Photocatalytic treatment of phenol and 2,4-dichlorophenol in a solar plantin the way to scaling-up

The photocatalytic treatment of phenol and 2,4-dichlorophenol (2,4-DCP) has been tested by using titania in suspension as catalyst. Experiments were d one at the solar facilities of the Plataforma Solar de Almeria (Spain). Two experimental devices were used: CPCs modules; and flat reactor. Reaction k inetics is order one with respect to the pollutant (phenol or 2,4-DCP) conc entration. Two different kinetic constants were fitted from experimental da ta by considering only time influence on the reaction rate or by considerin g the radiation influence and assuming that reaction rate is proportional t o the square root of photonic flow. In all cases, kinetic constant increase s when catalyst concentration does it, reaches a maximum (at 0.5 g/l of cat alyst in the CPCs case, and at 0.2 g/l in the flat case), and after this ma ximum, decreases. When kinetic constants obtained in the two utilities test ed are compared, important differences were found when only dependence on t ime is considered. However, results improve when radiation influence is con sidered, and the values obtained in both devices are more close. This fact indicates the influence of reactor geometry and radiation on the reaction r ate, and their importance in the scaling-up. Finally, the efficiencies of C PCs and flat reactor are compared attending to the collector area needed to obtain the same conversion in the pollutant treatment. It seems that CPCs work better, however several factors can influence (for instance, weather: cloudy or sunny days) and more accurate studies are needed. (C) 1999 Elsevi er Science B.V. All rights reserved.