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Fenton法降解典型喹诺酮类抗生素的应用基础研究
Alternative TitleApplication of Fenton Degradation of Typical Quinolone Antibiotics
陈瑞骞
Subtype硕士
Thesis Advisor魏东斌
2014-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Discipline环境工程
KeywordFenton氧化 左氧氟沙星 洛美沙星 遗传毒性 抗菌活性 Fenton Oxidation Levofloxacin Lomefloxacin Genotoxicity Antibacterial Activity
Abstract    Fenton氧化是一种广受关注的高级氧化技术(AOPs),具有操作简便、成本低廉、环境友好等优点,在废水处理等环境领域极具发展潜力和应用前景。近年来采用Fenton氧化技术处理制药废水、农药废水、化工废水、垃圾渗滤液等的研究工作深入开展并取得了一系列的研究成果,为Fenton氧化技术实现产业化应用奠定了坚实的理论基础。
    最近几十年,抗生素的使用量不断增加,由此引发了诸如耐药微生物出现等环境问题,给生态系统和人类健康构成严重的威胁。因此寻找高效、低耗、绿色的抗生素降解技术成为摆在环保工作者面前的重要课题。本文以两种常用的喹诺酮类抗生素——洛美沙星(Lomefloxacin, LOM)和左氧氟沙星(Levofloxacin, LEV)作为模型污染物,采用Fenton高级氧化技术对这两种抗生素进行了降解实验,初步考察了降解效果和潜在环境风险。主要的研究内容和结果如下:
1. 以左氧氟沙星(LEV)作为模型污染物,采用Fenton试剂(H2O2/Fe2+)氧化降解水中LEV,通过正交试验初步筛选出适宜的反应条件并分别针对各影响因素开展研究。实验结果表明,选定的4个因素对Fenton试剂降解LEV的影响权重,从大到小依次为:Fe2+的初始浓度、反应时间、H2O2的初始浓度、初始pH值。采用优化后的反应条件:pH=6,H2O2和Fe2+初始浓度分别为0.75 mM和150 μM,处理初始浓度为50 μM的LEV溶液,反应60 sec后LEV的去除率达到96.5%,表明水溶液中LEV可被Fenton试剂有效去除。LEV的降解过程呈现出明显的―两段式‖(two-stage),反应初始阶段降解速度快(第一阶段),符合准一级反应动力学;反应中后期降解速度明显降低(第二阶段)。毒性试验结果表明,随着LEV的不断降解,体系的遗传毒性逐渐降低,表明此反应过程未生成具有高遗传毒性的中间产物或终产物,初步判断Fenton氧化处理LEV具有一定的可行性。
2. 以洛美沙星(LOM)作为模型污染物,采用Fenton氧化法对其进行降解,深入研究了以下4个因素:Fe2+初始浓度、H2O2初始浓度、初始pH值、LOM初始浓度对降解行为的影响。通过单因素实验并综合考虑成本效益筛选出最适宜的反应条件,即选取pH=6.5,Fe2+初始浓度、H2O2初始浓度分别为0.1 mM,0.5 mM,处理初始浓度为50 μM的LOM水溶液,反应5 min后LOM的去除率达到89%。表观动力学研究表明,在pH=6.5,LOM初始浓度为50 μM的条件下,采用初始速率法计算得到H2O2的反应级数为1.0925,Fe2+的反应级数为1.3054。umu试验结果显示在Fenton氧化降解LOM过程中,体系的遗传毒性在反应初期迅速降低,之后降低速度减缓,同时体系的抗菌活性也随着反应的进行逐渐降低,表明反应过程中未生成具有高毒性的副产物,且Fenton氧化可以去除抗生素的抗菌活性,降低了在环境中诱导产生耐药菌的风险。
Other Abstract     Fenton oxidation, one of the Advanced Oxidation Processes (AOPs), has gained much attention for its significant advantages in the wastewater treatment area. It is environmentally friendly, low-cost and high-efficient. In recent years, a lot of researches on the application of Fenton oxidation in treating pharmaceutical wastewater, pesticide wastewater, landfill leachate, etc. have been conducted. The results from these researches will establish a solid theoretical foundation for the pratical applications of Fenton oxidation technology. In recent decades, the increasing usage of antibiotics has triggered a series of environmental problems such as the induction of resistant microorganisms, which then pose a serious threat to the ecosystem and human health. Therefore it is very important to find efficient technologies for antibiotics degradation. In this paper, two widely used quinolone antibiotics, Lomefloxacin (LOM) and Levofloxacin (LEV) were chosen as model pollutants. Experiments on the degradation of these two antibiotics by Fenton oxidation were conducted, and the degradation characteristics and potential environmental risks were preliminary investigated. The main results are as follows:
Firstly, the degradation characteristics of LEV during the Fenton (H2O2-Fe2+) treatment were investigated. To obtain the best reaction conditions (reaction time, pH, the initial concentration of Fe2+ and H2O2), orthogonal tests and a series of experiments on the effects of each influencing factor were conducted. Operating at pH=6, [H2O2]0=0.75 mM, [Fe2+]0=150 μM, 96.5% of LEV was removed after 60-sec of treatment. The experimental results showed that Fenton treatment could effectively eliminate LEV from aquatic solution. A two-stage reaction was observed during the Fenton treatment on LEV, and LEV removal in the first stage conformed to pseudo-first-order reaction kinetics. The effects of initial concentrations of Fe2+ and H2O2 on the degradation kinetics were explored, respectively. The higher initial concentration of Fe2+ or H2O2 would increase the apparent rate constant kapp. The more important was that the genotoxicity of the reaction mixtures exhibited decreasing tendency during Fenton treatment process. This implied that Fenton process could effectively transform LEV to less genotoxic products.
Then the experiments of Lomefloxacin (LOM) degradation by Fenton oxidation process were conducted. The effects of four influencing factors, including initial pH values, the initial concentration of Fe2+, H2O2 and LOM, were studied and the best reaction conditions were finally obtained. Operating at pH=6.5, [H2O2]0=0.5 mM, [Fe2+]0=0.1 mM, 89% of LOM was removed after 5-min of treatment. The results of umu test showed that genotoxicity of the reaction system decreased during Fenton treatment. This implied that Fenton process could effectively degrade LOM to form less genotoxic products. At the same time, the antibacterial activity of the reaction mixtures exhibited decreasing tendency too, which might be attributed to the decomposition of the quinolone moiety of LOM after Fenton oxidation.
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/13484
Collection环境化学与生态毒理学国家重点实验室
Recommended Citation
GB/T 7714
陈瑞骞. Fenton法降解典型喹诺酮类抗生素的应用基础研究[D]. 北京. 中国科学院研究生院,2014.
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