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.
Environ Sci Technol. 2018 Mar 20;52(6):3392-3401. doi: 10.1021/acs.est.7b04765. Epub 2018 Mar 5.
Molecular changes in dissolved organic matter (DOM) from treatment processes at two drinking water treatment plants in Japan were investigated using unknown screening analysis by Orbitrap mass spectrometry. DOM formulas with carbon, hydrogen and oxygen (CHO-DOM) were the most abundant class in water samples, and over half of them were commonly found at both plants. Among the treatment processes, ozonation induced the most drastic changes to DOM. Mass peak intensities of less saturated CHO-DOM (positive (oxygen subtracted double bond equivalent per carbon (DBE-O)/C)) decreased by ozonation, while more saturated oxidation byproducts (negative (DBE-O)/C) increased and new oxidation byproducts (OBPs) were detected. By Kendrick mass analysis, ozone reactions preferred less saturated CHO-DOM in the same alkylation families and produced more saturated alkylation families of OBPs. Following ozonation, biological activated carbon filtration effectively removed <300 Da CHO-DOM, including OBPs. Following chlorination, over 50 chlorinated formulas of disinfection byproducts (DBPs) were found in chlorinated water samples where at least half were unknown. Putative precursors of these DBPs were determined based on electrophilic substitutions and addition reactions. Ozonation demonstrated better decomposition of addition reaction-type precursors than electrophilic substitution-type precursors; over half of both precursor types decreased during biological activated carbon filtration.
采用轨道阱质谱的未知筛选分析方法，研究了日本两家饮用水处理厂处理过程中溶解有机物 (DOM) 的分子变化。水中样品中最丰富的 DOM 类是含碳、氢和氧的 DOM 分子式 (CHO-DOM)，其中超过一半在两个工厂中都普遍存在。在处理过程中，臭氧氧化对 DOM 造成的变化最为剧烈。臭氧氧化导致不饱和 CHO-DOM（正 (氧扣除双键等价物/碳 (DBE-O)/C)) 的质峰强度降低，而更多的饱和氧化副产物（负 (DBE-O)/C) 增加，并检测到新的氧化副产物 (OBPs)。通过 Kendrick 质量分析，臭氧反应优先在相同的烷基化家族中与不饱和 CHO-DOM 反应，并产生更多的饱和烷基化家族的 OBPs。臭氧氧化后，生物活性炭过滤有效地去除了 <300 Da 的 CHO-DOM，包括 OBPs。氯化后，在氯化水中发现了 50 多种氯化消毒副产物 (DBPs) 的氯化公式，其中至少有一半是未知的。根据亲电取代和加成反应，确定了这些 DBP 的假定前体。臭氧氧化对加成反应型前体的分解效果优于亲电取代型前体；在生物活性炭过滤过程中，这两种前体类型中有一半以上的含量都减少了。
