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 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 Bronsted 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.