Photocatalytic activity of sulfate modified titania 3: Decolorization of methylene blue in aqueous solution

The photocatalytic decolorization of methylene blue (MB) was studied under solar radiation over sulfate modified titania. The results obtained were compared with that of adsorption and under UV light. It was found that percentage of decolorization was the highest under solar radiation. The effects of pH, time, adsorbate concentration, catalyst dose, H2O2, potassium persulfate and sodium chloride were studied on the percentage of decolorization. The degradation rate followed first-order kinetics. The percentage of decolorization increased with increase in pH of the suspension. The presence of Cl− ion decreased the rate of decolorization where that of potassium persulfate increased the rate. Addition of H2O2 facilitated the generation of OH radicals, which in turn increased the rate of decolorization. The catalyst could be regenerated for repeated use.

The photocatalytic decolorization of methylene blue was highest under solar radiation compared to adsorption and UV light over sulfate modified titania. The effects of pH, time, adsorbate concentration, catalyst dose, H2O2, potassium persulfate and sodium chloride were studied on the percentage of decolorization. While optimising the photocatalytic decolorization conditions it was found that 100 ppm of methylene blue can be completely decolorized using 1.6 g L−1 of sulfated titania in 4 h under solar radiation. Figure optionsDownload as PowerPoint slide