AlMCM-41介孔分子筛的合成及表征

以拟薄水铝石为铝源、水玻璃为硅源、十六烷基三甲基溴化铵为模板剂,在110℃时水热晶化合成了含Al的MCM-41介孔分子筛.采用X射线衍射(XRD)、N2吸附-脱附、固体29Si、27Al魔角旋转核磁共振技术(MASNMR)、扫描电镜(SEM)及吡啶吸附傅里叶变换红外(FTIR)光谱技术对AlMCM-41分子筛进行了表征.结果表明:AlMCM-41分子筛具有六方排列的孔道结构,同时具有很高的相对结晶度、比表面积和孔容,且孔分布单一;AlMCM-41分子筛中Si原子在骨架内键合的程度更高,使AlMCM-41分子筛具有更好的骨架晶化程度;同时具有四配位骨架铝,使AlMCM-41介孔分子筛具有适当的酸性.

Synthesis and Characterization Of Al MCM-41 Mesoporous Molecular Sieves

Al MCM-41 mesoporous molecular sieves were synthesized by a hydrothermal method at 110 °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), N₂ adsorption-desorption, solid-state ²⁹Si, ²⁷Al 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.