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

Abstract

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 5nm 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 2h. 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 5nm, 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 (283–323K) 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.