Regenerating end-of-life membranes for enhanced sustainability and unexpected performance

Abstract Membrane technologies are widely adopted in water purification, gas separation, resource recovery and chemical production. However, membranes eventually reach their end-of-life (EOL) due to structural degradation and irrecoverable fouling, leading to incineration or landfilling which contradicts the sustainability and circular economy principles. Here we present a strategy to regenerate EOL membranes through dissolution in organic solvent followed by re-casting. The regenerated membrane exhibits more than fivefold higher water permeance with improved pollutant rejection compared to the EOL membrane, and even outperforms membrane fabricated from pristine polymer powders. This enhancement is attributed to the integration of residual foulants as pore-forming agents and hydrophilic additives. Moreover, the reduced entanglement density of EOL membrane improves its compatibility with solvent and foulants, enabling the formation of a dense separation layer in the regenerated membrane. This strategy achieves 38.4% lower CO 2 -eq emissions and 75.7% cost reduction, advancing sustainability and circularity of the membrane industry.