Persulfate activation by magnetic γ-Fe2O3/Mn3O4 nanocomposites for degradation of organic pollutants

Abstract

Abstract In this work, magnetic γ-Fe2O3/Mn3O4 nanocomposites with various mass ratios were successfully fabricated using a facile two-step method. Then these composites were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microcopy (TEM), X-ray photoelectron spectra (XPS) and vibrating sample magnetometer (VSM) measurements. Besides, the samples were applied to activate persulfate for Rh B degradation. Results showed that the sample with a γ-Fe2O3/Mn3O4 mass ratio of 3:1 exhibited higher activity than other γ-Fe2O3/Mn3O4 nanocomposites, pure γ-Fe2O3 and pure Mn3O4, where 95.1% of Rh B could be decomposed within 150 min in the presence of persulfate. In addition, effects of operational parameters on the catalytic activity of Rh B were also evaluated, which included persulfate concentration, catalyst dosage, reaction temperature and initial pH value. More importantly, the as-fabricated γ-Fe2O3/Mn3O4 nanocomposites revealed magnetism and could be separated conveniently through external magnetic, which was beneficial to recycle the catalysts from the aqueous solution. Finally, the mechanism of activating persulfate by γ-Fe2O3/Mn3O4 nanocomposites was proposed based on the results and literatures, which might provide a reference for further study of heterogeneous catalysis.