Ceria accelerated nanoscale zerovalent iron assisted heterogenous Fenton oxidation of tetracycline

Abstract

The development of an ultra-efficient heterogeneous Fenton catalyst that has practical application and can be easily separated is of great importance. In this study, a novel nanocomposite, Fe0/CeO2, was successfully synthesised and applied for Fenton oxidation of tetracycline. The results show that Fe0/CeO2 significantly enhanced the removal of pollutants, which suggests a synergistic effect between nanoscale zero-valent iron and CeO2. Furthermore, the composite catalyst exhibited ideal reusability and wide pH adaptation. A radical identification experiment revealed that surface-bounded OH (OHads) played a critical role in Fenton reaction, and compared with bare nanoscale zero-valent iron, Fe0/CeO2 remarkably promoted the generation of OH in the Fenton system, mostly because CeO2 not only increased the adsorption properties of the catalyst, it also accelerated electron transfer to promote the decomposition of H2O2 due to the abundance of surface oxygen vacancies. A reasonable degradation pathway was also proposed for tetracycline on the basis of the detected intermediates. Our findings help to understand the mechanism of tetracycline degradation by heterogeneous Fenton-like, and also provide an efficient system for organic wastewater treatment.