Synthesis by sol-gel of WO3/TiO2 for solar photocatalytic degradation of malathion pesticide

In this study, TiO2 modified with WO3 (2 wt.%) was prepared by the sol-gel method, and its photocatalytic activity (PCA) under solar irradiation was evaluated using malathion as the model contaminant. The catalyst was synthesized using tetra butyl orthotitanate (TBT) and ammonium p-tungstate (ApT) as precursors. For comparison, bare TiO2 was also prepared by the sol-gel process. The resulting photocatalysts were characterized by XRD, BET, DRUV-vis, FE-SEM, TEM and STEM. The synthesized TiO2 materials exhibited a crystalline anatase phase with an average particle size of 20 nm. Results of malathion degradation using solar light, indicated that 2% WO3/TiO2 showed better catalytic performance than sol-gel TiO2, achieving a complete degradation after 2 h, while TOC abatement was 63% after 5 h. These results suggest that 2% WO3/TiO2 catalyst is a promising material for solar photocatalytic treatment of water contaminated by pesticides. (C) 2012 Elsevier B.V. All rights reserved.