表面活性剂和金属离子对新农药硫肟醚光解的影响

摘要

Effect of several surfactants and metal ions on photodegradation of novel insecticide sulfoxime (code: HNPC-A9908) [O-(3-phenoxybenzyl)-2-methylthio-1-(4-chloro- phenyl) propyl ketone oxime] in aqueous solutions was studied under the irradia-tion of ultraviolet light (λ 254 nm) in the laboratory. Experimental results showed that photodegradation rate of sulfoxime in the aqueous solutions varied when the insecticide suifoxime was combined with the surfaetants and inorganic salts such as ABS-Ca, castor oil polyethylene glycol ether (BY), Tween 80, ferric chloride (Fe~(3+)), cupric sulfate (Cu~(2+)) and magnesium sulfate (Mg~(2+)) at 1:1 ratio, respectively. ABS-Ca exhibited a significant photoextinction effect on photolysis of sulfoxime in aqueous solution, BY showed some photosensitized effect, and Tween80's effect varied with the illumination time, showing a photosensitization at the illumination time of less than 40 min, photoextinction after 40min illumination time. Fe~(3+) made the photolysis of sulfoxime in aqueous solution fast showing an obvious photosensitized effect, and Cu~(2+) and Mg~(2+) resulted in slow photodecomposition of sulfoxime in the aqueous solution revealing a strong photoextinction. Half-life of sulfoxime photolysis in the solutions containing ABS-Ca, BY, Tween 80, Fe~(3+), Cu~(2+) and Mg~(2+) was 21.63, 34.42, 15.29, 9.85, 43.95 and 32.20 min, respectively, and 22.3 min in the pure water without any surfactants and metal ions.%硫肟醚[O-(3-苯氧苄基)-2-甲硫基-1-(4-氯苯基)丙基酮肟醚]是我国研制成功的具有自主知识产权的一种新型杀虫剂.在室内紫外光(λ254 nm)照射下研究了几种表面活性剂和金属离子对硫肟醚在水溶液中光解的影响.试验结果表明,当土温80(Tween80)、十二烷基苯磺酸钙(ABS-Ca)、蓖麻油聚氧乙烯醚(BY)、三氯化铁(FeCl_3)、硫酸铜(CuSO_4)和无水硫酸镁(MgSO_4)分别与硫肟醚以1:1的比例混合后,硫肟醚的光解速率发生了不同程度的改变.ABS-Ca对硫肟醚在水溶液中的光解速率表现出显著的光猝灭降解效应,蓖麻油聚氧乙烯醚类表面活性剂BY对硫肟醚在水溶液中的降解表现出一定程度的光敏化作用.而吐温80对硫肟醚在水体中光解速率的影响则随照光时间而改变,当照光时间小于40 min时,表现为光敏化降解作用,大于40 min时可延缓硫肟醚的光解进程,表现出光猝灭作用.Fe~(3+)使硫肟醚在水溶液中的光解速率增快,表现出明显的光敏化降解效应,而Cu~(2+)和Mg~(2+)使硫肟醚在水体中的光解速率减慢,表现为较强的光猝灭降解作用.硫肟醚在含Tween80、ABS-Ca、BY、FeCl_3、CuSO_4和MgSO_4水溶液中的光解半衰期分别为21.63、34.42、15.29、9.85、43.95和32.20 min,而在不含任何农药化肥的纯净水中的光解半衰期为22.30 min.