Preparation Of B-oriented MFI Zeolite Membrane

Zeolite molecular sieve is a highly regular nano-sized channel of aluminosilicate crystalline material,with high thermal stability and corrosion resistance characteristics.MFI-type molecular sieves have a unique pore structure,the vertical axis of the b-axis and the sinusoidal channel of the a-axis.The pore size is about 0.55 nm,with industrial important benzene,toluene,xylene and other organic small molecular dynamics radius similar.Therefore,MFI zeolite zeolite membrane has great potential in chemical sensors,catalytic coating reactors,corrosion-resistant coatings and optical materials.In particular,the b-axis oriented MFI zeolite membrane has become the latest research hotspot in the field of film because of its short diffusion path and small molecular mass transfer resistance.b-axis orientation MFI-type molecular sieve membrane synthesis methods are in situ hydrothermal synthesis,secondary growth method,microwave synthesis method.In situ hydrothermal synthesis of b-axis oriented MFI-type molecular sieve membrane technology is mature and easy to large-scale production,but the carrier and its surface modification requirements are higher.In situ hydrothermal synthesis,the surface of the carrier was modified to enhance the interaction between the molecular sieve and the carrier,and the molecular sieve membrane was induced to grow.a new path was established for the preparation of the b-axis oriented molecular sieve membrane.In this study,the surface of the carrier was modified by chitosan/silica composite coating,and the b-axis oriented molecular sieve membrane was prepared by in-situ hydrothermal synthesis.Mainly completed the following work:(1)In situ hydrothermal method,the surface modification and modification of the carrier by chitosan/silica composite coating,to achieve a dense and uniform height on the surface of stainless steel and glass sheets b-axis oriented MFI zeolite membrane.The effects of chitosan/silica mass ratio,molecular sieve synthesis solution ratio and crystallization time on the orientation MFI zeolite membrane were investigated.The crystal structure and morphology of MFI zeolite membranes were characterized by electron spectroscopy(SEM)and X-ray diffraction(XRD).The results show that the mass ratio of chitosan to silica is 0.15,the ratio of molecular sieve synthesis is 1TPAOH:0.2TEOS:90H2O,and the surface of the glass sheet is continuous and compacted at 170 ? for 6h.On the surface of the glass sheet,a continuous,dense b-axis oriented MFI zeolite membrane was obtained(2)The surface of the chitosan/silica composite solution was modified by spherical glass beads,change the content of chitosan in the composite coating,the concentration of the synthesis solution and the crystallization time.and the dense,continuous b-axis oriented MFI zeolite membrane was prepared by in-situ hydrothermal synthesis.The crystal structure and morphology of MFI zeolite membranes were characterized by electron spectroscopy(SEM)and X-ray diffraction(XRD).The results showed that the mass ratio of chitosan to silica was 0.15,the ratio of molecular sieve synthesis was 1 TPAOH:0.2 TEOS:90H2O,the surface of the spherical glass beads can be prepared with a dense,continuous b-axis oriented MFI zeolite membrane.Compared to stainless steel and glass carrier,spherical glass beads for the carrier can be prepared with higher coverage,better orientation b-axis orientation MFI zeolite membrane,with potential industrial application value.