Study Of Synthesis, Characterization And Property Of Zeolite ZSM-35 Composite Membranes

Zeolite membranes with similar molecular-sized channel systems have potential applications in separation of different substances at molecular levels under the circumstances of high-temperature, chemical and biological corrosions and in integration of catalysis and separation processes. ZSM-35 (FER-type) zeolite possessing unique channel systems has been used as catalysts with good conversion and selectivity and recently found excellent performance in separation of benzene/p-xylene, n-butane/i-butane and water/organic acids. So it is of siginificance to conduct preparation and application studies of ZSM-35 zeolite membranes to obtain excellent-quality ZSM-35 zeolite membranes. In this dissertation, by different synthesis methods, a synthesis of ZSM-35 zeolite membranes was studied in detail respectively adopting different initial synthesis materials respectively on ceramic, stainless steel and carbon supports with different physico-chemical characteristics and ZSM-35 zeolite membrane reactors were assembled to be used in dehydrogenation of ethylbenzene to styrene to examine the as-synthesized zeolite membrane performances.Respectively using pyrrolidine, 1-butylamine and ethylenediamine as templates and different silicon resources, zeolite ZSM-35 membranes have hydrothermally been synthesized in situ respectively on the surfaces of porous ceramic, stainless-steel and carbon supports for the first time. Zeolite crystals grow continuously and compactly on the surfaces of synthesized membranes with no apparent defects. The experimental results achieved are as follows:(1) the orientation of crystals on the synthsized membranes tends to become gradually strong with crystal plane (h00) parallel to the support surface with the calcination temperatures increasing;(2) different templates and different silicon resources all have apparent influences on the morphology or the orientation of the synthesized membranes, among which the crystal growth on the membrane surfaces presents the orientation with crystal plane (h00) parallel to the support surface when ethylenediamine is used as templates;(3) the crystal growth, to some degree, takes on the orientation with crystal plane (h00) parallel to the support surface when the zeolite membrane is grown on the SiO₂ medium layer between the zeolite layer and the support, and H₂ permeation rates of the membrane grown on the SiO₂layer are (3.50-3.85)×10^-7mol·m^-2·s^-1·Pa^-1 with the ideal separation factors of H₂/ C₃H₈ and H₂/ N₂ being 6.89-7.62 and 4.00—4.44, respectively;(4) the zeolite ZSM-35 membrane has been synthesized by directly converting the gel...