Treatment of Phenolic Effluents by Catalytic Wet Hydrogen Peroxide Oxidation over Fe2O3/SBA-15 Extruded Catalyst in a Fixed-Bed Reactor

Abstract

Iron oxide supported over mesostructured SBA-15 material (Fe2O3/SBA-15) has been used in a fixed-bed reactor (FBR) for the catalytic wet hydrogen peroxide oxidation (CWHPO) of phenolic aqueous solutions. This catalyst is agglomerated by extrusion with different particle sizes (0.35−2 mm) using bentonite mineral clay and methyl cellulose as inorganic and organic binders, respectively. Several variables, such as the feed flow rate, the weight of the catalyst bed, and the particle size, have been studied in order to optimize the operation conditions for phenol mineralization. Activity of catalyst in terms of phenol degradation and TOC reduction has been monitored. Internal diffusional problems by the increase of the particle size seem not to play a dominant role in the overall catalytic performance. Loadings of catalysts higher than 2.9 g for 1 cm3/min of 1 g/L phenolic aqueous solution, equivalent to residence times ≈ 3.1−3.8 min, have not substantially affected the phenol and TOC reduction. Under the best operation conditions, complete phenol degradation and remarkable TOC conversion (ca. 66%) have been achieved at steady-state conditions. The role of Fe2O3/SBA-15 catalyst as compared to a homogeneous catalytic system and the long-term activity of the heterogeneous catalyst have been also demonstrated for the continuous treatment of an aqueous phenolic solution.