Continuous Covalent Organic Framework Membranes with Ordered Nanochannels as Tunable Transport Layers for Fast...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Technology

Background:

• Developing energy-efficient separation membranes is crucial for biofuel recovery.
• Designing polymeric membranes with controlled nanochannels for efficient alcohol transport remains a challenge.

Purpose of the Study:

• To demonstrate highly crystalline covalent organic framework (COF) membranes for efficient butanol/water separation.
• To investigate the relationship between membrane thickness and mass-transfer coefficient for optimizing separation performance.

Main Methods:

• Fabrication of COF membranes with tunable thickness by controlling monomer concentration and molar ratio.
• Surface modification with poly(dimethylsiloxane) to create defect-free and hydrophobic membranes.
• Evaluation of membrane performance using pervaporation for n-butanol/water separation.

Main Results:

• Achieved exceptional flux (18.8 kg m⁻² h⁻¹) and pervaporation separation index (217.7 kg m⁻² h⁻¹) for 5 wt% n-butanol/water separation.
• Demonstrated defect-free, hydrophobic COF membranes with ordered nanochannels.
• Observed an inverse relationship between COF membrane thickness and butanol mass-transfer coefficient.

Conclusions:

• Crystalline polymeric membranes with high-density nanopores show great potential for biofuel recovery.
• Tunable nanochannel design in COF membranes enables efficient and energy-saving bioalcohol separations.
• Controlled membrane thickness is critical for enhancing alcohol transport and separation efficiency.