Evaluation of the thermodynamic parameters for the adsorption of some n-alkanes on A type zeolite crystals by inverse gas chromatography

Inverse gas chromatography (IGC) has been used to evaluate the adsorption parameters (DeltaH, DeltaS and DeltaG) of some n-alkanes (n-C-5 to n-C-8) on 3A, 4A and 5A zeolites. The adsorption parameters of the probes on 4A were determined in the finite concentration region, and those on 3A and 5A were determined in the infinite dilution region. It was found that the adsorption isotherms for 4A conform with the Langmuir equation and the adsorption parameters increase linearly with increasing carbon number of the probes for 3A, 4A and 5A. Thermodynamic compensation effect between the adsorption enthalpy and entropy was observed. Also, heats of adsorption for 3A were found to be higher than those for 5A. (C) 2003 Elsevier Science B.V. All rights reserved.