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Updated: May 10, 2026

Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Implication of diffusion and significance of anodic pH in nitrogen-recovering microbial electrochemical cells
Sakineh Haddadi1, Elsayed Elbeshbishy, Hyung-Sool Lee
1Department of Environmental Health, Tehran University of Medical Sciences, Tehran, Iran.
Abstract:
Microbial electrochemical cells (MXCs) using cation and anion exchange membranes (CEM and AEM) were tested in batch mode for ammonium recovery. Experimental results showed superior ammonium recovery of 61% in CEM-MXC. Migration effect accounted for 61% of the total ammonium recovery in CEM-MXC where other ammonium ions (39%) were transferred by diffusion. Current density was significant for improving the recovery rate of ammonium nitrogen, but proton accumulation deteriorated current density in CEM-MXC. The dissolution of ammonia hydrolyzed by urea produces hydroxyl ions, which can neutralize protons in the anode and maintain high current density in CEM-MXC. However, anodic pH increased over 9 at high current density (>2A/m(2)) in CEM-MXC fed by urea, which indicates that the rate of ammonia dissolution becomes faster than proton accumulation rate at high current density. Balancing proton-accumulating rate with ammonia dissolution rate in the anode is significant for improving ammonium recovery in CEM-MXC.
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