除草剂咪草烟在土壤上吸附-脱附过程及作用机理

ADSORPTION-DESORPTION PROCESS AND INTERACTION MECHANISM OF HERBICIDE IMAZETHAPYR WITH SOILS

本文研究了咪唑琳酮类除草剂咪草烟（Imazethapyr）在不同土壤固-液相间的分配及与土壤组分作用的定量相关性。结论指出：咪草烟在土壤固-液相的分配主要受土壤粘粒、有机质及土壤pH的影响。它们在土壤上的吸附-脱附均可用Freundlich方程描述；通过运用红外及X-衍射技术，从分子水平研究了咪草烟与蒙脱石的作用机理，发现咪草烟与蒙脱石的作用不仅发生在表面，而且咪草烟还能进入蒙脱石内层与其层间阳离子形成配合物。

The adsorption and desorption of the herbicide imazethapyr, (RS)-5-ethyl-2-(4 -isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) nicotinic acid, on various soils were studied. Adsorption isotherms conformed to Freundlich equation The K, values increased with increasing organic carbon content of the soils. On the other hand, the behavior of imazethapyr in the soil is strongly affected by pH and clay content. As pH decreased, imazethapyr was more strongly absorbed, reducing its mobility and plant availability. Desorption isotherms also conformed to Freundlich equation, but Kdes values were higher than those of adsorption and increased with increase in the concentration of initially adsorbed imazethapyr. Through preparing the homoionic Na+-, Ca2+-, Cu2+-, and Al3+-saturtated clay self-carrier membrane and using FT-IR, we studied the interaction mechanism of imazethapyr with the clay mineral. The results of X-ray diffraction also revealed that imazethapyr can enter the inner layer of bentonites and form complexes with the interlayer cations.