Green Synthesis of Cellulose Acetate Mixed Matrix Membranes: Structure-Function Characterization

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Membrane technology is crucial for gas separation but faces environmental challenges due to toxic solvents and oil-based polymers.
• A shift towards circular economy principles necessitates sustainable alternatives in membrane fabrication.
• Biopolymers, green solvents, and surfactant-free fillers offer eco-friendly solutions.

Purpose of the Study:

• To promote environmentally sustainable and low-toxicity alternatives in membrane fabrication.
• To introduce cellulose acetate (CA) as a biopolymer and dimethyl carbonate (DMC) as a green solvent for membrane preparation.
• To investigate the gas separation performance of mixed matrix membranes incorporating inorganic fillers.

Main Methods:

• Utilized Hansen Solubility Parameters to confirm polymer-solvent affinity.
• Characterized pure CA and mixed matrix membranes (hydrophilicity, thermal stability, mechanical resistance, ATR-FTIR, SEM).
• Evaluated gas separation performance using single gas permeability (N2, CH4, CO2) and analyzed structure-property relationships with phenomenological models.

Main Results:

• Developed novel mixed matrix membranes using CA, DMC, and inorganic fillers (Zeolite-A, ETS-10, AM-4, ZIF-8) without toxic solvents.
• Observed significant reductions in CO2 permeability after conditioning (e.g., 12,600 Barrer to 740 Barrer).
• Reported changes in selectivity (e.g., 24% reduction in CO2/CH4, 24% increase in CO2/N2) influenced by filler type and conditioning.

Conclusions:

• Cellulose acetate and dimethyl carbonate offer a sustainable alternative for membrane fabrication.
• The prepared mixed matrix membranes exhibit tunable gas separation properties.
• Further research is needed to fully understand the interactions between the green solvent, matrix, and fillers influencing gas transport.