Exact statistical thermodynamics of alkane binary mixtures in zeolites: New interpretation of the adsorption preference reversal phenomenon from multisite-occupancy theory.-

M. DÁVILA; J. L. RICCARDO; A.J. RAMIREZ PASTOR

CHEMICAL PHYSICS LETTERS

ELSEVIER SCIENCE BV

Año: 2009 vol. 477 p. 402 - 405

0009-2614

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The rigorous statistical thermodynamics of mixtures of polyatomic species adsorbed on one- dimensional substrates is presented. The thermodynamic functions calculated for a monomer– dimer mixture are applied to describe the adsorption of methane ethane mixtures in zeolites. The theoretical formalism reproduces the main features of the system, showing that the displacement of ethane by methan at higher pressures, a phenomenon known as Adsorption Preference Reversal, is the result of the difference of size (or number of occupied sites) between the adsorbed species.