SPIN-LATTICE RELAXATIONS STUDY OF WATER MOBILITY IN NATURAL NATROLITE
M. Paczwa1, A.A. Sapiga2, M. Olszewski1, N.A. Sergeev1, A.V. Sapiga2
1University of Szczecin, Szczecin, Poland
2V.I. Vernadsky Crimean Federal University, Simferopol, Russia
Keywords: zeolite, NMR, natrolite, water mobility
Abstract
The mobility of water molecules in natural natrolite (Na2Al2Si3O10×2H2O) is investigated by the 1H NMR method. The spin-lattice relaxation times in the laboratory and rotating frames ( T 1 and T 1r) are measured as a function of the temperature for a polycrystalline sample. From experimental T 1 data it follows that at T > 286 K the diffusion of water molecules along channels parallel to the c axis is observed. From experimental T 1r data it follows that at T > 250 K the diffusion of water molecules in transversal channels of natrolite is also observed. At a low temperature ( T < 250 K) the dipolar interaction with paramagnetic impurities (presumably Fe3+ ions) becomes significant as a relaxation mechanism of 1H nuclei.
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