The adsorption of H2O and D2O on porous polystyrene adsorbents

Abstract

The adsorption of H2O and D2O on porous polymers, Chromosorb-102 (styrene-divinylbenzene copolymer) and MN-200 (supercross-linked polystyrene), was studied by gas chromatography. Test adsorbates used to study the properties of the surface of these polymers were n-alkanes (C6-C9), C6H6, and the polar compounds CHCl3, CH3NO2, CH3CN, (CH3)2CO, C2H5COOCH3, and (C2H5)2O. The experimental data on the retention of the sorbates were used to determine the contributions of dispersion and specific intermolecular interactions to the total energy of adsorption for the systems studied. The electron donor KD and electron acceptor KA characteristics of the surfaces of Chromosorb-102 and MN-200 were determined. The KD and KA values obtained allow these polymers to be classified as weakly specific adsorbents with the predominance of electron acceptor properties. The adsorption isotherms of H2O and D2O were measured at 55, 67, and 80°C. The dependences of the isosteric heats of adsorption Qst on adsorption values were determined. The conclusion was drawn that H2O interacted with the surface of the polymers by the adsorption mechanism, whereas absorption likely made a noticeable contribution to the retention of D2O.