Scalable regeneration of damaged polyamide membranes via self-assembled biomass coatings for sustainable water treatment

Thin-film composite polyamide (TFC-PA) membranes are widely used in water purification, yet oxidative and operational damage often drive premature disposal and replacement. This study presents a scalable two-step aqueous regeneration strategy that reconstructs damaged PA surfaces using a redox-triggered, lysozyme-derived biomass interlayer (BDI) followed by polyethyleneimine (PEI) functionalization. The BDI forms a cohesive proteinaceous priming nanofilm that restores surface continuity and provides multivalent anchoring sites for PEI, yielding an amine-rich, charge-governed interface. Applied to damaged nanofiltration membranes, the regenerated membranes achieve high Li⁺/Mg²⁺ selectivity (S _Li/Mg = 128.1) with Mg²⁺ rejection exceeding 99.5% while maintaining practical water transport. The strategy is further extended to end-of-life reverse osmosis (RO) elements, where regeneration recovers desalination performance with a water permeance of 3.5 ± 0.5 L m⁻² h⁻¹ bar⁻¹ and NaCl/MgCl₂ rejections of 92.8 ± 0.1% and 96.8 ± 0.5%, respectively, demonstrating competitive performance relative to a commercial NF benchmark. Long-term filtration in complex waters confirms enhanced fouling/scaling tolerance and regeneration-enabled recoverability after oxidative challenge via surface reconstruction. An element-level cost assessment estimates a chemical cost of $12.87 per 8-inch module, highlighting the potential for low-cost membrane reuse and reduced lifecycle impacts for sustainable water treatment.