12 Result(s)
within
Christophe Tournassat
-
Article
Open AccessResolving experimental biases in the interpretation of diffusion experiments with a user-friendly numerical reactive transport approach
The reactive transport code CrunchClay was used to derive effective diffusion coefficients (De), clay porosities (ε), and adsorption distribution coefficients (KD) from through-diffusion data while considering ac...
-
Article
Mössbauer spectrometry insights into the redox reactivity of Fe-bearing phases in the environment
Rates and mechanisms of important reactions in the cycling of electrons via the geochemical transformations of iron have been identified using Mössbauer spectrometry. The cycling of iron through various reserv...
-
Article
Reactive Transport Modeling with a Coupled OpenFOAM®-PHREEQC Platform
Reactive transport modeling has established itself as a key player to analyze sophisticated hydro-geochemical interactions that occur over spatiotemporal scales on par with subsurface applications. In this pap...
-
Article
Open AccessUncertainty propagation in pore water chemical composition calculation using surrogate models
Performance assessment in deep geological nuclear waste repository systems necessitates an extended knowledge of the pore water chemical conditions prevailing in host-rock formations. In the last two decades, ...
-
Article
Molecular-level understanding of metal ion retention in clay-rich materials
Clay minerals retain or adsorb metal ions in the Earth’s critical zone. Rocks, sediments and soils rich in clay minerals can concentrate rare earth elements (REEs) in ion adsorption-type deposits (IADs) and ar...
-
Article
Open AccessModeling diffusion processes in the presence of a diffuse layer at charged mineral surfaces: a benchmark exercise
The electrostatic properties of clay mineral surfaces play a significant role in their diffusion properties. The negative electrostatic potential field at clay mineral surfaces results in the presence of a dif...
-
Article
Open AccessA model for discrete fracture-clay rock interaction incorporating electrostatic effects on transport
A model based on the code CrunchClay is presented for a fracture-clay matrix system that takes electrostatic effects on transport into account. The electrostatic effects on transport include those associated w...
-
Article
Open AccessThermodynamic and crystallographic model for anion uptake by hydrated calcium aluminate (AFm): an example of molybdenum
Amongst all cement phases, hydrated calcium aluminate (AFm) plays a major role in the retention of anionic species. Molybdenum (Mo), whose 93Mo isotope is considered a major steel activation product, will be rele...
-
Article
Molecular Dynamics Simulations of Anion Exclusion in Clay Interlayer Nanopores
The aqueous chemistry of water films confined between clay mineral surfaces remains an important unknown in predictions of radioelement migration from radioactive waste repositories. This issue is particularly...
-
Article
Simulation of Cement/Clay Interactions: Feedback on the Increasing Complexity of Modelling Strategies
During the last decade, numerous studies have focused on long-term predictive reactive transport modelling of cement/clay interactions. These simulations have been performed using modelling strategies of growi...
-
Article
Experimental Evidence for Ca-Chloride Ion Pairs in the Interlayer of Montmorillonite. an XRD Profile Modeling Approach
Montmorillonite was equilibrated with high normality Cl− solutions to assess the possible presence of MeCl+ ion pairs in smectite interlayers suggested by chemical modeling of cation exchange experimental studies...
-
Article
Fe(II)-Na(I)-Ca(II) Cation Exchange on Montmorillonite in Chloride Medium: Evidence for Preferential Clay Adsorption of Chloride – Metal Ion Pairs in Seawater
Fe(II)–Ca(II), Fe(II)–Na(I), and Fe(II)–Ca(II)–Na(I) exchange experiments on montmorillonite were performed in chloride background. These experiments show the possible sorption of Fe2+ and FeCl+ ion pairs in exch...
