微波辐射法合成SAPO-5分子筛中硅铝比对产物结晶度和甲苯吸附性能的影响  

Effects of Si/Al Molar Ratio on the Crystallinity and Toluene Adsorption of SAPO-5 Synthesized under Microwave Radiation

作　　者：郝志显[1] 赵海涛[1,2] 王利军[2] 解丽丽[2] 田震[2] 李庆华[2] 

机构地区：[1]同济大学化学系,上海200092 [2]上海第二工业大学城市建设与环境工程学院,上海201209

出　　处：《物理化学学报》2009年第5期829-834,共6页Acta Physico-Chimica Sinica

基　　金：上海教委重点基金(06ZZ95);国家自然科学基金(50503011);上海市教育发展基金会晨光计划(2007CG72);上海重点学科项目(P1701)资助

摘　　要：采用硅溶胶作硅源,用微波辐射法在酸性条件下(pH=4.5-5.0)合成了SAPO-5分子筛,利用X射线衍射(XRD),傅立叶变换红外光谱(FT-IR),扫描电镜(SEM)和Brunauer-Emmett-Teller(BET)比表面积分析对样品的结晶度、形貌和比表面等进行表征,考察了晶化原料硅铝比对分子筛结晶度和晶体颗粒长径比(c/a)的影响,测定了分子筛对甲苯的吸附性能.结果显示,采用微波辐射法合成的SAPO-5分子筛,在硅铝摩尔比为0.50附近生成产物的结晶度最好,晶体颗粒的长径比最小(约为1.0).尽管不同硅铝比条件下得到的样品比表面测定结果变化不大,但对甲苯的吸附实验显示,在硅铝比为0.50时样品的吸附速率和饱和吸附量均达到了最大值.这与表征所得的结晶度和长径比的变化一致,即结晶度好,长径比小的SAPO-5分子筛具有更好的甲苯吸附性能.SAPO-5 molecular sieves were synthesized using high pressure microwave radiation and at pH=4.5-5.0. Effects of silica/alumina （Si/A1） molar ratios of the initial reaction sol-gel on the aspect ratio （c/a） of resulting crystal particles and the toluene adsorption capability of the products were investigated. X-ray diffraction （XRD）, Fourier transform-infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM） and Brunauer-Emmett-Teller （BET） surface area analyses showed that good crystallinity and low crystal aspect ratio were apparent at a Si/Al molar ratio of 0.50. The highest toluene adsorption rate and quantity was obtained at around the same Si/Al molar ratio of 0.50. BET surface areas were approximately constant despite the products were obtained under the reaction conditions of different Si/Al molar ratios. The agreement obtained from the characterization and adsorption indicates that SAPO-5 molecular sieves with high crystallinity and low aspect ratio are valuable for toluene adsorption.

关 键 词：SAPO-5分子筛 微波辐射法 硅铝比 结晶度 长径比 甲苯吸附 

分 类 号：O643.36[理学—物理化学]