Direct Z-scheme covalent triazine-based framework/Bi2WO6 heterostructure for efficient photocatalytic degradation of tetracycline: Kinetics, mechanism and toxicity

Photocatalysis provides a green strategy to eliminate the emerging pollutants of antibiotics. However, it remains challenging to design robust photocatalyst to fulfil the requirement of industrial implementation. Herein, a novel Z-scheme covalent triazine-based framework (CTF)-Bi 2 WO 6 heterojunction photocatalyst was rationally fabricated by interfacial engineering of layered CTF-1 into flower-like Bi 2 WO 6 for photocatalytic removal of antibiotic, using tetracycline (TC) as a representative. The structural, physicochemical, and electrochemical capabilities of the as-prepared photocatalyst were explored in detail by a range of advanced analyses. The results showed that the optimized CTF-Bi 2 WO 6 exhibited superior photocatalytic performance, affording a TC removal efficacy of 77.14 % within 60 min, which was approximately 18 times and 2.67 times that of individual CTF-1 and Bi 2 WO 6 , respectively. The boosting property could be attributed to the Z-scheme heterostructure, which significantly reinforced the transfer and separation of photoinduced carriers. Meanwhile, the dominate reactive species participating in the degradation process were probed as O 2 − and h + based on scavenger experiments and ESR analyses. Finally, the degradation pathway of TC by CTF-Bi 2 WO 6 was proposed based on intermediate products, and the toxicity of TC and its degradation products were estimated by the toxicity estimation software tool (T.E.S.T.). This study showcases a feasible pathway towards designing CTF-based Z-scheme heterojunction photocatalysts for effective and eco-friendly antibiotic wastewater treatment. • A Z-scheme CTF-Bi 2 WO 6 heterostructure photocatalyst was constructed. • CTF-Bi 2 WO 6 displayed superior photocatalytic activity for tetracycline degradation. • The underlying kinetics, mechanism, and degradation pathway were probed. • The toxicity of degradation intermediates was analyzed by T.E.S.T.