化学稳定修复后土壤重金属再迁移行为及关键驱动机制研究

项目名称： 化学稳定修复后土壤重金属再迁移行为及关键驱动机制研究

项目编号： No.21507097

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 化学工业

项目作者： 梁媛

作者单位： 苏州科技大学

项目金额： 22万元

中文摘要： 化学稳定法是向土壤中添加稳定化材料改变土壤重金属形态，以降低重金属生物可利用性的一种污染土壤修复方法。但污染场地修复后土壤环境会发生改变，可能引起已固定重金属的再次活化。本课题以土壤-生物炭-重金属为研究体系，研究在灌溉、酸雨、冻融等条件下，生物炭修复后的Pb、Cd再迁移行为及关键驱动机制。在生物炭修复污染土壤中Pb、Cd的稳定化效果的基础上，通过解吸实验研究在界面化学驱动力（pH、离子强度、DOC）或物理驱动力（冻融）作用下，被生物炭修复后的重金属再迁移行为及关键驱动因子；并进一步通过动态淋溶实验，研究在界面化学和水力学交互作用下，重金属及生物炭的迁移分布特征，阐述重金属及生物炭协同迁移作用机制；进而利用Hydrus软件模拟重金属的迁移行为。最终揭示降雨灌溉条件下，生物炭修复后重金属的再迁移行为及驱动机制，更科学的评价生物炭对土壤重金属修复的长期稳定性。

中文关键词： 重金属；生物炭；活化；迁移转化；驱动机制

英文摘要： Chemical immobilization has been considered as a promising soil remediation technique, in which soluble heavy metals or organic contaminants are converted into stable forms by amendments, thus mobility and bioavailability of contaminants are reduced. The re-mobilization of initially stabilized contaminants is possible due to environmental changes under field conditions. This project will focus on the study of re-mobilization and its driving mechanism of the biochar-immobilized metals under rainfall，irrigation and freeze thawing. First of all, an incubation experiment will be conducted to determine how biochar induced immobilization of Pb and Cd. Second, a batch desorption experiment will be carried out to demonstrate the process and its key drive mechanisms of Pb and Cd remobilization in the biochar-amended soil in response to the changes of pH, ionic strength and freeze thawing. In addition, the column-based leaching experiment will be conducted to measure the downward migration of metals and biochar from biochar-treated soil under simulated rainfall and irrigation, which further reveal the synergistic effect between heavy metals and biochar. Finally，the transportation of heavy metals will be simulated by hydrus software.The study could highlight the assessment the long-term stability of biochar-amended heavy metals contaminated soil.

英文关键词： heavy metals;biochar;remobilization;transportation and transformation;driving mechanism