Fabricating S-scheme BiOBr/Zn2In2S5 heterojunction for synergistic adsorption-photocatalytic degradation of tetracycline

Harnessing affordable photocatalysts with high performance for boosting charge separation is an effective strategy to reinforce wastewater contaminant control. Herein, we reported a self-assembled S-scheme heterostructure BiOBr/Zn2In2S5 (BZS) nanoflower with the formation of internal electric field to promote the synergistic effect of adsorption and photocatalysis. The result showed that 7 wt% BiOBr/Zn2In2S5 (BZS-7) has highest tetracycline (TC) adsorption capacity of 34.85 mg g−1, which was fitted well the pseudo-second-order and Langmuir isotherm models. Then the synergistic degradation rate could reach 97.52% after 40 min visible light irradiation, which was 1.34 times higher than that of Zn2In2S5. BZS-7 also performed excellent adsorption-photocatalytic synergy on the removal of TC in simulated seawater and continuous flow reactor, with removal efficiency about 81.11% and 34.35%, respectively. The improved performance could be attributed to unique structures and high exposure surface of reassembled morphologies after the introduction of BiOBr. The antibacterial activity and ecotoxicity evaluation of TC intermediate byproducts indicated that the proposed degradation pathways presented reduced acute and chronic toxicity. The synergistic process of cost-effective S-scheme heterojunction photocatalysts holds the research for practical on-site wastewater remediation.