Rapid photocatalytic decolorization of methylene blue using high photon flux UV/TiO2/H2O2 process

UV/TiO2/H2O2 decolorization of methylene blue (MB) was studied under high UV photon flux irradiation; the UV photon flux in this work was ranging from 3.13 x 10(-8) to 3.13 x 10(-6) einstein cm(-2) s(-1). It was shown that photodegradation using UV/TiO2/H2O2 process was much more effective than UV/TiO2 process. Under the optimal conditions of UV/TiO2/H2O2 process, 98% decolorization of 20 mg L-1 MB could be achieved in 10 s. Kinetics of UV/TiO2/H2O2 decolorization follows pseudo-first order with respect to the dye concentration. In UV/TiO2 process, the photocatalytic rate constant increased with the square root of photon flux under high photon flux UV irradiation, and addition of H2O2 could turned the square root relationship closed to linear relationship. The apparent photonic efficiency under various experimental conditions have been calculated and the results also clarified that H2O2 could improve the light utilization efficiency of photocatalytic process. The electrical energy per order (E-EO) values showed that adding H2O2 could reduce energy consumption remarkably. Besides, effect of H2O2 concentration, effect of MB initial concentration and TOC removal were also studied. (C) 2012 Elsevier B.V. All rights reserved.