Zeta Potential of Alumina Membrane

Since, the zeta potential of membranes affect the filtration characteristics of the solid-liquid separation process for membrane bioreactors, the variability of zeta potential with operating conditions was investigated for alumina membranes, used for membrane bioreactor system. The surface hydroxyl group density of alumina mambranes was also investigated. The distilled water immersion test revealed that the isoelectric point of the membrane shifts from 5.5, initial value, to 6.0 in distilled water at 37°C after 1000h, and also, to 6.5 after distilled water reflux for 100h. The measurement of surface hydroxyl group density showed that refluxing for 100h is equivalent to immersion in water at 37°C for several years. This suggests that the variability in zeta potential under normal mambrane operating conditions, for 2-3 years, is negligible. It is also apparent that the variability in pore size distribution has negligible effects.