Fe(II)-Fe(III) Electron Transfer at Fe-containing Clay Minerals and its Effect on Hg(II) and Cr(VI) Transformation

含铁粘土矿物中 Fe(II)-Fe(III) 电子转移及其对 Hg(II) 和 Cr(VI) 转化的影响

• 批准号: 202271526
• 负责人: Dr. Anke Neumann
• 金额: --
• 依托单位: Department of Civil and Environmental Engineering
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/202271526?language=en
• 关键词: Fe; II; III; Electron; Transfer

The Fe(II)/Fe(III) redox couple plays an important role in biogeochemical cycles and for the dynamics of contaminant transformation in soils and aquifers. Despite the abundance of clay minerals in subsurface environments, redox processes of structural Fe in clay minerals as well as their impact on the mobility and toxicity of inorganic contaminants are not well understood. To address this knowledge gap, the proposed research aims to determine whether electron transfer between aqueous Fe(II), a reductant abundant in natural anaerobic environments, and structural Fe(III) in clay minerals occurs and how this reaction influences the transformation of the inorganic contaminants Hg(II) and Cr(VI). Isotope selective 57Fe-Mössbauer spectroscopy and infrared spectroscopy will be used to monitor the oxidation state and the structural environment of Fe in clay minerals and the Fe(III) product will be characterized with microscopic and spectroscopic methods. To gain a better understanding of inorganic contaminant reduction by clay mineral bound Fe(II), Hg(II) and Cr(VI) were chosen as exemplary contaminants, exhibiting complementary properties with regard to accessing the different surfaces of clay minerals. The application of stable isotope fractionation measurement to the non-traditional elements Hg and Cr will generate new insights into processes at the clay mineral-contaminant interface and will add to the further development of these novel isotope systems as source and process tracer. The findings will add to understanding the role of clay mineral bound Fe as a renewable source of redox equivalents in the environment and will improve the ability to assess the fate of contaminants, both inorganic and organic.

FE（II）/Fe（III）氧化还原夫妇在生物地球化学周期和土壤和含水层中污染物转化的动力学中起着重要作用。尽管在地下环境中粘土矿物质是抽象的，但粘土矿物质中结构性FE的氧化还原过程及其对无机污染物的迁移率和毒性的影响尚不清楚。为了解决这一知识差距，提出的研究旨在确定水（II）之间的电子传递，自然厌氧环境中丰富的含量减少以及粘土矿物质中的结构性Fe（III）是否发生以及这种反应如何影响无机污染物Hg（II）和CR（ii）的无机污染物的转化。同位素选择性57FE-Mössbauer光谱法和红外光谱法将用于监测粘土矿物质中Fe的氧化状态和Fe的结构环境，而Fe（III）产物将使用显微镜和光谱方法来表征。为了更好地理解粘土矿物结合（II），Hg（ii）和Cr（VI）的无机污染物的降低，选择作为典型污染物，在访问粘土矿物的不同表面方面具有完整的特性。将稳定的同位素分馏测量应用于非传统元素HG和CR将在粘土矿物 - 抗激素界面上产生新的见解，并将增加这些新型同位素系统作为源和过程词器的进一步开发。这些发现将增加理解粘土矿物结合的Fe作为环境中氧化还原当量的可再生能源的作用，并将提高评估无机和有机物污染物脂肪的能力。