生物碳吸附西维因和土霉素的作用机制及构效关系

发布时间：2018-05-21 09:29

本文选题：生物碳 + 西维因　；参考：《浙江大学》2017年硕士论文

【摘要】：农药和抗生素的大量使用使得二者广泛共存在农田土壤中并引发多方面的生态危害,降低土壤中共存农药和抗生素的环境风险成为相关科研工作者的研究热点。吸附固定法是调控有机污染物环境行为和归趋的重要方法,生物碳由于其对各类污染物的优良吸附性能,在增强土壤吸附固定污染物方面具有良好的应用前景。本论文在评述土壤中共存农药和抗生素的暴露水平和生态风险,以及生物碳增强土壤吸附有机污染物的研究进展等基础上,以西维因(CBL)和土霉素(OTC)为代表,研究了生物碳对单一和混合体系下CBL和OTC的吸附机理和构效关系,并考察了生物碳对土壤吸附CBL和OTC的影响,重点探讨了去矿物处理对生物碳吸附CBL和OTC的影响及作用机制,试图为探讨生物碳增强土壤中共存CBL和OTC提供理论依据。论文取得了以下有价值的研究成果:(1)探明了生物碳吸附CBL和OTC的作用机制和构效关系。小麦秸秆生物碳和牛粪生物碳对CBL和OTC的吸附性能随其芳香性的增强而增强,但随生物碳极性的增强而降低,二者在生物碳上的吸附主要以专性点位吸附机制为主导。共存CBL和OTC在生物碳上呈现显著的竞争吸附现象,且竞争作用在高温生物碳上更显著,由于OTC优先于CBL占据生物碳表面的高能吸附位点,因而对CBL的吸附产生更强的竞争作用。(2)探明了去矿物处理对生物碳吸附CBL和OTC的影响及作用机制。去矿物处理使得牛粪生物碳整体的芳香性降低而极性增强,同时极大地增大了生物碳的比表面积,丰富了生物碳的孔隙结构。去矿物处理显著提高了生物碳对土霉素的吸附性能,而对西维因的吸附性能有微弱的降低。将去矿化生物碳对CBL和OTC的等温吸附曲线进行有机碳标化拟合分析,发现矿质组分对CBL在牛粪生物碳上的吸附起主要贡献作用,而对OTC的吸附产生微弱的抑制作用,这种差异归因于CBL在去矿化生物碳上的吸附以专性点位吸附为主,而OTC的吸附主要为孔填充机理。去矿化处理削弱了 OTC对CBL的竞争吸附强度,但增强了 CBL对OTC的竞争吸附作用。
[Abstract]:The extensive use of pesticides and antibiotics makes them co-exist in farmland soil and cause ecological hazards in many aspects. Reducing the environmental risk of co-existing pesticides and antibiotics in soil has become the research hotspot of related researchers. Adsorption and fixation is an important method to regulate the environmental behavior and fate of organic pollutants. Because of its excellent adsorption performance to various pollutants, biological carbon has a good application prospect in enhancing the adsorption of fixed pollutants in soil. On the basis of reviewing the exposure level and ecological risk of co-existing pesticides and antibiotics in soil, and the research progress of biocarbon enhanced soil adsorption of organic pollutants, this paper is represented by CBL and OTC- (Oxytetracycline). The adsorption mechanism and structure-activity relationship of CBL and OTC in a single and mixed system were studied. The effects of biochar on the adsorption of CBL and OTC in soil were investigated, and the effects of mineral removal on the adsorption of CBL and OTC were discussed. This paper attempts to provide a theoretical basis for exploring the coexistence of CBL and OTC in soil enhanced by biological carbon. The mechanism and structure-activity relationship of CBL and OTC were investigated. The adsorption of CBL and OTC on wheat straw and cow manure increased with the increase of aromaticity, but decreased with the increase of biological carbon polarity. Coexisting CBL and OTC showed significant competitive adsorption on biological carbon, and the competition was more obvious on high temperature biological carbon, because OTC had priority over CBL to occupy the high energy adsorption sites on the surface of biological carbon. Therefore, the adsorption of CBL has a stronger competitive effect on the adsorption of CBL and OTC by the removal of minerals and its mechanism. The removal of minerals can decrease the total aromaticity and increase the polarity of cow dung biological carbon, at the same time, it greatly increases the specific surface area of biological carbon and enriches the pore structure of biological carbon. The adsorption of oxytetracycline on biological carbon was significantly improved by mineral removal treatment, but the adsorption performance of carbaryl was slightly decreased. The isothermal adsorption curves of demineralized biological carbon for CBL and OTC were analyzed by organic carbon standard fitting analysis. It was found that the mineral components played a major role in the adsorption of CBL on the biological carbon of cow manure, but the adsorption of OTC was inhibited slightly. The difference is attributed to the fact that the adsorption of CBL on demineralized biological carbon is mainly specific point adsorption, while the adsorption of OTC is mainly pore filling mechanism. The demineralization treatment weakened the competitive adsorption intensity of CBL by OTC, but enhanced the competitive adsorption of OTC by CBL.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X592;X53

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