Aluminosilicate species in the hydrogel phase formed during the aging process for the crystallization of FAU zeolite

被引：117

作者：

Ogura, M ^{[1
]}

Kawazu, Y ^{[1
]}

Takahashi, H ^{[1
]}

Okubo, T ^{[1
]}

机构：

[1] Univ Tokyo, Dept Chem Syst Engn, Bunkyo Ku, Tokyo 1138656, Japan

来源：

CHEMISTRY OF MATERIALS | 2003年 / 15卷 / 13期

关键词：

D O I：

10.1021/cm0218209

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Faujasite zeolite is synthesized hydrothermally after an aging process under various conditions. Hydrogel is formed during the aging, and the amount increases with increasing the duration. Aluminosilicate species included in the hydrogel phase during the aging is investigated for the changes in Si/Al ratios and Q units during the aging and the crystallizing processes by means of Si-29 magic-angle spinning NMR spectroscopy. Aging for more than 1 day is necessary to obtain faujasite with high crystallinity. The distribution in Q(4) units in the hydrogel is gradually changed, and the aluminosilicate species having mainly a Q(4)(4Al) unit is obtained after 7 days of aging, while 2 days of aging results in remanent silicate species derived from the starting silica source. The former gives faujasite crystallites with higher crystallinity, sharper particle size distribution, and a lower Si/Al ratio. On the basis of these findings, the crystallization mechanism is discussed.

引用

页码：2661 / 2667

页数：7

共 25 条

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