Pb(II) binding to humic substances: An equilibrium and spectroscopic study

The binding of Pb(II) to humic acids is studied through an approach combining equilibrium and spectroscopic measurements. The methods employed are potentiometric and fluorometric titrations, fluorescence excitation-emission matrices (EEM) and IR spectroscopy. Potentiometric titration curves are anal...

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Autores principales:	Orsetti, S., Marco-Brown, J.L., Andrade, E.M., Molina, F.V.
Formato:	JOUR
Materias:	Affinity distributions Fluorescence excitation-emission matrices Monomodal distribution Multidentate complexation Parallel factor analysis Polyelectrolyte networks Potentiometric titrations Spectroscopic measurements Carboxylation Fluorescence Metal ions Molecules Potentiometers (electric measuring instruments) Spectroscopic analysis Titration Voltammetry Lead carboxylic acid humic acid lead metal ion polyelectrolyte chemical binding complexation concentration (composition) equilibrium humic substance spectroscopy article binding affinity complex formation excitation emission matrice fluorescence spectroscopy factorial analysis fluorescence spectroscopy fluorometry infrared spectroscopy metal binding potentiometric titration Raman spectrometry Fluorometry Humic Substances Models, Chemical Potentiometry Spectrophotometry, Infrared Static Electricity
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_0013936X_v47_n15_p8325_Orsetti
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_0013936X_v47_n15_p8325_Orsetti
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spelling	todo:paper_0013936X_v47_n15_p8325_Orsetti2023-10-03T14:11:42Z Pb(II) binding to humic substances: An equilibrium and spectroscopic study Orsetti, S. Marco-Brown, J.L. Andrade, E.M. Molina, F.V. Affinity distributions Fluorescence excitation-emission matrices Monomodal distribution Multidentate complexation Parallel factor analysis Polyelectrolyte networks Potentiometric titrations Spectroscopic measurements Carboxylation Fluorescence Metal ions Molecules Potentiometers (electric measuring instruments) Spectroscopic analysis Titration Voltammetry Lead carboxylic acid humic acid lead metal ion polyelectrolyte chemical binding complexation concentration (composition) equilibrium humic substance lead spectroscopy article binding affinity complex formation excitation emission matrice fluorescence spectroscopy factorial analysis fluorescence spectroscopy fluorometry humic substance infrared spectroscopy metal binding potentiometric titration Raman spectrometry spectroscopy Fluorometry Humic Substances Lead Models, Chemical Potentiometry Spectrophotometry, Infrared Static Electricity The binding of Pb(II) to humic acids is studied through an approach combining equilibrium and spectroscopic measurements. The methods employed are potentiometric and fluorometric titrations, fluorescence excitation-emission matrices (EEM) and IR spectroscopy. Potentiometric titration curves are analyzed using the NICA equations and an electrostatic model treating the humic particles as an elastic polyelectrolyte network. EEMs are analyzed using parallel factor analysis, decomposing the signal in its independent components and finding their dependence on Pb(II) activity. Potentiometric results are consistent with bimodal affinity distributions for Pb(II) binding, whereas fluorometric titrations are explained by monomodal distributions. EEM analysis is consistent with three independent components in the humic fluorescence response, which are assigned to moieties with different degree of aromaticity. All three components show a similar quenching behavior upon Pb(II) binding, saturating at relatively low Pb(II) concentrations. This is attributed to metal ion induced aggregation of humic molecules, resulting in the interaction between the aromatic groups responsible for fluorescence; this is also consistent with IR spectroscopy results. The observed behavior is interpreted considering that initial metal binding (observed as strongly binding sites), correspond to bi- or multidentate complexation to carboxylate groups, including binding between groups of different humic molecules, promoting aggregation; further metal ions (observed as weakly binding sites) bind to single ligand groups. © 2013 American Chemical Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0013936X_v47_n15_p8325_Orsetti
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Affinity distributions Fluorescence excitation-emission matrices Monomodal distribution Multidentate complexation Parallel factor analysis Polyelectrolyte networks Potentiometric titrations Spectroscopic measurements Carboxylation Fluorescence Metal ions Molecules Potentiometers (electric measuring instruments) Spectroscopic analysis Titration Voltammetry Lead carboxylic acid humic acid lead metal ion polyelectrolyte chemical binding complexation concentration (composition) equilibrium humic substance lead spectroscopy article binding affinity complex formation excitation emission matrice fluorescence spectroscopy factorial analysis fluorescence spectroscopy fluorometry humic substance infrared spectroscopy metal binding potentiometric titration Raman spectrometry spectroscopy Fluorometry Humic Substances Lead Models, Chemical Potentiometry Spectrophotometry, Infrared Static Electricity
