Biphenyl-Based Covalent Triazine Framework/Matrimid^® Mixed-Matrix Membranes for CO₂/CH₄ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Carbon dioxide (CO2)/methane (CH4) separation is crucial for biogas upgrading and natural gas sweetening.
• Mixed-matrix membranes (MMMs) offer enhanced separation efficiency by incorporating filler materials into polymer matrices.

Purpose of the Study:

• To investigate the performance of covalent triazine framework CTF-biphenyl as a filler in a polyimide matrix for CO2/CH4 separation.
• To evaluate the impact of CTF-biphenyl loading on membrane permeability and selectivity.

Main Methods:

• Fabrication of mixed-matrix membranes (MMMs) using CTF-biphenyl filler and Matrimid® polyimide matrix.
• Testing MMMs with varying filler loadings (8, 16, and 24 wt%) for CO2/CH4 mixed-gas separation.

Main Results:

• A mixed-matrix membrane with 16 wt% CTF-biphenyl loading exhibited more than double the CO2 permeability compared to the pure polyimide membrane.
• The high CO2/CH4 selectivity characteristic of the Matrimid® polymer was maintained.

Conclusions:

• CTF-biphenyl is an effective filler material for enhancing CO2/CH4 separation in mixed-matrix membranes.
• The developed MMMs show significant potential for applications in biogas upgrading and natural gas sweetening.