Molecular dynamic simulation study of selective separation of CO2 from N2 by graphtriyne membrane: A model for flue gas purification

In this work, the ability to selectively separate CO2 from N2 with a similar composition of flue gas by graphtriyne three-layer membrane was studied using molecular dynamics simulation. For this purpose, two sets of NVT and NPT ensembles were used. In the NPT ensemble, gas molecules were located on either side of the membrane and in the NVT ensemble, gas molecules were located on one side of the membrane. Then the effect of different temperatures and pressures in NPT ensemble and the effect of different temperatures and initial pressures in NVT ensemble on the membrane's ability to separate CO2 from N2 were investigated. The results showed that although the size of the graphtriyne pores were large enough for these molecules to pass through, in both ensembles, more CO2 molecules were adsorbed between the graphtriyne layers. It was also found that with increasing the temperature, the adsorption of N2 molecules decreased more than CO2 molecules, thus increasing the selectivity of CO2 uptake compared to N2 between graphtriyne layers. As the pressure increases, although the percentage of trapped CO2 molecules passing through the layers increases, the membrane still retains the selectivity of CO2 uptake relative to N2. Therefore, graphtriyne three-layer membrane can be introduced as very suitable and efficient for separation of CO2 from N2.