中微双孔分子筛SBA-15的合成

采用P123(PEO20PPO70PEO20)为模板剂,正硅酸乙酯(TEOS)为硅源试剂,在强酸溶液中采用水热晶化法合成中微双孔分子筛SBA-15,并考察模板剂浓度、反应温度,离子导向剂和共溶剂对中微双孔分子筛SBA-15的影响.结果表明:控制合成温度可以精确调控SBA-15的介孔孔径;引入离子导向剂后合成的SBA-15具有更好的介孔有序性;加入共溶剂N,N-二甲基酰胺(DMF)会破坏SBA-15孔道的有序性,孔壁变薄,但可以提高分子筛的比表面积和孔容,大幅度提高孔径;采用乙醇后处理分子筛SBA-15有利于保持分子筛骨架.合成中微双孔分子筛SBA-15的合适条件为P123,TEOS,NaCl,HCl与H2O物质的量之比0.017∶1∶1.5∶9.86∶137,反应温度40℃,P123自组装反应时间4 h,与硅源组装老化时间24 h,晶化温度100℃,晶化48 h,在此条件下得到高质量的中微双孔分子筛SBA-15对苯吸附量接近1 000mg/g.

Preparation of Micro-Mesoporous Silica SBA-15

The micro-mesoporous molecular sieve SBA-15 was synthesized using P123 (PEO20PPO70PEO20)as template and tetraethoxysilanes (TEOS) as silica source by hydryothermal method, and the effects of the concentration of template, reaction temperature,ion directing agent and co-solvent (N,N-dimethylformamide,DMF) on micro-mesoporous molecular sieve SBA-15 were investigated.The results showed that the diameter of the micro-mesoporous molecular sieve SBA-15 could be controlled by changing reaction temperature, the order of the hexagonal phase of the molecular sieve was inceased by adding ion indirecting agent, and the surface, pore size and pore volume of SBA-15 were increased but the order array and wall thickness were decreased by adding DMF, and ethanol was suitable for maintaining the framework of SBA-15. The appropriate synthesis conditions for micro-mesoporous molecular sieve SBA-15 were molar ratio of P123 to TEOS, NaCl, HCl and H2O 0.017∶1∶1.5∶9.86∶137, reaction temperature 40 ℃, reaction time 4 h, aging time 24 h, crystallizing temperature 100 ℃, crystallizing time 48 h, and under the conditions the high quality micro-mesoporous molecular sieve was obtained and its absorption amount of benzene reached 1 000mg/g.