Collaborative Research: Stable isotope investigation of Fe oxide reactivity and natural isotope fractionation

合作研究：氧化铁反应性的稳定同位素研究和天然同位素分馏

• 批准号: 1122855
• 负责人: Clark Johnson
• 金额: $ 25.99万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1122855&HistoricalAwards=false
• 关键词: Collaborative; Research; Stable; isotope; investigation

Iron is well known to change its oxidation state, where, for example, iron metal (Fe0) rapidly oxidizes to ?rust? in the form of Fe3+ oxides and hydroxides. The reverse may occur, where, for example, microbial processes may reduce Fe3+ oxide and hydroxide minerals to Fe2+ minerals or aqueous solutions. These changes, termed ?redox? transformations, profoundly affect the reactivity of iron oxide and hydroxide particles, which in turn may dramatically change the behavior of elements such as carbon, nitrogen, and phosphorus through changes in the absorption properties. Redox transformations affect the reactivity of iron oxide and hydroxide minerals, particularly in nanoparticles (defined as particles that have diameters in the nanometer range ? one-billionth of a meter). It is now recognized that nanoparticles are ubiquitous in the environment and represent one of the major means by which chemical reactions occur.The work supported by this collaborative grant will bring together researchers and students from geology and engineering, applying a unique isotopic approach to understanding the reactivity of nanoparticulate iron oxides and hydroxides. By studying the spectral properties and relative abundance of the different isotopes of Fe (54Fe, 56Fe, and 57Fe), this work will provide a fingerprint for changes in chemical reactivity of the minerals goethite and magnetite, two very common iron minerals in the environment. The work will study the impact of particle size and chemical composition on particle reactivity. These results will in turn have direct application to studies of paleoclimate, environmental remediation, agricultural practices, and water quality.

众所周知，铁会改变其氧化态，例如，铁金属 (Fe0) 会迅速氧化成锈？以 Fe3+ 氧化物和氢氧化物的形式存在。 相反的情况也可能发生，例如，微生物过程可能会将 Fe3+ 氧化物和氢氧化物矿物质还原为 Fe2+ 矿物质或水溶液。 这些变化被称为“氧化还原”。转变，深刻地影响氧化铁和氢氧化物颗粒的反应性，进而可能通过吸收特性的变化极大地改变碳、氮和磷等元素的行为。 氧化还原转化会影响氧化铁和氢氧化物矿物的反应性，特别是纳米颗粒（定义为直径在纳米范围内（十亿分之一米）的颗粒）。 现在人们认识到纳米粒子在环境中无处不在，是发生化学反应的主要方式之一。这项合作资助支持的工作将汇集地质学和工程学的研究人员和学生，应用独特的同位素方法来了解纳米粒子纳米颗粒铁氧化物和氢氧化物的反应性。 通过研究 Fe 不同同位素（54Fe、56Fe 和 57Fe）的光谱特性和相对丰度，这项工作将为针铁矿和磁铁矿（环境中两种非常常见的铁矿物）矿物的化学反应性变化提供指纹。 这项工作将研究颗粒尺寸和化学成分对颗粒反应性的影响。 这些结果将直接应用于古气候、环境修复、农业实践和水质的研究。