On the positions of rare earth cations in Y zeolites as studied by NMR relaxation of adsorbed molecules

NMR relaxation measurements of adsorbed molecules yield information about the occupation of cationic sites in Y zeolites by paramagnetic RE 3+ ions. In RECaNaY zeolites Ca 2+ ions, introduced before the RE 3+ ions, direct the latter to sites in the supercages. If the order of succession of exchange...

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Bibliographic Details
Published in:Journal of colloid and interface science 1984, Vol.98 (1), p.144-151
Main Authors: Winkler, Horst, Steinberg, Karl-Hermann, Kapphahn, Gerd
Format: Article
Language:English
Subjects:
Adsorbents
Chemistry
Exact sciences and technology
General and physical chemistry
Surface physical chemistry
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Summary:NMR relaxation measurements of adsorbed molecules yield information about the occupation of cationic sites in Y zeolites by paramagnetic RE 3+ ions. In RECaNaY zeolites Ca 2+ ions, introduced before the RE 3+ ions, direct the latter to sites in the supercages. If the order of succession of exchange is inverted, no such effect is observed. In a RENaY zeolite the RE 3+ ions preferentially occupy sites outside the supercages. Dehydration at 450°C in high vacuum or in air makes part of the RE 3+ ions leave the supercages, partly irreversibly. With increasing water coverage an increasing number of RE 3+ ions migrate back into the supercages.
ISSN:0021-9797
1095-7103
DOI:10.1016/0021-9797(84)90488-0