▎ 摘　　要

NOVELTY - A composite nanofiltration membrane comprises graphene oxide and substrate. USE - Composite nanofiltration membrane used for desalination treatment, biomedicine and water treatment. ADVANTAGE - The method is nontoxic, and has simple operation, mild reaction conditions, and no pollution. The membrane has certain nanofiltration performance for the four salts, and very good practical value and potential value. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the membrane comprising preparing graphene oxide film through Langmuir-Blodgett technique, transferring to substrate, and repeatedly soaking and taking out.