摘要
以钛酸四丁酯为前驱体,冰醋酸为水解抑制剂,采用溶胶-凝胶法制备纳米TiO2/CNTs复合催化剂。测定复合催化剂对不同浓度茜素红溶液的光降解活性,并对光催化降解动力学进行研究。结果表明,在CNTs负载质量分数7.5%、焙烧温度450℃和焙烧时间3.5 h条件下制备的TiO2/CNTs复合催化剂光催化活性得到提升。相同条件下,TiO2/CNTs对150 mg·L-1茜素红溶液的最终降解率达67%,而TiO2的最终降解率只有56%。复合催化剂光催化活性提升的原因是CNTs负载后光催化粒子在紫外光照射下生成更多的氢氧根活性自由基。光催化降解动力学符合Langmuir-Hinshelwood方程,催化剂对污染物的表观吸附是整个反应的"瓶颈"。随着反应浓度的增大,光催化降解反应的反应级数由一级反应逐渐下降为零级反应。
Using tetrabutyl titanate as the precursor and acetic acid as the depressor,TiO2/CNTs composite catalyst was prepared by sol-gel method. The photo-degradation activity of TiO2/CNTs composite catalyst for photocatalytic degradation of alizarin red solution with different concentrations was investigated,and its photocatalytic degradation kinetics was also studied. The results showed that the optimal preparation condition of composite catalyst was as follows：CNTs loading mass fraction 7 . 5%,calcination temperature 450 ℃and calcination time 3. 5 h,and the photocatalytic activity of TiO2/CNTs composite catalyst was improved. Under the same condition,the final degradation rate of alizarin red solution with the concentration of 150 mg·L-1 over TiO2/CNTs catalyst reached 67%,while the final degradation rate of alizarin red solu-tion over TiO2 only was 56%. The reason for photocatalytic activity improvement of composite catalyst was that it could generate more active hydroxyl under UV irradiation when TiO2 was loaded on CNTs. The photocatalytic degradation kinetics of the composite catalyst complied Langmuir-Hinshelwood equation. The catalyst surface adsorption to pollutants was the bottleneck of reaction,and the reaction order of kinetics decreased from one order to zero level with the increase of pollutant concentrations.
出处
《工业催化》
CAS
2014年第11期836-840,共5页
Industrial Catalysis
基金
广东省教育厅育苗工程项目(2013LYM0058)
茂名市科技计划(201312)资助项目
关键词
催化剂工程
溶胶-凝胶法
茜素红
光催化降解
动力学
TiO2/CNTs
catalyst engineering
TiO2/CNTs
sol-gel method
alizarin red
photocatalytic degradation
kinetics
