A solvation and electrostatic model has been developed for estimating electrolyte adsorption from physical and chemical properties of the system, consistent with the triple-layer model. The model is calibrated on experimental surface titration data for ten oxides and hydroxides in ten electrolytes over a range of ionic strengths from 0.001 M-2.9 M (Sahai and Sverjensky, 1997a). The model assumes the presence of a single type of surface site, >SOH. It is proposed that for a 1:1 electrolyte of the type M +L −, the logarithms of the adsorption constants ( K s,M + and K s,L − ) representing the equilibria > SO − + M aq + = > SO − − M + and> SOH 2 + + L aq − = > SOH 2 + − L − contain contributions from an ion-intrinsic component and a solvation component. According to Born solvation theory, log K s,M + and log K s, L − can be linearly correlated with inverse dielectric constant of the k-th mineral ( 1 ϵ k ) resulting in the equations log K s,M + = − δω M + 2.303 RT 1 ϵ k + log K ii,M + ″ and log K s,L − = − δω L − 2.303 RT 1 ϵ k + log K ii,L + ″ The ion-intrinsic part (log K ii ″ ) is a linear function of the inverse electrostatic radius ( 1 r e,j ) of the j-th aqueous ion, where, in general, j = M + or L −. The interfacial solvation coefficient ( Δ, Ω j ) associated with the solvation component is linearly related to the inverse effective radius ( 1 R e ,j ) of the adsorbed ion and to the charge ( Z j ) on the ion. The model is consistent with surface protonation constants ( K s,1and K s,2) calculated from experimental points of zero charge and values of ΔpK predicted from the Pauling bond-strength per unit bond-length ( s r >S−OH ) of the bulk mineral (Sahai and Sverjensky, 1997a), site-densities ( N s) from isotopic-exchange data, and outer-layer capacitance (C 2) equal to 0.2 F m −2. As a first approximation, we also find an empirical trend between capacitance (C 1) of the inner-layer and 1 (r e,ML ·ω ML ) where r e,ML is the electrostatic radius and ω ML is the solvation coefficient of the aqueous electrolyte. Taken together, these correlations enable the calculation of surface protonation and electrolyte adsorption at equilibrium from the properties of the mineral/ solution system.