华南金属矿区还原界面下天然金属纳米颗粒的形成及迁移机制

The formation of natural-occurring metal nanoparticles (MNPs) can be promoted under reduction interface in mining areas. The speciation and environmental behavior of heavy metals are therefore changed due to MNPs formation. However, studies on the speciation and formation mechanism of MNPs are still limited. Research on the aggregation and transport behavior of MNPs is not yet reported. This proposal is therefore to be performed for investigating the speciation and transport behavior of MNPs by using flooded mining tailings, artificial wetland, and contaminated paddy soil from typical mines in South China. Field investigations will be performed for the speciation analysis. Microcosm soil incubation experiments associated microbiome methods will be conducted for better understanding the dominated mechanism of MNPs formation. The transport behavior of MNPs in porous media will be investigated by using both saturated column experiments and numerical simulation. The transport behavior and the roles of the speciation and formation on the transport process in situ formation of MNPs will be deeply investigated by building microcosm-saturated column experiments. The results could help us for deeply understanding the formation and transport mechanisms of MNPs, filling in the knowledge of biogeochemical behavior of heavy metals at nanoscale cognitive in mining areas, and providing scientific support for pollution control and remediation of heavy metals.

矿区还原界面下可促进重金属形成天然金属纳米颗粒（MNPs），从而改变重金属的赋存形态与环境行为。然而，关于MNPs的形成机制及重金属形态变化却鲜少研究，MNPs形成后的稳定性及迁移行为更是未见报道。本课题拟选取华南地区典型金属矿区还原界面下淹水尾矿、人工湿地和污染稻田作为研究对象，通过野外调查掌握MNPs的赋存形态；结合微宇宙土壤培养实验及微生物组学等方法阐明MNPs形成的关键过程和机制；通过饱和土柱迁移实验和数值模拟相结合的方法，探讨MNPs在多孔介质中的迁移行为；并探索性构建微宇宙-土柱联合实验分析MNPs在原位形成后的迁移行为及与其赋存形态和形成机制的相关性。研究结果有助于深入理解MNPs形成及迁移机制，完善金属矿区重金属生物地球化学行为在纳米尺度上认知的空缺，为重金属污染防治与修复提供科学支撑。

矿区还原界面下可促进重金属形成天然金属纳米颗粒（MNPs），从而改变重金属的赋存形态与环境行为。然而，关于MNPs的形成机制及重金属形态变化却鲜少研究，MNPs形成后的稳定性及迁移行为更是未见报道。本课题拟选取华南地区典型金属矿区，通过野外调查掌握MNPs的赋存形态；结合微宇宙土壤培养实验及微生物组学等方法阐明MNPs形成的关键过程和机制；通过饱和土柱迁移实验和数值模拟相结合的方法，探讨MNPs在多孔介质中的迁移行为。总体结论如下：.（1）系统梳理了重金属矿区周边农田的土壤纳米颗粒组成及粒径特征，同时发现重金属在土壤纳米颗粒上的分配具有区域性及选择性的特征；.（2）明确了有机质浓度差异对硫酸盐还原菌活性及其介导铜纳米颗粒形成能力的影响；.（3）明确了pH、硫酸盐浓度、铜离子浓度等环境因素对土壤纳米颗粒稳定性的影响机制，发现土壤的理化性质导致了不同重金属释放与再迁移的主要方式及途径。. 研究结果有助于深入理解MNPs形成及迁移机制，完善金属矿区重金属生物地球化学行为在纳米尺度上认知的空缺，为重金属污染防治与修复提供科学支撑。