Photodegradation of methylene blue dye using UV/BaTiO₃, UV/H₂O₂ and UV/H₂O₂/BaTiO₃ oxidation processes

Abstract

The photocatalytic degradation of methylene blue (MB) in aqueous solution was studied using UV source in presence of synthesized BaTiO₃ as photocatalyst and in combination with different concentrations of H₂O₂. The experiments were carried at different catalyst loading (0.05 & 0.1 wt %), pH (3, 7 & 9) and H₂O₂ dosage (0.5 – 6 mL/L). The degradation rate was found to be strongly dependent upon various experimental parameters such as catalyst loading, pH, and dosage of H₂O₂. There was no appreciable degradation seen in presence of catalyst alone. Discoloration of the dye was very nearly complete using UV/H₂O₂. Neither UV radiation nor H₂O₂ alone was able to decolourize the dye. The best degradation results were observed under optimum conditions of catalyst loading of 0.05 wt%, pH 9 for BaTiO₃/UV system. The optimum dosage of H₂O₂ for 12 ppm concentration of the dye was found to be 2 mL/L for UV/H₂O₂. The experimental kinetic data on the degradation of the dye followed the pseudo first order rate. Tests were further carried out for degradation of the dye using BaTiO₃/UV/H₂O₂ system. An enhancement in the degradation rate was observed with this system compared to UV/H₂O₂ system.