Surface dissociation constants for solid oxide/aqueous solution systems

Summary An equation for the surface potential ₀ was used to define the surface dissociation constant of surface hydroxyls at a solid oxide/aqueous solution interface.Using the measurements of the surface charge, the Gouy-Chapman theory and crystallo-chemical data for oxides, the calculations of the surface dissociation constants have been carried out. The values of the acidic surface dissociation constants (in minus logarithmic scale) fall in range 8.7±0.8 at ionic strength 1 M and in the range 7.2±0.7 at 10^–3 M KNO₃ These constants exceed by 2 to 5 orders of magnitude the dissociation constants of M(OH)_naq species in solution.With 1 table