Investigation of an electrodeionization system for the removal of low concentrations of ammonium ions

Ammonium Removal from Domestic Wastewater Using Selective Battery Electrodes

“…While biological processes are the most common approach for ammonium removal, other technologies are being developed with the purpose of ammonium separation and recovery from wastewater, not only to avoid its release but also to enable its reuse. For example, several absorbents can be used for ammonium removal by ion exchange, but these approaches require salty brines to regenerate absorbents for further removal of ammonium in subsequent cycles. − Although the use of an ion exchange membrane can avoid the need for regeneration, the selectivity of the membrane for ammonium versus other cations is often low or unknown. − Ammonium can be removed from water through its conversion into volatile ammonia by raising the solution pH using chemicals or electrochemical systems and, then, its removal using stripping towers or membrane contactors. − These approaches can capture ammonium into valuable salts, such as (NH 4 ) 2 SO 4 , but raising and lowering solution pH can be expensive. Bioelectrochemical systems have also been proposed for ammonium recovery from wastewaters based on using the electrical power produced by microorganisms degrading organic matter in the wastewater; however, rates of ammonium separation are limited by the low current densities the bacteria produce, and removal is not selective for ammonium. − …”

Concentration and purification of chromate from electroplating wastewater by two-stage electrodialysis processes

“…Thus, it is significant to develop an effective and economic process to recover chromate in the manufacturing process for both economic and environmental purposes. Electrodialysis (ED) is a membrane separation process based on the selective migration of aqueous ions through ion-exchange membranes under electrical driving forces, and it has been commercially used for desalination, wastewater treatment and electrolyte separation for many different synthetic water [1][2][3][4][5][6][7][8][9] and wastewater [10][11][12][13][14]. Several studies have also reported for concentrating chromium species using ED [10,11,15].…”

Ammonia removal from fertilizer plant effluents by a coupled electrostatic shielding based electrodialysis / electrodeionization process

“…It uses electrically active media and an electrical potential to cause ion transport and may be operated batch wise, or continuously. Continuous electrodeionization processes such as electrodialysis (Gain et al, 2002;Yang et al, 2008;Mondor et al, 2008) and filled cell electrodialysis or otherwise called continuous electrodeionization (Spiegel et al, 1999) comprise alternating permselective cation exchange membranes and anion exchange membranes, which under the influence of the electric field allow only cations or only anions respectively to permeate their mass and simultaneously retain coions so that diluate and concentrate compartments are created and deionization occurs.…”