School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
Chemosphere. 2013 Jun;91(11):1477-85. doi: 10.1016/j.chemosphere.2012.12.014. Epub 2013 Jan 9.
Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation.
二氧化氯（ClO2）常用于水处理过程中去除异味、颜色和味道。由于氯酸盐的形成问题，ClO2 预氧化后通常会进行氯化或氯胺化。我们研究了连续 ClO2-氯化和 ClO2-氯胺化过程中规管和新兴消毒副产物（DBPs）的形成。为了阐明 DBPs 形成与天然有机物（NOM）特性之间的关系，我们通过荧光、傅里叶变换红外光谱（FTIR）以及大小和树脂分级技术，对 ClO2 氧化前后 NOM 的性质变化进行了表征。ClO2 预氧化破坏了 NOM 的芳香性和共轭结构，并将大的芳香性和长链脂肪族有机物转化为小的亲水性有机物。单独使用 ClO2 不会产生大量的三卤甲烷（THMs）和卤乙酸（HAAs），但会产生亚氯酸盐。ClO2 预氧化可降低后续氯化过程中 THMs、HAAs、卤乙腈（HAN）和水合氯醛（CH）的含量，但在氯胺化过程中则不会降低 THMs 的含量。增加 ClO2 剂量可增强除卤代硝基甲烷（HNMs）和卤代酮（HKs）之外的大多数 DBPs 的去除效果。溴化物的存在增加了总 DBPs 的形成量，并且使 DBPs 更多地转化为溴代产物。溴在 ClO2 处理过的样品中含量更高。结果表明，在原水和受污染的水中，氯化前进行 ClO2 预氧化可用于控制 THM、HAA 和 HAN，但氯酸盐的形成是一个问题，而且 HNMs 和 HKs 不能通过 ClO2 预氧化有效控制。
