有机膨润土辛硫磷缓释剂的制备和释放研究

Controlled release of phoxim from organobentonite based formulation

使用缓释剂是减少农药对环境污染的有效策略。为开发成本低廉且具有释放速度调节能力的农药缓释剂,以十六烷基三甲基氯化铵(HTMAC)为改性剂制备的有机膨润土作为辛硫磷的载体,制备辛硫磷缓释颗粒剂,分析在水中辛硫磷颗粒剂的释放行为。结果显示,HTMAC改性有机膨润土对辛硫磷具有良好的吸附性能,其吸附量最高可达0.966 g/g膨润土。有机膨润土极大延缓了辛硫磷的释放速率,控制季铵盐的用量可以在一定程度上调节辛硫磷的释放速率,50%辛硫磷活性成分从改性剂用量为50%、100%和150%可交换阳离子容量的有机膨润土颗粒剂的释放时间T50分别为普通颗粒剂的3.4倍、10.4倍和10.1倍。

The release of pesticide from the controlled release formulation is the best strategy to re duce the agroenvironmental pollution. To obtain a controlled release formulation of low cost and of release regulation capability, organobentonite was prepared by employing hexadecyl trimethyl ammo nium chloride （HTMAC） as modifier and used as cartier of phoxim. Organobentonite incorporating phoxim was used to obtain controlled release granule and the release behavior of phoxim was studied in water. The organobentonite exhibited excellent sorption capacity for phoxim, reaching a maximum of 0. 966 g/g organobentonite. The results indicated that organobentonite greatly reduced the release of phoxim and suggested the feasibility of regulating the release of phoxim via controlling the amount of organic modifying agent. The time taken for 50% of active ingredient to be released, T5o, from the formulation based on organobentonite with HTMAC loading of 50% , 100% and 150% of the cation exchange capacity were found to be 3.4, 10. 4, and 10. 1 folds of that from the conventional formulation.