【作者】 张婷；

【导师】 陈敏；

【作者基本信息】 浙江大学 ， 物理化学， 2011， 硕士

【摘要】 挥发性有机化合物VOCs是大气污染的主要来源之一。在众多处理技术中,催化燃烧法是消除VOCs的最有效方法之一,因其能耗低、处理效率高、设备简单,不易形成NOx二次污染等优点在当前VOCs处理技术中备受关注。其中催化剂是VOCs催化燃烧技术的核心。为了克服传统以堇青石蜂窝为载体的催化剂易破碎、热稳定性差等缺点,本论文采用不锈钢丝网(stainless steel wire mesh,标记为SSWM)为催化剂的载体。且经阳极氧化技术,使其表面自生长一层阳极氧化膜来解决载体比表面积小的问题。基于不锈钢丝网作为载体的优良性能及实验室前期所取得的实验成果,为拓宽不锈钢丝网种类在催化剂载体上的应用,本论文使用型号为304网,0.12mm×80目的不锈钢丝网为载体。基于绿色化学是一种新型的化学理念,研究工作从简化金属材料不锈钢丝网的预处理过程中去表层油脂、去氧化皮、表面活化等工艺入手；系统地探索了阳极氧化过程中膜形成过程；通过改变阳极氧化工艺中电解液的种类,使金属材料表面形成与催化活性组分相匹配、厚度适中、孔洞大小合适的阳极氧化膜,从而制备了低含量、环境友好型0.1%Pd-0.05%Pt/不锈钢丝网催化剂。通过XRD、SEM、XPS.TPR、EDX等实验技术对催化剂进行了表征。实验结果表明,该催化剂完全氧化丙酮、甲苯的温度为240℃、180℃。经300h的甲苯氧化稳定性试验中,转化率一直保持98%以上,表现出了优良的稳定性。在前面优化载体预处理基础上,采用电化学沉积法制备了Cu不锈钢丝网催化剂,考察了不同活性组分负载方法对催化剂的催化活性的影响,研究了不同电沉积电压及时间等制备因素,发现当电沉积时间为15min,电压为3V时制备的Cu/SSWM催化剂表现出优良的催化性能,完全氧化丙酮、甲苯和乙酸乙酯的温度分别为240、220、260℃。通过XRD、SEM、XPS、TPR、EDX等实验技术,表征了不同Cu不锈钢丝网催化剂的物理化学性质,发现不锈钢丝网表面高度分散的CuO物种以及CuO物种与阳极氧化膜的强相互作用,对催化剂的催化活性和稳定性能起到重要作用。更多还原

【Abstract】 VOCs are one of the main sources of air pollution. Among current technologies on VOCs control, catalytic combustion technology has been regarded as the most effective one because of its relatively low energy consumption, high efficiency and simple equipments. Moreover, there is no associated pollution such as nitrogen oxides (NOx) production. And a catalyst with high activity is the key to catalytic combustion of VOCs.In order to conquer the disadvantages of conventional cordierite honeycomb support, such as low thermal stability and easy fragmentation, we applied stainless steel wire mesh (SSWM) as the catalyst support. Moreover, the anodic oxidation treatment was applied to design a porous membrane over the stainless steel wire mesh surface to enlarge the surface area.The stainless steel wire mesh has excellent performance as catalyst support and some excellent experimental results have been obtained in the past. To broaden the stainless steel wire mesh application in catalyst support, we applied the Type 304, 0.12mm×80 mesh as the catalyst support. As green chemistry is a novel chemical concept, the research greatly optimized the process of removal of oil, primary oxides and other superficial impurities of the stainless steel wire mesh; systematically investigated the membrane formation of during the anodic oxidation process; changed the anodic oxidation electrolytes to form the membrane of medium thickness and right size hole. A Low levels and environment-friendly catalyst of 0.1% Pd-0.05% Pt/stainless steel wire mesh catalyst was prepared for VOCs elimination. The morphologies and reducibility of the stainless steel wire mesh supports and catalysts were characterized by means of scanning electron microscopy (SEM), temperature-programmed reduction (TPR), X-ray photoelectron spectrometry (XPS) and Energy-dispersive X-ray spectroscopy (EDX). The results indicated that 0.1%Pd-0.05%Pt/SSWM held better catalytic performance for VOCs. The temperatures of complete acetone and toluene conversion are low to 180 and 240℃, respectively. Moreover, the catalyst shows stable activity under the reaction of toluene oxidation at 200℃for 300 h.On the basis of the pretreatment of catalyst support above, Cu/stainless steel wire mesh catalysts were synthesized via electrochemical deposition. The effect of different active component load methods on the catalysts catalytic activity was investigated; also the electrochemical deposition voltage and time. When the electrochemical deposition voltage and time was 3V and 15min, the catalyst Cu/SSWM exhibit best catalytic activity; The temperatures of complete acetone, toluene and ethyl acetate conversion were 240.220 and 260℃, respectively. The surface structure and reducibility of the stainless steel wire mesh supports and Cu catalysts were characterized by means of SEM, TPR, XRD, XPS arid EDX. The results indicated that high dispersed CuO species on the support surface and the interaction between CuO species and the anodic oxidation membrane play an important role in catalytic activity and stability.更多还原