| 饮用水中含氮消毒副产物三氯硝基甲烷的形成过程和影响因素 |
| 摘要点击 4206 全文点击 2343 投稿时间：2012-07-21 修订日期：2012-10-08 |
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| 中文关键词 饮用水 三氯硝基甲烷 前体物 形成机制 影响因素 |
| 英文关键词 drinking water trichloronitromethane(TCNM) precursor formation mechanism influencing factors |
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| 中文摘要 |
| 采用气相色谱/质谱法,选择甲基叔丁基醚为萃取剂,1,2-二溴丙烷为内标物,建立了含氮消毒副产物三氯硝基甲烷(TCNM)的测定方法. 以甲胺为前体物,考察了饮用水氯化消毒过程中三氯硝基甲烷(TCNM)的生成过程及影响因素. 结果表明,pH在碱性条件下TCNM的生成量比中性和酸性条件下高,TCNM的生成量随着pH的增大而逐渐提高. 在投氯量2~8 mmol·L-1的范围内,TCNM的生成量随着投氯量的增加而提高,当投氯量由8 mmol·L-1增加到12 mmol·L-1时,因自由氯的浓度较高,甲胺还通过其它路径发生反应生成了腈类和醛类,从而使TCNM的生成量降低. 在甲胺投加量0.5~4 mmol·L-1的范围内,TCNM的生成量随着甲胺和氯胺的投加量的增加而提高. 在10~30℃范围内,温度对甲胺生成TCNM的影响较明显,温度越高,TCNM的生成量越高. 甲胺氯化形成TCNM的过程符合亲电反应的机制,HClO和ClO-可以作为亲电试剂进攻甲胺最终形成TCNM. |
| 英文摘要 |
| A novel method is described in this paper, which uses methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of nitrogenous disinfection byproduct trichloronitromethane (TCNM) by gas chromatography mass spectrometry (GC-MS). The formation process of TCNM and its influencing factors were evaluated with methylamine as the precursor during chlorination. The results indicated that the TCNM amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the TCNM amount increased with the increase of pH value. It was found that the TCNM amount increased with the increase of chlorine addition when the chlorine dosage was in the range of 2-8 mmol·L-1. However, the TCNM amount was reduced when the chlorine dosage was enhanced from 8 mmol·L-1 to 12 mmol·L-1, under which conditions the concentration of free chlorine was higher and methylamine was turned into nitriles and aldehydes through other reactions. It was also found that the TCNM amount increased with the increase of methylamine addition when the methylamine dosage was in the range of 0.5-4 mmol·L-1. Temperature was another important factor that affected the TCNM formation from methylamine especially in the range of 10-30℃ and the higher the temperature, the more the TCNM amount produced. The formation process of TCNM from methylamine by chlorination was in accordance with the mechanism of an electrophilic reaction, in which HClO and ClO-could be used as the electrophilic reagents to attack methylamine and then to form TCNM. |
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