▎ 摘　　要

NOVELTY - Nano composite filter membrane comprises alumina nanoceramic membrane and graphene layer disposed on at least one surface of the alumina nanoceramic membrane and pore size of the nano composite filtration membrane is 0.6 nm. USE - The nano composite filter membrane is useful for separating salt and water (claimed). ADVANTAGE - The nano composite filter membrane has better salt separation effect, large flux, high rejection rate and does not block membrane pore size, retains salt molecules, is resistant to pollution and easy to clean and preparation method is simple and convenient. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing filter membrane, comprising (i) setting alumina nano ceramic film, (ii) preparing graphene solution and forming graphene coating on the alumina nanoceramic film by a spin coating method, and (iii) drying alumina nanoceramic film provided with graphene coating under vacuum; (2) filter, prepared by above mentioned nano composite filtration membrane; and (3) separating salt and water, comprising passing brine (e.g. seawater) through the filter.