Surface/bulk partitioning and acid/base speciation of aqueous decanoate: direct observations and atmospheric implications
2012 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, Vol. 12, no 24, 12227-12242 p.Article in journal (Refereed) Published
Dilute aqueous solutions of the atmospheric organic surfactant sodium decanoate have been studied using surface sensitive X-ray photoelectron spectroscopy combined with synchrotron radiation. We studied the decanoate/decanoic acid speciation and preferential adsorption at the vapor-liquid interface, and the responses to mixing in solution with some of the most common atmospheric inorganic ions, Na+, NH4+, Cl-, and SO42-. We observe little or no influence of Na+, Cl-, or SO42- ions, on neither the relative speciation nor the individual adsorption properties of decanoate and decanoic acid. In particular, no significant salting-out effect due to common Na+ cations of the organic and inorganic salts was observed for these solutions. On the other hand, mixing with NH4+ cations resulted in a pronounced surface enhancement of decanoic acid, which is attributed to surface specific acid-base chemistry. These changes in surface/bulk partitioning and surface speciation may significantly affect properties of aqueous droplets containing decanoate/decanoic acid, and potential implications for several processes critical to the climate effects of atmospheric aerosols are discussed.
Place, publisher, year, edition, pages
2012. Vol. 12, no 24, 12227-12242 p.
IdentifiersURN: urn:nbn:se:uu:diva-193047DOI: 10.5194/acp-12-12227-2012ISI: 000312666100030OAI: oai:DiVA.org:uu-193047DiVA: diva2:601077