DOI: 10.1016/j.watres.2018.12.002
Scopus记录号: 2-s2.0-85058508116
论文题名: Lower molecular weight fractions of PolyDADMAC coagulants disproportionately contribute to N-nitrosodimethylamine formation during water treatment
作者: An D. ; Chen Y. ; Gu B. ; Westerhoff P. ; Hanigan D. ; Herckes P. ; Fischer N. ; Donovan S. ; Croue J.P. ; Atkinson A.
刊名: Water Research
ISSN: 431354
出版年: 2019
起始页码: 466
结束页码: 472
语种: 英语
英文关键词: Chloramination
; N-nitrosodimethylamine
; Nuclear magnetic resonance
; polyDADMAC
; Size fractionation
Scopus关键词: Amines
; Chlorine compounds
; Coagulation
; Molecular weight
; Nuclear magnetic resonance
; Nuclear magnetic resonance spectroscopy
; Polymers
; Reaction intermediates
; Water distribution systems
; Water treatment
; Chloramination
; Disinfection by-product
; Molecular weight fraction
; N-nitrosodimethylamine
; polyDADMAC
; Polydiallyldimethyl ammonium chloride
; Polymer manufacturers
; Size fractionation
; Amination
; chloramine derivative
; coagulating agent
; dimethylamine
; dimethylnitrosamine
; polymer
; water
; byproduct
; cation
; chemical reaction
; coagulation
; disinfection
; drinking water
; experiment
; fractionation
; nuclear magnetic resonance
; organic nitrogen compound
; polymer
; reaction kinetics
; turbidity
; water treatment
; Article
; carbon nuclear magnetic resonance
; chemical structure
; diffusion
; molecular weight
; particle size
; priority journal
; proton nuclear magnetic resonance
; sedimentation
; water treatment
英文摘要: N-nitrosodimethylamine (NDMA) is a chloramine disinfection by-product, and its formation in drinking waters can increase due to the addition of cationic polydiallyldimethylammonium chloride (polyDADMAC). PolyDADMAC is a cationic polymer added as a coagulant or coagulant aid to enhance turbidity removal during sedimentation and filtration. This paper answers two central questions to understanding the nature of the NDMA precursors in polyDADMAC. First, what is the reactivity of different molecular weight (MW) fractions of polyDADMAC with chloramines? NDMA formation potential (NDMAFP) and kinetic experiments with chloramines were conducted for non-fractionated (raw) and size-excluded fractions (<3K, 3–10K, and >10K Da.) of polyDADMAC. The lower MW fraction (<3K Da.) of polyDADMAC solutions was responsible for forming 64 ± 6% of the NDMA, despite containing only 8.7 and 9.8% of the carbon or nitrogen present in the bulk polymer. The chloramine demand kinetics of the lowest MW fraction were also >2× faster than the higher MW fractions. Therefore, in a water treatment application the lower MW polyDADMAC likely contributes to most of the NDMA attributed to the use of polyDADMAC. The second question was: can 1 H and 13 C nuclear magnetic resonance spectroscopy (NMR) be used to characterize the molecular structures in polyDADMAC that react with chloramines? A peak for 1 H NMR dimethylamine (DMA), a known low MW NDMA precursor, was found in a commercial polyDADMAC solution and decreased upon chloramination. The estimated DMA alone could not account for the observed NDMAFP, indicating the presence of other low MW precursors. Diffusion order spectroscopy (DOSY) NMR also showed multiple lower MW organics in polyDADMAC that change upon chloramination, including a 1.5× decrease in MW, suggesting chloramines cleave C–C or C–N bonds. These reactions may produce intermediates responsible for NDMA formation. Polymer manufacturers could use NMR to synthesize polyDADMAC with less DMA and other low MW compounds that produce NDMA upon chloramination. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122076
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, China; School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ 85287-5306, United States; Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557-0258, United States; School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, United States; Curtin Water Quality Research Centre, Curtin University, Perth, WA, Australia; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
Recommended Citation:
An D.,Chen Y.,Gu B.,et al. Lower molecular weight fractions of PolyDADMAC coagulants disproportionately contribute to N-nitrosodimethylamine formation during water treatment[J]. Water Research,2019-01-01