▎ 摘　　要

NOVELTY - Processing of nano-filtration membrane involves providing a porous substrate layer on a surface of a polymer-based ultrafiltration membrane, subjecting resultant to ion treatment by soaking resultant in a solution comprising 0.05-0.2 mol/L sodium polystyrene sulfonate, removing, washing using pure water, soaking the treated film in poly(diallyldimethylammonium chloride) solution, removing, washing using pure water, obtaining an ion-treated membrane, soaking in graphene oxide solution, drying, coating polyvinyl alcohol solution on a surface of resultant film, and drying. USE - Processing of nano-filtration membrane (claimed). ADVANTAGE - The method enables efficient preparation of nano-filtration membrane having high performance. DETAILED DESCRIPTION - Processing of nano-filtration membrane involves providing a porous substrate layer on a surface of a polymer-based ultrafiltration membrane, subjecting resultant to ion treatment by soaking resultant in a solution comprising 0.05-0.2 mol/L sodium polystyrene sulfonate and having pH of 3-5, for 25-30 minutes, removing, washing using pure water, soaking the treated film in poly(diallyldimethylammonium chloride) solution having concentration of 0.05-0.2 mol/L and pH of 4-6, for 25-30 minutes, removing, washing using pure water, obtaining an ion-treated membrane, adding 98 %mass sulfuric acid to an expandable graphite, adding potassium permanganate, stirring, placing resultant in water bath, heat-preserving at 45-50 degrees C for 0.5-1.5 hours, adding deionized water, processing at 95-100 degrees C for 25-30 minutes, cooling, adding hydrogen peroxide solution having concentration of 25%, filtering, washing using deionized water, drying at 65-75 degrees C, obtaining oxidized graphene powder, dispersing resultant in a polar solvent, centrifuging, obtaining graphene oxide solution, soaking the ion-treated membrane in resultant solution at 0.05-0.5 MPa, oven-drying resultant product, coating polyvinyl alcohol solution having concentration of 11-15 %mass on a surface of resultant film, and vacuum-drying.