Synthesis and Characterization of Al MCM-41 Mesoporous Molecular Sieves

Al MCM-41 mesoporous molecular sieves were synthesized by a hydrothermal method at 110 degrees C using the cationic surfactant cetyltrimethylammonium bromide as a template, sodium silicate as the silicon source, and pseudoboehmite as the aluminum source. The obtained Al MCM-41 molecular sieve was characterized by X-ray powder diffraction (XRD), N-2 adsorption-desorption, solid-state Si-29, Al-27 magic angle spinning nuclear magnetic resonance (MAS NMR), scanning electron microscopy (SEM), and pyridine adsorption in Fourier transform infrared (FTIR) spectroscopy. The results showed that the Al MCM-41 molecular sieves had an ordered hexagonal packed structure, high relative crystallinity, high BET surface area, large pore volume, and a narrow pore size distribution. Furthermore, strong bonding between the silicon atoms in the Al MCM-41 framework resulted in good crystallization. The presence of the four-coordinate aluminum in the framework resulted in higher acidity.