Unexpected decrease of N-Nitrosodimethylamine formation during peroxymonosulfate oxidation: The other side of bromide

Shen, Linlu; Shen, Jimin; Kang, Jing; Shen, Yang; Wang, Binyuan; Zhao, Shengxin; Gong, Yingxu; Li, Yabin; Cheng, Yizhen; Wang, Shuyu; Chen, Zhonglin

doi:10.1016/j.cej.2023.141658

Cited by 11 publications

(2 citation statements)

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“…26−28 Recent studies have found that N,N-dimethylhydrazine compounds can be transformed to NDMA by peroxymonosulfate oxidation as well. 29,30 While NDMA formation in water treatment is reasonably well understood, little attention has been paid to its formation in natural systems. Several studies have found that NDMA can be formed in the atmosphere through reactions between DMA and photochemically generated dinitrogen trioxide (N 2 O 3 ) or N 2 O 4 .…”

Section: Introductionmentioning

confidence: 99%

“…In general, NDMA yields associated with this mechanism are very low (i.e., 0.02%). However, the presence of ammonia and bromide enhances the yield by an order of magnitude (i.e., to 0.2%) by promoting the formation of the intermediates NH 2 OH and brominated UDMH. − Many pharmaceuticals that have the DMA moiety, for instance, ranitidine, metformin, and tetracyclines, follow a similar pathway to form NDMA during ozonation. − In addition, compounds with the N , N -dimethylhydrazine moiety (e.g., UDMH and daminozide), the N , N -dimethylsulfamide moiety, and the N , N -dimethylsemicarbazide moiety react readily with ozone and have extremely high NDMA yields (>50%). − Recent studies have found that N , N -dimethylhydrazine compounds can be transformed to NDMA by peroxymonosulfate oxidation as well. , …”

Section: Introductionmentioning

confidence: 99%

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Formation of N-Nitrosodimethylamine by Sunlight Irradiation of Dimethylamine Compounds in the Presence of Nitrite

Yang,

Dong,

Wang

et al. 2023

ACS EST Water

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N-Nitrosodimethylamine (NDMA) is a disinfection byproduct and a probable human carcinogen formed during water treatment processes. While its generation in engineered systems has been extensively explored, its formation in natural environments is inadequately understood. This study demonstrates that compounds with dimethylamine (DMA) functionality exposed to sunlight irradiation in the presence of nitrite (NO 2 − ) react to form NDMA. The molar yields of NDMA ranged from 0.006 to 0.035% after 6 h irradiation. The radicals generated by the photolysis of NO 2 − , notably • OH, NO • , and NO 2 •, play critical roles in this process. Three reaction pathways are involved in the NDMA formation. In the first and second pathways, nitrogen oxide radicals couple or dimerize to form the nitrosating agents N 2 O 3 and N 2 O 4 , which attack the DMA moiety, yielding NDMA. In the third pathway, the DMA moiety is oxidized by • OH via Habstraction to produce a nitrogen-centered radical (CH 3 N • CH 3 ) which, followed by the addition of a NO • , yields NDMA. Radical quenching experiments combined with theoretical calculations suggest that the • OH/H-abstraction pathway is more favorable. Given that many environmental contaminants contain DMA functionalities, the photochemical formation pathway of NDMA in the sunlit surface waters may be important for aquatic environments.

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Section: Introductionmentioning

confidence: 99%