腐殖化过程中典型有机污染物转化机制的研究

发布时间：2018-05-06 11:15

本文选题：腐殖化 + 阿特拉津　；参考：《南京农业大学》2015年硕士论文

【摘要】：腐殖化是外源有机物在环境中转化的一个重要途径,它导致小分子物质聚合或与土壤有机质结合,最终形成无定型的土壤有机质。全面了解腐殖化过程中有机污染物转化的机理,可为科学评估腐殖化过程对有机污染物在环境中的转化和风险提供可靠依据。本研究选择阿特拉津(ATZ)作为研究对象,对ATZ与有机质结合的机理进行深入探究,分析产物。研究结果表明,在一系列结构不同的腐殖质模拟化合物中,苯胺明显促进ATZ的去除。由于ATZ中含有的C1原子具有强电负性,使得与之相连的碳原子很容易受到苯胺结构中亲核基团(-NH2)的攻击,因此这两种物质间可能通过亲核取代途径进行结合。本研究还选取环境中普遍存在的氨基酸/多肽等亲核物质对ATZ形成结合态残留的影响进行研究。实验结果表明,含巯基(-SH)的氨基酸/多肤可有效地去除ATZ,氨基酸/多肽中与ATZ反应的活性官能团是-SH。除含硫氨基酸/多肽外,硫醇和硫化钠也能够与ATZ反应。本研究选取卤代酚作为典型的酚类有机污染物,探究其在漆酶催化过程中的反应动力学,探讨了腐植酸(HA)、金属离子对卤代酚转化的影响,深入分析反应产物。实验结果表明,漆酶催化氧化卤代酚遵循二级反应动力学规律。HA存在时,抑制卤代酚的转化,反应遵循一级反应动力学规律;通过动力学模型分析HA的作用机理,结果表明HA充当卤代酚自由基的淬灭剂。1 mmol·L-1 Cu2+促进卤代酚的转化,随Cu2+浓度增加则会抑制卤代酚的转化。卤代酚自由基通过C-C或C-O共价键结合分别生成羟基卤代联苯和羟基卤代联苯醚等聚合产物。部分聚卤代产物具有内分泌干扰性,对生态系统和人类健康存在一定威胁。本研究为聚卤代芳香族化合物的来源提供了科学依据。此外,利用模型化合物(3,5-二羟基苯甲酸、间苯二酚)模拟腐殖质对卤代酚反应的影响。结果表明,3,5-二羟基苯甲酸一定程度上模拟了 HA的反应,间苯二酚可抑制卤代酚的转化,但随其投加量的增加,抑制效果没有显著变化。反应过程中有卤代酚与模型化合物通过C-C/C-O交叉聚合的产物和具有二VA英结构的物质生成。
[Abstract]:Humification is an important way for the transformation of exogenous organic matter in the environment, which leads to the aggregation of small molecular matter or the combination with soil organic matter, resulting in the formation of amorphous soil organic matter. An overall understanding of the mechanism of organic pollutant transformation during humification can provide a reliable basis for the scientific assessment of the transformation and risk of organic pollutants in the environment. In this study, atrazine (ATZ) was selected as the research object, and the mechanism of the combination of ATZ and organic matter was studied in depth, and the product was analyzed. The results showed that aniline promoted the removal of ATZ in a series of humus mimic compounds with different structures. Due to the strong electronegativity of C1 atoms in ATZ, the associated carbon atoms are vulnerable to attack by the nucleophilic group (-NH _ 2) in aniline structure, so the two substances may be bound by nucleophilic substitution. The effect of nucleophilic substances such as amino acid / polypeptide on the formation of binding residues of ATZ was also studied. The results showed that the amino acid / polypeptide containing sulfhydryl group could effectively remove ATZs, and the active functional group which reacted with ATZ in amino acid / polypeptide was -SHH. Mercaptan and sodium sulfide can react with ATZ in addition to amino acid / polypeptide containing sulfur. In this study, halogenated phenols were selected as typical phenolic organic pollutants, and their reaction kinetics in laccase catalysis was studied. The effects of humic acid and metal ions on the conversion of halogenated phenols were discussed, and the reaction products were analyzed in depth. The results showed that laccase catalyzed oxidation of halogenated phenol followed the second order reaction kinetics law. In the presence of HA, the transformation of halogenated phenol was inhibited, and the reaction followed the first order reaction kinetics law, and the mechanism of HA action was analyzed by kinetic model. The results show that HA acts as the quenching agent of halogenated phenol radical. 1 mmol L-1 Cu2 can promote the transformation of halogenated phenol. With the increase of Cu2 concentration, the transformation of halogenated phenol is inhibited. Hydroxyl halogenated biphenyls and hydroxy halogenated diphenyl ethers were synthesized from halogenated phenols by C-C or C-O covalent bonding respectively. Some polyhalogenated products are endocrine disrupting, which is a threat to ecosystem and human health. This study provides a scientific basis for the origin of polyhalogenated aromatic compounds. In addition, the effects of humus on the reaction of halogenated phenols were simulated by using the model compounds of 3 ~ (3) -dihydroxybenzoic acid and resorcinol. The results showed that the HA reaction was simulated to a certain extent, and resorcinol could inhibit the transformation of halogenated phenol, but with the increase of its dosage, the inhibitory effect did not change significantly. During the reaction, halogenated phenols and model compounds were synthesized by C-C/C-O cross-polymerization and diVA structure.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X132

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