The photocatalytic decolorization of methylene blue (MB) was studied under solar radiation over sulfate modified fitania. 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)-O-center dot radicals, which in turn increased the rate of decolorization. The catalyst could be regenerated for repeated use. (c) 2006 Elsevier B.V. All rights reserved.