碳纳米管对天然有机质氯化消毒副产物生成的影响

Effects of Carbon Nanotubes on Formation of Disinfection By-Products during Chlorination of Natural Organic Matters

以应用广泛的碳纳米材料多壁碳纳米管(CNTs)和水体中普遍存在的天然有机质(NOMs)为研究对象,探讨CNTs对两种不同种类NOMs(Suwannee river standard humic acid,HASR和Suwannee river standard fulvic acid,FASR)氯化生成消毒副产物的影响。结果表明,与单一NOMs体系相比,CNTs的存在会增加HASR和FASR氯化生成三卤甲烷(trihalomethanes,THMs)和卤代乙酸(halogenated acetic acid,HAAs)的产量和初始速率。这是由于CNTs和NOMs均可以作为消毒副产物的前体物,混合体系中氯化反应活性位点数量增多,因此产量和速率都有所提升。并且,无论体系中是否存在CNTs,HASR生成THMs和HAAs的初始速率均高于FASR,这是因为HASR的芳香共轭程度高于FASR,更易与次氯酸反应。此外,由于CNTs对HASR的吸附量高于FASR,因此CNTs对HASR氯化生成消毒副产物的影响大于FASR。

Multi-wall carbon nanotubes(CNTs)and natural organic matters(NOMs)were chosen as target pollutants in this study.The effects of CNTs on the formation of disinfection by-products during chlorination of different types of NOMs(Suwannee river standard humic acid(HASR)and Suwannee river standard fulvic acid(FASR))were investigated.Compared with the single system of CNTs or NOMs,the presence of CNTs increased the yields and initial formation rates of trihalomethanes(THMs)and halogenated acetic acids(HAAs)in the binary systems.Both CNTs and NOMs could serve as precursors of disinfection by-products,leading to more active sites for chlorination in NOMs-CNTs system.Therefore,the yields and initial formation rates of binary systems increased.Moreover,the initial formation rate of THMs and HAAs formed by HASR were higher than those formed by FASR in the absence and presence of CNTs.This was due to the higher aromaticity of HASR than FASR,which favored the attack of hypochlorous acid.In addition,the adsorption amount of HASR to CNTs was greater than FASR,which resulted in its stronger effects on the formation of disinfection by-products than FASR.