| Oil pollution caused by oil spills,domestic sewage or industrial wastewater discharges has become a serious threat to the water environment and human health.Oil-water separation is an important means to deal with this problem effectively.Membrane separation is a highly efficient and low energy consumption method that can ultimately achieve water purification.However,as the main component in the membrane separation process,the existing oil-water separation membranes still face problems such as low separation flux,low separation efficiency,and poor fouling resistance to contaminants in water such as oil and biological macromolecules.Hydrophilic modified separation membranes can enhance water permeability without reducing the separation efficiency and improve the fouling resistance of membrane.The hydrophilicity of the electrostaticspun fiber membranes was modified by means co-blending,polymer cross-linking,and Janus membrane construction.Furthermore,their separation performance for oil-water mixtures and emulsions was studied further.The main contents were as follows.(1)A hydrophilic PVP-PAN fiber membrane was prepared by a simple blending strategy and electrostatic spinning technology,and the effects of molecular weight and incorporation of hydrophilic polymer PVP on the surface morphology,wettability and oil-water separation properties of the fiber membrane were systematically investigated.The results showed that the incorporation of PVP did not affect the fiber morphology and intermolecular forces existed between PVP and PAN;the hydrophilic and oil-water separation performance of the separation membranes containing low molecular weight PVP was optimal;the separation performance of the membranes was optimal when the mass ratio of PVP to PAN was 1:20.The PVP-PAN fiber membrane prepared under optimal conditions can effectively separate oil-water mixture and oil-in-water emulsion,and the separation flux of oil-water mixture can reach up to 83080Lm-2h-1bar-1,and the separation flux of emulsion can reach 796Lm-2h-1,and the separation efficiency of different oils is more than 98%.The membrane has good chemical stability,certain cyclic stability and good oil fouling resistance.(2)The c PVP-PAN composite membrane was prepared by chemical cross-linking which hydrophilic polymer PVP was crosslinked on the fiber surface for fixing hydrophilic.The surface morphology,chemical composition,surface wettability and oil-water separation performance of the composite membrane were studied by various means such as SEM,FTIR,XPS,contact angle test and oil-water separation performance test.The results show that the composite membrane has good oil-water separation performance,which can effectively separate oil water mixture and oil in water emulsion,and the composite membrane has excellent anti-protein adsorption performance and anti-oil fouling performance.The separation flux of the composite membrane was 20610Lm-2h-1bar-1 for oil-water mixtures and 569Lm-2h-1 for emulsions under gravity conditions..(3)Janus composite membranes with three-layer structure were prepared by sequential electrostatic spinning with PAN as the main material,PVDF as the hydrophobic modified material and SBMA as the hydrophilic modified material.The wettability,oil/water contamination resistance and oil-water separation performance of the composite membranes were systematically investigated.The results showed that the PFPS Janus composite membrane could separate oil-water mixture and water-in-oil emulsion under gravity-only conditions,and the separation fluxes of oil-water mixture were 5741Lm-2h-1 for oil and1678Lm-2h-1 for water,and the separation efficiencies of different oils were higher than98%,and the separation fluxes of emulsions were 1184Lm-2h-1.In addition,based on the hydrophilic and hydrophobic interaction,the membrane has the performance of unidirectional water transport,the characteristics of sweat-absorbing and moisture-wicking fabric,and the operation of underwater oil collection or water collection under oil can be realized. |
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