RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

The intrinsic deprotonation constant (pK^int_a2) and the intrinsic ion exchange constants (pK^int_Me⁺) of Li⁺, Na⁺, and K⁺ on SiO₂ were uniquely determined at 30°C by using the potentiometric titration data, the Gouy–Chapman–Stern–Grahame (GSCG) model for the structure of the electrical double-layer (edl) and the double-extrapolation method. The values of these constants were pK^int_a2=6.57, pK^int_Li⁺=pK^int_Na⁺=pK^int_K⁺=5.61. The chemical meaning of intrinsic equilibrium constants and the equality in the values of pK^int_Li⁺, pK^int_Na⁺ and pK^int_K⁺ were discussed.