Boosted photocatalytic antibiotic degradation performance of Cd0.5Zn0.5S/carbon dots/Bi2WO6 S-scheme heterojunction with carbon dots as the electron bridge

• Published in: Separation and purification technology Vol. 300; p. 121892
• Main Authors: Cai, Mingjie, Wang, Chunchun, Liu, Yanping, Yan, Ruyu, Li, Shijie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2022
• Subjects: Cd0.5Zn0.5S/carbon dots/Bi2WO6; Degradation pathways; PPCPs degradation; S-scheme heterojunction; Toxicity assessment; Cd0.5Zn0.5S/carbon dots/Bi2WO6; Toxicity assessment; Degradation pathways; S-scheme heterojunction; PPCPs degradation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.121892

A novel carbon dots mediated S-scheme heterojunction photocatalyst of CZS/CDs/BWO was finely synthesized by simultaneously integrating S-scheme heterostructure construction and carbon dots decoration strategy and demonstrated highly efficient visible-light photocatalytic elimination of pharmaceutical antibiotics. [Display omitted] •A novel ternary CZS/CDs/BWO S-scheme heterojunction was designed.•S-scheme heterojunction combined with carbon dots achieved efficient carrier disintegration and strong redox capacity.•CZS/CDs/BWO demonstrated robust photocatalytic performance towards PPCPs degradation.•The mechanism and driving power of charge migration and detachment in photoreaction were discussed.•The degradation pathways of TC and the effective detoxification were confirmed. Building high-performance and robust S-scheme heterojunction photocatalysts for sustainable pollutant abatement has been a prospective tactics to restore environment. Herein, Cd0.5Zn0.5S/carbon dots/Bi2WO6 (CZS/CDs/BWO) S-scheme heterojunctions have been designed and fabricated as an efficient and durable visible-light-responsive photocatalyst for tetracycline oxidation with 0.7-fold, 6.4-fold and 0.5-fold enhancement compared with neat CZS, BWO and CZS/BWO. The superb photo-activity is primarily derived from the synergy between carbon dots and S-scheme heterojunction, which not only effectively diminishes the interface resistance but also achieves the fostered disintegration and preservation of the photo-carriers with great redox ability. The impact of water conditions on the photo-activity is explored in view of the complexity of the authentic aquatic environment. The findings of the scavenging tests and ESR analysis evidence that h+, O2−, and OH may mainly drive the antibiotic decomposition, mineralization and detoxification reaction. The photoreaction mechanism and TC degradation pathway over CZS/CDs/BWO are unraveled according to LC–MS analysis. The intermediate toxicity assessment indicates that most of the degradation byproducts’ acute and developmental toxicities are abated to a markedly lower level than that of TC. Moreover, CZS/CDs/BWO also could effectively degrade other popular pharmaceutical antibiotics (e.g., levofloxacin, norfloxacin, oxytetracycline, and enrofloxacin), demonstrating its universal photocatalytic potency for the treatment of pharmaceutical antibiotics. This work illustrates the potential practicability on carbon dots modulated S-scheme heterojunction photocatalysts for efficient water remediation.