▎ 摘　　要

NOVELTY - Preparing nano-filtration membrane comprises (a) oxidizing polypropylene microporous film to make the surface hydroxylation, and performing oxidation treatment by aqueous solution comprising persulfate composite, (b) subjecting polyamide separation layer to interfacial reaction aggregate aqueous-phase solution and organic phase solution, (c) contacting the aqueous phase solution with alcohol-based additive and amine-based compound as aqueous phase monomer, (d) using acyl chloride compoiste as organic-phase monomer and (e) post-processing to obtain nano membrane, where the post-treatment comprises using carboxy activating agent to process. USE - The method is useful for water treatment, medicine, food, biological purification, energy and chemical industry, sewage treatment, sea water desalting and cross-region water adjusting measures. ADVANTAGE - The method is simple, easy to operate, no need to improve the existing device, the operation cost is effective, the nanofiltration membrane prepared by has thin thickness, which can bring higher single membrane element effective filter area, in the water treatment process, has high flux and excellent separation performance (separation of salt ions and so on), and the performance is stable in long-term operation process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for nanofiltration membrane prepared by the above-mentioned preparation method.