Enriched oxygen vacancies Bi₂WO₆-Ov@LDHs photoactivated persulfate degradation of tetracycline: synergistic effect of Z-scheme heterojunction and variable valence state

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 band structure, XPS result and theoretical calculations such as work function and differential charge density, it indicates that the Z-scheme heterojunction accelerates the transfer and conversion of electrons, and the activation of persulfate ions generates sulfate radicals, enhancing the photocatalytic performance, the variable valence state further strengthens the generation of sulfate radicals, and the tripartite synergy promotes the efficient photocatalytic degradation of TC. The results based on LC-MS provided the intermediate products and pathways of the degradation process, while toxicity analysis showed that the toxicity of intermediate products was lower.