In a significant stride towards enhancing gas separation technologies, researchers have developed a novel carbon molecular sieve (CMS) membrane that could revolutionize the energy sector. The study, led by Min Deng from the College of Architecture and Environment at Sichuan University in China, was recently published in the journal “Advanced Science” (which translates to “Advanced Science” in English).
The team fabricated a mixed-matrix CMS (MMCMS) membrane using a palladium-doped carboxyl-functionalized UiO-66 (Pd/UiO66-COOH) embedded in a polyimide (PI) matrix. This innovative design addresses key challenges in gas separation, particularly for hydrogen (H2) and carbon dioxide (CO2).
“Our approach leverages the decomposition of carboxyl groups to create abundant micropores while enhancing the stability of the carbon framework,” Deng explained. This dual action mitigates the collapse of micropores during carbonization, significantly improving H2 and CO2 permeability and membrane stability.
The inclusion of palladium nanoparticles plays a pivotal role in the membrane’s performance. The synergistic effects of decarboxylation-induced thermally cross-linking and the catalytic graphitization effects of Pd nanoparticles facilitate the formation of more ordered Langmuir domains and narrow carbon interlayer spacing. This enhances molecular sieving effects and provides abundant H2 adsorption sites, facilitating the transport of H2 gases.
The PI/Pd-UiO66-COOH-5-550 MMCMS membrane demonstrated exceptional H2 permeability of 9134.6 Barrer, with a H2/CH4 selectivity of 118.5. This performance exceeds the latest Robeson upper bound, a benchmark in membrane gas separation technology. Additionally, the membrane showed remarkable aging resistance, retaining over 90% of its initial H2 and CO2 permeability after a 21-day long-term stability test.
The implications for the energy sector are profound. Efficient gas separation is crucial for various industrial processes, including natural gas purification, hydrogen recovery, and carbon capture and storage. The development of this advanced CMS membrane could lead to more energy-efficient and cost-effective solutions for these applications.
“This research opens up new possibilities for designing high-performance membranes for gas separation,” Deng noted. “The enhanced permeability and selectivity, along with the improved stability, make this membrane a promising candidate for industrial applications.”
As the world continues to seek sustainable energy solutions, advancements in gas separation technologies will play a vital role. The work of Deng and his team represents a significant step forward, offering a glimpse into the future of energy-efficient and environmentally friendly industrial processes.