离子效应对纳滤膜表面Zeta电位测定的影响

Influence of ionic effect on Zeta potential measurement of nanofiltration membrane

采用流动电位法,用固体表面电位测定仪考察电解质溶液种类、浓度、p H对纳滤膜表面Zeta电位的影响。结果表明,二价离子溶液比一价离子溶液对纳滤膜表面Zeta电位作用明显,同价态离子的离子半径越小,Zeta电位越大;随着离子强度的增加,Zeta电位越小,在低离子浓度下Zeta电位值稳定性,重复性好;随着溶液p H的变化(3~10),纳滤膜的表面呈现两性性质,等电位点在p H 4.5~5.0之间。在测试纳滤膜表面Zeta电位时,推荐选择0.001mol/L的KCl电解质溶液。

The flow potential method was used to determine the effect of electrolyte solution type, concentration and pH on Zeta potential of the nanofiltration membrane using a solid surface potential analyzer. The results showed that the effect of the divalent ion solution on the surface Zeta potential of the nanofiltration membrane was more obvious than that of the monovalent ion solution. In the case of the same valence ion, the smaller as the ion radius was, the larger the zeta potential was. As the ion intensity increased, Zeta potential was more smaller, the Zeta potential was more stable at low ion concentration and showed the better repeatability, with the change of pH （3-10）, the surface of the nanofiltration membrane exhibited amphoteric nature, and the isoelectric point was between 4.5 and 5.0. When measuring the zeta potential of the nanofiltration membrane surface, 0.001 mol/L KCl electrolyte solution was generally selected.