GRAPHENE OXIDE MEMBRANES AND METHODS RELATED THERETO

• US 20170312695A1
• Filed: 11/19/2015
• Published: 11/02/2017
• Est. Priority Date: 11/19/2014
• Status: Active Grant

• Current Assignee: Monash University
• Original Assignee: Monash University
• Inventors: Majumder, Mainak, Akbarivakilabadi, Abozar
• Granted Patent: US 10,835,873 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2323/06 Specific viscosities of materials involved
• CPC Class Codes: B01D 2323/10 Specific pressure applied
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2325/50 Membrane in gel form
• CPC Class Codes: B01D 61/027 Nanofiltration
• CPC Class Codes: B01D 67/0048 by sol-gel transition
• CPC Class Codes: B01D 67/0069 by deposition from the liquid phase, e.g. electrochemical deposition B01D67/0046 takes precedence
• CPC Class Codes: B01D 67/00793 Dispersing a component, e.g. as particles or powder, in another component
• CPC Class Codes: B01D 67/0083 Thermal after-treatment
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 69/107 Organic support material
• CPC Class Codes: B01D 69/108 Inorganic support material
• CPC Class Codes: B01D 69/148 Organic/inorganic mixed matrix membranes
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/0211 Graphene or derivates thereof
• CPC Class Codes: B01D 71/024 Oxides
• CPC Class Codes: B01D 71/381 Polyvinylalcohol
• CPC Class Codes: B01D 71/401 Polymers based on the polymerisation of acrylic acid, e.g. polyacrylate
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 32/192 starting from graphitic oxides
• CPC Class Codes: C01B 32/198 : Graphene oxide
• CPC Class Codes: C01B 32/23 : Oxidation
• CPC Class Codes: C09K 19/52 : characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
• CPC Class Codes: C09K 2019/521 : Inorganic solid particles

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.

Claims

1. A method for concentrating a stabilized solution of graphene oxide comprising a continuous phase and having an initial graphene and/or graphene oxide concentration, the method comprising:

adding an absorbent material to the solution; and

absorbing at least a portion of the continuous phase from the solution with the absorbent material to form a solution having a graphene oxide concentration that is greater than the initial graphene oxide concentration.

2. The method of claim 1, further comprising the step of separating the absorbent material and the solution after the absorbing step.

3. The method of claim 1, wherein the continuous phase is water.

4. The method of claim 3, wherein the absorbent material is a hydrogel material.

5. The method of claim 4, wherein the hydrogel material is in the form of hydrogel beads, and the step of adding the absorbent material comprises adding a plurality of hydrogel beads.

6. The method of claim 5, wherein the step of adding a plurality of hydrogel beads comprises adding the hydrogel beads over a period of time.

7. The method of claim 1, wherein the final graphene oxide concentration is greater than 15 mg/L.

8. The method of claim 1, wherein the absorbing step is conducted for a time of up to 1 hour.

9. A method of forming a film of a stabilized solution of graphene oxide on a substrate surface, the method comprising:

applying an amount of the solution of graphene oxide to the substrate surface;

drawing the solution through a channel defined by two opposing surfaces having a gap there between at a shear rate, wherein a first opposing surface of the channel is the substrate surface; and

forming a film of the solution having a thickness corresponding to a length of the gap.

10. The method of claim 9, wherein the concentration of the solution of graphene oxide is greater than 15 mg/mL.

11. The method of claim 9, wherein the step of drawing the solution through the channel applies a shear rate of from about 1000 to about 10,000 per second.

12. The method of claim 9, 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.

13. The method of claim 9, wherein the step of drawing the solution through the channel comprises moving the two opposing surfaces relative to one another.

14. The method of claim 9, wherein the substrate is a porous substrate selected from the group consisting of polymers, metals, and ceramics.

15. The method of claim 14, wherein the substrate has pore sizes in the range of from about 20 nm to about 1000 nm.

16. The method of claim 9, wherein the method further comprises treating the film to remove at least some functional groups that are present on the film.

17. The method of claim 16, 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.

18. The method of claim 16, wherein the step of treating the film comprises physical treatment with plasma, ion-beams, heat, UV light, or a combination thereof.

19. A graphene oxide film or a reduced graphene oxide film formed according to the method of claim 9.

20. A membrane for a membrane separation process, comprising the graphene oxide film or reduced graphene oxide film of claim 19.

21. A graphene oxide membrane comprising a graphene oxide layer on a support layer, the graphene oxide layer comprising aligned discotic graphene oxide particles.