Adsorption of hydrofluorocarbons HFC-134 and HFC-134A on X and Y zeolites: Effect of ion-exchange on selectivity and heat of adsorption

Journal Article · Thu Sep 30 04:00:00 EDT 1999 · Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical

DOI:https://doi.org/10.1021/jp990560o· OSTI ID:20001136

Savitz, S; Siperstein, F R; Huber, R; Tieri, S M; Gorte, R J; Myers, A L; Grey, C P; Corbin, D R

Adsorption isotherms and heats of adsorption were measured for HFC-134 (1,1,2,2-tetrafluoroethane) and HFC-134a (1,1,1,2-tetrafluoroethane) on a series of ion-exchanged (H, Li, Na, Rb, Cs) faujasites using volumetric and calorimetric techniques. The species and number of ions present in the zeolite strongly influence the heats of adsorption and the preferential adsorption of HFC-134 compared to HFC-134a. The selectivity is considerably higher in X than in Y zeolites because of the larger number of nonframework ions in X zeolites. The saturation capacity is six molecules per supercavity for both HFCs. The differences in observed heats of adsorption (except for RbX) can be explained by reasonable and consistent values of dispersion and ion-dipole electrostatic energies. The high selectivities for NaX and RbX indicate that either zeolite would be highly effective for gas separation.

• Research Organization: Univ. of Pennsylvania, Philadelphia, PA (US)
• OSTI ID: 20001136
• Journal Information: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 39 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
40 CHEMISTRY
ADSORPTION HEAT
ADSORPTION ISOTHERMS
ION EXCHANGE
ORGANIC FLUORINE COMPOUNDS
REFRIGERANTS
ZEOLITES