以偏硅酸钠和硫酸铝为原料,采用直接合成法合成了ZSM-5/丝光沸石(mordenite,MOR)共生分子筛。通过X射线衍射和扫描电镜分析了合成样品的物相、形貌以及合成溶液中钠、铝含量和干基硅氧摩尔比的变化对ZSM-5/MOR共生分子筛样品结晶度的影响。结果表明:合成的样品是ZSM-5含量为90.3%,MOR含量为9.7%组成的ZSM-5/MOR共生分子筛,其大部分颗粒呈椭圆形和梭形。当合成溶液中n(Na):n(Al)=6,n(SiO2):n(Al2O3)≥20和n(O):n(Si)≥2.536时,合成的共生分子筛结晶度最好。在此基础上,提出了钠离子作为结构导向剂的合成机理。
ZSM-5/mordenite(MOR) intergrowth molecular sieves were synthesized by a direct synthesis method using sodium metasilicate and aluminum sulphate as raw materials.The composition and morphology of the samples,and the effects of sodium(Na) and aluminum(Al) content as well as the ratio of oxygen(O) to silicon(Si) in the solution on the degree of crystallization of the ZSM-5/MOR molecular sieves were investigated by X-ray diffraction and scanning electron microscope.The results show that the ZSM-5/MOR intergrowth molecular sieves are composed of ZSM-5 and MOR with 90.3%(in mass,the same below) and 9.7%,respectively,and the particles are elliptical and shuttle shaped.The ZSM-5/MOR molecular sieves have the best crystallinity when the mole ratio of Na to Al is 6,the mole ratio of SiO2 to Al2O3 is greater than 20 and the mole ratio of O to Si is greater than 2.536.Based on these results,we propose a synthesis mechanism is proposed in which Na acts as a structure-directing agent of the molecular sieve.