高岭土原位无溶剂法合成小粒径ZSM-5分子筛

Synthesis of Small Particle Size ZSM-5 Zeolite with Kaolin by in-Situ Solvent Free Method

结合原位水热法和无溶剂法的优点,在不添加有机模板剂和溶剂的基础上,以高岭土为原料通过晶种诱导绿色高效地合成出ZSM-5分子筛。运用X射线衍射、N2吸附-脱附、扫描电镜、透射电镜和NH3程序升温脱附(TPD-NH3)等技术对ZSM-5分子筛进行表征。表征结果与原位水热法合成的ZSM-5分子筛相比,原位无溶剂法合成ZSM-5分子筛的结晶度较高、晶体粒径较小、酸强度略高、孔结构相似。

By effectively combining in-situ crystallization and solvent-free method,the ZSM-5 zeolite was synthesized by seed induction and optimal synthesis conditions in a green and efficient manner on the basis of kaolin as raw material without adding organic template agent and solvent.The optimal synthesis conditions for the synthesis of ZSM-5 was:nNa2O/nSiO2 was 0.18~0.22,amount of seeds added was 5%(w/w)and reaction time was 70 h.The ZSM-5 zeolite was characterized by X-ray diffraction,N2 adsorption-desorption,scanning electron microscope,transmission electron microscope and NH3 programmed temperature desorption.Compared with ZSM-5 zeolite synthesized by hydrothermal method of in-situ crystallization,ZSM-5 zeolite by in-situ solvent free method obtained higher crystallinity,smaller crystal size,slightly higher acid strength and little difference in pore structure.In addition,the in-situ solvent-free method not only solved the problems of large pressure of the synthesis system and waste liquid discharge,but also improved the utilization rate of the reactor volume.