Localization of Water Molecules and Sodium Ions in Na-Mordenite, by Thermally Stimulated Current Measurement
| Autor: | François Henn, and J. C. Giuntini, S. Devautour, A. Abdoulaye |
|---|---|
| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 105:9297-9301 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp004268o |
| Popis: | Dielectric relaxation properties of dehydrated and hydrated Na-mordenite are measured by means of thermally stimulated depolarization current (TSDC) spectroscopy. TSDC spectroscopy allows us to determine two characteristic terms which depend on the hydration state: on one hand, the site selectivity of sodium ions and water molecules and on the other hand, the sodium/network interaction energy. Upon hydration, half of the Na+ ions remain embedded in site A, whereas the other Na+ ions are extracted from the main channel sites (sites D and E). Besides, according to the water content, we show that water molecules are adsorbed in different sites, first in sites H or F, then in sites B, C, or G, and finally in sites G. Furthermore, it is pointed out that the interaction energy (Na+/zeolite) value depends on the sodium localization following the sequence: Esite A > Esite D > Esite E. Finally, it is shown that the interaction energy decreases as the water content increases (typically from 0.79 eV to 0.44 eV). Thi... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|