三唑酮在水体系中的光化学降解研究

Study on photochemical degradation of triadimefon in aqueous solution

系统研究了在天然日光和高压汞灯照射下三唑酮在蒸馏水、人工海水和天然海水中的光降解情况。结果表明,天然日光照射下,三唑酮在三种介质中降解较慢。高压汞灯较天然日光能够更有效地激发三唑酮的降解,且降解符合一级动力学规律。在300 W高压汞灯照射下,三唑酮在蒸馏水、人工海水和天然海水中的半寿期分别为54.14 min、144.38 min、177.69 min。三唑酮在蒸馏水中的光降解速率大于其在天然海水中的,这主要是由于天然海水中存在的阴、阳离子和其它特殊的物质所引起的。同蒸馏水中的光反应相比,人工海水中的离子抑制了三唑酮的光降解反应。在500 W高压汞灯照射下,三唑酮的反应速率明显提高。实验发现溶液中加入重金属离子(Cu2+、Pb2+、Cd2+)能够改变三唑酮的光降解速率。

The photochemical degradation of triadimefon was systematically studied in distilled water, artificial seawater and seawater under radiation of high-pressure mercury lamp （HPML） and sunlight. The photolysis rate of triadimefon was slow in aqueous solution under sunlight. In comparison, high-pressure mercury lamp was more effective for exciting the photoreaction of triadimefon relative to sunlight and the photochemical degradation of triadimefon can be fitted with first-order kinetics. Under 300 W HPML , the half-life of photolysis of triadimefon in distilled water, artificial seawater and seawater was 54.14 min, 144.38 min and 177.69 min, respectively. The photolysis of triadimefon was faster in distilled water than in artificial seawater or natural seawater, presumably due to the existence of specific substances and ions in seawater. Compared with the case in distilled water, the ions in artificial seawater could restrain the photolysis of triadimefon. The photolysis rate of triadimefon was faster under 500 W HPML than 300 W HPML. In addition, our result showed that the addition of heavy metal ions such as Cu^2＋ .Pb^2＋ .Cd^2＋. to the three aqueous solutians could influence the photodegradatian rates of triadimefon.