Study on Crystallization Kinetics for Synthesis of TS-1 Zeolite and Its Catalytic Performance

The titanium silicalite-1 (TS-1) zeolite was quickly synthesized through modifying the conventional hydrothermal synthesis procedure with self-made aqueous tetrapropyl ammonium hydroxide as a template. The crystallization kinetics for synthesis of TS-1 zeolite was also investigated. The results show that the induction periods of the crystallization process are all short, and as the crystallization temperature increases, the nucleation rate and crystal growth rate increase. The calculated apparent activation energy of nucleation and crystal growth is 33.60 and 36.73 kJ/mol, respectively, which is a little less than that of conventional hydrothermal synthesis. The pH value of crystalline TS-1 changes more distinctly at the higher crystallization temperature. The formation process of TS-1 zeolite structure is consistent with the process of pH value increase in the synthetic system. The catalytic activity of TS-1 zeolite synthesized at higher crystallization temperature is higher than that synthesized at lower temperature, which is probably attributed to different amounts of framework Ti(Ⅳ) ions, as well as different relative crystallinity of TS-1 zeolite. The crystal size of TS-1 zeolite synthesized at different temperatures varies slightly, but it is approximately 100 nm after all.