纳米材料与重金属的共迁移机理及土壤胶体的协同机制

Research on the co-transport of nanoparticles and heavy metals, and the roles of soil colloids on colloid-facilitated nanoparticles or nanoparticles-heavy metals transport is significantly important for the environmental behavior of nanoparticles and heavy metals in soil. However, the knowledge on the mechanism and influence of co-transport is still limited. This project uses three different engineered nanoparticles (nanoscale zero-valent iron, nano-hydroxyapatite, and multi-walled carbon nanotubes) and several different contaminated soils from lead and zinc mine tailing. Based on the batch and column experiments by experimental and numerical analysis, the co-transport of nanoparticles and heavy metals in soils under variable physico-chemical conditions will be performed to deeply understand the mechanism, and the roles of the limited adsorption sites from nanoparticles competed by different heavy metals will be investigated. The roles of soil colloids under variable physico-chemical conditions (i.e. ionic strength, flow state) on colloid-facilitated transport of nanoparticles in soil will be investigated. The project will investigate the interactions between nanoparticles and soil colloids based on the experiments of soil fractionation and soil incubation, respectively. After that, the roles of soil colloids on the detachment and remobilization of heavy metal in soils in the presence of nanoparticles will be performed. This study will provide the scientific and theoretical knowledge on environmental protection of heavy metals in soils and application and potential risk of nanoparticles for soil remediation.

纳米材料与重金属的协同迁移，以及土壤胶体对单一纳米材料和纳米材料与重金属共存的两种体系下的协同迁移机理研究，对于理解重金属和纳米材料在土壤中的行为方式具有重要意义。目前关于这两方面的研究仍然缺乏。本项目选用三种人工合成纳米材料（纳米零价铁、纳米羟基磷灰石及多壁碳纳米管）和不同污染程度的铅锌尾矿土，以吸附和迁移实验为基础，通过实验和模拟深入理解纳米材料与重金属的协同迁移及影响机制，以及多种重金属对纳米材料竞争吸附位点机理；通过改变理化条件下(离子强度、流态等)阐明土壤胶体对纳米材料解吸附及再迁移的影响机制，并通过土壤分级和培养实验深入探讨土壤胶体与纳米材料的结合机理；以此为基础开展土壤胶体对纳米材料和重金属共存体系的解吸附和再迁移的影响机制研究。本研究可为重金属的污染防治及纳米材料应用于土壤修复及潜在风险提供科学依据及理论支持。

纳米材料与重金属的协同迁移，以及土壤胶体对单一纳米材料和纳米材料与重金属共存的两种体系下的协同迁移机理研究，对于理解重金属和纳米材料在土壤中的行为方式具有重要意义。目前关于这两方面的研究仍然缺乏。本项目选用两种人工合成纳米材料（多壁碳纳米管和生物炭）和不同污染程度的铅锌尾矿土，以吸附和迁移实验为基础，通过实验和模拟深入理解纳米材料与重金属的协同迁移及影响机制，以及多种重金属对纳米材料竞争吸附位点机理；通过改变理化条件下(离子强度、打断等)阐明土壤胶体对纳米材料解吸附及再迁移的影响机制，并通过土壤分级和培养实验深入探讨土壤胶体与纳米材料的结合机理；以此为基础开展土壤胶体对纳米材料和重金属共存体系的解吸附和再迁移的影响机制研究。结果表明，不同来源生物炭对重金属吸附、竞争吸附、竞争截留及共迁移存在差异；不同的表面活性剂(十二烷基苯磺酸钠，SDBS和曲拉通-100，TX100)对多壁碳纳米管的淋溶机制也有所不同，并且随着打断时间的增加，土壤胶体会更加显著的促进碳纳米管的释放与再迁移；不同重金属污染土壤对于重金属的赋存及结合与土壤的理化性质相关，其重金属的释放与再迁移也与土壤的理化性质具有一致的相关性。本研究可为重金属的污染防治及纳米材料应用于土壤修复及潜在风险提供科学依据及理论支持。