Phenomenological theory of pressure-driven transport of ternary electrolyte solutions with a common coin and its specification for capillary space—charge model

Abstract

Pressure-driven transport of ternary electrolyte solutions have been considered within the scope of irreversible thermodynamics. At small thermodynamic forces, a general solution for an n-ionic system has been obtained and, further, specified and examined for a ternary system with a common coion. With the help of the continuous version of irreversible thermodynamics, two further limiting cases have been considered, namely, one of large Peclet numbers and one of a small addition of one of the electrolytes. Thermodynamic results have been exemplified within the scope of the capillary space—charge model. Parameters which govern the separation of counterions have been examined as functions of fixed charge density, pore size, feed ionic strength, the ratio of counterion mobilities and charges. A significant separation of counterions with different mobilities and/or charges was predicted.