A thermodynamically consistent model for multicomponent electrolyte solutions

TL;DR

This paper develops a thermodynamically consistent mathematical model for multicomponent electrolyte solutions, integrating nonequilibrium thermodynamics with entropy and energy splitting to better understand mixing phenomena.

Contribution

It introduces a novel framework combining nonequilibrium thermodynamics with entropy splitting, enabling independent analysis of mixing and pure substance entropy in electrolyte solutions.

Findings

Derived evolution equations for entropy and energy parts.

Established explicit entropy production rate expressions.

Provided a comprehensive model for multicomponent electrolyte solutions.

Abstract

This paper presents a thermodynamically consistent model for multicomponent electrolyte solutions. The first part of this paper derives the general governing equations for nonequilibrium systems within the theory of nonequilibrium thermodynamics. Here, we consider electrolyte solutions as general mixtures of charged constituents. Furthermore, in this part of the paper we combine the general theory of nonequilibrium thermodynamics with the well-known splittings of the entropy and the energy into a pure substance part and a part due to mixing. Thereby, we successfully establish evolution equations for both parts. Furthermore, we derive for both parts explicit expressions of the respective entropy production rates. Hence, we provide an approach that allows to study the entropy of mixing independently of the pure substance entropy and vice versa. This is of great value, in particular for a better understanding of the complex phenomena due to mixing in multicomponent systems. In the second part of this paper, we close the system of general balance equations by applying constitutive laws. This is the crucial step in the modeling procedure. ...