Heterogeneous photocatalytic ozonation of sulfamethoxazole by Z-scheme Bi2WO6/TiO2 heterojunction: Performance, mechanism and degradation pathway

The objective of this study was to investigate the performance of Bi2WO6/TiO2 (BT) heterojunction for photocatalytic ozonation degradation and the mineralization of sulfamethoxazole (SMX) under simulated sunlight. The authors investigated the effects of the Bi2WO6 and TiO2 ratio, as well as the catalyst dosage, ozone concentration, initial SMX concentration, pH value, and inorganic ions on the degradation efficiency of SMX in the BT photocatalytic ozonation process. The BT composites were characterized by methods such as XRD, SEM-EDS, TEM, XPS, FT-IR, UV-Vis DRS and BET. When the dosage of BT was 0.2 g/L, the ozone concentration was 1.5 mg/L, the SMX concentration was 10 mg/L, and the pH was 5.25, the removal rate of SMX could reach 97.1% after 180 min of reaction. Under the same conditions, the removal rate of TOC could reach 89.8% when the reaction time was 420 min. Test results after five cycles of experiments showed BT had excellent recyclability and stability. This paper presents a new Z-scheme transfer pathway of electrons and degradation mechanism based on the results of radical trapping experiments and electron spin resonance (ESR) measurements, as well as optical and photoelectrochemical analyses.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the performance of Bi2WO6/TiO2 heterojunction for photocatalytic ozonation degradation and mineralization of sulfamethoxazole under simulated sunlight. The BT composites show high degradation efficiency and excellent recyclability and stability.