Poly(ionic liquid)-Based charge and size selective loose nanofiltration membrane for molecular separation

Separation of chemicals using membranes in smaller size regimes is a much-complicated process. An ideal membrane for molecular separation should be more hydrophilic with well-defined pore sizes for ensuring the selectivity to give a maximum solvent flux. Here, we report a poly(itaconic acid-co-styrene-co-sulfobetaine vinylimidazole) (PIL)/PSf blend selective filtration membrane with nanochannels for superior molecular separation. FESEM images showed asymmetrical membrane structure with a dense upper layer on the hallow spherical sphere, though contact angle measurements reported improved membrane hydrophilicity. Newly developed loose nanofiltration membranes showed a superior removal performance of synthetic dyes based on their size and charge, such as congo red (2.5 × 0.7 nm² size, 99%) and Eriochrome Black T (1.5 × 0.8 nm² sizes, 99%). The passage of methyl orange (1.1 × 0.4 nm²) demonstrating an excellent molecular separation capability due to their stable networks of interconnected nanochannel and thin selective layer. The overall results are promising and paving the way for environmental friendly and energy-efficient separation of chemicals through membranes in industrial applications.