Environment and Industrial Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, India.
Water Environ Res. 2012 Nov;84(11):2003-9. doi: 10.2175/106143012x13415215906735.
Formation character of brominated-trihalomethanes (Br-THMs) in chlorinated seawater and its dependence on applied chlorine dose, reaction time, and temperature were investigated in the laboratory. Seawater was collected from the east coast of India and a chlorine dose of 1, 3, 5, and 10 ppm was each applied at a temperature of 20, 30, and 40 degrees C to investigate the yield and kinetics of Br-THMs formation. Qualitative and quantitative estimation of THM formation at various intervals of time ranging from 5 min to 168 h was determined by a gas chromatograph equipped with an electron capture detector (GC-ECD). Chlorine dose, chlorine contact time, and reaction temperature positively affected the load of THMs. The ratio of chlorine dose to halogen incorporation decreased from 12% to 5% with increasing applied chlorine dose from 1 to 10 ppm. Significant levels of THMs were found to be formed within 0.5 h of reaction, followed by a very slow rate of formation. Elevated temperature favored both increased rate of formation and overall THM yield. The formation order of different trihalomethane species at all studied temperatures was observed to be bromodichloromethane (CHCl2Br) < dibromochloromethane (CHClBr2) < bromoform (CHBr3). Formation of chloroform was not observed, and bromoform was the dominant (96% to 98%) among the three THM species formed.
在实验室中研究了氯化海水中溴代三卤甲烷（Br-THMs）的形成特征及其对施加氯剂量、反应时间和温度的依赖性。采集了来自印度东海岸的海水，并在 20、30 和 40°C 的温度下分别施加 1、3、5 和 10ppm 的氯剂量，以研究 Br-THMs 形成的产率和动力学。通过配备电子俘获检测器的气相色谱仪（GC-ECD），在从 5 分钟到 168 小时的不同时间间隔内，对 THM 形成的定性和定量估计。氯剂量、氯接触时间和反应温度对 THMs 的负荷有积极影响。随着施加氯剂量从 1ppm 增加到 10ppm，氯剂量与卤素掺入的比例从 12%降低到 5%。在反应 0.5 小时内发现形成了大量的 THMs，随后形成速度非常缓慢。升高的温度有利于形成速度的提高和总 THM 产率的提高。在所有研究温度下，不同三卤甲烷物种的形成顺序为二氯溴甲烷（CHCl2Br）<二溴氯甲烷（CHClBr2）<溴仿（CHBr3）。未观察到氯仿的形成，而溴仿是三种形成的 THM 物种中占主导地位（96%至 98%）。
