粘土矿物调控土壤中二噁英的生成与机制

项目名称： 粘土矿物调控土壤中二噁英的生成与机制

项目编号： No.21277124

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 环境科学、安全科学

项目作者： 林坤德

作者单位： 浙江工业大学

项目金额： 80万元

中文摘要： 研究表明天然粘土矿物含有不明来因的高浓度二噁英，其同系物以OCDD为主，PCDFs相对较少，这种与已知人为源和自然源显然不同的二噁英同系物分布特征表明其可能另有来源。那么，是不是粘土矿物利用氯代污染物原位合成了二噁英？为回答这个问题，本项目将系统地研究粘土矿物强化氯代酚类化合物氧化合成二噁英的过程与机制。实验拟选择环境中广泛存在的氯代酚类化合物为模型化合物，研究这些化合物在粘土矿物（包括天物粘土、含铁矿物和含锰矿物等）作用下氧化合成二噁英的能力与效率，分析生成的二噁英产物，建立二噁英生成动力学模型，考察环境因素如粘土矿物中共存有机质（如腐殖酸）、其他溶解质（如Ca2+、Mg2+等）和pH值等对二噁英生成的调控作用，结合量子化学理论计算，剖析反应机理，同时探讨氯代酚类化合物化学结构（氯原子取代位置和数目不同）对其氧化合成二噁英的影响。本研究成果将为土壤和粘土中二噁英的污染源解析提供新的参考。

中文关键词： 二噁英；持久性有机污染物；氯代酚类化合物；粘土；金属氧化物

英文摘要： Previous studies have documented the ubiquitous high levels of dioxins in natural clays. Their PCDD/F congener profiles are characterized by the predominance of octachlorodibenzodioxin (OCDD) and low levels of PCDFs. Such a unique PCDD/F congener profile does not match any known anthropogengic or natural dioxin sources, suggesting a novel dioxin origin. On the basis of these observations, a scenario is proposed that clay minerals may in situ catalyze dioxins synthesis using chlorinated pollutants as precursors. However, knowledge on the formation of dioxin via the reaction of chlorinated compounds with clay minerals is poorly understood. The primary objective of this study is to obtain a mechanistic understanding on the formation of dioxins from the oxidation of chlorophenols (CPs) by clay minerals. Specifically, we intend to select some ubiquitous CPs as the representative chlorinated compounds and natural clays, iron oxides and manganese oxides as the model clays. This project aims to i) understand the efficacy of dioxin synthesis from the oxidation of CPs by clays, ii) gain insight into the kinetics of dioxin congener formation, iii) evaluate the effects of coexisting organic matters (e.g., humic acid), co-solutes (e.g., Ca2+ and Mg2+) and pH on the reaction, iv) propose routes and mechanism to the formation

英文关键词： dioxins；POPs；chlorophenols；clay；metal oxides