Coupled Diffusion of Multiple Ionic Species in Ion-Exchange Membranes with Fixed Ionic Groups

Abstract

The theory of coupled diffusion of multiple ionic species based on complete Donnan exclusion has been applied to a diffusion process involving an ion-exchange membrane and three counter ions. The influence of the main process parameters (e.g., diffusion coefficients and ionic charges) has been studied by numerical simulations. The results obtained underline the importance of taking into account the coupled diffusion of all counter ions in a multi-ion system to describe adequately the transport of each individual counter ion.

Keywords:

• Coupled diffusion
• Ion transport
• Ion-exchange membrane
• Mathematical modeling

Acknowledgments

The author is grateful to Prof. Robert W. Cattrall and Assoc. Prof. Terence J. Cardwell from the Department of Chemistry, La Trobe University for valuable discussion and helpful remarks.