spellingShingle	Affinity distributions Fluorescence excitation-emission matrices Monomodal distribution Multidentate complexation Parallel factor analysis Polyelectrolyte networks Potentiometric titrations Spectroscopic measurements Carboxylation Fluorescence Metal ions Molecules Potentiometers (electric measuring instruments) Spectroscopic analysis Titration Voltammetry Lead carboxylic acid humic acid lead metal ion polyelectrolyte chemical binding complexation concentration (composition) equilibrium humic substance lead spectroscopy article binding affinity complex formation excitation emission matrice fluorescence spectroscopy factorial analysis fluorescence spectroscopy fluorometry humic substance infrared spectroscopy metal binding potentiometric titration Raman spectrometry spectroscopy Fluorometry Humic Substances Lead Models, Chemical Potentiometry Spectrophotometry, Infrared Static Electricity Orsetti, S. Marco-Brown, J.L. Andrade, E.M. Molina, F.V. Pb(II) binding to humic substances: An equilibrium and spectroscopic study
topic_facet	Affinity distributions Fluorescence excitation-emission matrices Monomodal distribution Multidentate complexation Parallel factor analysis Polyelectrolyte networks Potentiometric titrations Spectroscopic measurements Carboxylation Fluorescence Metal ions Molecules Potentiometers (electric measuring instruments) Spectroscopic analysis Titration Voltammetry Lead carboxylic acid humic acid lead metal ion polyelectrolyte chemical binding complexation concentration (composition) equilibrium humic substance lead spectroscopy article binding affinity complex formation excitation emission matrice fluorescence spectroscopy factorial analysis fluorescence spectroscopy fluorometry humic substance infrared spectroscopy metal binding potentiometric titration Raman spectrometry spectroscopy Fluorometry Humic Substances Lead Models, Chemical Potentiometry Spectrophotometry, Infrared Static Electricity
description	The binding of Pb(II) to humic acids is studied through an approach combining equilibrium and spectroscopic measurements. The methods employed are potentiometric and fluorometric titrations, fluorescence excitation-emission matrices (EEM) and IR spectroscopy. Potentiometric titration curves are analyzed using the NICA equations and an electrostatic model treating the humic particles as an elastic polyelectrolyte network. EEMs are analyzed using parallel factor analysis, decomposing the signal in its independent components and finding their dependence on Pb(II) activity. Potentiometric results are consistent with bimodal affinity distributions for Pb(II) binding, whereas fluorometric titrations are explained by monomodal distributions. EEM analysis is consistent with three independent components in the humic fluorescence response, which are assigned to moieties with different degree of aromaticity. All three components show a similar quenching behavior upon Pb(II) binding, saturating at relatively low Pb(II) concentrations. This is attributed to metal ion induced aggregation of humic molecules, resulting in the interaction between the aromatic groups responsible for fluorescence; this is also consistent with IR spectroscopy results. The observed behavior is interpreted considering that initial metal binding (observed as strongly binding sites), correspond to bi- or multidentate complexation to carboxylate groups, including binding between groups of different humic molecules, promoting aggregation; further metal ions (observed as weakly binding sites) bind to single ligand groups. © 2013 American Chemical Society.
format	JOUR
author	Orsetti, S. Marco-Brown, J.L. Andrade, E.M. Molina, F.V.
author_facet	Orsetti, S. Marco-Brown, J.L. Andrade, E.M. Molina, F.V.
author_sort	Orsetti, S.
title	Pb(II) binding to humic substances: An equilibrium and spectroscopic study
title_short	Pb(II) binding to humic substances: An equilibrium and spectroscopic study
title_full	Pb(II) binding to humic substances: An equilibrium and spectroscopic study
title_fullStr	Pb(II) binding to humic substances: An equilibrium and spectroscopic study
title_full_unstemmed	Pb(II) binding to humic substances: An equilibrium and spectroscopic study
title_sort	pb(ii) binding to humic substances: an equilibrium and spectroscopic study
url	http://hdl.handle.net/20.500.12110/paper_0013936X_v47_n15_p8325_Orsetti
work_keys_str_mv	AT orsettis pbiibindingtohumicsubstancesanequilibriumandspectroscopicstudy AT marcobrownjl pbiibindingtohumicsubstancesanequilibriumandspectroscopicstudy AT andradeem pbiibindingtohumicsubstancesanequilibriumandspectroscopicstudy AT molinafv pbiibindingtohumicsubstancesanequilibriumandspectroscopicstudy
_version_	1807317043858374656

Pb(II) binding to humic substances: An equilibrium and spectroscopic study

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