Applied Surface Science, Vol.255, No.12, 6397-6403, 2009
Effect of the thermal and hydrothermal treatment on textural properties of Zr-MCM-41 mesoporous molecular sieve
Zr-containing mesoporous molecular sieves were synthesized by hydrothermal method using cetyltrimethyl ammonium bromide as a template and sodium silicate and zirconium sulfate as raw materials. The structure and morphology of the synthesized samples were characterized via various physicochemical methods, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, solid state nuclear magnetic resonance (Si-29 MAS-NMR) techniques, thermal gravimetric-differential scanning calorimeter (TG-DSC) and N-2 physical adsorption, respectively. The effect of the different initial ZrO2:SiO2 molar ratio, the different thermal treatment temperature and the different hydrothermal treatment time on textural property was investigated. The experimental results reveal that the as synthesized samples possess a typical mesoporous structure of MCM-41. On the other hand, the specific surface area and pore volume of the synthesized Zr-MCM-41 mesoporous molecular sieve decrease with the increase of the amount of zirconium incorporated in the starting material, the rise of thermal treatment temperature and the prolonging of hydrothermal treatment time, the mesoporous ordering becomes poor. Also, when the molar ratio of ZrO2: SiO2 in the starting material is 0.1, the mesoporous structure of the Zr-MCM-41 mesoporous molecular sieve still retains after calcination at 750 degrees C for 3 h or hydrothermal treatment at 100 degrees C for 6 d, and have specific surface areas of 423.9 and 563.9 m(2)/g, respectively. (C) 2009 Elsevier B.V. All rights reserved.
Keywords:Zr-MCM-41 mesoporous molecular sieve;Synthesis;Characterization;Textural property;Thermal treatment;Hydrothermal treatment