State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China.
J Hazard Mater. 2010 Jan 15;173(1-3):82-6. doi: 10.1016/j.jhazmat.2009.08.051. Epub 2009 Aug 19.
The stability of haloacetamides (HAcAms) such as dichloroacetamide (DCAcAm) and trichloroacetamide (TCAcAm) was studied under different experimental conditions. The yield of HAcAms during aspartic acid (Asp) chlorination was measured at different molar ratio of chlorine atom to nitrogen atom (Cl/N), pH and dissolved organic carbon (DOC) mainly consisted of humic acid (HA) mixture. Ascorbic acid showed a better capacity to prevent the decay of DCAcAm and TCAcAm than the other two dechlorinating agents, thiosulfate and sodium sulfite. Lower Cl/N favored the DCAcAm formation, implying that breakpoint chlorination might minimize its generation. The pH decrease could lower the concentration of DCAcAm but favored dichloroacetonitrile (DCAN) formation. DCAcAm yield was sensitive to the DOC due to higher chlorine consumption caused by HA mixture. Two possible pathways of DCAcAm formation during Asp chlorination were proposed. Asp was an important precursor of DCAN, DCAcAm and dichloroacetic acid (DCAA), and thus removal of Asp before disinfection may be a method to prevent the formation of DCAcAm, DCAN and DCAA.
研究了卤乙酰胺（HAcAms）如二氯乙酰胺（DCAcAm）和三氯乙酰胺（TCAcAm）在不同实验条件下的稳定性。在不同的氯原子与氮原子摩尔比（Cl/N）、pH 值和以腐殖酸（HA）混合物为主的溶解有机碳（DOC）条件下，测量了天门冬氨酸（Asp）氯化过程中 HAcAms 的产率。抗坏血酸比另外两种脱氯剂亚硫酸氢盐和亚硫酸钠更能防止 DCAcAm 和 TCAcAm 的衰减。较低的 Cl/N 有利于 DCAcAm 的形成，这表明在断键氯化时可能会最小化其生成。pH 值降低会降低 DCAcAm 的浓度，但有利于二氯乙腈（DCAN）的形成。由于 HA 混合物导致的氯消耗增加，DCAcAm 的产率对 DOC 很敏感。提出了 Asp 氯化过程中 DCAcAm 形成的两种可能途径。Asp 是 DCAN、DCAcAm 和二氯乙酸（DCAA）的重要前体，因此在消毒前去除 Asp 可能是防止 DCAcAm、DCAN 和 DCAA 形成的一种方法。
