Elucidating Nitrogen and Chlorine Recycling Mechanisms from Multiphase Photochemistry of Oxidized Nitrogen

从氧化氮的多相光化学阐明氮和氯的回收机制

• 批准号: 2305078
• 负责人: Jonathan Raff
• 金额: $ 44.96万
• 依托单位: Indiana University
• 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: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305078&HistoricalAwards=false
• 关键词: Elucidating; Nitrogen; Chlorine; Recycling; Mechanisms

With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Jonathan Raff at Indiana University will study how the pollutant nitrate and other oxidized forms of nitrogen found on environmental surfaces (e.g., atmospheric particles, soil minerals, and sea salt) influence air pollution, which is a leading cause of premature death globally. There is significant evidence that interactions of nitrate with sunlight can change the composition of the atmosphere in ways that can lead to poor air quality or influence cloud formation. The chemical mechanisms involved are still not well understood. Laboratory experiments will be carried out on well-characterized models of soil, sea salt and aerosols using sensitive instrumentation that follows chemical reactions in real time and under real environmental conditions. This research will help clarify how pollutants in the atmosphere are formed and destroyed, with potential long terms scientific relevance to the causes of air pollution, particularly, to the nature of oxidized nitrogen species that might obtain in the atmosphere from nitrate chemistry. Graduate and undergraduate students will be involved in this research. The latter will include entering first-year students from underrepresented groups who will carry out summer research projects designed to increase their interest in pursuing science, technology, engineering and mathematics (STEM) majors. In addition, the outcomes of this project will be used in outreach activities to enhance science education at a local high school.Under this award, the research team led by Jonathan Ruff at Indiana University will study the photochemical reactivity of nitric acid, nitrate, and organic nitrates on environmental surfaces with a focus on elucidating chemical mechanisms leading to the release and recycling of nitrogen oxides and chlorine atom precursors that contribute to the oxidizing capacity of the atmosphere. Experimental approaches will involve UV-visible and infrared diffuse reflection spectroscopy, and photochemical flow reactors with gas phase product detection by chemical ionization mass spectrometry and chemiluminescence analysis. In addition to revealing mechanisms of nitrogen oxide and chlorine recycling, the project will provide the kinetics and photochemical data needed to advance the ability to model and predict multiphase photochemistry of oxidized nitrogen. The long term broader scientific impacts of this research include providing a more complete reaction tree emanating from atmospheric nitrates with a particular focus on the constellation of oxidized nitrogen species that is produced photochemically upon interaction with UV/vis light from the sun.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.

在化学系环境化学科学项目的支持下，印第安纳大学的乔纳森·拉夫将研究环境表面上发现的污染物硝酸盐和其他氧化形式的氮（例如大气颗粒、土壤矿物质和海盐）如何影响空气污染是全球过早死亡的主要原因。有重要证据表明，硝酸盐与阳光的相互作用会改变大气的成分，从而导致空气质量下降或影响云的形成。所涉及的化学机制仍不清楚。实验室实验将在土壤、海盐和气溶胶的良好表征模型上进行，使用灵敏的仪器在真实环境条件下实时跟踪化学反应。这项研究将有助于阐明大气中的污染物是如何形成和破坏的，与空气污染的原因具有潜在的长期科学相关性，特别是与硝酸盐化学可能在大气中获得的氧化氮物种的性质。研究生和本科生将参与这项研究。后者将包括来自代表性不足群体的一年级学生，他们将开展夏季研究项目，旨在提高他们对科学、技术、工程和数学 (STEM) 专业的兴趣。此外，该项目的成果将用于推广活动，以加强当地高中的科学教育。根据该奖项，印第安纳大学乔纳森·鲁夫领导的研究小组将研究硝酸、硝酸盐和硝酸盐的光化学反应性。环境表面的有机硝酸盐，重点是阐明导致氮氧化物和氯原子前体释放和回收的化学机制，这些前体有助于大气的氧化能力。实验方法将涉及紫外可见光和红外漫反射光谱，以及通过化学电离质谱和化学发光分析进行气相产物检测的光化学流动反应器。除了揭示氮氧化物和氯回收机制外，该项目还将提供所需的动力学和光化学数据，以提高建模和预测氧化氮多相光化学的能力。这项研究的长期更广泛的科学影响包括提供一个更完整的来自大气硝酸盐的反应树，特别关注与太阳紫外/可见光相互作用时光化学产生的氧化氮物种群。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。