几种不同制备方法脱铝 Y 沸石的二次孔结构的表征

CHARACTERIZATION OF THE SECONDARY PORE SYSTEM ON Y ZEOLITES DEALUMINATED BY DIFFERENT METHODS

用氮吸附技术结合分析电镜技术对水热处理法,氟硅酸铵法和四氯化硅法等不同脱铝方法形成的脱铝 Y 沸石的孔结构进行了表征。水热处理法和四氯化硅法脱铝均匀,产生了均匀的二次孔和均匀的 Si/Al 比。氟硅酸铵法脱铝不均匀。水热处理法 USY 可形成约100×10^(-10)m 的二次孔。四氯化硅脱铝 Y 沸石基本不出现二次(中)孔。四氯化硅法和氟硅酸铵法的脱铝 Y 沸石能保持较高的结晶度。

Y zeolites dealuminated by steam,(NH_4)_2SiF_6 and SICl_4 have been chara-cterized by AEM and nitrogen adsorption.Different textures of the samples ha-ve been observed.Dealumination of Y zeolites by steam and SiCl_4 takes placehomogeneously throughout the grains with the formation of homogeneous se-condary pore system and with homogeneous Si/Al ratio.In contrast,the dealu-mination by(NH_4)_2SiF_6 is nonhomogeneous.The size of secondary pores onUSY is about 1×10^(-8)m.Generally,no secondary pores occur on the Y zeolitesdealuminated by SiCl_4.High crystallity can be maintained as Y zeolites aredealuminated by(NH_4)_2SiF_6 and SiCl_4