克螨特和霸螨灵及其混剂在水中的光降解

研究了克螨特、霸螨灵在几种水体中的光降解以及 2种农药之间的光敏化或光猝灭效应。结果表明 ,在 3 0 0W高压汞灯光照处理时 (试验试管距光源 8cm) ,克螨特和霸螨灵都极易降解 ,克螨特的光解半衰期为 9.0 6min ,霸螨灵的光解半衰期仅为 1 .4 8min。克螨特在不同水体中的光解率为 :重蒸馏水 >鱼塘水 >河水 >井水 ,霸螨灵的光解率为 :井水 >重蒸馏水 >鱼塘水 >河水 ;2种农药在现采水、过滤水、灭菌水中的光解率依次降低。克螨特和霸螨灵混剂在重蒸馏水中互为光猝灭剂 ,在井水、河水和塘水中霸螨灵对克螨特有极显著的光敏化作用 ,而克螨特对霸螨灵有极显著的光猝灭效应。克螨特、霸螨灵在pH 5和 pH 9缓冲液中光解率比之在 pH 7缓冲液中稍快 ,光猝灭效应也较强烈。在重蒸馏水中太阳光照处理时 ,克螨特和霸螨灵互为光敏剂 ,而高压汞灯下则互为光猝灭剂。

Photodegradation of propargite,fenpyroximate and their mixture in water

Photodegradation of propargite and fenpyroximate and their photoactivating and photoquenching effects on each other in water were studied.Under the illumination of a 300 W high pressure mercury vapor lamp,the half-life of propargite was 9.06 minutes and that of fenpyroximate 1.48 minutes.The photolytic rates of propargite were in a decreasing order of redistilled water>pond water>river water>well water;and of fenpyroximate in the order of well water>redistilled water>pond water>river water;The photolytic rates of the two pesticides were both in the order of sampled water>filtered (water>)sterilized water.There were significant photoactivating and photoquenching effects on photodegradation of each other and these effects were different in different sorts of water,and under different illuminating lights.It was observed that the photolytic rates of the two pesticides were quicker in pH 5 and pH 9 phosphate buffers than in pH 7 phosphate buffer,and so were the photoquenching effects.In redistilled water under sunlight propargite and fenpyroximate were photoactivator to each other,whereas under a 300 W high pressure mercury vapor lamp they were photoquencher to each other.