Seid, Mingizem Gashaw Cho, Kangwoo Lee, Changha Park, Hyun-Mee Hong, Seok Won 2024-01-19T22:03:29Z 2024-01-19T22:03:29Z 2021-09-03 2018-08 0048-9697 https://pubs.kist.re.kr/handle/201004/121073 Ranitidine (RNT) has been an important tertiary amine precursor of N-nitrosodimethylamine (NDMA) in chlorine-based water treatment, due to reaction with monochloramine (NH2Cl) with exceptionally high molar yields up to 90%. This study examined the effects of nitrite ions (NO2-) on the kinetics of NDMA formation during the chloramination of RNT under variable concentrations of dissolved oxygen (DO, 0.7-7.5 mg/L), RNT (5-30 mu M), NH2Cl (5-20 mM), NO2- or NO3- (0-2 mM) and pH (5.6-8.6). In the absence of the NO2-, the ultimate molar yield of NDMA after 6 h of reaction was primarily influenced by [DO] and pH, while marginally affected by initial [RNT] and [NH2Cl]. A kinetic model, prepared in accordance with the reaction sequence of NDMA formation, suggested that the rate determining step was accelerated with increasing [NH2Cl](0), [DO], and pH. A Kinetic study together with ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometer (UPLC-Q-TOF MS) and gas chromatography (GC)/TOF MS analyses in parallel demonstrated that the nitrite ion inhibited the nucleophilic substitution of the terminal amine on NH2Cl, and reduced the pseudo-steady state concentration of N-peroxyl radicals, significantly decreasing the ultimate yields of NDMA. (c) 2018 Elsevier B.V. All rights reserved. English ELSEVIER Nitrite ion mitigates the formation of N-nitrosodimethylamine (NDMA) during chloramination of ranitidine Article 10.1016/j.scitotenv.2018.03.181 1 SCIENCE OF THE TOTAL ENVIRONMENT, v.633, pp.352 - 359 SCIENCE OF THE TOTAL ENVIRONMENT 633 352 359 N scie scopus 000432475300035 2-s2.0-85044525205 Environmental Sciences Environmental Sciences & Ecology Article PERSONAL CARE PRODUCTS WASTE-WATER TREATMENT DRINKING-WATER AQUEOUS-SOLUTION TERTIARY-AMINES ORGANIC-MATTER SURFACE WATERS KINETICS CHLORINATION PHARMACEUTICALS N-nitrosodimethylamine Ranitidine Nitrite ion Chloramination Kinetics Reaction pathway