Insights into the adsorption-assisted PMS activation of Ce-UiO-66-4F in an in situ chemical oxidation process for efficient pollutant removal

Abstract

In this study, a Ce-UiO-66-4F (CU4F) catalyst with an enhanced in situ chemical oxidation (ISCO) process was constructed using tetrafluoroterephthalic acid (TFTPA) as an organic linker and Ce(IV) as a metal center for the degradation of pollutants with electron-donating groups. In the ISCO process, the adsorption resistance of reactants and peroxymonosulfate (PMS) activation were significantly improved owing to the exploration of available active sites provided by the CU4F catalyst with high defect density and a mesopore structure, promoting the mineralization of pollutants by ROSs and the electron transfer process. The CU4F catalyst showed preferential adsorption of sulfamethoxazole (12 times that of caffeine), which triggered the electron transfer pathway and promoted degradation. In addition, CU4F exhibited satisfactory degradation efficiency (>95%) and mineralization (>70%) for pollutants with electron-donating groups (sulfamethoxazole, bisphenol A, and ibuprofen) together with good stability in the sixth cycle and in different water bodies. Moreover, the prepared CU4F-based nanofibrous membranes exhibited good treatment capacity for sulfamethoxazole, bisphenol A, and ibuprofen in the designed dynamic catalytic reactor. This work offers deep insights into the relationship between adsorption and PMS activation in the ISCO process, which is favorable for the rational design of catalysts with enhanced catalytic performance in complicated heterogeneous systems.