摘要
研究了UV/H_2O_2对水中三氯生(TCS)的降解;考察了H_2O_2用量,pH值,常见无机阴离子(如HCO_3^-,Cl-,NO_3^-和SO_4^(2-))和天然有机物质(NOM)对TCS去除的影响;探讨了TCS的降解产物和转化机理.结果表明:TCS在UV/H_2O_2中的降解符合准一级反应动力学.随着H_2O_2用量的提高,TCS的降解效率也逐渐提高,但是过量的H_2O_2会和TCS竞争羟基自由基(HO·).TCS在pH 8.5时的降解效率高于研究的其它pH值(即pH 5.3-7.4).虽然HCO_3^-是一种常见的HO·淬灭剂,但是它对TCS的降解影响较小;其它无机阴离子(Cl-,NO_3^-和SO_4^(2-))对TCS的去除几乎无影响.NOM的存在会抑制TCS的降解,且NOM浓度越高,抑制作用越明显.由于实际水样中的HCO_3^-和NOM与TCS竞争HO·,TCS在实际水体中的降解与纯水中的相比受到一定程度地抑制.利用液相色谱-超高解析度四级杆飞行时间串联质谱仪(LC-QTOF/MS)检出26种TCS的降解产物,根据这些鉴定的反应产物推测TCS可能的转化机理主要包括6种不同的反应路径,分别为脱氯氢化,脱氯羟基化,羟基化,脱氢反应,环化反应和醚键断裂.
The degradation of triclosan(TCS)by UV/H2O2 was investigated in this paper.The effects of H2O2 dose,pH,common inorganic anions(e.g.,HCO3?,Cl?,NO3?and SO4 2?)and natural organic matter(NOM)on the removal of TCS were also evaluated.Finally,the degradation products and transformation mechanism of TCS by UV/H2O2 were studied.The results showed that the degradation of TCS in UV/H2O2 system followed the pseudo first-order kinetics.The degradation efficiency of TCS enhanced gradually with the increase in H2O2 dose,while excess H2O2 could compete with TCS for hydroxyl radical(HO?).The degradation efficiency of TCS at pH 8.5 was higher than those at other studied pH values(i.e.,pH 5.3-7.4).Though HCO3?is a common scavenger of HO?,it had little influence on the degradation of TCS,while the other inorganic anions including Cl?,NO3?and SO4 2?could hardly affect the removal of TCS.The presence of NOM could inhibit TCS degradation and the inhibiting effect enhanced with the increase in the concentration of NOM.Compared with the removal of TCS in pure water,its degradation in real waters was inhibited because of the competition of HCO3?and NOM in real waters with TCS for HO?.Twenty-six degradation products of TCS were detected using a ultra-high definition accurate-mass quadrupole time-of-flight tandem mass spectrometer coupled with a high performance liquid spectrometer(LC-QTOF/MS).Based on these identified reaction products,the possible transformation mechanism of TCS by UV/H2O2 was proposed revealing six different degradation pathways,including dechlorination-hydrogenation,dechlorination-hydroxylation,hydroxylation,dehydrogenation,cyclization and ether cleavage.
作者
付永胜
史鸿乐
刘义青
周高峰
FU Yong-sheng;SHI Hong-le;LIU Yi-qing;Zhou Gao-feng(Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 611756,China)
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2018年第2期616-626,共11页
China Environmental Science
基金
长江上游水与资源管理的可持续利用联合研究项目(2012DFG91520)
成都市科技局项目(2014-HM01-00278-SF)
作者简介
付永胜(1963-),男,四川成都人,教授,博士,研究方向为水污染控制.发表论文60余篇.;责任作者,讲师,swjtu7001@163.com
