Photooxidation of eosin Y in the presence of semiconducting oxides

The photocatalytic degradation of eosin Y, an anionic xanthene fluorescent dye, has been investigated in aqueous heterogeneous solutions containing TiO2 P-25 and ZnO as photocatalysts. The disappearance of the organic molecule follows approximately a pseudo-first kinetic order according to the Langmuir-Hinshelwood model. The effect of H2O2 on the reaction rate is ascertained. CO2 and Br- ions have been identified as mineralization products, while toxicity experiments showed a 85% reduction of the toxicity of an eosin Y solution after 60 min of photocatalytic treatment. The initial photonic efficiency of decolorization, as well as mineralization under various experimental conditions have been calculated. (C) 2002 Elsevier Science B.V. All rights reserved.