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UV Direct Photolysis of N ‐Nitrosodimethylamine (NDMA): Kinetic and Product Study
Author(s) -
Stefan Mihaela I.,
Bolton James R.
Publication year - 2002
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(200205)85:5<1416::aid-hlca1416>3.0.co;2-i
Subject(s) - chemistry , dimethylamine , n nitrosodimethylamine , photodissociation , formaldehyde , methylamine , nitrite , aqueous solution , kinetics , nitrate , formic acid , inorganic chemistry , environmental chemistry , photochemistry , chromatography , organic chemistry , carcinogen , physics , quantum mechanics
The 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 m M , 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 m M NDMA, zero‐order kinetics is obeyed, whereas first‐order kinetics is followed at concentrations below 0.01 m M . 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 m M ).