工业水处理 ›› 2022, Vol. 42 ›› Issue (11): 84-93.

• 试验研究 • 上一篇    下一篇

g-C3N4的制备及其光催化降解诺氟沙星的机理及产物毒性研究

田倩1,2(), 吕勇3, 李晨光1,2, 张延蕾1,2, 李锋民1,2,4()   

  1. 1. 中国海洋大学环境科学与工程学院,近海环境污染控制研究所,山东 青岛 266100
    2. 中国海洋大学海洋环境与生态教育部重点实验室,山东 青岛 266100
    3. 中海油天津 化工研究设计院有限公司,天津 300131
    4. 青岛海洋科学与技术试点国家实验室,海洋生态与环境科学功能实验室,山东 青岛 266071
  • 收稿日期:2022-07-30 出版日期:2022-11-20 发布日期:2022-11-23
  • 作者简介:

    田倩(1995— ),硕士。E-mail:

    李锋民,博士,教授,博导。E-mail:

  • 基金资助:
    国家重点研发计划项目(2018YFC0406300); 山东省重大科技创新工程项目(2018CXGC0304)

Preparation of g-C3N4 and its photocatalytic degradation mechanism of Norfloxacin and product toxicity evaluation

Qian TIAN1,2(), Yong LÜ3, Chenguang LI1,2, Yanlei ZHANG1,2, Fengmin LI1,2,4()   

  1. 1. Institute of Coastal Environmental Pollution Control,College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China
    2. Key Laboratory on Marine Environment and Ecology of Ministry of Education,Ocean University of China,Qingdao 266100,China
    3. CenerTech Tianjin Chemical Research and Design Institute Co. ,Ltd. ,Tianjin 300131,China
    4. Marine Ecology and Environmental Science Laboratory,Pilot National Laboratory for Marine Science and Technology,Qingdao 266071,China
  • Received:2022-07-30 Online:2022-11-20 Published:2022-11-23

摘要:

为探究类石墨相氮化碳(g-C3N4)在不同光源下光催化降解诺氟沙星(NOR)的途径、机理与NOR在降解过程中的毒性变化,以尿素为前驱体合成了g-C3N4纳米片,对其晶型结构和表面形貌进行了表征,对其光吸收性能进行了测试,并通过降解实验考察了g-C3N4纳米片在模拟阳光和可见光下对NOR的降解性能,之后通过猝灭实验、电子顺磁共振技术(EPR)和HPLC-MS手段分析了模拟阳光和可见光下g-C3N4纳米片光催化降解NOR过程中的主要活性物种和中间产物,并采用毒性评估软件工具(T. E. S. T)预测NOR降解产物的毒性。降解实验显示,在模拟阳光照射40 min和可见光照射150 min后g-C3N4分别可去除97%和57%的NOR。猝灭实验和EPR结果显示,模拟阳光下·OH、O2 ·-、h+皆参与降解过程,其中O2 ·-占主导作用;可见光下NOR的降解也主要源于O2 ·-的氧化作用。通过HPLC-MS测定,在模拟阳光和可见光下分别鉴定出20、11种降解产物。依据产物结构分析可得,NOR在2种光源下的降解均涉及到脱氟、脱羧、哌嗪环转化和喹诺酮环裂解4种机理。毒性评估结果显示,NOR经降解后急性毒性和生物蓄积毒性降低,但发育毒性和致突变毒性有所升高,即NOR经光催化降解后仍存在一定的环境风险,需引起关注。

关键词: 诺氟沙星, g-C3N4, 光催化, 降解机理, 毒性评估

Abstract:

In order to understand the pathway and mechanism of the photocatalytic degradation of norfloxacin(NOR)and toxicity changes of NOR during degradation by graphitic carbon nitride(g-C3N4) under different light sources,g-C3N4 nanosheets were synthesized using urea as precursor. The crystal structure and surface morphology were characterized,and the light absorption properties were tested. The degradation performance of g-C3N4 nanosheets for NOR under simulated sunlight and visible light was investigated through degradation experiments. The major reactive species and products of photocatalytic degradation of NOR by g-C3N4 nanosheets under simulated sunlight and visible light were analyzed by quenching experiments,EPR,and HPLC-MS. Toxicity estimation software tool(T. E. S. T) was used to predict the toxicity of NOR degradation products. The degradation experiment showed that,g-C3N4 could remove 97% and 57% of NOR after 40 min of simulated sunlight and 150 min of visible light irradiation,respectively. The quenching experiments and EPR results showed that ·OH,O2 ·- and h+ were all involved in the degradation process under simulated sunlight,and O2 ·- was the major reactive species. The degradation of NOR under visible light was also mainly due to the role of O2 ·-. Through HPLC-MS determination,20 and 11 kinds of degradation products were identified under simulated sunlight and visible light,respectively. According to the product structure analysis,the degradation of NOR under two light sources involved four mechanisms including defluorination,decarboxylation,piperazine ring conversion and quinolone ring cracking. The toxicity assessment results showed that the acute toxicity and bioaccumulation toxicity of NOR after degradation were reduced,but the developmental toxicity and mutagenicity were increased. After photocatalytic degradation of NOR,there were still certain environmental risks,which needed to be concerned.

Key words: norfloxacin, g-C3N4,photocatalysis, degradation mechanisms, toxicity assessment

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