Effect of excess silicate on the structure formation and textural properties of MTS materials
- 143 Downloads
The synthesis of micellar templated silica (MTS) materials has been conducted with different SiO2/CTAB molar ratios for two different cetyltrimethylammoniumbromide (CTAB) concentrations of 0.02 and 0.07 M to examine the structure formation for cubic (SBA-1) as well as for hexagonal (SBA-3) surfactant arrangement in acidic reaction medium with increasing silicate excess. Reaction products were analyzed with X-ray diffraction, N2 physisorption and TG-MS. It was found that an increase of the silicate concentration leads to the formation of additional silica gel in the resulting MTS material, which causes not only a decrease of specific surface area and pore volume, but also of the mesopore diameter. The latter effect is explained by a proposed embedding theory. Furthermore, with increasing silicate content in the synthesis mixture a phase transformation from hexagonal to cubic pore arrangement was found for the CTAB concentration of 0.07 M and the maximum SiO2/CTAB molar ratio for ordered pore arrangement has been determined.
KeywordsMicellar templated silica (MTS) Silicate excess SBA-1 SBA-3 Pore arrangement Textural properties
Financial support from the Fonds der Chemischen Industrie and the Deutsche Forschungsgemeinschaft (DFG) within the Cluster of Excellence “Engineering of Advanced Materials” is gratefully acknowledged.
- 6.R.K. Iler, The Chemistry of Silica (Wiley, New York, 1979), p. 185 fGoogle Scholar
- 9.R. Ryoo, C.H. Ko, I-S. Park, Chem. Commun. 1413 (1999)Google Scholar
- 12.C.C. Egger, M.W. Anderson, G.J.T. Tiddy, J.L. Casci, Phys. Chem. Chem. Phys. 7, 1845 (2005)Google Scholar
- 17.S. Munsch, Trennung von Aminosäuren aus wäßrigen Lösungen durch Adsorption an mikro- und mesoporösen Molekularsieben, PhD 2003, University Kaiserslautern, GermanyGoogle Scholar