Photocatalytic degradation of industrial residual waters

Solar photocatalytic water mineralization using the interaction between ultraviolet radiation and titanium dioxide (TiO2) has a strong potential for the destruction of toxic organics in water, as widely demonstrated in recent years. Testing of several real waste-water samples at the Plataforma Solar de Almeria (PSA) has proven the feasibility of solar photocatalytic detoxification for the treatment of industrial effluents with organic loads of hundreds of mg/dm(3). The use of peroxydisulfate (S2O8-2) as an additional oxidant (electron scavenger) has an outstanding effect, producing an important increase in the degradation rate. This oxidant has also been more efficient than hydrogen peroxide (H2O2) in the treatment of waste water. A comparison between two different surface-area TiO2 powders showed no significant differences. Two types of solar collectors, a two-axis parabolic trough system and a compound parabolic concentrating (CPC) system, have been compared, the latter having the best performance for the selected experimental site (latitude + 37 degrees, semi-arid climate). Copyright (C) 1996 Elsevier Science Ltd.