CAREER: Measurement of Photochemical Mechanisms, Rates, and Pathways of Radical Formation in Complex Organic Compounds

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With support from the Environmental Chemical Sciences (ECS) Program in the Division of Chemistry and the Established Program to Stimulate Competitive Research (EPSCoR), David C. Podgorski at the University of New Orleans and his students will study the process, length of time, and compounds that survive when hydrocarbon compounds are exposed to sunlight. Thousands of oil spills occur each year in U.S. waters. There are hundreds of thousands of chemical compounds in oil, and the products of their chemical transformation can have deleterious effects on human health and sensitive aquatic ecosystems. The energy from the sun can chemically break down the components released in such oil spills. There is a plethora of information about the breakdown and removal process of a couple of hundred small-size compounds in oil by the sun. However, knowledge is lacking about the chemical fate of the polyaromatic hydrocarbon (PAH) fraction, an important compound class in the oil. Project data will show how the sun removes these compounds from the environment and how long it takes. In addition, this project will provide training and mentoring to diverse students. High school students will be involved in research in the summer. Experiments will be performed to measure the chemical changes of complex organic compounds when subjected to simulated sunlight. The will be a particular focus on polyaromatic hydrocarbon (PAH) fraction and on the structure and distribution of oxidation products derived from irradiation of fused benzenoid systems. The chemical composition of degradation products will be measured by ultrahigh-resolution mass spectrometry and infrared spectroscopy. Chemical probe, spectroscopic, and laboratory pump-probe methods will be used to study photo-produced reactive transients. The effects of dispersant, solar irradiance, temperature, and chemical structure on the above processes will be determined. The work will inform stakeholders and provide workforce development training opportunities for high school, 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.