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，普渡大学和威斯康星大学麦迪逊分校的Amisha Shah和Christina Remucal将分别研究涉及天然沃茨表面硫元素的化学反应。这些化学反应很重要，因为它们可以产生含有碳硫（C-S）键的小分子，然后这些小分子可以进入大气层。一旦进入大气层，小分子可以参与其他影响气候变暖和变冷的化学反应。很明显，将这些沃茨暴露在阳光下有助于形成碳硫物质，但该过程如何发生的细节仍不清楚，特别是关于水中的其他化学化合物如何影响该过程。 在这个项目中，Shah和Remucal博士将研究从天然沃茨中的前体产生硫化羰和二硫化碳的化学机制。 目前，从这些来源生产这些气体的全球硫预算模型不一致。 特别是，阳光是已知的，以提高这些有机硫物质的生产，但这种增强的机制仍然不清楚。 本研究的主要目的是发展一个更好的理解的基本化学机制负责的光生羰基硫和二硫化碳在自然沃茨。这些目标将通过使用反应器进行不同类型的实验室规模实验来实现，该反应器模拟阳光照射含有各种化学前体和反应物的水样。该项目的成果将包括向科学界、学生和公众宣传，教育他们了解水化学和光化学过程对气候的作用。该奖项反映了NSF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.