This study evaluated the performance of photo-Fenton reaction when it was initiated by using UV/H2O2 with steel waste, basic oxygen furnace slag (BOF slag), denoted as UV/H2O2/BOF slag process, to decompose 2-naphthalenesulfonate (2-NS) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the decomposition of 2-NS by the UV/H2O2/BOF slag process. A first-order kinetic model with respect to TOC was appropriately adopted to represent the mineralization of 2-NS by the UV/H2O2/BOF slag process. The experimental results of this study suggested that the dosages with 1.25 x 10(-4) mol L-1 min(-1) H2O2 and 12.5 g L-1 BOF slag loading in the solution at pH 2.5 with 120 mu W cm(-2) UV (312 nm) provided the optimal operation conditions for the mineralization of 2-NS yielding a 56% mineralization efficiency after 90 min of reaction time. (c) 2006 Elsevier B.V. All rights reserved.