Adsorption of m-xylene on prehydrated zeolite BaX: Correlation between temperature-programmed desorption and low-temperature neutron powder diffraction studies
C. Pichon et al., Adsorption of m-xylene on prehydrated zeolite BaX: Correlation between temperature-programmed desorption and low-temperature neutron powder diffraction studies, LANGMUIR, 16(4), 2000, pp. 1931-1936
Adsorption of m-xylene on partially hydrated zeolite BaX is studied by ther
mogravimetry, mass spectrometry, temperature-programmed desorption and neut
ron diffraction for different m-xylene loadings of the zeolite. Macroscopic
and microscopic measurements, for both molecules, were correlated and rela
tionships were found between the crystallographic positions of the adsorbed
molecules on the zeolite and macroscopic properties such as the number and
the area of the peaks in the desorption spectra for m-xylene or water. The
influence of water molecules on the adsorption phenomenon of m-xylene on B
aX zeolite was characterized. In particular, it was shown that the increase
of the filling of the prehydrated zeolite with m-xylene leads to a rearran
gement of the adsorbed aromatic molecule on its adsorption site. This displ
acement produces a weakening of the m-xylene-adsorbent interactions. It was
also shown that the filling of the zeolite BaX with m-xylene modifies the
distribution (and the energy of activation for desorption phenomenon) for w
ater molecules, but not the location of the water adsorption site.