We demonstrate a synthesis method to broaden the range of SiO2/Al2O3 ratio (30-100) of high-silica MCM-22 zeolites by prolonging the aging time of the gel before the crytallization. The synthesis conditions such as si...We demonstrate a synthesis method to broaden the range of SiO2/Al2O3 ratio (30-100) of high-silica MCM-22 zeolites by prolonging the aging time of the gel before the crytallization. The synthesis conditions such as silica sources, chemical compositions of initial gel and aging time of gel were investigated in detail. High quality MCM-22 products with various morphologies have been synthesized by optimise their synthesis conditions. Our results show that increasing of the aging time can make the gel be homogenisation and promote their nucleus formation, which may avoid the for-mation of impurity phase and thus broaden the range of SiO2/Al2O3 ratio.展开更多
在无有机胺模板剂和不加晶种体系中,采用较低晶化温度(130℃),在水热体系中一步合成了形貌均一的板块状高硅ZSM-5沸石(nSiO2/nAl2O3>90)。系统地考察了合成体系中原料的物质的量之比对合成ZSM-5沸石的影响。通过X射线衍射(XRD),傅里...在无有机胺模板剂和不加晶种体系中,采用较低晶化温度(130℃),在水热体系中一步合成了形貌均一的板块状高硅ZSM-5沸石(nSiO2/nAl2O3>90)。系统地考察了合成体系中原料的物质的量之比对合成ZSM-5沸石的影响。通过X射线衍射(XRD),傅里叶红外光谱(FT-IR),扫描电镜(SEM),低温氮气吸附/脱附和固体核磁共振(29Si MAS NMR)等技术手段对合成的ZSM-5沸石进行了物化表征。结果表明,当原料的物质的量之比nC2H5OH/nSiO2=2.8、nNa2O/nSiO2=0.14和nSiO2/nAl2O3=150时,可合成具有高结晶度的ZSM-5纯相沸石。比表面积和微孔孔容分别为409 m^2·g^-1和0.14 cm^3·g^-1,其骨架nSiO2/nAl2O3达到96.4。展开更多
文摘We demonstrate a synthesis method to broaden the range of SiO2/Al2O3 ratio (30-100) of high-silica MCM-22 zeolites by prolonging the aging time of the gel before the crytallization. The synthesis conditions such as silica sources, chemical compositions of initial gel and aging time of gel were investigated in detail. High quality MCM-22 products with various morphologies have been synthesized by optimise their synthesis conditions. Our results show that increasing of the aging time can make the gel be homogenisation and promote their nucleus formation, which may avoid the for-mation of impurity phase and thus broaden the range of SiO2/Al2O3 ratio.
文摘在无有机胺模板剂和不加晶种体系中,采用较低晶化温度(130℃),在水热体系中一步合成了形貌均一的板块状高硅ZSM-5沸石(nSiO2/nAl2O3>90)。系统地考察了合成体系中原料的物质的量之比对合成ZSM-5沸石的影响。通过X射线衍射(XRD),傅里叶红外光谱(FT-IR),扫描电镜(SEM),低温氮气吸附/脱附和固体核磁共振(29Si MAS NMR)等技术手段对合成的ZSM-5沸石进行了物化表征。结果表明,当原料的物质的量之比nC2H5OH/nSiO2=2.8、nNa2O/nSiO2=0.14和nSiO2/nAl2O3=150时,可合成具有高结晶度的ZSM-5纯相沸石。比表面积和微孔孔容分别为409 m^2·g^-1和0.14 cm^3·g^-1,其骨架nSiO2/nAl2O3达到96.4。
