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为改善聚氯乙烯(PVC)膜材料对荷电粒子的截留性能,提出荷正电聚氯乙烯/聚乙烯亚胺(PEI)复合超滤膜制备和研究。利用PVC超滤膜截留特性使PEI在膜表面沉积后热交联的方法制备出PVC/PEI复合超滤膜。研究发现,所制备的膜材料等电点在p H>9.0,表现出典型的荷正电特征。基于孔径筛分和电荷排斥的协同作用,在0.3 MPa测试压力下,该膜对粒径较大的阴离子型染料刚果红和粒径较小的阳离子型染料维多利亚蓝B截留率最高均可达到99%以上。进一步通过利用戊二醛二次交联进一步固定PEI并缩小孔径之后,该膜在对质量浓度1 000 mg/L Ca Cl2的截留率上升至37%,同时通量稳定在30 L/(m2·h)左右。通过调节沉积液浓度及热处理条件,可以对膜的通量和截留进行调控。
In order to improve the retention of charged particles by polyvinyl chloride (PVC) membrane materials, the preparation and study of the composite membranes of positive charge PVC / PEI were proposed. PVC / PEI composite ultrafiltration membrane was prepared by using PVC ultrafiltration membrane retention characteristics to make PEI deposit on the membrane surface and then thermally cross-linked. The study found that the isoelectric point of the prepared membrane material in p H> 9.0, showing typical positive charge characteristics. Based on the synergistic effect of pore size screening and charge repulsion, under the pressure of 0.3 MPa, the highest retention rate of Victoria Blue B with anionic anionic dye Congo red and smaller cationic cationic dye B can reach 99 %the above. After further immobilization of PEI and reduction of pore size by secondary cross-linking with glutaraldehyde, the rejection of CaCl 2 at a concentration of 1 000 mg / L rose to 37% and the flux was stabilized at 30 L / (m 2 · h) around. By adjusting the concentration of the deposition solution and the heat treatment conditions, the membrane flux and entrapment can be regulated.