Method for reducing arsenic concentration in aqueous solutions

Patent metadata

Field	Value
Publication number	US-10479703-B2
Application number	US-201515317233-A
Country	US
Kind code	B2
Filing date	Jun 12, 2015
Priority date	Jun 13, 2014
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Method of reducing the arsenic concentration in an aqueous solution comprising undesired arsenic, which method comprises contacting the aqueous solution with a complex of Formula (I), (Formula (I)) wherein M1 and M2 are the same or different and are independently selected from V, Mn, Ga, Cu, Ni, Co, Fe or Zn; wherein a is 0, or 1, and b is 0, or 1, provided that a+b together must be at least 1; Q is a negatively charged counter ion; n is from 1 to 5; X1 is OH, O, SH or S; L1 is a group selected from —La1-C(O)NR—, —La2-C(O)OR—, —La3-NRC(O)—, La4-OC(O)—, La5-O— or La6-NRO—, wherein La1, La2, La3, La4, La5 and La6 are each C1-6 alkyl, optionally substituted, R is H or C1-6 alkyl optionally substituted; Linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units, a C1-16 polyamine chain or a C1-16 alkyl chain; Z is a solid support; L2 to L7 are independently C1-3 alkyl, optionally substituted; and Het1 to Het4 are independently 5 to 14 membered heteroaryl group having at least one N atom and optionally substituted.

First claim

The invention claimed is:

1. A method of reducing the arsenic concentration in an aqueous solution that comprises arsenic, which method comprises contacting the aqueous solution with a complex of Formula I,

wherein M 1 and M 2 are the same or different and are independently selected from V, Mn, Ga, Cu, Ni, Co, Fe or Zn; wherein a is 0, or 1, and b is 0, or 1, provided that a+b together must be at least 1;
Q is a negatively charged counter ion, wherein the negatively charged counter ion is NO 3 − , ClO 4 − , AcO − , PF 6 − , BF 4 − , Cl − , BPh 4 − or Br − ;
n is from 1 to 5;
X 1 is OH, O, SH or S;
L 1 is a group selected from -L a1 -C(O)NR—, -L a2 -C(O)OR—, -L a3 -NRC(O)—, L a4 -OC(O)—, L a5 -O— or L a6 -NRO—, wherein L a1 , L a2 , L a3 , L a4 , L a5 and L a6 are each C 1-6 alkyl, optionally substituted, R is H or C 1-6 alkyl optionally substituted;
Linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units, a C 1-16 polyamine chain or a C 1-16 alkyl chain;
Z is a solid support;
L 2 to L 7 are independently C 1-3 alkyl, optionally substituted; and
Het 1 to Het 4 are independently 5 to 14 membered heteroaryl group having at least one N atom and optionally substituted.

2. A method according to claim 1 , wherein the method reduces the concentration of arsenic in the aqueous solution to less than about 10 μg L −1 .

3. A method according to claim 2 , wherein the method reduces the concentration of arsenic in the aqueous solution to less than about 5 μg L −1 .

4. A method according to claim 3 , wherein the method reduces the concentration of arsenic in the aqueous solution to less than about 1 μg L −1 .

5. A method according to claim 1 , wherein the solid support is a polystyrene based resin.

6. A method according to claim 1 , wherein the Linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units.

7. A method according to claim 6 , wherein the solid support is a polystyrene based resin and the Linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units.

8. A method according to claim 1 , wherein one of M 1 or M 2 is zinc or both M 1 and M 2 are zinc.

9. A method according to claim 1 , wherein the initial pH of the aqueous solution prior to a point of contact with the complex of Formula I is from about 1 to about 10.

10. A method according to claim 9 , wherein the initial pH of the aqueous solution prior to a point of contact with the complex of Formula I is from about 5 to about 10.

11. A method according to claim 10 , wherein the initial pH prior to a point of contact with the complex of Formula I is about 7.

12. A method according to claim 1 , comprising the additional step of regenerating the complex of Formula I.

13. A method according to claim 12 , wherein the complex of Formula I is regenerated by contacting a complex of Formula I to which arsenic is bound with a solution of an alkali metal salt or an alkali earth metal salt having a pH of from about 7 to about 10.

14. A method according to claim 13 , wherein the solution is of a halide salt of an alkali metal.

15. A method according to claim 14 , wherein the complex of Formula I is regenerated by contacting the complex of Formula I to which arsenic is bound with a NaCl or NaOAc solution having a pH from about 7 to about 10.

16. A method according to claim 1 , further comprising the step of:
contacting the complex of Formula I to which arsenic is bound formed in step (i) with a NaCl or NaOAc solution having a pH of from about 7 to about 10.

17. A method according to claim 1 , comprising the additional step of filtering the aqueous solution comprising arsenic before contacting with a complex of Formula I.

18. A method according to claim 1 , comprising the additional step of filtering the aqueous solution comprising a complex of Formula I to which arsenic is bound after the aqueous solution has been contacted with a complex of Formula I.

19. A method according to claim 1 , comprising the additional step of reacting the aqueous solution comprising arsenic with an oxidising agent before contacting with a complex of Formula I, such that any arsenite present in the aqueous solution is oxidised to arsenate.

20. A method according to claim 1 , wherein the complex of formula I is used in combination with an additional absorbent.

21. A method according to claim 20 , wherein the additional absorbent is an iron oxide absorbent.

22. A method for providing potable water comprising a method according to claim 1 .

23. A complex of Formula IV,

wherein Z is a solid support and the linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units, a C 1-16 polyamine chain or a C 1-16 alkyl chain.

24. A complex according to claim 23 , wherein the solid support is a polystyrene based resin.

25. A complex according to claim 24 , wherein the solid support is a polystyrene based resin and the Linker is a polyethylene glycol (PEG) chain with from 1 to 10 repeating units.

Assignees

• Imperial Innovations Ltd
• Imperial College Innovations Ltd

Inventors

• Moffat Christopher
• Compte Ramon Vilar
• Weiss Dominik

Classifications

• B01J20/3208

  Polymeric carriers, supports or substrates · CPC title

• B01J20/3265

  with an organic functional group containing a metal, e.g. a metal affinity ligand · CPC title

• C02F1/62 Primary

  Heavy metal compounds · CPC title

• C02F1/285 Primary

  using synthetic organic sorbents · CPC title

• B01J20/223

  containing metals, e.g. organo-metallic compounds, coordination complexes · CPC title