Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes

In this study we perform X-ray diffraction and XPS analysis to study the adsorption of the herbicide glyphosate on montmorillonite. Structures of the surface complexes are proposed based on the XPS and XRD patterns and explored using molecular modeling techniques. Adsorption isotherms showed multist...

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Autor principal:	Tribe, Lorena
Publicado:	2010
Materias:	Adsorption Clay mineral Glyphosate Herbicide Montmorillonite Adsorption energies Aluminol Amino moiety Basal spacing Bidentate complexes External surfaces Glyphosates Herbicide glyphosate High concentration Interlayer spaces Internal surfaces Macroscopic behaviors Mineral interactions Molecular modeling techniques Monodentates Multi-step Negative values PH dependence pH value Phosphonates Presence of water Silanol groups Surface complex Theoretical models Theoretical study Water molecule XPS XPS analysis XRD patterns Complexation Dyes Herbicides Minerals Molecules Silicate minerals Weed control X ray diffraction X ray diffraction analysis X ray photoelectron spectroscopy Clay minerals adsorption computer simulation concentration (composition) experimental mineralogy glyphosate isotherm microstructure montmorillonite numerical model pH theoretical study X-ray diffraction X-ray spectroscopy
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01691317_v50_n2_p167_Khoury http://hdl.handle.net/20.500.12110/paper_01691317_v50_n2_p167_Khoury
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_01691317_v50_n2_p167_Khoury
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spelling	paper:paper_01691317_v50_n2_p167_Khoury2023-06-08T15:18:11Z Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes Tribe, Lorena Adsorption Clay mineral Glyphosate Herbicide Montmorillonite Adsorption energies Aluminol Amino moiety Basal spacing Bidentate complexes External surfaces Glyphosates Herbicide glyphosate High concentration Interlayer spaces Internal surfaces Macroscopic behaviors Mineral interactions Molecular modeling techniques Monodentates Montmorillonite Multi-step Negative values PH dependence pH value Phosphonates Presence of water Silanol groups Surface complex Theoretical models Theoretical study Water molecule XPS XPS analysis XRD patterns Adsorption Complexation Dyes Herbicides Minerals Molecules Silicate minerals Weed control X ray diffraction X ray diffraction analysis X ray photoelectron spectroscopy Clay minerals adsorption computer simulation concentration (composition) experimental mineralogy glyphosate isotherm microstructure montmorillonite numerical model pH theoretical study X-ray diffraction X-ray spectroscopy In this study we perform X-ray diffraction and XPS analysis to study the adsorption of the herbicide glyphosate on montmorillonite. Structures of the surface complexes are proposed based on the XPS and XRD patterns and explored using molecular modeling techniques. Adsorption isotherms showed multistep profiles at all pHs studied, indicating the adsorption on aluminol and/or silanol groups of the external surface and in the interlayer space. PMG intercalation was indicated by the XRD patterns. The increase of the basal spacing as a function of the number of water molecules in the calculations indicated the appropriateness of the theoretical model to simulate macroscopic behaviors of the water/clay mineral interactions. Final conformations of the system determined by molecular mechanics indicated that the charged amino moiety was attracted by the negative surfaces of the interlayer space in absence or presence of water molecules, with marked pH dependence. Negative values of the estimated adsorption energies at all pH values studied suggested that glyphosate molecules were adsorbed via the amino moiety or through monodentate or bidentate complexes formed between the phosphonate moiety and the internal surfaces of the clay mineral, explaining the basal spacing changes at high concentrations of PMG. © 2010 Elsevier B.V. Fil:Tribe, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2010 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01691317_v50_n2_p167_Khoury http://hdl.handle.net/20.500.12110/paper_01691317_v50_n2_p167_Khoury
