Breakpoint chlorination can be commonly observed in the chlorination of water treatments when ammonia is present. In this study, it was found that breakpoint chlorination can remarkably eliminate a ubiquitous and chlorine-refractory micropollutant, carbamazepine (CBZ), with the removal of 72% at neutral condition. At neutral pH, low CBZ elimination was observed at a chlorine/ammonia molar ratio (Cl/N) of 1.0 and higher CBZ elimination was observed as Cl/N ratio increased from 1.0 to 1.6 (breakpoint), indicating that CBZ elimination was closely related to the generation and decomposition of chloramines. The chloramines generation and decomposition rates were affected by the pH, so that the CBZ elimination rate was highest at pH 7.0 and lower in acidic and basic solutions (pH 5.5 and pH 9.5, respectively). The CBZ elimination at pH 7.0 was 72.4% after 10 min of breakpoint chlorination, while reaction times about 30 min and 60 min were required to achieve the same elimination at pH 5.5 and pH 9.5, respectively. Breakpoint chlorination of CBZ was strongly suppressed by radical scavenger tBuOH and moderately suppressed by N₂ purging, the inhibiting ratios being 87.7% and 27.8% at breakpoint, respectively. Electron spin resonance experiments suggested that unidentified radicals were generated by breakpoint chlorination. The

在存在氨的情况下，在水处理的氯化过程中通常会观察到断点氯化作用。在这项研究中，发现断点氯化可显着消除普遍存在且耐氯的微污染物卡马西平（CBZ），在中性条件下可去除72％。在中性pH值下，氯/氨气摩尔比（Cl / N）为1.0时，CBZ的去除率较低，而当Cl / N比值从1.0增加到1.6（断裂点）时，CBZ的去除率较高，这表明CBZ的去除率密切相关生成和分解氯胺。pH值影响氯胺的生成和分解速率，因此CBZ消除速率在pH 7.0时最高，而在酸性和碱性溶液（分别为pH 5.5和pH 9.5）中则较低。pH 7.0时CBZ消除率为72。断点氯化反应10分钟后达到4％，而分别在pH 5.5和pH 9.5下达到相同的消除反应需要大约30分钟和60分钟的反应时间。自由基清除剂可强烈抑制CBZ的断点氯化t BuOH和被N ₂吹洗适度地抑制，在断点处的抑制率分别为87.7％和27.8％。电子自旋共振实验表明，断点氯化反应产生了无法识别的自由基。这