Controlled Secondary Growth of CAU-1-NH₂ Membranes with Improved CO₂ Separation Performance

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Metal-organic frameworks (MOFs) offer tunable structures for gas separation.
• Energy-efficient gas separation membranes are crucial for industrial applications.

Purpose of the Study:

• Fabricate CAU-1-NH2 membranes on porous substrates.
• Investigate the impact of synthesis parameters on membrane performance.
• Evaluate the gas separation capabilities of CAU-1-NH2 membranes.

Main Methods:

• Seeded growth method for CAU-1-NH2 membrane fabrication.
• Scanning electron microscopy and confocal fluorescence microscopy for structural analysis.
• Single-gas and mixed-gas permeation tests.
• Grand canonical Monte Carlo (GCMC) simulations.

Main Results:

• Optimized CAU-1-NH2(B) membrane exhibited a continuous, low-defect structure.
• Achieved high H2, CO2, N2, and CH4 permeances.
• Demonstrated ideal CO2/N2 selectivity of 19.4 and CO2/CH4 selectivity of 17.6.
• Mixed-gas tests showed CO2/N2 separation factors up to 89.2.
• GCMC simulations highlighted CO2 competitive adsorption.

Conclusions:

• CAU-1-NH2 membranes show excellent potential for CO2 separation.
• Synthesis parameters significantly influence membrane morphology and performance.
• Competitive adsorption is key to the observed separation behavior.