Photocatalytic Membrane Contactors for Water Treatment

A three-phase catalytic membrane contactor (CMC) was applied in the photocatalytic degradation of organic substances in water. Particles of commercial TiO(2) (P25 and ST01) were deposited on porous ceramic materials. Platinum was deposited onto TiO(2) by the photoreduction method. The activity of the photo-CMC was studied with respect to removing from water model contaminants such as formic acid, oxalic acid, and humic acid. The influence of contacting nitrogen and oxygen with water through the membrane on the efficiency of the removal of those contaminants was investigated. The highest degradation rate was observed under UV (black light) irradiation with simultaneous oxygen supply. A combination of Pt with a photocatalyst improved the lifetime of Pt, as the photocatalysis maintains Pt in the metallic state by its reductive action and prevents Pt poisoning due to the generation of reactive oxygen species. No membrane fouling was observed under the conditions studied. The initial catalytic activity was preserved during several months of the tests and several months of storage in air.