Formation of NDMA from ranitidine and sumatriptan: The role of pH

Shen, Ruqiao; Andrews, Susan A.

doi:10.1016/j.watres.2012.11.004

Cited by 57 publications

(29 citation statements)

References 25 publications

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“…All of the above results indicate that our theoretical data are in good agreement with experimental results. 1−3,9,10,19 This also indicates that there is a good relationship between the activation energy of a Step 4 and formation of NDMA for aromatic tertiary amines; thus, the nitrosation of various aromatic tertiary amines by NO + appears to be important for NDMA formation.…”

Section: Resultsmentioning

confidence: 92%

“…However, in Step 4, the Δ G ⧧ of TMA is much higher than that of R-Model by around 43 and 35 kcal/mol in the gas phase and water, respectively. Such a notable difference in the activation free energy can explain the experimental results 1−4,9,10,19,37 that the yield of NDMA from ranitidine is much higher (>60%) than that from TMA (∼2%), and only Step 4 was found to correlate to NDMA formation. Further studies demonstrated that this can be also attributed to the different stabilities of furan-2-ylmethylium and methylium cations.…”

Section: Resultsmentioning

confidence: 97%

“…Unfortunately, chloramination has been associated with the formation of N -nitrosamines. 1−10 Over the past decade, there has been great interest in the investigation of N -nitrosamines formation in drinking water treatment because many of them are carcinogenic, mutagenic, and teratogenic. 1−20 In particular, N -nitrosodimethylamine (NDMA), which has the simplest structure and is the most commonly detected N -nitrosamine, has been demonstrated to be a potent carcinogen.…”

Section: Introductionmentioning

confidence: 99%

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Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

Liu

Selbes

Zeng

et al. 2014

Environ. Sci. Technol.

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Chloramination of drinking waters has been associated with N-nitrosodimethylamine (NDMA) formation as a disinfection byproduct. NDMA is classified as a probable carcinogen and thus its formation during chloramination has recently become the focus of considerable research interest. In this study, the formation mechanisms of NDMA from ranitidine and trimethylamine (TMA), as models of tertiary amines, during chloramination were investigated by using density functional theory (DFT). A new four-step formation pathway of NDMA was proposed involving nucleophilic substitution by chloramine, oxidation, and dehydration followed by nitrosation. The results suggested that nitrosation reaction is the rate-limiting step and determines the NDMA yield for tertiary amines. When 45 other tertiary amines were examined, the proposed mechanism was found to be more applicable to aromatic tertiary amines, and there may be still some additional factors or pathways that need to be considered for aliphatic tertiary amines. The heterolytic ONN(Me)2–R+ bond dissociation energy to release NDMA and carbocation R+ was found to be a criterion for evaluating the reactivity of aromatic tertiary amines. A structure–activity study indicates that tertiary amines with benzyl, aromatic heterocyclic ring, and diene-substituted methenyl adjacent to the DMA moiety are potentially significant NDMA precursors. The findings of this study are helpful for understanding NDMA formation mechanism and predicting NDMA yield of a precursor.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

Liu

Selbes

Zeng

et al. 2014

Environ. Sci. Technol.

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“…Other identified potential NDMA precursors are: tertiary and quaternary amines containing DMA functional groups, [17][18][19][20] natural organic matter, [21] polyelectrolytes and ion-exchange resins, [22,23] fungicides, pesticides, and herbicides, [24,25] pharmaceuticals and cosmetics. [26,27] Among these NDMA precursors, tertiary amines usually have higher NDMA formation potential. [20,22,28] The occurrence and fate of NDMA and its potential precursors in wastewater treatment plants (WWTPs) have been investigated.…”

Section: Introductionmentioning

confidence: 99%

Degradation of typical N-nitrosodimethylamine (NDMA) precursors and its formation potential in anoxic-aerobic (AO) activated sludge system

Wang

2014

Journal of Environmental Science and Health, Part A

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N-nitrosodimethylamine (NDMA) is an emerging disinfection byproduct. Removal of its potential precursors is considered as an effective method to control NDMA. In this study, four typical NDMA precursors (dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB)) were selected, and their removal capacities by activated sludge were investigated. Batch experiments indicated that removal of NDMA precursors was better under aerobic condition than anoxic condition; and their specific degradation rates follow the order of DMA > TMA > DMFA > DMAB. In anoxic-aerobic (AO) activated sludge system, the optimal hydraulic retention time and sludge retention time were 10 h and 20 d, respectively, for the removal of both NDMA precursors (four selected NDMA precursors and NDMA formation potential (NDMA FP)) and nutrients. Our results also suggested that there was a positive correlation between NDMA FP and dissolved organic nitrogen (DON) in wastewater. The removal efficiency of NDMA FP was in the range of 46.8-72.5% in the four surveyed wastewater treatment plants except the one which adopted chemically enhanced primary process. The results revealed that the AO system had the advantage of removing NDMA FP. Our results are helpful for the knowledge of the removals of NDMA precursors during activated sludge treatment processes.

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“…It is ubiquitous in natural waters and wastewaters, but its concentration and NDMA yield cannot account for all the NDMA precursors detected in water samples. Other identified potential NDMA precursors are as follows: tertiary and quaternary amines containing DMA functional groups, natural organic matter, polyelectrolytes and ion‐exchange resins, fungicides, pesticides, and herbicides, pharmaceuticals and cosmetics . Among these NDMA precursors, tertiary amines usually have higher NDMA formation potential …”

Section: Introductionmentioning

confidence: 99%

Degradation of dimethylamine and three tertiary amines by activated sludge and isolated strains

Wang

2014

J of Chemical Tech & Biotech

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BACKGROUND N‐nitrosodimethylamine (NDMA) is an emerging disinfection byproduct. The effective and economical method to control NDMA is to remove its potential NDMA precursors. In this study, experiments were conducted to investigate the removals of four typical NDMA precursors (dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB)) by activated sludge and isolated strains. RESULTS Batch experiments indicated that the specific degradation rates of the four NDMA precursors follow the order DMA > TMA > DMFA > DMAB; and under different redox conditions, follow the order aerobic > anoxic > anaerobic. In an anaerobic–anoxic–aerobic activated sludge system, the optimal hydraulic retention time (HRT) and sludge retention time (SRT) were 10 h and 20 days, respectively, for the removals of both NDMA precursors and nutrients. Bacterial strains were isolated from aerobic activated sludge and identified based on 16S rDNA sequence analysis. A pH of 8–9 and temperature of 30–35°C were optimal for the removal of the four NDMA precursors by the isolated strains. Degradation of the four NDMA precursors by the isolated strains were fitted well by the Haldane model. CONCLUSION These results are helpful for knowledge of the removals of NDMA precursors during activated sludge treatment processes. © 2014 Society of Chemical Industry

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Formation of NDMA from ranitidine and sumatriptan: The role of pH

Cited by 57 publications

References 25 publications

Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

Degradation of typical N-nitrosodimethylamine (NDMA) precursors and its formation potential in anoxic-aerobic (AO) activated sludge system

Degradation of dimethylamine and three tertiary amines by activated sludge and isolated strains

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