Streaming potential and ion transmission during ultra- and microfiltration on inorganic membranes

The streaming potential, permeate flux and ion transmission are measured on inorganic ultra-and microfiltration membranes. The streaming potential depends on charge distribution, which is modified by changing the pH, the ionic strength, and the nature of ions. The study reveals that it is indispensable for characterizing the membrane state from a charge point of view. Moreover, the ion transmission and pH variations between retentate and permeate are correlated to the membrane net charge, quantified by streaming potential values. The influence of membrane pore radius on streaming potential measurements and on apparent zeta potential values are analyzed in relation with the double layer overlapping. This study points out the effect of membrane net charge on ion transmission even in the case of a very large pore radius as for microfiltration membranes.