Preparation Of Composite Nanofiber Membrane Material For Oily Wastewater Treatment

Electrospun nanofiber membranes with special wettability have shown great potential application in the field of oil-water separation.However,the preparation of membranes with high separation efficiency,flux and stability still has great challenges.In addition,the separation performances of the membranes to handle with oil-water emulsions and water-soluble contaminants remain to be improved.Therefore,aiming at the above issues,the following two aspects of research are mainly carried out in this paper:1.PAN/GO composite nanofiber membranes were prepared by soaking and electrostatic spinning respectively.The surface morphology,chemical composition and wettability of the composite films were characterized by FE-SEM,ATR-FTIR,XRD and contact angle measurement.The separation performances of the membranes under different preparation methods and pretreatment were studied,and the best sample was screened out by the separation efficiency,separation flux and stability.Finally,the separation performances of amino(-NH₂)and hydroxyl(-OH)modified composite nanofiber membranes for immiscible oil-water mixture and oil-in-water emulsion were studied.The experimental results show that the composite nanofiber membrane prepared by electrospinning had a more uniform surface morphology and a similar hierarchical structure inside and outside of the membrane.The separation efficiencies of EPGO-1.5 for different oil-water mixtures were higher than96.2%,and the separation flux for hexane/water mixture could reach 1500.3±4.7 L/h·m².The results of the stability experiment show that the membrane prepared by electrospinning had a recycling performance,and its anti-tearing performance was obviously better than that of the membrane prepared by soaking method.2.Double layer Janus nanofiber membranes(PAN/PVA-CS)were prepared by electrospinning.The surface microstructure and wettability of the composite membranes were controlled by changing the amount of chitosan(CS).The effects of CS on the surface chemical composition,morphology and wettability of the composite membranes were studied,and the bilayer fiber membrane with underwater superoleophobicity on one side and underoil superhydrophobicity on the other side was obtained.The separation efficiency,chemical stability,separation performances of the membranes for O/W and W/O emulsions and immiscible oil-water mixtures were investigated.Finally,the adsorption capacities of Congo red(CR)on fiber membranes with different CS contents were studied,and the adsorption kinetics and adsorption isotherm model were investigated.The results show that the Janus membranes had high separation efficiencies for both light oils and heavy oil.To be specifically,the separation efficiencies of all the light oil/water mixtures were higher than97%,and the separation efficiency of heavy oil/water mixture was 95%.The CR adsorption process accords with the pseudo-second-order kinetics and Freundlich adsorption isotherm model.