Polyamide modified anion exchange membrane by interfacial polymerization for nitrate and phosphate salt separation

The separation and removal of nutrient salts from wastewater can realize environmental remediation, and resource recycling and utilization. Electrodialysis (ED) membrane separation technology can offer an effective and low-energy consumption alternative but requires selective separation of nutrient salts with rapid anions permeation rate. We fabricated selective anion exchange membranes (PA-ATG) with the polyamide (PA) surface modification of commercial ATG anion exchange membrane by interfacial polymerization (IP) method. The dense PA thin-film layer with high hydrophilicity and electronegativity facilitates nitrate/phosphate anions selectively permeating through the PA-ATG membrane. The PA-ATG membrane exhibited a NO 3 − anion permeation rate of 1.1 mol m −2  h −1 and good NO 3 − /HxPO 4 (3−x)- permselectivity of 2.02, which is ∼2.0 times higher than that of the pristine ATG membrane. Owing to the rigid aromatic crosslinking structure, and electrostatic and hydrogen-bonding multiple interfacial interaction, the as-prepared membrane PA-ATG showed good stable and efficient separation performance during ED process for the nutrient wastewater treatment.