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Indexed by:期刊论文

Date of Publication:2010-02-01

Journal:JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY

Included Journals:SCIE、EI、Scopus

Volume:85

Issue:2

Page Number:279-282

ISSN No.:0268-2575

Key Words:magadiite; offretite; recrystallization; tetramethylammonium cations

Abstract:BACKGROUND: This study was aimed at investigating the recrystallization of magadiite into offretite in the presence of tetra methylammonium cations (TMA). The offretite was characterized by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, N(2) adsorption analysis, thermogravimetry and differential thermal analysis. The influence of key reaction parameters on the formation of offretite, including reaction time, TMA cations, potassium cations and the SiO(2)/Al(2)O(3) reactant ratio, were examined.
   RESULTS: Well-crystallized offretite, which was composed of agglomerated samples, was prepared from a dispersion with the molar composition: 3.6 K(2)O: 3.6 Na(2)O: 1.0 Al(2)O(3): 6.5 SiO(2): 320 H(2)O: 1.5 TMA(+) by heating at 140 degrees C for 3 days. The structure of offretite collapsed when the temperature rose above 1000 degrees C. The organic template was removed when the sample was calcined at 550 degrees C for 10 h.
   CONCLUSION: Magadiite has been used to synthesize offretite with a high purity and well crystallized in the presence of tetramethylammonium cations. The results of the present study indicate the feasibility of a synthetic route to offretite through recrystallization of magadiite in the presence of tetramethylammonium cations. (C) 2009 Society of Chemical Industry