0000000000222358
AUTHOR
N. Pellenq
Confinement in micropores and enthalpies of physisorption
Abstract The use of quasi-equilibrium volumetry associated with isothermal microcalorimetry at 77 K allows direct measurement of the interactions on adsorption of simple probe molecules within well crystallised aluminophosphate and zeolite molecular sieves. Four particular cases are presented which show: the effect of varying micropore diameter, the effect of adsorbing molecules with a favourable geometric compatibility with a given micropore system, the effect of varying the field potential within a given micropore system and finally, the effect of variable selective blocking of the micropore system.
A microcalorimetric comparison of the effect ofn-alkane preadsorption on the adsorption of argon and nitrogen on Silicalite-I
Then-alkanes of different lengths were preadsorbed to selectively block part of the micropores of a MFI-type zeolite, Silicalite-I. The porosity available to argon and nitrogen was then studied by quasi-equilibrium adsorption microcalorimetry and volumetry at 77K and compared to what was found for the bare zeolite. Indeed, although partial adsorption ofn-alkanes does not alter the value of the differential enthalpies of adsorption for both argon and nitrogen, then-butane preadsorption diminishes the adsorption capacity by inducing inaccessible volumes in the micropore network. Moreover, the microcalorimetric experiments clearly show thatn-butane is not evenly distributed in the zeolite chan…