Rediscovering the problem of interpretation of chromatographically determined enthalpy and entropy of adsorption of different adsorbates on carbon materials. Critical appraisal of literature data.
Adsorbate-adsorbent and adsorbate-adsorbate interactions having decisive influence on the distribution of adsorbate between gas-solid phases in inverse gas chromatography (IGC) have been thermodynamically explained. Specific retention volumes, second adsorption virial coefficients and Kováts retention indices, likewise their dependencies on column temperature, T, number of carbon atoms, n(C) (or methylene groups CH(2)) and mutual ones have been briefly presented. The results of the molar differential enthalpy and entropy of adsorption obtained for different carbon materials employing inverse gas chromatography have been collected and interpreted. An attempt has been made to elucidate abnormal behaviour of the specific and net retention volumes, the second adsorption virial coefficients and the Kováts retention indices, e.g., the magnitudes on which the values of the afore-mentioned thermodynamic values have been determined and compared. The detailed analysis of the errors associated with the experimental parameters necessary for calculating retention volumes, second adsorption virial coefficients and Kováts retention indices has been presented.
Grajek
Henryk
H
Military Technical Academy, Department of Advanced Technology and Chemistry, Institute of Chemistry, Kaliski st. 2, 00-908 Warsaw, Poland. hgrajek@wp.pl
D000327:Adsorption; D000465:Algorithms; D002244:Carbon / Q000737:chemistry*; D002849:Chromatography, Gas / Q000379:methods*; D019277:Entropy
D002244:Carbon