An analysis of the parameters in the Debye-Hückel theory

The Debye-Hückel theory is probably the most widely used option for counting the electrostatic forces in thermodynamic models. This work investigates the effects of the two most important parameters of the Debye-Hückel theory – the size parameters of ions and the relative static permittivity of the solution. Three different activity coefficient models are analyzed and compared for 14 salt systems in order to have a more complete picture of the capabilities and limitations of the Debye-Hückel theory. The three models are based on different assumptions for the two important parameters, but all with a self-potential term for the ion-solvent interactions. For the full version of the original Debye-Hückel theory, further analyses are made on the flexibilities of readjusting size parameters of ions and relative static permittivity.