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.