Treatment of Volatile Organic Compounds using Catalyst Assisted Silent Discharge

利用大气压无声放电对挥发性有机物进行了处理。将催化剂置于电极上，考察了等离子体与催化剂之间的相互作用对分解的影响。甲醇和苯被用作VOCs的模型。在无催化剂的情况下，甲醇和苯的转化率均随电压和气体停留时间的增加而增加。分解速率常数与放电功率有关，放电功率受外加电压和电极间隙的影响。这里使用的催化剂是由氧化铝负载的Pt负载催化剂。在没有等离子体的情况下没有观察到催化分解。而在放电条件下，催化剂对分解有促进作用.在较低的苯浓度下观察到较高的增强。没有明显观察到Pt负载量的影响。主要产物气体为二氧化碳和一氧化碳。通过GC-MS检测到痕量苯酚，但未观察到其他有毒物质。放电产生大量的臭氧。然而，臭氧被认为不会影响分解。在苯的分解反应中，由于催化剂上沉积了黄色固体物，导致催化剂失活。Pt负载量越小，失活进行得越快。还研究了钒氧化物作为催化剂。结果还表明，苯的分解的增强而不失活的催化剂。研究结果表明，在不消耗大量电能的情况下，利用催化剂进行无声放电是控制低浓度VOCs的有效方法。

The treatment of volatile organic compounds (VOCs) was carried out using atmospheric silent discharge. The catalyst was put on the electrode and the effect of the interaction between plasma and catalyst on the decomposition was examined. Methanol and benzene was used as a model of VOCs. The conversions of both methanol and benzene were increased with applied voltage and gas residence time without catalyst. The decomposition rate constant was related with discharge power affected by both applied voltage and electrode gap. The catalyst used here was Pt loading catalyst supported by alumina. The catalytic decomposition was not observed without plasma. However the decomposition was promoted by the catalyst under the discharge condition. Higher enhancement was observed at lower concentration of benzene. The effect of the amount of Pt loading was not apparently observed. The main product gases were carbon dioxide and carbon monoxide. The trace of phenol was detected by GC-MS, however the other toxic substances were not observed. Much amount of ozone was produced by the discharge. The ozone, however, is not considered to affect the decomposition. The deactivation of the catalyst was observed in the benzene decomposition because of the formation of yellow solid materials deposited on the catalyst. The deactivation proceeded faster for smaller Pt loading catalyst. The vanadium oxide was also investigated as the catalyst. The results also showed the enhancement of the decomposition of benzene without the deactivation of the catalyst. The research summarized that the silent discharge with the catalyst was effective method for the control of VOCs in low concentration without much power consumption.