巢湖水中溶解性有机物分子大小分布、亲疏水性与消毒副产物的生成势

摘要

以微污染巢湖原水为研究对象,考察了原水中溶解性有机物(DOM)的分子大小分布模式和亲疏水性分子组成规律,并对其氯化消毒副产物(DBPs)的生成潜能进行了系统研究.巢湖原水中的DOM主要以小分子的形式存在.亲疏水性组分的分布为:强疏水组分占43.48％,弱疏水组分占17.39％,亲水组分占39.13％.在微污染巢湖原水有机物中,分子大小(MS)＜1 kDa和10～30 kDa的组分具有最大的三卤甲烷(THMs)和卤代酮(HKs)等含碳消毒副产物(C-DBPs)生成潜能;同时,MS为5～10 kDa的有机物具有较高的二氯乙腈(DCAN)和三氯硝基甲烷(TCNM)等含氮消毒副产物(N-DBPs)生成潜能.不同亲疏水性组分的THMs和HKs生成潜能从大到小依次均为强疏水组分＞亲水组分＞弱疏水组分.同时,强疏水组分生成最多的N-DBPs,弱疏水组分次之,而亲水组分最少.%In this study,distribution of molecular size,composition pattern of hydrophilic and hydrophobic components,and disinfection by-product (DBP) formation potential during chlorination for dissolved organic matters (DOM) in micro-polluted raw water from Chaohu Lake were investigated.The results showed that DOM in raw water from Chaohu Lake were mostly organic compounds with small molecular size,and proportions of hydrophobic,weak hydrophobic and hydrophilic components were 43.48 ％,17.39 ％ and 39.13 ％,respectively.After chlorination incubation,the fraction with molecular size (MS) ＜ 1 kDa and of 10 ～ 30 kDa showed the highest formation potentials for carbonaceous DBPs (C-DBPs) like trihalomethanes (THMs) and haloketones (HKs).Dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM) were the only nitrogenous DBPs (N-DBPs) detected in this study,which were mostly formed by the fraction with MS of 5 ～ 10 kDa.For different hydrophilic and hydrophobic components,formation potentials of both THMs and HKs followed the same order of hydrophobic components ＞ hydrophilic components ＞ weak hydrophobic components.Meanwhile,hydropbobic components also formed the most yields of N-DBPs,followed by the weak hydrophobic components,then hydrophilic components.