Nitrite and nitrate induced photodegradation of monolinuron in aqueous solution

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 NO3 − and NO2 − as photoinducers, hydroxyphenyl-substituted photodegradation products were found to be formed specifically through the involvement of OH° radicals. NO− and NO2-phenyl substituted compounds were also observed as a result of the production of NO° and NO2° radicals. Half-lives of monolinuron in aqueous solutions were measured in various conditions of concentrations of substrate and inducer, oxygen content and pH.