▎ 摘　　要

NOVELTY - A zwitterion-modified graphene oxide double-layer structure composite membrane comprises porous support base membrane and double-layer separation layer. The double-layer separation layer comprises graphene oxide layer and zwitterionic layer. A graphene oxide layer is formed on the surface of the porous support base membrane, and the zwitterionic layer is constructed on the surface of the graphene oxide layer. A dopamine component is also included between the double-layer structures to strengthen interlayer interfacial compatibility. USE - Zwitterion-modified graphene oxide double-layer structure composite membrane for dehydration of pervaporation ethanol-water or/and butanol-water system (all claimed). ADVANTAGE - The zwitterion layer can improve the hydrophilicity of the surface of the membrane, strengthen the dissolution process of the surface of the membrane on water molecules and improve the separation selectivity. The lower graphene oxide layer is used as a rapid mass transfer channel of molecules, so that the diffusion process of the molecules is enhanced, and the permeability of the membrane is improved. The dopamine can improve the compatibility of the interlayer interface which ensures the stability of the membrane structure. The composite membrane prepared by the method can ensure the pervaporation process of preferential dissolution and preferential diffusion of water molecules, obtain high permeation flux and high separation factor, and maintain good long-term operation stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the zwitterion-modified graphene oxide double-layer structure composite membrane, which involves dispersing graphene oxide into deionized water, stirring and ultrasonic processing to form a graphene oxide dispersion liquid, fixing porous support base membrane, depositing the graphene oxide dispersion liquid on the surface of the support base membrane in a vacuum-assisted suction filtration mode, heat treating to obtain a graphene oxide composite membrane, dissolving tris (hydroxymethyl) aminomethane in deionized water, uniformly stirring, adjusting the pH value of the solution to obtain a tris buffer solution with the concentration of 20-60 mM, dissolving a zwitterionic material in the tris buffer solution, uniformly stirring, adding dopamine hydrochloride, stirring and dissolving to obtain a mixed solution, placing the graphene oxide composite membrane into the solution, enabling the graphene oxide membrane surface to contact the solution, depositing in an oscillator, washing with deionized water after deposition is finished, and drying. The mass ratio of the zwitterion material to the dopamine hydrochloride is 0.5-20:1.