The photocatalytic degradation of Reactive Red 195 (RR195) has been investigated in aqueous suspensions by using ultraviolet (UV), sodium hypochlorite (NaOCl) and TiO2/Sep nanoparticles together. To get the TiO2/Sep nanoparticle, the nanocrystalline TiO2 anatase phase on sepiolite was obtained using a sufficient thermal treatment by gradually increasing the temperature from 300, 400 and 500 degrees C for 3 h. Then, TiO2/Sep materials were characterized using different spectral and technical structural analyses with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influence of pH, catalyst amount, oxidant and initial dye concentration was investigated in all the experiments. Maximum colour and chemical oxygen demand (COD) removal were 99.9% and 78% respectively, at a dye concentration of 250 mg L-1. NaOCl dosage of 50.37 mM, 0.1 g L-1 weight of TiO2/Sep and pH of 5.45 in 3 h. In addition, the pseudo-first order model was applied and r(2) values were noted from 0.92 to 0.99. (C) 2009 Elsevier B.V. All rights reserved.