▎ 摘　　要

NOVELTY - Graphene oxide composite nanofiltration membrane, is claimed. The sandwich structure of graphene oxide composite nanofiltration membrane is formed by upper layer, middle layer and lower layer deposition; the upper layer and lower layer are both modified graphene oxide obtained by graphene oxide through cross-linking reaction, and surface of the modified graphene oxide is positively charged or non-polar; and the middle layer is graphene oxide. USE - The graphene oxide composite nanofiltration membrane is useful in water treatment (claimed). ADVANTAGE - The membrane: adopts idea of charge to change the charging properties of graphene oxide; has positive/negative/positive, which is similar to principle of homogenous repulsion and heterogeneous attraction in nature; enhances static electricity and screening performance and stability (when nanofiltration membranes handle solutions with charged properties); and adopts principle of polar action to change the polarity of graphene oxide, the cross-linking agent makes the graphene oxide carry lipophilic groups thus functional group is non-polar, and the membrane is non-polar/polar/non-polar, which can enhances service life of the membrane in aqueous solution and anti-pollution ability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing graphene oxide composite nanofiltration membrane, comprising (i) preparing and depositing lower layer modified graphene oxide, (ii) depositing middle layer of graphene oxide on surface of the modified graphene oxide in the lower layer of step (i), and (iii) depositing upper layer modified graphene oxide on the surface of the graphene oxide in the middle layer of step (ii) to obtain graphene oxide composite nanofiltration membrane.