Nitrite and nitrate induced photodegradation of monolinuron in aqueous solution

Abstract

Here we evidenced the photo-induced degradation of monolinuron, a phenylurea herbicide, through the 300-450 nm light excitation of nitrite and nitrate species. The degradation pathways were compared to those obtained under direct photolysis at 254 nm. When using NO 3 and NO 2 as photoinducers, hydroxyphenylsubstituted photodegradation products were found to be formed specifically through the involvement of OH radicals. NO and NO 2 -phenyl substituted compounds were also observed as a result of the production of NO and NO 2 radicals. Half-lives of monolinuron in aqueous solutions were measured in various conditions of concentrations of substrate and inducer, oxygen content and pH.

Preliminary Study of the Photolysis of Fluorene in Rainwater

“…In a spiked rain solution, it is believed that photolysis is greatly enhanced by the existence of these species. Nitrates and nitrites can produce hydroxyl radicals after excitation by solar ultraviolet light (Nelieu et al 2004). Photo-Fenton reaction involving hydrogen peroxide and iron (III)-organic ligand complex gave a significant contribution to OH radical formation in the rainwater collected at our sampling site (Nakatani et al 2007).…”

Photoenhanced transformation of nicotine in aquatic environments: Involvement of naturally occurring radical sources

“…Involvement of nitrogen-centered radicals in the photochemical transformation of Nico is supported by the detection of nitroderivatives as transformation intermediates upon irradiation of nitrite. The formation of nitroderivatives by irradiation of xenobiotics in presence of nitrite and nitrate has been previously observed (Shankar et al, 2007) and the formation of NO-and NO 2 -phenyl substituted compounds was explained by reaction with NO • and NO 2 • (Nélieu et al, 2004).…”

Occurrence and Fate of Selected Endocrine-Disrupting Chemicals in Water and Sediment from an Urban Lake

“…DOM can promote the photodegradation by photo-inducing free radicals such as hydroxyl radicals (OHÁ), peroxyl radicals (ROOÁ), and singlet oxygen ( 1 O 2 ) (Chowdhury et al 2011). NO 3 -can also produce OHÁ when excited by UV light at a wavelength between 290 and 330 nm (Nélieu et al 2004).…”