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Adsorption Clay mineral Glyphosate Herbicide Montmorillonite Adsorption energies Aluminol Amino moiety Basal spacing Bidentate complexes External surfaces Glyphosates Herbicide glyphosate High concentration Interlayer spaces Internal surfaces Macroscopic behaviors Mineral interactions Molecular modeling techniques Monodentates Montmorillonite Multi-step Negative values PH dependence pH value Phosphonates Presence of water Silanol groups Surface complex Theoretical models Theoretical study Water molecule XPS XPS analysis XRD patterns Adsorption Complexation Dyes Herbicides Minerals Molecules Silicate minerals Weed control X ray diffraction X ray diffraction analysis X ray photoelectron spectroscopy Clay minerals adsorption computer simulation concentration (composition) experimental mineralogy glyphosate isotherm microstructure montmorillonite numerical model pH theoretical study X-ray diffraction X-ray spectroscopy
spellingShingle	Adsorption Clay mineral Glyphosate Herbicide Montmorillonite Adsorption energies Aluminol Amino moiety Basal spacing Bidentate complexes External surfaces Glyphosates Herbicide glyphosate High concentration Interlayer spaces Internal surfaces Macroscopic behaviors Mineral interactions Molecular modeling techniques Monodentates Montmorillonite Multi-step Negative values PH dependence pH value Phosphonates Presence of water Silanol groups Surface complex Theoretical models Theoretical study Water molecule XPS XPS analysis XRD patterns Adsorption Complexation Dyes Herbicides Minerals Molecules Silicate minerals Weed control X ray diffraction X ray diffraction analysis X ray photoelectron spectroscopy Clay minerals adsorption computer simulation concentration (composition) experimental mineralogy glyphosate isotherm microstructure montmorillonite numerical model pH theoretical study X-ray diffraction X-ray spectroscopy Tribe, Lorena Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
topic_facet	Adsorption Clay mineral Glyphosate Herbicide Montmorillonite Adsorption energies Aluminol Amino moiety Basal spacing Bidentate complexes External surfaces Glyphosates Herbicide glyphosate High concentration Interlayer spaces Internal surfaces Macroscopic behaviors Mineral interactions Molecular modeling techniques Monodentates Montmorillonite Multi-step Negative values PH dependence pH value Phosphonates Presence of water Silanol groups Surface complex Theoretical models Theoretical study Water molecule XPS XPS analysis XRD patterns Adsorption Complexation Dyes Herbicides Minerals Molecules Silicate minerals Weed control X ray diffraction X ray diffraction analysis X ray photoelectron spectroscopy Clay minerals adsorption computer simulation concentration (composition) experimental mineralogy glyphosate isotherm microstructure montmorillonite numerical model pH theoretical study X-ray diffraction X-ray spectroscopy
description	In this study we perform X-ray diffraction and XPS analysis to study the adsorption of the herbicide glyphosate on montmorillonite. Structures of the surface complexes are proposed based on the XPS and XRD patterns and explored using molecular modeling techniques. Adsorption isotherms showed multistep profiles at all pHs studied, indicating the adsorption on aluminol and/or silanol groups of the external surface and in the interlayer space. PMG intercalation was indicated by the XRD patterns. The increase of the basal spacing as a function of the number of water molecules in the calculations indicated the appropriateness of the theoretical model to simulate macroscopic behaviors of the water/clay mineral interactions. Final conformations of the system determined by molecular mechanics indicated that the charged amino moiety was attracted by the negative surfaces of the interlayer space in absence or presence of water molecules, with marked pH dependence. Negative values of the estimated adsorption energies at all pH values studied suggested that glyphosate molecules were adsorbed via the amino moiety or through monodentate or bidentate complexes formed between the phosphonate moiety and the internal surfaces of the clay mineral, explaining the basal spacing changes at high concentrations of PMG. © 2010 Elsevier B.V.
author	Tribe, Lorena
author_facet	Tribe, Lorena
author_sort	Tribe, Lorena
title	Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
title_short	Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
title_full	Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
title_fullStr	Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
title_full_unstemmed	Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes
title_sort	glyphosate adsorption on montmorillonite: an experimental and theoretical study of surface complexes
publishDate	2010
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01691317_v50_n2_p167_Khoury http://hdl.handle.net/20.500.12110/paper_01691317_v50_n2_p167_Khoury
work_keys_str_mv	AT tribelorena glyphosateadsorptiononmontmorilloniteanexperimentalandtheoreticalstudyofsurfacecomplexes
_version_	1768546625610842112

Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes

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