A study of the adsorption thermodynamics of n-hexane on ion-exchanged X zeolites

Abstract

In this work, the free energy changes and entropy changes of adsorption of n-hexane on zeolites of the MxNa87-2xX (M=Co,Ni,Zn,Cd) type were determined using their isosteric sorption heats. It was found that the exchange of Na ions in NaX with bivalent cations (Co, Ni, Zn, Cd) significantly alters the adsorption characteristics of NaX zeolite. The free energy changes and entropy changes of n-hexane adsorption were dependent on the surface coverage and on the nature of the charge-balancing cation. The specific influence of the exchanged cations on the free energy changes and entropy changes of sorption of n-hexane originates from the size, location and electronic configuration of the cation.

U ovom radu su određene promene slobodne energije i promena entropije adsorpcije n-heksana na zeolitima tipa MxNa87-2xX (M=Co,Ni,Zn,Cd) na osnovu izosternih toplota sorpcije. Pokazano je da izmena Na+ jona u NaX zeolitu dvovalentnim katjonima (Co,Ni,Zn,Cd) značajno menja adsorpcione karakteristike NaX zeolita. Takođe je utvrđeno da promena slobodne energije i promena entropije adsorpcije n-heksana zavisi i od stepena pokrivenosti površine zeolita.