Specific features of the adsorption and electrosorption of the isomers of amino- and hydroxybenzoic acids from aqueous solutions on carbon adsorbents

Some specific features of the adsorption and electrosorption of the isomers of amino- and hydroxybenzoic acids on nonpolarized and electrochemically polarized samples of P-709 Sibunit commercial mesoporous adsorbent were studied. The anomalously high adsorption and electrosorption of the m-isomers of the acids was explained by the fact that, at medium and high concentrations, adsorbate molecules are predominantly adsorbed so that the molecular plane is orientated perpendicular to the surface of the adsorbent. This behavior is associated with the field effect and the mesomeric effect in the molecule. The hydroxybenzoic acids are electrochemically oxidized at anodic potentials. At high anodic and cathodic potentials, the isomers of aminobenzoic acid yield products with more complex structures.