adsorption isotherm data from [AM79], solid called \"amorphous iron hydroxide\", site protolysis reference [GS84] (average values from literature of various iron oxides); FITEQL/MICROQL; FITEQL/MICROQL; original equation: »Fe-OH + H3PO4 = »Fe-PO4<2-> + H2O + 2H<1+> with log K = -0.65, formation constant in aqueous solution: PO4<3-> + 3H<1+> = H3PO4 logK = 21.702 [GFFGN03]