Kinetic justification of the solubility product: application of a general kinetic dissolution model.
Using a simple, feldspar-like model and the crystal-based reaction mechanism for water-rock kinetics being developed before, we show directly how the dissolution of euhedral faces of crystals are governed by the nonlinear quantity represented by the solubility product. The kinetic approach requires recognition of the essential role played by the correlation of the dynamics of neighboring sites in a crystal, the statistical dynamics of steps, the coupling of the various kink sites on the surface by the crystal structure, and the inclusion of bond formation as well as bond rupture into the kinetic reaction mechanism. The same kinetic approach, which accounts for the role of the solubility product (or DeltaG) in the overall rate, is then shown also to explain the observed inhibition behavior in feldspars as well as the often-written phenomenological rate law, involving a product of a pH term, an activation energy term, and a DeltaG term.
Lasaga
Antonio C
AC
GeoKinetics, P.O. Box 1042, Lemont, PA 16851, USA.
Lüttge
Andreas
A
D000538:Aluminum Silicates / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D017680:Potassium Compounds / Q000737:chemistry*; D012995:Solubility
D000538:Aluminum Silicates; D017680:Potassium Compounds; C016447:feldspar