海泡石制备HMS和AlSBA介孔分子筛的研究

通过酸浸和模板合成处理，海泡石直接合成有序介孔二氧化硅和含铝的介孔二氧化硅. 海泡石用盐酸处理后120 ℃下在NaOH溶液中处理72 h, 得到具有HMS结构特征的介孔分子筛；在含铝的碱性溶液中处理后得到具有AlSBA结构的介孔分子筛. 并用SAXRD、BET、TPD表征了介孔分子筛的物相结构、比表面积、孔径分布和表面酸性. 两种介孔分子筛的比表面积分别为508 m2•g^-1和946 m2•g^-1，孔径分别为3.4 nm和3.9 nm，且孔径分布窄. NH3-TPD结果表明分子筛表面都有两个酸中心，随着Al原子的引入，表面酸性增强.

Preparation of HMS and AISBA Mesoporous Materials from Sepiolite

Ordered hexagonal mesoporous silica (HMS) and Al-containing hexagonal silica (AlSBA) are prepared directly from sepiolite using leaching and sequent template synthesis. The structure, surface acidity, and specific surface area of mesoporous materials are investigated by means of SAXRD, TPD, and BET adsorption methods. Mesoporous materials with features of HMS are prepared after the sepiolite is treated by 5 mol•L^-1 HCl acid solution and then kept in NaOH solution at 120 ℃ for 72 h. The ordered organization of materials improves with the formation of the AlSBA framework when modified-sepiolite is treated with NaAlO2 solution. Specific surface areas of HMS and AlSBA are 508 m2•g^-1 and 946 m2•g^-1, and the pore sizes are 3.4 nm and 3.9 nm, respectively. NH3-TPD results show that two acid centers appear on AlSBA and HMS surfaces, and the acidity and acid strength of acid centers in AlSBA are stronger than that of corresponding acidic centers in the HMS mesoporous materials.