Wang Hui, Wang Hui-Long, Jiang Wen-Feng
Department of Chemistry, Dalian University of Technology, Dalian, Liaoning Province 116023, China.
Chemosphere. 2009 May;75(8):1105-11. doi: 10.1016/j.chemosphere.2009.01.014. Epub 2009 Feb 7.
Multi-walled carbon nanotubes (MWCNTs)-TiO(2) composite photocatalysts with excellent activity were prepared by sol-gel method in order to investigate its photocatalytic activity under solar irradiation for the degradation of 2,6-dinitro-p-cresol (DNPC) in aqueous solution. The prepared composite were analyzed by XRD, FTIR, SEM, TEM, TG-DTA and UV-vis absorption spectra techniques. The results showed that the composite can cause an obvious red shift of UV-vis spectra compared with pure TiO(2). The degradation of DNPC by MWCNTs-TiO(2) composite photocatalysts under solar irradiation was systematically studied by varying the experimental parameters such as pH value, irradiation time, the initial substrate concentration, reaction temperature, catalyst concentration, etc. The optimal conditions were a DNPC concentration of 33.4 mgL(-1) at pH 6.0 with MWCNTs-TiO(2) concentration of 6.0gL(-1) under solar irradiation for the illumination of 150 min. The presence of MWCNTs can enhance the photoefficiency of TiO(2). The highest efficiency on photodegradation of DNPC can be achieved with an optimal MWCNTs/TiO(2) mass ratio of 0.05%. The photocatalytic degradation of DNPC obeys a pseudo-first-order behavior according to the Langmuir-Hinshelwood model, and possible decomposing mechanisms are also discussed. The photocatalyst was used for five cycles with photocatalytic degradation efficiency still higher than 96%. The results of the study showed the feasible and potential use of MWCNTs-TiO(2) composite in degradation of toxic organic pollutants.
采用溶胶 - 凝胶法制备了具有优异活性的多壁碳纳米管（MWCNTs）-TiO₂复合光催化剂，以研究其在太阳光照射下对水溶液中2,6 - 二硝基对甲酚（DNPC）的光催化降解活性。通过XRD、FTIR、SEM、TEM、TG - DTA和紫外 - 可见吸收光谱技术对制备的复合材料进行了分析。结果表明，与纯TiO₂相比，该复合材料能使紫外 - 可见光谱发生明显的红移。通过改变pH值、照射时间、初始底物浓度、反应温度、催化剂浓度等实验参数，系统研究了MWCNTs - TiO₂复合光催化剂在太阳光照射下对DNPC的降解情况。最佳条件为：在pH 6.0时，DNPC浓度为33.4 mgL⁻¹，MWCNTs - TiO₂浓度为6.0gL⁻¹，在太阳光照射下照射150 min。MWCNTs的存在可以提高TiO₂的光效率。当MWCNTs/TiO₂质量比为0.05%时，对DNPC的光降解效率最高。根据朗缪尔 - 欣谢尔伍德模型，DNPC的光催化降解符合准一级反应行为，并讨论了可能的分解机理。该光催化剂循环使用了5次，光催化降解效率仍高于96%。研究结果表明MWCNTs - TiO₂复合材料在降解有毒有机污染物方面具有可行性和潜在应用价值。
