锰氧化物在去除典型抗生素药物中的应用研究
文献类型：学位论文
| 作者 | 李媛 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 魏东斌 |
| 关键词 | 左氧氟沙星 阿莫西林 二氧化锰 高锰酸钾 氧化 机理 毒性 Levofloxacin amoxicillin oxidation genotoxicity mechanism |
| 其他题名 | Applied Research of Removing Typical Antibiotic Drugs by Manganese Oxides |
| 学位专业 | 环境工程 |
| 中文摘要 | 近年来由于抗生素药物的大量生产和使用，终将通过多种途径进入环境，诱导环境中耐药菌的产生，对人类健康和生态环境造成巨大威胁，引起了社会各界的广泛关注。本文，选择两种广泛使用、环境中检出频率高的典型抗生素——左氧氟沙星与阿莫西林作为目标化合物，探讨其在高锰酸钾预氧化处理过程及锰氧化物催化氧化等过程中的转化机理及毒性变化特征，为揭示此类抗生素在环境中的迁移转化规律、潜在风险评价和管理奠定基础，并为其在废水处理、污染土壤修复过程中高效去除技术的研发和工艺参数的优化提供参考。开展的主要研究工作如下： 本文以土壤/沉积物中普遍存在且具有较强氧化活性的锰氧化物δ-MnO2为研究对象，采用湿法制备了δ-二氧化锰，并对其进行了表征，探讨了左氧氟沙星在水-锰氧化物体系中的去除特征，鉴定了转化产物，推导了转化机理，并跟踪监测了毒性变化。本研究选定的δ-MnO2是自然界中含量最多的一种锰氧化物，具有比表面积大，氧化能力强，pHzpc低，阳离子交换容量高等优势，研究了不同二氧化锰当量、不同反应时间对氧化转化过程的影响；利用UPLC-MS分离、识别转化产物，在反应体系中鉴定出10种产物；并提出合理的转化路径，反应机理主要涉及氧化与脱烷基化反应等类型。同时，通过搭建毒性测试平台，对左氧氟沙星催化转化过程的遗传毒性、抗菌活性进行了检测。SOS/umu遗传毒性测试结果显示随着体系中左氧氟沙星的去除，遗传毒性效应也明显降低，且与左氧氟沙星剩余浓度呈良好线性相关性，提示体系的遗传毒性效应主要由母体哌嗪环所致。E.Coli抗菌活性测试结果显示反应体系的抗菌活性仅在高剂量的二氧化锰或长时间反应的条件下显著下降，提示体系的抗菌活性主要由母体氟喹诺酮主环所致。本研究的成果可为废水处理、污染土壤修复技术的研发提供科学依据。 同时，本文还研究了左氧氟沙星在高锰酸钾体系中的氧化转化行为。结果表明，左氧氟沙星在高锰酸钾体系中可以快速降解，高锰酸钾的高投加量和低pH值均有利于左氧氟沙星的转化。转化体系中共分离鉴定出9种主要转化产物，结合有机化学反应原理，分别提出了左氧氟沙星在酸性、中性、碱性条件下的转化路径，机理涉及脱烷基、氧化等多种反应。反应体系的遗传毒性效应测试结果机制与二氧化锰体系相似，均有明显降低趋势。本研究的成果可为高浓度氟喹诺酮类抗生素降解去除技术的研发提供科学依据。 此外，本文还进行了抗生素阿莫西林在二氧化锰氧化体系中的转化机制研究。本研究发现在6d 100当量下δ-MnO2对阿莫西林去除率高达80%，共生成4种主要转化产物，其反应主要活性位点位于四元杂环与苯环上，降解机理主要包括开环、氧化、脱羧反应等。本研究的成果对β-内酰胺类物质的高效去除降解技术的工艺研发提供重要参考。 综上，本论文选择了左氧氟沙星和阿莫西林两种典型抗生素，通过深入研究其在二氧化锰、高锰酸钾两种体系中的转化机制，旨在全面揭示不同种类的抗生素在人工环境过程（水处理典型工艺）和自然环境过程（土壤/沉积物体系）中的转化行为。结果发现两种氧化反应体系均其有比较显著的转化降解，主要机理涉及氧化、脱烷基、脱羧、开环等。氧化处理效果和与反应转化机制随反应体系氧化剂性质不同而有所差异。本研究不仅可以为不同种类抗生素在环境中的转化行为及其潜在环境风险评价提供基础数据，还可以为该类抗生素废水处理技术的选择和工艺参数的优化提供技术支持。 |
| 英文摘要 | A large volume of antibiotics and their derivatives have entered into environment in various ways due to their mass production and widespread use even abuse. It has been paid much attention on the potential harm to human health and ecological security due to the occurrence of drug resistant bacteria in the environment. In this paper, two typical antibiotics in tremendous usage and high detection concentration (levofloxacin and amoxicillin) were targeted to explore their transformation mechanisms and toxicity assessments in preoxidation process with potassium permanganate and catalytic oxidation with manganese oxides. The research results would not only provide useful information for scientifically evaluating the potential risk of this kind of antibiotics, but for developing effective degradation process for removing these antibiotics from wastewater or other environmental matrices. Main research work carried out in this paper is as follows: This paper chose birnessite (δ-MnO2), which is a natural component in soil/sediment media with strong oxidative activity and was synthesized according to the method by Murray and characterized, studying levofloxacin transformation mechanisms and toxicity assessments in δ-MnO2 treatment systems. The targeted material δ-MnO2 is a mineral oxide ubiquitously present in soils and sediments and the most abundant manganese oxides with high surface area, high oxidative capacity, high cation exchange capacity and low zero point of charge.. Experiments were conducted to explore different reaction time and δ-MnO2 dosage on the oxidative transformation. