Photocatalytic Degradation of Triazophos in Oolong Tea by TiO₂

In order to study the effect of supported TiO₂ on the ultraviolet photocatalytic degradation of triazophos in oolong tea,the photocatalytic degradation of triazophos was carried out by using supported TiO₂ in a self-made photocatalytic reactor. The effects of calcination temperature,concentration of TiO₂ and the ratio of TiO₂ to PVPK30 on the degradation of triazophos were investigated,and the degradation pathway of triazophos was explored. X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)were used to analyze the characterization of TiO₂. The results showed that the photocatalytic degradation of triazophos accorded with the first-order kinetic equation.The optimum preparation parameters were calcination temperature 500 ℃,TiO₂ concentration 0.15%,content ratio of titanium dioxide to PVPK30 1:1 (m/m),reaction time 10 min.Under these conditions,more than 98% of triazophos residues could be degraded within 10 min.GC-MS analysis showed that the P-O ester bond of triazophos was broken by photocatalytic degradation reaction.XRD and XPS analysis showed that calcination could affect the particle size and crystal form of TiO₂. The mass fraction of anatase decreased with the increase of temperature. The content of TiO₂ hydroxyl oxygen and Ti³⁺ were both at high level at 500 ℃.