General Linearized Matrix Theory of Electrochemical Mass Transfer With Applications to Electrode Processes and Ion Exchange

Abstract

A general linearized matrix theory for electrochemical mass transfer is presented. The accuracy of the theory when applied to cases where electric current exists is tested by comparing results with exact calculations of the effect of ionic migration on limiting currents at a rotating disk electrode with laminar Rowand at a Rat plate electrode adjacent to a stagnant fluid film. Application of the theory is further illustrated by using it to calculate the effect of ionic migration on limiting currents in a turbulent, law-of-the-wall boundary layer. Finally, the theory is used to evaluate commonly used "film-model" methods for generalizing binary mass-transfer correlations to multicomponent non ideal mixtures. For this last purpose, a film-model generalization method was developed for non ideal electrolyte mixtures. The method is equivalent to that used by Krishnamurthy and Taylor (1985) for mass-transfer in nonideal nonelectrolyte mixtures. Results using the film-model method are compared to matrix calculations of multicomponent ion-exchange mass transfer across a laminar boundary layer and in fixed and fluidized beds.

Mixed-bed ion-exchange modeling with amine form cation resins

“…Both film models and matrix methods gave good agreement with exact calculations. Further work (Frey and Wong, 1989) describes the use of matrix theory for several applications including ion exchange. The matrix procedure was better them the film models for the concentration range of ÍO^-IO"1 mequiv/cm3, higher than the concentration range of interest for this model.…”

Tertiary Current and Potential Distribution Including Laminar/Turbulent Convection, Diffusion, and Migration by the Finite Volume Method Using OpenFOAM

“…Yen and Chapman reported on the effect of migration below the limiting current on a rotating disk electrode by the method of orthogonal collocation, replicating previous results. Different numerical methods for specific cases were proposed to calculate concentration, potential, and current distributions controlled by diffusion and migration of ions. − Georgiadou et al investigated the local mass-transfer rate along the bottom wall of two-dimensional cavities, concluding that migration accounted for 15% of the total mass transfer. Most recently, an open-source algorithm considering the convection, migration, and diffusion mechanisms was proposed for electrochemical copper deposition .…”