Adsorption and Gas Separation of Molecules by Carbon Nanohorns

Gatica, Silvina M.; Nekhai, Anton; Scrivener, Adam

doi:10.3390/molecules21050662

Cited by 10 publications

(9 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Carbon allotropes are often considered as candidates for adsorbents in physisorption for molecular capture or storage [7,8]. Apart from experimental studies, techniques used to model physisorption include molecular dynamics simulations [9][10][11][12], Monte Carlo methods [11,13,14] and continuum mathematical models [15][16][17][18] to name only a few. In particular, mathematical modeling of the interactions between various molecules and carbon surfaces has been extensive [19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Modeling Interactions between Graphene and Heterogeneous Molecules

et al. 2020

View full text Add to dashboard Cite

The Lennard–Jones potential and a continuum approach can be used to successfully model interactions between various regular shaped molecules and nanostructures. For single atomic species molecules, the interaction can be approximated by assuming a uniform distribution of atoms over surfaces or volumes, which gives rise to a constant atomic density either over or throughout the molecule. However, for heterogeneous molecules, which comprise more than one type of atoms, the situation is more complicated. Thus far, two extended modeling approaches have been considered for heterogeneous molecules, namely a multi-surface semi-continuous model and a fully continuous model with average smearing of atomic contribution. In this paper, we propose yet another modeling approach using a single continuous surface, but replacing the atomic density and attractive and repulsive constants in the Lennard–Jones potential with functions, which depend on the heterogeneity across the molecules, and the new model is applied to study the adsorption of coronene onto a graphene sheet. Comparison of results is made between the new model and two other existing approaches as well as molecular dynamics simulations performed using the LAMMPS molecular dynamics simulator. We find that the new approach is superior to the other continuum models and provides excellent agreement with molecular dynamics simulations.

show abstract

Section: Introductionmentioning

confidence: 99%

Modeling Interactions between Graphene and Heterogeneous Molecules

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Separating CO 2 from CH 4 is critical in industrial applications, transportation, and usage of methane [1]. Researchers have intensively investigated the adsorption of CO 2 /CH 4 mixtures on several materials like MOFs, mesoporous carbon, activated carbon, silicalite, C 186 schwarzite, and nanoporous carbon experimentally or theoretically [1,2,3,4,5,6,7,8,9].…”

Section: Introductionmentioning

confidence: 99%

“…of CO 2 /CH 4 mixtures on several materials like MOFs, mesoporous carbon, activated carbon, silicalite, C 186 schwarzite, and nanoporous carbon experimentally or theoretically [1,2,3,4,5,6,7,8,9].…”

mentioning

confidence: 99%

“…Gas separation by adsorption can be accomplished by three physical mechanisms: equilibria, kinetics, and steric effects. Equilibrium mechanisms rely on the strength of attraction between gas molecules and the substrate, while kinetic mechanisms involve the differences in the adsorption and transport rates of gas on and through the substrate [3]. Steric mechanisms, on the other hand, depend on the incompatibility between the size or shape of the adsorbate gas molecules and the pores of the substrate.…”

mentioning

confidence: 99%

“…Other groups evaluated the selectivity at low temperatures, finding extremely high values. For instance, Gatica et al [3], reported a numerical study of adsorption of CO 2 /CH 4 on carbon nanohorns, finding selectivities growing from 6 to 25 for a temperature drop from 193 K to 143 K. Maiga et al [7,6], estimated the selectivity of a CO 2 /CH 4 binary mixture in MOFs and graphene using GCMC and the ideal adsorbed solution theory (IAST). For MOFs, they predicted that the selectivity increased from 2 to 250 for temperatures dropping from 300 K to 120 K. For graphene at 40 K, the selectivity estimated by GCMC-IAST reaches the extremely high value of 6.24 × 10 6 .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Selective adsorption of carbon dioxide from mixed vapors by blockage of methane in graphene nanoribbons

Aljaddani

Gatica

2020

SN Appl. Sci.

View full text Add to dashboard Cite

We study numerically the adsorption of a mixture of CO 2 and CH 4 on a graphite substrate covered by graphene nanoribbons (NRs). The NRs are flat and parallel to the graphite surface, at a variable distance ranging from 6Å to 14Å. We show that the NRsgraphite substrate acts as an effective filter for CO 2 . Our study is based on Molecular Dynamics (MD) simulations. Methane is considered a spherical molecule, and carbon dioxide is represented as a linear rigid body. Graphite is modeled as a continuous material, while the NRs are approached atomistically. We observe that when the NRs are placed 6Å above the graphite surface, methane is blocked out, while CO 2 molecules can diffuse and be collected in between the NRs and the graphite surface. Consequently, the selectivity of CO 2 is extremely high. We also observe that the initial rate of adsorption of CO 2 is much higher than CH 4 . Overall we show that the filter can be optimized by controlling the gap between NRs and the NRs-graphite separation.

show abstract