Crystallization mechanism of Fe-MFI from wetness impregnated Fe 2O3-SiO2 amorphous xerogels

Role of iron species in Fenton-like processes

J. A. Melero, G. Calleja, F. Martínez, R. Molina, K. Lázár

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The crystallization mechanism of Fe-MFI zeolite synthesized from amorphous Fe2O3-SiO2 xerogels wetness impregnated with aqueous TPAOH solutions has been studied. Samples with different degrees of crystallinity were prepared and characterized by means of conventional techniques. Activity and stability of these iron-containing samples has been tested in the catalytic wet peroxide oxidation (CWPO) of phenolic aqueous solutions. The crystallization mechanism involves a partial dissolution of the initial xerogel to yield an amorphous material. Nucleation and growth of the MFI phase is effected by reorganisation of the amorphous phase, although crystal growth also involves the incorporation of iron and silicon species during the last stage of the crystallization. A highly crystalline Fe-silicalite material is obtained after 3 h of synthesis at 170°C. Spectroscopic studies reveal that iron species are in framework positions (isomorphously substituted) in this highly crystalline material. In addition, the environment of Fe atoms as well as textural properties of the samples is dramatically modified along the crystallization affecting significantly to their catalytic activity and stability in CWPO processes.

Original languageEnglish
Pages (from-to)11-21
Number of pages11
JournalMicroporous and Mesoporous Materials
Volume74
Issue number1-3
DOIs
Publication statusPublished - Sep 20 2004

Fingerprint

Xerogels
xerogels
Crystallization
moisture content
Iron
crystallization
iron
peroxides
Peroxides
Crystalline materials
aqueous solutions
Oxidation
oxidation
amorphous materials
Zeolites
Crystal growth
catalytic activity
crystal growth
Silicon
crystallinity

Keywords

  • Catalytic wet peroxide oxidation
  • Crystallization mechanism
  • Fe-silicalite
  • Phenol
  • Wetness-impregnation

ASJC Scopus subject areas

  • Catalysis
  • Materials Science(all)

Cite this

Crystallization mechanism of Fe-MFI from wetness impregnated Fe 2O3-SiO2 amorphous xerogels : Role of iron species in Fenton-like processes. / Melero, J. A.; Calleja, G.; Martínez, F.; Molina, R.; Lázár, K.

In: Microporous and Mesoporous Materials, Vol. 74, No. 1-3, 20.09.2004, p. 11-21.

Research output: Contribution to journalArticle

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