磺酰脲类除草剂在环境中的光降解研究——水溶液中的光解动力学

Photodegradation of Sulfonylurea Herbicides ——Photolysis Kinetics in Aqueous Solution

以汞灯为光源，研究了甲黄隆、苯黄隆，氯黄隆、氯嘧黄隆、苄嘧黄隆和胺苯黄隆６种磺酰脲类除草剂在水溶液中的光解动力学．结果表明５种磺酰脲的降解呈一级动力学反应（苯黄隆除外）；体系的ｐＨ值对降解速率影响不明显，光强的影响较明显；Ｈ２Ｏ２、丙酮和溶解有机质（ＤＯＭ）均可促进磺酰脲光解；溶解氧对该类除草剂光解的影响表现为光氧化与光淬灭２种作用的竞争．

The photodegradation kinetics of six sulfonylurea herbicides,which are metsulfuron methyl,chlorsulfuron,tribennuron,chlorimuron,bensulfuron,and DPX A7881,has been studied in aqueous solution by irradiation of mercury lamps.The primary degradation of each herbicide except for tribenuron follows a pseudo first order kinetics.The pH of the reaction buffers has shown little effect on the photolysis of these compounds,while the presence of hydrogen peroxide,acetone and dissolved organic matter (DOM) as well as the enhancement of irradiation intensity could accelerate the photoreactions of these herbicides.It is considered that dissolved oxygen has a competitive effect of photooxidation and quenching on the phtodegradation of sulfonylurea herbicides.