Understanding the Equilibrium Ion Exchange Properties in Faujasite Zeolite from Monte Carlo Simulations

Jeffroy, Marie; Boutin, Anne; Fuchs, Alain H.

doi:10.1021/jp209067n

Cited by 37 publications

(45 citation statements)

References 35 publications

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“…In particular, it is essential to correctly capture the competition between ion-solvent and ion-framework interactions [21,22]. As a crude test of the force field used in the present study, we artificially increase the ion-water interaction by multiplying the corresponding Lennard-Jones interaction strength by a factor of 100.…”

Section: Discussionmentioning

confidence: 99%

Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Louisfrema

Rotenberg

Porcher

et al. 2015

Molecular Simulation

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Using neutron scattering and Monte Carlo simulation, we investigate the distribution of cations in Na 58 Y faujasite upon (de)hydration. We introduce a new method for the assignment of cations to specific sites in molecular simulations from their local environment. This allows us to bypass the need of the coordinates of crystallographic sites, which vary as water adsorption induces changes in the zeolite framework structure. While the agreement between experiments and simulation is excellent at high temperature, some differences are observed below 150°C. We show that these differences are due to the presence of water and that temperature itself as well as adsorption-induced deformation of the framework play a less important role. We demonstrate the migration of sodium to sites III upon water adsorption, not observed for other Si:Al ratios.

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Section: Discussionmentioning

confidence: 99%

Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Louisfrema

Rotenberg

Porcher

et al. 2015

Molecular Simulation

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“…Combining visualization with specific location analysis, as for example in the case of the location analysis of cations in a faujasite, provides a way of studying and understanding cation exchange phenomena [45] during waste water treatment.…”

Section: Post-processing: Convergence Visualization Analysismentioning

confidence: 99%

“…Molecular Dynamics and Monte-Carlo simulations have been used to study cation location in zeolites [49,50] and cation exchange [45]. The results show that the utilization of molecular simulation on such systems is very promising and can provide qualitatively and quantitatively accurate description.…”

Section: Limitationsmentioning

confidence: 99%

Molecular Simulation of Adsorption in Microporous Materials

Yiannourakou

Ungerer

LeBlanc

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Re´sume´-Mode´lisation mole´culaire de l'adsorption dans les solides microporeux -L'existence de logiciels industriels, la baisse du couˆt du calcul et la disponibilite´de champs de force e´prouve´s rendent la simulation mole´culaire de plus en plus attrayante pour les applications du domaine du ge´nie chimique. Nous pre´sentons ici plusieurs applications des techniques de simulation de Monte-Carlo, applique´es a`l'adsorption de fluides dans des solides microporeux (pores < 2 nm) comme les ze´olithes et des structures microporeuses a`base de carbone. L'adsorption a e´teḿ ode´lise´e par simulation dans l'ensemble Grand Canonique graˆce au logiciel MedeA Ò -GIBBS, en utilisant des grilles tridimensionnelles de valeurs pre´-calcule´es de l'e´nergie pour optimiser le temps calcul. MedeA Ò -GIBBS a aussi e´te´utilise´pour obtenir les potentiels chimiques ou les fugacite´s dans les phases fluides libres au moyen de l'ensemble Canonique (NVT) ou de l'ensemble isotherme-isobare (NPT). Les re´sultats de simulation ont e´te´compare´s avec des donne´es expe´rimentales d'isothermes d'adsorption de corps purs (gaz hydrocarbures, eau, aromatiques, e´thanethiol) dans plusieurs ze´olithes et a`plusieurs tempe´ratures. La coadsorption de me´langes (me´thane-e´thane, n-hexane-benze`ne) dans les ze´olithes a aussi e´te´e´tudie´e. Par exemple, l'inversion de se´lectivite´n-hexane/benze`ne entre la silicalite et les Na-faujasites est bien pre´dite avec des champs de force publie´s, et permettent de comprendre les me´canismes sousjacents. De meˆme, les isothermes d'adsorption des hydrocarbures le´gers et d'un mercaptan (e´thyl-thiol) sont bien de´crite. En ce qui concerne les adsorbants organiques (ke´roge`ne et charbons matures), des mode`les mole´culaires moyens ont e´te´construits en rendant compte des principaux traits connus de la structure chimique de ces mate´riaux. Par une simple relaxation ab ase de dynamique mole´culaire, nous avons pu obtenir des densite´s moyennes en bon accord avec les donne´es expe´rimentales disponibles, ce qui est tre`s encourageant. Nous avons aussi de´termine´les courbes isothermes d'exce`s d'adsorption en bon accord qualitatif avec celles re´cemment mesure´es sur des e´chantillons de charbon ou d'argiles en l'absence d'eau. Bien que pre´liminaires, ces re´sultats illustrent la puissance et la ge´ne´ralite´de la mode´lisation mole´culaire en vue de la compre´hension de syste`mes complexes dans des conditions ou`l'expe´rimentation est difficile.Abstract -Molecular Simulation of Adsorption in Microporous Materials -The development of industrial software, the decreasing cost of computing time, and the availability of well-tested Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 68 (2013), No. 6, pp. 977-994 Copyright Ó 2013, IFP Energies nouvelles DOI: 10.2516 forcefields make molecular simulation increasingly attractive for chemical engineers. We present here several applications of Monte-Carlo simulation techniques, applied to the adsorption of fluids in microporous solids such as...

