Amine-Containing Membranes with Functionalized Multi-Walled Carbon Nanotubes for CO₂/H₂ Separation.

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Facilitated transport membranes offer potential for gas separation.
• Mixed-matrix membranes (MMMs) combine polymer properties with filler advantages.
• Enhancing membrane stability under high pressure is critical for industrial applications.

Purpose of the Study:

• To synthesize amine-containing MMMs with amino-functionalized multi-walled carbon nanotubes (AF-MWNTs) for CO2/H2 separation.
• To investigate the effect of AF-MWNTs on membrane performance and stability.
• To evaluate the potential of these membranes for high-pressure gas processing.

Main Methods:

• Synthesis of amine-containing MMMs incorporating AF-MWNTs.
• Gas separation performance testing at varying feed pressures (0.2 MPa and 1.5 MPa) and 107 °C.
• Assessment of membrane stability and resistance to compaction over 100 hours.

Main Results:

• The MMM with 10 wt.% AF-MWNTs achieved high CO2 permeability (3196 Barrers) and CO2/H2 selectivity (205) at 0.2 MPa.
• At 1.5 MPa, performance decreased (776 Barrers CO2 permeability, 31 CO2/H2 selectivity) due to carrier saturation.
• Membrane stability significantly improved, maintaining performance and thickness for 100 hours, demonstrating resistance to compaction.

Conclusions:

• AF-MWNTs act as effective reinforcing fillers, enhancing MMM stability and resistance to compaction.
• The synthesized MMMs exhibit performance exceeding theoretical upper bounds for CO2/H2 separation.
• These findings represent a significant step towards applying facilitated transport membranes in high-pressure gas processing, such as syngas purification.