Chlorination of humic materials: byproduct formation and chemical interpretations

Humic acid (HA) was extracted and separated into different molecular weight (MW) fractions, then coagulated by aluminum chloride and polyaluminum chloride (PACl). The removal of disinfection byproduct (DBP) precursors and the aluminum speciation variation of the coagulants were investigated in detail. In particular, the role of aluminum speciation in the removal of DBP precursors was discussed. During the coagulation process, AlCl 3 hydrolyzed into dominating in situ Al 13 species at pH 5.5. The in situ Al 13 species exhibited better removal ability for haloacetic acid (HAA) precursors than PACl. At pH 7.5, in situ hydrolyzed Al 13 species of AlCl 3 decomposed into dimeric Al species. In this case, preformed Al 13 of PACl had a high removal ability of HAA precursors. Specially, the greatest reduction of HAA precursors with a low MW (<30 kDa) was through charge neutralization at pH 5.5, and that of HAA precursors in high MW (>30 kDa) fractions was through adsorption at pH 7.5. Different from HAA precursors, the in situ Al 13 species did not have a high removal ability of trihalomethane (THM) precursors. Therefore, PACl exhibited a better removal ability of THM precursors than AlCl 3 at different pH values. In the different MW fractions, the greatest reduction of THM precursors was through charge neutralization at pH 5.5.

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“…In particular, humic substances are the principal precursors of trihalomethanes (THMs) (2) and haloacetic acids (HAAs) (3).…”

Section: Introductionmentioning

confidence: 99%

Role of Aluminum Speciation in the Removal of Disinfection Byproduct Precursors by a Coagulation Process

Zhao

Liu

et al. 2008

Environ. Sci. Technol.

124

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“…Among various DBPs, the 44 most recognized compounds are trihalomethanes (THMs) and haloacetic acids (HAAs). [2][3][4][5][6][7] In the 45 presence of bromide (Br − ), HOCl can rapidly oxidize naturally occurring Br − to hypobromous 46 acid (HOBr). 8 Upon the reaction between HOCl/HOBr and DOM, four THMs (i.e., THM4, sum 47 of CHCl 3 , CHBrCl 2 , CHBr 2 Cl, and CHBr 3 ) and nine HAAs (i.e., HAA9, sum of monochloro-, 48 dichloro-, trichloro-, monobromo-, dibromo-, bromochloro-, bromodichloro-, dibromochloro-, 49 and tribromo-acetic acids (MCAA, DCAA, TCAA, MBAA, DBAA, BCAA, BDCAA, DBCAA, 50 and TBAA, respectively)) can be formed.…”

mentioning

confidence: 99%

Formation of Bromate and Halogenated Disinfection Byproducts during Chlorination of Bromide-Containing Waters in the Presence of Dissolved Organic Matter and CuO

Liu

Croué

2015

Environ. Sci. Technol.

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Previous studies showed that significant bromate (BrO 3 − ) can be formed via the CuO-catalyzed disproportionation of hypobromous acid (HOBr) pathway. In this study, the influence of CuO on the formation of BrO 3 − and halogenated disinfection byproducts (DBPs) (e.g., trihalomethanes, THMs and haloacetic acids, HAAs) during chlorination of six dissolved organic matter (DOM) isolates was investigated. Only in the presence of slow reacting DOM (from treated Colorado River water, i.e., CRW-BF-HPO), significant BrO 3 − formation is observed, which competes with bromination of DOM (i.e., THM and HAA formation). Reactions between HOBr and 12 model compounds in the presence of CuO indicates that CuO-catalyzed HOBr disproportionation is completely inhibited by fast reacting phenols, while it predominates in the presence of practically unreactive compounds (acetone, butanol, propionic, and butyric acids). In the presence of slow reacting di-and tricarboxylic acids (oxalic, malonic, succinic, and citric acids), BrO 3 − formation varies, depending on its competition with bromoform and dibromoacetic acid formation (i.e., bromination pathway). The latter pathway can be enhanced by CuO due to the activation of HOBr. Therefore, increasing CuO dose (0−0.2 g L −1 ) in a reaction system containing chlorine, bromide, and CRW-BF-HPO enhances the formation of BrO 3 − , total THMs and HAAs. Factors including pH and initial reactant concentrations influence the DBP formation. These novel findings have implications for elevated DBP formation during transportation of chlorinated waters in copper-containing distribution systems.

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“…The formation of HKs has been associated with a higher methyl ketone content in fulvic acids 279 fractions as compared to humic acids (Reckhow et al, 1990). In our experiments, no 1,1,1-TCP 280 could be detected from any isolate.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter

2016

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Please cite this article as: Le Roux, J., Nihemaiti, M., Croué, J.-P., The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter, Water Research (2015), doi: 10.1016/j.watres.2015.10.036. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Chlorination of humic materials: byproduct formation and chemical interpretations

Cited by 641 publications

References 38 publications

Role of Aluminum Speciation in the Removal of Disinfection Byproduct Precursors by a Coagulation Process

Role of Aluminum Speciation in the Removal of Disinfection Byproduct Precursors by a Coagulation Process

Formation of Bromate and Halogenated Disinfection Byproducts during Chlorination of Bromide-Containing Waters in the Presence of Dissolved Organic Matter and CuO

The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter

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