异丙甲草胺在不同类型土壤中的吸附和淋溶特性研究

Adsorption and Leaching Behavior of Metolachlor in Different Soils

【目的】研究异丙甲草胺在甘蔗种植区3种代表性土壤中的吸附和淋溶特性。【方法】采用批量平衡法和土柱淋溶法,研究其在不同土壤中的吸附淋溶特性。【结果】异丙甲草胺在广西来宾壤土、扶绥壤质粘土和安徽萧县粉砂质壤土中的吸附规律均可以用Freundlich方程较好描述,土壤有机碳归一化吸附系数(KOC)分别为75.71、35.80和34.93,吸附常数(Kf)分别为7.58、3.06、3.12;表明异丙甲草胺在壤土中较难吸附,在另两种土壤中属难吸附;吸附自由能(△G)为-10.73、-8.87、-8.81 KJ/mol,均属于物理吸附;【结论】异丙甲草胺在粉砂质壤土中可淋溶,在壤土和壤质黏土中为较难淋溶,其在粉砂质壤土中移动性较壤质粘土和壤土强,对地下水造成污染的可能性较大。

【Objective】The adsorption and leaching behavior of metolachlor in different soils were studied.【Method】The adsorption and leaching of metolachlor in different soils were conducted by batch equilibrium and column leaching experiments.【Result】The adsorption of metolachlor in the tested soils was better fitted by the empirical Freundlich adsorption isotherm,and the adsorption constants（ Kf） in Guangxi loam soil,Guangxi loamy clay、Anhui sandy loam were 7. 58,3. 06 and 3. 12. The organic carbon partition coefficients（ KOC） were 75. 71、35. 80 and 34. 93,which demonstrated that metolachlor was rather difficult to be adsorbed on the loam soil,the sorption on the loamy clay and sandy loam were difficult degree. The values of adsorption free energy（ △G） in the soil samples were ranged from-8. 81 to-10. 73 KJ/mol. And the adsorption belonged to spontaneous and physical process.【Conclusion】Metolachlor in the soil of sandy loam belonged to‘Can be leached＇catalog and‘difficult to be leached＇catalog in the soils of loam soil,loamy clay. The mobility of metolachlor in sandy loam is more than that of loamy clay and loam soil,which is more likely to cause pollution to groundwater.