Adsorption of argon on pure silica MEL. Volumetric experiments and grand canonical Monte Carlo simulations

Sánchez-Gil, Vicente; Noya, Eva G.; Guil, J.M.; Lomba, Enrique; Valencia, Susana

doi:10.1016/j.micromeso.2015.10.023

Cited by 11 publications

(24 citation statements)

References 39 publications

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“…Such transitions were reported for adsorption of toluene 43 and argon. 44,45 Therefore, the force field used for molecular simulations could not fully reflect adsorption phenomena for this particular zeolite. It is worth noticing that the level of agreement between the calculated and experimental isotherms obtained by Marguta et al is very close to that found for adsorption isobars of C6−C8 in MEL in this work.…”

Section: Resultsmentioning

confidence: 99%

Adsorption of n-Alkanes in MFI and MEL: Quasi-Equilibrated Thermodesorption Combined with Molecular Simulations

et al. 2016

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Adsorption of n-alkanes on high silica MFI and MEL zeolites was studied by means of experimental quasi-equilibrated temperature-programmed desorption and adsorption (QE-TPDA) and Monte Carlo simulations. An unusual, isobaric approach to adsorption measurements and simulations was applied. Good agreement between the experimental and calculated data observed for MFI indicates that the QE-TPDA is a reliable method for studying porosity-related adsorptive properties of molecular sieves. The calculated average occupation profiles confirmed limited mobility of hexane and heptane molecules adsorbed in the sinusoidal channels on the MFI, thus proving the concept of order–disorder phase transition postulated in explanation of the two-step desorption profiles of these alkanes observed for MFI zeolites. Partial agreement of the calculated isobars with the experimental data found for zeolite MEL indicated that adsorption of n-alkanes in this structure is more complex than assumed in the simulation model. However, two-step desorption profiles and immobilization of the molecules adsorbed in the straight channels of the MEL structure were also found for hexane.

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Section: Resultsmentioning

confidence: 99%

Adsorption of n-Alkanes in MFI and MEL: Quasi-Equilibrated Thermodesorption Combined with Molecular Simulations

et al. 2016

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“…at 77 K. For that purpose from the final GCMC configurations for a given load, canonical Molecular Dynamics (MD) simulations were run for 5 × 10 6 steps and averages were calculated over 5000 configurations separated by 1000 steps. The loads were chosen such that in the case of MEL is close to the saturation and above the adsorption step present in the experimental isotherm, 37 and for MFI is just below the load corresponding to the adsorption step found at 77 K. 25 In the case of FAU, the loading corresponds to two thirds of saturation, and the adsorption isotherm does not present now any singular feature.…”

Section: Resultsmentioning

confidence: 99%

“…These correspond to the locations where the 6 Ar atoms will be found at full loading. 37 This figure is a clear illustration of the information on the spatial disposition of the adsorbates that this type of approach can furnish.…”

Section: -9mentioning

confidence: 99%

A three dimensional integral equation approach for fluids under confinement: Argon in zeolites

Lomba

Bores

Sánchez-Gil

et al. 2015

The Journal of Chemical Physics

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In this work, we explore the ability of an inhomogeneous integral equation approach to provide a full three dimensional description of simple fluids under conditions of confinement in porous media. Explicitly, we will consider the case of argon adsorbed into silicalite-1, silicalite-2, and an all-silica analogue of faujasite, with a porous structure composed of linear (and zig-zag in the case of silicalite-1) channels of 5-8 Å diameter. The equation is based on the three dimensional Ornstein-Zernike approximation proposed by Beglov and Roux [J. Chem. Phys. 103, 360 (1995)] in combination with the use of an approximate fluid-fluid direct correlation function furnished by the replica Ornstein-Zernike equation with a hypernetted chain closure. Comparison with the results of grand canonical Monte Carlo/molecular dynamics simulations evidences that the theory provides an accurate description for the three dimensional density distribution of the adsorbed fluid, both at the level of density profiles and bidimensional density maps across representative sections of the porous material. In the case of very tight confinement (silicalite-1 and silicalite-2), solutions at low temperatures could not be found due to convergence difficulties, but for faujasite, which presents substantially larger channels, temperatures as low as 77 K are accessible to the integral equation. The overall results indicate that the theoretical approximation can be an excellent tool to characterize the microscopic adsorption behavior of porous materials. C 2015 AIP Publishing LLC. [http://dx

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“…[24][25][26][27][28] In some cases, water at the solid interfaces can remain liquid-like even for temperatures much below the melting temperature of the bulk water. 26,29 The region in the pressure-temperature phase diagram in which these effects occur depends on the confining geometry, 26,27,30,31 on the dimensions, 32,33 and on the type of water-wall interaction. 16 In this paper, we study the structural and dynamical properties of the water confined in AlPO 4 -54 nanopores.…”

Section: Introductionmentioning

confidence: 99%

Structure and mobility of water confined in AlPO4-54 nanotubes

Gavazzoni

Giovambattista

Netz

et al. 2017

The Journal of Chemical Physics

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We performed molecular dynamics simulations of water confined within AlPO-54 nanotubes. AlPO-54 is an artificial material made of AlO and of PO in tetrahedra arranged in a periodic structure forming pores of approximately 1.3 nm in diameter. This makes AlPO-54 an excellent candidate for practical applications, such as for water filtration and desalination. In this work, the structural and dynamical properties of the confined water are analyzed for various temperatures and water loadings. We find that the water structure is controlled by the heterogeneity of the nanopore surface with the water molecules located preferentially next to the surface of oxygens of AlPO-54; consequently, at very low densities, water forms helicoidal structures in string-like arrangements.

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Adsorption of argon on pure silica MEL. Volumetric experiments and grand canonical Monte Carlo simulations

Cited by 11 publications

References 39 publications

Adsorption of n-Alkanes in MFI and MEL: Quasi-Equilibrated Thermodesorption Combined with Molecular Simulations

Adsorption of n-Alkanes in MFI and MEL: Quasi-Equilibrated Thermodesorption Combined with Molecular Simulations

A three dimensional integral equation approach for fluids under confinement: Argon in zeolites

Structure and mobility of water confined in AlPO4-54 nanotubes

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