▎ 摘　　要

NOVELTY - Multi-effect coupling method of nanofiltration membrane involves adding 3-10 g/L nano-titanium dioxide to ethanol, homogenizing, adding ethanol solution containing dopamine under nitrogen protection to form mixed solution, heating mixed solution to 40-60 degrees C, stirring, centrifuging, washing precipitate with pure water and ethanol, drying to form surface modified nano-titanium dioxide, mixing graphene oxide aqueous solution and modified nano-titanium dioxide aqueous solution, ultrasonically dispersing, vacuum-filtering dispersion to surface of polysulfone ultrafiltration membrane, stabilizing at room temperature to form graphene oxide-modified nano-titanium dioxide membrane, vacuum-filtering the dopamine-Tris buffer solution to inner layer of graphene oxide-modified nano-titanium dioxide membrane to initiate dopamine copolymerization with graphene oxide and modified nano-titanium dioxide to form composite membrane and immersing composite membrane in polyethylenimine aqueous solution. USE - Multi-effect coupling method of nanofiltration membrane for dye desalination process (claimed). ADVANTAGE - The prepared composite nanofiltration membrane has excellent stability, high permeability to salt ions and high interception rate for small molecule dyes. DETAILED DESCRIPTION - Multi-effect coupling method of nanofiltration membrane involves adding 3-10 g/L nano-titanium dioxide to ethanol, homogenizing, adding ethanol solution containing dopamine under nitrogen protection to form mixed solution where mass ratio of nano titanium dioxide and dopamine is 1:0.1-0.5, heating mixed solution to 40-60 degrees C, stirring for 4-8 hours, centrifuging, washing precipitate with pure water and ethanol, drying to form surface modified nano-titanium dioxide, formulating modified nano-titanium dioxide into 0.1-0.5 mg/L aqueous solution of modified nano-titanium dioxide, ultrasonically processing for more than 30 minutes, formulating graphene oxide into 0.1-0.5 mg/L aqueous solution of graphene oxide and ultrasonically processing for 30-60 minutes, mixing graphene oxide aqueous solution and modified nano-titanium dioxide aqueous solution in volume ratio of 5:3-5:5, preferably 5:3, ultrasonically dispersing, vacuum-filtering the dispersion to surface of the polysulfone ultrafiltration membrane, stabilizing at room temperature for 1-2 hours to form graphene oxide-modified nano-titanium dioxide membrane, vacuum-filtering the dopamine-Tris buffer solution to inner layer of graphene oxide-modified nano-titanium dioxide membrane to initiate in situ dopamine copolymerization with graphene oxide and modified nano-titanium dioxide to form composite membrane, and immersing composite membrane in 0.5-3 %mass polyethylenimine aqueous solution to form positively charged graphene oxide/modified titanium dioxide composite nanofiltration membrane. An INDEPENDENT CLAIM is included for use of the nanofiltration membrane in dye desalination process.