混合农药对氟乐灵在固相表面光化学降解影响的研究

Effects of Selected Pesticides on Photodegradation of Trifluralin on Solid Phase

以高压汞灯和太阳光为光源,研究氟乐灵在玻片、硅胶G、石英砂和膨润土表面的光化学降解。结果表明,在高压汞灯下,氟乐灵在玻片、硅胶G、石英砂和膨润土表面的光解半衰期分别为24.78、98.51、106.41和220.42 m in。将7种农药分别与氟乐灵在硅胶G中以1∶1混合,经太阳光照射,混合农药对氟乐灵均表现光敏化作用;剂量比为10∶1时,表现为光猝灭效应;而1∶5时,溴氰菊酯和氟氰菊酯仍为光猝灭作用,其余5种农药则表现为光敏化作用。在石英砂表面,丙烯菊酯使氟乐灵光解半衰期延长,氰戊菊酯则使氟乐灵在膨润土表面光稳定性增强,照光18 h后,氟乐灵单独处理降解率为27.05%,而与氰戊菊酯共存时,氟乐灵仅降解了5.41%。

The photodegradation of trifluralin was investigated on solid phase, under high pressure mercury lamp or sunlight irradiation. The half-lives of trifluralin adsorbed on glass, silica gel, quartz sand and bentonite under HPML were 24.78 min, 98.51 min, 106.41 min and 220.42 min, respectively. The effects of selected pesticides on photolysis of trifluralin on solid phase were also studied. The result showed that the photolytic rate of trifluralin was accelerated by pyrethroids or butachlor at the dosage ratio of 1 ： 1 on silica gel under sunlight, while it was delayed by pyrethroids or butachlor at the dosage ratio of 10 ： 1. Photostabilization was observed when trifluralin mixed with dehamethrin or bifenthrin at the dosage ratio of 5 ： 1. The photodegradation of trifluralin was delayed by allethrin on quartz sand or fenvalerate on bentonite.