Charge-neutral nanoporous membrane enables one-step electrodialytic dye/salt fractionation

Sustainable high-salinity dye-containing wastewater management demands a paradigm shift from conventional pollutant removal to circular resource recovery. Herein, we report a bio-inspired, electro-driven nanoporous membrane as a high-performance anion-conducting platform for one-step electrodialytic separation. Through co-deposition of dopamine and polyethyleneimine, we achieved precise sub-nanometer regulation of membrane properties, including tunable pore sizes (from 1.00 nm to 0.51 nm), near-zero surface charge (from −10.2 mV to −0.9 mV), and reduced electrical resistance (from 6.15 to 3.31 Ω·cm 2 ), enabling an optimal balance between dye rejection and ion transport. Unlike conventional anion exchange membranes that are prone to rapid fouling, our charge-neutral membrane leverages enhanced steric hindrance and minimized electrostatic attraction to achieve a marked selectivity for one-step steady electrodialytic dye/salt fractionation, demonstrating 99.2% desalination efficiency and 99.6%-99.7% high dye recovery with negligible fouling over nine consecutive cycles. This study establishes a facile and scalable strategy for engineering high-performance ion-conducting membranes, offering a promising approach for sustainable valorization of complex industrial waste streams.