海泡石制备介孔分子筛mcm41及其表征.docx

定性和表面酸性进行了研究。实验结果表明:镁含量对分子筛的热稳定性有很大的影响,镁含量少的样品(O%,%)有较高的热稳定性,坍塌温度达至U1030"12; 镁含量较大时(%),样品的热稳定性较差,在800℃结构坍塌。将Na-MCM-41 分子筛用1mol/L的NI-hCI溶液进行离子交换后进行吡啶吸附,然后测其红外光谱,考察t-I-。结果表明,在1448cml处有强吸收峰,样品有较强的L酸中心;含有镁的样品在1542 cm’1产处有较弱的吸收峰,产生了少量的B酸,
但仍以L酸为主。
关键词:介孔分子筛MCM-41, 海泡石,水热晶化,热稳定性,表面酸性
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ABSTRACT
Mesoporous molecular sieves have attracted considerable attention in the region ofchemical engineering,industrial catalysis,biomedicine,environmental protection,and fabrication of novel llano··object materials due to high surface area,well·-defined and
adjustable pore hydrothermal method is the most prevailing and
effective route for synthesis of mesoporous traditional silica-containing molecular sieves are prepared using water glass,tetraethoxysilane(TEOS)as silica resource consumption is ,attention has been paid to a new process to prepare mesoporons silica from natural clays.
The mesoporous molecular sieve MCM-41 Was synthesized by hydrothermal synthesis method wim post-Mg-extraction sepiolite as silica and hexadecyl— trimethylammonium bromide(CTAB)as mixture Was sti亦ed vigorously.
n把pH value of the slurry Was adjusted by NaOH resultant slurry was transferred into a Teflon-lined autoclave and reacted under appropriate crystallization,the solid produet Wns filtrated,washed with large anaounts of warln deionized water and finally calcined at 540℃for 4 h in air晰th a heating
rate of 3。C/min to obtain MCM- products were characterized by SAXRD、
BET、DSC、TEM、SEM and this paper,the effects ofcrystallization conditions (crystallization time,pH value,crystallization temperature and the ratio ofCTAB/Si02) on the formation of MCM一41,the reaction mechanism,the thermal stability and surface acidity were results are as follows:
(1)The effects of crystallization conditions On the formation of MCM-41 were:
①tI豫hexagonal MCM