Adsorption at solid-liquid interfaces. II. Models of the electrical double layer at the oxide-solution interface

Abstract

An extension has been made to Gouy-Stern-Grahame models of the double layer on mineral oxide surfaces.1 In this work and an earlier paper,2 the Stern isotherm is used for adsorption of p.d. ions at the surface. This is essentially an inversion of the modified Nernst equation given by Levine and Smith.3 The development of the surface charge and potential is considered by two different but related methods. Comprehensive calculations show that the zeta potential of oxide systems may be reasonably simulated with such models but the calculated surface charge is much less than that found experimentally. It is suggested that a model in which this surface charge is incorporated into a gel layer may be more appropriate.