Synthesis And Properties Of Zsm-5 Zeolite Membrane

ZSM-5 zeolite membranes are kinds of MFI with mid-pore (pores diameter are 0.55nm) zeolite membrane.ZSM-5 zeolite membranes have attracted much attention because of their unique characteristics, such as their thermal, resist-acidity, hydrothermal stability and fine catalysis properties compared to polymeric membranes, and their potential applications in the separation and membrane reactors.However, there are still some questions on the zeolite membrane prepartion. They are as follows: Most membrane are prepared on the supports with average of pore diameter under 0.2 μ m, which demand high quality supports and low permeances. There have not been studied on seeds peoperties and thermal decomposition system removing of organic templates agent. Poison-producing and high production cost, the contamination of waste water by organic templates agent, air pollution arising from thermal decomposition of organic templates agent, operation complexity and synthesis time long.On the basis of ZSM-5 membrane by in-suit hydrothermal synthesis, Some important factors are thoroughly studied on secondy synthesis ZSM-5 zeolite membrane in this thesis The higher permeability and the ideal separation factor of ZSM-5 zeolite membranes are synthesized on rough porous α -aluminum tube with average pore size of 2 μ m in the absence of organic template crystallization gel, Nanosized ZSM-5 zeolites seeds were successfully synthesized in the absence of organic template by hydrothermal method firstly, the synthesis and factors such as synthesis mixture composition, ageing and stirring time on affecting the formation of nanosized ZSM-5 zeolite are mainly investigateed The synthesis conditions are optimized and the formation laws of nanosized ZSM-5 zeolite in the absence of organic template by hydrothermal method are discussed. A new method of synthesis free-defect ZSM-5 zeolite membranes by varying-concentration synthesis with organic-free templates sol-gel were adopted firstly. The mechanism of nanosized zeolite formation of membranes was discussed. It was pointed out that pre-coated nanosized seeds and decorated by secondy growth for the formation membrane.