Abstract: Nano-TiO₂/SiO₂ was used as catalyst to investigate the influence of different calcined temperatures on the photocatalytic activity of the catalyst for the photocatalytic degradation of heptene. The photocatalytic activity of the catalyst is the highest when the calcination temperature is 600 ℃. The photocatalytic degradation rate of heptene increased with increasing the initial concentration of sulfur dioxide, but maintained almost a constant beyond a certain concentration. When the concentration of sulfur dioxide was fixed, the reaction rate increased separately with increasing oxygen content and water vapor content, when oxygen content was 20%, the reaction rate was the highest, while water vapor content was 444 μmol/L, there was an optimum value for the photocatalytic degradation rate of heptene. The degradation rate of heptene increased with light intensity but the rate approached to level off when the light intensity rose to 8.32 mW/cm². The reaction products were identified by FT-IR and GC-MS.

Key words: heptene, sulfur dioxide, photocatalytic, TiO₂/SiO₂