Development of Fe2O3-kaolin catalyst for the removal of enoxacin antibiotic with heterogeneous electro-fenton method

In this study, preparation of a heterogeneous catalyst to use in electro-Fenton process, one of the advanced oxidation processes and the activity of the prepared catalyst in the removal of enoxacin, a fluoroquinolone antibiotic, from water were investigated. For this purpose, Fe2O3-modified kaolin (Fe2O3-KLN) was synthesized as a heterogeneous catalyst. The study was carried out in 3 main parts to understand the effectiveness of the catalyst in the electro-Fenton method. In the first part, the oxidation and mineralization of enoxacin was investigated by using homogeneous electro-Fenton method. In this section, the effect of the electrode type, applied current, amount of Fe3+ and supporting electrolyte on the enoxacin removal were examined. In the second part, the Fe2O3-KLN catalyst was synthesized and its effect on enoxacin removal by the electro-Fenton method was investigated. The prepared heterogeneous catalyst (Fe2O3-KLN) was characterised by SEM / EDX, XRD, BET and AAS analyzes. The aromatic, aliphatic and inorganic products, formed during the oxidation of enoxacin, have been determined by GC-MS, LC-MS and IC analysis. An oxidation pathway was proposed for the mineralization of enoxacin. In addition, the stability and reusability of the catalyst were investigated. At the final stage of the study, the efficiency of the homogeneous and heterogeneous electro-Fenton method on enoxacin removal was compared. The oxidation and mineralization rate of enoxacin were faster in the heterogeneous system than in the homogeneous system. The heterogeneous electro-Fenton system has advantages over homogenous electro-Fenton process such as large working pH range, recovering and recycling of the catalyst, high oxidizing power and low cost. Keywords: Enoxacin, Electro-Fenton, Iron (III) oxide, Hydroxyl radical, Heterogeneous catalysis, Kaolin.