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Titolo:
Localization of water molecules and sodium ions in Na-mordenite, by thermally stimulated current measurement
Autore:
Devautour, S; Abdoulaye, A; Giuntini, JC; Henn, F;
Indirizzi:
Univ Montpellier 2, Lab Physicochim Mat Condensee, UMR 5617, CNRS, F-34095Montpellier 05, France Univ Montpellier 2 Montpellier France 05 , F-34095Montpellier 05, France
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 38, volume: 105, anno: 2001,
pagine: 9297 - 9301
SICI:
1520-6106(20010927)105:38<9297:LOWMAS>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXCHANGED MORDENITES; ADSORPTION; ZEOLITES; CATIONS; ELECTRONEGATIVITY; SIMULATIONS; RELAXATION; METHANE; ARGON;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Devautour, S Univ Montpellier 2, Lab Physicochim Mat Condensee, UMR 5617, CNRS, Pl E Bataillon, F-34095 Montpellier 05, France Univ Montpellier 2 Pl E Bataillon Montpellier France 05 ance
Citazione:
S. Devautour et al., "Localization of water molecules and sodium ions in Na-mordenite, by thermally stimulated current measurement", J PHYS CH B, 105(38), 2001, pp. 9297-9301

Abstract

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 selectivityof sodium ions and water molecules and on the other hand, the sodium/network interaction energy. Upon hydration, half of the Na+ ions remain embeddedin 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 pointedout that the interaction energy (Na+/zeolite) value depends on the sodium localization following the sequence: E-site A > E-site (D) > E-site (E). Finally, it is shown that the interaction energy decreases as the water content increases (typically from 0.79 eV to 0.44 eV). This evolution is successfully described by using a qualitative model referring to electronegativityand charge-transfer concepts.

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Documento generato il 13/07/20 alle ore 04:49:31