氮掺杂TiO_2光催化降解甲基橙染料废水的试验研究

Photocatalytic Degradation of Methyl Orange Wastewater with Nitrogen-doped TiO_2

采用溶胶-凝胶法以尿素为氮源制备了氮掺杂锐钛矿型纳米TiO2光催化剂(TEM像图显示制备的样品的平均粒径在20 nm左右,UV-vis漫反射分析表明氮掺杂使催化剂的吸收带边红移至550 nm的可见光区域),以氙灯为辐照光源,用自制光催化反应器降解甲基橙染料溶液,研究了催化剂用量、染料初始浓度和环境pH值变化对甲基橙降解率的影响,同时考察了催化剂在太阳光下的光催化活性,结果表明:当催化剂用量为2 g/L、溶液pH值为2.74时,初始浓度为10 mg/L的甲基橙在氙灯光照45 min后降解率达100%;自然光照120 min后降解率为95.4%。

The N-doped TiO2 photoeatalysts were prepared by the sol-gel method with urea as the nitrogen source. The TEM analysis shows that the average grain size of N/TiO2 is about 20nm. The UV--vis diffuse reflectance spectrum indicates that the absorption edge of N/TiO2 shifts to 550 nm. The degradation of methyl orange （MO） was investigated in a self-made photoreaetor with Xenon lamp as the irradiation source. The effect of the initial concentration of MO,catalyst dosage and pH value on MO degradation was studied. The catalytic activities of photoeatalysts under sunlight irradiation were also investigated. In the condition of TiO2 dosage of 2g/L and pH of 2.74, the MO aqueous solution with initial concentration of 10 mg/L reaches a degradation efficiency of 100 %, with Xenon-light irradiation for 45 minutes. The degradation efficiency of sunlight irradiation is 95.4 G for 120 minutes.