Degradation of nitrobenzene by Fenton-like reaction in a H2O2/schwertmannite system

In this study, schwertmannite was used as heterogeneous Fenton-like catalyst for nitrobenzene degradation in a closed batch system. The properties of catalyst samples were characterized by measuring the specific area (S-BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The catalytic activity was evaluated in view of the effect of various conditions (initial pH value, catalyst dosage, H2O2 concentration). The results showed that the removal efficiency of nitrobenzene was significantly enhanced in the presence of schwertmannite and the catalyst retained almost its high catalytic activity after 5 consecutive runs. The optimum pH value in this study was found to be 3.0 and the optimal concentration of H2O2 was 500 mg/l. The removal of the nitrobenzene could be achieved 92.5% in 30 min at initial conditions. The mechanism of catalytic oxidation was radical mechanism via the catalysis of schwertmannite to form hydroxyl radicals by decomposing H2O2. In addition, nitrophenols were the main transformation products detected by liquid chromatography and mass spectrometric (LC/MS). (C) 2015 Elsevier B.V. All rights reserved.