As(III)-HA binding parameters

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Table of contents

Chapitre I : Complexation de l’arsenite par les groupements thiols de la matière organique
1 Introduction
2 Experimental, analytical and modeling methods
2.1 Reagents and materials
2.2 Experimental setup
2.3 Chemical analyses
2.4 Determination of the PHREEQC-Model VI binding parameters
2.4.1 Thiol implementation in PHREEQC-Model VI and the models used
2.4.2 Electrostatic model
2.4.3 Fitting the binding parameters
2.4.4 Dataset from the literature
3 Results
3.1 S(-II) grafting and titration
3.2 Adsorption isotherms
3.3 H-HA model
3.4 As-HA model
3.5 Simulations with the Mono and Tri models
4 Discussion
4.1 H-HA parameters
4.2 As(III)-HA binding parameters
4.3 Implications of the direct binding mechanism evidenced
Conclusion and perspectives
Chapitre II : Complexation du Fe(II) par les substances humiques : apport de la modélisation
1 Introduction
2 Experimental, analytical and modeling methods
2.1 Reagents and materials
2.2 Setup of the binding experiments
2.3 Chemical analyses
2.4 Determination of the PHREEQC-Model VI binding parameters
2.4.1 PHREEQC-Model VI
2.4.2 PHREEPLOT
2.5 LFER linear free energy relationship
3 Results
3.1 Experimental results
3.1.1 Adsorption isotherm
3.1.2 pH sorption edge
3.2 Model results
3.2.1 Adsorption isotherm
3.2.2 pH adsorption edge
3.3 Fe(II) speciation onto HA binding sites
3.3.1 Adsorption isotherm
3.3.2 pH adsorption edge
4 Discussion
4.1 Validation of the set of binding parameters
4.2 Fe(II) speciation onto HA binding sites
4.3 Environmental implications
Conclusions
Chapitre III : L’As(III) est-il capable de former des complexes ternaires avec la matière organique via Fe(II) et Fe(III) ionique?
1 Introduction
2 Experimental section
2.1 Experimental setup
2.2 Chemical analyses
2.3 Modeling
2.3.1 Model description
2.3.2 Binding parameters and modeling strategy
3 Results
3.1 As(III)-Fe(II)-AH experimental and modelling data
3.2 As(III)-Fe(III)-AH experimental and modeling data
4 Discussion
4.1 Monodentate or bidentate Fe(II)-HA sites: which ones complex As(III) most efficiently?
4.2 Instructions to better model As(III)-Fe(II)-HA interactions
4.3 Interpretation of As(III)-Fe(III)-AH data
4.4 Environmental implications
Conclusions et perspectives
1 Conclusions
1.1 La complexation directe d’As(III) par la MO est-elle possible?
1.2 La MO est-elle réellement un fort complexant du Fe(II)?
1.3 Est-il possible de former des complexes ternaires As(III)-Fe(II, III) ionique-MO?
1.4 Dynamique de l’As en solution dans les zones humides
2 Perspectives
2.1 Perspectives analytiques
2.2 Modèle de complexation à la surface des AH
2.3 Compétition ou formation d’autres complexes ternaires?
ANNEXES