Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

Sumita Pennathur, Jesper Kristensen, Andrew Crumrine, Mathias Bækbo Andersen, Henrik Bruus, Kristian Lund Jensen

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Abstract

Nanochannel ion transport is known to be governed by surface charge at low ionic concentrations. In this talk, we show that this surface charge is dominated by hydronium ions arising from dissolution of ambient atmospheric carbon dioxide. By refining the electrokinetic model of the nanochannel conductance for low salt concentrations, we identify a minimum conductance value before saturation at a value independent of salt concentration in the dilute limit. Our model self-consistently couples chemical equilibrium models of the silica wall and the electrolyte bulk, and is parameterized by only the surface reaction equilibrium constant for silica/hydronium reactions. The model describes our experimental data with aqueous potassium chloride solutions in 165-nm-high silica nanochannels well, and furthermore, by comparing model predictions with measurements in bulk and in nanochannels with hydrochloric acid solutions, we verify its predictive power.
Original languageEnglish
Title of host publicationBulletin of the American Physical Society
Volumevol. 55, no 16
PublisherAmerican Physical Society
Publication date2011
Publication statusPublished - 2011
Event63rd Annual Meeting of the APS Division of Fluid Dynamics - Long Beach, CA, United States
Duration: 21 Nov 201023 Nov 2010
Conference number: 63
http://www.dfd2010.caltech.edu/

Conference

Conference63rd Annual Meeting of the APS Division of Fluid Dynamics
Number63
CountryUnited States
CityLong Beach, CA
Period21/11/201023/11/2010
Internet address

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