Anion Exchange Properties of Hydrous Metal Oxides. Analysis Based on Surface Complexation With Stability Constant Data Base

Abstract

Ion exchange properties of hydrous metal oxides (HMeOs) for weak base anions were discussed in terms of surface complexation using the metal-ligand stability constant data base at relatively high ionic strength. The selectivity sequences of anion were correlated comparatively well with the orders of first stepwise stability constants (K₁) of the corresponding metal-ligand complexes. Conditions whether inner sphere or outer sphere surface complex forms could be evaluated by the difference in the stability constant between the OH^-/X^- (X^-: anion) and OH^-/H₂O ligand exchange reactions. These calculations suggest that the anion exchange reaction of HMeO is controlled mainly by the interactions of anions or H₂O molecules with the central metal atoms.