水相低浓度甲氰菊酯的光降解研究

菊酯类农药的大量使用,已在环境中造成残留。文章研究了汞灯和氙灯照射下较低浓度的甲氰菊酯在水相中的光降解情况,并对降解产物进行了分析测定;研究了环境水体中典型的具有光敏作用的4种无机离子(Cu2+,NO3-,Fe3+,Mn2+)和4种有机防晒剂(2,4-二叔丁基苯酚,2,6-二叔丁基-4-甲基苯酚,2-羟基苯甲酸-2-乙基己基酯,4-甲氧基肉桂酸-2-乙基己酯)对甲氰菊酯光降解的影响;采用固相微萃取技术进行前处理,结合气相色谱、气相色谱-质谱联用检测技术进行了分析。结果表明:甲氰菊酯的光降解基本符合一级反应动力学规律,所选无机和有机光敏物质对水相中甲氰菊酯的光降解有着不同程度的影响:4-甲氧基肉桂酸-2-乙基己酯对甲氰菊酯有光抑制作用,其余3种防晒剂对甲氰菊酯光降解的影响趋势随着浓度的变化而变化;Cu2+能够抑制甲氰菊酯的光降解;而NO3-则会促进其光降解。研究结果为环境中菊酯类农药的降解消除提供理论依据。

Study on the Photochemical Degradation of Fenpropathrin of Low Concentration in Water Phase

The residue has been an indisputable fact since extensive use of pyrethroid pesticides.Photochemical degradation of fenpropathrin of low concentration was studied in the aqueous phase under the radiation of mercury lamp and xenon lamp,as well as the analysis of degradation product.Four typical photosensitive inorganic ions including Cu2+,NO3-,Fe3+,Mn2+ and four typical photosensitive organic sunscreens including 2,4-di-tert-butylphenol,2,6-di-tert-butyl-4-methylphenol,benzoic acid,2-hydroxy-,2-ethylhexyl ester,2-ethylhexyl 4-methoxycinnamate in the aquatic environment were used for showing their influence on photochemical degradation of fenpropathrin.The solid phase microextraction pre-treatment,combined with gas chromatography and gas chromatograph-mass spectrograph techniques,were applied to the research.The experimental re sults suggest that the photochemical degradation of fenpropathrin follows the fist-order kinetic law.The chosen inorganic and organic photosensitizers had varying degrees of impact on the photochemical degradation of fenpropathrin in water phase.2ethylhexyl 4-methoxycinnamate had inhibitory effect on photochemical degradation.The effects of other three sunscreens on the photochemical degradation changed with their concentration.Cu2 + had inhibitory impact on photochemical degradation,while NO3-had promoted degradation.The results provide a theoretical basis for degradation of pyrethroid pesticides in the environment.