Synthesis and characterization of mesoporous silica from selectively acid-treated saponite as the precursors

Kiyoshi Okada, Hisako Yoshizaki, Yoshikazu Kameshima, Akira Nakajima, Chengala D. Madhusoodana

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Mesoporous silicas were synthesized by hydrothermal treatment of selectively acid-treated saponite (an ideal structural formula: Na1/3Mg3(Si11/3Al1/3)O10(OH)2), having a 2:1 type layered structure as the silica source and its porous properties were examined and compared with that from kaolinite (an ideal structural formula: Al2Si2O5(OH)4), having a 1:1 type layered structure. Synthetic saponite was selectively leached in H2SO4 solutions with various concentrations (0.05-1 M) at 70 °C for 0.5 h. The resulting products (precursors) were mixed with cetyltrimethylammonium bromide (CTABr), NaOH and H2O, hydrothermally treated at 110 °C and removed the CTABr by calcining at 560 °C. A hexagonal mesoporous phase was obtained with higher Si/(Al(+Mg)) ratios of the resulting precursors. The XRD patterns of these products show the peaks assigned by a hexagonal lattice with a0 = 4.0 - 4.6   nm and the crystallinity becomes higher with higher Si/(Al(+Mg)) ratios of the precursors. The specific surface area (SBET) values of the present mesoporous silicas range from 800 to 1100 m2/g at CTABr/precursor = 0.1 and although they are not as high as those from precursors prepared from calcining and acid-treatment of kaolinite (1420 m2/g), they are increased to 1400-1500 m2/g by increasing the ratio CTABr/precursor ≥0.2. The reason for the difference in the optimum preparation conditions between saponite and kaolinite may be attributed to the difference in the linkage of the SiO4 tetrahedra in these precursors (i.e. layered or framework structures), which result in great differences in the selective leaching rates and structures of the resulting silica-rich products.

Original languageEnglish
Pages (from-to)176-183
Number of pages8
JournalJournal of Colloid and Interface Science
Volume314
Issue number1
DOIs
Publication statusPublished - Oct 1 2007
Externally publishedYes

Fingerprint

Kaolin
Silicon Dioxide
kaolinite
Kaolinite
bromides
Silica
silicon dioxide
acids
Acids
synthesis
products
leaching
linkages
Specific surface area
tetrahedrons
Leaching
crystallinity
preparation
saponite
cetrimonium

Keywords

  • Acid-treatment
  • Cethyltrimethylammonium bromide
  • Mesoporous silica
  • Saponite

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Synthesis and characterization of mesoporous silica from selectively acid-treated saponite as the precursors. / Okada, Kiyoshi; Yoshizaki, Hisako; Kameshima, Yoshikazu; Nakajima, Akira; Madhusoodana, Chengala D.

In: Journal of Colloid and Interface Science, Vol. 314, No. 1, 01.10.2007, p. 176-183.

Research output: Contribution to journalArticle

Okada, Kiyoshi ; Yoshizaki, Hisako ; Kameshima, Yoshikazu ; Nakajima, Akira ; Madhusoodana, Chengala D. / Synthesis and characterization of mesoporous silica from selectively acid-treated saponite as the precursors. In: Journal of Colloid and Interface Science. 2007 ; Vol. 314, No. 1. pp. 176-183.
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