Crystallization Growth of Titanium Silicalite-1 over Monolithic Cordierite Support

Abstract

Titanium silicalite-1(TS-1) membranes were prepared on cordierite support by hydrothermal treatment. The TS-1 membranes were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD) and FT-IR, The factor that the ratio of TPA+/Si on influencing TS-1 crystal was investigated and it was indicated that the ratio of TPA+/Si had a strong effect on its morphology. The TS-1 crystal presented ellipsoid when ratio of TPA+/Si was 0.15. However, the morphology of TS-1 crystal changed to coffin-shaped when the ratio of TPA+/Si increased to 0.4. Each lattice plane of TS-1 crystal grew on cordierite support with different speed which was controlled by concentration of structure-directing agent SDA (TPAOH) in precursor solution. The mechanism of TS-1 crystal growth on cordierite support maybe that the TPA+ in the solution attracts silicate species, titanium species to form inorganic-organic composite species, the aggregation the inorganic-organic composite species formed crystal nucleus, the morphologies changed due to the growth rate of different lattice planes.