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 sergeev@wmf.univ.szczecin.pl 2V.I. Vernadsky Crimean Federal University, Simferopol, Russia
Ключевые слова: zeolite, NMR, natrolite, water mobility
Страницы: 335-340
Аннотация
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.
DOI: 10.15372/JSC20160211 |