Ferric iron enhanced chloramphenicol oxidation in pyrite (FeS2) induced Fenton-like reactions

In this study, the novel combination of Fe3+ and FeS2/H2O2 system was used to enhance the degradation of chloramphenicol (CAP) by promoting the synergetic effect between the Fe3+ and the FeS2, and the kinetic models to elucidate the reaction mechanisms were validated. Raw pyrite samples were pretreated and characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy and Brunauer-Emmett-Teller surface area analyzer. Studies on the effects of buffer solution and phosphate on the kinetics of CAP degradation revealed that the autocatalytic effect was associated with the dissolution and generation of Fe3+. As confirmed by the experiment to examine the Fe3+ mediated oxidation of FeS2, the catalytic improvement was due to the release of Fe2+ by the reaction between the FeS2 and the Fe3+ at zero-order rate when the Fe3+ was excessively present. Kinetic models including surface-controlled activation and homogeneous Fenton reactions were responsible for the degradation of CAP. (C) 2015 Elsevier B.V. All rights reserved.