纳米MCM-41分子筛微球的制备及结构表征

以十六烷基三甲基溴化铵为模板剂,正硅酸四乙酯为硅源合成MCM-41分子筛.利用XRD、SEM、FT-IR、TEM和N2吸附-脱附等表征手段探究不同的反应温度及老化时间对MCM-41分子筛形貌、粒径及结构的影响.结果显示:当反应温度在2080℃时,合成的纳米MCM-41分子筛的颗粒形貌呈球形,随着温度的升高,球形颗粒的直径逐渐增大,当温度升高到110℃时,MCM-41分子筛呈现出不规则的颗粒形貌;当老化时间为015h时,纳米MCM-41分子筛的单分散度较好,但随着老化时间的增加,粒径也在增加,同时颗粒团聚也比较严重.通过对纳米球形MCM-41分子筛形成机理的分析,得出合成纳米MCM-41分子筛微球的最优条件.

Preparation and structure characterization of nanospherical MCM- 41 molecular sieves

Nanospherical MCM -41 molecular sieves have been synthesized by using hexadecyl trimethyl ammonium bromide （ CTAB ） as templates and tetraethyl orthosilicate （TEOS） as silicon sources. XRD, SEM, FY - IR, TEM, and N2 adsorption - de- sorption isotherms were used to investigate the effects of the reaction temperature and aging time on the morphology and structure of the samples. The results show that the nanospherical MCM -41 particles can be obtained at reaction temperatures between 20 to 80~C. With the reaction temperature increasing,the diameter of the nanospheres increases. When the reaction temperature rea- ches 110~C, MCM -41 molecular sieves exhibit irregular particle morphology. With the aging time of 0 - 15 h, the dispersion of nanospherical MCM -41 molecular sieves is very good. However, as the aging time increases,the particle size is also increased, while agglomeration is also more serious. Besides, the optimal synthesis conditions of the nanospherical MCM -41 molecular sieves were obtained by analyzing their formation mechanism.