Superior sulfate radicals-induced visible-light-driven photodegradation of pharmaceuticals by appropriate ce loading on fibrous silica ceria

Abstract

atterly, sulfate radical (SO4-)-based advanced oxidation processes (SR-AOPs) have earned great attention for wastewaters treatment containing antibiotics with provides SO4- as an active species. In this study, fibrous silica-ceria (FSC) with various Ce loadings (Ce wt%) were successfully synthesized via microemulsion-crystallization. The catalysts' behaviour was evaluated by XRD, FESEM, N2 adsorption/desorption, UV-vis DRS, FTIR, PL and ESR. Results proved that tuning the Ce wt% influenced the crystallinity, particle size, surface defect, oxygen vacancies as well as band gap of FSCs, which altered their properties toward sulfate radical generation in enhancing the photodegradation performances. Photodegradation of ciprofloxacin (CIP) using catalysts in the presence of peroxydisulfate (PDS) are in the following order: FSC-0.1 (92 %) > FSC-0.15 (85 %) > FSC-0.05 (76 %) > commercial CeO2 (37 %) under visible light for 240 min. Radical scavenging and ESR spin-trapping experiment revealed that the induced sulfate radicals (SO4-) and hydroxyl radicals (OH) during reaction had accelerated the performance of CIP degradation. Besides, a detailed energy diagram of CeO2 and FSC-0.1 was proposed based on VB XPS and Tauc plots. This work indicated that the FSC-0.1 coupled with PDS retained its efficiency for five-cycles of reaction without any significant-loss and displayed promising applications for the various pharmaceutical compounds (PCs).