Why Direct or Reversed Hofmeister Series? Interplay of Hydration, Non-electrostatic Potentials, and Ion Size

Date

2009

Authors

Parsons, Drew
Bostrom, Mathias Anders
Maceina, T.J.
Salis, Andrea
Ninham, Barry

Journal Title

Journal ISSN

Volume Title

Publisher

American Chemical Society

Abstract

A modified Poisson-Boltzmann analysis is made of the double layer interaction between two silica surfaces and two alumina surfaces in chloride electrolyte. The analysis incorporates nonelectrostatic ion-surface dispersion interactions based on ab initio ionic excess polarizabilities with finite ion sizes. A hydration model for the tightly held hydration shell of kosmotropic ions is introduced. A direct Hofmeister series (K > Na > Li) is found at the silica surface while the reversed series (Li > Na > K) is found at alumina, bringing theory in line with experiment for the first time. Calculations with unhydrated ions also suggest that surface-induced dehydration may be occurring at the alumina surface.

Description

Keywords

Keywords: Ab initio; Alumina surface; Chloride electrolytes; Double-layer interaction; Electrostatic potentials; Hofmeister series; Hydration shell; In-line; Ion size; Poisson-Boltzmann analysis; Polarizabilities; Silica surface; Surface dispersion; Chlorine compou

Citation

Source

Langmuir

Type

Journal article

Book Title

Entity type

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Restricted until

2037-12-31