Electrokinetic phenomena of a polyethylene microfiltration membrane in single salt solutions of NaCl,KCl,MgCl_2,Na_2SO_4,and MgSO_4

摘要

The streaming potential measurements of a polyethylene microfiltration(PE-MF)membrane were carried out under aqueous solutions of five single salts(NaCl,KCl,MgCl_2,Na_2SO_4,and MgSO_4);the zeta potential and surface charge density of the membrane were estimated on the basis of the Helmholtz-Smoluchowski equation and the Gouy-Chapmann theory.The results show that the PE-MF membrane has a weak negative charge due to the specific sorption of ions,and behaves almost as a certain zeta potential in a very dilute salt solution and as almost a certain surface charge density in a solution with a concentration more than 4 mol center dot m~(-3).However,the streaming potential,the zeta potential and the surface charge density of the membrane depend strongly on the salt concentration and the type and valence of ions.