▎ 摘　　要

NOVELTY - Preparing graphene oxide modified polyamide complex nanofiltration membrane comprises e.g. dissolving polyamide in N,N-dimethylformamide, preparing into casting solution containing 20-25% polyamide, stirring at 65-70 degrees C, degassing at constant temperature, cooling to room temperature, pouring casting solution onto glass plate to scrape the film, placing in water bath at 25-28 degrees C to form film, immersing in deionized water to obtain polyamide ultrafiltration base membrane, adding alkaline solution into the graphene oxide solution, dispersing evenly, adjusting pH of the solution to neutral with hydrochloric acid, centrifuging, washing with deionized water, dissolving product in deionized water, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and tetraethylene pentamine, performing grafting reaction for 10-12 hours, performing dialysis to obtain aqueous solution of graphitized graphene oxide, and adding crosslinking agent in aqueous solution of graphitized graphene oxide. USE - The method is useful for preparing graphene oxide modified polyamide complex nanofiltration membrane. ADVANTAGE - The nanofiltration membrane: has high hydrophilicity due to large amount of free carboxy groups and hydroxy groups on the surface of the film, good compactness; and improves salt rejection rate which improves flux and desalination effect. The method is suitable for large-scale industrial production. DETAILED DESCRIPTION - Preparing graphene oxide modified polyamide complex nanofiltration membrane comprises (i) dissolving polyamide in N,N-dimethylformamide, preparing into casting solution containing 20-25% polyamide, stirring at 65-70 degrees C, degassing at constant temperature, cooling to room temperature, pouring casting solution onto glass plate to scrape the film, placing in water bath at 25-28 degrees C to form film, and immersing in deionized water to obtain polyamide ultrafiltration base membrane, (ii) adding alkaline solution into the graphene oxide solution, dispersing evenly, adjusting pH of the solution to neutral with hydrochloric acid, centrifuging, washing with deionized water, dissolving product in deionized water, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and tetraethylene pentamine, performing grafting reaction for 10-12 hours, and performing dialysis to obtain aqueous solution of graphitized graphene oxide, (iii) adding crosslinking agent into the aqueous solution of the graphitized graphene oxide, and adjusting pH by alkaline solution to obtain an aminated graphene oxide cross-linking solution, and (iv) providing polyamide ultrafiltration base membrane, coating aminated graphene oxide cross-linking solution on base membrane by surface coating method, and coating polyamide ultrafiltration membrane casting solution to obtain graphene oxide modified polyamide complex nanofiltration membrane. An INDEPENDENT CLAIM is also included for graphene oxide modified polyamide complex nanofiltration membrane comprising two upper and lower polyamide layers sandwiching an aminated graphene oxide sheet.