Research Center for Water Environment Technology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan; Department of Environmental Engineering, Faculty of Engineering and Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen, 40002, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, 10330, Thailand.
Research Center for Water Environment Technology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan.
Water Res. 2019 Aug 1;159:214-222. doi: 10.1016/j.watres.2019.05.002. Epub 2019 May 6.
We investigated semiquantitative changes in almost 1000 dissolved organic matter (DOM) features during oxidation with 1 mg of O per liter (mg O/L), 4 mg O/L, or 4 mg O/L + 2.5 mg of HO per liter (advanced oxidation process, AOP) by unknown screening analysis with Orbitrap mass spectrometry. The consequential effects on formation of unknown disinfection by-products (DBPs) by chlorination were evaluated in laboratory-scale experiments. Several hundred unsaturated DOM features with positive oxygen-subtracted double bond equivalents per carbon ((DBE-O)/C) were decomposed by the ozone-only treatment and AOP. The AOP decomposed some saturated (negative (DBE-O)/C)) and reduced molecules, which had negative carbon oxidation states (C). Several hundred saturated oxidation by-products were detected after ozonation and the AOP. After chlorination, the samples pre-treated with ozone alone resulted in higher formation of unknown DBPs than the AOP pre-treated sample or the sample without oxidation. Over half of the DBP precursors, estimated by electrophilic substitution, were not totally decomposed by any oxidation process, but they were increased after the ozone-only process and AOP. DBP precursors produced by the ozone-only process or AOP formed unique unknown DBPs. Therefore, post-treatment processes after oxidation and before chlorination are important to minimize formation of unknown DBPs.
我们通过未知筛选分析，利用轨道阱质谱法，研究了在 1mg/L、4mg/L 或 4mg/L+2.5mg/L 每升过氧（高级氧化工艺，AOP）氧化过程中近 1000 种溶解有机物（DOM）特征的半定量变化。通过实验室规模的实验，评估了氯化对形成未知消毒副产物（DBP）的影响。仅臭氧处理和 AOP 分解了数百种具有正氧消去双键当量/碳比 ((DBE-O)/C) 的不饱和 DOM 特征。AOP 分解了一些饱和（负 (DBE-O)/C）和还原分子，它们具有负碳氧化态 (C)。在臭氧处理和 AOP 之后，检测到了数百种饱和氧化副产物。在氯化后，单独用臭氧预处理的样品比 AOP 预处理的样品或未经氧化的样品产生了更高的未知 DBP。通过亲电取代估计的一半以上的 DBP 前体并未被任何氧化过程完全分解，但在单独的臭氧过程和 AOP 后增加了。仅臭氧过程或 AOP 产生的 DBP 前体形成了独特的未知 DBP。因此，在氯化之前进行氧化后的后处理过程对于最小化未知 DBP 的形成非常重要。
