Collaborative Research: Evaluation of the Fundamental Photochemical Mechanisms Driving Carbonyl Sulfide and Carbon Disulfide Formation in Sunlit Natural Waters

在化学系环境化学科学（ECS）项目的支持下，分别来自普渡大学和威斯康辛大学麦迪逊分校的Amisha Shah和Christina remual将研究自然水体表面发生的涉及硫元素的化学反应。这些化学反应很重要，因为它们可以产生含有碳硫键（C-S）的小分子，然后这些小分子可以进入上面的大气。一旦进入大气，这些小分子就会参与影响气候变暖和变冷的其他化学反应。很明显，将这样的水暴露在阳光下有助于形成碳硫化合物，但这一过程如何发生的细节仍不清楚，特别是关于水中其他化合物如何影响这一过程。在这个项目中，dr。Shah和remual将研究从天然水域的前体中产生羰基硫化物和二硫化碳的化学机制。目前，从这些来源产生这些气体的全球硫收支模型是不一致的。特别是，已知阳光可以促进这些有机硫物种的产生，但这种增强的机制尚不清楚。本研究的主要目的是更好地了解自然水体中羰基硫化物和二硫化碳光产生的基本化学机制。这些目标将通过进行不同类型的实验室规模的实验来实现，使用一个模拟阳光照射含有各种化学前体和反应物的水样的反应器。该项目的成果将包括向科学界、学生和公众宣传水生化学和光化学过程对气候的作用。研究人员还将参与到初中和高中，并为本科生和研究生提供研究培训。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Environmental Chemical Sciences (ECS) Program in the Division of Chemistry, Amisha Shah and Christina Remucal of Purdue University and the University of Wisconsin-Madison, respectively, will study chemical reactions involving the element sulfur that occur at the surface of natural waters. These chemical reactions are important because they can produce small molecules containing carbon-sulfur (C-S) bonds that can then move into the atmosphere above. Once in the atmosphere, the small molecules can participate in other chemical reactions that impact climate warming and cooling. It is clear that exposing such waters to sunlight helps form the carbon-sulfur species, but the details of how the process occurs remains unclear, especially with regard to how other chemical compounds in water impact the process. In this project, Drs. Shah and Remucal will investigate the chemical mechanisms for production of carbonyl sulfide and carbon disulfide from precursors in natural waters. At present, models of the global sulfur budget for the production of these gases from these sources are inconsistent. In particular, sunlight is known to enhance production of these organosulfur species, but the mechanism for this enhancement remains unclear. The primary aim of this study is to develop a better understanding of the fundamental chemical mechanisms responsible for the photoproduction of carbonyl sulfide and carbon disulfide in natural waters. These goals will be met by conducting different types of lab-scale experiments using a reactor that simulates sunlight illuminating a water sample containing a variety of chemical precursors and reactants. Outcomes of this project will include outreach to the scientific community, students, and the public to educate them on the role aquatic chemistry and photochemistry processes have on the climate. The researchers will also engage in outreach to middle and high schools and provide research training to undergraduate and graduate students.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.