Photocatalytic removal of methyl orange in an aqueous solution by a WO3/TiO2 composite film

WO3/TiO2 composite film was prepared by microarc oxidation technique and characterized by SEM, XRD, UV-vis spectra and Zeta-potential. The photocatalytic activity of WO3/TiO2 composite film was evaluated by examining the degradation of methyl orange. The influence of solution pH and inorganic anions on removal ratio of methyl orange was investigated. Removal ratio of methyl orange decreased with an increase of pH value in acidic solution, while it increased with the pH value in alkaline solution. The influence of added anions on the removal ratio is divided into two aspects. Addition of Cl− and SO 4 2− resulted in a decrease in photocatalytic removal ratio of methyl orange, while it was facilitated by PO 4 3− , HCO 3 − and NO 3 − .