▎ 摘　　要

NOVELTY - Modified graphene comprises graphene containing organic branched chain, and the organic branched chain is connected to carbon skeleton using sulfur bond. USE - The modified graphene used in graphene composite filter membrane for seawater desalination (claimed). ADVANTAGE - The modified graphene realizes the graphene inseawater desalination membrane separation, solves the problem of water leakage and salt leakage in direct use of graphene pressure filtration to form membranes, and ensures low-dimensional and hydrophobic inorganic material. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing modified graphene, involving after uniformly mixing dispersion liquid of graphene with fluorine-containing mercaptan, performing olefin-thiol click reaction under action of initiator, and performing solid-liquid separation to obtain modified graphene; (2) a graphene composite filter membrane comprising porous substrate wrapped with modified graphene layer; and (3) a method for preparing graphene composite filter membrane, involving dissolving modified graphene in solvent, and depositing on surface of porous substrate using press-filtration additive deposition method to obtain graphene composite filter membrane.