0000000000060848
AUTHOR
E. Pilverdier
Microporous volume and external surface of Y zeolites accessible to p-xylene and m-xylene
Abstract Isothermal adsorption of p-xylene and m-xylene on NaY, KY and BaY zeolites was studied by thermogravimetry at 25°C. Adsorption isotherms showed type H4 hysteresis associated with a xylenes adsorption process activated by the pressure. Experimental data were analysed with the t-method to distinguish the amounts of xylene adsorbed in the α-cages and on the external surface of crystallites. Results were compared with those previously achieved by calorimetry. Whatever may be the isomer and the Y zeolite, the adsorption capacity of α-cages at 25 °C is equal to 3.5 molecule α−1. At saturation, the amount of xylenes adsorbed on the external surface represents 13% of the total amount adsor…
Adsorption Properties of Nax and Bax Zeolites: Correlation between Structural and Thermodynamic Results on Para- and Meta-xylene Adsorption
A comparison is made between NaX and BaX adsorption properties starting from crystallographic data and thermodynamic measurements. Adsorption isotherms and differential adsorption heats of pure para- and meta-xylenes in NaX and BaX zeolites are interpreted in the light of crystallographic results.
Differential calorimetric enthalpies of adsorption ofp-xylene andm-xylene on y faujasites at 25°C
The differential enthalpies of adsorption ofp-xylene andm-xylene on NaY, KY and BaY zeolites were measured by isothermal calorimetry coupled with isothermal volumetry at 25‡C. Whatever the zeolite, the enthalpies of adsorption ofp-xylene andm-xylene at low filling were of the same order of magnitude. They did not show significantly the effect of the dipolar moment ofm-xylene. Their absolute values varied in the sequence