湖泊沉积物/水界面铁氧化物与锑的相互作用过程与机理研究

The environmental behavior and relevant microscopic mechanism of antimony (Sb) in sediment-water interface is an important part to recognize the environmental biogeochemical cycles and effects of Sb. According to few previous studies, the difference of environmental mobility between Sb and arsenic (As), as well as significant changes of Sb concentrations in water between the wet and dry season, suggested that redox conditions have an important influence on the release and migration of Sb. Iron oxide may play an important role during this process. The Taihu Lake and a typical lake near Hunan Sb smelting site will be chosen as study sites. This poject will focus on the following aspects: firstly, to study the distribution of different species of Sb in the vertical profile of sediment. Secondly, to study the effects of redox conditions on the release and migration of Sb. Thirdly, to understand the mechanism of interaction between iron oxide and Sb in sediment/water interface. In addition, to systematically explore the effects of other environmental factors including natural organic matter and microbes. The technique of diffusive gradients in thin films (DGT), X-ray absorption fine structure spectroscopy (XAFS), and high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry detection (HPLC-HG-AFS) will be used. Moreover, these research methods of trace element geochemistry, mineralogy, microbiology, spectroscopy and electrochemistry will also be applied in order to deeply study the interaction mechanism between iron oxide and Sb in sediment-water interface with a molecular level. This project will furtherly give a better understanding of the release and migration of Sb in sediment-water interface, and provide important scientific information for environmental control and management of Sb pollution in water environment.

锑在水体沉积物/水界面迁移转化行为和微观机制是认识其环境生物地球化学循环和效应的重要环节。前人的少量研究表明，锑砷的活性差异、以及不同季节湖泊水体中锑的显著变化受氧化还原条件的重要影响，铁氧化物可能在其中起重要作用。项目选择太湖及锑矿区典型污染湖泊为研究对象，研究湖泊沉积物/水界面不同形态锑的垂直剖面分布规律，探索不同季节氧化还原条件改变对锑释放迁移的影响，重点阐明沉积物/水界面铁氧化物与锑的相互作用机制，系统阐述氧化还原条件变化及有机质、微生物等环境要素对铁氧化物与锑相互作用的影响。运用DGT薄膜扩散梯度技术、XAFS精细结构技术及HPLC-HG-AFS分析技术，辅以微量元素地球化学、矿物学、微生物学、光谱学及电化学等研究手段，从分子水平上深入研究沉积物/水界面锑与铁氧化物的相互作用机理，研究将进一步深化认识锑在沉积物/水界面的释放迁移规律，为锑的环境污染控制与管理提供科学依据。

项目研究按任务书要求推进，重点研究了实验室条件下聚合硫酸铁对水体中高浓度锑的去除机理，甘肃陇星锑矿尾砂泄漏污染区、湖南锡矿山锑污染区沉积物/水界面锑形态的迁移转化行为和生态风险、以及铁氧化物在其中发挥的影响与作用机制。.项目研究取得了预期的研究成果，发表了标注资助的SCI论文6篇，申请国家发明专利5项（获授权2项），授权香港专利1项，申请公开PCT国际专利1项；依托本项目培养了1名博士及1名硕士研究生；研发的流域沉积物中重金属生态风险评估技术，在国家流域锑污染事故的风险评估中得到应用；部分研究成果获2016年度环保科技奖一等奖。.主要研究进展有如下三点：（1）进一步阐明了典型锑污染区水体和沉积物中锑的迁移转化规律及铁氧化物的影响，加深了对实际水环境中尤其是沉积物水界面锑的迁移释放的理解，有助于针对性的提出锑的污染控制措施。（2）揭示了关键环境因素对铁盐絮凝法去除水体中锑的影响并进一步阐明了絮凝法去除水体中锑的去除机理，为锑的突发事故应急处置提供技术支撑，为我国锑污染防控提供科学依据。（3）获取了磁性铁纳米材料吸附地表水中锑的优化参数并进一步阐明其吸附机理，为水体锑污染的防控提供了技术支撑，为探究锑的去除技术提供了新的思路。