Efficient Fe/CuFeO2/rGO nanocomposite catalyst for electro-Fenton degradation of organic pollutant: Preparation, characterization and optimization

The nanocomposite of zero-valent iron and delafossite CuFeO2 supported on reduced graphene oxide was synthesized for the first time to evaluate its performance as the heterogeneous catalyst toward electro-Fenton (EF) removal of catechol. X-ray diffraction, Fourier transform-infrared, scanning electron microscopy and Brunauer-Emmett-Teller (BET) were used to characterize the nanocomposite. It was found that the rhombohedral structure of CuFeO2 remained stable during the nanocomposite preparation. The BET surface area of the nanocomposite increased about 102 times in comparison with bare CuFeO2. The influence of the operating parameters was investigated. The optimum operating conditions were pH 3, Fe/CuFeO2/rGO: 1 g/l; catechol: 7.5 x 10(-4) mol/l; and I: 150 mA, which led to 99% and 78.4% catechol and chemical oxygen demand removal in 120 min, respectively. The stability of the catalyst by leaching measurements was studied. Only 2% and 3.1% of iron and copper, respectively, was leached in the solution. The obtained results introduced Fe/CuFeO2/rGO as a stable and appropriate catalyst for removal of organic compounds by the EF process. It was inferred from the scavenger utilization that hydroxyl radical plays a major role in catechol elimination and EF reaction followed by the Haber-Weiss mechanism at optimum conditions. The gas chromatography-mass spectrometry analysis was performed to detect the intermediate products, and an acceptable degradation pathway was proposed. The EF degradation of catechol follows a pseudo-first-order kinetics model with a rate constant of 3.69 x 10(-2) min(-1) for the optimum operating conditions. The reusability of Fe/CuFeO2/rGO was investigated for six cycles, and the catalytic efficiency almost remained.