Cation site energies in high-silica FAU-type zeolites
| Autor: | Wilfried J. Mortier, Chao Kuei-Jung, Jan L. Lievens |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
chemistry.chemical_classification
Inorganic chemistry chemistry.chemical_element General Chemistry Crystal structure Cation distribution Faujasite engineering.material Condensed Matter Physics chemistry Aluminium X-ray crystallography engineering Physical chemistry General Materials Science Zeolite Inorganic compound Chemical composition |
| Zdroj: | Journal of Physics and Chemistry of Solids. 53:1163-1169 |
| ISSN: | 0022-3697 |
| DOI: | 10.1016/0022-3697(92)90034-b |
| Popis: | The statistical thermodynamical model by Van Dun, developed for the cation distribution in dehydrated FAU-type zeolites, has been investigated for the high-silica composition range. The Na distribution among the sites I, I' and II was determined using X-ray powder methods for dehydrated NaECR32 ( Si Al 4.9, fully exchanged), and dealuminated NaHY-type zeolites with Si Al ratios of 4.8 (NaLZ210, fully exchanged), 5.8, 9.9 and 21, respectively (the cation loading for all structures being approximately 50% of the CEC). The site-energy differences as a function of the framework Al content for the location of Na cations proposed by Van Dun were confirmed: (e1−e1 = −38.23 + 0.93Al (kJ mol−1) and e11−e1 = −45.23 + 0.93Al (kJ mol−1)). For high Si FAU-type frameworks the residual Na ions will always be located in the large cavity. This might be general for all zeolite structure types. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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