几种物质对苯噻草胺在水中光降解的影响

高压汞灯下不同物质对水中的苯噻草胺光化学降解的影响研究表明，NO₂^-和NO₃^-对苯噻草胺的光解有猝灭作用，其中NO₃^-在10∶1的添加浓度(质量浓度)下猝灭作用最明显，照光15 min猝灭率达53.3%；卤素离子对苯噻草胺光解有重原子猝灭效应，作用最强的是添加10∶1的I^-(质量浓度)，照光15 min 猝灭率达76.9%；4种表面活性剂随添加浓度的增大对苯噻草胺光解的阻滞作用增强，除农乳404在较低添加浓度下(质量浓度比1∶5和1∶1)对苯噻草胺的光解表现出微弱的敏化效应外，其余均表现为猝灭作用；4种除草剂(杀草丹、苄嘧磺隆、甲草胺和绿磺隆)中，只有苄嘧磺隆在低添加浓度(质量浓度比1∶10)时对苯噻草胺有光敏化作用，照光25 min光敏率为18.2%，其余除草剂各添加浓度下均对苯噻草胺表现出光猝灭作用；充氮气10 min，苯噻草胺的光解半衰期由不充氮气的7.14 min缩短为6.70 min.

Effects of dissolved compounds on photodegradation of mefenacet in water

The study with high-pressure mercury lamp illuminating showed that after illuminated for 15 min, NO2- and NO3- quenched the photolysis of mefenacet, and NO3- with a concentration ratio 10:1 (mass) had the most obvious effect, its quenching rate being up to 53.3%. Halogen ions inhibited the photolysis of mefenacet by "weight atom effect". When the concentration ratio of I- was 10:1, the quenching rate was 76.9% after illuminated for 15 min. Surfactants Nongru 500, Nongru 404, Nongru 601 and Nongru 603 had different effects on the photodegradation of mefenacet. At concentration ratios 1:5 and 1:1, only Nongru 404 showed a weak photosensitive effect, while in the other cases, all the four surfactants had photoquenching effects. Among the four herbicides benthiocarb, bensulfuron, alachlor and chlorsulfuron, only bensulfuron at low concentration ratio (1 : 10) accelerated the photolysis of mefenacet, with a photosensitive proportion of 18.2% after illuminated for 25 min. Aerified N2 could accelerate the photolysis of mefenacet, and the half-life was shortened from 7.14 min to 6.70 min without aerifying N2.