Parametric study of redox-mediated electrodialysis for ammonia treatment

Ammonium contamination in wastewater is a major environmental issue, causing eutrophication and the formation of fine particulate matter. Traditional treatment methods, such as biological processes and conventional electrodialysis, frequently encounter operational challenges and high energy requirements. This study introduces redox-mediated electrodialysis (redox-ED) as an energy-efficient and flexible alternative for ammonium removal and recovery. A comprehensive parametric investigation was conducted to assess the impact of initial feed channel concentrations (1–100 mM), applied voltages (0.6–1.2 V), linear velocities (0.625–5 cm/min), redox couple temperatures (4–70 °C), and feed pH levels (5.6–9.5) on system performance. The redox-ED system achieved an impressive ammonium flux of 95.39 g-NH 4 + /m 2 d and energy efficiency of 1.57 Wh/g-N under optimal conditions of 50 mM initial feed concentration, 1.2 V applied voltage, and 5 cm/min linear velocity. Notably, the system maintained high removal efficiency across a broad pH range, demonstrating its versatility for various wastewater treatment applications. Extended operation over 18 h resulted in over 92 % ammonium recovery. These findings highlight the potential of redox-ED technology as a robust and energy-efficient solution for addressing ammonium contamination in wastewater, offering valuable insights for its practical implementation. Schematics of Redox-Mediated Electrodialysis for Ammonia Treatment