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Measuring Membrane Permeation Rates through the Optical Visualization of a Single Pore

Lookup NU author(s): Sotiria Tsochataridou, Dr Greg MutchORCiD, Dr Dragos Neagu, Dr Evangelos Papaioannou, Dr Brian Ray, Professor Ian Metcalfe



This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2020.

For re-use rights please refer to the publisher's terms and conditions.


Membranes are a critical technology for energy-efficient separation processes. The routine method of evaluating membrane performance is a permeation measurement. However, such measurements can be limited in terms of their utility: membrane microstructure is often poorly characterized; membranes or sealants leak; and conditions in the gas phase are poorly controlled and frequently far-removed from the conditions employed in the majority of real processes. Here, we demonstrate a new integrated approach to determine permeation rates, using two novel supported molten-salt membrane geometries. In both cases, the membranes comprise a solid support with laser-drilled pores, which are infiltrated with a highly CO2-selective molten carbonate salt. First, we fabricate an optically transparent single-crystal, single-pore model membrane by local laser drilling. By infiltrating the single pore with molten carbonate, monitoring the gas–liquid interface optically, and using image analysis on gas bubbles within the molten carbonate (because they change volume upon controlled changes in gas composition), we extract CO2 permeation rates with exceptional speed and precision. Additionally, in this arrangement, microstructural characterization is more straightforward and a sealant is not required, eliminating a major source of leakage. Furthermore, we demonstrate that the technique can be used to probe a previously unexplored driving force region, too low to access with conventional methods. Subsequently, we fabricate a leak-free tubular-supported molten-salt membrane with 1000 laser-drilled pores (infiltrated with molten carbonate) and employ a CO2-containing sweep gas to obtain permeation rates in a system that can be described with unprecedented precision. Together, the two approaches provide new ways to measure permeation rates with increased speed and at previously inaccesible conditions.

Publication metadata

Author(s): Tsochataridou S, Mutch GA, Neagu DN, Papaioannou EI, Sanjuan ML, Ray B, Merino RI, Orera VM, Metcalfe IS

Publication type: Article

Publication status: Published

Journal: ACS Applied Materials & Interfaces

Year: 2020

Volume: 12

Issue: 14

Pages: 16436-16441

Print publication date: 08/04/2020

Online publication date: 17/03/2020

Acceptance date: 17/03/2020

Date deposited: 25/03/2020

ISSN (print): 1944-8244

ISSN (electronic): 1944-8252

Publisher: American Chemical Society


DOI: 10.1021/acsami.0c01047


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