2023/07/19 by Carlos Alberto Martins Junior, Junior, Carlos Alberto Martins, Henrique Musseli Cezar +5
Chemistry · Engineering · Physics and Astronomy · #Advanced Mathematical Theories and Applications #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Phase Equilibria and Thermodynamics
paper · pdf · doi:10.48550/arxiv.2307.10117
openalex publication_date 2023/07/19 · openalex created_date 2023/07/21 · openalex updated_date 2026/08/01
The separation of carbon dioxide CO2 from nitrogen gas (N2), the main component of flue gas, has become an emerging action to mitigate climate change. Feasible and efficient approaches to exploring the separation properties of materials are molecular dynamics (MD) and Monte Carlo (MC) simulations. In these approaches, a careful choice of force fields is required to avoid unrealistic predictions of thermodynamic properties. However, most studies use Lorentz-Berthelot combining rules (LB) to obtain the interaction between different species, an approximation that could not capture the essence of interfacial interactions. In this context, we verified how accurate LB is in describing the interaction of N2 molecules and carbon nanostructures by comparing the interaction energies from LB with those from density functional theory (DFT) calculations. We selected carbon nanomaterials because they are considered promising materials to perform N2/CO2 separation. The results show that the LB underestimates the interaction energies and affects the prediction of fundamental properties of solid-fluid interfacial interactions. To overcome this limitation, we parametrized a Lennard-Jones potential using energies and forces from DFT, obtained through the van der Waals functional KBM. The proposed potential show good transferability and agreement to ab-initio calculations. Grand Canonical Monte Carlo simulations were performed to verify the effects of employing LB in predicting the amount of nitrogen gas adsorbed inside different CNTs. LB predicts a lower density inside them. Moreover, our results suggest that LB leads to a different characterization of the adsorption properties of carbon nanotubes, by changing significantly the adsorption isotherm.