The adsorption of anions of 3-hydroxy-2-naphthoic acid (HNA) from a berate
buffer of pH 7.4 on the surface of iron oxidized at 0.0 V is studied by the
ellipsometry technique coupled with electrochemical measurements and is de
scribed by the Frumkin isotherm. The joint adsorption of anions of HNA and
mepheneamino acid (MAA) is studied at high concentrations at 0.2 V. As oppo
sed to low concentrations of the mixture components (when joint adsorption
on passive iron increases), at a high coverage by one of these, this effect
is absent. At a high concentration of one component, adding identical amou
nt of the other makes no impact on the coverage by the former. The joint ad
sorption of anions of HNA and N-phenylanthranilic acid on passive iron is s
tudied at 0.0 and 0.2 V; the relevant isotherms and adsorption constants ar
e obtained. Variations in the ellipsometric angle Delta during adsorption o
f MAA and its mixture with HNA are examined.