【作者】 李雯婧；

【导师】 全燮；

【作者基本信息】 大连理工大学 ， 环境科学， 2007， 硕士

【摘要】 碳纳米管由于其具有优良的机械强度、化学性能和吸附性能，是一种极具应用前景的环境功能材料。以开发碳纳米管功能材料在环境领域中的应用为目的，本文采用简单易操作的常压化学气相沉积法，以二甲苯作为碳源，二茂铁作为催化剂，氢气／氩气为载气，分别在石墨、钛、镍三种不同的基体上尝试制备碳纳米管电极，采用混酸（HNO₃+H₂SO₄）氧化对碳管进行纯化和修饰。采用扫描电镜和透射电镜对制得的碳管形貌进行表征，表明在钛基体上可以生长出碳纳米管有序阵列，采用FT-IR测试表明纯化修饰后碳管的表面具有磺酸基（-SO₃H），羰基（-C=O），羟基（-OH）等亲水性基团，采用交流阻抗分析不同沉积时间的碳管的电学性质，并且综合考虑机械性能和电极稳定性等因素，确定最佳的化学气相沉积时间为5min。采用直流恒电位沉积催化剂Pd，制备出Pd／MWCNTs／Ti电极。碳纳米管具有优良的储氢能力和电子传导能力。将Pd／MWCNTs／Ti电极应用于加氢还原的反应体系中，对环境中的有机污染物进行降解实验。本文采用H型反应器，考察了Pd／MWCNTs／Ti电极对偶氮染料酸性红B的脱色反应效果和对2，4，5-三氯联苯的还原脱氯效果，同时建立了具有高脂溶性、低水溶性的多氯联苯类物质的电化学还原反应体系。结果表明Pd／MWCNTs／Ti电极对偶氮染料的脱色具有良好的效果，在-0.8V的外加偏压下，120min的脱色率达到77.2％，脱色反应受外加偏压和阳极电解液pH值的影响较大，电极的稳定性良好；Pd／MWCNTs／Ti电极对2，4，5-三氯联苯的还原脱氯尚未获得良好的脱氯效果，在-1.1V的外加偏压下，40h脱氯效率仅有26.5％。由于多氯联苯还原脱氯效果不明显，本文从加强传质的角度出发，提出了反应装置的改进方案。总之，采用气相沉积法制备碳纳米管电极，不但方法简单，成本低，而且碳纳米管电极在环境污染治理领域具有良好的应用价值和深远的应用前景。更多还原

【Abstract】 Carbon Nanotubes（CNTs） are promising functional materials for their strongmechanism intensity, chemical capability and considerable adsorption. In order todevelop their application in environmental field, the multi-walled carbon nanotubes（MWCNTs） on different Ti, Ni, graphite substrates are prepared by chemical vapordeposition （CVD） with dimethylbenzene as carbon source and ferrocene as catalystand then they are purified in the HNO₃+H₂SO₄ solution in this study, respectively.The prepared electrodes are characterized by SEM, transmission electron microscopy（TEM）, and X-ray diffraction （XRD）. The results indicate that carbon nanotubes arewelled arrayed on the Ti substrate and their diameter is about 10nm to 30nm. TheFT-IR spectrum shows that the surface of multi-walled Carbon nanotubes containssome hydrophile groups such as -SO₃H, -C=O and -OH. The electric capability ofdifferent chemical vapor deposition time is detected by A.C impedance. Theconclusion is that the optimal deposition time is 5 min considering the mechanismintensity, stability and electric capability. The Pd is electrochemical deposited on thecarbon nanotubes at the 200 mV potential bias and then the Pd/MWCNTs/Ti electrodeis prepared for further use.It is known that the carbon nanotubes have excellent abilities of storing uphydrogen and electronic conduction. Therefore the Pd/MWCNTs/Ti electrode isapplied in the electrochemical reaction of hydrogenation in the field of environmentalpollution removal. The decolor efficiency of azo dye and the dechlorinationalefficiency of 2,4,5- polychlorinated biphenyl（2,4,5-PCB） are investigated usingH-type reactor with Pd/MWCNTs/Ti electrode as cathode. The results suggest that theapplication of Pd/MWCNTs/Ti in decoloring azo dye can achieve approving effectwith the decolor efficiency 77.2％at -0.8V voltage during 120 min electrochemicalreaction. The decolor efficiency is strongly influenced by the potential bias and the pHvalue of anodic electrolyte meanwhile the Pd/MWCNTs/Ti electrode is provided withgood stability in the reaction. On the other hand, the dechlorination of 2,4,5-PCB hasnot achieve satisfactory effect with its dechlorinational efficiency only 26.5％at -1.1V potential bias during 40 hours electrochemical reaction. Also, at the point ofenhancing transmission ability, an improved scheme is proposed in this study.In conclusion, chemical vapor deposition is an easily-operated and economicalprocess for synthesis multi-walled carbon nanotubes （MWCNTs）. Furthermore, themulti-walled carbon nanotubes electrode has outstanding application value andpromising prospect in environmental field.更多还原