Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China; Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, Australia.
Institut de Chimie des Milieux et des Matériaux, IC2MP UMR 7285 CNRS, Université de Poitiers, France; Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, Australia.
Water Res. 2020 Apr 1;172:115463. doi: 10.1016/j.watres.2019.115463. Epub 2020 Jan 7.
The presence of Dissolved Organic Matter (DOM) can exert a strong influence on the effectiveness of the UV/chlorine process. This study examined the impact of five DOM isolates with different characteristics on the degradation kinetics of model contaminant primidone (PM) during UV/chlorine treatment. The formation of Disinfection By-Products (DBPs) from DOM after 15-min UV/chlorine treatment followed by 24 h chlorination was investigated and compared with chlorination alone. The use of chemical probes and radical scavengers revealed that OH and ClO• were the main radical species responsible for the loss of PM at acidic and alkaline conditions, respectively. All tested DOM isolates significantly inhibited the decay of PM. A strong negative correlation (>0.93) was observed between the decay rate constants of PM and SUVA of DOM isolates, except for EfOM isolate, which induced the strongest inhibitory effect due to its higher abundance in sulfur-containing functional groups (i.e., sink of OH/Cl radicals). Compared with chlorination, the formation of Adsorbable Organic Chlorine (AOCl) and Trichloromethane (TCM) during the UV/Chlorine process was enhanced and hindered for low SUVA isolates and high SUVA DOM, respectively. However, Dichloroacetonitrile (DCAN) formation was generally lower for all isolates except for Ribou Reservoir DOM at pH 8.4 because of its high reactive nitrogenous DBP precursors at caustic conditions. However, when normalized to the chlorine consumed, the UV/Chlorine process always led to a lower DBPs formation compared with chlorination alone.
溶解有机物（DOM）的存在会对 UV/氯工艺的效果产生强烈影响。本研究考察了五种具有不同特性的 DOM 分离物对模型污染物扑米酮（PM）在 UV/氯处理过程中降解动力学的影响。研究了 15 分钟 UV/氯处理后 DOM 形成的消毒副产物（DBP），并在 24 小时氯化后与单独氯化进行了比较。使用化学探针和自由基清除剂表明，OH 和 ClO•是在酸性和碱性条件下导致 PM 损失的主要自由基种类。所有测试的 DOM 分离物均显著抑制了 PM 的衰减。除 EfOM 分离物外，PM 的衰减速率常数与 DOM 分离物的 SUVA 值之间存在很强的负相关关系（>0.93），这是由于其含硫官能团（即 OH/Cl 自由基的汇）的含量较高而导致的最强抑制效应。与氯化相比，在 UV/氯过程中，低 SUVA 分离物和高 SUVA DOM 分别促进和阻碍了可吸附有机氯（AOCl）和三氯甲烷（TCM）的形成。然而，除了 Ribou 水库 DOM 在 pH8.4 下由于其在碱性条件下具有高反应性含氮 DBP 前体外，所有分离物的二氯乙腈（DCAN）形成通常较低。然而，当归一化为消耗的氯时，UV/氯工艺总是比单独氯化导致形成的 DBPs 更少。
