TiO_2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 TiO2colloid 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 W/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.