常温下过硫酸盐氧化降解水中对氯苯胺  

Oxidation degradation of p-chloroaniline in water by persulphate at ambient temperatures

作　　者：杜肖哲[1] 张永清[1,2,3] 

机构地区：[1]华南理工大学环境科学与工程学院,广州510000 [2]工业聚集区污染控制与生态修复教育部重点实验室,广州510006 [3]广东省环境污染控制与修复技术重点实验室,广州510275

出　　处：《环境化学》2012年第6期880-884,共5页Environmental Chemistry

基　　金：广东省国际合作项目(No2010B050200007);广东省环境污染控制与修复技术重点实验室开放研究基金资助项目(2011k0013);中央高校基本科研业务费专项资金资助(2011ZM0054)

摘　　要：研究了常温下初始pH值对过硫酸盐氧化降解水中对氯苯胺(PCA)动力学过程的影响,并探讨了PCA降解的机理.结果表明,室温下,PCA的降解符合准一级动力学方程;pH值为3、5、7、9和11时,其一级动力学常数k分别为0.03×10-4、0.12×10-4、0.28×10-4、0.26×10-4和0.27×10-4s-1;酸性体系不利于PCA的降解,pH 7时PCA的降解速率最大,半衰期为6.88 h.通过LC/MS和GC/MS鉴定得到PCA降解的4种主要中间产物,分别为对氯硝基苯、对苯醌、1-(4氯苯)-3苯基脲和5-氯-2-(4氯苯二氮烯)苯酚,并在此基础上探讨了过硫酸盐氧化降解PCA的可能途径.Effect of pH on the degradation kinetics of p-chloroaniline （PCA） by persulp.hate in aqueous solutions was investigated at ambient temperature. Intermediate products of the oxidation process were characterized using LC/MS and GC/MS techniques. The PCA degradation was found to follow a pseudo-first-order decay model. At 20 °C, [Na2S208]0 =2.50 mmol. L-1, [PCA]0 =0.05 mmol. L-1, the pseudo-first-order rate constants of PCA degradation by persulphate were 0. 03 x 10-4, 0. 12 x 10-4, 0. 28 x10-4, 0. 26 x 10-4 and 0. 27 x 10-4 s-1 at pH 3, 5, 7, 9 and 11, respectively. The maximum PCA degradation occurred at pH 7. 4-chloronitrobenzene, 1 - （ 4-chlorophenyl） -3 -phenylurea, 5 -chloro-2- （ （ 4-chlorophenyl ） diazenyl ） phenol and p-benzoquinone were identified as the major intermediates of PCA oxidation by persulphate. Tentative pathway for the degradation of PCA was proposed. The degradation of PCA in groundwater and buffer solution by persulphate was also tested.

关 键 词：过硫酸盐 对氯苯胺 降解 动力学 机理 

分 类 号：X703[环境科学与工程—环境工程]