Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO2 Separation Part 2: Permeation and Selectivity Study

Bünger, Lucas; Kurtz, Tim; Garbev, Krassimir; Stemmermann, Peter; Stapf, Dieter

doi:10.3390/membranes14070156

Open AccessArticle

Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study

by

Lucas Bünger

^*

,

Tim Kurtz

,

Krassimir Garbev

,

Peter Stemmermann

and

Dieter Stapf

Institute for Technical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany

^*

Author to whom correspondence should be addressed.

Membranes 2024, 14(7), 156; https://doi.org/10.3390/membranes14070156

Submission received: 31 May 2024 / Revised: 9 July 2024 / Accepted: 10 July 2024 / Published: 12 July 2024

(This article belongs to the Special Issue Advanced Membrane Materials for CO₂ Capture and Separation)

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Abstract

This study introduces an innovative approach to designing membranes capable of separating CO₂ from industrial gas streams at higher temperatures. The novel membrane design seeks to leverage a well-researched, high-temperature CO₂ adsorbent, hydrotalcite, by transforming it into a membrane. This was achieved by combining it with an amorphous organo-silica-based matrix, extending the polymer-based mixed-matrix membrane concept to inorganic compounds. Following the membrane material preparation and investigation of the individual membrane in Part 1 of this study, we examine its permeation and selectivity here. The pure 200 nm thick hydrotalcite membrane exhibits Knudsen behavior due to large intercrystalline pores. In contrast, the organo-silica membrane demonstrates an ideal selectivity of 13.5 and permeance for CO₂ of 1.3 × 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ at 25 °C, and at 150 °C, the selectivity is reduced to 4.3. Combining both components results in a hybrid microstructure, featuring selective surface diffusion in the microporous regions and unselective Knudsen diffusion in the mesoporous regions. Further attempts to bridge both components to form a purely microporous microstructure are outlined.

Keywords: inorganic membrane; silica membrane; hydrotalcite membrane; CO₂/N₂ separation; microporous mixed-matrix membrane

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MDPI and ACS Style

Bünger, L.; Kurtz, T.; Garbev, K.; Stemmermann, P.; Stapf, D. Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study. Membranes 2024, 14, 156. https://doi.org/10.3390/membranes14070156

AMA Style

Bünger L, Kurtz T, Garbev K, Stemmermann P, Stapf D. Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study. Membranes. 2024; 14(7):156. https://doi.org/10.3390/membranes14070156

Chicago/Turabian Style

Bünger, Lucas, Tim Kurtz, Krassimir Garbev, Peter Stemmermann, and Dieter Stapf. 2024. "Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study" Membranes 14, no. 7: 156. https://doi.org/10.3390/membranes14070156

APA Style

Bünger, L., Kurtz, T., Garbev, K., Stemmermann, P., & Stapf, D. (2024). Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study. Membranes, 14(7), 156. https://doi.org/10.3390/membranes14070156

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Mixed-Matrix Organo–Silica–Hydrotalcite Membrane for CO₂ Separation Part 2: Permeation and Selectivity Study

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