adsorption isotherm data from [BL73], site protolysis reference [GS84] average values from literature of various iron oxides; FITEQL/MICROQL; 20+-0.5°C; original equation: »Fe-OH + H3PO4 = »Fe-H2PO4 + H2O with log K = 7.43, formation constant in aqueous solution: PO4<3-> + 3H<1+> = H3PO4 logK = 21.702 [GFFGN03]