Recyclable Fenton-like catalyst based on zeolite Y supported ultrafine,highly-dispersed Fe2O3 nanoparticles for removal of organics under mild conditions

A versatile wet impregnation method was employed to conveniently and controllably deposit Fe₂O₃ nanoparticles on zeolites including commercial Y, mordenite and ZSM-5 with the similar framework Si/Al ratios and crystal sizes, respectively. The ultrafine Fe₂O₃ nanoparticles in size of 5 nm can be highly dispersed on zeolite Y matrix due to its much better wettability than ZSM-5 and mordenite. By using the obtained Fe₂O₃/zeolite composite as the heterogeneous Fenton-like catalysts, the degradation of phenol as a model reaction was systematically investigated, including the zeolite supports, particle size and dispersion of Fe₂O₃, and reaction conditions of H₂O₂ concentration, temperature, and pH value. The catalyst based on zeolite Y with Fe loading of 9% exhibited the best phenol degradation efficiency (> 90%) in neutral pH within 2 h. Its high catalytic activity in Fenton reaction can be attributed to the bifunctional properties of strong surface Brønsted acidity and high reactivity of octahedral Fe³⁺ in the highly-dispersed ultrafine Fe₂O₃ nanoparticles in size of 5 nm, which were the primary active centers to quickly decompose H₂O₂ into hydroxyl radicals. Since phenol degradation can be performed under mild conditions of ambient temperature (283–323 K) and a wide pH range (4.0–7.0), the catalysts can be easily recovered for recyclable use with stable degradation activity, which own the immense potential in deep treatment of organic pollutants in industrial wastewater.