Adsorption of chloroacetanilide herbicides on soil I. Structural influence of chloroacetanilide herbicide for their ads
Adsorption of chloroacetanilide herbicide acetochlor,alachlor, metolachlor and propachlor on soils and soil components was determined, and the structural differences of these herbicides were used to explain the order of sorptivity. Adsorption isotherms for all herbicide-soil combinations conformed to the Freundlich equation, and Kf increased with increasing soil organic carbon content. Kd on soil humic acid was greater than that on clay, but association of humic acid with clay reduced the overall adsorption. On all soils and soil humic acids, herbicide adsorption decreased in the order: metolachlor > acetochlor > propachlor > alachlor. On Ca2+-montmorrilonite, the order changed to metolachlor > acetochlor > alachlor > propachlor. FT-IR spectra of herbicide-clay or herbicide-humic acid-clay mixtures showed that H-bonding and charge transfer were the primary interaction pathways between these compounds and the surface of clay or humic acids. The different moieties attached to 2-chloro-acetanilide and their unique arrangement may have influenced the binding mechanisms and thus the sorptivity of these herbicides. This study indicates that the structural difference of pesticides in the same classes may be used as a molecular probe to obtain a better understanding of sorption mechanisms of pesticides on soil.
作 者： LIU Wei-ping LIU Hui-jun ZHENG Wei WANG Qi-quan LU Jian-hang 作者单位： Institute of Environmental Science, Zhejiang University at Yuquan Campus, 刊 名： 环境科学学报(英文版) ISTIC SCI 英文刊名： JOURNAL ENVIRONMENTAL SCIENCES 年，卷(期)： 2001 13(1) 分类号： X131.3 关键词：