Purpose: This study provides a comprehensive investigation of the link between gas transport and acoustic emission (AE) across porous membranes with varying pore sizes (20 nm, 8 nm and 0.55 nm). Methods: Using both microphone and piezoelectric transducer measurements, acoustic measurements were performed to reveal distinct behaviors depending on the sensor type and the membrane microstructure. Results: Microphone-recorded signals are dominated by gas resonances within the membrane’s tubular support—regardless of the membrane pore size. This was evidenced by the consistent harmonic patterns observed across all gases and membranes when normalized to the speed of sound of the respective gases. In contrast, piezoelectric transducer signals are measured in contact with the membrane and are therefore sensitive to fluid–structure interactions. These signals exhibit gas-specific acoustic signatures, particularly for membranes with larger pores. For the zeolite membrane (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$D=0.55$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>D</mi> <mo>=</mo> <mn>0.55</mn> </mrow> </math></EquationSource> </InlineEquation> nm), <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\hbox {CO}_2$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>CO</mtext> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> display a unique amplitude evolution, likely due to adsorption phenomena within the microporous structure displaying a very large surface area in contrast to the other materials under study. This is further supported by the contrasting signal-to-noise ratios observed between the gas phase and the solid membrane, thus highlighting the role of adsorption-induced energy transfer. Conclusion: The combination of AE techniques and harmonic analysis prove effective in distinguishing gas transport regimes and identifying the influence of microstructural features such as pore size and adsorption. These findings not only deepen our understanding of gas-membrane interactions, but also demonstrate the potential of AE as a non-invasive operando diagnostic tool for membrane characterization, with the extension to gas-mixture separations identified as a perspective for future work. Highlights: Gas transport and acoustic emission behavior across membranes are investigated. Microphone signals are dominated by gas resonances and unaffected by membrane pore size. Piezoelectric transducer signals reflect fluid–structure interactions and adsorption.

Operando Acoustic Emission Monitoring of Gas Transport in Porous Membranes

期刊论文
发表日期：

2026年4月10日

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Elise Doveri,
Christophe Charmette,
Martin Drobek,
Gilles Despaux,
Philippe Da Costa,
Benoit Coasne,
Emmanuel Le Clezio,
Anne Julbe

摘要

Purpose:

This study provides a comprehensive investigation of the link between gas transport and acoustic emission (AE) across porous membranes with varying pore sizes (20 nm, 8 nm and 0.55 nm).

Methods:

Using both microphone and piezoelectric transducer measurements, acoustic measurements were performed to reveal distinct behaviors depending on the sensor type and the membrane microstructure.

Results:

Microphone-recorded signals are dominated by gas resonances within the membrane’s tubular support—regardless of the membrane pore size. This was evidenced by the consistent harmonic patterns observed across all gases and membranes when normalized to the speed of sound of the respective gases. In contrast, piezoelectric transducer signals are measured in contact with the membrane and are therefore sensitive to fluid–structure interactions. These signals exhibit gas-specific acoustic signatures, particularly for membranes with larger pores. For the zeolite membrane ( $D=0.55$ $D = 0.55$ nm), $\hbox {CO}_2$ ${CO}_{2}$ display a unique amplitude evolution, likely due to adsorption phenomena within the microporous structure displaying a very large surface area in contrast to the other materials under study. This is further supported by the contrasting signal-to-noise ratios observed between the gas phase and the solid membrane, thus highlighting the role of adsorption-induced energy transfer.

Conclusion:

The combination of AE techniques and harmonic analysis prove effective in distinguishing gas transport regimes and identifying the influence of microstructural features such as pore size and adsorption. These findings not only deepen our understanding of gas-membrane interactions, but also demonstrate the potential of AE as a non-invasive operando diagnostic tool for membrane characterization, with the extension to gas-mixture separations identified as a perspective for future work.

Highlights:

Gas transport and acoustic emission behavior across membranes are investigated. Microphone signals are dominated by gas resonances and unaffected by membrane pore size. Piezoelectric transducer signals reflect fluid–structure interactions and adsorption.