硫化纳米零价铁/生物炭对太湖梅梁湾重金属污染底泥的修复效应及行为作用机制

河湖底泥重金属污染对生态环境和人类健康造成了极大威胁，是亟待解决的问题。目前已发现改性纳米零价铁在底泥重金属修复方面具有较大的应用潜力，但其修复效应和作用机制尚不清楚。为此，本项目拟以太湖梅梁湾重金属污染底泥为研究对象，首先通过优化调控制备条件与应用过程得到适用于表层底泥修复的硫化纳米零价铁/生物炭（S-nZVI/BC）复合材料；然后探究修复底泥中重金属的迁移转化特性，并结合生物可利用性、微生物生化活性和植物毒性效应等生物效应分析，全面探讨S-nZVI/BC复合材料体系对重金属污染底泥的修复效应；最后考察修复过程中底泥理化性质变化，构建吸附模型，并重点剖析铁还原过程对重金属的固定化作用和机理，以期从非生物和生物过程综合揭示S-nZVI/BC复合材料修复重金属污染底泥的行为作用机制。项目有望为重金属污染湖泊底泥的修复提供理论依据与实践参考，有助于湖泊底泥生态环境的改善。

It is an urgent problem that the heavy metals contamination in river and lake sediments poses a huge threat to the ecological environment and human health. At present, it has been found that the modified nanoscale zero-valent iron has great potential in the remediation of heavy metals contaminated sediment, while its remediation effect and mechanism remain unclear. Therefore, the heavy metal contaminated sediment in Meiliang Bay of Taihu Lake is taken as the research object in this project. The sulfidated nanoscale zero-valent iron/biochar (S-nZVI/BC) composite material suitable for surface sediment remediation is obtained by optimizing the preparation conditions and application processes. Then, the migration and transformation characteristics of heavy metals in the remediation sediment are explored, and combined with the analyses of biological effects such as bioavailability, microbial biochemical activity and phytotoxicity, the remediation effect of S-nZVI/BC composite system on heavy metal contaminated sediment is comprehensively discussed. Finally, the changes of physicochemical properties of sediment in the remediation process are investigated, the adsorption model is constructed, and the immobilization effect and mechanism of heavy metals in the iron reduction process are particularly analyzed, so as to reveal the behavior and mechanism of S-nZVI/BC composite in the remediation of heavy metal contaminated sediment from both abiotic and biological processes. The project is expected to provide theoretical basis and practical reference for the remediation of heavy metal contaminated lake sediment, which contribute to the improvement of the ecological environment of lake sediment.