Thermodynamics and Redox Reactivity of Birnessite

水钠锰矿的热力学和氧化还原反应性

• 批准号: 2304711
• 负责人: Christopher Gorski
• 金额: $ 42.53万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2304711&HistoricalAwards=false
• 关键词: Thermodynamics; Redox; Reactivity; Birnessite

With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Christopher Gorski and Peter Heaney and their graduate students at Pennsylvania State University will study chemical reactions that occur at the interface between minerals and water. These reactions are important because they play a significant role in determining how environmental contaminants, such as toxic metals and hazardous organic compounds, behave in the environment and in water treatment systems. The project focuses on birnessite, which is a highly reactive manganese oxide commonly found in the environment. The rate at which birnessite transforms environmental contaminants present in water can depend on the properties of the birnessite and the water chemistry, but there is currently no quantitative method for determining why. To address this gap, the project will characterize the elemental composition, oxidation state, crystal structure, aggregation state, and surface charge of birnessite in various types of water and determine how quickly different environmental contaminants react with birnessite under the same conditions. To broaden the societal and scientific impact of the project, the researchers will also develop a workshop to teach other scientists and engineers how to use electrochemical methods to study minerals, and organize a demonstration called “Mysterious Manganese Minerals” at an outreach event for grade 6-12 young women interested in STEM (science, technology, engineering and mathematics) fields.This project will use a combination of mediated electrochemical techniques, spectroscopic analyses, and contaminant fate studies to thoroughly characterize birnessite and its reactivity. The project has three objectives with sequentially increasing complexities: (1) to determine how and why the oxidation state of Mn in sodium birnessite influences its thermodynamic properties and reactivity at pH 5.0; (2) to determine how and why the type and concentration of cations in solution and the pH influence birnessite’s thermodynamic properties and reactivity and (3) to determine if the relationships developed in first two objectives can predict contaminant oxidation rates in complex waters containing multiple cations and/or natural organic matter. If successful, this work will provide the environmental chemistry and geochemistry communities with a method for estimating the thermodynamic properties of birnessite under a range of solution chemistries. The work will also create a framework for characterizing the thermodynamic properties of other complex environmentally relevant minerals in the future.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在宾夕法尼亚州的化学分区中的环境化学科学的支持下，研究将研究矿物质和水之间的界面上发生的化学反应。该项目的重点是在环境中发现的一种高度反应性的氧化锰基金会。晶体结构的ggrentation状态和不同类型水中的Birnessite的表面电荷与不同的环境污染物在相同条件下与Birnessite反应，以扩大项目的科学影响。 6-12对STEM感兴趣的年轻女性（科学，技术，工程和数学）领域。该项目将使用介导的电化学技术，光谱分析和污染物命运研究的组合来彻底表征其目标及其反应性。 ：（1）确定dium birnessite中Mn的氧气状态和pH 5.0时的反应性； ）确定在前两个目标中发展的关系是否可以预测氧化氧化的氧化氧化氧化，如果成功的情况下，这是一种疾病的氧化。在一系列溶液化学范围内的Birnessite也创建了一个框架，以表征将来其他相关矿物质的热力学特性。该奖项反映了NSF的冠军任务，并且值得支持基金会。