介质阻挡放电处理水中3,4-二氯苯胺机理研究

采用介质阻挡放电产生低温等离子体来处理水中3,4-二氯苯胺(3,4-DCA),考察了放电功率、空气流量、金属离子(Fe2+、Cu2+)浓度、光催化剂二氧化钛对3,4-DCA去除率的影响,并分析了降解产物及可能的降解机理.实验结果表明,介质阻挡放电方法对3,4-DCA有良好的去除效果,在3,4-DCA初始浓度为30mg·L-1,放电功率为80W,空气流量为1L·min-1时,放电处理6min后3,4-DCA的去除率可达92.5%.增加空气流量能显著地提高3,4-DCA的去除率,添加亚铁离子(Fe2+)浓度和光催化剂TiO2均能提高3,4-DCA的去除率,且存在最佳添加量值.介质阻挡放电方法对3,4-DCA的降解去除反应符合一级反应动力学.通过气质联用仪(GC-MS)分析检测发现,反应主要为脱氯、脱氨基和苯环开环反应,二氯乙烯为其主要的降解产物.

Dielectric barrier discharge induced degradation of 3,4-dichloroaniline in aqueous solution

In this study, non-thermal plasma produced by dielectric barrier discharge (DBD) was adopted to remove the 3, 4-DCA in water. The effects of discharge power, air flow rate, metal ions (Fe2+, Cu2+) and titanium dioxide photocatalyst on the removal efficiency of 3, 4-DCA were tested and the byproducts and possible decomposition mechanism were analyzed. The experimental results showed that the DBD method has a favorable removal efficiency for 3, 4-DCA. About 92.5% can be removed after 6 min DBD decomposition with 30 mg·L-1 initial concentration, 80 W discharge power and 1 L·min-1 air flow rate. The removal rate of 3, 4-DCA increases significantly with the increase of air flow rate, while adding a certain amount of ferrous ion (Fe2+) and TiO2 photocatalyst can also increase the removal rate of 3, 4-DCA. The degradation reaction of 3, 4-DCA by DBD can be described by first-order reaction kinetics. Dechlorination, deamination and aromatic ring-opening reactions were found to be the major reactions and ethylene dichloride was found to be the major degradation product.