CAREER: Molecular Mechanism of Atmospheric Mercury through Speciation-Resolved Experiments

职业：通过形态解析实验研究大气汞的分子机制

• 批准号: 1554777
• 负责人: Alexei Khalizov
• 金额: $ 66.69万
• 依托单位: New Jersey Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1554777&HistoricalAwards=false
• 关键词: CAREER; Molecular; Mechanism; Atmospheric; Mercury

This CAREER project is focused on developing a better understanding of atmospheric mercury. Mercury is a highly toxic pollutant released by fossil fuel combustion and waste incineration, primarily in the form of gaseous elemental mercury (GEM). GEM is involved in long-range transport that can result in the transfer of mercury to the oceans. This project will investigate the kinetics of mercury reactions in the atmosphere. The improved knowledge of mercury chemistry obtained by this project will be critical for assessing the environmental impacts of mercury.The science objectives of the proposed research are to: (1) Elucidate the kinetics and mechanism of gas-phase reactions of mercury bromide (HgBr) to evaluate the lifetime of GEM and the molecular speciation of gaseous oxidized mercury (GOM); (2) Investigate the heterogeneous uptake of GOM on surfaces to improve understanding of the processes that form particle-bound mercury; and (3) Investigate ion-molecule reactions of GOM to identify reagent ions that can be utilized for direct detection of GOM in the atmosphere by chemical ionization mass spectrometry (CIMS). Questions that motivate this research include: (a) what atmospheric chemicals are responsible for the conversion of HgBr to stable gas-phase products? (b) What is the chemical nature of those products? (c) What are the rate coefficients of associated reaction pathways? (d) Which of the gas-phase products can bind effectively with atmospheric particulate matter? (e) Can these gas-phase and particle-bound products be detected and quantified directly?

这个职业项目的重点是更好地了解大气中的汞。汞是化石燃料燃烧和废物焚烧释放的一种剧毒污染物，主要以气态元素汞（GEM）的形式存在。GEM涉及远距离迁移，可能导致汞向海洋转移。该项目将研究大气中汞反应的动力学。本研究的科学目标是：（1）阐明溴化汞（HgBr）气相反应的动力学和机理，以评估GEM的寿命和气态氧化汞（GOM）的分子形态;（2）调查GOM在表面上的非均匀吸收，以提高对形成颗粒结合汞的过程的理解;（3）研究GOM的离子-分子反应，以确定可用于通过化学电离质谱（CIMS）直接检测大气中GOM的试剂离子。激发这项研究的问题包括：（a）大气中的哪些化学物质负责将HgBr转化为稳定的气相产物？(b)这些产品的化学性质是什么？(c)相关反应途径的速率系数是多少？(d)哪种气相产物能有效地与大气颗粒物结合？(e)这些气相和颗粒结合的产物是否可以直接检测和定量？