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Sunlight-Induced Electron Ejection in Natural Waters

自然水中阳光诱导的电子弹射

基本信息

批准号：
0099027
负责人：
Oliver Zafiriou
金额：
$ 15.95万
依托单位：
Woods Hole Oceanographic Institution
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2001
资助国家：
美国
起止时间：
2001-04-01 至 2004-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0099027&HistoricalAwards=false
关键词：
Sunlight Induced Electron Ejection Natural

项目摘要

ABSTRACTOCE-0099027Although geochemists know that sunlight-induced photochemical reactions involving dissolved colored organic matter (CDOM) are ubiquitous in natural waters everywhere, observational difficulties have dictated that the detailed study of the underlying reaction mechanisms has been largely confined to the laboratory. The two principal laboratory techniques -- laser flash photolysis (LFP) and steady-state probes (SS-P) used to trigger photolysis imply reactions such asCDOM + hn @ CDOM+ + eaq-where hn represents a photon impinging upon a reactive site in the CDOM molecular structure, and eaq- is a hydrated electron ejected into solution as a consequence. However, investigators have been puzzled that LFP is significantly more efficient that SS-P in hydrated electron production. LFP is an important tool for photochemical research, so it is important to understand the discrepancy.In this project, researchers at the Woods Hole Oceanographic Institution, Brandeis University, and the University of Maryland combine efforts to re-evaluate the key reaction (above) by comparing LFP and SS-P data for samples from fresh and estuarine waters. The comparative studies would be calibrated using compounds with well-characterized photochemical properties, The focus would then shift to detailed comparative studies of estuarine and terrestrial CDOM fractions. If possible, unprocessed water samples would also be examined.

ABSTRACTOCE-0099027尽管地球化学家知道，涉及溶解有色有机物 (CDOM) 的阳光引起的光化学反应在世界各地的天然水域中普遍存在，但观测上的困难决定了对潜在反应机制的详细研究主要局限于实验室。两种主要的实验室技术——激光闪光光解 (LFP) 和用于触发光解的稳态探针 (SS-P) 意味着诸如 CDOM + hn @ CDOM+ + eaq 等反应，其中 hn 代表撞击 CDOM 分子结构中反应位点的光子，而 eaq- 是因此喷射到溶液中的水合电子。然而，研究人员感到困惑的是，LFP 在水合电子产生方面明显比 SS-P 更有效。 LFP 是光化学研究的重要工具，因此了解这种差异非常重要。在这个项目中，伍兹霍尔海洋研究所、布兰代斯大学和马里兰大学的研究人员共同努力，通过比较淡水和河口水域样本的 LFP 和 SS-P 数据来重新评估关键反应（上图）。比较研究将使用具有良好光化学特性的化合物进行校准，然后重点将转移到河口和陆地 CDOM 部分的详细比较研究。如果可能的话，还将检查未经处理的水样。