Green β-cyclodextrin interlayered crumpled polyamide membranes for effective desalination

The use of sacrificial layers on porous substrates has proven to be an effective approach for regulating the interfacial polymerization process and shaping the structure of polyamide (PA) nanofiltration (NF) membranes, thereby addressing the trade-off between permeability and selectivity. However, the synthesis and removal of traditional interlayer materials often require harsh chemicals, generating hazardous waste and posing environmental risks. In this study, we utilized green, non-toxic, and biodegradable β-cyclodextrin (β-CD) nanosheets as an interlayer in the interfacial polymerization process. These nanosheets were subsequently dissolved in water to create crumpled polyamide nanofiltration membranes, avoiding the use of toxic chemicals and significantly reducing environmental impact. With an optimal β-CD loading of 1.0 mg/cm 2 , the resulting membrane exhibited a remarkable water flux of 13.4 LMH/bar, reflecting a 330 % improvement over the reference membrane, along with a 97.9 % Na₂SO₄ rejection. This performance enhancement is linked to enhanced surface hydrophilicity, a higher surface charge density, and a thinner PA layer with an expanded surface area. The membrane also exhibited excellent antifouling properties and long-term separation performance. This innovative, eco-friendly approach represents a significant advancement in membrane technology, providing a sustainable solution for enhanced nanofiltration membrane performance in water treatment applications.