Magnetic Nanoscaled Fe3O4/CeO2 Composite as an Efficient Fenton-Like Heterogeneous Catalyst for Degradation of 4-Chlorophenol

Magnetic nanoscaled Fe3O4/CeO2 composite was prepared by the impregnation method and characterized as a heterogeneous Fenton-like catalyst for 4-chlorophenol (4-CP) degradation. The catalytic activity was evaluated in view of the effects of various processes, pH value, catalyst addition, hydrogen peroxide (H2O2) concentration, and temperature, and the pseudo-first-order kinetic constant of 0.11 min(-1) was obtained for 4-CP degradation at 30 degrees C and pH 3.0 with 30 mM H2O2, 2.0 g L-1 Fe3O4/CeO2, and 0.78 mM 4-CP. The high utilization efficiency of H2O2, calculated as 79.2%, showed a promising application of the catalyst in the oxidative degradation of organic pollutants. The reusability of Fe3O4/CeO2 composite was also investigated after six successive runs. On the basis of the results of metal leaching, the effects of radical scavengers, intermediates determination, and X-ray photoelectron spectroscopic (XPS) analysis, the dissolution of Fe3O4 facilitated by CeO2 played a significant role, and 4-CP was decomposed mainly by the attack of hydroxyl radicals (center dot OH), including surface-bound center dot OHads generated by the reaction of Fe2+ and Ce3+ species with H2O2 on the catalyst surface, and center dot OHfree in the bulk solution mainly attributed to the leaching of Fe.