Catalytic ozonation of atenolol by Mn-Ce@Al2O3 catalysts: Efficiency, mechanism and degradation pathways

Abstract

The aim of this study is to investigate the degradation efficiency and mechanism of atenolol (ATL) by catalytic ozonation with Al2O3 supported manganese-cerium mixed oxides (Mn-Ce@Al2O3), prepared by the impregnation-calcination method. The Mn-Ce@Al2O3 with 0.2 wt% manganese and 0.2 wt% cerium exhibited superior catalytic performance, resulting in complete ATL degradation and 63% mineralization. Mn-Ce solid solution on the surface significantly increased the specific surface area (279.5 m2/g). High amount of Ce3+, Mn3+ and high density of surface-active oxygen were contained on the surface of the catalyst, which facilitates the formation of oxygen vacancies and promotes the electron transfer in the catalyst. Combined with the low charge transfer resistance, surface protonated hydroxyl group, which was the active site of 0.2Mn-Ce@Al2O3, was more likely to adsorb ozone and decompose it into reactive oxygen species. O2·− and •OH were found to be the dominant active radicals for ATL degradation and mineralization that followed first-order kinetics. 17 intermediates were identified and 3 main degradation pathways were summarized, in order to provide reference for the complete mineralization of ATL.