Here, the substrate decay and mineralization rate for 100 cm(3) of a 2.0 mM phthalic acid solution in 0.10 M Na2SO4 of pH 3.0 have been studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). The electrochemical cell was a stirred tank reactor containing a 3 cm(2) boron-doped diamond (BDD) anode and a 3 cm(2) air-diffusion cathode that generates H2O2. Cu2+ and/or Fe3+ were added as catalysts with total concentration of 0.50 mM and a constant current density of 33.3 mA cm(-2) was applied. In EF with Cu-2* or Fe3+ alone and SPEF with only Cu2+, phthalic acid decayed slowly and poor mineralization was reached because the main oxidant was (OH)-O-center dot produced at the BDD surface from water oxidation. In contrast, the substrate destruction was largely enhanced using SPEF with 0.50 mM Fe3+ since a high quantity of oxidant (OH)-O-center dot was produced in the bulk induced by photo-Fenton reaction. This treatment led to an almost total mineralization by the photolysis of generated Fe(III)-carboxylate complexes. In all cases, the decay of phthalic acid obeyed a pseudo-first-order reaction. The combination of Cu2+ and Fe-3* as catalysts accelerated the mineralization process in SPEF because Cu(II)-carboxylate complexes were also removed with (OH)-O-center dot formed from photo-Fenton reaction. The best SPEF process was found for 0.125 mM Cu2+ +0.375 mM Fe3+, giving rise to 99% mineralization with 40% current efficiency and 0.294 kWh g(-1) TOC energy consumption. Eleven aromatics and six short-linear carboxylic acids were identified as oxidation products. A plausible reaction sequence for phthalic acid mineralization involving all the detected products was finally proposed. (C) 2013 Elsevier Ltd. All rights reserved.