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Anion Fractionation and Reactivity at Air/Water:Methanol Interfaces. Implications for the Origin of Hofmeister Effects

Cheng, Jie and Hoffmann, Michael R. and Colussi, A. J. (2008) Anion Fractionation and Reactivity at Air/Water:Methanol Interfaces. Implications for the Origin of Hofmeister Effects. Journal of Physical Chemistry B, 112 (24). pp. 7157-7161. ISSN 1520-6106. https://resolver.caltech.edu/CaltechAUTHORS:20150623-154751053

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Abstract

Anions are selectively enriched in interfacial layers. This universal phenomenon, first identified in connection with protein precipitation 120 years ago, underlies fundamental processes. Its physical causes, however, remain conjectural. It has been speculated that the more polarizable anions should have larger affinities for air/liquid interfaces, and that their reactivities toward gaseous species would be affected by whether the liquid is capped by hydroxyl groups, as in water itself, or by hydrophobic layers of organic contaminants. These issues are particularly relevant to the composition and fate of atmospheric aerosols. Recently, we found that fractionation factors, f_(X^−), of simple anions at the air/water interface increase exponentially with ion radius, a_(X^−). In this paper, we report new experimental results on a set of anions that include the large PF_6^− and the highly polarizable IO_3^− species. A strict ln f_(X^−) ∝ a_(X^−) correlation is confirmed. Experiments performed in {x_wH_2O + (1 − x_w)MeOH} mixtures show that f_(X^−) is almost independent of x_w. Furthermore, O_3(g) oxidizes I^− at virtually identical rates on H_2O and MeOH.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp803184rDOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp803184rPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/jp803184rPublisherSupporting Information
ORCID:
AuthorORCID
Hoffmann, Michael R.0000-0001-6495-1946
Colussi, A. J.0000-0002-3400-4101
Additional Information:© 2008 American Chemical Society. Received: April 12, 2008; Revised Manuscript Received: May 13, 2008. This project was financially supported by the National Science Foundation (ATM-0534990).
Funders:
Funding AgencyGrant Number
NSFATM-0534990
Issue or Number:24
Record Number:CaltechAUTHORS:20150623-154751053
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150623-154751053
Official Citation:Anion Fractionation and Reactivity at Air/Water:Methanol Interfaces. Implications for the Origin of Hofmeister Effects Jie Cheng, Michael R. Hoffmann, and A. J. Colussi The Journal of Physical Chemistry B 2008 112 (24), 7157-7161 DOI: 10.1021/jp803184r
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:58461
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:29 Jul 2015 21:28
Last Modified:03 Mar 2020 13:01

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