[Photochemical reaction types of the azole fungicide fluconazole under UV-vis irradiation].

This study selected the azole fungicide fluconazole as a model compound,and investigated its photodegradation kinetics and photoreaction types in pure water.It was found that under UV-vis irradiation(λ200 nm),the fluconazole photodegraded fast and followed the pseudo-first-order kinetics,whereas under simulated sunlight(λ290 nm),photodegradation did not occur.The ROS scavenging experiments and competition kinetic examination indicated that the compound underwent both direct photolysis and self-sensitized photooxidation via ·OH other than1 O2.The bimolecular rate constant for the reaction between fluconazole and ·OH was(5.95±0.58)×109 L·(mol·s)-1,and the corresponding environmental half-life was calculated to be(32.41±3.16) h in surface waters.Furthermore,it was deduced from the photodegradation product identification that the UV-vis degradation pathways involved photoinduced defluorination,hydrolysis and photooxidation.