Experimental Study of Influencing Factors and Kinetics in Catalytic Removal of Methylene Blue with TiO2 Nanopowder

In this research, degradation of methylene blue as a dye pollutant was investigated in the presence of TiO2 nanopowders using photolysis and sonolysis systems separately and simultaneously. Effect of different parameters such as catalyst dosage, initial concentration of dye, UV power, pH and type of catalyst on the removal efficiency was ascertained. The results showed that basic pH is proper for the photocatalytic removal of the dye. Furthermore higher UV power and lower initial concentration of dye leads to higher removal percent. Moreover TiO2 showed more photocatalytic activity than ZnO in the nanopowder form. The experimental kinetic data followed the pseudo-first order model in both photocatlytic and sonophotocatalytic processes but the rate constant of sonophotocatalysis is higher than it at photocatalysis process. Finally the reaction order of the rate law respect to nanocatalyst dosage in photocatalysis process is obtained 1.45. High activation energy of this process shows its high sensitivity to temperature.