GRAPHENE BASED FILTER

• US 20130270188A1
• Filed: 03/15/2013
• Published: 10/17/2013
• Est. Priority Date: 03/15/2012
• Status: Active Grant

• Current Assignee: King Fahd University Of Petroleum And Minerals, Massachusetts Institute of Technology
• Original Assignee: King Fahd University Of Petroleum And Minerals, Massachusetts Institute of Technology
• Inventors: Karnik, Rohit N., Laoui, Tahar, O'Hern, Sean C., Boutilier, Michael S.H., Stewart, Cameron A., Au, Harold S., Hadjiconstantinou, Nicolas G., Atieh, Muataz A.
• Granted Patent: US 11,135,546 B2
• Time in Patent Office: Days
• US Class Current: 210/650
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 67/0062 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/021 Carbon
• CPC Class Codes: B01D 71/0211 Graphene or derivates thereof
• CPC Class Codes: B01D 71/50 Polycarbonates
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: G01N 15/082 Investigating permeability by forcing a fluid through a sample
• CPC Class Codes: G01N 2015/084 Testing filters

Abstract

Two-dimensional material based filters, their method of manufacture, and their use are disclosed. The filters may include at least one active layer disposed on a porous substrate. The at least one active layer may include intrinsic and/or intentional formed pores. In some embodiments, the flow resistance of the porous substrate may be selected to limit flow through defects and intrinsic pores in the at least one active layer.

Claims

1. A filtration membrane comprising:

a porous substrate;

at least one active layer disposed on the porous substrate, wherein the at least one active layer includes pores, wherein a flow resistance of the porous substrate is less than approximately ten times a flow resistance of the at least one active layer.

2. The filtration membrane of claim 1, wherein the at least one active layer comprises at least one of graphene and graphene oxide.

3. The filtration membrane of claim 1, wherein the flow resistance of the porous substrate is greater than approximately 0.0001 times the flow resistance of the at least one active layer.

4. The filtration membrane of claim 1 wherein the flow resistance of the porous substrate is greater than approximately 0.05 times the flow resistance of the at least one active layer.

5. The filtration membrane of claim 1 wherein the flow resistance of the porous substrate is less than approximately one times the flow resistance of the at least one active layer.

6. The filtration membrane of claim 1 wherein the pores are sized to provide selectivity relative to a desired liquid or gas.

7. The filtration membrane of claim 1 wherein the porous substrate comprises at least one of a polymer, a ceramic, and a metal.

8. The filtration membrane of claim 1, wherein the porous substrate comprises a filtration membrane.

9. The filtration membrane of claim 8, wherein the filtration membrane is selected from the group consisting of a nanofiltration membrane, a reverse osmosis membrane, an ultrafiltration membrane, and a brackish water filtration membrane.

10. The filtration membrane of claim 1, wherein the at least one active layer is functionalized.

11. The filtration membrane of claim 10, wherein the at least one active layer is functionalized with at least one of a polymer, a chelating agent, and a macrocycle.

12. A filtration membrane comprising:

a porous substrate;

a first active layer disposed on the porous substrate;

a second active layer disposed on the first active layer; and

a plurality of pores formed in the first and second active layers, wherein the plurality of pores pass through both the first active layer and the second active layer.

13. The filtration membrane of claim 12, wherein the first active layer and the second active layer comprise at least one of graphene and graphene oxide.

14. The filtration membrane of claim 12, wherein the second active layer covers a defect present in the first active layer.

15. The filtration membrane of claim 12, wherein the plurality of pores are sized to provide selectivity relative to a desired liquid or gas.

16. The filtration membrane of claim 12, wherein the porous substrate comprises at least one of a polymer, a ceramic, and a metal.

17. The filtration membrane of claim 12, wherein the porous substrate comprises a filtration membrane.

18. The filtration membrane of claim 17, wherein the filtration membrane is selected from the group consisting of a nanofiltration membrane, a reverse osmosis membrane, an ultrafiltration membrane, and a brackish water filtration membrane.

19. The filtration membrane of claim 12, wherein the first active layer is functionalized.

20. The filtration membrane of claim 19, wherein the first active layer is functionalized with at least one of a polymer, a chelating agent, and a macrocycle.

21. A method for producing a filtration membrane, the method comprising:

providing a first active layer;

forming defects in the first active layer;

selectively etching the defects to form pores of a selected size in the first active layer.

22. The method of claim 21, wherein the first active layer comprises at least one of graphene and graphene oxide.

23. The method of claim 21 further comprising bonding the first active layer to a porous substrate.

24. The method of claim 23 wherein bonding the first active layer to the porous substrate is performed prior to forming defects in the first active layer.

25. The method of claim 21 further comprising providing an independent second active layer disposed on the first active layer, and forming defects in the first active layer and the second active layer at the same time.

26. The method of claim 25 further comprising selectively etching the first active layer and the second active layer at the same time to form pores of a selected size through both the first and second active layers.

27. The method of claim 21, wherein a flow resistance of the porous substrate is less than approximately ten times a flow resistance of the first active layer.

28. The method of claim 21, wherein a flow resistance of the porous substrate is greater than approximately one times a flow resistance of the first active layer.

29. The method of claim 21, wherein the flow resistance of the porous substrate is less greater than approximately 0.0001 times the flow resistance of the first active layer.

30. The method of claim 21, wherein selectively etching the defects comprises etching the defects with at least one nitric acid, potassium permanganate, sulfuric acid, hydrogen plasma, and hydrogen peroxide.

31. The method of claim 21 wherein forming defects in the first active layer comprises at least one of ion bombarding the first active layer;

treating the first active layer with plasma;

doping the first active layer;

UV-ozone treating the first active layer;

chemical vapor depositing the active layer on a substrate comprising nanograins that inhibit graphene growth; and

chemical vapor depositing the active layer on a substrate sprayed with nanoparticles.

32. The method of claim 21 further comprising functionalizing the first active layer.

33. The method of claim 32, wherein the first active layer is functionalized with at least one of a polymer, a chelating agent, and a macrocycle.

34. A filtration membrane comprising:

an active layer comprising graphene or graphene oxide, wherein the H₂ permeability of the active layer is greater than approximately 10<sup>−

6</sup> mol/m²-s-Pa.

35. A filtration method, the method comprising:

providing an active layer;

providing a concentration of an occluding molecule; and

varying the concentration of the occluding molecule to vary a permeability of the active layer.

36. The filtration method of claim 35, wherein the active layer comprises at least one of graphene or graphene oxide