Photocatalytic reduction of hexavalent chromium with illuminated ZnO/TiO2 composite

The purpose of this work was to investigate the photocatalytic reduction of Cr(VI) with illuminated ZnO/TiO2 composite at various catalyst dosage, pH, Cr(VI) concentration, purging gas, type of organic compounds. FT-IR and XRD analysis demonstrated hybridization of ZnO nanoparticles and TiO2 particles. The photocatalytic reduction of Cr(VI) was increased with increasing photocatalyst dosage and decreasing pH. The reaction rate constant (k(obs)) was decreased from 0.0879 to 0.0048 min(-1) with increasing Cr(VI) concentration from 20 to 100 mg/L. Removal efficiency of Cr(VI) by UV/ZnO/TiO2 process was about 99.99%, which was more effective than that by UV/ZnO (82.33%) and UV/TiO2 process (86.07%). (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.