▎ 摘　　要

NOVELTY - Synthesis of graphene oxide/black talc composite nanofiltration membrane involves (A) preparing black talc nanosheet dispersion liquid, (B) preparing graphene oxide dispersion liquid, (C) preparing dopamine solution (D) obtaining poly-dopamine coated macromolecule porous support layer bottom film, mixing the black talc nanosheet dispersion liquid obtained in step (A) and the graphene oxide dispersion liquid obtained in step (B) to obtain dispersed mixed solution, (E) vacuum filtering the dispersed mixed solution on the poly-dopamine coated macromolecule porous support layer bottom film to obtain macromolecule porous support layer supporting bottom film loaded with graphene oxide/black talc and (F) dripping piperazine and organic phase solution of trimesoyl chloride. USE - Synthesizing graphene oxide/black talc composite nanofiltration membrane for desalination treatment. ADVANTAGE - The synthesis of composite nanofiltration membrane is simple, easy to operate, and obtains a stable product. The poly-dopamine coated bottom membrane can improve the hydrophilicity of the membrane surface, prevent particle agglomeration, and increase the water flux of the membrane. The composite nanofiltration membrane can improve the membrane flux in desalination treatment under a driving pressure of 0.3 MPa, maintaining the rejection rate, has lower energy consumption, and reduces cost. DETAILED DESCRIPTION - Synthesis of graphene oxide/black talc composite nanofiltration membrane involves (1), transferring processed 1-2 mu m fine black talc powder into stainless steel high pressure kettle of PTFE liner, placing under 50-200 degrees C for 1-12 hours, cooling to room temperature, collecting the solid product and dispersing in deionized water, processing at 50-300 W for 12-24 hours, centrifuging, water washing and drying to obtain the black talc nanosheet, adding deionized water and ultrasonically dispersing to obtain 0.01-1 g/L black talc nanosheet dispersion liquid, (2), adding graphene oxide into deionized water and ultrasonically dispersing to obtain 0.1-1 g/L graphene oxide dispersion liquid, (3) preparing pH 10.0 solution of Tris(hydroxymethyl)aminomethane-hydrochloric acid buffer, adding dopamine, ultrasonically dissolving to obtain 0.5-3 g/L dopamine solution, soaking the bottom film of a macromolecule porous support layer which comprises one or more of polysulfone, polyvinylidene fluoride, polyimide, polyetherimide or polypropylene, into the dopamine solution, stirring at 80-150 rpm and reacting for 12-48 hours and washing using deionized water to obtain the poly-dopamine coated macromolecule porous support layer bottom film, (4), stirring the black talc nanosheet dispersion liquid prepared in step (1) and the graphene oxide dispersion liquid in the step (2) in the mass ratio of 1-5:1 for 1-10 hours and ultrasonically dispersing to obtain dispersed mixed solution, (5), vacuum filtering the dispersed mixed solution obtained in step (4) on the poly-dopamine coated macromolecule porous support layer bottom film prepared in step (3) and drying the obtained composite film in the air for 10-30 minutes to obtain the macromolecule porous support layer bottom film loaded with graphene oxide/black talc, and (6), uniformly dripping 0.6-4 wt.%, 0.2-1 mL/cm2 piperazone aqueous solution into the macromolecule porous support layer bottom film loaded with graphene oxide/black talc obtained in step (5) for 2-5 minutes, removing the remaining piperazine aqueous solution until the surface is anhydrous, dripping 0.5-2 wt.%, 0.1-1 mL/cm2 organic phase solution of trimesoyl chloride, resting for 1-3 minutes, removing the remaining organic phase solution, drying at room temperature and obtaining graphene oxide/black talc composite nanofiltration membrane. The organic phase in the organic phase solution of trimesoyl chloride comprises one or more of n-hexane, toluene, p-toluene, cyclohexane or petroleum ether. The volume of the dispersion mixture is 5-200 mu L/cm2 in terms of the area of the bottom membrane of the macromolecule porous support layer coated with polydopamine.