Method for reducing arsenic concentration in aqueous solutions

Patent metadata

Field	Value
Publication number	US-2017113949-A1
Application number	US-201515317233-A
Country	US
Kind code	A1
Filing date	Jun 12, 2015
Priority date	Jun 13, 2014
Publication date	Apr 27, 2017
Grant date	—

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

1 . A method of reducing the arsenic concentration in an aqueous solution that comprises undesired 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;
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 . (canceled)

3 . A method according to claim 1 , wherein the negatively charged counter ion is NO 3 − , ClO 4 − , AcO − , PF 6 − , BF 4 − , Cl − , BPh 4 − or Br.

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

5 . A method according to claim 4 , wherein the method reduces the concentration of undesired arsenic in the aqueous solution to less than about 5 μg L −1 .

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

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

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

9 . A method according to claim 8 , 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.

10 . 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.

11 . A method according to claim 1 , wherein the initial pH of the aqueous solution is from about 1 to about 10.

12 . A method according to claim 11 , wherein the initial pH of the aqueous solution is from about 5 to about 10.

13 . A method according to claim 12 , wherein the initial pH is about 7.

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

15 . A method according to claim 14 , 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.

16 . A method according to claim 15 , wherein the solution is of a halide salt of an alkali metal.

17 . A method according to claim 16 , wherein the solution is a NaCl or NaOAc solution.

18 . A method-according to claim 1 and comprising the steps of:
(i) contacting an aqueous solution comprising undesired arsenic with a complex of Formula I to form a complex of Formula I to which arsenic is bound; and
(ii) 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.

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

20 . 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.

21 . A method according to claim 1 , comprising the additional step of reacting the aqueous solution comprising undesired 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.

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

23 . A method according to claim 22 , wherein the additional absorbent is an iron oxide absorbent.

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

25 . 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.

26 . A complex according to claim 25 , wherein the solid support is a polystyrene based resin.

27 . A complex according to claim 26 , 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.

28 . A filtration device comprising a complex of Formula I as defined in claim 1 .

29 . A filtration device according to claim 28 , wherein the device is a flat bed or a column.

30 . A filtration device according to claim 28 which further comprises an additional absorbent.

31 . A filtration device according to claim 30 wherein the additional absorbent is an iron oxide absorbent.

32 . (canceled)

33 . (canceled)

34 . (canceled)

Assignees

• Imp Innovations Ltd

Inventors

• Moffat Christopher
• Compte Ramon Vilar
• Weiss Dominik

Classifications

• C02F1/288

  using composite sorbents, e.g. coated, impregnated, multi-layered · CPC title

• B01J20/223

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

• B01J20/3219

  involving a particular spacer or linking group, e.g. for attaching an active group · CPC title

• B01J20/3425

  of sorbents or filter aids comprising organic materials · CPC title

• B01J20/3242

  Layers with a functional group, e.g. an affinity material, a ligand, a reactant or a complexing group · CPC title