Stability of newfound nitrogenous disinfection by-products haloacetamides in drinking water

Wenhai Chu, Naiyun Gao, Yang Deng

Research output: Contribution to journalArticleResearchpeer-review

35 Citations (Scopus)

Abstract

The conversion of drinking water disinfection process from free chlorine to mono-chloramine reduces the formation of trihalomethanes (THM), but increases the concentration of nitrogenous disinfection by-products (N-DBP), especially five new haloacetamides (HAcAm) including monochloroacetamide (MCAcAm), dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), monobromoacetamide (MBAcAm) and dibromoacetamide (DBAcAm). Among these HAcAms, DCAcAm and TCAcAm are normally present in drinking water at a higher concentration. The hydrolysis characteristics with different pH values and chlorination characteristics under different chlorine dosages of HAcAm were studied by combination with linear free-energy relationship (LFER). Based on the hydrolysis and chlorination characteristics of HAcAm, the reaction pathways of hydrolysis and chlorination for HAcAm were also investigated by detection of final product haloacetic acids (HAA). The results indicated that DCAcAm reacted slowly with water in highly acidic condition (pH=4) but was stable at pH 5 within 7 d reaction time. Acid environment can not cause TCAcAm hydrolysis reaction. Obvious hydrolysis reactions of DCAcAm and TCAcAm were discovered in alkaline conditions, which followed the first order reaction. The water sample containing DCAcAm and TCAcAm could be preserved by adjusting pH to 5. The use of chlorine disinfection and increment of chlorine dosage caused the amount of THM and HAA to go up in drinking water, however, it maybe resulted in the decrease of N-DBP such as HAcAm. Trichloroacetic acid (TCAA) was produced rapidly by TCAcAm hydrolysis at pH 10. For chlorination of TCAcAm, relatively stable Cl-N-TCAcAm was produced from a reaction between TCAcAm and HOC1, then continued to generate TCAA and NHCl2 at a higher concentration of HOC1.

Original languageEnglish
Pages (from-to)1569-1574
Number of pages6
JournalChinese Journal of Organic Chemistry
Volume29
Issue number10
StatePublished - 1 Dec 2009

Fingerprint

Disinfection
Drinking Water
Byproducts
Hydrolysis
Chlorination
Chlorine
Trihalomethanes
Trichloroacetic Acid
Acids
trichloroacetamide
Water
Free energy
2,2-dichloroacetamide

Keywords

  • Chlorination
  • Drinking water
  • Haloacetamide
  • Hydrolysis
  • Linear free-energy relationship
  • Nitrogenous disinfection by-product
  • Reaction pathway

Cite this

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title = "Stability of newfound nitrogenous disinfection by-products haloacetamides in drinking water",
abstract = "The conversion of drinking water disinfection process from free chlorine to mono-chloramine reduces the formation of trihalomethanes (THM), but increases the concentration of nitrogenous disinfection by-products (N-DBP), especially five new haloacetamides (HAcAm) including monochloroacetamide (MCAcAm), dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), monobromoacetamide (MBAcAm) and dibromoacetamide (DBAcAm). Among these HAcAms, DCAcAm and TCAcAm are normally present in drinking water at a higher concentration. The hydrolysis characteristics with different pH values and chlorination characteristics under different chlorine dosages of HAcAm were studied by combination with linear free-energy relationship (LFER). Based on the hydrolysis and chlorination characteristics of HAcAm, the reaction pathways of hydrolysis and chlorination for HAcAm were also investigated by detection of final product haloacetic acids (HAA). The results indicated that DCAcAm reacted slowly with water in highly acidic condition (pH=4) but was stable at pH 5 within 7 d reaction time. Acid environment can not cause TCAcAm hydrolysis reaction. Obvious hydrolysis reactions of DCAcAm and TCAcAm were discovered in alkaline conditions, which followed the first order reaction. The water sample containing DCAcAm and TCAcAm could be preserved by adjusting pH to 5. The use of chlorine disinfection and increment of chlorine dosage caused the amount of THM and HAA to go up in drinking water, however, it maybe resulted in the decrease of N-DBP such as HAcAm. Trichloroacetic acid (TCAA) was produced rapidly by TCAcAm hydrolysis at pH 10. For chlorination of TCAcAm, relatively stable Cl-N-TCAcAm was produced from a reaction between TCAcAm and HOC1, then continued to generate TCAA and NHCl2 at a higher concentration of HOC1.",
keywords = "Chlorination, Drinking water, Haloacetamide, Hydrolysis, Linear free-energy relationship, Nitrogenous disinfection by-product, Reaction pathway",
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journal = "Chinese Journal of Organic Chemistry",
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Stability of newfound nitrogenous disinfection by-products haloacetamides in drinking water. / Chu, Wenhai; Gao, Naiyun; Deng, Yang.

