基于碳材料的农药多残留分析与水中污染物的脱氯降解研究

发布时间：2018-05-18 14:16

  本文选题：农药多残留分析 + 石墨烯　； 参考：《中国农业大学》2016年博士论文

【摘要】：常见的碳材料包括活性炭、石墨、石墨化炭黑、碳纤维、金刚石、富勒烯、碳纳米管和石墨烯。作为一种新颖的、环境友好的碳纳米材料,石墨烯具有优异的结构、热学、力学、电学和光学方面的性能,而石墨烯的应用极有可能掀起一场席卷全球的颠覆性新技术新产业革命。石墨烯的比表面积巨大,其蜂窝状的六元环结构能使六个碳原子形成离域大π键。这些特性使石墨烯对有机物的富集能力很强,因此,石墨烯在污染物痕量分析检测与吸附降解领域的应用备受关注。本论文制备了石墨烯粉末、石墨烯衍生物一氨基修饰石墨烯、以及类石墨烯结构的碳材料一石墨型氮化碳。针对农药残留分析样品前处理过程中待测物的浓度很低、基质背景干扰严重的问题,把石墨烯系列材料作为分散固相萃取剂,应用于多种样品的农药残留分析的样品前处理技术中。改良后的分析方法符合样品前处理技术向“省时、省力、价格低廉、减少有机溶剂、减少环境污染”方向发展的要求。主要研究结果包括：(1)制备了石墨烯,并采用拉曼光谱和X射线衍射手段进行表征。石墨烯与PSA、GCB的混合材料作为分散固相净化剂,用于韭菜、洋葱、大蒜的24种农药多残留分析。在研究过程中,优化了石墨烯的用量,证明了石墨烯的使用有助于净化背景干扰物,并验证了方法回收率、检出限、定量限、基质效应等,方法的平均回收率为70.1-109.7%,相对标准偏差低于15.6%。该方法也适用于市场样品的常规检测。(2)制备了三种不同链长的氨基官能团修饰的石墨烯,并对其进行傅里叶红外光谱、X射线光电子能谱、X射线衍射和扫描电子显微镜分析。甲胺修饰石墨烯作为分散固相净化剂,用于油菜籽、花生、大豆、芝麻中的31种农药多残留分析。实验证明了甲胺修饰石墨烯与PSA、MWCNTs等固相萃取剂相比,具有更加出色的背景干扰物净化能力。研究优化了甲胺修饰石墨烯的用量,验证了方法回收率、检出限、定量限、基质效应等,并对方法创新性进行了讨论。方法的平均回收率为70.5-100%,相对标准偏差≤13%。(3)制备了类石墨烯多孔结构的石墨型氮化碳,并进行透射电子显微镜、傅里叶红外光谱、X射线衍射和比表面积分析。建立了石墨型氮化碳作为分散固相吸附剂,用于果汁中的苯甲酰苯脲类农药的残留分析方法。研究优化了影响“萃取-解吸附”过程的多个影响因素,并通过“萃取-解吸附-再生”实验证明了石墨型氮化碳能被多次重复利用。研究验证了方法回收率、检出限、定量限、基质效应等,方法的平均回收率为70.4-96.4%,相对标准偏差≤13.9%,该方法适用于市场样品的常规检测。(4)测定了吸附平衡时间和溶液pH值对吸附效果的影响,利用Langmiur和Freundlich模型对吸附等温线进行拟合,并讨论了π-π相互作用和杂原子作用对吸附的影响。在斯德哥尔摩公约中,有机氯农药被列为持久性环境污染物,能在生物体内蓄积,对其后代产生致癌致畸形至突变作用。DDT是有机氯农药的代表,本论文选取了DDT的两个化学结构片段一三氯甲烷和氯苯,制备了活性炭负载的双金属催化体系,对三氯甲烷和氯苯进行脱氯降解研究。相对DDT而言,三氯甲烷和氯苯结构更为简单、产物单一,有利于深入探索催化剂的作用机理,为有机氯农药的降解提供研究基础。本论文制备了Pd/Fe-AC、Pd/AC、Pd/Fe三种催化剂,进行了比表面积测定、CO化学吸附测定Pd分散度以及ICP-MS技术测定Pd总量的表征,并用于水中有机污染物的吸附-脱氯降解。活性炭对三氯甲烷的吸附分配比是2800 L/kg,对氯苯的吸附分配比是35000 L/kg。以三氯甲烷和氯苯为催化降解对象,Pd的催化活性均是Pd/Fe-AC Pd/AC Pd/Fe, Pd/Fe-AC对三氯甲烷的催化脱氯率达94.3%,对氯苯的脱氯率为100%。对Pd/Fe-AC体系表现出优异催化性能的原因进行了探索,发现活性炭的吸附效应、Fe-和Pd间的电流作用、Fe0腐蚀产生的H2是促使Pd/Fe-AC快速高效降解三氯甲烷和氯苯的主要原因。Pd/Fe-AC对氯苯是完全脱氯,对三氯甲烷是不完全脱氯,因此,可以推测Pd/Fe-AC对DDT的脱氯降解亦为不完全脱氯反应,1,1,1-三氯甲基上的氯较难完全去除,但总的脱氯效率较高。
[Abstract]:Common carbon materials include activated charcoal, graphite, graphitized carbon black, carbon fiber, diamond, fullerene, carbon nanotube and graphene. As a novel, environmentally friendly carbon nanomaterial, graphene has excellent structural, thermal, mechanical, electrical and optical properties, and the application of graphene is likely to set off a sweeping sweep of the world. The subversive new technology and new industrial revolution. The specific surface area of graphene is huge, and its honeycomb six membered ring structure can make six carbon atoms form large off domain PI bonds. These properties make graphene rich in organic matter. Therefore, the application of graphene in the field of trace analysis and adsorption degradation of pollutants has attracted much attention. Graphene powder, graphene derivative monoamine modified graphene, and graphite like carbon material of graphene structure have been prepared. The graphene series material is used as a dispersible solid phase extractant in the process of pretreatment of pesticide residues. In the sample pretreatment technology of pesticide residue analysis, the improved analysis method accords with the requirements of sample pretreatment technology to "save time, labor, low price, reduce organic solvents and reduce environmental pollution". The main research results include: (1) the preparation of stonene and using Raman and X ray diffraction methods Characterization. The mixture of graphene and PSA, GCB as a dispersive solid phase purifier, used in the analysis of 24 kinds of pesticide residues in leek, onion and garlic. During the study, the amount of graphene was optimized. It was proved that the use of graphene could help to purify the background interferon, and verified the recovery rate, detection limit, quantitative limit, matrix effect and so on. The average recovery rate of the method is 70.1-109.7% and the relative standard deviation is lower than 15.6%.. The method is also suitable for the routine testing of the market samples. (2) three kinds of amino functional group modified graphene with different chain length are prepared, and their Fourier infrared spectroscopy, X ray