A further simplification of the revised physical adsorption (RPA) model

We present a further simplification of the essentially parameter-free revised physical adsorption model (K. Agashe, J.R. Regalbuto, J. Colloid Interface Sci. 185 (1997) 174) in this paper. It has been discovered that a physical adsorption model describing the uptake of various metal complexes from aqueous solutions onto oxide surfaces can most accurately simulate experimental data when the model contains only a coulombic energy term, and not a solvation energy term. The results of the simulation for cobalt/silica, chloroplatinic acid (CPA)/alumina, and tetraamonium platinate (TAP)/alumina and silica are presented here. A reasonable justification for the omission of this term is that solvation effects are negligible when adsorbing metal complexes retain one or more hydration sheaths. (C) 2003 Elsevier Inc. All rights reserved.