掺铂二氧化钛纤维光催化降解氯仿的研究

Study on Photocatalytic Degradation of CHCl_3 over Pt/TiO_2 Fiber Catalyst

TiO2 纤维作为一种微米级光催化剂应用于废水处理时 ,不但克服了TiO2 纳米颗粒不易分离回收的困难 ,而且对其进行贵金属掺杂 ,可使其光催化活性大大提高 .用光还原沉积法制备了掺铂的二氧化钛纤维催化剂 (Pt/TiO2 (F) ) ,并将其作为光催化剂用于光催化降解氯仿反应 ,考察了掺铂量、氧及 pH值等条件对降解氯仿反应的影响 ,并与掺铂的二氧化钛颗催化剂粒 (Pt/TiO2 (G) )的光催化活性进行了比较 .结果表明 ,当掺铂量w(Pt) =0 5 % ,催化剂用量为 0 5g/L ,预先溶氧至饱和状态 ,c0 (CHCl3) =1mmol/L ,pH =5 ,用 30 0W中压汞灯光照 12 0min时 ,Pt/TiO2 (F)上氯仿的降解率可达 98 4 4 % ,而Pt/TiO2(G)上氯仿的降解率仅为 72 0 3% .

Pt doped TiO 2 fiber catalyst (Pt/TiO 2(F)) with different Pt content was prepared using photoreductive deposition method. TiO 2 fiber (2 00 g) was suspended in 200 ml of platinizing solution (aqueous isopropanol solution) with different H 2PtCl 6 content. This suspension was thoroughly flushed with nitrogen to remove oxygen and CO 2 in it. The reaction mixture was irradiated with a 300 W mercury vapor lamp for 3 h. Pt/TiO 2(F) was obtained after filtrating and heating the filter cake at 120 ℃ for 24 h. The Pt/TiO 2(F) samples were characterized by X ray diffraction (XRD), atomic force microscopy (AFM), X ray photoelectron spectroscopy (XPS) and BET method. The photocatalytic degradation of chloroform over Pt/TiO 2(F) was investigated in aqueous suspension irradiated by UV light with the wavelength range of 310～380 nm. The overall degradation rate of CHCl 3 increased drastically when the Pt content increased from 0 1% to 0 5%, and then decreased by further doping. Compared with the native TiO 2 fiber, Pt/TiO 2(F) enhanced notably the photocatalytic activity for degradation of CHCl 3. The effects of Pt content, O 2 and pH on the reaction were investigated. The results showed that the maximum degradation rate of CHCl 3 could reach 98 44% when c 0(CHCl 3)=1 mmol/L , pH=5, ρ (cat) =0 5 g/L , O 2 was pre saturated. Under the same conditions, the degradation rate of CHCl 3 was 72 03% when Pt/TiO 2 granule (Pt/TiO 2(G)) was used.