铝源前处理下合成条件对ZSM-35分子筛的影响

Effect of synthesis conditions on ZSM-35 zeolites under pretreatment of aluminum source

以硅溶胶和铝溶胶分别为硅源和铝源、吡啶为模板剂,采用铝源前处理方法合成ZSM-35分子筛。通过激光粒度仪(LPSA)、X射线衍射(XRD)、扫描电子显微镜(SEM)等表征手段,研究了前处理条件(碱量、温度)与合成条件(水铝比、模铝比、晶化温度和时间,硅铝比)对ZSM-35分子筛合成的影响。结果表明,前处理碱量和温度会影响铝源母液的粒度与分布状态,平均粒径较小的铝源母液有利于得到结晶度较高、片层形貌良好的ZSM-35分子筛;在最佳的铝源前处理条件下,调变水量、模板剂用量、晶化温度与时间等合成条件,在30~250的投料硅铝比范围内能够合成出高结晶度、高固收率的ZSM-35分子筛。

ZSM-35 zeolites were synthesized via pretreatment of aluminum source,using silica sol and aluminum sol as the silicon and aluminum source,and pyridine as the structure directing agent.The as-synthesized samples were characterized by LPSA,XRD and SEM.The effects of pretreatment condition(alkali dosage,temperature)and synthesis condition(H2O/Al2O3 ratio,Py/Al2O3 ratio,crystallization temperature and time,SiO2/Al2O3 ratio)on the synthesis of ZSM-35 zeolites were investigated.Results showed that alkali dosage and temperature of the pretreatment affect particle size and distribution of mother liquor of aluminum source.Mother liquor with smaller average particle size was conducive to obtaining ZSM-35 zeolites with higher crystallinity and good lamellar morphology.Synthesis condition,such as the water content,dosage of template agent,crystallization temperature and crystallization time,was adjusted under optimal aluminum sol pretreatment condition.ZSM-35 zeolites with high crystallinity and high solid yield were synthesized under feed SiO2/Al2O3 ratio of 30-250.