Water purification

Patent metadata

Field	Value
Publication number	US-2016280563-A1
Application number	US-201415037143-A
Country	US
Kind code	A1
Filing date	Nov 20, 2014
Priority date	Nov 21, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

This invention relates to methods of purifying water using graphene oxide laminates which are formed from stacks of individual graphene oxide flakes which may be predominantly monolayer thick. The graphene oxide laminates may act as membrans which exclude large solutes i.e. with a hydration radius above about 4.5 Å or they may act as sorbents to absorb solutes having a hydration radius less than about 4.7 Å.

First claim

1 . A method of reducing the amount of one or more solutes in an aqueous mixture to produce a liquid depleted in said solutes; the method comprising:
(a) contacting a first face of a graphene oxide laminate membrane with the aqueous mixture comprising the one or more solutes; and (b) recovering the liquid from or downstream from a second face of the membrane; wherein the graphene oxide laminate membrane has a thickness greater than 100 nm and wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.2:1.0 to 0.5:1.0.

2 . A method of claim 1 , wherein the method is method of selectively reducing the amount of a first set of one or more solutes in an aqueous mixture without significantly reducing the amount of a second set of one or more solutes in the aqueous mixture to produce a liquid depleted in said first set of solutes but not depleted in said second set of solutes, wherein the or each solute of the first set has a radius of hydration greater than 4.5 Å and the or each solute of the second set has a radius of hydration less than 4.5 Å.

3 . The method of claim 1 , wherein no electrical potential is applied across the membrane.

4 . A method of claim 1 , wherein the method is continuous.

5 . A fluid filtration device comprising a graphene oxide laminate membrane having a thickness greater than 100 nm and wherein the graphene oxide flakes from which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.2:1.0 to 0.5:1.0.

6 . A method of claim 1 , wherein the graphene oxide laminate membrane is supported on a porous material.

7 . A method of claim 1 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.3:1.0 to 0.4:1.0.

8 . A method of reducing the amount of one or more solutes in an aqueous mixture to produce a liquid depleted in said solutes; the method comprising:
(a) contacting the aqueous mixture with a sorbent comprising a graphene oxide laminate membrane; and (b) separating the sorbent from the liquid.

9 . A method of claim 8 , wherein the method is method of selectively reducing the amount of a first set of one or more solutes in an aqueous mixture without significantly reducing the amount of a second set of one or more solutes in the aqueous mixture to produce a liquid depleted in said first set of solutes but not depleted in said second set of solutes, wherein the or each solute of the first set has a radius of hydration less than 4.5 Å and the or each solute of the second set has a radius of hydration greater than 4.7 Å.

10 . A method of claim 8 , the method further comprising removing the one or more solutes from the sorbent.

11 . A method of claim 8 , wherein the graphene oxide laminate membrane is supported on a flexible porous support.

12 . A method of claim 8 , wherein the pH of the aqueous mixture is between 6 and 13.

13 . A sorbent comprising a graphene oxide laminate membrane supported on a flexible porous support.

14 . A method of claim 8 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.2:1.0 to 0.5:1.0.

15 . A method of claim 8 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.3:1.0 to 0.4:1.0.

16 . A method of claim 8 , wherein the graphene oxide laminate membrane has a thickness greater than 100 nm.

17 . A device of claim 5 , wherein the graphene oxide laminate membrane is supported on a porous material.

18 . A device of claim 5 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.3:1.0 to 0.4:1.0.

19 . A sorbent of claim 13 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.2:1.0 to 0.5:1.0.

20 . A sorbent of claim 19 , wherein the graphene oxide flakes of which the laminate is comprised have an average oxygen:carbon weight ratio in the range of from 0.3:1.0 to 0.4:1.0.

21 . A sorbent of claim 19 , wherein the graphene oxide laminate membrane has a thickness greater than 100 nm.

Assignees

• Univ Manchester

Inventors

• Raveendran-Nair Rahul
• Joshi Rakesh K
• Geim Andre

Classifications

• B01J20/28033

  Membrane, sheet, cloth, pad, lamellar or mat · CPC title

• B01D2325/04

  Characteristic thickness · CPC title

• C01B32/23

  Oxidation · CPC title

• B01J20/321

  consisting of a polymer obtained by reactions involving only carbon to carbon unsaturated bonds · CPC title

• B01J20/3212

  consisting of a polymer obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds · CPC title