铝源对合成ZSM-5分子筛晶粒大小及形貌的影响

分别采用偏铝酸钠、硫酸铝、异丙醇铝为铝源,四丙基氢氧化铵为模板剂,用水热合成法制备了不同晶粒大小及不同形貌的ZSM-5分子筛.通过XRD、SEM等表征手段对各种锚源合成的分子筛结晶度、晶粒大小及形貌进行了对比分析.结果表明,以偏铝酸钠和异丙醇铝为铝源合成的ZSM-5分子筛晶粒较小,形貌趋于球形,且化学硅铝比与晶化前驱体的硅铝比基本一致;而以硫酸铝为铝源合成的ZSM-5分子筛硅铝比低于投料硅铝比,且晶粒较大.

Effect of aluminium sources on crystal size and morphology of ZSM-5 zeolite

Three kinds of aluminium sources,e.g.sodium aluminate,aluminum sulfate,aluminium isopropoxide(AIP)are used to synthesize ZSM-5 zeolites with different crystal gazes and morphology by hydrothermal method,with tetrapropylammonium hydroxide as a template.The products are inspected by X-ray diffraction and scanning electron microscopy.The results show that products synthesized with sodium aluminate and AIP as aluminium sources have smaller particle size and exhibit spherical shape,and the SiO_2/Al_2O_3 ratios in ZSM-5 zeolite and in precursor gel ore found to be consistent.While using aluminum salfate as a aluminium source.the particle size is larger and the SiO_2/Al_2O_3 ratios in ZSM-5 zeolite are lower than that in precursor gel.