典型有机杀菌药物在环境中由OH引发的降解机理及动力学研究

发布时间：2018-01-15 01:19

本文关键词：典型有机杀菌药物在环境中由OH引发的降解机理及动力学研究　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：有机化学药物在当今人类的生产和生活中用量巨大,这些化学药物起到了抗菌杀菌的作用,对人类和农作物的健康具有重要意义,但同时也大量排放到环境当中,在大气、水、土壤中不断被检测到。这类物质在环境中能够进一步迁移、转化和富集,危害生态安全和人类健康。目前环境中的药物污染表现出了难降解,在环境中存在形式多样,以及降解环境复杂的特点。个人护理用品(PPCPs)和具有POPs性质的农药作为新型有机污染药物被广泛关注。本文选取个人护理用品添加剂三氯生、抗生素药物左氧氟沙星、和有机氯农药林丹作为研究对象。选取具有强氧化性的OH自由基作为引发剂,重点研究它们在OH自由基存在条件下的降解机理,为环境降解和废弃物处理提供了计算依据。全文采用了量子化学高精度密度泛函的方法(Density Functional Theory, DFT),在MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p)水平下重点计算了这三种物质由OH引发的降解路径,给出了热力学数据和动力学常数,得到一些重要结论：1.三氯生在气相条件下的OH降解机理和动力学研究。作为一种广谱杀菌剂,三氯生被大量用于生产和生活中,排放到环境中可对环境产生危害和污染。为了研究其在环境中的降解转化过程,量子化学计算的方法被用来计算其反应过程,并使用变分过渡态理论计算了其动力学数据。计算了OH引发的加成和抽提两条反应路径,并且研究了其进一步分解成酚类、醛类和其他易降解物质的反应。研究了三氯生在环境中转化成为二VA英、呋喃、和多氯联苯的降解机理和反应路径,表明三氯生在环境中可以转化成为毒性更大的持久性有机污染物,给环境带来潜在污染。在298.15 K时,加成反应和抽提反应的反应比例分别是kadd/ktotal=0.955和kabs/ktotal=0.045。说明加成反应是三氯生由OH引发的降解的主要反应,同时三氯生的抽提反应可在环境中进一步反应,转化成为二VA英。2.林丹在大气中的光催化反应机理研究研究了OH自由基引发的林丹在大气中光降解反应的机理。使用密度泛函(DFT)理论计算提出了林丹在大气中的链式反应机理。给出了每一降解步骤的势垒和反应热数据。同时用量子化学计算方法证明林丹脱C1无法直接从链式结构直接脱去HCl得到,给出了合理的脱C脱Cl机理,明确了林丹在大气中降解矿化的路径。3.左氧氟沙星在水中由OH引发的降解反应机理研究高级氧化方法可应用于左氧氟沙星的降解。利用OH自由基的高氧化活性可有效的去除水中的抗生素。研究OH自由基降解左氧氟沙星有助于给高级氧化处理技术提供更详尽的理论数据支持。文章分别研究了OH自由基对左氧氟沙星的加成和抽提降解。计算了反应热和反应势垒,找出能量最优降解路径并给出了动力学数据。
[Abstract]:The use of organic chemicals in the production and life of human beings is huge. These chemicals play an antibacterial role in bactericidal activities and play an important role in the health of human beings and crops. But at the same time, it is also released into the environment, which is continuously detected in the atmosphere, water and soil. These substances can be further transported, transformed and enriched in the environment. It is harmful to ecological security and human health. At present, drug pollution in the environment is difficult to degrade, and there are various forms in the environment. Personal care products (PPPs) and pesticides with POPs properties as novel organic pollutants have been widely concerned. In this paper, personal care products additive triclosan was selected. The antibiotic levofloxacin and organochlorine pesticide Lin Dan were selected as initiators to study their degradation mechanism in the presence of OH radical. It provides the basis for environmental degradation and waste disposal. The method of quantum chemical high precision density functional is used in this paper, which is called Density Functional Theory. DFT, in the MPWB1K/6-311, 3dffl / / MPWB1K / 6-31Gd / / MPWB1K / / MPWB1K / 6-31Gd. The degradation paths initiated by OH were calculated and the thermodynamic data and kinetic constants were given. Some important conclusions were drawn: 1.The degradation mechanism and kinetics of triclosan in gaseous phase. As a broad-spectrum bactericide, triclosan is widely used in production and life. In order to study the degradation and transformation process in the environment, quantum chemical calculation method is used to calculate the reaction process. The kinetic data were calculated by using the variational transition state theory, the addition and extraction pathways initiated by OH were calculated, and the further decomposition to phenols was studied. Reaction of aldehydes with other biodegradable substances. The degradation mechanism and reaction pathway of trichlorobenzene into diVA furan and polychlorinated biphenyls in the environment were studied. It shows that trichlorogenic can be converted into more toxic persistent organic pollutants in the environment and bring potential pollution to the environment. At 298.15 K. The ratio of addition reaction to extraction reaction is kadd/ktotal=0.955 and Kabs / ktotal0.045, respectively. It shows that the addition reaction is induced by OH. The main reaction to the solution. At the same time, the extraction reaction of triclosan can be further reacted in the environment. Studies on the photocatalytic reaction mechanism of Lin Dan in the atmosphere; the photodegradation mechanism of Lin Dan initiated by OH radical in the atmosphere. The mechanism of Lin Dan's chain reaction in the atmosphere is proposed by theoretical calculation. The potential barrier and reaction heat data of each degradation step are given. It is proved by quantum chemical calculation that Lin Dan can't remove C1 directly from chain structure. To HCl. A reasonable mechanism of dechlorination is given. The path of degradation and mineralization of lindane in the atmosphere .3.The degradation mechanism of levofloxacin in water induced by OH; the advanced oxidation method can be applied to the degradation of levofloxacin. The study on the degradation of levofloxacin by OH free radical is helpful to provide more detailed theoretical data for advanced oxidation treatment technology. This paper studies the effect of OH free radical on levofloxacin in water. Addition and extraction degradation of Fluorfloxacin. Reaction heat and reaction barrier were calculated. The optimal energy degradation path is found and the kinetic data are given.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X50

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