Precise Separation of Complex Ultrafine Molecules through Solvating Two-Dimensional Covalent Organic Framework...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Isoporous nanomaterials are crucial for molecular sieving in sustainable membrane technologies.
• Covalent organic frameworks (COFs) offer tunable pore structures but face challenges due to structural discrepancies.
• Developing COF membranes for precise molecular separations remains an active research area.

Purpose of the Study:

• To engineer 2D COF membranes with solvating pores for high-selectivity molecular sieving.
• To investigate the dynamic structural response of COF membranes to solvent exposure.
• To demonstrate the application of these membranes in separating complex mixtures.

Main Methods:

• Fabrication of pore-to-pore-aligned 2D COF membranes.
• Characterization of membrane structure and interlayer dynamics using solvent stimuli.
• Evaluation of molecular sieving performance for binary and trinary mixtures.
• Assessment of membrane stability and operational longevity.

Main Results:

• The COF membranes exhibit reversible interlayer expansion and intralayer shift upon solvent exposure.
• Solvent-induced dynamic deformation reduces pore aperture, enhancing molecular selectivity.
• The membranes achieved significantly improved selectivity for complex ultrafine molecules compared to conventional COF membranes.
• Exceptional membrane stability was demonstrated with over 3000 hours of reliable operation.

Conclusions:

• Structurally oriented 2D COF membranes with dynamic solvating pores enable superior molecular sieving.
• These membranes offer a robust and stable platform for separating valuable chemicals, including active pharmaceutical ingredients.
• The findings pave the way for advanced membrane applications in chemical enrichment and purification.