MICROWAVE ABSORPTION AND STRUCTURE OF ZEOLITE WATER IN HEULANDITE AND CLINOPTILOLITE BY 1H NMR
S. P. Gabuda1, S. G. Kozlova1, A. S. Kolesnikov1, A. K. Petrov2
1A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences
2V. V. Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Division, Russian Academy of Sciences
Keywords: 1Н NMR, zeolite water, heulandite, clinoptilolite, microwave absorption
Abstract
The structure of zeolite water in single crystals of natural zeolites represented by clinoptilolite Na2K2Ca[Al6Si30O72]×22H2O and heulandite Са3Mg[Al8Si28O72]×24H2O is studied with 1H NMR. Below 170 K the distribution of H2O over the structural positions is shown to be fixed but different for the two minerals. Above 290 K translational and orientational diffusion of zeolite water molecules is observed and the structure of water is almost identical in both heulandite and clinoptilolite. Diffusion mechanism may be associated with the interaction between librational modes of H2O and high-frequency oscillations of aluminosilicate framework. The microwave absorption is shown to be caused in certain conditions by this type of interaction.
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