HETEROGENEOUS PHOTOCATALYTIC OXIDATION OF NITRITE OVER IRON-DOPED TIO2 SAMPLES

The photocatalytic oxidation of nitrite to nitrate over iron-doped TiO 2 in aqueous medium under different experimental conditions has been i nvestigated. Specimens of TiO2 doped with different amounts of Fe3+ (b etween 0.2 and 10 wt.-%) were used; the most photoactive sample was fo und to be TiO2 doped With 0.5 wt.-% of iron. The nitrite photooxidatio n follows zero-order kinetics for all iron-doped TiO2 samples tested, while for pure TiO2 Langmuir-Hinshelwood kinetics is obtained. The rol e played by Fe3+ in the photocatalytic processes at the semiconductor- electrolyte interface is discussed.