Patent ID: 8496797

Claim:
Method of reducing ion concentration in an influent solution comprising: in a deionization phase of operation, feeding said influent to a membraneless electrodeionization (EDI) stack comprising layers of porous anion exchange materials (AIX) and cation exchange materials (CIX) interposed between a cathode and an anode, a plurality of said layers being positioned in alternating AIX and CIX layer pairs defining an interfacial area between each said AIX and CIX layer in each pair, passing said influent over said AIX and CIX whereby said ion concentration is reduced via ion exchange with said AIX and CIX; collecting deionized product from said EDI stack; and in a regeneration phase of operation, imparting a voltage across said electrodes and feeding flush water as influent to said EDI stack and across said AIX and CIX materials, whereby water splitting occurs along at least one of said interfacial areas resulting in formation of H + and OH − ions which migrate to and regenerate said AIX and CIX materials, and recovering a waste stream as effluent, said deionization phase and said regeneration phase alternating in time.