Insights into performance and mechanism of ZnO/CuCo2O4 composite as heterogeneous photoactivator of peroxymonosulfate for enrofloxacin degradation

Abstract

In this study, we designed a plain strategy for fabrication of the novel composite ZnO/CuCo₂O₄ and applied it as catalyst for peroxymonosulfate (PMS) activation to decompose enrofloxacin (ENR) under simulated sunlight. Compared to ZnO and CuCo₂O₄ alone, the ZnO/CuCo₂O₄ composite could significantly activate PMS under simulated sunlight, resulting in the generation of more active radicals for ENR degradation. Thus, 89.2 % of ENR could be decomposed over 10 min at natural pH. Furthermore, the influences of the experimental factors, including the catalyst dose, PMS concentration, and initial pH, on ENR degradation were evaluated. Subsequent active radical trapping experiments indicated that sulfate, superoxide, and hydroxyl radicals together with holes (h⁺) were involved in the degradation of ENR. Notably, the ZnO/CuCo₂O₄ composite exhibited good stability. Only 10 % decrease in ENR degradation efficiency was observed after four runs. Finally, several reasonable ENR degradation pathways were proposed, and the mechanism of PMS activation was elucidated. This study provides a novel strategy by integrating state-of-the-art material science and advanced oxidation technology for wastewater treatment and environmental remediation.

Keywords: Active radicals; Enrofloxacin; Peroxymonosulfate; Reaction mechanism; ZnO/CuCo(2)O(4) composite.