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F. Fromage - One of the best experts on this subject based on the ideXlab platform.
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Surface Complexation Modeling of Yb(III) and Cs(I) Sorption on Silica.
Journal of colloid and interface science, 1999Co-Authors: N. Marmier, Annie Delisée, F. FromageAbstract:Abstract A Surface Complexation model is used to describe sorption of ytterbium and cesium on the silica Surface. The constant capacitance model gives the description of the solid–solution interface chosen for this work. The first step in the modeling consists of extracting the Surface acidity constants. The result is: [equation]. The second step consists of the extraction of Surface Complexation constants for both ytterbium and cesium. The sorption of the cations is represented as follows: for the ytterbium sorption, [equation] for the cesium sorption, [equation]. In the case of cesium, the sorption of sodium is competitive and has to be considered: [equation]
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Surface Complexation modeling of yb iii ni ii and cs i sorption on magnetite
Joint International Conference on Information Sciences, 1999Co-Authors: N. Marmier, Annie Delisée, F. FromageAbstract:The sorption of ytterbium, nickel, and cesium on magnetite is studied via experiments. The affinity of the magnetite Surface is greater for ytterbium, then nickel, and nonexistent for cesium. Three different Surface Complexation models, with three different electrostatic descriptions of the interface, are used to fit the experiment data. These descriptions are given by the double layer model (DLM), the constant capacitance model (CCM), and a nonelectrostatic model (NEM). The results of fits give the same stoichiometries for the Surface reactions for the three tested models in similar Surface loading conditions. The values of the Surface constants obtained are the same, taking into account the error for DLM and CCM. NEM gives different values, even if the fit quality is comparable.
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Surface Complexation modeling of Yb(III) sorption and desorption on hematite and alumina
Journal of Contaminant Hydrology, 1997Co-Authors: N. Marmier, J. Dumonceau, F. FromageAbstract:Abstract Sorption and desorption of Yb(III) were studied on hematite and on alumina using a Surface Complexation model. The experimental methodology was conceived to allow an analysis of the data using a constant capacitance model. The FITEQL code was used for the calculations. The experimental results tend to show reversibility of sorption when the Surface loading is small, and irreversibility when the Surface loading is high. Surface Complexation modeling gives a good interpretation of these two phenomena, taking into account hydroxylation of the Surface complexes. In these two cases, it is possible to describe sorption and desorption curves with the same Surface stoichiometries and the same Surface Complexation constants. The existence of these Surface complexes depends on the pH of the solution, Surface loading, and reaction direction.
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Modeling of Radionuclides Sorption on Bentonite by Using Single Oxides Surface Complexation Models
MRS Proceedings, 1997Co-Authors: N. Marmier, F. Fromage, Annie Delisée, Eric GiffautAbstract:Bentonite could be one of the materials used in Engineered Barrier Systems. The aim of this work is to assess its sorbing properties using Surface Complexation modelling of Cs + , Ni 2+ and Yb 3+ sorption on single oxides
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Modeling of Yb(III) Sorption on Kaolinite by Using Single Oxide Surface Complexation Models
MRS Proceedings, 1994Co-Authors: N. Marmier, J. Dumonceau, Joël Chupeau, F. FromageAbstract:AbstractSurface Complexation model was used to describe ytterbium sorption on kaolinite using Surface acidity constants and Surface Complexation constants determined on alumina and silica.
Sabine Goldberg - One of the best experts on this subject based on the ideXlab platform.
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application of Surface Complexation models to anion adsorption by natural materials
Environmental Toxicology and Chemistry, 2014Co-Authors: Sabine GoldbergAbstract:Various chemical models of ion adsorption are presented and discussed. Chemical models, such as Surface Complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model, are described in the present study. Characteristics common to all the Surface Complexation models are equilibrium constant expressions, mass and charge balances, and Surface activity coefficient electrostatic potential terms. Methods for determining parameter values for Surface site density, capacitances, and Surface Complexation constants also are discussed. Spectroscopic experimental methods of establishing ion adsorption mechanisms include vibrational spectroscopy, nuclear magnetic resonance spectroscopy, electron spin resonance spectroscopy, X-ray absorption spectroscopy, and X-ray reflectivity. Experimental determinations of point of zero charge shifts and ionic strength dependence of adsorption results and molecular modeling calculations also can be used to deduce adsorption mechanisms. Applications of the Surface Complexation models to heterogeneous natural materials, such as soils, using the component additivity and the generalized composite approaches are described. Emphasis is on the generalized composite approach for predicting anion adsorption by soils. Continuing research is needed to develop consistent and realistic protocols for describing ion adsorption reactions on soil minerals and soils. The availability of standardized model parameter databases for use in chemical speciation–transport models is critical. Environ Toxicol Chem 2014;33:2172–2180. Published 2014 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and as such, is in the public domain in the United States.
