Graphene oxide membranes and methods related thereto

Patent metadata

Field	Value
Publication number	US-10835873-B2
Application number	US-201515525923-A
Country	US
Kind code	B2
Filing date	Nov 19, 2015
Priority date	Nov 19, 2014
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

An improved method for concentrating dispersions of graphene oxide, coating a substrate with a layer of a graphene oxide solution, and producing a supported graphene membrane stabilised by controlled deoxygenation; and graphene-based membranes that demonstrate ultra-fast water transport, precise molecular sieving of gas and solvated molecules, and which show great promise as novel separation platforms.

First claim

What is claimed is:

1. A method of forming an asymmetric graphene oxide membrane suitable for the separation of molecules with a molecular weight in the range of 200-800 Da in a membrane separation process, wherein the membrane is prepared by a method of forming a film of a stabilized solution of discotic nematic graphene oxide on a substrate surface, the method comprising:
applying an amount of the solution of discotic graphene oxide in a nematic crystalline state with a graphene oxide concentration of 16 mg/mL or greater to the substrate surface;
drawing the solution through a rectangular channel defined by two opposing surfaces having a gap there between at a shear rate of from 1,000 to 10,000 per second determined according to the Navier-Stokes equation assuming that fluid flow is Newtonian, wherein a first opposing surface of the channel is the substrate surface; and
forming a film of aligned discotic graphene oxide having a thickness corresponding to a length of the gap;
wherein the substrate is a porous substrate selected from the group consisting of polymers, metals, and ceramics, having pore sizes in the range of from 20 nm to 1000 nm; and
wherein a second opposing surface is an applicator surface of a coating apparatus selected from the group consisting of: a rod coater, a roll coater, a knife coater, a flexible applicator, a curtain coater, and a gravure coater; and the step of drawing the solution through the channel comprises moving the two opposing surfaces relative to one another.

2. The method of claim 1 , wherein the graphene oxide concentration is 20 mg/mL or greater.

3. The method of claim 1 , wherein the method further comprises treating the film to remove at least some functional groups that are present on the film.

4. The method of claim 3 , wherein the step of treating the film comprises chemical treatment with a compound selected from the group consisting of: hydrazine, sodium borohydrate, citrates, NaOH, KOH, or a combination thereof to form a reduced graphene oxide film.

5. The method of claim 3 , wherein the step of treating the film comprises physical treatment with plasma, ion-beams, heat, UV light, or a combination thereof.

6. The method of claim 1 , wherein the solution of discotic graphene oxide in a nematic crystalline state with a graphene oxide concentration of 16 mg/mL or greater is obtained by concentrating a more dilute solution of the discotic graphene oxide by mixing the more dilute solution with hydrogel beads and separating the hydrogel beads from the suspension.

Assignees

• Univ Monash

Inventors

• Majumder Mainak
• Akbarivakilabadi Abozar

Classifications

• B01D71/401

  Polymers based on the polymerisation of acrylic acid, e.g. polyacrylate · CPC title

• B01D69/107

  Organic support material · CPC title

• B01D71/0211

  Graphene or derivates thereof · CPC title

• B01D71/02

  Inorganic material · CPC title

• B01D69/108

  Inorganic support material · CPC title