Activation of peroxymonosulfate with magnetic Fe3O4–MnO2 core–shell nanocomposites for 4-chlorophenol degradation

Heterogeneous catalysts with low cost, little hazardous, high effective and facile separation from aqueous solution are highly desirable. In this study, magnetic Fe 3 O 4 –MnO 2 core–shell nanocomposites with various Fe/Mn weight ratios were synthesized through a facile one pot method and then characterized. These as-synthesized solids were applied to activate the peroxymonosulfate (PMS) for 4-chlorophenol degradation. The sample 3 with a Fe/Mn molar ratio of 4:1, which can be separated conveniently through external magnetic field, exhibited higher activity than other Fe 3 O 4 –MnO 2 nanocomposites, pure MnO 2 and physical mixture of Fe 3 O 4 and MnO 2 . The effects of operational parameters on the catalytic activity of sample 3, including initial Oxone and pollutant dosage, pH and catalyst dosage, were assessed. The catalyst had high stability and good reusability according to five successive repeated reaction. The reactive radicals generated in the PMS/Fe 3 O 4 –MnO 2 nanocomposites system were sulfate radical (SO 4 − ) and hydroxyl radical ( OH). The enhancement of the nanocomposites may be attributed to the interaction of Fe 3 O 4 with MnO 2 on the basis of the in situ ATR-FTIR analysis and XPS spectrum.