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Application of Surface Complexation models to anion adsorption by natural materials.
Environmental toxicology and chemistry, 2014Co-Authors: Sabine GoldbergAbstract:Various chemical models of ion adsorption are presented and discussed. Chemical models, such as Surface Complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model, are described in the present study. Characteristics common to all the Surface Complexation models are equilibrium constant expressions, mass and charge balances, and Surface activity coefficient electrostatic potential terms. Methods for determining parameter values for Surface site density, capacitances, and Surface Complexation constants also are discussed. Spectroscopic experimental methods of establishing ion adsorption mechanisms include vibrational spectroscopy, nuclear magnetic resonance spectroscopy, electron spin resonance spectroscopy, X-ray absorption spectroscopy, and X-ray reflectivity. Experimental determinations of point of zero charge shifts and ionic strength dependence of adsorption results and molecular modeling calculations also can be used to deduce adsorption mechanisms. Applications of the Surface Complexation models to heterogeneous natural materials, such as soils, using the component additivity and the generalized composite approaches are described. Emphasis is on the generalized composite approach for predicting anion adsorption by soils. Continuing research is needed to develop consistent and realistic protocols for describing ion adsorption reactions on soil minerals and soils. The availability of standardized model parameter databases for use in chemical speciation-transport models is critical.
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Surface Complexation Modeling APPLICATION OF Surface Complexation MODELS TO ANION ADSORPTION BY NATURAL MATERIALS
2014Co-Authors: Sabine GoldbergAbstract:Various chemical models of ion adsorption are presented and discussed. Chemical models, such as Surface Complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model, are described in the present study. Characteristics common to all the Surface Complexation models are equilibrium constant expressions, mass and charge balances, and Surface activity coefficient electrostatic potential terms. Methods for determining parameter values for Surface site density, capacitances, and Surface Complexation constants also are discussed. Spectroscopic experimental methods of establishing ion adsorption mechanisms include vibrational spectroscopy, nuclear magnetic resonance spectroscopy, electron spin resonance spectroscopy, X-ray absorption spectroscopy, and X-ray reflectivity. Experimental determinations of pointof zero charge shiftsand ionic strength dependence ofadsorption results and molecular modelingcalculations also can be used to deduce adsorption mechanisms. Applications of the Surface Complexation models to heterogeneous natural materials, such as soils, using the component additivity and the generalized composite approaches are described. Emphasis is on the generalized composite approach for predicting anion adsorption by soils. Continuing research is needed to develop consistent and realistic protocols for describing ion adsorption reactions on soil minerals and soils. The availability of standardized model parameter databases for use in chemical speciation-transport models is critical. Environ Toxicol Chem 2014;33:2172-2180. Published 2014 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and as such, is in the public domain in the United States.
