Phenol photonitration upon UV irradiation of nitrite in aqueous solution II:: effects of pH and TiO2

Phenol photonitration and photo nitrosation were studied both in homogeneous and in heterogeneous phase in the presence of TiO2 particles. The effect of pH as well as of the semiconductor particles on the kinetics and products of the reaction was observed. Formation of nitrophenols is enhanced at acidic pH, due to thermal processes initiated by nitrous acid, as well as in the presence of TiO2, due to the photocatalytic oxidation of nitrite. (C) 2001 Elsevier Science Ltd. All rights reserved.