Photodegradation of the textile dye Reactive Black 5 in the presence of semiconducting oxides

The photocatalytic degradation of Reactive Black 5, a textile azo dye, has been investigated in aqueous heterogeneous solutions containing semiconductor oxides as photocatalysts. The disappearance of the organic molecule follows approximately a pseudo‐first kinetic order according to the Langmuir–Hinshelwood model. CO ₂, NO₃⁻, and SO₄ ²⁻ ions have been identified as mineralization products. Various commercial photocatalysts were compared with respect to their decolorization efficiency, as well as the production of CO₂. The effect of pH and H₂O₂ on the reaction rate was ascertained. © 1999 Society of Chemical Industry