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mechanisms of arsenic adsorption on amorphous oxides evaluated using macroscopic measurements vibrational spectroscopy and Surface Complexation modeling
Journal of Colloid and Interface Science, 2001Co-Authors: Sabine Goldberg, Cliff T JohnstonAbstract:Arsenic adsorption on amorphous aluminum and iron oxides was investigated as a function of solution pH, solution ionic strength, and redox state. In this study in situ Raman and Fourier transform infrared (FTIR) spectroscopic methods were combined with sorption techniques, electrophoretic mobility measurements, and Surface Complexation modeling to study the interaction of As(III) and As(V) with amorphous oxide Surfaces. The speciation of As(III) and As(V) in aqueous solution was examined using Raman and attenuated total reflectance (ATR)-FTIR methods as a function of solution pH. The position of the As‐O stretching bands, for both As(III) and As(V), are strongly pH dependent. Assignment of the observed As‐O bands and their shift in position with pH was confirmed using semiempirical molecular orbital calculations. Similar pH-dependent frequency shifts are observed in the vibrational bands of As species sorbed on amorphous Al and Fe oxides. The mechanisms of As sorption to these Surfaces based on the spectroscopic, sorption, and electrophoretic mobility measurements are as follows: arsenate forms inner-sphere Surface complexes on both amorphous Al and Fe oxide while arsenite forms both inner- and outer-sphere Surface complexes on amorphous Fe oxide and outersphere Surface complexes on amorphous Al oxide. These Surface configurations were used to constrain the input parameters of the Surface Complexation models. Inclusion of microscopic and macroscopic experimental results is a powerful technique that maximizes chemical significance of the modeling approach. C ∞ 2001 Academic Press
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Use of Surface Complexation models in soil chemical systems
Advances in Agronomy, 1992Co-Authors: Sabine GoldbergAbstract:Publisher Summary This chapter presents five common Surface Complexation models of the mineral–solution interface and their use in describing soil chemical systems. Common model characteristics and adjustable parameters are discussed. For each model, Surface species, chemical reactions, equilibrium constant expressions, and Surface activity coefficients are described. Applications of the model to ion adsorption on soil minerals and soils are presented. Incorporation of Surface Complexation models into computer codes is also discussed. All Surface Complexation models are based on a balance of Surface charge expression. They contain at least one coulombic correction factor to account for the effect of Surface charge on Surface Complexation and explicitly define equilibrium constant expressions for Surface complexes. They contain mass balance equations for each type of Surface site and charge balance equations for each Surface plane of adsorption. Thus, all models contain adjustable parameters—the equilibrium constants, the capacitance density for the i th Surface plane, and the total number of reactive Surface hydroxyl groups.
N. Marmier - One of the best experts on this subject based on the ideXlab platform.
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Surface Complexation Modeling of Yb(III) and Cs(I) Sorption on Silica.
Journal of colloid and interface science, 1999Co-Authors: N. Marmier, Annie Delisée, F. FromageAbstract:Abstract A Surface Complexation model is used to describe sorption of ytterbium and cesium on the silica Surface. The constant capacitance model gives the description of the solid–solution interface chosen for this work. The first step in the modeling consists of extracting the Surface acidity constants. The result is: [equation]. The second step consists of the extraction of Surface Complexation constants for both ytterbium and cesium. The sorption of the cations is represented as follows: for the ytterbium sorption, [equation] for the cesium sorption, [equation]. In the case of cesium, the sorption of sodium is competitive and has to be considered: [equation]
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Surface Complexation modeling of yb iii ni ii and cs i sorption on magnetite
Joint International Conference on Information Sciences, 1999Co-Authors: N. Marmier, Annie Delisée, F. FromageAbstract:The sorption of ytterbium, nickel, and cesium on magnetite is studied via experiments. The affinity of the magnetite Surface is greater for ytterbium, then nickel, and nonexistent for cesium. Three different Surface Complexation models, with three different electrostatic descriptions of the interface, are used to fit the experiment data. These descriptions are given by the double layer model (DLM), the constant capacitance model (CCM), and a nonelectrostatic model (NEM). The results of fits give the same stoichiometries for the Surface reactions for the three tested models in similar Surface loading conditions. The values of the Surface constants obtained are the same, taking into account the error for DLM and CCM. NEM gives different values, even if the fit quality is comparable.
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Surface Complexation modeling of Yb(III) sorption and desorption on hematite and alumina
Journal of Contaminant Hydrology, 1997Co-Authors: N. Marmier, J. Dumonceau, F. FromageAbstract:Abstract Sorption and desorption of Yb(III) were studied on hematite and on alumina using a Surface Complexation model. The experimental methodology was conceived to allow an analysis of the data using a constant capacitance model. The FITEQL code was used for the calculations. The experimental results tend to show reversibility of sorption when the Surface loading is small, and irreversibility when the Surface loading is high. Surface Complexation modeling gives a good interpretation of these two phenomena, taking into account hydroxylation of the Surface complexes. In these two cases, it is possible to describe sorption and desorption curves with the same Surface stoichiometries and the same Surface Complexation constants. The existence of these Surface complexes depends on the pH of the solution, Surface loading, and reaction direction.
