Identification and Quantitation of Gaseous Products in the Heterogeneous Reaction Between Nitric Acid and Bromide Salts
Presentation Type
Poster
Presentation Type
Submission
Keywords
Bromine, tropospheric ozone, aerosols, atmospheric chemistry, photochemical smog, infrared spectroscopy, UV-Visible spectroscopy, pollutants, multi-component Beer's law analysis
Department
Chemistry
Major
Chemistry
Abstract
Sea salt aerosols are injected into the atmosphere during wave action. These tiny droplets react with pollutants in the atmosphere to produce halogen-containing gases including Br2 and BrNO. In the presence of sunlight, these gases ultimately cause a net increase in tropospheric (ground level) ozone concentrations which negatively impact human health and Earth’s climate. Using both UV-Visible and IR spectroscopy, this in situ laboratory study probed the heterogeneous chemistry between nitric acid and sodium bromide, forming pollutant gases Br2, BrNO, HONO, NO, NO2 (and N2O4). Multi-component Beer’s law analyses were employed to quantify these product gases using absorption cross sections from the primary literature. IR temporal analyses of the autocatalytic reaction, facilitated using a custom Teflon-glass reactor system, show simultaneous growth of cis- and trans- HONO, BrNO, NO, and NO2, allowing a mechanism of the reaction to be proposed. This chemistry may be pertinent to acidified sea salt aerosols in the polluted troposphere as aging aerosols can become highly acidic during evaporation and interaction with atmospheric acids.
Faculty Mentor
Jane Ganske
Funding Source or Research Program
Academic Year Undergraduate Research Initiative, John Stauffer Charitable Trust, Summer Undergraduate Research Program
Location
Waves Cafeteria
Start Date
11-4-2025 1:00 PM
End Date
11-4-2025 2:00 PM
Identification and Quantitation of Gaseous Products in the Heterogeneous Reaction Between Nitric Acid and Bromide Salts
Waves Cafeteria
Sea salt aerosols are injected into the atmosphere during wave action. These tiny droplets react with pollutants in the atmosphere to produce halogen-containing gases including Br2 and BrNO. In the presence of sunlight, these gases ultimately cause a net increase in tropospheric (ground level) ozone concentrations which negatively impact human health and Earth’s climate. Using both UV-Visible and IR spectroscopy, this in situ laboratory study probed the heterogeneous chemistry between nitric acid and sodium bromide, forming pollutant gases Br2, BrNO, HONO, NO, NO2 (and N2O4). Multi-component Beer’s law analyses were employed to quantify these product gases using absorption cross sections from the primary literature. IR temporal analyses of the autocatalytic reaction, facilitated using a custom Teflon-glass reactor system, show simultaneous growth of cis- and trans- HONO, BrNO, NO, and NO2, allowing a mechanism of the reaction to be proposed. This chemistry may be pertinent to acidified sea salt aerosols in the polluted troposphere as aging aerosols can become highly acidic during evaporation and interaction with atmospheric acids.
