Multi-scale modelling on PM2.5 encapsulation inside doubly-layered graphene

PM2.5 is classified as particles with radii <2.5 μm. It is evident that the continuous inhalation of such particles results in respiratory diseases such as lung cancer. Therefore, more effective adsorption of PM2.5 becomes crucial to comb the problem and the recent development of nanomaterials could provide a means to absorb and store PM2.5. In this reported work, a multi-scale modelling is used to investigate the storage of PM2.5, in particular carbon monoxide (CO), sulphur dioxide (SO₂) and nitrogen monoxide (NO) inside doubly-layered graphene sheets. While the molecular adsorption is modelled by a modified equation of states in the adsorption regime, the interactions between molecules are captured using a mean field theory. The maximum gravimetric uptake for CO, SO₂ and NO between the graphene of separation 20 Å is shown to be 19.45, 26.64 and 24.32 wt%, respectively, where the validity of the current model is confirmed by the case of hydrogen molecules with other experimental and simulations results. For higher temperatures, stronger pressure is needed to reach the same maximum uptakes as given at T = 77 K. The current model possesses the merit of rapid computational speed and is ready to be applied for other nanomaterials without conceptual difficulties. This graphene could be incorporated into an air purification system so as to raise the system's capacity in PM2.5 adsorption.