▎ 摘　　要

NOVELTY - Preparation of composite nanofiltration membrane involves dispersing 2-15 g nano graphene powder into 10 mL N-methylpyrrolidone, preparing graphene dispersion, adding 80 wt.% N-methylpyrrolidone aqueous solution to the graphene dispersion, adding 0.026 mg methyl N-methylanthranilate, obtaining nano graphene dispersant, cooling to room temperature, mixing 0.2-3 wt.% nano graphene dispersant aqueous solution and 0.1-4.0 wt.% sodium dodecylbenzene sulfonate aqueous solution, and dispersing hydrophobic PTFE, immersing ethylene microporous membrane and drying, obtaining active nano graphene base film, immersing in 0.1-10.0 wt.% amine monomer aqueous solution, drying, obtaining intermediate film, immersing in 0.1-10.0 wt.% solution of an organic solvent of acid chloride monomers, drying, immersing in aqueous solution of an amine monomer, drying, immersing in 0.1-10.0 wt.% solution of organic solvent of acid chloride monomer, rinsing with deionized water, and drying. USE - Preparation of composite nanofiltration membrane. ADVANTAGE - The method is simple, and produces composite nanofiltration membrane with high strength and without requiring an additional support layer. The composite nanofiltration membrane utilizes the unique node-fibril microporous structure of the PTFE microporous membrane, which improves the bonding strength between the base membrane and the nanofiltration modified layer, thereby improving the performance of the membrane. DETAILED DESCRIPTION - Preparation of composite nanofiltration membrane involves (1) dispersing 2-15 g nano graphene powder into 10 mL N-methylpyrrolidone, preparing graphene dispersion after ultrasonic vibration, adding 80 wt.% N-methylpyrrolidone aqueous solution to the graphene dispersion and diluting to 30 mL, adding 0.026 mg methyl N-methylanthranilate, leaving still at 50 degrees C for 3 hours, obtaining nano graphene dispersant, cooling to room temperature, (2) mixing 0.2-3 wt.% nano graphene dispersant aqueous solution and 0.1-4.0 wt.% sodium dodecylbenzene sulfonate aqueous solution in a volume ratio of 1:10, and dispersing hydrophobic PTFE, immersing ethylene microporous membrane for 5 minutes to 12 hours, taking out and drying, obtaining active nano graphene base film, (3) immersing the active nano graphene base film in 0.1-10.0 wt.% amine monomer aqueous solution, leaving still for 5 seconds to 60 minutes, taking out, drying in air, obtaining intermediate film (A), (4) immersing the intermediate film (A) in 0.1-10.0 wt.% solution of an organic solvent of acid chloride monomers, leaving still for 5 seconds to 60 minutes, placing in air to dry, obtaining intermediate film (B), (5) immersing the intermediate film (B) in 0.1-10.0 wt.% aqueous solution of an amine monomer, leaving still for 5 seconds to 60 minutes, taking out and drying to obtain intermediate film (C), (6) immersing the intermediate film (C) in 0.1-10.0 wt.% solution of organic solvent of acid chloride monomer, leaving still for 5 seconds to 60 minutes, placing in air to dry, obtaining intermediate film (D), (7) rinsing the intermediate film (D) with deionized water, and drying in an oven at 30-100 degrees C for 5-40 minutes.