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Modeling of Radionuclides Sorption on Bentonite by Using Single Oxides Surface Complexation Models
MRS Proceedings, 1997Co-Authors: N. Marmier, F. Fromage, Annie Delisée, Eric GiffautAbstract:Bentonite could be one of the materials used in Engineered Barrier Systems. The aim of this work is to assess its sorbing properties using Surface Complexation modelling of Cs + , Ni 2+ and Yb 3+ sorption on single oxides
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Modeling of Yb(III) Sorption on Kaolinite by Using Single Oxide Surface Complexation Models
MRS Proceedings, 1994Co-Authors: N. Marmier, J. Dumonceau, Joël Chupeau, F. FromageAbstract:AbstractSurface Complexation model was used to describe ytterbium sorption on kaolinite using Surface acidity constants and Surface Complexation constants determined on alumina and silica.
Glenn A Waychunas - One of the best experts on this subject based on the ideXlab platform.
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uranium vi adsorption to ferrihydrite application of a Surface Complexation model
Geochimica et Cosmochimica Acta, 1994Co-Authors: T D Waite, James A Davis, Timothy E Payne, Glenn A WaychunasAbstract:Abstract A study of U(VI) adsorption by ferrihydrite was conducted over a wide range of U(VI) concentrations, pH, and at two partial pressures of carbon dioxide. A two-site (strong- and weak-affinity sites, FesOH and FewOH, respectively) Surface Complexation model was able to describe the experimental data well over a wide range of conditions, with only one species formed with each site type: an inner-sphere, mononuclear, bidentate complex of the type (FeO2)UO2. The existence of such a Surface species was supported by results of uranium EXAFS spectroscopy performed on two samples with U(VI) adsorption density in the upper range observed in this study (10 and 18% occupancy of total Surface sites). Adsorption data in the alkaline pH range suggested the existence of a second Surface species, modeled as a ternary Surface complex with UO2CO30 binding to a bidentate Surface site. Previous Surface Complexation models for U(VI) adsorption have proposed Surface species that are identical to the predominant aqueous species, e.g., multinuclear hydrolysis complexes or several U(VI)-carbonate complexes. The results demonstrate that the speciation of adsorbed U(VI) may be constrained by the coordination environment at the Surface, giving rise to Surface speciation for U(VI) that is significantly less complex than aqueous speciation.
Michael L Machesky - One of the best experts on this subject based on the ideXlab platform.
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A Unified Surface Complexation Modeling Approach for Chromate Adsorption on Iron Oxides
2019Co-Authors: Nefeli Maria Ompoti, Maria Chrysochoou, Michael L MacheskyAbstract:A multistart optimization algorithm for Surface Complexation equilibrium parameters (MUSE) was applied to a large and diverse data set for chromate adsorption on iron (oxy)hydroxides (ferrihydrite and goethite). Within the Basic Stern and the charge-distribution multisite Complexation (CD-MUSIC) framework, chromate binding constants and the Stern Layer capacitance were optimized simultaneously to develop a consistent parameter set for Surface Complexation models. This analysis resulted in three main conclusions regarding the model parameters: (a) There is no single set of parameter values that describes such diverse data sets when modeled independently. (b) Parameter differences among the data sets are mainly due to different amounts of total sites, i.e., Surface area and Surface coverages, rather than structural differences between the iron (oxy)hydroxides. (c) Unified equilibrium constants can be extracted if total site dependencies are taken into account. The implementation of the MUSE algorithm automated the process of optimizing the parameters in an objective and consistent manner and facilitated the extraction of predictive relationships for unified equilibrium constants. The extracted unified parameters can be implemented in reactive transport modeling in the field by either adopting the appropriate values for each Surface coverage or by estimating error bounds for different conditions. The evaluation of a forward model with unified parameters successfully predicted chromate adsorption for a range of capacitance values
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Surface Complexation of the zwitterionic fluoroquinolone antibiotic ofloxacin to nano anatase tio2 photocatalyst Surfaces
Environmental Science & Technology, 2012Co-Authors: Tias Paul, Michael L Machesky, Timothy J StrathmannAbstract:The Surface Complexation behavior of ofloxacin (OFX), a zwitterionic fluoroquinolone antibiotic, to nano-anatase titanium dioxide (TiO2) was characterized. OFX adsorption in aqueous TiO2 suspensions was measured as a function of pH, OFX concentration, and electrolyte type and concentration, and structural information was derived from in situ spectroscopic observations. An ultraviolet–visible spectral red shift upon OFX adsorption indicated formation of inner-sphere coordination complexes. Fourier transform infrared spectra of TiO2-adsorbed OFX were invariable over a wide concentration and pH range and were similar to measured spectra of dissolved species wherein the carboxylate group is deprotonated. A charge distribution Surface Complexation model constrained by spectroscopic observations was developed to describe macroscopic adsorption trends. A tridentate mode of adsorption involving bridging bidentate inner-sphere coordination of the deprotonated carboxylate group and hydrogen bonding through the adja...
