不同金属氧化物对等离子体降解甲苯的作用研究  

Effect of different metal oxides on the plasma decomposition of toluene

作　　者：廖晓斌[1] 郭玉芳[2] 叶代启[1] 

机构地区：[1]华南理工大学环境科学与工程学院,广州510006 [2]广州大学环境科学与工程学院,广州510006

出　　处：《环境科学学报》2010年第9期1824-1832,共9页Acta Scientiae Circumstantiae

基　　金：高等学校博士学科点专项科研基金资助课题(No.20070561042);国家高技术研究发展计划(863)(No.2006AA06A310);国家自然科学基金(No.50978103;50708021);华南理工大学"污染控制与生态修复"广东省高等学校重点实验室开放基金项目~~

摘　　要：常温常压下,研究介质阻挡放电(DBD)与4种金属氧化物催化剂(FeOx、MnOx、CuO、CoOx)联用降解甲苯废气.比较不同催化剂对甲苯去除率(η)、COx选择性(Scox)、副产物(O3、NO、NO2)产生量及能量产率(ηY)的影响.同时,用BET、XPS、H2-TPR、FT-IR等方法对催化剂进行表征,探究各种催化剂的不同作用.研究发现,FeOx的甲苯去除率及能量产率最高,而MnOx在分解O3和提高COx选择性方面效果最显著,但生成的NOx略高于其它催化剂.BET和H2-TPR的结果解释了4种催化剂的活性顺序:FeOx>MnOx>CuO>CoOx>无催化剂.XPS结果表明,使用过的锰催化剂有不同价态的C、N、O元素,且含有C—N,CO,C—O,CN或O—H键.FT-IR的结果进一步证实了这些键的存在,且发现可能有甲苯及其中间产物、苯甲醇和苯甲酰胺或其它酰胺物种存在,这可部分解释催化剂减少副产物生成量的原因.同时提出等离子体场下甲苯氧化机理.The performance of toluene removal with four kinds of metal oxides catalysts,i.e.,iron oxide,manganese oxide,copper oxide and cobalt oxide,was studied in a dielectric barrier discharge（DBD） system at room temperature and atmospheric pressure.Effects of metal oxide catalysts on toluene removal efficiency（η）,carbon oxide selectivity（Scox）,energy yield（ηY） and amounts of byproducts such as O3 、NO、NO2 were compared.In order to investigate the performance of the catalysts,they were characterized by BET,XPS,H2-TPR and FT-IR.The highest toluene removal efficiency and energy yield were achieved with the iron oxide catalyst.Manganese oxide showed a remarkable ability to reduce the formation of O3 and increase the selectivity of the carbon oxides,but the amount of NOx produced was a little more than with the other catalysts.The results of BET and H2-TPR showed the sequence of catalytic activities for the four catalysts to be： FeOx MnOx CuO CoOx no catalysts.XPS showed that C,N and O with different valences as well as the C—N,C O,C—O,C N and O—H bonds existed on the surface of the manganese oxide catalyst after plasma reaction.These bonds were also verified by FT-IR.The FT-IR results also suggested that toluene and its intermediates,benzyl alcohol as well as benzene formamide or other amides,probably exist in the reaction.And this could partly explain the reduction of byproducts with the use of catalysts in the plasma system.Finally,a mechanism of toluene oxidation in a plasma system is proposed.

关 键 词：介质阻挡放电 甲苯氧化 催化剂 副产物 自由基 

分 类 号：X131.1[环境科学与工程—环境科学]