Application Of Concentrated Solution Theory To The Measurement Of Salt Transference Numbers In Ion-Selective Membranes

Models based on concentrated solution theory are developed to estimate t(+)(m) from anion-tracer and cation-tracer experiments. Markov Chain Monte Carlo (MCMC) algorithms are used to estimate the probability distribution functions for t(+)(m) accounting for uncertainties in other physical properties and experimental measurement. Under well-designed experimental conditions, t(+)(m) can be estimated precisely, and its value is consistent with estimates based on dilute-solution theory. The assumptions made in the concentrated solution theory model are tested with measurements of methanol flux, as a tracer for water flux. It is estimated that t(+)(m) = 0.935 +/- 0.005 for LiCl in Nafion 117 from anion-tracer experiments, while the estimates from cation-tracer experiments give t(+)(m) = 0.938 +/- 0.035. (c) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.