碳基材料的三维模型构建及其与有机污染物相互作用的描述

Understanding the interactions between organic pollutants and carbon-based particles is essential to predict the environmental behavior and potential health risk of organic contaminants in the environment. The theoretical calculations provide a powerful tool to reveal their interaction mechanisms. However, the traditional modeling concepts did not consider the three-dimensional structures of the carbon-based materials, which restricts the in-depth understanding of the sorption/desorption hysteresis and sequestration of organic pollutants. Therefore, this project intends to construct three-dimensional structures for several typical carbon-based materials (activated carbon, biochar, carbon black and humus). Based on the all-atom models or all-atomized micelle clusters, these three-dimensional structures will be constructed through changing the pore size, building the hollow pathway and modifying the interface after functional group manipulations and dynamic relaxation. Based on the constructed model, the interaction mechanism between these carbon-based materials and organic pollutants will be studied by simulating systematically, the thermodynamic and kinetic parameters, adsorption energy, and electronic transfer direction will be acquired. At the same time, the experimental parameters related to adsorption capacity, kinetics, and diffusion rate will be obtained through the specially-designed adsorption studies. The model-calculation and experimental results will be combined to identify and quantify the contribution of the individual adsorption mechanisms. This proposed research will break through the limitation of the traditional two-dimensional modeling concept. The proposed three-dimensional structural models will greatly benefit the research on the mechanism of adsorption and retaining organic contaminants by carbon-based materials. The outcome of this research can shed light on the mechanism of nonideal behavior of organic contaminants and thus guide the development of techniques for the effective control of organic pollution, for the eventual goal of ensuring human health and ecological safety.

有机污染物与碳基颗粒间的相互作用是影响其行为和风险的关键因素，理论计算的引入虽然为相关领域的研究提供了强有力的工具，但是传统理论计算缺少对碳基材料三维结构的描述，制约了对有机污染物解吸滞后、锁定/残留的深入理解。本项目拟以几类典型碳基材料（活性炭、生物炭、炭黑和腐殖质）为模型物质，在构建全原子模型或者全原子胶束团簇的基础上，挖空构建孔道、官能团修饰和动力学弛豫，构建碳基材料三维结构，系统模拟这些碳基材料与有机污染物之间的相互作用热力学和动力学参数，以及能量和电子转移等信息；在靶向性的吸附实验中，获取吸附容量、动力学和扩散速率、解吸滞后等参数，结合模型计算结果，识别并定量有机污染物吸附中各作用机制的贡献。本研究突破传统的平面微区吸附研究，立足于三维结构，从宏观和微观角度解析碳基材料吸附固定有机污染物的机制。项目研究成果可指导高效有机物污染治理策略的形成，进而保障人体健康和生态安全。

有机污染物与碳基颗粒间的相互作用是影响其行为和风险的关键因素，理论计算的引入虽然为相关领域的研究提供了强有力的工具，但是传统理论计算缺少对碳基材料三维结构的描述，制约了对有机污染物解吸滞后、锁定/残留的深入理解。本项目以几类典型碳基材料（活性炭、生物炭、炭黑和腐殖质）为模型物质，在构建全原子模型或者全原子胶束团簇的基础上，挖空构建孔道、官能团修饰和动力学弛豫，构建碳基材料三维结构，系统模拟这些碳基材料与有机污染物之间的相互作用热力学和动力学参数，以及能量和电子转移等信息；在靶向性的吸附实验中，获取吸附容量、动力学和扩散速率、解吸滞后等参数，结合模型计算结果，识别并定量有机污染物吸附中各作用机制的贡献。结果发现：（1）碳基材料二维结构特性和有机污染物的电子云密度和构型在吸附中起着关键作用，竞争吸附中竞争强度取决于吸附能和吸附位点的重叠；（2）碳基材料的自相互作用及孔隙都是影响吸附能力的重要因素，土壤NOM三维聚集体的形成及解体决定了对有机污染物的包裹和释放；（3）碳基材料的结构性质（氧化还原电势、持久性自由基、过渡金属及官能团种类）主导了对有机污染物的吸附和降解。本研究突破传统的平面微区吸附研究，立足于三维结构，从宏观和微观角度解析碳基材料吸附固定有机污染物的机制。项目研究成果可指导高效有机物污染治理策略的形成，进而保障人体健康和生态安全。