Ceria accelerated nanoscale zerovalent iron assisted heterogenous Fenton oxidation of tetracycline

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 (OH_ads) 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. Copyright © 2019 Elsevier B.V. All rights reserved.