Development of tungsten stable isotope analysis for constraining sorption mechanisms and tracking the transport and fate of tungsten

开发钨稳定同位素分析，用于约束吸附机制并跟踪钨的运输和归宿

• 批准号: 1914186
• 负责人: Laura Wasylenki
• 金额: $ 19.73万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-20 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1914186&HistoricalAwards=false
• 关键词: Development; tungsten; stable; isotope; analysis

In this project funded by the Environmental Chemistry Program in the Chemistry Division at the National Science Foundation, Professor Laura Wasylenki of Indiana University (IU) develops a new way to assess how and to what extent sorption to mineral particles changes the mobility of toxic metals in contaminated settings. The new approach enables better prediction of the transport and fate for many metals, but the focus here is on tungsten (W), recently declared an "emerging contaminant of concern" by the US EPA. This approach takes advantage of variations in the stable isotope ratios of tungsten (e.g., W-183/W-182), which are highly sensitive to differences in the numbers, lengths, and strengths of chemical bonds involving the metal atoms. Stable isotope systematics are used to probe the molecular-scale interactions between dissolved W and porous media at realistic concentrations in the environment, but inaccessible to conventional spectroscopic techniques such as extended X-ray absorption fine structure (EXAFS) analysis. Concurrently, an innovative informational effort is launched at Indiana University to educate the campus community about where metals in everyday objects come from and what hazards and consequences are associated with taking those resources from the Earth. A series of signs are displayed on campus with quiz questions and QR (quadratic residue) code links that are developed by interns in IU's Office of Sustainability, with assistance from the Office of Science Outreach and Professor Wasylenki's research students.Simple sorption experiments and precise isotope analyses yield quantitative information about isotope fractionation during sorption of W onto four common sorbent phases. Studies are made first at high concentrations, where EXAFS provide information directly about coordination chemistry and sorption mechanisms, and then at field-relevant conditions, where isotopes may be the only way to constrain sorption mechanisms. Computational quantum mechanical modeling complement the experiments, isotope analyses, and EXAFS analyses. The modeling studies predict the expected isotope offsets between monomeric and polymeric species of W, which form in solution and as sorbed complexes. The work advances what is known about the environmental chemistry of tungsten and enables stable metal isotopes to be used as a tool for tracking transport and fate of metal contaminants.

在国家科学基金会化学部门的环境化学计划资助的该项目中，印第安纳大学（IU）的劳拉·瓦纳基（Laura Wasylenki）教授开发了一种新的方法来评估如何以及在何种程度上对矿物质颗粒的吸附方式改变了被污染的环境中有毒金属的流动性。这种新方法可以更好地预测许多金属的运输和命运，但是这里的重点是钨（W），最近宣布了美国EPA的“新兴污染物”。这种方法利用了钨的稳定同位素比（例如W-183/W-182）的变化，这些比率对涉及金属原子的化学键的数量，长度和强度高度敏感。稳定的同位素系统用于探测环境中溶解的W和多孔培养基之间的分子尺度相互作用，但对于传统的光谱技术（例如扩展的X射线吸收良好结构（EXAFS）分析），无法访问的环境中。同时，在印第安纳大学发起了一项创新的信息，以教育校园社区的日常物品中的金属来自何处以及与从地球中获取这些资源有关的危害和后果。 A series of signs are displayed on campus with quiz questions and QR (quadratic residue) code links that are developed by interns in IU's Office of Sustainability, with assistance from the Office of Science Outreach and Professor Wasylenki's research students.Simple sorption experiments and precise isotope analyses yield quantitative information about isotope fractionation during sorption of W onto four common sorbent phases. 首先在高浓度下进行研究，其中EXAF可以直接提供有关协调化学和吸附机制的信息，然后在与场相关的条件下进行，其中同位素可能是限制吸附机制的唯一方法。计算量子机械建模补充了实验，同位素分析和EXAFS分析。 建模研究预测了W溶液中形成的单体和聚合物物种之间的预期同位素偏移。这项工作推进了有关钨的环境化学的了解，并使稳定的金属同位素可以用作跟踪金属污染物的运输和命运的工具。