新型两级介质阻挡放电降解甲基橙的机理研究

Degradation mechanism of methyl orange by a novel two-level dielectric barrier discharge plasma reactor

采用新型两级介质阻挡放电(DBD)等离子体反应器对甲基橙废水进行降解处理,考察了甲基橙的p H值、电导率、降解率、化学需氧量(COD)随停留时间的变化。采用紫外光谱、红外光谱、液质联用对处理前后的甲基橙废水进行检测,并推测甲基橙降解机理。结果表明:甲基橙废水的p H值随着停留时间的增长而减小,电导率和降解率均随停留时间的增长而增大,甲基橙的COD值随停留时间的增长呈现先减小再升高最后降低趋于平稳的规律;经过表征分析,处理160 min后的甲基橙降废水中含有NO_3^-,HOOCCH_2CH_2CH_2CH_2CH_2SO_3^-,(CH_3)_2NCH_2CH_2CH_2CH_2CH_2COOH等。

The novel two-level dielectric barrier discharge （DBD）plasma reactor was designed for the methyl orange wastewater degradation. The changes of pH, conductivity, degradation rate, chemical oxygen demand （ COD ） of methyl orange with the residence time were investigated. The UV spectra and infrared spectra LC-MS were used qualitatively and quantitatively to detect the degradation products, so that the degradation mechanism of methyl orange can be speculated. The results show that the pH of methyl orange wastewater decreases with the increasing residence time, while the electrical conductivity and degradation rate increases with the increasing residence time; the COD of methyl orange fluctuates with a decrease-increase-decrease trend, and then levels off as resistance time extends; the analysis indicates that the degradation products of methyl orange after 160 min may be NO3^-, HOOCCH2CH2CH2CH2CH2SO3^- , （ CH3 ） 2NCH2CH2CH2CH2CH2COOH.