In: Chinese Journal of Organic Chemistry, Vol. 29, No. 10, 01.12.2009, p. 1569-1574.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Stability of newfound nitrogenous disinfection by-products haloacetamides in drinking water

AU - Chu, Wenhai

AU - Gao, Naiyun

AU - Deng, Yang

PY - 2009/12/1

Y1 - 2009/12/1

N2 - The conversion of drinking water disinfection process from free chlorine to mono-chloramine reduces the formation of trihalomethanes (THM), but increases the concentration of nitrogenous disinfection by-products (N-DBP), especially five new haloacetamides (HAcAm) including monochloroacetamide (MCAcAm), dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), monobromoacetamide (MBAcAm) and dibromoacetamide (DBAcAm). Among these HAcAms, DCAcAm and TCAcAm are normally present in drinking water at a higher concentration. The hydrolysis characteristics with different pH values and chlorination characteristics under different chlorine dosages of HAcAm were studied by combination with linear free-energy relationship (LFER). Based on the hydrolysis and chlorination characteristics of HAcAm, the reaction pathways of hydrolysis and chlorination for HAcAm were also investigated by detection of final product haloacetic acids (HAA). The results indicated that DCAcAm reacted slowly with water in highly acidic condition (pH=4) but was stable at pH 5 within 7 d reaction time. Acid environment can not cause TCAcAm hydrolysis reaction. Obvious hydrolysis reactions of DCAcAm and TCAcAm were discovered in alkaline conditions, which followed the first order reaction. The water sample containing DCAcAm and TCAcAm could be preserved by adjusting pH to 5. The use of chlorine disinfection and increment of chlorine dosage caused the amount of THM and HAA to go up in drinking water, however, it maybe resulted in the decrease of N-DBP such as HAcAm. Trichloroacetic acid (TCAA) was produced rapidly by TCAcAm hydrolysis at pH 10. For chlorination of TCAcAm, relatively stable Cl-N-TCAcAm was produced from a reaction between TCAcAm and HOC1, then continued to generate TCAA and NHCl2 at a higher concentration of HOC1.

AB - The conversion of drinking water disinfection process from free chlorine to mono-chloramine reduces the formation of trihalomethanes (THM), but increases the concentration of nitrogenous disinfection by-products (N-DBP), especially five new haloacetamides (HAcAm) including monochloroacetamide (MCAcAm), dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), monobromoacetamide (MBAcAm) and dibromoacetamide (DBAcAm). Among these HAcAms, DCAcAm and TCAcAm are normally present in drinking water at a higher concentration. The hydrolysis characteristics with different pH values and chlorination characteristics under different chlorine dosages of HAcAm were studied by combination with linear free-energy relationship (LFER). Based on the hydrolysis and chlorination characteristics of HAcAm, the reaction pathways of hydrolysis and chlorination for HAcAm were also investigated by detection of final product haloacetic acids (HAA). The results indicated that DCAcAm reacted slowly with water in highly acidic condition (pH=4) but was stable at pH 5 within 7 d reaction time. Acid environment can not cause TCAcAm hydrolysis reaction. Obvious hydrolysis reactions of DCAcAm and TCAcAm were discovered in alkaline conditions, which followed the first order reaction. The water sample containing DCAcAm and TCAcAm could be preserved by adjusting pH to 5. The use of chlorine disinfection and increment of chlorine dosage caused the amount of THM and HAA to go up in drinking water, however, it maybe resulted in the decrease of N-DBP such as HAcAm. Trichloroacetic acid (TCAA) was produced rapidly by TCAcAm hydrolysis at pH 10. For chlorination of TCAcAm, relatively stable Cl-N-TCAcAm was produced from a reaction between TCAcAm and HOC1, then continued to generate TCAA and NHCl2 at a higher concentration of HOC1.

KW - Chlorination

KW - Drinking water

KW - Haloacetamide

KW - Hydrolysis

KW - Linear free-energy relationship

KW - Nitrogenous disinfection by-product

KW - Reaction pathway

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EP - 1574

JO - Chinese Journal of Organic Chemistry

JF - Chinese Journal of Organic Chemistry

SN - 0253-2786

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