Synthesis And Characterization Of STW And ITH-type Zeolite

This paper introduces the synthesis and characterization of B-and Ge-substituted STW-type silicate zeolite（denoted as B-STW,GeSi-STW-HT and GeSi-STW-DG）,ITH-type germanosilicate（denoted as GeSi-ITH）,Cu-and Co-containing ITH-zeotype（denoted as Cu-ITH and Co-ITH）.The specific research content are as follows:1.Pure B-STW were synthesized using 2-ethyl-1,3,4-methylimidazole hydroxide solution as organic structure-directing agent（OSDA）in the concentrated sol.The B-STW were characterized by powder X-ray diffraction（XRD）,inductance coupled plasma emission spectrometry（ICP）,scanning electron microscopy（SEM）,N₂ adsorption-desorption,Fourier transform infrared spectroscopy（FT-IR）,and NH₃ temperature-programmed desorption（NH₃-TPD）analysis methods.The effects of synthetic gel composition（the molar ratio of SiO₂/B₂O₃,the concentration of 2E134 TMIOH solution and crystallization time）were studied.2.STW-type silicagermanium were synthesized using N,N’-diethyl ethylenediamine as OSDA by hydrothermal synthesis method and dry-gel method,respectively,and namely as GeSi-STW-HT and GeSi-STW-DG.The GeSi-STW-HT and GeSi-STW-DG were characterized by powder XRD,ICP and SEM.3.GeSi-ITH were synthesized using tetramethyl hexanediamine as OSDA by hydrothermal synthesis method.The GeSi-ITH were characterized by powder and single crystal XRD,ICP,SEM,DT-TGA and N₂ adsorption-desorption.The effects of synthetic gel composition（H₂O,molar ratio of SiO₂/GeO₂,OSDA and fluorine ion）and thermal stability were studied.4.Cu²⁺ and Co²⁺ were introduced into the GeSi-ITH（denoted as Cu-ITH and Co-ITH）,which was by UV-visible diffuse reflectance spectra（DR UV-Vis）and X-ray photoelectron spectroscopy（XPS）analyses.The effects of synthetic gel composition（the content of Cu and Co）and thermal stability were studied.