Photocatalytic Membrane Reactors: Case Studies and Perspectives

Photocatalysis by polycrystalline semiconductor oxides is being successfully applied to the abatement of organic and inorganic pollutants both in gas and in liquid phase. In order to increase the efficiency of this method, thecoupling of this technology with the membrane separation process has been the object of sound investigation. In this combination, the membrane may act in different ways: to confine the photocatalytic powder in the reacting suspension, to selectively separate the photoreaction products, or to be the support of photocatalyst. This article reports recent studies in which different types of membranes (such as distillation, dialysis, nanofiltration, pervaporation and osmosis membranes) are used in hybrid systems. An additional advantage of coupling is that the photocatalyst prevents the microbial fouling offering a strong potential for the use of new types of thin-film-composite membrane. Perspectives and future possible application of the synergy between membranes and photocatalytic reactors are also emphasised.