Ionic partition equilibrium in a charged membrane immersed in a mixed ionic solution

Abstract

In partition equilibria of Ca²⁺, K⁺ and Cl^– between a swollen charged membrane and an aqueous bath of mixed KCl and CaCl₂ electrolytes, the equilibrium concentration of the bivalent ion in the membrane decreases to a minimum value as its concentration in the bath increases. The value of the concentration minimum decreases with increasing KCl : CaCl₂ concentration ratio in the bath. Simulations and analysis have been performed on the basis of Donnan distribution theory.