MWNTs/TiO2光催化降解氧乐果农药影响因素及动力学研究
Kinetics and Factors Influencing Photocatalytic Degradation of Omethoate by MWNTs/TiO2
投稿时间:2017-03-14  修订日期:2017-06-22
中文关键词:多壁碳纳米管  复合光催化剂  氧乐果  反应动力学
英文关键词:multi walled carbon nanotubes  composite photocatalyst  omethoate  reaction kinetics
基金项目:湖南省自然科学基金项目(2015JJ2022);湖南省教育厅科学研究重点项目(11A022);湖南省教育厅科学研究一般项目(15C0260);湖南省产学研合作示范基地建设项目;2016年度高校科技成果产业化培育项目(15CY002).
作者单位E-mail
张 伟 湖南城市学院市政与测绘工程学院湖南 益阳 413000 沈阳建筑大学市政与环境工程学院辽宁 沈阳 110168 hnweizhang@163.com 
王 珏 湖南城市学院市政与测绘工程学院湖南 益阳 413000 沈阳建筑大学市政与环境工程学院辽宁 沈阳 110168 hnwaihe409@163.com 
汪爱河 湖南城市学院市政与测绘工程学院湖南 益阳 413000  
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中文摘要:
      通过合成多壁碳纳米管/二氧化钛(MWNTs/TiO2)复合光催化剂,研究其对氧乐果农药的降解效率和作用机理,为去除水体中农药提供高效环保的水处理技术。通过溶胶-凝胶法制备多MWNTs/TiO2复合光催化剂,其中钛酸丁酯:异丙醇:水摩尔比为1:25:3、MWNTSs为0.5g、MWNTSs与TiO2质量比为100:1.5。采用批实验法考察了复合材料投加量(200、400、600、800、1000mg/L)、溶液pH值(3、5、7、9、11)、氧乐果初始浓度(20、75、150 mg/L)、温度(15, 25, 35℃)、光照强度(385、560W)等因素对其降解效果的影响,对比了MWNTs/TiO2和TiO2两种催化剂对降解效果。并通过SEM和EDS等手段对MWNTs/TiO2复合光催化剂进行表征。结果表明,TiO2均匀覆盖在MWNTs上,其中TiO2占复合光催化剂的质量分数为59.59%;MWNTs/TiO2复合光催化剂对氧乐果的降解效率受复合材料投加量、溶液pH值、氧乐果初始浓度、温度、光照强度等因素影响较大,在氧乐果初始浓度75mg/L、MWNTs/TiO2投加量600 mg/L、pH值为3、温度35℃及光照强度560W最佳条件下,MWNTs/TiO2对氧乐果的光催化降解率为60.71%。降解动力学分析发现降解过程符合一级反应动力学方程,降解速率常数为0.0033h-1。在同样的条件下,MWNTs/TiO2复合光催化剂比TiO2降解效率提高了8.45%。
英文摘要:
      Previous study has shown that the multi-walled carbon nanotubes/titanium dioxide(MWNTs/TiO2) composite photocatalyst has higher adsorption and photocatalytic activity than TiO2 alone. In this study, omethoate, a highly toxic organophosphorus pesticide, was selected as the degradation target and the degradation efficiency and mechanism of MWNTs/TiO2 were studied. The effects of initial pH, dosage, temperature, light intensity and initial concentration of omethoate on the degradation efficiency of MWNTs/TiO2were investigated. The study provides basic data to assess the potential of an efficient and environmentally friendly technology for the removal of pesticides from water. MWNTs/TiO2 were prepared using the sol-gel method, using tetrabutyltitanate, isopropyl alcohol and water in the molar ratio of 1:25:3 and MWNTSs(0.5 g), MWNTSs:TiO2 at a mass ratio of 100:1.5. Batch experiments were carried out under different conditions by varying the following factors: initial pH (3, 5, 7, 9, 11), photocatalyst dosage (200, 400, 600, 800, 1000mg/L), temperature (15, 25, 35oC), light intensity (385, 560 W) and initial omethoate concentration (20, 75, 150 mg/L). MWNTs/TiO2 was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy(EDS). TiO2 evenly covered the surface of the MWNTs and the mass of TiO2 accounted for 59.59% of the composite photocatalyst. The removal efficiency of omethoate was markedly affected by MWNTs/TiO2 dosage, pH, initial omethoate concentration, temperature and light intensity. The degradation efficiency of omethoate pesticide was 60.71 % when the system operated under optimal conditions (initial pH, 3;MWNTs/TiO2 dosage, 600 mg/L; temperature, 35℃; light intensity, 560 W and initial omethoate concentration, 75 mg/L).The reaction kinetics data well fitted first order kinetics and the rate constant (k) was 0.0033 h-1. Under the same reaction conditions, the degradation efficiency of MWNTs/TiO2 was 8.45% higher than TiO2. This study indicates that the photocatalytic degradation of omethoate in waste water could be effectively achieved by using the MWNTs/TiO2 photocatalyst.
张 伟,王 珏,汪爱河.2017.MWNTs/TiO2光催化降解氧乐果农药影响因素及动力学研究[J].水生态学杂志,38(6):27-33.
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