Characterization of surface change properties of synthetic microfiltration membranes by means of a streaming current method

Abstract

By use of an improved streaming current method we characterized the pH dependent surface charge properties of six synthetic microfiltration membranes at the constant electrolyte concentration of 10 −4 mol/l. The observed pH dependence of the surface charge properties of the cellulose acetate and the nylon 66 membranes could be explained by the pH influence on the dissociation and protonation of the surface end groups of membrane materials, while the reaction of the surface modification agents, i.e., the wetting agents, with the electrolytes and the ion adsorption on the membrane surfaces, were the main causes for the surface charge of nonionic polymer membranes (polyvinylidenfluoride and polysulfone membranes) in the solutions which had different pH values.