carbonate sorption data of [VL00] (open system p(CO2) in 0.1 M NaNO3) fitted to the surface complexation equilibria; original reaction equation in the article is given as 2 »Fe-OH<0.5-> + H2CO3 = (»Fe-O)2-CO<1-> + 2 H2Owith logK = 5.93; thermodynamic data: logK1 = -6.366 for the reaction H2CO3 = H<1+> + HCO3<1->[FNK96], logK2 = -10.329 for HCO3<1-> = H<1+> + CO3<2-> [GFFGN03] --> so for H2CO3 = 2H<1+> + CO3<2-> the logK = -16.695