AVS 65th International Symposium & Exhibition
    Applied Surface Science Division Thursday Sessions
       Session AS-ThP

Paper AS-ThP1
Toward an Improved Understanding of the role of soil organic matter in NOy cycling through Investigation of Heterogeneous Reactions with NO2+

Thursday, October 25, 2018, 6:00 pm, Room Hall B

Session: Applied Surface Science Division Poster Session
Presenter: Mark Engelhard, Pacific Northwest National Laboratory
Authors: R. Hansen, Indiana University
M.H. Engelhard, Pacific Northwest National Laboratory
J. Raff, Indiana University
Correspondent: Click to Email
Molecular level investigation of compositional changes due to heterogeneous reactions of nitrogen oxides (NOx, NOy) with soil organic matter (SOM) is important to develop a fundamental scientific understanding of the soil/atmosphere interface. In addition, interactions between NOx reservoir species and SOM play a more important role in NOx and NOy recycling than previously realized. Despite the importance of soil to the global terrestrial-atmospheric cycling of nitrogen, interactions of N2O5 with SOM are not well understood. Uncertainty in these processes is problematic because it means that NOy is not properly represented in the Earth-systems models used for prediction and regulation. The ultimate objective of this study is to investigate the production of NOy from the reaction of N2O5 with SOM and elucidate the mechanisms that return NOy back to the atmosphere, where NOy can contribute to aerosol and O3 formation. In the initial phase of this study, we reacted SOM standards with NO2+ (produced from concentrated HNO3), which is an intermediate in the heterogeneous reaction of N2O5 with SOM. We then characterized these reaction products using X-ray photoelectron spectroscopy (XPS). XPS was used to measure the nitrogen chemistry before and after reaction of SOM with NO2+. These results will be discussed along with the pros and cons using XPS to characterize SOM chemistry.