Polymeric membranes for aromatic/aliphatic separation processes.

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Technology

Background:

• Membrane-based separation is crucial for industrial processes.
• Polymeric membranes often suffer from swelling and reduced selectivity in aromatic/aliphatic separations.
• 6FDA-based copolyimides offer potential for improved membrane performance.

Purpose of the Study:

• To investigate the pervaporation properties of 6FDA-based copolyimide membranes for benzene/cyclohexane mixture separation.
• To synthesize and characterize novel copolyimides with tailored structures for enhanced separation.
• To optimize crosslinking strategies to mitigate swelling and improve selectivity.

Main Methods:

• Synthesis of 6FDA-based copolyimides using 4MPD, 6FpDA, and DABA monomers.
• Crosslinking of copolyimide membranes using varied agents and methods.
• Sorption experiments with aromatic (benzene, toluene, ethylbenzene) and aliphatic (cyclohexane, etc.) solvents at 60°C.
• Pervaporation experiments using benzene/cyclohexane mixtures across the full concentration range at 60°C.

Main Results:

• Crosslinked copolyimide membranes demonstrated excellent chemical resistance.
• Significantly reduced swelling behavior was observed in the crosslinked membranes.
• Higher selectivity for aromatic/aliphatic separation was achieved compared to conventional materials.

Conclusions:

• Crosslinked 6FDA-based copolyimide membranes are highly effective for benzene/cyclohexane separation.
• The developed membranes overcome common limitations of polymeric membranes, such as swelling.
• These materials represent a promising advancement in membrane technology for aromatic/aliphatic separations.