A photocatalytic reactor using immobilized TiO2 (Degussa P25) on a glass plate was studied on a bench scale using solar light as the source of radiation. The influence of parameters such as the slope of the plate, solar light intensity, flow rate and molar flow rate, as well as the geometry of the reactor, was studied using dichloroacetic acid (DCA) as a model compound. A linear dependence of degradation with solar light intensity, measured at 365 nm, was observed. Experiments with recirculation as well as a single pass of solution suggested no mass transfer limitations in this system. The mineralization of DCA resulted in the production of quantitative amounts of chloride ions. An initial concentration of 5 mmol/L of DCA decayed to 2 mmol/L in about 2 min of irradiation. An exponential decay of degradation was observed with an increase of the molar flow rate, achieving saturation around 1.5 mmol DCA/min. Copyright (C) 1996 Elsevier Science Ltd.565471477