Tailoring Nanofiltration Membranes by Incorporating Zwitterionic Quaternary Ammonium Terpolymer to Enhance...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Nanofiltration membrane design is crucial for effective water treatment.
• Aliphatic diethylenetriamine membranes offer unique properties but require selectivity tuning.
• Dye and salt separation presents a significant challenge in water purification.

Purpose of the Study:

• To synthesize and graft a novel cationic/zwitterionic terpolymer onto aliphatic diethylenetriamine nanofiltration membranes.
• To enhance water flux and salt permeability while maintaining high dye rejection.
• To evaluate the performance of these modified membranes for desalination and dye removal.

Main Methods:

• Rational synthesis of a DADMAC-co-DAMAPS-co-DADA terpolymer.
• In-situ grafting of the terpolymer onto the polyamide active layer via interfacial polymerization.
• Characterization of membrane performance in terms of water flux, salt permeability, and dye rejection.

Main Results:

• A 5.8-fold increase in water flux was achieved with the modified membranes.
• Outstanding rejection rate of ~99.9% for Eriochrome black T (EBT) dye was maintained.
• Enhanced permeability for various salts (NaCl, MgCl2, Na2SO4, MgSO4) was observed.
• Increased membrane hydrophilicity and improved stability under working conditions.

Conclusions:

• The developed terpolymer-modified aliphatic diethylenetriamine membranes show great potential for desalination.
• Tuning the active layer with zwitterionic moieties enhances salt permeability and dye rejection.
• These membranes are valuable for environmental applications, particularly in textile wastewater treatment.