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Surface Formation Pathway of Nitrogen- and Sulfur-Containing Organic Compounds on Ammonium Sulfate

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Názov: Surface Formation Pathway of Nitrogen- and Sulfur-Containing Organic Compounds on Ammonium Sulfate
Autori: Chen, Jie Ping, Kisimbiri, George Wandera, Gladich, Ivan, Fauré, Nicolas, Thomson, Erik S., Temperton, Robert, Kanji, Zamin A., Kong, Xiangrui
Prispievatelia: Lund University, MAX IV Laboratory, MAX IV, Science division, Lunds universitet, MAX IV-laboratoriet, MAX IV, Vetenskapsavdelning, Originator
Zdroj: Journal of Physical Chemistry A. 129(12):2922-2931
Predmety: Natural Sciences, Earth and Related Environmental Sciences, Meteorology and Atmospheric Sciences, Naturvetenskap, Geovetenskap och relaterad miljövetenskap, Meteorologi och atmosfärsvetenskap, Chemical Sciences, Physical Chemistry (including Surface- and Colloid Chemistry), Kemi, Fysikalisk kemi (Här ingår: Yt- och kolloidkemi), Physical Sciences, Condensed Matter Physics (including Material Physics, Nano Physics), Fysik, Den kondenserade materiens fysik (Här ingår: Materialfysik, nanofysik)
Popis: The formation of nitrogen- and sulfur-containing organic compounds (N-Org and S-Org) is important for atmospheric secondary organic aerosol (SOA) production, thereby influencing air quality and global climate. However, the mechanisms underlying N-Org and S-Org formation on aerosol particle surfaces are poorly understood due to the limited availability of surface-sensitive analytical techniques. This study investigates the surface interactions of glyoxal (GL), a known SOA precursor, with ammonium sulfate (NH4)2SO4, under varying relative humidity (RH) conditions, using ambient-pressure X-ray photoelectron spectroscopy (APXPS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and molecular dynamics (MD) simulations. N-Org species, such as imines, a key intermediate in brown carbon (BrC) formation, are identified on the (NH4)2SO4 surface at low RH (≤13.3%). The formed S-Org species cannot be specified due to the difficulties in distinguishing S-Org from inorganic sulfate in the XPS spectra. Elemental ratios on (NH4)2SO4 surface across the entire probing depth show increased S/O and N/O ratios upon GL exposure, indicating the formation of N-Org and S-Org species. NEXAFS measurements further confirm the surface changes of (NH4)2SO4 associated with the adsorption of GL and water. These findings provide compelling evidence of surface-driven N-Org and S-Org formation pathways, demonstrating that heterogeneous reactions on (NH4)2SO4 particle surfaces could be an active source of atmospheric BrC and SOA.
Prístupová URL adresa: https://doi.org/10.1021/acs.jpca.5c00332
Databáza: SwePub
Popis
Abstrakt:The formation of nitrogen- and sulfur-containing organic compounds (N-Org and S-Org) is important for atmospheric secondary organic aerosol (SOA) production, thereby influencing air quality and global climate. However, the mechanisms underlying N-Org and S-Org formation on aerosol particle surfaces are poorly understood due to the limited availability of surface-sensitive analytical techniques. This study investigates the surface interactions of glyoxal (GL), a known SOA precursor, with ammonium sulfate (NH4)2SO4, under varying relative humidity (RH) conditions, using ambient-pressure X-ray photoelectron spectroscopy (APXPS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and molecular dynamics (MD) simulations. N-Org species, such as imines, a key intermediate in brown carbon (BrC) formation, are identified on the (NH4)2SO4 surface at low RH (≤13.3%). The formed S-Org species cannot be specified due to the difficulties in distinguishing S-Org from inorganic sulfate in the XPS spectra. Elemental ratios on (NH4)2SO4 surface across the entire probing depth show increased S/O and N/O ratios upon GL exposure, indicating the formation of N-Org and S-Org species. NEXAFS measurements further confirm the surface changes of (NH4)2SO4 associated with the adsorption of GL and water. These findings provide compelling evidence of surface-driven N-Org and S-Org formation pathways, demonstrating that heterogeneous reactions on (NH4)2SO4 particle surfaces could be an active source of atmospheric BrC and SOA.
ISSN:10895639
DOI:10.1021/acs.jpca.5c00332