Removal of aniline from water by an Fe(II)-nano-Fe3O4@PAC heterogeneous catalyst in a Fenton-like process

Aniline is a toxic chemical, and in many industries it is degraded by Fenton processes. In this study, an Fe(II)-nano-Fe3O4@PAC heterogeneous Fenton catalyst (MFC) was prepared with a coprecipitation and impregnation method, which is simple, efficient and cost effective. The results of the magnetic performance tests showed that the MFC has typical ferromagnetism properties. Nano-Fe3O4 was found both on the surface and inside the pores of the powdered activated carbon (PAC). MFC was found to be an efficient catalyst in the Fenton-like process for aniline degradation. The optimal conditions were obtained by the orthogonal experimental method. The results showed that under the optimal conditions (pH = 3.00, temperature = 20°C, concentration of MFC = 1.0 g/L, concentration of H2O2 = 0.27 g/L), the 5 mg/L aniline solution degradation ratio reached 91.2% and the mineralization ratio reached 75.77% in 30 min. In addition, kinetics studies indicated that the aniline degradation process follows a pseudo-first-order kinetics model. No refractory intermediate such as azobenzene, was found during the reaction. The pH value is an important factor in aniline solution degradation. This result indicates that in addition to the surface catalytic reaction, the Fenton reaction also occurs in solution. Fe2+/Fe3+ on the MFC surface and Fe2+/Fe3+ in solution both affect aniline degradation. This catalyst has the advantage of being easily magnetically separated from the aqueous phase. It has useful application prospects in solving organic industrial wastewater pollutions in developing countries because of its cost-effectiveness.