黑碳催化环境有机污染物降解的定量构-效关系和微观机理研究

Black carbon-mediated degradation is an important fate process of some organic contaminants in nature environment, as well as a critical part of the environmental remediation technology involving black carbon. Nevertheless, little is known about the mechanism of black carbon-mediated degradation; and there is a major knowledge gap in the methodology and models for predicting its catalytic activity. To address these scientific questions, the structure of black carbon will be manipulated by controlling the feedstock, pyrolysis conditions, as well as the postproduction surface modification. Complementary techniques will be employed to qualitatively and quantitatively characterize the bulk and surface structure of black carbon, forming a structure descriptor matrix. Batch reaction experiments will be carried out to measure the reaction kinetics of the black carbon-mediated degradation of nitro aromatic compounds and chlorinated aliphatic hydrocarbons, and the molar ratio of the reaction products. The reaction pathway and the major environmental controlling factors will be identified. Based on the structure descriptor matrix and the reaction kinetics, a quantitative structure-activity relationship will be constructed. Furthermore, complementary experiments including the electrical cell, multi-stage reduction, and inhibition experiments will be conducted to reveal the mechanism governing the black carbon-mediated degradation process. The outcome of this project will provide fundamental knowledge and novel technologies for better assessing the impact of black carbon on the environmental fate of organic contaminants and the development of remediation technologies involving black carbon applications.

黑碳催化的降解反应是部分有机污染物在自然环境中消减和解毒的重要途径，也是以黑碳为核心的环境修复技术中的重要过程。然而，目前黑碳催化有机污染物降解的微观机理尚不明确，并且缺乏预测其催化活性的模型和方法。项目拟通过精确地控制黑碳来源和生成条件，辅以后期的表面改性来调控黑碳结构；再通过相互补充的表征手段对黑碳及其界面结构进行定性定量表征，建立详细准确的表征因子库；解析黑碳催化硝基芳香类化合物和脂肪族卤代烃降解的反应产物和其摩尔比例，测定反应动力学参数，阐明降解路线和关键环境决定因素；继而进行黑碳结构特征和其催化活性之间的相关性分析，揭示其定量构-效关系；最后，结合化学电池、多级还原反应、醌结构位点抑制实验结果，揭示黑碳催化环境有机污染物降解的微观机理。该研究将为更加准确地评估黑碳对有机污染物环境归趋的影响以及指导黑碳环境修复技术提供科学依据和新技术方法。

溶解态黑碳是黑碳连续体中可溶解于水的组分，是淡水和海洋溶解性有机质的关键组分，在全球碳循环和有机污染物的环境归趋过程中起着重要作用。目前，对溶解态黑碳在全球碳循环和污染物环境效应中的作用还没有清晰的认识。本项目解析了溶解态黑碳的释放特征和分子结构特性，构建了表征因子库，与标准天然有机质进行了比较研究；揭示了溶解态黑碳胶体行为的主控作用力和环境因子，评估了光老化过程对其胶体行为的影响，探讨了溶解态黑碳在淡水和河口地区可能的分馏行为；揭示了溶解态黑碳的光化学活性，阐明其产生活性氧自由基的机制和活性位点，解析了活性氧自由基对其光转化过程的贡献；揭示了溶解态黑碳结构特性与光化学活性之间的定量构-效关系，建立了其光化学活性的定量预测模型，阐明了预测模型的理论依据。项目成果为科学评估溶解态黑碳在有机污染物环境归趋中的作用提供了关键信息和理论基础。