Behavior of the Enthalpy of Adsorption in Nanoporous Materials Close to Saturation Conditions

Torres‐Knoop, Ariana; Poursaeidesfahani, Ali; Vlugt, Thijs J. H.; Dubbeldam, David

doi:10.1021/acs.jctc.6b01193

Cited by 49 publications

(41 citation statements)

References 53 publications

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“…The increase of Q st,exc with θ has also been observed for other gases, such as water [91], ethane [59], carbon dioxide [92,93] and methane [58]. Torres-Knopp et al [94] found that lateral interactions between hydrogen molecules and cooperative adsorption lead to an increase of Q st with θ. Figure 8 also shows that the higher the adsorption temperature, the higher the Q st,exc .…”

Section: Isosteric Heat Of Adsorptionmentioning

confidence: 71%

Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Sdanghi

Schaefer

Maranzana

et al. 2020

International Journal of Hydrogen Energy

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Hydrogen storage in activated carbons (ACs) has proven to be a realistic alternative to compression and liquefaction. Adsorption capacities up to 5.8 wt.% have indeed been obtained. The amount of adsorbed hydrogen depends on the textural properties of ACs, such as specific surface area and total pore volume. The modified Dubinin-Astakhov (MDA) equation proved to be a good analytical tool for describing hydrogen adsorption in a wide range of pressures and temperatures and for several adsorbents. The parameters of this model have been found to be somehow related to the textural properties of the adsorbent. Thus, we applied this model to understand better hydrogen adsorption on ACs over a wide range of pressures in relation to the textural properties of the ACs. We applied the MDA equation to evaluate also the isosteric heat of hydrogen adsorption, which was found to be in the range of 5 to 9 kJ mol-1. We compared the results obtained by applying the MDA equation with those obtained by both the sorption isosteric method and the Sips equation. This allowed finding the temperature dependence of the isosteric heat of adsorption, as well as its variation with respect to the textural properties of the ACs.

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Section: Isosteric Heat Of Adsorptionmentioning

confidence: 71%

Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Sdanghi

Schaefer

Maranzana

et al. 2020

International Journal of Hydrogen Energy

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“…5. The CFCMC methodology is described in further detail in the following references 52,[54][55][56] . In the CFCMC simulations, 100 attempts to change the fractional parameter of the fractional molecules were made per cycle, in addition to the normal moves named previously.…”

Section: Filling the Hydrate Structurementioning

confidence: 99%

Phase Diagram of Methane and Carbon Dioxide Hydrates Computed by Monte Carlo Simulations

Waage¹,

Vlugt

Kjelstrup³

2017

J. Phys. Chem. B

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Molecular Monte Carlo simulations are used to compute the three-phase (hydrate-liquid water-gas) equilibrium lines of methane and carbon dioxide hydrates, using the Transferable Potentials for Phase Equilibria model for carbon dioxide, the united atom optimized potential for liquid simulations model for methane, and the TIP4P/Ice and TIP4P/2005 models for water. The three-phase equilibrium temperatures have been computed for pressures between 50 and 4000 bar via free-energy calculations. The computed results are as expected for methane hydrates but deviate from the direct-coexistence molecular dynamics (MD) studies for carbon dioxide hydrates. At pressures higher than 1000 bar, both the methane and carbon dioxide hydrates dissociate at lower temperatures than expected from experiments and MD studies. The dissociation enthalpy is found to be largely independent on water models, and its values are measured to be 7.6 and 6.0 kJ/mol of water for methane hydrates and carbon dioxide hydrates, respectively. We evaluate the effect of systematic errors on the determination of chemical potentials and show that systematic errors of 0.1 kJ/mol in the chemical potential of water correspond to deviations of 5 K in the three-phase equilibrium temperatures.

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“…The CFCMC technique is frequently used for simulations that suffer from low acceptance probability of molecule insertions/removals. 1,45−55 Applications of this approach include computation of the loading and enthalpy of adsorption of guest molecules in porous materials near the saturation loading, 38,45 reaction equilibria of complex systems, 1 and solubilities of small molecules in ionic liquids. 43,44,46,47,56−59 For more details on the challenges of Monte Carlo simulations in open ensembles, the reader is referred to refs (60−62).…”

Section: Introductionmentioning

confidence: 99%

Efficient Application of Continuous Fractional Component Monte Carlo in the Reaction Ensemble

Poursaeidesfahani

Hens

Rahbari

et al. 2017

J. Chem. Theory Comput.

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122

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A new formulation of the Reaction Ensemble Monte Carlo technique (RxMC) combined with the Continuous Fractional Component Monte Carlo method is presented. This method is denoted by serial Rx/CFC. The key ingredient is that fractional molecules of either reactants or reaction products are present and that chemical reactions always involve fractional molecules. Serial Rx/CFC has the following advantages compared to other approaches: (1) One directly obtains chemical potentials of all reactants and reaction products. Obtained chemical potentials can be used directly as an independent check to ensure that chemical equilibrium is achieved. (2) Independent biasing is applied to the fractional molecules of reactants and reaction products. Therefore, the efficiency of the algorithm is significantly increased, compared to the other approaches. (3) Changes in the maximum scaling parameter of intermolecular interactions can be chosen differently for reactants and reaction products. (4) The number of fractional molecules is reduced. As a proof of principle, our method is tested for Lennard-Jones systems at various pressures and for various chemical reactions. Excellent agreement was found both for average densities and equilibrium mixture compositions computed using serial Rx/CFC, RxMC/CFCMC previously introduced by Rosch and Maginn (Journal of Chemical Theory and Computation, 2011, 7, 269–279), and the conventional RxMC approach. The serial Rx/CFC approach is also tested for the reaction of ammonia synthesis at various temperatures and pressures. Excellent agreement was found between results obtained from serial Rx/CFC, experimental results from literature, and thermodynamic modeling using the Peng–Robinson equation of state. The efficiency of reaction trial moves is improved by a factor of 2 to 3 (depending on the system) compared to the RxMC/CFCMC formulation by Rosch and Maginn.

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Behavior of the Enthalpy of Adsorption in Nanoporous Materials Close to Saturation Conditions

Cited by 49 publications

References 53 publications

Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Phase Diagram of Methane and Carbon Dioxide Hydrates Computed by Monte Carlo Simulations

Efficient Application of Continuous Fractional Component Monte Carlo in the Reaction Ensemble

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