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Electron Transfer Mediators at Environmental Interfaces

环境界面处的电子转移介体

基本信息

批准号：
1506744
负责人：
Paul Tratnyek
金额：
$ 39万
依托单位：
Oregon Health & Science University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2018-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506744&HistoricalAwards=false
关键词：
Electron Transfer Mediators Environmental Interfaces

项目摘要

With this award, the Environmental Chemical Sciences Program in the Division of Chemistry is funding Professor Paul G. Tratnyek of the Oregon Health & Science University to investigate fundamental and applied aspects of how substances termed "electron shuttles" mediate redox reactions at solid-solution surfaces in the environment. Redox (oxidation-reduction) reactions are integral to many of the most important aspects of environmental chemistry, ranging from elemental cycling, to microbial fuel cells, to contaminant fate and remediation. Many of these redox processes are known to be strongly influenced by natural and artificial electron shuttles, but the role of interfaces in electron shuttle effects is hard to characterize and poorly understood. In additional to the laboratory research performed by graduate students, undergraduates, and high school interns, this project includes significant outreach activity with workshops for water industry professionals run by Clackamas Community College. One goal of these workshops is to better understand and utilize redox shuttle effects in the protection of safe drinking water.The approach of this project is to use electrodes as model systems for environmental interfaces. Electrodes are modified in various ways with electron shuttle compounds followed by measurement of redox processes using electrochemical instrumentation. The project scope includes different types of electrode materials (e.g., noble metals vs. iron oxide minerals), shuttle-electrode interactions (e.g., bonded vs. non-bonded), and shuttle types (quinones, flavins, porphyrins, siderophores, etc.). Interfacial effects on ETM properties will be studied using electrode-based model systems that allow systematic characterization of ETM-interface structure and reactivity. Electrode model systems will be used to represent three types of scenarios: (i) solution phase ETM effects only, vs. ETM-interfaceinteractions that are (ii) non-specific and non-bonded (i.e., ?outer-sphere?) or (iii) specific and bonded (i.e., ?inner sphere?). The surfaces will include electrodes made of glass carbon and gold (to isolate outer and inner-sphere interactions, respectively) and iron oxides grown on metallic iron electrodes (to represent environmental mineral surfaces). ETMs will be selected from four classes of environmentally important redox-active organics: quinones, flavins, porphyrins, and siderophores. Each system will be characterized electrochemically, primarily by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Complementary spectroscopic methods will be applied as needed: including UV-vis, FTIR, surface plasmon resonance (SPR) spectroscopy. Quantitative results (potential, current, impedance) will be used to derive properties of interfacial ETMs and these will be compared to values determined for solution-phase ETMs using various methods (experimental and computational). The overall results will be used to assess the overall significance of interfacial effects on environmental redox properties.

有了这个奖项，化学系的环境化学科学项目资助保罗·G·俄勒冈州健康科学大学的Tratnyek研究了被称为“电子穿梭”的物质如何在环境中的固溶体表面介导氧化还原反应的基本和应用方面。氧化还原（氧化还原）反应是环境化学中许多最重要的方面所不可或缺的，从元素循环到微生物燃料电池，再到污染物的归宿和修复。已知许多这些氧化还原过程受到天然和人工电子穿梭的强烈影响，但界面在电子穿梭效应中的作用难以表征且知之甚少。除了由研究生，本科生和高中实习生进行的实验室研究外，该项目还包括由Clackamas社区学院为水行业专业人员举办的研讨会的重要外展活动。这些研讨会的目标之一是更好地理解和利用氧化还原穿梭效应保护安全饮用水。该项目的方法是使用电极作为环境界面的模型系统。用电子穿梭化合物以各种方式修饰电极，然后使用电化学仪器测量氧化还原过程。项目范围包括不同类型的电极材料（例如，贵金属对氧化铁矿物），梭-电极相互作用（例如，键合对非键合）和穿梭型（醌、黄素、卟啉、铁载体等）。ETM性能的界面效应将使用基于电极的模型系统，允许系统表征ETM界面结构和反应性进行研究。电极模型系统将用于代表三种类型的场景：（i）仅溶液相ETM效应，与（ii）非特异性和非结合（即，?外球面？）或（iii）特异性和键合的（即，?内球体？）。表面将包括由玻璃碳和金制成的电极（分别隔离外部和内部的相互作用）和在金属铁电极上生长的氧化铁（代表环境矿物表面）。ETM将从四类对环境重要的氧化还原活性有机物中选择：醌、黄素、卟啉和铁载体。每个系统将进行电化学表征，主要通过循环伏安法（CV）和电化学阻抗谱（EIS）。将根据需要应用补充光谱方法：包括紫外-可见光谱、FTIR、表面等离子体共振（SPR）光谱。定量结果（电位、电流、阻抗）将用于推导界面ETM的特性，并将其与使用各种方法（实验和计算）确定的溶液相ETM值进行比较。整体结果将用于评估环境氧化还原性能的界面效应的整体意义。