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Updated: Jun 20, 2026

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method
Published on: December 25, 2016
Nitrite formation during low pressure ultraviolet lamp irradiation of nitrate
Ning Lu1, Nai-Yun Gao, Yang Deng
1State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
Abstract:
During ultraviolet light (UV) disinfection, nitrate (NO3-) present in raw water may transform to nitrite (NO2-) that can cause serious human diseases. In this study, the formation of NO2- from NO3- was studied at different experimental conditions under the irradiation of a low-pressure ultraviolet (LPUV) lamp at 253.9 nm. The investigated experimental variables included initial NO3- concentration, solution pH (6.2-9.5), and hydrogen peroxide (H2O2) dose (0-25 mg L(-1)). Moreover, the effect of titanium dioxide (TiO2) was determined. Results showed that the formation of NO2- was enhanced at a high initial NO3- concentration and a high pH, but was inhibited, to some different degrees, by introduction of H2O2 or photocatalyst TiO2. The effect of pH on NO2- formation was probably due to the impact of hydrogen ion on the stability of several intermediates such as peroxynitrite (ONOO-), N2O3, and N2O4. And the inhibiting effects of H2O2 and TiO2 were attributable to production of additional hydroxyl radical (OH) that scavenged NO2-. At pH 9.5 and an initial NO3- concentration of 10 mg L(-1) NO3--N, the concentration of NO2- produced was above 0.1 mg L(-1) NO2--N, the Germany drinking water standard. When 25 mg L(-1) H2O2 was added, the NO2- level was decreased below the standard.
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