Immobilized titania (TiO2) batch reactors reduced hexavalent chromium (Cr(VI)) in the form of potassium dichromate (K2Cr2O7) to trivalent chromium (Cr(III)) in aqueous solution at pH 3 under 171 W/m(2) light intensity. The light source was a 125-W ultraviolet (UV) lamp. The Cr(VI) reduction showed zero-order kinetics (k(0)), while the Cr(VI) adsorption fitted with first-order kinetics (k(1st)). Adsorption capacity increased with increasing initial Cr(VI) concentration, and the area of immobilized TiO2 limited the reduction efficiency. The lifetime of fresh immobilized TiO2 was approximately 14 h. In addition, the regeneration of TiO2 with 3 M sodium hydroxide (NaOH) was necessary to improve adsorption reaction. (c) 2005 Elsevier B.V All rights reserved.