An Innovative Surface Modification Technique for Antifouling Polyamide Nanofiltration Membranes

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Organic fouling remains a significant challenge in thin film composite (TFC) nanofiltration (NF) membranes, reducing their efficiency and lifespan.
• Existing surface modification methods often involve harsh chemicals or complex procedures, limiting their practical application.

Purpose of the Study:

• To develop a novel, eco-friendly surface coating technique for TFC NF membranes.
• To mitigate organic fouling while preserving or enhancing membrane permselectivity.
• To evaluate the scalability and cost-effectiveness of the proposed method.

Main Methods:

• Mist-based interfacial polymerization was employed to create a spot-like polyester (PE) coating on polyamide (PA) TFC membranes.
• Different concentrations of sulfonated kraft lignin (SKL) and trimesoyl chloride (TMC) were used in the coating process.
• Membrane surface properties (zeta potential, roughness) and performance (flux recovery ratio, salt rejection) were analyzed before and after coating.

Main Results:

• PE-coated membranes exhibited enhanced negative surface charge and reduced surface roughness compared to the control PA membrane.
• The membrane coated with 7 wt % SKL achieved a 90% flux recovery ratio during Bovine Serum Albumin (BSA) filtration, a 15% improvement over the control.
• Coated membranes demonstrated stable separation performance and robustness over 40 hours of filtration.

Conclusions:

• The developed mist-based interfacial polymerization is an effective and sustainable method for surface modification of TFC NF membranes.
• The PE coating significantly improves fouling resistance without compromising separation performance.
• The technique is scalable, cost-effective, and offers a promising solution for advanced membrane applications.