Enriched Oxygen Vacancies Bi2wo6-Ov@Ldhs Photoactivated Persulfate Degradation of Tetracycline: Synergistic Effect of Z-Scheme Heterojunction and Variable Valence State

Abstract

Photoactivated persulfate (S2O82−, PS) degradation of pollutants has the characteristics of being green, efficient, and economical. However, due to the limited carrier transport capacity and active sites of the catalyst, there is still a lot of room for improvement in the activation efficiency of PS. In this paper, based on oxygen rich vacancies Bi2WO6-Ov@CoFe-LDHs heterojunction (BWO-Ov@LDHs), which can efficiently activate PS under visible light, BWO-Ov@LDHs/PS material system was fabricated for efficient degradation of tetracycline (TC). After 30 minutes photodegradation, the removal of TC by BWO-Ov@LDHs/PS reached 93.4%, which is 2.9-3.1 times than that of pure PS and BWO-Ov@LDHs. Based on a series of photoelectric performance tests and theoretical calculations such as work function and differential charge density, a synergistic effect of Z-scheme heterojunction, photoactivated persulfate and variable valence state on oxygen rich vacancies is proposed from the perspectives of band structure, built-in electric field, charge transfer, etc. In addition, detailed discussions were conducted on the degradation intermediates, pathways, and the toxicological properties of intermediates.

Keywords: Z-scheme heterojunction, Oxygen Vacancies, photodegradation, Advanced oxidation technology (AOPs), Tetracycline