Graphene oxide nanocomposite membrane for gas separation, reduced graphene oxide nanocomposite membrane and method for manufacturing the same
The present invention relates to a technology for manufacturing a nanocomposite membrane comprising a graphene oxide coating layer with a thickness of 1 nm to 50 nm, which is formed on various supports and has nanopores, and a reduced graphene oxide nanocomposite membrane, and applying the membranes to gas separation. The graphene oxide nanocomposite membrane for gas separation of the present invention has excellent gas permeability and selectivity at the same time, and especially, excellent hydrogen gas permeability and hydrogen gas selectivity compared with carbon dioxide, and the reduced graphene oxide nanocomposite membrane has remarkably enhanced hydrogen gas permeability and hydrogen gas selectivity compared with carbon dioxide, and thus the membranes are applicable as a gas separation membrane in an industrial field involving a hydrogen separation process. Furthermore, a graphene oxide nanocomposite membrane for gas separation can be provided, in which strong binding force between a support and a graphene oxide coating layer is induced by modifying surfaces of various supports and thus the graphene oxide coating layer is not easily delaminated.
1. A graphene oxide nanocomposite membrane for gas separation comprising:
a support; and
a graphene oxide coating layer with a thickness of 1 nm to 50 nm disposed on the support and having nanopores, wherein the support is surface-doped with nitrogen and has a contact angle of 10 to 50°, a surface roughness of 0.1 to 5.0 nm and a surface charge of −20 to +20 mV.
2. The graphene oxide nanocomposite membrane for gas separation according to claim 1 , wherein the support is a porous polymer support, which is selected form the group consisting of polysulfone, polyether sulfone, polyimide, polyether imide, polyamide, polyacrylonitrile, cellulose acetate, cellulose triacetate, and polyvinylidene fluoride.
3. The graphene oxide nanocomposite membrane for gas separation according to claim 1 , wherein the porous polymer support has a pore size of 10 nm to 500 nm.
4. The graphene oxide nanocomposite membrane for gas separation according to claim 1 , wherein the graphene oxide has a size of 0.1 μm to 5 μm.
5. The graphene oxide nanocomposite membrane for gas separation according to claim 1 , wherein the nanopores have a mean diameter of 0.5 nm to 2.0 nm.
6. A method of manufacturing a graphene oxide nanocomposite membrane for gas separation comprising:
i) preparing a dispersion of graphene oxide in distilled water;
ii) treating the dispersion with an ultrasonic grinder for 0.1 to 6 hours; and
iii) coating a support with the ultrasonicated solution to form a coating layer.
7. The method according to claim 6 , further comprising treating the support with plasma and doping with nitrogen before forming the coating layer.
8. The method according to claim 6 , wherein the dispersion is a 0.01 to 0.5 wt % aqueous graphene oxide solution having a pH adjusted to 10.0 using a 1M aqueous sodium hydroxide solution.
9. The method according to claim 6 , wherein the coating is carried out by any one method selected from the group consisting of direct evaporation, transfer, spin coating and spray coating.
10. The method according to claim 9 , wherein the spin coating is conducted three to ten times.