In-situ dispersing ultrafine Fe2O3 nanoparticles in mesoporous silicas for efficient peroxymonosulfate-activated degradation of tetracycline over a broad pH range

The supported ultra-small Fe2O3 nanoparticles, as conventional functional materials for versatile applications, are scarcely investigated for their catalytic properties in peroxymonosulfate-activated reactions to deal with the ever-growing environment issues. In this work, highly dispersed ultrafine Fe2O3 nanoparticles are successfully generated in framework of mesoporous silicas (such as Fe/Si-3, with 3.01 wt% of Fe content) through an in-situ approach with iron phthalocyanine as Fe source. The formation of Fe-N or Fe-C bonds exerted remarkable isolation effect on the generation of the nanoparticles. Fe/Si-3 gave superior activity to other Fe catalysts analogs including bulk Fe2O3 in peroxymonosulfate-triggered degradation of tetracycline. Fe/Si-3 has a wide working pH window of 3-11. It can be recycled for 3 times without significant loss of the degradation activity. The radicals of SC4 center dot-, center dot OH, O-2(center dot-) and O-1(2) all contributed to the degradation reaction. The factors for high degradation efficiency and broad working pH range of Fe/Si-3, the mechanism for formation of various radicals, as well as the transformation pathway of tetracycline molecules were proposed.

Automated summary

This study successfully prepared highly dispersed ultrafine Fe2O3 nanoparticles, which exhibited superior catalytic activity in the framework of mesoporous silicas and showed a wide working pH range in peroxymonosulfate-triggered degradation reactions.