Stability and hydrothermal synthesis of zirconium incorporated MCM-41 mesoporous molecular sieve

According to the initial molar ratios of ZrO2:SiO2(0.05, 0.1, 0.2 and 0.3, respectively), four zirconium incorporated MCM-41 mesoporous molecular sieves (ZrMCM-41) were synthesized under hydrothermal condition using cetyl trimethyl ammonium bromide(CTAB) as a template and sodium silicate and zirconium sulfate as raw materials. The structure and morphology of the samples were characterized via various physicochemical methods such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric-differential scanning calorimeter (TG-DSC) and N2 physical adsorption. The effects of the initial molar ratio of ZrO2:SiO2, the thermal treatment temperature and the hydrothermal treatment time on the pore structure were also investigated. Experimental results reveal that the as-synthesized samples possess a typical mesoporous structure of MCM-41 and have specific surface area in the range of 448.6-891.9 m2/g. On the other hand, with the increase in the zirconium content of the synthesized ZrMCM-41 mesoporous molecular sieve and the rise of thermal treatment temperature and the prolonging of hydrothermal treatment time, the mesoporous ordering gradually deteriorates and the Brunauer-Emmett-Teller (BET) specific surface area gradually decreases.