Comparison of monuron and isoproturon photodegradation processes in absence and in the presence of nitrate and nitrite in aqueous solution

Abstract-The photodegradation of two phenylurea herbicides monuron 3-(4-chloropylphenyl)-1,1 dimethylurea) and isoproturon (3-(4isopropylphenyl)-1,1 dimethylurea) in an aqueous solutions containing nitrates (10 M) and nitrites (10 M), using irradiation at 310 nm and at 365 nm respectively is investigated. In both cases MN (10 M) and IP (10 M) photodegradation followed pseudo-first order kinetics. The kinetics of monuron and isoproturon are accelerated in the presence of nitrates and nitrites. The major photodecomposition products from IP photolysis are detected through GC–MS, formed mainly through oxidation of the N-terminus group, deisopropylation are observed with isoproturon. Hydroxylation of the phenyl ring is observed with two herbicides.