Heterogeneous catalytic wet peroxidation (CWPO), involving the mineralization (i.e. complete conversion to CO2 and H2O) of organic compounds is a possible path for the treatment of toxic and/or bio-refractory wastewater streams. The aim of the present work was to synthesize and characterize five solid-phase catalyst formulations featuring iron(III) species supported on silica-based mesoporous molecular sieves of the MCM-41 and HMS-types. These materials were tested for the CWPO of aqueous phenol in a batch slurry reactor using hydrogen peroxide, as an oxidant, under very mild conditions (P = 1 atm and T = 80degreesC). The five materials were produced according to four recipes. Structural data was provided by XRD and nitrogen adsorption-desorption, the iron content was assessed by atomic absorption. The freshly obtained catalysts, with embedded templates within pores, were activated either by calcination or through solvent extraction, then used for CWPO. The spent catalysts were recovered and characterized before thermal re-activation and re-exposure to fresh phenol-containing solutions. For all materials, in the first run, the conversion of phenol was total and rapid (less than 15 min), and the removal of total pollution plateaued between 55 and 85% in 180 min with mineralization selectivities of ca. 95%. The materials underwent leaching of the iron, from 6% (w/w) to total. It was possible to perform successful CWPO reactions with some recycled materials. In terms of activity as well as robustness in the reaction conditions, one catalyst was able to remove 81% of the organic load with a selectivity of 93%, and simultaneously leaching 6% iron off. During the second run, it showed less activity but endured 2% leaching only. Surprisingly, the structure of this best catalyst was not mesoporous nor microporous and exhibited a very low specific surface area. (C) 2003 Elsevier B.V. All rights reserved.