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Surface Complexation of the zwitterionic fluoroquinolone antibiotic ofloxacin to nano-anatase TiO2 photocatalyst Surfaces
Environmental science & technology, 2012Co-Authors: Tias Paul, Michael L Machesky, Timothy J StrathmannAbstract:The Surface Complexation behavior of ofloxacin (OFX), a zwitterionic fluoroquinolone antibiotic, to nano-anatase titanium dioxide (TiO(2)) was characterized. OFX adsorption in aqueous TiO(2) suspensions was measured as a function of pH, OFX concentration, and electrolyte type and concentration, and structural information was derived from in situ spectroscopic observations. An ultraviolet-visible spectral red shift upon OFX adsorption indicated formation of inner-sphere coordination complexes. Fourier transform infrared spectra of TiO(2)-adsorbed OFX were invariable over a wide concentration and pH range and were similar to measured spectra of dissolved species wherein the carboxylate group is deprotonated. A charge distribution Surface Complexation model constrained by spectroscopic observations was developed to describe macroscopic adsorption trends. A tridentate mode of adsorption involving bridging bidentate inner-sphere coordination of the deprotonated carboxylate group and hydrogen bonding through the adjacent carbonyl group on the quinoline ring resulted in successful predictions of observed adsorption trends. In NaClO(4) electrolyte, spectroscopic data and model fitting suggested that OFX ion pairing with ClO(4)(-) enhanced adsorption under acidic conditions. Moreover, comparison of OFX adsorption data with the pH trend in the kinetics of OFX degradation by visible light (λ > 400 nm) photocatalysis suggested that adsorbed OFX-ClO(4)(-) ion pairs inhibit photodegradation.
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Modeling the Surface Complexation of calcium at the rutile-water interface to 250°C
Geochimica et Cosmochimica Acta, 2004Co-Authors: Moira K. Ridley, Michael L Machesky, David J. Wesolowski, Donald A. PalmerAbstract:Abstract The adsorption behavior of metal-(hydr)oxide Surfaces can be described and rationalized using a variety of Surface Complexation models. However, these models do not uniquely describe experimental data unless some additional insight into actual binding mechanisms for a given system is available. This paper presents the results of applying the MUlti SIte Complexation or MUSIC model, coupled with a Stern-based three layer description of the electric double layer, to Ca2+ adsorption data on rutile Surfaces from 25 to 250°C in 0.03 and 0.30 m NaCl background electrolyte. Model results reveal that the tetradentate adsorption configuration found for Sr2+ adsorbed on the rutile (110) Surface in the in situ X-ray standing wave experiments of Fenter et al. (2000) provides a good fit to all Ca2+ adsorption data. Furthermore, it is also shown that equally good fits result from other plausible adsorption complexes, including various monodentate and bidentate adsorption configurations. These results amply demonstrate the utility of in situ spectroscopic data to constrain Surface Complexation modeling, and the ability of the MUSIC model approach to accommodate this spectroscopic information. Moreover, this is the first use of any Surface Complexation model to describe multivalent ion adsorption systematically into the hydrothermal regime.
