Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation w...Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation well (r 2 ≥0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pratilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these asetanilide herbicides. Multivariant correlation regression between Kf (1/n) and two factors, water solubility (S.) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/S. and OM/S. well, showing that high S. corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.展开更多
基金the National Natural Science Foundation of China (Nos: 29477274 and 3967O420)
文摘Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation well (r 2 ≥0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pratilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these asetanilide herbicides. Multivariant correlation regression between Kf (1/n) and two factors, water solubility (S.) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/S. and OM/S. well, showing that high S. corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.
