UV Direct Photolysis of N-Nitrosodimethylamine (NDMA): Kinetic and Product Study

Abstract

Dedicated to Professor Andre¬ M. Braun on the occasion of his 60th birthdayThe ultraviolet (UV) direct photolysis of N-nitrosodimethylamine (NDMA) in aqueous solutions at pH 3 and 7 leads to dimethylamine, and nitrite and nitrate ions as the major degradation products. In addition, small amounts of formaldehyde, formic acid, and methylamine are formed. When the initial concentration of NDMA was 1 mm, only a 13% decrease in the total organic carbon (TOC) was measured at pH 7, whereas no significant change in the TOC was observed at pH 3. In the concentration range 0.01 ± 1 mm NDMA, zero-order kinetics is obeyed, whereas first-order kinetics is followed at concentrations below 0.01 mm. The photolysis occurs much faster at pH 3 than at pH 7, which is explained by the difference in the quantum yields of the process at these two pH values. UV Direct photolysis is an efficient process for the removal of NDMA from contaminated waters, and electrical energy per order (E EO ) values as low as 0.3 ± 0.5 kWh/order/m 3 were calculated for treatment of low concentrations of NDMA (0.001 mm).

Formation and Destruction of NDELA in 30 wt% MEA (Monoethanolamine) and 50 wt% DEA (Diethanolamine) Solutions

“…Nitrate and nitrite have been reported in literature to be formed under NDMA photodegradation in weakly acidic water solution (Plumlee and Reinhard, 2007). However literature findings also suggest that in alkaline solutions, other inorganic nitrogen products than nitrate and nitrite like N 2 and N 2 O are formed (Xu et al, 2009a;Stefan and Bolton, 2002).…”

Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China

“…Several alternative disinfectants such as O 3 are able to produce nitrosamines, but usually at lower concentrations than chloramines (Najm and Trussell, 2001;Andrzejewski et al, 2008). In contrast, UV and advanced oxidation processes have both been investigated as possible strategies to decrease or eliminate nitrosamine in water (Stefan and Bolton, 2002;Lee et al, 2005;Landsman et al, 2007). In fact, NDMA levels of P5 decreased to 3.5 ng/L in finished water after LPUV/OCl − treatment.…”

Mutagenicity and NO Formation from UVA Irradiated N-Nitrosoproline, and Characterization of Photoproduct Formed in UVA-irradiated Mixture of N-Nitrosoproline with 2^|^prime;-Deoxyguanosine in Neutral Solution

“…UVA-photolysis of NPRO and NO production was observed in both aqueous and nonaqueous NPRO solutions. Although photo-elimination of NO radical from N-nitrosodimethylamine was stimulated by hydrogen bonding under acidic aqueous conditions (25), N-nitroso-a-amino acids may participate in intramolecular hydrogen bonding (17). The photo-induced elimination of nitric oxide from NPRO dissolved in methanol and acetonitrile may progress via intramolecular hydrogen bonding between the N-nitroso and carboxy moieties.…”