Kinetic Investigations of NOx Chemistry Pertaining to the Global Nitrogen Cycle

Daniel Heintzelman, Anthony Rizzuto, Chemistry, Elon University, 100 Campus Drive, Elon N.C. 27244

Nitrogen containing compounds (NOx compounds) are of central importance to the global nitrogen cycle and the reactions in which they participate significantly impact many atmospheric processes and even influence global climate change. Despite this, the kinetic properties of many of the NOx reaction pathways remain incompletely understood. Of particular interest is nitrous acid (HNO2) and the multitude of atmospheric reactions in which it participates. Specifically, the rate of decomposition of HNO2 under atmospheric conditions and in aerosol particles is largely unknown.  This project aims to detail the kinetic processes involved in the decomposition of aqueous HNO2 using UV-Vis spectroscopy.  We show that the decomposition of HNO2 occurs via both first- and second-order reaction kinetics depending on the initial HNO2 concentration in solution.  This result implies the decomposition proceeds through two different mechanisms – a first order mechanism at low concentrations (< 50 mM) of HNO2 and a second order mechanism at high concentrations (> 200 mM). The measured rate constants for the low and high concentration regimes were found to be 0.0029 s-1 and 0.00022 L mol-1 s-1 respectively. Future studies will be conducted to elucidate the specific molecular mechanisms by which nitrous acid decomposes in the two concentration regimes

Additional Abstract Information

Presenter: Daniel Heintzelman

Institution: Elon University

Type: Oral

Subject: Chemistry

Status: Approved

Time and Location

Session: Oral 7
Date/Time: Tue 3:30pm-4:30pm
Session Number: 710
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