Pt/TiO_2膜光催化氧化降解高聚物的研究

PHOTOCATALYTIC DEGRADATION OF POLYVINYL ALCOHOL (PVA) USING Pt/TiO_2 MEMBRANE

以 2 5 0W高压汞灯为光源 ,通过光化学沉积法在TiO2 表面上担载 1%Pt制备的催化剂对难降解高聚物PVA具有很好的光催化活性 ,固定相活性提高后的该类催化剂在用量为 30g/m2 时 ,光照 6 0min ,PVA的光解率可达78 3%。研究发现 ,PVA的光催化氧化可分为两个阶段 ,前一阶段PVA主要生成中间产物 ,后一阶段 ,PVA被彻底氧化分解 ,1%Pt/TiO2 可以明显地缩短前阶段反应时间 ,增强后阶段PVA的矿化作用 ,增加矿化阶段反应级数与反应速度常数。

Immoblized photocatalytic oxidation of PVA was investigated in an open fixed-bed photoreactor illuminated with 250 W high pressure mercury lamp and using supported catalyst of Pt/TiO2 and TiO2. The results showed that the catalyst of TiO2 which was with 1% Pt by photochemical process had the most efficient photoactivity. When 30 g/m2 TiO2 were fixed on the bottom of the plane photoreactor, the removal rate of PVA reached 78.3% after 60-minuite illumination. It was also found that the degradation of PVA could be divided into 2 parts. In the first part, no TOC was degraded, while in the second part, the removal rate of TOC could be described by dc/dt=kcn equation. The first reaction part of the photocatalytic oxidation of PVA was decreased using Pt/TiO2. Furthermore, the reaction series was increased while the reaction velocity coefficient was almost not changed.