UV–H₂O₂ degradation of methyl orange catalysed by H₃PW₁₂O₄₀/activated clay

Abstract

A catalyst consisting of phosphotungstic acid (H₃PW₁₂O₄₀) combined with activated clay was prepared by the impregnation method, and an experiment was carried out to evaluate the catalytic activity of the H₃PW₁₂O₄₀/activated clay for the degradation of methyl orange (MO) in the UV–H₂O₂ process. The degradation ratio of MO can be affected by H₂O₂ concentration, reaction time, catalyst dosage, pH and temperature. The reaction temperature should be controlled at less than 70 °C, and the catalyst has a wide applicable pH range in the UV–H₂O₂ process. Hydroxyl radicals were generated in the UV–H₂O₂ system under the action of H₃PW₁₂O₄₀/activated clay, and MO was degraded by hydroxyl radicals. Compared with traditional catalysts used in UV–H₂O₂ systems, H₃PW₁₂O₄₀/activated clay has certain advantages for its practical application.

Keywords:

• heteropoly acid
• phosphotungstic acid
• activated clay
• UV–H₂O₂
• methyl orange

Acknowledgements

The work was supported by Open Foundation from Key Laboratory for New Processing Technology of Nonferrous Metals and Materials of China's Ministry of Education (GXKFJ09-13), Guangxi Science Foundation funded project (2011GXNSFB018017), China Postdoctoral Science Foundation funded project (20110490097), and Guangxi University Scientific Research Foundation funded project (XBZ090701).