Surface charge of silver iodide and several metal oxides. Are all surfacesnernstian?

Charge titration data for silver iodide, titanium dioxide, aluminum oxide, silica dioxide and ferric hydroxide are analyzed using a generic site bindi ng model that has the Nernst equation as a limiting form. Both the hypernet ted chain and the nonlinear Poisson-Boltzmann approximations are used to re late the diffuse double-layer potential to the surface charge, and a zeroth -order Stern layer is used to give the surface potential. In all cases it i s shown that in the vicinity of the point of zero charge the Nernst equatio n accurately gives the surface charge. (C) 2000 Academic Press.