Facilitating CO₂ Transport Across Mixed Matrix Membranes Containing Multifunctional Nanocapsules

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Mixed matrix membranes (MMMs) are crucial for gas separation, but improving CO2 separation performance while overcoming the trade-off effect remains challenging.
• Designing multifunctional fillers is essential for enhancing CO2 separation efficiency in MMMs.

Purpose of the Study:

• To fabricate Pebax-based MMMs incorporating nanocapsules (NCs) with abundant carboxylic acid groups.
• To enhance CO2 separation performance by creating favorable microenvironments for CO2 transport channels within the MMMs.

Main Methods:

• Incorporation of nanocapsules (NCs) into a Pebax matrix to form MMMs.
• Utilizing the unique physical and chemical properties of NCs to construct CO2 transport channels.
• Evaluating CO2 separation performance using both facilitated transport and solution-diffusion mechanisms.

Main Results:

• MMMs doped with 20 wt% NCs surpassed the 2008 Robeson upper bound for CO2/CH4 and CO2/N2 separation.
• Achieved a 362% enhancement in CO2 permeability (1431 ± 35 Barrer) compared to the pure membrane.
• Increased CO2/CH4 selectivity by 44% (46 ± 1.4) and CO2/N2 selectivity by 23% (69 ± 2.7).

Conclusions:

• The developed NC-based MMMs offer an ingenious strategy for significantly enhancing gas permselectivity.
• The nanocapsule structure provides an effective approach to create efficient CO2 transport channels, improving separation performance.
• This work presents a promising pathway for developing high-performance membranes for CO2 capture and separation applications.