▎ 摘　　要

NOVELTY - Preparing multi-layer polyamide membrane composite reverse osmosis membrane comprises (i) dissolving polysulfone resin in N,N-dimethylformamide, adding 4-5% additive, stirring to prepare uniformly dispersed solution, filtering and vacuum degassing, uniformly coating solution on the non-woven fabric, immediately immersing in pure water and solidifying into film, and spraying on the polysulfone film for sulfuric acid solution to obtain polysulfone-based membrane, (ii) adding tris(hydroxymethylaminomethane) into a beaker, add proper amount of ultrapure water to dissolve, transferring to a 1 l volumetric flask, making up to volume, and using hydrochloric acid to obtain tris-hydrochloric acid buffer, adding dopamine into the above-mentioned buffer solution to form a dopamine-modified solution, and filtering the dopamine-modified solution on polysulfone-based membrane to form polydopamine layer on the membrane surface and in the membrane pores. USE - The method is useful for preparing multi-layer polyamide membrane composite reverse osmosis membrane. ADVANTAGE - The method provides a stable reverse osmosis membrane with high rejection rate and high permeability and strong anti-bacterial. DETAILED DESCRIPTION - Preparing multi-layer polyamide membrane composite reverse osmosis membrane comprises (i) dissolving 17-19% polysulfone resin in N,N-dimethylformamide, adding 4-5% additive, stirring at 50-100degrees Celsius for 3-6 hours to prepare uniformly dispersed solution, filtering and vacuum degassing, uniformly coating solution on the non-woven fabric with a wet film thickness of about 100-200 microm, immediately immersing in pure water at 20-30degrees Celsius to gel and solidifying into film, and spraying on the polysulfone film for 30-60% sulfuric acid solution at 50degrees Celsius to obtain polysulfone-based membrane, (ii) adding 6-8.5 g tris(hydroxymethylaminomethane) into a beaker, add proper amount of ultrapure water to dissolve, transferring to a 1 l volumetric flask, making up to volume, and using hydrochloric acid to adjust pH to 6 -8 to obtain tris-hydrochloric acid buffer, adding 0.2-0.4 g dopamine into the above-mentioned buffer solution to form a dopamine-modified solution, and filtering the dopamine-modified solution on polysulfone-based membrane under pressure to form polydopamine layer on the membrane surface and in the membrane pores, (iii) dissolving 0.06-0.1 wt.% aromatic polyfunctional amine and 0.5 wt.%surfactant in water successively, and uniformly stirring, adding sodium hydroxide into the obtained aqueous solution to adjust the pH value of the solution to 6-10 to obtain the aqueous phase liquid, dissolving 0.01-0.03 wt.%aromatic polyfunctional acyl halide in naphtha, uniformly stirring to obtain oil phase solution, immersing base film formed with the polydopamine layer in the aqueous phase solution for 30-60 seconds, removing the excess aqueous phase liquid on the surface of the non-woven base film with a surface-polished stainless steel roller, immersing the base film in the oil phase solution for 40-60 seconds, removing the residual oil phase liquid on the surface, entering the oven at 60-90degrees Celsius for 4-8 minutes, and washing to obtain the bottom polyamide, (iv) dispersing 0.1-0.5 g graphene oxide in 100 ml water by ultrasonic to make graphene oxide/water dispersion, dissolving 0.1-0.5g 3-aminopropylphosphonic acid in 40 ml ethanol to prepare 3-aminopropylphosphonic acid/ethanol solution, adding 3-aminopropylphosphonic acid/ethanol solution into graphene oxide/water dispersion, stirring and refluxing for 10-15 hours at 80-95degrees Celsius, suction filtering, washing the filter residue in ethanol to obtain phosphonic acid-modified graphene oxide, dissolving 0.3-0.5 wt.% aromatic polyfunctional amine and the surfactant in water successively, uniformly stirring, adding sodium hydroxide into the obtained aqueous solution to adjust the pH value of the solution to 6-10 to obtain an aqueous phase liquid, adding phosphonic acid-modified graphene oxide and uniformly stirring, dissolving 0.1-0.3 wt.%aromatic polyfunctional acyl halide in the naphtha, stirring uniformly to obtain an oil phase liquid, immersing base film formed with the bottom polyamide layer in the aqueous phase solution for 30-60 seconds, and removing excess aqueous phase liquid on the surface of the non-woven base film with a surface-polished stainless steel roller, and immersing base film in the oil phase liquid for 40-80 seconds, removing the residual oil phase liquid on the surface, entering into a 60-90degrees Celsius oven for 5 minutes, and washing to obtain film with a top polyamide layer, (v) preparing chitosan complexed silver antibacterial agent by taking soluble silver salt and chitosan with a weight ratio of 1:10-70, adding water into the reaction kettle, turning on the mixer, controlling the pH value of the reaction to be 3.6-8.5, reacting at -16 to 70degrees Celsius, slowly adding chitosan, stirring until chitosan is completely dissolved to form a solution with a mass concentration of 0.3-0.9, adding soluble silver salt, stirring for 0.2-20 hours and adding glutaraldehyde, preparing protective layer modification solution with a concentration of glutaraldehyde of 0.2-0.8 wt.%, immersing film containing the top polyamide layer in the protective layer modification solution for 0.2-4 hours to carry out a cross-linking reaction.