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Indexed by:期刊论文

Date of Publication:2016-07-01

Journal:MICROPOROUS AND MESOPOROUS MATERIALS

Included Journals:SCIE、EI

Volume:228

Page Number:86-93

ISSN No.:1387-1811

Key Words:Magadiite; Zeolite L; Conversion; Medium-range structure

Abstract:Zeolite L has been synthesized by magadiite conversion method. The crystallization behavior and changes of medium-range structure during the crystallization were investigated by X-ray diffraction, scanning electron micrograph, vibrational spectroscopy and Al-27 magic angle spinning nuclear magnetic resonance. It is indicated that parts of 6 member-rings in magadiite still exist as secondary building units although the long-range order of magadiite was collapsed in the initial stage. The 4 member-rings and 8 member-rings were formed after the sample was heated for 3 h and 4 h, respectively. The influence of various parameters such as reaction temperature, time and substrate composition was examined. Highly crystallized and pure zeolite L could be prepared from the substrates with molar composition: 0.56M(2)O -xAl(2)O(3) SiO2-49H(2)O (M2O = K2O + Na2O, x = 0.0033-0.04) by heating at 140 degrees C for 18 h, 160 degrees C for 12 h or 180 degrees C for 8 h. (C) 2016 Elsevier Inc. All rights reserved.