equilibrium constants in this study refer to site-occupancy standard state with hypothtical 1.0 M ionic strength (K°) and values for N' = 10 * 10^18 m^-2 and A' = 10 m²/g using the equation: K = K°(Ns * As/N' * A'), where Ns represents the SSD = 16.4 sites/nm² from [BM81] and As the SSA = 51.8 m²/g from [BM81]; regression of proton surface charge data in the present study; pH(ZPC) calculated from experimental pH(PZSE) = 7.5 [BM81] using equation 31