A Debye-Huckel model for calculating the viscosity of binary strong electrolyte solutions

In this article we present a new model for correlating dynamic viscosity of binary strong electrolyte solutions. The proposed model is based on Eyring 's absolute rate theory and the Debye-Huckel model for calculating the exce ss (electrostatic) free energy of activation of the viscous flow. In the pr esent model we consider that the free energy of activation of the viscous f low as being the same as the appropriate thermodynamic free energy used for calculating equilibrium properties of the electrolyte solution. Modificati ons of Eyring's absolute rate theory must be performed to take into account the solvent as a continuous medium, as considered in the Debye-Huckel theo ry. This is accomplished by means of the osmotic-pressure framework for sol utions. In this framework one adopts a thermodynamic free energy, which is considered as a function of the absolute temperature, pressure, number of m oles of the solute species, and chemical potential of the solvent. The prop osed model contains two adjustable Parameters that have been fitted by mean s of experimental viscosity data of the literature. The total number of 21 binary electrolyte systems (at 0.1 MPa and 25 degreesC) with different solv ents (water, methanol, ethanol, and 1-butanol) have been studied. The calcu lated viscosity values are in good agreement with the experimental ones. Th e overall average mean relative standard deviation is 0.52%.