photoelectron spectroscopy, X ray diffraction and scanning electron microscope analysis. Methylamine modification. As a dispersed solid phase purifier, graphene is used for the analysis of 31 kinds of pesticide residues in rapeseed, peanut, soybean and sesame. The experiment has proved that methylamine modified graphene has a better purifying ability of background interferon than PSA, MWCNTs and other solid phase extractants. The study optimized the amount of methylamine modified graphene and verified the recovery rate of the method. The detection limit, the quantitative limit, the matrix effect and the method innovation are discussed. The average recovery rate of the method is 70.5-100%, the graphite like carbon nitride of the porous structure of graphene like structure is prepared by the relative standard deviation less than 13%. (3), and the transmission electron microscope, the Fu Liyehong external spectrum, the X ray diffraction and the specific surface area analysis are carried out. Carbon nitride is used as a dispersible solid phase adsorbent for the analysis of benzylbenzourea pesticide residues in juice. Several factors affecting the "extraction desorption" process are studied and optimized. Through the "extraction desorption regeneration" experiment, it is proved that graphite type carbon nitride can be reused many times. Rate, detection limit, quantitative limit, matrix effect and so on, the average recovery rate of the method is 70.4-96.4%, the relative standard deviation is less than 13.9%. This method is suitable for the routine testing of the market samples. (4) the adsorption equilibrium time and the effect of the solution pH value on the adsorption effect are measured. The adsorption isotherms are fitted by Langmiur and Freundlich models, and the pion is discussed. In the Stockholm convention, organochlorine pesticides are listed as persistent environmental pollutants in the Stockholm convention. They can accumulate in organisms and produce carcinogenic deformities to their descendants to be the representative of organochlorine pesticides. In this paper, two chemical fragments of DDT were selected, and chloroform and trichloromethane were selected. Chlorobenzene, preparation of activated carbon loaded bimetallic catalytic system, dechlorination of chloroform and chlorobenzene dechlorination study. Relative to DDT, trichloromethane and chlorobenzene structure is more simple, the product is single, it is beneficial to explore the mechanism of the catalyst and provide the basis for the degradation of organochlorine pesticides. This paper has prepared Pd/Fe-AC, Pd/AC, Pd/Fe three catalysts were used to determine the specific surface area, CO chemisorption, Pd dispersion and ICP-MS technology for the determination of Pd total. It was used for adsorption dechlorination of organic pollutants in water. The adsorption distribution ratio of activated carbon to trichloromethane was 2800 L/kg, and the ratio of chlorobenzene to chlorobenzene was 35000 L/kg. with Trichloromethane and chlorobenzene as the ratio of chlorobenzene. The catalytic activity of Pd is Pd/Fe-AC Pd/AC Pd/Fe, the catalytic dechlorination rate of Pd/Fe-AC to trichloromethane is 94.3%. The reason that the dechlorination rate of chlorobenzene is 100%. to Pd/Fe-AC system has been explored. The adsorption effect of activated carbon, the action of the current between Fe- and Pd, H2 of Fe0 corrosion are promoted. The main reason for the rapid and efficient degradation of chlorobenzene and Chlorobenzene by Pd/Fe-AC.Pd/Fe-AC is completely dechlorinated and chloroform is not completely dechlorinated. Therefore, it is possible to speculate that the dechlorination degradation of DDT by Pd/Fe-AC is also incomplete dechlorination, and the chlorine on 1,1,1- three chloromethyl chloride is difficult to completely remove, but the total dechlorination efficiency is higher.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X592;S481.8
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本文编号：1906148