Modelling proton and metal binding to humic substances with the NICA-EPN model

Environmental context The toxicity of metals in the environment is greatly influenced by natural organic matter owing to its ability to bind metals to form complexes that can be immobile and non-bioavailable. Sound mathematical models are important to reliably predict the behaviour of such contamina...

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Detalles Bibliográficos
Publicado: 2014
Materias:
adsorption
carboxylic acid
cation
chemical binding
complexation
environmental fate
Gibbs free energy
humic substance
isotherm
metal
numerical model
pollutant transport
polymer
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14482517_v11_n3_p318_Montenegro
http://hdl.handle.net/20.500.12110/paper_14482517_v11_n3_p318_Montenegro
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_14482517_v11_n3_p318_Montenegro
record_format dspace
spelling paper:paper_14482517_v11_n3_p318_Montenegro2023-06-08T16:16:10Z Modelling proton and metal binding to humic substances with the NICA-EPN model adsorption carboxylic acid cation chemical binding complexation environmental fate Gibbs free energy humic substance isotherm metal numerical model pollutant transport polymer Environmental context The toxicity of metals in the environment is greatly influenced by natural organic matter owing to its ability to bind metals to form complexes that can be immobile and non-bioavailable. Sound mathematical models are important to reliably predict the behaviour of such contaminants, and how they are affected by organic matter and other environmental colloids. Here a new model is discussed and compared with precedent ones. Abstract The mathematical modelling of metal cation-natural organic matter interactions is a fundamental tool in predicting the state and fate of pollutants in the environment. In this work, the binding of protons and metal cations to humic substances is modelled applying the Elastic Polyelectrolyte Network (EPN) electrostatic model with the Non-Ideal Competitive Adsorption (NICA) isotherm as the intrinsic part (NICA-EPN model). Literature data of proton and metal binding to humic substances at different pH and ionic strength values are analysed, discussing in depth the model predictions. The NICA-EPN model is found to describe well these phenomena. The electrostatic contribution to the Gibbs free energy of adsorbate-humic interaction in the EPN model is lower than that predicted by the Donnan phase model; the intrinsic mean binding constants for protons and metal cations are generally higher, closer to independent estimations and to the range of acid-base and complexation equilibrium values for common carboxylic acids. The results for metal cations are consistent with recent literature findings. The model predicts shrinking of the humic particles with increased metal binding, as a consequence of net charge decrease. © CSIRO 2014. 2014 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14482517_v11_n3_p318_Montenegro http://hdl.handle.net/20.500.12110/paper_14482517_v11_n3_p318_Montenegro
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
carboxylic acid
cation
chemical binding
complexation
environmental fate
Gibbs free energy
humic substance
isotherm
metal
numerical model
pollutant transport
polymer
spellingShingle adsorption
carboxylic acid
cation
chemical binding
complexation
environmental fate
Gibbs free energy
humic substance
isotherm
metal
numerical model
pollutant transport
polymer
Modelling proton and metal binding to humic substances with the NICA-EPN model
topic_facet adsorption
carboxylic acid
cation
chemical binding
complexation
environmental fate
Gibbs free energy
humic substance
isotherm
metal
numerical model
pollutant transport
polymer
description Environmental context The toxicity of metals in the environment is greatly influenced by natural organic matter owing to its ability to bind metals to form complexes that can be immobile and non-bioavailable. Sound mathematical models are important to reliably predict the behaviour of such contaminants, and how they are affected by organic matter and other environmental colloids. Here a new model is discussed and compared with precedent ones. Abstract The mathematical modelling of metal cation-natural organic matter interactions is a fundamental tool in predicting the state and fate of pollutants in the environment. In this work, the binding of protons and metal cations to humic substances is modelled applying the Elastic Polyelectrolyte Network (EPN) electrostatic model with the Non-Ideal Competitive Adsorption (NICA) isotherm as the intrinsic part (NICA-EPN model). Literature data of proton and metal binding to humic substances at different pH and ionic strength values are analysed, discussing in depth the model predictions. The NICA-EPN model is found to describe well these phenomena. The electrostatic contribution to the Gibbs free energy of adsorbate-humic interaction in the EPN model is lower than that predicted by the Donnan phase model; the intrinsic mean binding constants for protons and metal cations are generally higher, closer to independent estimations and to the range of acid-base and complexation equilibrium values for common carboxylic acids. The results for metal cations are consistent with recent literature findings. The model predicts shrinking of the humic particles with increased metal binding, as a consequence of net charge decrease. © CSIRO 2014.
title Modelling proton and metal binding to humic substances with the NICA-EPN model
title_short Modelling proton and metal binding to humic substances with the NICA-EPN model
title_full Modelling proton and metal binding to humic substances with the NICA-EPN model
title_fullStr Modelling proton and metal binding to humic substances with the NICA-EPN model
title_full_unstemmed Modelling proton and metal binding to humic substances with the NICA-EPN model
title_sort modelling proton and metal binding to humic substances with the nica-epn model
publishDate 2014
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14482517_v11_n3_p318_Montenegro
http://hdl.handle.net/20.500.12110/paper_14482517_v11_n3_p318_Montenegro
_version_ 1768543339979735040

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