Interfacial barriers to gas transport: probing solid-gas interfaces at the atomistic level

ABSTRACT

An understanding of interfacial barriers underpinning fluid transport in nanoporous membranes is critical for the design of efficient next generation membranes, to harness their potential for industrial scale separations. Such barriers include the contribution of external and internal interfacial barriers, and strongly depend on smoothness of the pore surface, pore size, shape, tortuosity, structural defects such as pore blockage and thermodynamic state of the fluid. We review recent progress in the transport of a fluid through nanoporous membrane materials such as zeolites and carbon nanotubes, which hold promise for industrial significance, but their application is subject to strong interfacial barriers. The contribution of interfacial barriers to the overall transport in these membrane materials is found to be particularly significant when the pore surface is uniform as well as at low temperatures and pressures. Further, such barriers that arise from internal defects such as grain boundaries are found to be remarkable and detrimental to separation kinetics. The internal interfacial barriers are found to be significant, and are enhanced when a dense medium such as a polymer is present at the interface, suggesting that interfacial barriers can play a key role in mixed matrix membranes and is an important area requiring further attention.

KEYWORDS:

• Interfacial resistance
• surface barriers
• ultra-thin membranes
• gas separation
• molecular dynamics simulation

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Ravi C. Dutta http://orcid.org/0000-0003-4068-2723

Suresh K. Bhatia http://orcid.org/0000-0001-9716-0112

Additional information

Funding

This work has been supported by the Australian Research Council [grant number DP150101824] through the Discovery scheme.