Advanced oxidation processes (AOPs) have been developed as an emerging technology for treating hazardous organics in wastewater and groundwater. In the present study, the effect of oxidants [peroxomonosulphate (PMS) and peroxodisulphate (PDS)] on the photocatalytic oxidation of phenol on illuminated TiO2 surfaces has been investigated. The efficiencies of these oxidants on photocatalytic degradation of phenol are compared with that of H2O2. The experimental results indicate that these oxidants exhibited enhanced rates of mineralization of phenol. A reaction mechanism, involving the generation of both hydroxyl radicals and sulphate radicals, was proposed. (c) 2007 Elsevier B.V. All rights reserved.