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“…The procedure is reminiscent of Ref. [40]. In that reference, however, the ions swapped have the same charge and can be swapped one-for-one.…”

Section: Sorption Of Csmentioning

confidence: 99%

Thermodynamics, kinetics, and mechanics of cesium sorption in cement paste: A multiscale assessment

Arayro

Dufresne

Zhou

et al. 2018

Phys. Rev. Materials

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Cesium-137 is a common radioactive byproduct found in nuclear spent fuel. Given its 30 year half life, its interactions with potential storage materials-such as cement paste-is of crucial importance. In this paper, simulations are used to establish the interaction of calcium silicate hydrates (C-S-H)-the main binding phase of cement paste-with Cs at the nano-and mesoscale. Different C-S-H compositions are explored, including a range of Ca/Si ratios from 1.0 to 2.0. These calculations are based on a set of 150 atomistic models, which qualitatively and quantitatively reproduce a number of experimentally measured features of C-S-H-within limits intrinsic to the approximations imposed by classical molecular dynamics and the steps followed when building the models. A procedure where hydrated Ca 2+ ions are swapped for Cs 1+ ions shows that Cs adsorption in the C-S-H interlayer is preferred to Cs adsorption at the nanopore surface when Cs concentrations are lower than 0.19 Mol/kg. Interlayer sorption decreases as the Ca/Si ratio increases. The activation relaxation technique nouveau is used to access timescales out of the reach of traditional molecular dynamics (MD). It indicates that characteristic diffusion time for Cs 1+ in the C-S-H interlayer is on the order of a few hours. Cs uptake in the interlayer has little impact on the elastic response of C-S-H. It leads to swelling of the C-S-H grains, but mesoscale calculations that access length scales out of the range of MD indicate that this leads to practically negligible expansive pressures for Cs concentrations relevant to nuclear waste repositories.

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Understanding the Equilibrium Ion Exchange Properties in Faujasite Zeolite from Monte Carlo Simulations

Cited by 37 publications

References 35 publications

Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Molecular Simulation of Adsorption in Microporous Materials

Thermodynamics, kinetics, and mechanics of cesium sorption in cement paste: A multiscale assessment

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Understanding the Equilibrium Ion Exchange Properties in Faujasite Zeolite from Monte Carlo Simulations

Cited by 37 publications

References 35 publications

Cation redistribution upon dehydration of Na58Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Cation redistribution upon dehydration of Na58Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Molecular Simulation of Adsorption in Microporous Materials

Thermodynamics, kinetics, and mechanics of cesium sorption in cement paste: A multiscale assessment

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Product

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Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

Cation redistribution upon dehydration of Na₅₈Y faujasite zeolite: a joint neutron diffraction and molecular simulation study