Adsorption of herbicide triclopyr on homoionic clays
摘要
The adsorption of the herbicide triclopyr on homoionic Fe￣(3+) , Al￣(3+) , Cu￣(2+) , K￣+ and Na￣+ ex-changed montmorillonite samples was investigated and the adsorption isotherm was described by the Fre-undlich equation. The adsorption capacity decreased in the order Fe￣(3+) , Al￣(3+) , Cu￣(2+) , Ca￣(2+) , K￣+ and Na￣+-clays. The triclopyr adsorption from chloroform solution was also studied by analytical, spectroscopic, and X- ray powder diffraction techniques. IR results suggested that the adsorption involved the formation of hydro-gen bonds with water molecules in the interlayer and might have involved both the protonation of the pyridinenitrogen atom, due to a proton transfer from the acid metal - bound water , and also the formation of directbounds between the carboxylate groups and the exchange cations. The pesticide forming complexes with inter-layer cations in montmorillite in soils might be extractable by solvents and was therefore releaed into the envi-ronment.