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, ten transformation products in the oxidation systems were separated and identified. The possible transformation pathways of levofloxacin in δ-MnO2 treatment system were proposed based on chemical reaction principles, including two types of reactions: oxidation and dealkylation. Meanwhile, to trace the changes in genotoxicity and antibacterial activity during the treatment process of LEV by δ-MnO2, the umu test and Escherichia coli growth test were conducted respectively. The results showed the genotoxicity of the reaction mixture significantly declined in response to treatment with δ-MnO2 and was well correlated with the residual LEV, implying that the original piperazine ring had the strongest genotoxicity effect. The antibacterial activity of the reaction mixtures significantly decreased at the initial loading of δ-MnO2, illustrating that the piperazine ring skeleton significantly contributed to the antibacterial activity of quinolone antibiotics. The results of this study would provide useful information for developing effective degradation process for removing these antibiotics from wastewater or other environmental matrices. Meanwhile, levofloxacin transformation behaviors in permanganate oxidation system were explored in this paper. LEV could be rapidly degraded, and high loading of permanganate and low pH conditions would promote the transformation of LEV. With the help of ultra high performance liquid phase chromatography tandom with quadupole time of flight mass spectrometer, nine main products were identified. The possible transformation pathways of LEV in permanganate system were proposed under differenet pH conditions, including oxidation, dealkylation, and so on. Especially, the variation of genotoxicity for reaction system was traced using SOS/umu assay. The results indicated that the genotoxicity decreased significantly during the oxidation process just like δ-MnO2 reaction system. The regression analysis showed that the residual LEV concentration was linearly correlated with the genotoxicity of reaction mixture, implying that the piperazine ring was responsible for genotoxicity. This study would provide a useful reference for developing effective degradation methods for quinolone antibiotics in wastewater. Moreover, amoxicillin transformation mechanisms in δ-MnO2 oxidation system were explored in this paper. Amoxicillin could be rapidly removed up to 80% at 100 dosage ratio in 6d. The possible transformation pathways of amoxicillin in δ-MnO2 oxidation system were proposed, including ring cleavage, oxidation, decarboxylation and so on. This study would provide a useful reference for developing effective degradation methods for β-lactam antibiotics. In conclusion, levofloxacin and amoxicillin were chosen as targets to explore their transformation mechanism with MnO2 and potassium permanganate, aiming to reveal transformation behaviors of typical antibiotics in artificial process (typical wastewater treatment process) and natural degradation process (soil-sediment system). Research results demonstrated that antibiotics could degrade significantly in the two oxidative systems, including oxidation, dealkylation, decarboxylation and ring cleavage. And degree of oxidation and molecular transformation mechanisms were different along with different characteristics of two systems. Research work in this paper will provide basic data and theoretical guidance for transformation behaviours of these antibiotics in environmental matrices and scientifically evaluating potential environmental risk. Moreover, the research outcomes will provide technical support for water treatment technology option and technological parameter optimization for these antibiotics in practice. |
| 公开日期 | 2015-07-07 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15709]  |
| 专题 | 生态环境研究中心_环境化学与生态毒理学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 李媛. 锰氧化物在去除典型抗生素药物中的应用研究[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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