摘要
水污染对生态环境和人类健康造成了巨大危害,特别是水体中抗生素和重金属具有毒性且难生物降解,已经引起科研工作者的广泛关注.传统的水处理技术难以有效地消除这些污染物.近年来,人们致力于开发绿色、低碳且高效的光催化技术用于解决环境污染问题,该技术实现大规模应用的核心在于开发出经济、高效的光催化剂.由于单一半导体光催化材料(如BiOBr)存在一些缺陷(如有限的催化活性位点和光生电子-空穴快速复合等),因此,构建具有可见光响应、高暴露活性位点和强氧化还原能力的异质结特别是新兴的梯(S)型异质结是去除这些污染物的有效策略之一.MIL-101(Fe)是一种新型的可见光驱动的金属-有机配体框架材料,具有强还原活性、高比表面积和较好的可见光吸收能力,因此,将氧化型的Bi OBr与还原型的MIL-101(Fe)进行合理设计,构筑S型异质结,有望开发出高效的催化材料.本文采用溶剂热法成功制备了一种新型的MOF基S型异质结MIL-101(Fe)/BiOBr,用于可见光照射下光催化还原六价铬(Cr(Ⅵ))和降解抗生素恩诺沙星.结果表明,在单一污染物体系中,MIL-101(Fe)/BiOBr可有效还原99.4%的Cr(Ⅵ)和氧化分解84.4%的恩诺沙星.值得注意的是,在Cr(Ⅵ)和恩诺沙星共存的条件下,MIL-101(Fe)/BiOBr对(Cr(Ⅵ))和恩诺沙星的去除效率明显提升,这主要是由于S型催化剂、Cr(Ⅵ)和恩诺沙星之间具有协同效应.MIL-101(Fe)/BiOBr催化剂活性增强的主要因素如下:(1)MIL-101(Fe)提供了大量的活性位点,改善了催化材料的光吸收能力.(2)S型载流子分离路径不但促进了电子和空穴的高效分离,而且增强了体系的氧化还原能力.此外,采用自由基捕获实验、电子自旋共振波谱仪、液相色谱-质谱联用技术以及毒性分析软件,系统分析了光催化反应机理、抗生素分解过程和中间产物的生物毒性.综上,本文提供一种简单有效的策略来构筑高活性的MOF/无机半导体S型异质结材料用于高效净化水体环境.
The development of highly active,economical,and robust bifunctional photocatalysts is a priority for sustainable photocatalytic water remediation.Inadequately available reactive sites and sluggish interface photocarrier transfer and separation remain significant challenges in the photoreaction progress.In this study,the Fe-containing metal-organic framework(MOF)MIL-101(Fe)was integrated with BiOBr microspheres to form a competent S-scheme heterostructure for the photocatalytic mitigation of Cr(VI)and enrofloxacin(ENR)antibiotics.The optimal MIL-101(Fe)/BiOBr exhibited the highest photoactivity,with 99.4%of Cr(VI)and 84.4%of ENR eliminated upon visible-light illumination in a single-pollutant system.The photoactivity of MIL-101(Fe)/BiOBr in the decontamination of the Cr(VI)-ENR co-existence system exhibited a substantial enhancement when compared to that in a single system,owing to the improved utilization of electrons and holes resulting from the synergism between Cr(VI),ENR,and the photocatalyst.The enhanced photoactivity is attributed to two aspects:(1)the incorporation of MIL-101(Fe)results in an increased number of available reactive sites and improved solar harvesting properties;and(2)the S-scheme mechanism enables the effective spatial disassociation of photoexcited carriers and optimization of the photo-redox capability of the system.Through scavenging experiments,electron spin resonance characterization,liquid chromatography-tandem mass spectrometry analysis,and T.E.S.T.theoretical estimation,the catalytic mechanism,antibiotic degradation process,and biotoxicities of the degraded products were analyzed and confirmed.This study provides a viable strategy for building competent MOF-inorganic semiconductor S-scheme photocatalysts with superior photocatalytic decontamination performance.
作者
李世杰
王春春
董珂欣
张鹏
陈晓波
李鑫
Shijie Li;Chunchun Wang;Kexin Dong;Peng Zhang;Xiaobo Chen;Xin Li(Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province,National Engineering Research Center for Marine Aquaculture,College of Marine Science and Technology,Zhejiang Ocean University,Zhoushan 316022,Zhejiang,China;State Centre for International Cooperation on Designer Low‐carbon and Environmental Materials(CDLCEM),School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,Henan,China;Department of Chemistry,University of Missouri‐Kansas City,MO 64110,USA;Institute of Biomass Engineering,Key Laboratory of Energy Plants Resource and Utilization,Ministry of Agriculture and Rural Affairs,South China Agricultural University,Guangzhou 510642,Guangdong,China)
基金
国家自然科学基金(U1809214,51708504)
浙江省自然科学基金(LY20E080014,TGN23E080003)
舟山市科技计划项目(2022C41011).
