copolymer derived from at least two monomers: acrylic-x and an alkylamine,
(b) passing the treated medium through a filter, and
(c) collecting said metals;

wherein said acrylic-x has the following formula:

wherein X is OH and salts thereof or NHR 2 and wherein R 1 and R 2 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 said medium containing one or more metals.

2. The method of claim 1 , wherein the filter is selected from the group consisting of: a sand filter, paper, and any combination thereof.

3. The method of claim 1 , wherein the filter is selected from the group consisting of: ultrafiltration, nanofiltration, microfiltration, reverse flow filtration, submerged membrane filtration, reverse osmosis, and any combination thereof.

4. 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.

5. The method of claim 1 , wherein the acrylic-x is acrylic acid or salts thereof and the alkylamine is pentaethylenehexamine or tetraethylenepetamine or diethylenetriamine or triethylenetetraamine or ethylenediamine, 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 20 mole percent dithiocarbamic acid or salts thereof.

6. The method of claim 1 , wherein the acrylic-x is acrylamide and the alkylamine is pentaethylenehexamine or tetraethylenepetamine or diethylenetriamine or triethylenetetraamine or ethylenediamine, 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 20 mole percent dithiocarbamic acid or salts thereof.

7. The method of claim 1 , wherein said medium is a process stream containing water.

8. The method of claim 1 , wherein the metals are selected from the group consisting of: copper, nickel, zinc, lead, mercury, cadmium, silver, iron, manganese, palladium, platinum, strontium, selenium, arsenic, cobalt, gold, and any combination thereof.

9. 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 80 mole % of dithiocarbamate salt groups to form a complex of these metals.

10. The method of claim 1 wherein said polymer treatment occurs at a temperature at or below 300° C.

11. The method of claim 1 wherein the copolymer further comprises a fluorescent group.

12. The method of claim 1 , wherein said medium is treated with oxidant first before treatment with scavenging polymer.

13. The method of claim 1 , wherein said medium is pH adjusted first before treatment with scavenging polymer.

14. The method of claim 1 , wherein said medium is treated with another coagulant before, together or after treatment with scavenging polymer.

15. A method of removing one or more metals from water containing said metals which comprises the steps of:
(a) treating said water containing metals with a composition comprising a copolymer derived from at least two monomers: acrylic-x and an alkylamine,
(b) passing the treated water through a filter, and
(c) collecting said metals;

wherein said acrylic-x has the following formula:

wherein X is OH and salts thereof or NHR 2 and wherein R 1 and R 2 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 said medium containing one or more metals;
and wherein mixing conditions between the one or more metals and the composition are such that they form agglomerations of copolymer-metal complexes having a size distribution such that a majority of the complexes could not be collected but for the filter.

16. The method of claim 15 , wherein the filter comprises a membrane through which the water passes and the mixing occurs only during a duration of time that is too short for agglomerations of copolymer-metal complexes to form which are larger than the pore size of the membrane.

Assignees

• Nalco Co

Inventors

• Musale Deepak A
• Schwarz Daniel E
• Zinn Paul J
• Keiser Bruce A
• Shah Jitendra T

Classifications

• B01D61/147

  Microfiltration · CPC title

• C02F11/12

  by de-watering, drying or thickening · CPC title

• C02F1/66

  by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58) · CPC title

• B01D2317/08

  Use of membrane modules of different kinds · CPC title

• B01D2321/04

  Backflushing · CPC title