Peculiarities of structure in aqueous electrolyte solutions and specificity of hydration effects

A new approach to the hydration theory in aqueous solutions of electrolytes is developed. We show that the formation energy of one polarization complex is less than the thermal noise energy, as a result, polarization complexes are not stable. The notion of the effective polarization complex is introduced. It is connected with the concept of contraction of aqueous electrolyte solutions and certifies that the effective hydration number z does not exceed 3 divided by 4. This value agrees with the estimates obtained from the self-diffusion coefficients of ions and water molecules in aqueous solutions of electrolytes. We propose new theories for the kinematic shear viscosity of electrolyte solutions and self-diffusion of ions and water molecules in them. They have nothing in common with the activation approach, with the existence of voids in the water structure and with the quasi-Brownian character of ions displacements. We show that the kinematic shear viscosity is described by the formula which is typical for pure water and other argon-like liquids. The special attention is focused on the determination of a particle radii. The self-diffusion coefficients of water molecules and ions are considered to be the sums of two contributions, one of which has Einstein-like type and another is responsible for the collective drift in the fluctuation hydrodynamic field. We show that values of the self-diffusion and shear viscosity coefficients are inherently consistent with each other. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A new approach to the hydration theory in electrolyte solutions is proposed, introducing the concept of effective polarization complexes and showing their consistency with self-diffusion coefficients.