Pyrazine-Fused Porous Graphitic Framework-Based Mixed Matrix Membranes for Enhanced Gas Separations

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Membrane separations offer energy-efficient alternatives to traditional thermal processes.
• Mixed matrix membranes (MMMs) are explored for advanced gas separations, but optimal nanofillers are challenging to identify.
• Overcoming the Robeson permeability-selectivity upper bounds is crucial for improving membrane performance.

Purpose of the Study:

• To develop novel mixed matrix membranes (MMMs) using pyrazine-fused crystalline porous graphitic frameworks (PGFs) as nanofillers.
• To evaluate the performance of PGF-based MMMs for hydrogen/methane and carbon dioxide separations.
• To demonstrate an effective strategy for creating high-performance MMMs that exceed current separation benchmarks.

Main Methods:

• Fabrication of mixed matrix membranes incorporating pyrazine-fused crystalline porous graphitic frameworks (PGFs).
• Testing of MMMs for gas permeability and selectivity, specifically for H₂/CH₄ and CO₂ separation.
• Comparison of PGF-based MMM performance against pristine membranes and established upper bounds (Robeson plots).

Main Results:

• PGF-based MMMs at 6 wt % loading surpassed the H₂/CH₄ Robeson upper bound.
• The MMMs demonstrated significant CO₂ separation performance, nearing the CO₂ Robeson upper bounds.
• Gas permeability increased by over 120% compared to pristine membranes, with maintained selectivity.
• The crystallinity of the nanofiller was identified as a critical factor for high performance.

Conclusions:

• Pyrazine-fused crystalline porous graphitic frameworks (PGFs) are effective nanofillers for high-performance mixed matrix membranes.
• The developed MMMs offer a viable pathway for energy-efficient gas separations, exceeding current benchmarks.
• The findings provide design principles for advanced membrane materials compatible with industrial manufacturing.