Separation of titanium dioxide from photocatalytically treated water by cross-flow microfiltration.

This study focuses on the separation of titanium dioxide from water by cross-flow microfiltration (CMF) within wastewater treatment by photocatalysis using slurry reactor systems. The systematic studies have shown that the separation performance of TiO2 particles is strongly affected by cross-flow velocity, transmembrane pressure, feed concentration, pH of the suspension and ionic strength. An extreme sensitivity to pH and electrolyte concentration indicates the importance of interfacial effects in solid-liquid separation of TiO2 particles. Under optimal conditions, permeate fluxes of up to 1250 l m-2 h-1, approaching those of pure water, could be obtained with a polypropylene membrane which is not sensitive to abrasion. The obtained results makes TiO2 separation by cross-flow microfiltration attractive in solar-catalytic detoxification.