二氧化氯预氧化对消毒副产物生成潜能的作用规律研究

Effect of chlorine dioxide pre-oxidation on disinfection by-products formation

二氧化氯(ClO2)已广泛应用于微污染原水预处理和出厂水消毒处理过程中。研究以腐殖酸溶液为对象,对比分析了预高锰酸钾、预二氧化氯与预氯化后消毒副产物生成潜能的变化特性;重点考察了二氧化氯预氧化过程中反应时间、投加量、溴离子浓度不同影响因素下,经预氧化后消毒副产物的生成潜能变化特性。研究发现:ClO2预氧化削减消毒副产物生成潜能的效果明显优于预氯化(Cl2)和预高锰酸钾(KMnO4)氧化;可削减三氯甲烷(CF)生成潜能、二氯乙腈(DCAN)和三氯硝基甲烷(TCNM)的总生成潜能分别达21.2%、42.2%;随着预氧化时间的延长,CF的生成潜能呈明显增加的规律,DCAN和TCNM的总生成潜能在预氧化时间超过60min后升高;随着二氧化氯投加浓度的变化,CF和DCAN生成潜能均呈先下降后逐步增加的趋势,TCNM生成潜能变化不大;随着溴离子浓度增加,三卤甲烷(THMs)总量升高了57%,同时三溴甲烷所占比例明显增大,溴离子增加使得DCAN及TCNM的生成潜能下降,并逐步转变成为溴代乙腈和溴代硝基甲烷类副产物。

The chlorine dioxide（CIO2 ）has been widely used for the pretreatment of micro-polluted raw water and the finished water. In this paper, through the comparative analysis of pre-potassium permanganate, pre-cblorine dioxide and pre-chlorination on humie add, changes of disinfection by-products formation were studied. The effects of different influencing factors such as reaction time, dosage and bromide ion on CIO2 preoxidation were examined. The effect of CIO2 pre-oxidation on the DBPs formation potential was greater than that of pre-chlorination（Cl2 ）and pre-oxidation of potassium permanganate（KMnO4 ）. The potential of CF, total potential of DCAN and TCNM were reduced by 21.2% and 42. 2%, respectively. With the pre-oxidation time, the potential of CF increased significantly and the total potential of DCAN and TCNM increased after 60 mi- nutes pre-oxidation time. With chlorine dioxide dosage changed,CF and [）CAN formation potential increased gradually after a drop at the beginning, and little change for TCNM. with the increasing in the concentration of bromide ion, the total amount of THMLs increased by 57%, meanwhile, the proportion of bromethol in- creased significantly. The increase of bromine concentration decreased the formation potential of the DCAN and TCNM and they gradually were transformed into hromo-acetonitrile and bromo-nitromethane by-products.