A molecular dynamics study of enhanced CO separation boron nitride nanotubes embedded in a silicon nitride membrane.

In this work, we performed molecular dynamics (MD) simulations to investigate CO capture from flue gases with boron nitride nanotubes (BNNTs) and BNNTs embedded inside a silicon nitride (SiN) membrane. The CO molecules preferentially fill and occupy the BNNTs over N molecules. The high selectivity of BNNTs to capture CO rather than N results in a large separation effect. It was found that the CO molecules within the BNNTs form an ordered solid structure. Further to this, we investigated how the separation performance may be enhanced by placing BNNTs inside a silicon nitride (SiN) membrane. The presence of the SiN membrane was found to alter the solid CO structures. This change is attributed to the resulting non-uniform electric field inside the BNNTs. The altered electrostatic and van der Waals interaction experienced by CO due to the presence of the SiN membrane leads to an enhancement of the previously mentioned separation effect. This work demonstrates the great potential for BNNTs, in particular those embedded in SiN membranes, for use in carbon capture applications.