纳米TiO_2光催化降解DMF

Photocatalytic degradation of DMF over nano-TiO_2

研究了纳米TiO2(P25)光催化降解DMF水溶液,考察了初始浓度、溶液pH值、空气、H2O2、O3对DMF降解率的影响。结果表明:在低浓度范围内,光催化降解DMF遵循L-H方程,表观反应速率常数k=33.3mg/(L.m in),吸附速率常数K=1.84×10-4L/mg,并通过静态吸附实验验证了P25表面对DMF的弱吸附特性,进而得出吸附过程是DMF光催化降解的控制步骤。pH值对DMF降解率影响较大,当pH值由11.0降为4.0时,DMF降解率由51.5%升高到71.0%。空气和H2O2的加入能够加速DMF的光催化降解,O3体系可以显著增强P25对DMF光催化降解效应,其降解率和降解效率分别是空气体系的1.5和2倍左右。

Degradation of DMF aqueous solution was investigated when nano-TiO2 （ P25 ） was used as the photocatalyst. The effect of initial concentration, pH value, air, hydrogen peroxide, ozone on the rate of DMF photocatalytic degradation was studied. The results showed that photocatalytic degradation of DMF follows L - H equation with the apparent reaction rate constant k =33.3 mg/（ L · min） and absorption rate constant K = 1.84 × 10^-4 L/mg at the low concentration. Furthermore, experiments demonstrate the poor adsorption character of DMF on the surface of P25, which is the control step of photocatalytic degradation of DMF. The results of experiments showed that pH value has the considerable influence on the degradation rate of DMF. When pH value varies from 11.0 to 4. 0, photocatalytic degradation rate of DMF increases from 51.5% to 71.0%. Meanwhile, the photocatalytic degradation rate of DMF can be improved by air and hydrogen peroxide. And ozone can improve the photocatalytic degradation rate of DMF. With the intervention of ozone, photocatalytic degradation rate of DMF is almost 1.5 times higher than that of air system.