Intensified-Fenton process for the treatment of phenol aqueous solutions

Abstract

An intensified-Fenton process for the treatment of phenol aqueous solutions has been studied as a continuous catalytic wet hydrogen peroxide oxidation system. This process consists of coupling the catalytic activity of a heterogeneous Fenton-like catalyst with the homogeneous contribution of its dissolved iron species. Agglomerated mesoporous SBA-15 silica-supported iron oxide (Fe₂O₃/SBA-15) material was used as heterogeneous catalyst. The influence of the reaction temperature and the initial hydrogen peroxide dosages was studied in order to minimize the operation cost of the process. The catalytic performance of the process was assessed in terms of total organic carbon (TOC) and hydrogen peroxide conversions. Likewise, the stability of the solid Fenton-like catalyst was also evaluated in terms of the dissolved iron species. The increase of the reaction temperature enhanced the TOC conversion and reduced the iron leaching from the heterogeneous catalyst. These results were related to the degradation of oxalic acid as responsible for iron extraction by formation of soluble stable iron complexes into the aqueous medium. Finally, the use of a moderate hydrogen peroxide concentration (2.6 g/L) and milder temperatures (80-120 °C) has led to remarkable results of TOC and phenol reductions as well as oxidant efficiency through the intensified-Fenton process.