Carbon Capture and Separation from CO2/N2/H2O Gaseous Mixtures in Bilayer Graphtriyne: A Molecular Dynamics Study

Molecular dynamics simulations have been performed for CO2 capture and separation from CO2/N2/H2O gaseous mixtures in bilayer graphtriyne. The gas uptake capacity, permeability as well as selectivity of the layers were simulated based on an improved formulation of force fields tested on accurate ab initio calculations on specific systems for mixture separation in post-combustion process. The effect of pressure and temperature on the separation performances of graphtriyne layers was investigated. Compared with the single layer graphtriyne, bilayer graphtriyne can adsorb more molecules with relatively good selectivity, due to the action of the interlayer region as an adsorption site. The interlayer adsorption selectivity of CO2/N2 and CO2/H2O at a temperature of 333 K and a pressure of 4 atm have been found to be equal to about 20.23 and 1.85, respectively. We also observed that the bilayer graphtriyne membrane has high CO2 and H2O permeances compared to N2, with permeance selectivity ranging from 4.8 to 6.5. Moreover, we found that permeation and adsorption depend on the applied temperature; at high temperatures, permeation and adsorption tend to decrease for all molecules.