TiO2胶体光催化降解罗丹明B染料

TiO2胶体从钛氧有机物水解制备,表征的方法有:X射线衍射光谱(XRD)、激光散射粒径分布、傅立叶变换红外光谱(FT-IR)、X射线光电子谱(XPS)和透射电子显微镜(TEM)。利用罗丹明B染料分子作为探针分子研究TiO2胶体的光催化活性,分析了pH、催化剂用量、外加氧化剂(H2O2)用量及罗丹明B初始浓度对TiO2胶体光催化活性的影响。结果表明:制备的TiO2胶体粒子平均粒径为13.8 nm(激光散法测定),光催化降解罗丹明B染料的反应属于一级动力学反应,可以用Langmuir-Hinshewood模型加以描述,反应速率常数k1为0.08413 mg/(L.min),平衡吸附常数k2为1.5305 L/mg;在pH为6,TiO2胶体用量为0.04%,H2O2(含量30%)用量为0.2%(V/V),光照度为69.6μW/cm2时,5 h后罗丹明B染料的降解率可达到99%以上;相似的条件,0.2%的P25 TiO2粉体光催化处理染料水时,罗丹明B的降解率为90%。纳米TiO2胶体不仅可以提高罗丹明B的光催化降解率,还具有用量少,可有效降低水处理成本的特点。

Photocatalytic degradation of dye rhodamine B by nanosized TiO2 colloids

Nanosized TiO2 colloid was prepared with titanyl organic compound as precursor,and then was characterized by X-ray diffraction(XRD),particle size distribution,fourier transform infrared spectrometry(FT-IR),X-ray photo electron spectroscopy(XPS) and transmission electron microscopy(TEM).The effects of pH,TiO2 dosage,H2O2 dosage and initial content of rhodamine B on the photocatalytic activity of TiO2 colloid were investigated.The results indicated that the mean size of the as-prepared TiO2 colloid was 13.8 nm.When the pH was 6,dosage of TiO2 colloid was 0.04 %,and dosage of H2O2(content 30%) was 0.2%(V/V),the photocatalytic activity of nanosized TiO2 colloid was the best,and more than 99% of the dye rhodamine B was degraded after illumination(69.6 μW/cm2) for 5 hours.Comparing to the fact that about 90% of rhodamine B was degraded when 2.0% of P25 TiO2 was applied,the photocatalytic activity of nanosized TiO2 colloid was much better than P25 TiO2.And a detailed Langmuir-Hinshelwood kinetic model was also applied to explain the photodegradation process.The photodegradation reaction is first-order kinetic reaction,the photodegradation rate constant is 0.08413 mg/(L·min),and the adsorption equilibrium constant is 1.5305 L/mg.