芳香聚酰胺纳滤膜在电解质溶液中的动电现象

Electrokinetic phenomena of aromatic polyamide nanofiltration membrane in electrolyte solutions

研究芳香聚酰胺纳滤膜在不同电解质溶液中的流动电位,考察膜两侧压差、电解质浓度、离子价态及溶液pH值对流动电位的影响,用Helmoltz-Schmolukovski方程与Gouy-Chapmann方程计算膜表面的Zeta电位与电荷密度。结果表明:芳香聚酰胺膜表面荷负电荷;流动电位和Zeta电位绝对值均随电解质浓度的增大而减小;溶液pH值对流动电位和Zeta电位的影响较大;当电解质溶液浓度相同时,芳香聚酰胺膜的流动电位和Zeta电位的绝对值在二价阳离子电解质溶液中比一价阳离子的电解质溶液中均要小,但前者中的等电位点的pH值略大。

The streaming potential of aromatic polyamide（APA） nanofiltration membrane was investigated in different kinds of electrolyte solutions, the effects of trans-membrane pressure, electrolyte concentration, ion valence and pH value of solution on the streaming potential of the membrane were investigated. The Zeta potential and the surface charge density of the membrane were calculated according to Helmoltz-Schmolukovski and Gouy-Chapmann equations. The results show that the aromatic polyamide membrane is negatively charged, the absolute values of the streaming and Zeta potentials decrease with increasing solute concentration under the same pressure, the pH value of electrolyte solution has great effects on the streaming and Zeta potentials of the membrane surface. Both the absolute values of the streaming potential and Zeta potential of APA membrane in the electrolyte solution with bivalence cation are smaller than those with monovalence cation, but the pH value of IEP of the former is a little greater than that of the later.