Characterization of disinfection byproduct formation and associated changes to dissolved organic matter during solar photolysis of free available chlorine
Characterization of disinfection byproduct formation and associated changes to dissolved organic matter during solar photolysis of free available chlorine
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游离有效氯的太阳光解过程中消毒副产物形成和溶解有机物相关变化的表征
DOI：
10.1016/j.watres.2018.09.022
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发表时间：
2018
期刊：
影响因子：
12.8
通讯作者：
Michael C Dodd
中科院分区：
文献类型：
--
作者：
Tessora R Young;Wentao Li;Alan Guo;Gregory V Korshin;Michael C Dodd
含氯沃茨的太阳辐射增强了耐氯病原体（例如，隐孢子虫卵囊），通过在紫外线B-UVA波长的太阳光（290-400 nm）下光解游离有效氯（FAC）过程中原位形成臭氧、羟基自由基和其他活性物质。然而，相应的影响监管消毒副产物（DBP）的形成和相关的溶解有机物（DOM）的属性仍然不清楚。在这项工作中，相比暗氯化，在一系列条件下，阳光驱动的FAC光解被发现产生更高的DBP水平，DOM发色团和荧光团的耗尽，优先去除酚基团相对于羧酸基团，较大的腐殖物质降解为较小分子量的化合物。对照实验表明，DBP水平的增加不是由于DOM的直接光解和随后与FAC的暗反应，而是由于DOM与FAC和活性物质（例如，O3、HO·、Cl·、Cl2·-、ClO·）。由于太阳能氯光解可以使耐氯病原体在远低于单独氯化的CTFAC值下失活，因此这种方法固有的DBP形成的增加可能在一定程度上被在显著降低的CTFAC下操作的能力所抵消。尽管如此，这些研究结果表明，太阳能氯光解的应用将需要密切关注DBP形成的潜在影响。
Solar irradiation of chlorine-containing waters enhances inactivation of chlorine-resistant pathogens (e.g., Cryptosporidium oocysts), through in situ formation of ozone, hydroxyl radical, and other reactive species during photolysis of free available chlorine (FAC) at UVB-UVA wavelengths of solar light (290–400 nm). However, corresponding effects on regulated disinfection byproduct (DBP) formation and associated dissolved organic matter (DOM) properties remain unclear. In this work, when compared to dark chlorination, sunlight-driven FAC photolysis over a range of conditions was found to yield higher DBP levels, depletion of DOM chromophores and fluorophores, preferential removal of phenolic groups versus carboxylic acid groups, and degradation of larger humic substances to smaller molecular weight compounds. Control experiments showed that increased DBP levels were not due to direct DOM photolysis and subsequent dark reactions with FAC, but to co-exposure of DOM to FAC and reactive species (e.g., O3, HO•, Cl•, Cl2•-, ClO•) generated by FAC photolysis. Because solar chlorine photolysis can enable inactivation of chlorine-resistant pathogens at far lowerCTFACvalues than chlorination alone, the increases in DBP formation inherent to this approach can likely be offset to some extent by the ability to operate at significantly decreasedCTFAC. Nonetheless, these findings demonstrate that applications of solar chlorine photolysis will require careful attention to potential impacts on DBP formation.