Biopolymer-Based Mixed Matrix Membranes (MMMs) for CO₂/CH₄ Separation: Experimental and Modeling Evaluation.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Membrane technology is crucial for CO2 separation but faces sustainability challenges in fabrication.
• Developing eco-friendly materials aligns with circular economy principles for sustainable membrane processes.
• Chitosan (CS)-based membranes offer a biodegradable alternative for gas separation applications.

Purpose of the Study:

• To fabricate and evaluate chitosan-based mixed matrix membranes for CO2/CH4 separation.
• To enhance membrane performance using non-toxic ionic liquids (IL) and nanoporous silicates (AM-4, UZAR-S3).
• To correlate membrane properties with process performance for optimized CO2 and CH4 recovery and purity.

Main Methods:

• Chitosan (CS) mixed matrix thin layers coated onto polyethersulfone (PES) supports.
• Incorporation of 1-Ethyl-3-methylimidazolium acetate ionic liquid (IL) and/or AM-4 and UZAR-S3 silicates into the CS matrix.
• Experimental evaluation of CO2/CH4 separation performance at varying feed compositions.
• Process simulation using Aspen Custom Modeler to validate performance and correlate membrane properties.

Main Results:

• Chitosan-based membranes with IL and AM-4 showed superior CO2/CH4 separation, purity, and recovery.
• Enhanced hydrophilicity, CO2 adsorption, and mechanical robustness contributed to improved performance.
• The 10 wt.% AM-4:IL-CS/PES composite membrane performance matched or exceeded a commercial reference membrane.
• Membranes prepared without costly organic surfactants demonstrated significant potential.

Conclusions:

• Chitosan-based mixed matrix membranes with IL and AM-4 are viable for sustainable CO2/CH4 separation.
• The developed membranes offer comparable or superior performance to existing technologies.
• This research provides a pathway for renewable/biodegradable membranes and links material properties to process targets.