Photocatalytic degradation of an aqueous solution of azo dye (Reactive Red 198) used in textile industries by UV irradiation was investigated. The effect of initial dye concentration, TiO2 loading, pH and H2O2 on degradation rate was ascertained and optimized conditions for maximum degradation were determined. The kinetics of photocatalytic degradation was found to follow a pseudo-first order according to Langmuir-Hinshelwood model. The degradation experiment under optimized reaction conditions was investigated under sunlight. (c) 2006 Elsevier B.V. All rights reserved.