Synthesis And Characterization Of Mordenite Zeolite At Different Morphologies

Zeolites and related porous materials, which have ordered three dimensional frameworks and specific pore/channel structures, are widely used in many practical applications. Studies show that their properties and performances in adsorption, separation, iox-exchange and heterogeneous catalysis fields, are strongly affected by the crystal morphology. Thus controlling the shape and size of MOR zeolite has attracted much interest. But there are some disadvantages for synthesizing zeolite from chemical materials, such as the high cost. In this dissertation, based on lots of literatures of zeolites synthesis, hydrothermal synthesis of zeolite using diatomite as main silicon source had been studied in details. The effects of synthesis conditions to the crystallization of zeolites had been analyzed by using X-ray powder diffraction. On the basis of optimum synthesis conditions, the effects of different ancillary silicon source were studied in details. The main results are as follows.1. The zeolites with high crystallinity were studied with the diatomite as the main silicon source when the directing agent exist. The different influences on the crystalline of zeolite crystal, such as the aged time, the template amount and the water quantity of the structure directing agent, the crystallization time, the basicity and the water quantity of the zeolite synthesis system, had been researched systematically using the X-ray diffration. The optimum technological conditions of reaction are as follows.2.8Na2O:Al2O3:17SiO2:400H2O:2TEABr (tetraethylammonium bromide) is the molar ratio of the directing agent which is aged for16h at100℃.6Na2O:Al2O3:30SiO2:500H2O is the molar ratio of the reactant mixture for synthesizing the mordenite, which is crystallized for10h at170℃2. On the basis of optimum synthesis conditions, the effects of different ancillary silicon source were studied in details. The synthesizes sample were analysed through X-ray diffraction, scanning electron microscope and infrared spectrometer. The results show that mordenite with high crystallinity were synthesized using different auxiliary silicon source, the sample synthesized using fumed silica had the highest crystallinity; A series of mordenite with different morphologies were synthesized using different auxiliary silicon source, but their thermal stability were all above900℃...