Joint SFB 1313 and CRC 1333 Publication "Adsorption of light gases in covalent organic frameworks: comparison of classical density functional theory and grand canonical Monte Carlo simulations"

New joint SFB 1313 and CRC 1333 publication (University of Stuttgart), published in Microporous and Mesoporous Materials. The paper has been prepared within SFB 1313's research project A01:and CRC 1333's research project C5.

"Adsorption of light gases in covalent organic frameworks: comparison of classical density functional theory and grand canonical Monte Carlo simulations"

Authors

• Christopher Keßler (University Stuttgart, CRC 1333 research project C5)
• Johannes Eller (University Stuttgart, SFB 1313 research project A01)
• Joachim Groß (University Stuttgart, SFB 1313 research project A01 and CRC 1333 research project C5)
• Niels Hansen (University Stuttgart, CRC 1333 research project C5)

Abstract

A classical density functional theory (cDFT) based on the PC-SAFT equation of state is proposed for the calculation of adsorption equilibria of pure substances and their mixtures in covalent organic frameworks (COFs). Adsorption isotherms of methane, ethane, n-butane and nitrogen in the COFs TpPa-1 and 2,3-DhaTph are calculated and compared to results from grand canonical Monte Carlo (GCMC) simulations. Mixture adsorption is investigated for the methane/ethane and methane/n-butane binary systems. Excellent agreement between PC-SAFT DFT and GCMC is obtained for all adsorption isotherms up to pressures of 50 bar. The cDFT formalism accurately predicts the selective accumulation of longer hydrocarbons for binary mixtures in the considered COFs. This application shows substantial predictive power of PC-SAFT DFT solved in three-dimensional geometries and the results suggest the method can in the future also be applied for efficient optimization of force field parameters or of structural properties of the porous material based on an analytical theory as opposed to a stochastic simulation.