Halobenzoquinones are frequently detected as disinfection by-products in drinking water. Among identified halobenzoquinones, 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ) is particularly toxic and is frequently detected in drinking water. Synthetic aromatic antioxidants discharged to source water may increase the risk of 2,6-DCBQ formation, as many studies suggest that aromatic compounds are the most likely precursors to 2,6-DCBQ. Herein, we investigated the formation of 2,6-DCBQ from chlorination of three model aromatic antioxidants, including 3-tert-butyl-4-hydroxyanisole (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and bis(4-tert-butylphenyl)amine (BBPA). Only BBPA produced 2,6-DCBQ under chlorination, while chlorination of BHA and BHT formed α, β-unsaturated C₄-dicarbonyl ring-opening products and phenolic compounds. Based on mass balance and intermediate transformation analysis, mechanisms for the formation of 2,6-DCBQ from BBPA chlorination involved hydrolysis, tert-butyl group cleavage, chlorine substitution, desamination and oxidation. Mitigating aromatic compounds will be an efficient method for 2,6-DCBQ control, such as pre-ozonation, because the intermediates involved in 2,6-DCBQ formation were aromatic compounds. Real water samples from two drinking water treatment plants (DWTPs), one with pre-ozonation (DWTP 2) and the other without pre-ozonation (DWTP1), were analyzed. The two DWTPs were built along the Yangtse river in Nanjing city. Raw water parameters from the two DWTPs, including dissolved organic carbon (DOC), UV absorbance at 254 nm (UV₂₅₄) and NH₃–N, indicated the water quality between these sources was similar. Pre-ozonation in DWTP 2 vanished 2,6-DCBQ in raw water. Concentrations of 2,6-DCBQ in finished water from DWTP 1 (5.69 ng/L) was higher than concentrations generated from DWTP 2 (1.31 ng/L). These results demonstrate that pre-ozonation, granular activated carbon (GAC) and quartz sand treatments at DWTP 2 remove more 2,6-DCBQ precursors than the conventional quartz sand and GAC treatments in DWTP 1. These results suggest the pre-ozonation, GAC and quartz sand treatments can help minimize concentrations of 2,6-DCBQ generated in DWTPs.

卤代苯醌经常被检测为饮用水中的消毒副产物。在已确定的卤代苯醌中，2,6-二氯-1,4-苯醌 (2,6-DCBQ) 毒性特别大，经常在饮用水中检测到。排放到水源中的合成芳香族抗氧化剂可能会增加 2,6-DCBQ 形成的风险，因为许多研究表明芳香族化合物最有可能是 2,6-DCBQ 的前体。在此，我们研究了 3-叔丁基-4-羟基苯甲醚 (BHA)、2,6-二叔丁基-4-甲基苯酚 (BHT)三种模型芳族抗氧化剂氯化形成 2,6-DCBQ和双(4-叔丁基苯基)胺(BBPA)。只有 BBPA 在氯化下产生 2,6-DCBQ，而 BHA 和 BHT 氯化形成α，β-不饱和C ₄ -二羰基开环产物和酚类化合物。基于质量平衡和中间转化分析，BBPA 氯化形成 2,6-DCBQ 的机制涉及水解、叔-丁基裂解、氯取代、脱氨基和氧化。减少芳香族化合物将是控制 2,6-DCBQ 的有效方法，例如预臭氧化，因为参与 2,6-DCBQ 形成的中间体是芳香族化合物。分析了来自两个饮用水处理厂 (DWTP) 的真实水样，一个具有预臭氧化 (DWTP 2)，另一个没有预臭氧化 (DWTP1)。两座污水处理厂建在南京市长江沿岸。来自两个 DWTP 的原水参数，包括溶解有机碳 (DOC)、254 nm 处的紫外吸光度 (UV ₂₅₄ ) 和 NH ₃-N，表示这些水源之间的水质相似。DWTP 2 中的预臭氧化使原水中的 2,6-DCBQ 消失。来自 DWTP 1 的成品水中的 2,6-DCBQ 浓度 (5.69 ng/L) 高于来自 DWTP 2 的浓度 (1.31 ng/L)。这些结果表明，DWTP 2 中的预臭氧化、颗粒活性炭 (GAC) 和石英砂处理比 DWTP 1 中的常规石英砂和 GAC 处理去除了更多的 2,6-DCBQ 前体。这些结果表明预臭氧化、GAC和石英砂处理有助于将 DWTP 中产生的 2,6-DCBQ 浓度降至最低。