▎ 摘　　要

NOVELTY - Composite nanofiltration membrane comprises support layer, a base layer and an oxide graphene layer. The base material is polyimide. The graphene oxide layer comprises one or more layers of graphene oxide. USE - Composite nanofiltration membrane used for liquid filtration, preferably for inorganic salt solution, organic solution or filtration of dye solution (all claimed) and used in polar solvents. ADVANTAGE - Composite nanofiltration membrane is produced in simple manner. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for producing composite nanofiltration membrane, which involves: (A) dissolving polyimide and polyethylene glycol in organic solvents, after defoaming treatment to obtain casting fluid; (B) coating casting liquid on the support layer, and then immersing in the water coagulation bath; (C) placing nanofiltration membrane in the crosslinking agent solution; (D) carrying the crosslinking reaction and after removing, the nanofiltration membrane is cleaned to obtain the modified nanofiltration membrane; and (E) applying oxidized graphene suspension to the surface of the modified nanofiltration membrane by pressurized filtration.