为探索分离染料/盐混合物体系的新型膜材料和技术，提出荷正电、交联型聚氯乙烯(PVC)/聚乙烯亚胺(PEI)超滤膜研究。通过在低温下共混制备制膜液抑制交联、热处理铺展液膜促进交联、非溶剂诱导相转化固化成多孔膜三个步骤制备出PVC/PEI超滤膜。研究了膜的交联、荷电性、力学性能、微观结构以及对染料/盐的分离性能。研究发现，所制备的膜韧性大幅度提高，等电点在pH>9.0，截留孔径在30 nm左右，表现出典型的荷正电超滤膜特征。在0.15 MPa压力测试条件，膜对水溶液中NaCl、CaCl2、Na2SO4等无机盐的截留率在5%以下，对多分散型阳离子染料维多利亚蓝B、阴离子染料酸性铬蓝K的截留率分别为96%和55%，通量达到110 L×(m2×h)-1，充分发挥了孔径筛分及静电排斥两种分离机制，在阳离子染料/盐混合物分中具有高通量、高效率特性。%A novel positively-charged polyvinyl chloride (PVC)/ poly(ethylene imine) (PEI) ultrafiltration (UF) membrane with crosslinking structure was proposed to explore membrane material and technology for dye/salt separation. A modified non-solvent induced phase separation route was created for the preparation of these PVC/PEI UF membranes, which consisted three simple steps including (1) dissolving PVC and PEI in DMAC at lower temperature to prepare a homogeneous casting solution;(2) spreading the casting solution into liquid film via a heating process to form crosslinking structure of PVC/PEI;and (3) immersing the liquid film in water to generate solid PVC/PEI membranes. The prepared PVC/PEI membranes were characterized in terms of composition, surface potential, mechanical property, pore size, structure and dye/salt separation. The results reveal that the crosslinking degree is higher than 60%, and the isoelectric points are over pH 9. For the typical PVC/PEI UF membrane with pore size of 30 nm, the permeation flux of NaCl, CaCl2 and Na2SO4 aqueous solutions are higher than 110 L×m-2×h-1 at 0.15 MPa. The rejection of all these salts is lower than 5%, while the rejection of positive Victoria blue B and negative acid chrome blue K are 96%and 55%, respectively. It is the positive-positive repulsion effect between PVC/PEI membrane and Victoria blue B that generates the corresponding high rejection. The prepared PVC/PEI membranes show great potential in dye/salt mixture separation from aqueous solutions.
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