三唑酮的光化学降解研究

以太阳光和高压汞灯为光源研究了三唑酮在溶液相中的光化学降解。结果表明,在太阳光下,三唑酮在正己烷、甲醇、丙酮和纯水中均能较稳定存在;高压汞灯下熏三唑酮光降解速度很快,有机溶剂中降解快慢顺序是丙酮>甲醇>正己烷,水溶液中三唑酮的光解率与其初始浓度呈负相关关系,各种类型水中光降解速率顺序为纯水>井水>河水>池塘水。

Photolysis of Triadimefon in Solvents and Aquatic Solutions

The Photolysis of pesticides triadimefon {1-(4-chlorophenoxy)-3, 3-dimethyl-1-(1H-1,2,4-triazol-1-yl) butanone} was studied under sunlight and high pressure mercury lamp(HPML) in solvents and aquatic solutions. The analyses were conducted both for irradiated samples and control solutions that kept in the dark during irradiation. Triadimefon showed no sign of degradation under control treatment and the photodegradation kinetics was strongly dependent on the solvent and on the irradiation wavelength. Triadimefon was stable in organic and aquatic solutions under sunlight, while, the photolytic rate of triadimefon was very high under HPML. The photolytic rates of traidimefon in different organic solvents and aquatic solutions showed the following sequences: acetone>methanol>hexane, pure water>well water>river water>pond water. The results agreed with the higher degradation quantum yields of triadimefon obtained in aqueous solution and confirmed that the main degradation pathways were solvent dependent. Direct photoreaction was an important dissipation pathway of triadimefon in natural water systems and the water content which included dissolved organic and inorganic matrix affected the behavior of triadimefon in different natural water systems. The photolytic rate was negatively correlated to the dosage in aquatic solution. The photochemical studies on pesticides and other pollutants should be carried out in conditions as similar as possible to those observed in environmental systems.