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

The photocatalytic degradation of methylene blue (MB) in aqueous solution was studied using UV source in presence of synthesized $BaTiO_3$ as photocatalyst and in combination with different concentrations of $H_2O_2$. The experiments were carried at different catalyst loading (0.05 & 0.1 wt %), pH (3, 7 & 9) and $H_2O_2$ 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 $H_2O_2$. There was no appreciable degadation seen in presence of catalyst alone. Discoloration of the dye was very nearly complete using $UV/H_2O_2$. Neither UV radiation nor $H_2O_2$ 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 $BaTiO_3/UV$ system. The optimum dosage of $H_2O_2$ for 12 ppm concentration of the dye was found to be 2 mL/L for $UV/H_2O_2$. 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 $BaTiO_3/UV/H_2O_2$ system. An enhancement in the degradation rate was observed with this system compared to $UV/H_2O_2$ system.