Wang Xue-Ning, Zhang Bing-Liang, Pan Bing-Cai
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China.
Huan Jing Ke Xue. 2021 Aug 8;42(8):3847-3857. doi: 10.13227/j.hjkx.202012187.
As an emerging advanced oxidation technology, UV/chlorine treatment is capable of effectively oxidizing various organic pollutants. Till now, the transformation of dissolved effluent organic matter (dEfOM) in real wastewater during UV/chlorine treatment remains unclear. In this study, ultraviolet and fluorescence spectroscopy were combined with Fourier transform ion cyclotron resonance mass spectrometry to probe the transformation of dEfOM in two municipal secondary effluents during UV/chlorine treatment. Meanwhile, the newly formed chlorinated byproducts (Cl-BPs) are particularly concerned. Generally, aromatic compounds and fluorescent components could be readily removed after UV/chlorine treatment, and most of the dEfOM underwent transformation rather than mineralization. Protein-like components, which accounted for the largest proportion of fluorescent components, were subject to a preferential reaction. UV/chlorine treatment could result in the degradation of CHOS compounds and the formation of CHO compounds. During this process, unsaturated and reduced compounds of large molecules were preferentially removed, whereas saturated and oxidized compounds with low molecular weight were produced. Moreover, the concentrations of trihalomethanes and haloacetic acids increased substantially after UV/chlorine treatment. In total, 255 and 133 Cl-BPs were detected in the respective effluents after UV/chlorine treatment. In addition, 12 and 43 possible precursor-Cl-BPs pairs were identified, respectively, based on electrophilic substitution and addition reactions by means of mass difference analysis. This study is expected to provide fundamental information for practical application of the UV/chlorine treatment process.
作为一种新兴的高级氧化技术，紫外线/氯处理能够有效氧化各种有机污染物。到目前为止，紫外线/氯处理过程中实际废水中溶解性出水有机物（dEfOM）的转化情况仍不清楚。在本研究中，将紫外光谱和荧光光谱与傅里叶变换离子回旋共振质谱相结合，以探究紫外线/氯处理过程中两种城市二级出水中dEfOM的转化情况。同时，新形成的氯化副产物（Cl-BPs）尤其受到关注。一般来说，紫外线/氯处理后芳香族化合物和荧光成分很容易被去除，并且大多数dEfOM发生了转化而非矿化。占荧光成分比例最大的类蛋白质成分优先发生反应。紫外线/氯处理会导致CHOS化合物的降解和CHO化合物的形成。在此过程中，大分子的不饱和和还原态化合物优先被去除，而生成了低分子量的饱和和氧化态化合物。此外，紫外线/氯处理后三卤甲烷和卤乙酸的浓度大幅增加。紫外线/氯处理后的出水中分别检测到255种和133种Cl-BPs。此外，通过质量差分析，基于亲电取代和加成反应分别鉴定出12对和43对可能的前体-Cl-BPs。本研究有望为紫外线/氯处理工艺的实际应用提供基础信息。
