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以气相SiO2为硅源、四丙基铵(TPA)为模板剂,水热合成了Silicalite-1分子筛,考察了合成液的水量、碱度(Na2O含量)、四丙基铵(TPA)含量和晶化条件(合成时间和搅拌方式)对Silicalite-1分子筛晶体形貌和尺寸的影响,采用X射线衍射(XRD)、扫描电镜(SEM)、激光粒度仪(LLS)等技术对合成的Silicalite-1分子筛晶体进行表征。结果表明,减少水量和增大碱度可以使Silicalite-1晶体由棺形转变为球形,但碱度过高或过低时,分子筛晶体的产率很低;增加TPA浓度和缩短晶化时间可以减小Silicalite-1分子筛晶体的粒径,且均能获得较高的收率;不同的搅拌方式会影响晶体的粒径大小和分布,转动式合成能够得到粒径较为均一的晶体,而搅拌式合成能得到粒径分布较广的晶体,粒径相对较小。因此,通过调节合成液组成和合成条件,可以控制Silicalite-1晶体的形貌和尺寸。
Silicalite-1 molecular sieves were hydrothermally synthesized by vapor phase SiO2 as the silica source and tetrapropylammonium (TPA) as templating agent. The effects of water content, alkalinity (Na2O content), tetrapropylammonium (TPA) The effects of crystallization conditions (synthesis time and stirring method) on the morphology and size of Silicalite-1 molecular sieve were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser particle sizer (LLS) 1 molecular sieve crystal characterization. The results show that the decrease of water content and increase of basicity can make Silicalite-1 crystal change from coffin to sphere. However, when the alkalinity is too high or too low, the yield of molecular sieve crystal is very low. Increasing the concentration of TPA and shortening the crystallization time can The size of Silicalite-1 molecular sieve crystals can be reduced, and the yield of Silicalite-1 molecular sieve crystals can be high, and the yield of Silicalite-1 molecular sieve crystals can be higher. Different stirring methods will affect the crystal size and distribution, Synthesis can get a wider distribution of crystal size, particle size is relatively small. Therefore, the morphology and size of the Silicalite-1 crystals can be controlled by adjusting the composition of the synthesis solution and the synthesis conditions.