Turning Microstructure in Block Copolymer Membranes: A Facile Strategy to Improve CO₂ Separation Performance

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Global climate change necessitates advanced materials for efficient carbon dioxide (CO2) capture.
• Membrane technology is crucial for gas separation, requiring high CO2 permeability and selectivity.
• Pebax 2533 membranes show potential but require performance enhancement for industrial carbon capture applications.

Purpose of the Study:

• To develop a simple and effective technique to improve the gas separation performance of Pebax 2533 membranes.
• To investigate the impact of non-solvent-induced microstructure rearrangement (MSR) on membrane properties.
• To assess the long-term stability and applicability of the MSR technique to various membrane configurations.

Main Methods:

• A non-solvent-induced microstructure rearrangement (MSR) technique was employed, immersing Pebax 2533 membranes in amino acid salt solutions.
• The MSR technique was applied to both neat Pebax 2533 membranes and thin-film composite (TFC) membranes (Pebax 2533/PVC and Pebax 2533/PAN).
• Gas separation performance (CO2 permeability and selectivity) and long-term stability were evaluated.

Main Results:

• The optimized Pebax 2533-GlyK 10 wt.% membrane achieved a 4.5-fold increase in CO2 permeability (1180 Barrer) without sacrificing CO2/N2 selectivity.
• The MSR-treated membrane demonstrated stable performance for nearly 500 days.
• Both hollow fiber (HF) and flat-sheet TFC membranes showed significantly enhanced CO2 permeance after MSR treatment with DI water.
• Characterization confirmed minimal changes in chemical-physical properties post-MSR.

Conclusions:

• Non-solvent-induced MSR is a highly effective and simple technique for enhancing the CO2 separation performance of Pebax-based membranes.
• The MSR method offers a promising pathway for developing next-generation membranes for efficient carbon capture.
• The technique demonstrates excellent long-term stability and broad applicability to different membrane types.