Degradation and fate of N-nitrosamines in water by UV photolysis

Carcinogenic nitrosamines have received much attention due to their formation in CO₂ capture processes and probable emission into the atmosphere. Fortunately, nitrosamines are decomposed by exposure to UV irradiation. This may be an effective strategy to degrade nitrosamines, forming more benign products in the process. In this work, UV photolysis was used to examine the degradation kinetics and fate of nitrosamines (i.e., N-nitrosodiethylamine (NDEA), N-nitrosodibutylamine (NDBA), N-nitrosodimethylamine (NDMA), N-nitrosodiethanolamine (NDELA), and N-nitrosopyrrolidine (NPYR)) in water at 40°C. Nearly all nitrosamines were decomposed within the first 10 min of photodegradation using 4 W, low pressure Hg lamp. Pseudo-first order reaction rate constants were 1.8 × 10^-2, 2.6 × 10^-2, 2.6 × 10^-2, 2.3 × 10^-2, and 1.4 × 10^-2 L/W-min for NDEA, NDBA, NDMA, NDELA, and NPYR, respectively. There was minimal change in total organic carbon (TOC) and total nitrogen (TN), suggesting negligible loss of nitrosamines and photodegradation products by evaporation.