硼铝骨架改性中孔分子筛的合成与表征

Synthesis and Characterization of Mesoporous Molecular Sieves MCM-41 Modified in Framework by B and Al

以正硅酸乙酯(TEOS)为硅源,以十六烷基三甲基溴化铵(CTABr)为结构模板剂,在碱性条件下采用水热晶化法成功合成出B-Al骨架改性的中孔分子筛MCM-41。通过XRD、TG-DTG、IR、N2等温物理吸附等多种表征手段对其进行结构、性质分析; 发现B有助于Al进入Si-MCM-41中孔分子筛的无机骨架中,B-Al-MCM-41比Al-MCM-41的晶体完整性好;同时掺入B、Al后的中孔结构分子筛与全硅MCM-41中孔分子筛相比,无机墙表面基团的性质不同,比表面积稍小,最可几孔径稍大,孔径分布较宽;Al、B同晶取代Si进入MCM-41无机骨架会使其中孔结构发生一些变化,因而合成的B-Al-MCM-41必将有不同的催化、吸附性能。

Using tetraethylorthosilicate as silica source and hexadecry-trimethyl-ammonium bromide as template, the mesoporous molecular sieve silica MCM-41 modified by Al and B has been synthesized by hydrothermal synthesis method in basic media. The structure and properties of the material are investigated by using XRD, TG-DTG, IR, N2 physisorption technologies. It is found that B is able to promote Al to incorporate into the framework of mesoporous molecular sieve MCM-41, and the crystalline structure of B-Al-MCM-41 is more regular than that of Al-MCM-41. Compared with the MCM-41, the mesostructured B-Al-MCM-41 has different surface properties of inorganic wall, smaller surface area, larger pore diameter and broader pore distribution. The isomorphous replacement of Si by B and Al in the MCM-41 inorganic framework makes some changes in the pore structure, therefore, B-Al-MCM-41 may have different properties in using for catalysis and adsorption.