Synthesis of mesoporous ZSM-5 zeolites through desilication and re-assembly processes
- Authors
- Yoo, Won Cheol; Zhang, Xueyi; Tsapatsis, Michael; Stein, Andreas
- Issue Date
- Feb-2012
- Publisher
- ELSEVIER SCIENCE BV
- Keywords
- Desilication; ZSM-5; Mesoporous zeolite; Surfactant
- Citation
- MICROPOROUS AND MESOPOROUS MATERIALS, v.149, no.1, pp 147 - 157
- Pages
- 11
- Indexed
- SCI
SCIE
SCOPUS
- Journal Title
- MICROPOROUS AND MESOPOROUS MATERIALS
- Volume
- 149
- Number
- 1
- Start Page
- 147
- End Page
- 157
- URI
- https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/33221
- DOI
- 10.1016/j.micromeso.2011.08.014
- ISSN
- 1387-1811
1873-3093
- Abstract
- ZSM-5 zeolite crystals with secondary mesopores were synthesized by alkaline desilication and surfactant-induced re-assembly of dissolved species (i.e., silicates, aluminosilicates and zeolite crystal fragments) originating from the parent ZSM-5 crystals. The meso-zeolite products exhibit a dual-mesopore structure in which the smaller mesopores (ca. 3 nm) are attributed to surfactant-induced micelle formation involving dissolved species, and larger mesopores (ca. 10-30 nm) result from desilication processes occurring under the alkaline reaction conditions. The external surface area (i.e., the surface area due to mesopores, macropores and the external particle surface) of the meso-zeolite materials depends on the Si/Al ratio, the hydroxide concentration and the presence of surfactant, and it reaches values as high as 327 m(2) g(-1) when a surfactant is used. The crystallinity of the highest surface-area meso-zeolite is well preserved, maintaining values of ca. 83% (on the basis of micropore volume) or ca. 77% (on the basis of X-ray diffraction intensities) of the parent zeolite structures. Further physicochemical characterization by Al-27 and Si-29 magic-angle-spinning solid-state NMR spectroscopy, scanning and transmission electron microscopy, temperature-programmed ammonia desorption measurements, and inductively coupled plasma elementary analysis support the hypothesis that re-assembly of dissolved species of zeolite crystals occurred by surfactant-induced micellization, resulting in the high external surface area of the meso-zeolite materials. (C) 2011 Elsevier Inc. All rights reserved.
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