The Synthesis And Charaterization Of Porous Materials ZSM-5,ZSM-35 And ZSM-39 Zeolites

Ordered porous materials have been intensively applied in many fields such as adsorption, ion exchange, and catalysis owing to their uniformity of pore system, modification of pore size, volume, crystal morphology and so forth. Recently, the synthesis, characteristic and application about ordered porous materials became hot topic on the international. In this paper, effects of fluoride ion on the synthesis of ZSM-35 zeolite were investigated by vapor phase transport method. Additionally, the roles of transition metals in synthesis of ZSM-35 zeolite were systematically investigated and the synthesis of ZSM-39 zeolite using vapor phase transport method was reported.Firstly, the effects of fluoride ion in the crystallization system of F^--SiO₂-Al₂O₃-H₂O were systematically studied using vapor phase transport method by means of the selectivity of reaction compositions, synthesis conditions such as crystallization time and temperature. Thesamples synthesized were characterized by the XRD, NMR, SEM, nitrogen adsorption, TG-DTA and FT-IR. The experiment results showed that ZSM-35 zeolite was synthesized when the chemical compositions of gels were 40NH4F-13.58SiO2-Al2O3-57.36H2O by vapor phase transport method, the compositions of liquid reaction mixtures was EDA/H2O=1.32, crystallization temperature and time were 493 K and 15 days respectively, the experiment results showed that fluoride ion played the roles of improving crystal size, increasing ZSM-35 zeolite surface area and framework Si/Al ratio.Secondly, we systematically investigated roles of transition-metal ion (such as Cr3+, Mn2+, Co3+, Cu2+, Zn2+, Pb2+) in the synthesis of ZSM-35 zeolite using vapor phase transport method. Samples synthesized were characterized by the XRD, FT-IR, UV-vis and SEM. The experiment results showed that Mn2+, Co3+, Cu2+, Zn2+ and Pb2+ could only alter the crystal size, crystal morphology and relative crystallinity of ZSM-35 zeolite, whereas the introduction of Cr3+ makes reaction compositions forming ZSM-5 zeolite instead of ZSM-35 zeolite. It implies that Cr3+ plays the roles that induced synthesis compositions to produce ZSM-5 zeolite, chromium was incorporated framework of ZSM-5 zeolite, altered the compositions of ZSM-5 zeolite synthesized; meanwhile ZSM-5 zeolite synthesized possessed high relative crystallinity, good crystal morphology and uniform crystal size.Lastly, we reported the synthesis of microporous ZSM-39 zeolite in the crystallization system of F"-SiO2-H2O using vaporphase transport method by using ?-propylamine as template agent, fumed silicate as silica source and ammonium fluoride as mineralizing agent. The samples synthesized were characterized by the XRD, SEM and FT-IR. The experiment results proved that ZSM-39 zeolite with high relative crystallinity, good crystal morphology and large crystal size was obtained from the reaction system of NH4F-Si2O-6.7H2O when the reaction time and temperature were 15 days and 493 K respectively.