The competitive adsorption of water and toluene on KU-2-8 ion exchanger in the presence of aromatic amino acids

Abstract

The Weitkamp procedure was used to calculate hydrophobicity indices for several ion exchange systems, including adsorbed aromatic amino acids. The determination of hydrophobicity indices was based on the competitive adsorption of water and toluene from their mixture. Strongly acid KU-2 ion exchanger with hydrophilic properties predominantly sorbed water molecules in the competitive adsorption from their mixture with toluene vapor. The saturation of the ion exchanger with aromatic amino acids substantially decreased its sorption ability because of amino acid structuring and a decrease in permeability. The conclusion was drawn that the saturation of the ion exchanger with amino acids caused not only a decrease in the sorption of water but also a decrease in the sorption of hydrophobic toluene. This contradicted the assertion of an increase in hydrophobicity as a whole.