Synthesis And Application Of TS-1 Zeolite

TS-1 zeolite is a type of catalyst with MFI topology.Its structure is composed of silica tetrahedron and titanyl tetrahedron.The successful synthesis of titanium-silicon molecular sieve TS-1 extends the application of molecular sieve from acid catalysis to selective oxidation.TS-1 not only has unique type selection characteristics,its TS-1/H₂O₂ oxidation system shows excellent catalytic performance in the selective oxidation of a variety of organic substances,and the reaction conditions of this reaction system are mild,and the final oxidation product is water,which The concept of green development has received extensive attention from researchers.In this paper,stirring is introduced into the traditional zeolite synthesis method to investigate the synthesis law of TS-1 zeolite.Change the crystallization time,the ratio of silicon to titanium,the amount of template agent,and study the effect of different synthesis conditions on the physical and chemical properties of the synthesized molecular sieve.A self-made seed crystal is also added to assist in the synthesis of TS-1.The prepared TS-1 zeolite was characterized by SEM,XRD,FT-IR,UV-vis,XPS,N₂ adsorption technology.Finally,the synthetic TS-1 zeolite was applied to a system using thiophene n-octane as a simulated oil,and the catalytic oxidation desulfurization performance of TS-1 zeolite was investigated,and the following conclusions were obtained:Using dynamic kettle to synthesize TS-1,the shortest time is only 1h to obtain TS-1 zeolite with MFI structure.The synthesized TS-1 zeolite has a particle size of about 600nm and contains a large number of micropore structures.With the extension of crystallization time,anatase Ti O₂ appeared in the samples.In the catalytic oxidation desulfurization reaction,the sample with the shortest crystallization time TS-1-1h has the best catalytic effect,and the final removal rate of thiophene reaches 86.6%.The catalytic performance decreases with increasing sample crystallization time.The TS-1 zeolite can be successfully synthesized by changing the ratio of silicon-titanium in the initial synthesis liquid within the range of 20-80.The different ratio of silicon to titanium has a significant effect on the morphology and pore structure of the TS-1 samples.The higher the amount of titanium source in the initial synthesis solution,the higher the titanium content of the TS-1 molecular sieve framework synthesized.The sample prepared with Si/Ti=30 has the best catalytic oxidation performance.TS-1 zeolite can be successfully synthesized when the template agent molar ratio is 0.2,0.3,0.4 and 0.5.Changing the amount of template agent has a great influence on the properties of TS-1 zeolite.The TS-1 zeolite sample has the highest crystallization degree when the template agent molar ratio is 0.3.The specific surface area of the sample with a template agent molar ratio of 0.4 is as high as 590.7 m²/g.When the molar ratio of the template agent is 0.2,the crystallization degree of the molecular sieve is not complete.When the molar ratio of the template agent is 0.5,the excessively high alkaline environment will affect the morphology of the zeolite.At this time,the conversion rate of thiophene in the catalytic oxidative desulfurization of zeolite is up to 84%.Compared with the sample without seeding,the zeolite appearance of the sample with seeding has undergone two changes,some grains become smaller in size,and a small number of grains form a huge hexagonal plate-like structure.The statically synthesized 4 groups of samples formed more mesopores of 35-50nm,and the addition of seed crystals contributed to the formation of mesoporous structures.The catalytic oxidation performance of t TS-1-4h with added seed crystals was significantly improved,and the thiophene removal rate was as high as 93%.