This study evaluated the performance of photo-Fenton reaction initiated by the UV irradiation with H2O2/Fe3+, denoted as UV/H2O2/Fe3+, to decompose di-n-butyl phthalate (DBP) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the decomposition of DBP by the UV/H2O2/Fe3+ process. A second-order kinetic model with respect to TOC was adequately adopted to represent the mineralization of DBP by the UV/H2O2/Fe3+ process. The experimental results of this study suggested that the dosages with 4.74 x 10(-5) mol min(-1) L-1 H2O2 and initial Fe3+ loading concentration of 4.50 x 10(-4) mol L-1 in the solution at pH 3.0 with 120 mu W cm(-2) UV (312 nm) provided the optimal operation conditions for the mineralization of DBP (5 mg L-1) yielding a 92.4% mineralization efficiency at 90 min reaction time. (c) 2005 Elsevier B.V. All rights reserved.