Cosolvent-Driven Interfacial Polymerization for Superior Separation Performance of Polyurea-Based Pervaporation...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Thin-film composite (TFC) membranes are crucial for separation processes.
• Interfacial polymerization is a key method for TFC membrane fabrication.
• Dehydration of organic solvents like tetrahydrofuran (THF) is industrially significant.

Purpose of the Study:

• To fabricate a TFC polyurea membrane for aqueous THF dehydration.
• To investigate the effect of alcohol cosolvents on membrane properties and performance.
• To optimize fabrication conditions for enhanced separation.

Main Methods:

• Interfacial polymerization of polyethyleneimine and m-xylene diisocyanate on a modified polyacrylonitrile (mPAN) substrate.
• Addition of alcohol cosolvents (methanol, ethanol, isopropanol, tert-butanol) to the aqueous monomer phase.
• Characterization using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FESEM), and contact angle measurements.
• Pervaporation experiments to evaluate separation performance.

Main Results:

• Polyurea layer formation confirmed by ATR-FTIR.
• Membrane morphology and hydrophilicity remained largely unchanged with cosolvent addition.
• The TFC membrane fabricated with 10 wt.% ethanol exhibited superior performance: 1006 ± 103 g·m^-2·h^-1 flux and 98.8 ± 0.3 wt.% water in permeate for 90 wt.% THF feed at 25 °C.
• Ethanol induced loosening and cross-linking in the polyurea layer during formation.

Conclusions:

• Ethanol is an effective cosolvent for enhancing TFC polyurea membrane performance in THF dehydration.
• Optimal fabrication conditions include 10 wt.% ethanol, 50 °C curing temperature, and 30 min curing time.
• The developed membrane shows promise for efficient dehydration of aqueous THF solutions.