气相正己烷的光催化及臭氧/光催化降解动力学

Kinetics of Degradation of Hexane in the Gas Phase by Photocatalysis and Combined Photocatalysis and Ozone

初步研究了气相中低浓度的正己烷在较大流量 (5L/min～ 17L/min)臭氧 /紫外 (O3 /UV) ,光催化 (TiO2 /UV)及臭氧 /光催化 (O3 /TiO2 /UV) 3种方法的降解的动力学 ,考察了正己烷的初始浓度、流量、水蒸气浓度、臭氧投加量等因素的影响 .研究表明 :正己O3 /TiO2 /UV降解效率远高于O3 /UV的降解效率 ,明显高于TiO2 /UV降解效率 ;相对于初始浓度 ,正己烷的TiO2 /UV及O3 /TiO2 /UV反应符合L H模型 ,对于O3 /UV过程用L H模型不能得到较好的拟合 ;随着流量的增加正己烷在TiO2 /UV与O3 /TiO2 /UV降解过程中的反应速率先增加后保持不变 ,但是在O3 /UV过程中其反应速率变化不大 ;湿度对正己烷的降解有一定的影响 ;随着臭氧投加量的增加 ,正己烷O3 /UV和O3 /TiO2 /UV的降解速率呈直线增加 ,在O3 /UV过程中正己烷的反应速率增加更快 .

The degradations of trace hexane under high flow rate (5L/min～17L/min) in the gas phase by TiO 2/UV, O 3/UV and O 3/TiO 2/UV were studied. The kinetic effects of the inlet concentration of hexane, flow rate, water concentration and ozone dosage on the conversion of hexane in the three processes were examined respectively. The experimental results showed that the addition of ozone to the photocatalysis process increased the conversion of hexane significantly. The O 3/TiO 2/UV process was more efficient than the TiO 2/UV in decomposing hexane. The degradation rate increased with increasing the initial concentration of hexane in the processes of TiO 2/UV and O 3/TiO 2/UV. They matched well with the Langmuir-Hinshelwood(L-H) kinetic model. In the range of flow rate studied, the degradation rate increased with an increasing flow rate in both processes of TiO 2/UV and O 3/TiO 2/UV, while was not affected in the process of O 3/UV. The degradation rate in the three processes was affected by water concentration. The degradation rate of the two processes O 3/UV and O 3/TiO 2/UV increased almost linearly with the increase of ozone dosage.