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 (ζ) of decolorization, as well as mineralization under various experimental conditions have been calculated.