Photodegradation of aqueous methyl orange on MnTiO3 powder at different initial pH

The photodegradation of aqueous methyl orange on MnTiO3 powder was studied in this work. The effects of initial pH and H2O2 on the photodegradation of aqueous methyl orange were studied. Single-phase MnTiO3 powder was synthesized by a sol-gel method. X-ray diffraction analysis shows powders have a particle size of 43.7 nm and rhombohedral pyrophanite structure. The photocatalysis experiments revealed that the efficiency of decolorization of the aqueous methyl orange (1 x 10(-5) M) on the MnTiO3 powder is very fast in sunlight. The rate of decolorization appears larger at initial pH 5 and 9 than at pH 7. H2O2 (2%) can remarkably accelerate the decolorization at low initial pH.