Abstract
The dosages of colloidal silicon seeds in the seed-induced synthesis of TS-1 zeolites were investigated in detail. The characterization results revealed that the colloidal silicon seeds not only reduced the particle sizes but also promoted the incorporation of titanium atoms into the framework of TS-1 zeolites as prepared. SEM images and particle size distribution (PSD) confirmed that the particle sizes of TS-1 zeolite could be effectively reduced to about 150 nm. The lattice plane [2 1 0] and [0 2 0] of 7.0-Seed-TS-1 zeolite were well exposed, as observed by the HRTEM images. It is worth noting that the ratio of non-framework Ti atoms incorporated onto the surface of TS-1 zeolites increased slightly to 0.11% by XPS. By regulating the dosage of colloidal Si seeds and promoting rapid nucleation, the size of the crystals could be easily tuned, and then the resulting high external specific surface area and pore volume ensured the reactant accessibility to the active site. The TS-1 zeolites regulated by the 5.0~7.0% dosages of colloidal silicon seeds possessed high external specific surface areas (148.1 m(2)/g and 130.9 m(2)/g) and small particle sizes (about 150 nm). The oxidative desulfurization of 500 ppm DBT by 7.0-Seed-TS-1 zeolite could reach to 100%.