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 3.13×10^-8 to 3.13×10^-6einsteincm^-2s^-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 20mgL^-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.