Photocatalysed degradation of uracil in aqueous titanium dioxide suspensions: mechanisms, pH and cadmium chloride effects

Upon UV irradiation, in O-2 saturated aqueous titanium dioxide suspensions, uracil is almost completely mineralised. Most of the organic compounds occ urring during the photodegradation process have been identified by means of liquid chromatography and mass spectrometry coupled techniques (LC-MS). Th e first step of the mineralisation leads to the formation of uracilglycol. Then, the main products generated during the photodegradation exhibit new f unctions such as polyol, carboxylic and aldehyde. The presence of urea has been clearly evidenced. At the end of the process, the ultimate step is the formation of nitrate and ammonium ions. The formation kinetics of intermed iate products are modified by pH variation and CdCl2 addition. (C) 2000 Els evier Science S.A. All rights reserved.