Ultrathin, molecular-sieving graphene oxide membranes for separations along with their methods of formation and use
Methods for forming an ultrathin GO membrane are provided. The method can include: dispersing a single-layered graphene oxide powder in deionized water to form a single-layered graphene oxide dispersion; centrifuging the graphene oxide dispersion to remove aggregated graphene oxide material from the single-layered graphene oxide dispersion; thereafter, diluting the single-layered graphene oxide dispersion by about ten times or more through addition of deionized water to the graphene oxide dispersion; and thereafter, passing the single-layered graphene oxide dispersion through a substrate such that a graphene oxide membrane is formed on the substrate. Filtration membranes are also provided and can include: a graphene oxide membrane having a thickness of about 1.8 nm to about 180 nm, with the graphene oxide membrane comprises about 3 to about 30 layers of graphene oxide flakes.
1. A method of forming an ultrathin graphene oxide membrane, the method comprising:
dispersing a single-layered graphene oxide powder in deionized water to form a single-layered graphene oxide dispersion;
centrifuging the graphene oxide dispersion to remove aggregated graphene oxide material from the single-layered graphene oxide dispersion;
thereafter, diluting the single-layered graphene oxide dispersion by about ten times or more through addition of deionized water to the graphene oxide dispersion; and
thereafter, passing the single-layered graphene oxide dispersion through a substrate such that a graphene oxide membrane is formed on the substrate.
2. The method of claim 1 , further comprising:
after diluting the single-layered graphene oxide dispersion and prior to passing the single-layered graphene oxide dispersion through a substrate, sonicating the single-layered graphene oxide dispersion.
3. The method of claim 2 , wherein the single-layered graphene oxide dispersion is sonicated for greater than about 15 hours.
4. The method of claim 2 , wherein the single-layered graphene oxide dispersion is sonicated at about 5,000 rpm to about 15,000 rpm.
5. The method of claim 2 , wherein single-layered graphene oxide dispersion is sonicated at about 10,000 rpm.
6. The method of claim 1 , further comprising:
drying the graphene oxide membrane to remove any residue deionized water therefrom.
7. The method of claim 6 , wherein drying the graphene oxide membrane comprises storing the graphene oxide membrane in a vacuum desiccator.
8. The method of claim 1 , wherein the graphene oxide dispersion is centrifuged for about 30 minutes to about 40 minutes.
9. The method of claim 1 , herein the graphene oxide membrane comprises a plurality of single-layered graphene oxide flakes.
10. The method of claim 9 , wherein the graphene oxide membrane comprises about 3 to about 10 layers of single-layered graphene oxide graphene oxide flakes.
11. The method of claim 10 , wherein the single-layered graphene oxide flakes have a size up to about 500 nm.
12. The method of claim 1 , wherein the graphene oxide membrane has a thickness of about 1.8 nm to about 180 nm.
13. The method of claim 1 , wherein the graphene oxide membrane has a thickness of about 1.8 nm to about 20 nm.
14. The method of claim wherein the graphene oxide membrane has a thickness of about 1.8 nm to about 18 nm.
15. The method of claim 1 , wherein the substrate is supported on a filter, wherein the filter comprises pores that are larger than pores in the substrate.
16. The method of claim 15 , wherein the filter comprises pores having a pore size of about 20 nm to about 100 nm.
17. The method of claim 1 , wherein the graphene oxide membrane has an area of about 4 cm 2 or greater.
18. The method of claim 1 , wherein the substrate comprises an anodic aluminum oxide or a cellulose acetate.
19. The method of claim 1 , wherein the single-layered graphene oxide dispersion is diluted by about 20 times or more through addition of deionized water to the graphene oxide dispersion.
20. The method of claim 1 , wherein the single-layered graphene oxide dispersion is diluted by at least 100 times through addition of deionized water to the graphene oxide dispersion.
21. The method of claim 1 , wherein the single-layered graphene oxide dispersion has a concentration of about 0.2 mg/mL to about 0.4 mg/mL.
22. The method of claim 1 , wherein the single-layered graphene oxide dispersion has a concentration of about 0.3 mg/mL.