Thermal collapse and hierarchy of polymorphs in a faujasite-type zeolite and its analogous melt-quenched glass

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autor(en): Palenta T, Fuhrmann S, Greaves GN, Schwieger W, Wondraczek L
Zeitschrift: Journal of Chemical Physics
Verlag: American Institute of Physics (AIP)
Jahr der Veröffentlichung: 2015
Band: 142
ISSN: 0021-9606


Abstract


We examine the route of structural collapse and re-crystallization of faujasite-type (Na, K)-LSX zeolite. As the first step, a rather stable amorphous high density phase HDA(collapse) is generated through an order-disorder transition from the original zeolite via a low density phase LDA(collapse), at around 790 degrees C. We find that the overall amorphization is driven by an increase in the bond angle distribution within T-O-T and a change in ring statistics to 6-membered TO4 (T = Si4+, Al3+) rings at the expense of 4-membered rings. The HDA(amorph) transforms into crystalline nepheline, though, through an intermediate metastable carnegieite phase. In comparison, the melt-derived glass of similar composition, HDA(MQ), crystallizes directly into the nepheline phase without the occurrence of intermediate carnegieite. This is attributed to the higher structural order of the faujasite-derived HDA(collapse) which prefers the re-crystallization into the highly symmetric carnegieite phase before transformation into nepheline with lower symmetry. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.



FAU-Autoren / FAU-Herausgeber

Schwieger, Wilhelm Prof. Dr.
Professur für Technische Chemie (Reaktionstechnik)


Autor(en) der externen Einrichtung(en)
Friedrich-Schiller-Universität Jena
University of Cambridge


Zitierweisen

APA:
Palenta, T., Fuhrmann, S., Greaves, G.N., Schwieger, W., & Wondraczek, L. (2015). Thermal collapse and hierarchy of polymorphs in a faujasite-type zeolite and its analogous melt-quenched glass. Journal of Chemical Physics, 142. https://dx.doi.org/10.1063/1.4913240

MLA:
Palenta, Theresia, et al. "Thermal collapse and hierarchy of polymorphs in a faujasite-type zeolite and its analogous melt-quenched glass." Journal of Chemical Physics 142 (2015).

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Zuletzt aktualisiert 2018-05-07 um 01:23