Photocatalytic removal of tetracycline by a Z-scheme heterojunction of bismuth oxyiodide/exfoliated g-C3N4: performance, mechanism, and degradation pathway. (March 2022)

• Record Type: Journal Article
• Authors: Liu, Hui; Huo, Wangchen; Zhang, Tian C.; Ouyang, Like; Yuan, Shaojun
• Is Part Of: Materials today chemistry. Volume 23(2022)
• Publication Date: 2022-03
• Subjects: Z-scheme heterojunction -- BiOI -- g-C3N4 -- Photocatalysis -- Tetracycline degradation; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2021.100729
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: Antibiotics, once being released into the environment, become recalcitrant organic pollutants, which pose a potential risk to ecological balance and human health. In this study, a Z-scheme heterojunction of bismuth oxyiodide (BiOI)/exfoliated g-C3 N4 (BiOI/ECN hereafter) was synthesized by the combination of thermal exfoliation of g-C3 N4 and chemical precipitation of BiOI for efficient photocatalytic degradation of tetracycline in aqueous solutions under visible light irradiation. The optimized BiOI/ECN delivered an outstanding degradation rate at circa 0.0705 min −1, which was 10 times higher than that of the bulk g-C3 N4 . The photocatalytic degradation efficiency of tetracycline remained almost unchanged in a pH range of 3–11, and the BiOI/ECN displayed an excellent photostability upon recycled usage. The photocatalytic mechanism of tetracycline was ascribed to the main reactive oxidation species of photogenerated holes and superoxide radicals. In addition, the possible degradation pathways of tetracycline were investigated by HPLC-MS to identify intermediates. The toxicity of photocatalytic-generated intermediates of tetracycline was found significantly alleviated according to the calculation of quantitative structure–activity relationship prediction. This work not only provides an attractive photocatalyst for the removal of tetracycline but also opens a new avenue for rational design of Z-scheme heterojunction composites for tetracycline degradation. Graphical abstract: Image 1 Highlights: A novel Z-scheme heterojunction of bismuth iodide oxide (BiOI)/exfoliated g-C3 N4 (ECN) was successfully fabricated. The BiOI/ECN photocatalyst delivered high photocatalytic degradation of tetracycline under visible light irradiation. The BiOI/ECN photocatalyst exhibited excellent photoelectric effect and high photostability. The photocatalytic degradation mechanism was verified by density functional theory simulation and electron spin resonance characterization. The toxicity of photocatalytic-generated tetracycline intermediates was evaluated by the quantitative structure–activity relationship calculation.