This paper reports experimental results on photocatalytic degradation of sodium dodecyl-benzene sulfonate (DBSNa), using the solar energy concentrator for photocatalysis studies (SECPS). The SECPS operation is based on the concentration of ultraviolet solar radiation on a reactor that contains contaminated water and a catalyst where the photocatalytic effect occurs. This effect produces ruptures in the toxic molecules, until transforming them into harmless compounds. The study focuses on determining how great is the contribution of the catalyst itself and the oxidant agent to the DBSNa photocatalytic degradation. Finally, three conditions were found as optimal for the photocatalytic degradation of DBSNa using the SECPS, which are 0.2 wt% TiO2, 3000 ppm H2O2 and 60 min exposure time. (C) 2000 Elsevier Science B.V. All rights reserved.