Post-Synthesis Stabilization of Germanosilicate Zeolites ITH, IWW, and UTL by Substitution of Ge for Al

0467334 - ÚFCH JH 2017 RIV DE eng J - Journal Article
Shamzhy, Mariya - Eliášová, Pavla - Vitvarová, Dana - Opanasenko, Maksym - Firth, D. S. - Morris, R. E.
Post-Synthesis Stabilization of Germanosilicate Zeolites ITH, IWW, and UTL by Substitution of Ge for Al.
Chemistry - A European Journal. Roč. 22, č. 48 (2016), s. 17377-17386. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA ČR(CZ) GP14-30898P
Institutional support: RVO:61388955
Keywords : alumination * ITH * IWW
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 5.317, year: 2016

Germanosilicate zeolites often suffer from low hydrothermal stability due to the high content of Ge. Herein, we investigated the post-synthesis introduction of Al accompanied by stabilization of selected germanosilicates by degermanation/alumination treatments. The influence of chemical composition and topology of parent germanosilicate zeolites (ITH, IWW, and UTL) on the post-synthesis incorporation of Al was studied. Alumination of ITH (Si/Ge=2-13) and IWW (Si/Ge=3-7) zeolites resulted in the partial substitution of Ge for Al (up to 80%), which was enhanced with a decrease of Ge content in the parent zeolite. In contrast, in extra-large pore zeolite UTL (Si/Ge=4-6) the hydrolysis of the interlayer Ge-O bonds dominated over substitution. The stabilization of zeolite UTL was achieved using a novel two-step degermanation/alumination procedure by the partial post-synthesis substitution of Ge for Si followed by alumination. This new method of stabilization and incorporation of strong acid sites may extend the utilization of germanosilicate zeolites, which has been until now been limited.
Permanent Link: http://hdl.handle.net/11104/0265452