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
The adsorption of the herbicide dimepiperate with homoionic Fe￣(3+) ,Al￣(3+),Cu￣(2+) ,Ca￣(2+) ,K￣+ and Na￣+ saturated montmorillonite in aqueous solution was investigated. The adsorption to six homoionic clays w...The adsorption of the herbicide dimepiperate with homoionic Fe￣(3+) ,Al￣(3+),Cu￣(2+) ,Ca￣(2+) ,K￣+ and Na￣+ saturated montmorillonite in aqueous solution was investigated. The adsorption to six homoionic clays was described well by the Freundlicb equation. The adsorption capacity decreases in order to Cu￣(2+) >Fe￣(3+) >Al￣(3+) >Ca￣(2+) >K￣+ >Na￣+ clay and the same order of their acidities except for Cu￣(2+),because Cu￣(2+) has great catalytical ability. The kinetic of its hydrolysis was also studied. Among the six metal ions,Cu￣(2+) clay exhibited a particular affect of catalysis. The IR results suggest that only findirig the adsorption of the hydrolytic product on Cu￣(2+)clay and dimepiperate on K￣+,Na￣+ clays, there being two compounds (dimepiperate and its hyrolytic product) adsorptions on Fe￣(3+) and Al￣(3+) clays.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.
文摘The adsorption of the herbicide dimepiperate with homoionic Fe￣(3+) ,Al￣(3+),Cu￣(2+) ,Ca￣(2+) ,K￣+ and Na￣+ saturated montmorillonite in aqueous solution was investigated. The adsorption to six homoionic clays was described well by the Freundlicb equation. The adsorption capacity decreases in order to Cu￣(2+) >Fe￣(3+) >Al￣(3+) >Ca￣(2+) >K￣+ >Na￣+ clay and the same order of their acidities except for Cu￣(2+),because Cu￣(2+) has great catalytical ability. The kinetic of its hydrolysis was also studied. Among the six metal ions,Cu￣(2+) clay exhibited a particular affect of catalysis. The IR results suggest that only findirig the adsorption of the hydrolytic product on Cu￣(2+)clay and dimepiperate on K￣+,Na￣+ clays, there being two compounds (dimepiperate and its hyrolytic product) adsorptions on Fe￣(3+) and Al￣(3+) clays.
