Simulation of ionic transport in concentrated solutions using bi-velocity method

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2018-09, Vol.824, p.181-187
• Main Authors: Volgin, V.M., Lyubimov, V.V., Gnidina, I.V., Kabanova, T.B., Davydov, A.D.
• Format: Article
• Language: English
• Subjects: Approximation; Bi-velocity method; Computer simulation; Concentrated electrolyte solutions; Electrolytes; Finite volume method; Fluxes; Ionic transport processes; Mathematical models; Migration; Nernst-Planck equations; Simulation; Transport processes; Velocity
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2018.07.051

The work is devoted to the theoretical study of transport processes in the concentrated electrolyte solutions using bi-velocity method. The Nernst-Planck equations in the approximation of solution electroneutrality and the Vegard rule are used as the mathematical model. For one-dimensional case (a plane electrode in the stagnant or intensively stirred electrolyte solutions), a scheme of numerical solution based on the conservative finite volume method is developed. Within the framework of bi-velocity method, the equations for the diffusion-migration fluxes of the solution components and for the drift velocity are obtained. The results of simulation are presented and compared with the results obtained using the known method for dilute solutions. It is shown that ignoring the velocity induced by the ionic transport leads to a considerable error in the limiting current density up to tens of percent. •Analysis of transport processes in concentrated electrolyte solutions by bi-velocity method•Determination of hydrodynamic velocity induced by ionic transport using the scalar potential•Study of effect of concentration, diffusion coefficients and partial molar volumes on ionic transport