OSDA-free synthesis of MTW-type zeolite from sodium aluminosilicate gels with zeolite beta seeds

• Published in: Microporous and mesoporous materials Vol. 163; pp. 282 - 290
• Main Authors: Kamimura, Yoshihiro, Iyoki, Kenta, Elangovan, Shanmugam Palani, Itabashi, Keiji, Shimojima, Atsushi, Okubo, Tatsuya
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15.11.2012; Elsevier
• Subjects: Chemistry; Colloidal state and disperse state; Crystallization; Exact sciences and technology; General and physical chemistry; Ion-exchange; MTW-type zeolite; Organic structure-directing agent (OSDA)-free; Porous materials; Seed-assisted synthesis; Surface physical chemistry; Zeolite beta; Zeolites: preparations and properties; Zeolite beta; MTW-type zeolite; Organic structure-directing agent (OSDA)-free; Seed-assisted synthesis; Crystallization; Water; Nucleation; Impurity; Similarity; Adsorption isotherm; Aluminosilicates; Adsorption capacity; NMR spectrometry; Porous material; Precursor; Silica; Molecular sieve; Characterization; Synthesis; Desorption isotherm; Aluminium oxide; Scanning electron microscopy; Composition; (OSDA)-free; Rod; Crystals; Crystallinity; Zeolite; X ray diffraction; Ammonia; Sodium; Silicon oxides; Organic structure-directing agent; Morphology; Alumina; Hydrothermal condition
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2012.07.014

[Display omitted] ► Crystallization of MTW from Na-aluminosilicate gel using beta seeds. ► Organic structure-directing agent (OSDA)-free synthesis of MTW. ► Structural similarity between seed and target zeolite is essential for growth of MTW. ► Specific aluminosilicate precursors are essential for growth of MTW. Seed-assisted methods have provided a new route for the organic structure-directing agent (OSDA)-free synthesis of industrially valuable zeolites. In the present study, we have reported the discovery of the OSDA-free synthesis of ZSM-12 (MTW-type zeolite) by adding calcined zeolite beta seed crystals to the OSDA-free Na-aluminosilicate gel. Various parameters in this synthesis have been comprehensively investigated. Characterization by XRD, FE-SEM, ICP-AES, and 27Al MAS NMR showed that the obtained MTW products without impurity (SiO2/Al2O3=31.8–46.4) possessed high crystallinity and a well-defined rod-like morphology. Adsorption–desorption isotherm of water and NH3-TPD profiles of MTW product showed enough adsorption capacity for water and ammonia molecules, respectively. Moreover, considering the crystallization behavior of seeded and non-seeded Na-aluminosilicate gels, the following key factors were found for inducing the crystallization of MTW by zeolite beta seeds under the hydrothermal condition: the structural similarity between seeds and target zeolite, and the initial gel compositions that provide specific aluminosilicate precursors for the crystallization of MTW prior to the spontaneous nucleation of other zeolite. This methodology provides a promising approach toward designed syntheses of valuable zeolites under environmentally benign conditions.