聚砜中空纤维超滤膜的流动电位研究

通过对聚砜中空纤维超滤膜在不同电解质溶液中的膜表面流动电位的研究,考察了膜两侧压差、电解质浓度及离子价态及溶液pH对流动电位的影响,用Helmoltz-Schmoolukovski方程与Gouy-Chapmann方程计算了膜面电荷密度,测定了污染膜经不同清洗剂清洗后的流动电位和水通量.结果表明,流动电位绝对值随电解质浓度的增大而减小;同样电解质浓度下,阳离子价态越高,流动电位绝对值越小.溶液pH对流动电位影响较大,当溶液pH超过等电点时,流动电位绝对值随溶液pH的增加而增加.在一定电解质浓度范围内过滤电解质溶液时,流动电位和通量的衰减幅度不同,对含高价阳离子的电解质溶液,流动电位的衰减比通量衰减更明显.

Research on streaming potential of polysulfone hollow fiber ultrafiltration membrane

The streaming potential of polysulfone hollow - fiber ultrafiltration membrane was investigated for the treatment of different kinds of electrolyte solutions, the effects of trans - membrane pressure, electrolyte concentration, ion valence and pH on the streaming potential of the membrane were investigated. The surface charge densities of the membranes were calculated according to Helmoltz - Schmolukovski equation and Gouy -Chapmann equation. The streaming potential and flux of both the fouled membrane and the cleaned membrane were also measured. The results show that the streaming potential decreases with the increase of the solute concentration under the same pressure, the higher valence the cation, the smaller the absolute value of streaming potential under the same electrolyte concentration. The pH value of electrolyte solution has great effects on the streaming potential of the membrane surface, when the pH of the electrolyte solution is greater than that of the isoelectric point (IEP), the absolute value of streaming potential and flux increase with pH value. In addition,the declination of the streaming potential is different from that of the permeate flux, the former is more obvious than the latter for the treatment of electrolyte solution with high valence of cation.