Winarto¹*, Paul Brumby², Kenji Yasuoka²

¹ Department of Mechanical Engineering, Faculty of Engineering, Brawijaya University, Malang, Indonesia 

² Department of Mechanical Engineering, Keio University, Japan

* winarto@ub.ac.id

Global warming, i.e. the increase of temperature on the earth, is the serious environmental issue caused by increasing concentrations of greenhouse gases in the atmosphere. Carbon dioxide (CO2) from flue- gas of combustion of fossil fuel in power plants and transportations is considered to be the main cause for the increase of greenhouse gases in the atmosphere and make significant contribution for the global warming [1,2]. Typically, the flue-gas contains three major components, i.e. about 80 % nitrogen (N2), 3 – 15 % CO2, and 3 – 15 % O2. Therefore, a technology to capture CO2 from the flue-gas is an important challenge in reducing the impact on the global warming [3,4]. Carbon nanotubes (CNTs) have many outstanding properties including rapid transport for fluids selectively. This property offers CNTs to be an excellent candidate material for separation processes such as water – alcohol separation [5-7] and oxygen-nitrogen separation [8]. In this study, we performed molecular dynamics simulation to investigate the separation effect of CO2 – N2 mixture and CO2 – N2 – O2 mixture as a representation of the flue-gas. The simulation system consists of a CNT embedded into graphene sheets at the both ends and two reservoirs at the both sides as shown in the Figure 1. The reservoirs were filled with a mixture of CO2 – N2 or CO2 – N2 – O2. The simulation results show that CO2 prefers to fill the CNT than the N2 or O2. The number of CO2 molecules in the CNT is much larger than that of N2 molecule or O2 molecule. A CNT preferentially adsorbs CO2 than N2 or O2 resulting the separation effect. The van der Waals interaction between CO2 and the CNT wall is the main factor inducing the separation of CO2 from the flue-gas.

References

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[5] Winarto, et. al. Nanoscale, 2015, 7, 12659

[6] Winarto, et. al. Phys. Chem. Chem. Phys., 2019, 21, 15431 

[7] Winarto, et. al. J. Chem. Phys., 2021, 155, 104701

[8] G. Arora and S. I. Sandler, Nano Lett., 2007, 7, 565–569.