Nernst–Planck modeling of multicomponent ion transport in a Nafion membrane at high current density

A mathematical model of multicomponent ion transport through a cation-exchange membrane is developed based on the Nernst–Planck equation. A correlation for the non-linear potential gradient is derived from current density relation with fluxes. The boundary conditions are determined with the Donnan e...

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Bibliographic Details
Published in:Journal of applied electrochemistry 2017-01, Vol.47 (1), p.51-62
Main Authors: Moshtarikhah, S., Oppers, N. A. W., de Groot, M. T., Keurentjes, J. T. F., Schouten, J. C., van der Schaaf, J.
Format: Article
Language:English
Subjects:
Boundary conditions
Cation exchanging
Chemistry
Chemistry and Materials Science
Convective flow
Current density
Electrochemical Processes
Electrochemistry
Industrial Chemistry/Chemical Engineering
Ion transport
Membranes
Physical Chemistry
Potential gradient
Qualitative analysis
Research Article
Tortuosity
Voltage drop
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Summary:A mathematical model of multicomponent ion transport through a cation-exchange membrane is developed based on the Nernst–Planck equation. A correlation for the non-linear potential gradient is derived from current density relation with fluxes. The boundary conditions are determined with the Donnan equilibrium at the membrane–solution interface, taking into account the convective flow. Effective diffusivities are used in the model based on the correlation of tortuosity and ionic diffusivities in free water. The model predicts the effect of an increase in current density on the ion concentrations inside the membrane. The model is fitted to the previously published experimental data. The effect of current density on the observed increase in voltage drop and the decrease in permselectivity has been analyzed using the available qualitative membrane swelling theories. The observed non-linear behavior of the membrane voltage drop versus current density can be explained by an increase in membrane pore diameter and an increase in the number of active pores. We show how the membrane pore diameter increases and dead-end pores open up when the current density is increased. Graphical Abstract
ISSN:0021-891X
1572-8838
DOI:10.1007/s10800-016-1017-2