HCl处理后局部有序Y沸石的二次晶化

Recystallization of HCl-Treated Y Zeolite with Short Range Order

将商品 Y 型沸石用 HCl 处理后, 运用 X 射线粉末衍射, 透射电镜和扫描电镜、红外光谱及 27Al 和 29Si 魔角旋转核磁共振对其进行了表征. 结果表明, 酸处理后 Y 沸石接近无定形, 其长程有序性遭到破坏, 但还保留部分局部结构. 以不同浓度酸处理后的 Y 沸石为前驱体, 在 150 oC, 0.3 mol/L NaOH 条件下采用蒸汽辅助干胶转化法进行二次晶化, 可以获得丝光沸石, 其相纯度与前驱体的 Si/Al 密切相关. 随 Si/Al 比不同, 所得丝光沸石形貌由纳米针状堆积逐渐向微米单块状变化, 且其比表面积可达 400 m2/g 以上, 微孔孔容在 0.19 cm3/g.

A series of acid-treated Y zeolite crystals with different crystallinities were obtained by treating commercial Y zeolite in HCl solution.The acid-treated Y zeolites were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,Fourier transform infrared spectroscopy,and 27Al and 29Si MAS NMR.The results indicated that the acid-treated Y zeolites were almost amorphous but some short-range-order aluminosilicate species were retained.The acid-treated Y zeolites were recrystallized at 150 oC with 0.3 mol/L NaOH solution by the steam-assist crystallization method,and the pure mordenite zeolite products with the morphology from aggregate of nano-rod to micron-sized crystal were obtained within a suitable Si/Al ratio range.Their BET surface area is higher than 400 m2/g and micropore volume is up to 0.19 cm3/g.