Adsorption and Chromatographic Characteristics of Graphitized Carbon Black, Modified by Adenine with Respect to a Series of Organic Compounds

Abstract

Graphitized carbon black, modified by 0.95% adenine, is selected as the main object of study. The thermodynamic characteristics of adsorption of a series of organic compounds on modified carbon black is investigated by inverse gas chromatography. Analysis of the resulting data shows that the additivity of molar changes in the internal energy of adsorption is violated in the considered sample, in a homologous series of n-alkanes and other compounds. In contrast to a series of adsorbents studied earlier, there is no violation of additivity for pairs, but there is for at least three members of the homologous series, testifying to the presence of cavities or voids with different sizes in the supramolecular structure of adenine. The sizes of the molecules for which the violation of additivity is observed allow us to estimate the sizes of the cavities in the supramolecular structure of adenine as 5.5–6 to 9–9.5 A. It was also found that modification by adenine increases the polarity of the surface. The use of adenine at Viedma ripening conditions provides the modified adsorbent the chiral recognition capability.