两阶段晶化合成复合分子筛

Composite Molecular Sieves Synthesized by Two-stage Crystallization

采用低温与高温相结合的两阶段晶化方式合成了一系列ZSM-5(core)/SAPO-5(shell)双结构分子筛,研究了合成条件对核壳结构分子筛的形成及性质的影响,并采用X射线衍射、扫描电镜、X射线能量散射谱、红外光谱及N2静态吸附等手段对样品进行表征.实验结果表明,与直接高温晶化相比,两阶段晶化方式在短晶化时间内合成的复合材料中SAPO-5的结晶度较低,而合成纯SAPO-5分子筛的结晶度却明显较高;两阶段晶化的方式能适当促进核壳结构型复合分子筛的形成,减少SAPO-5的独立生长.

ZSM-5 （core）/SAPO-5 （shell） binary structure composite molecular sieves were synthesized by two-stage varying-temperature syntheses, which includes the lower first-stage temperatures and higher secondstage temperatures. The effect of syntheses conditions on the formation and character of core/shell structure zeolite was investigated. These synthesized samples were characterized by XRD, SEM, EDS, FTIR and N2- adsorption, respectively. In result, compared with the direct high temperature method, the crystallinity of SAPO-5 in composite is lower and that of alone SAPO-5 zeolite is higher by two-stage varying-temperature syntheses at shorter time. So two-stage varying-temperature syntheses can improve the formation core-shell structure zeolies, reduce amounts of self-existent SAPO-5 zeolite.