Patent ID: 7604725

Claim:
An electrochemical device comprising: a first compartment comprising electroactive media that is substantially free of anion-exchange resin and is bounded by a first anion-selective membrane and a second anion-selective membrane; a second compartment disposed adjacent the first compartment, the second compartment defined at least partially by a first cation-selective membrane and the first anion-selective membrane, and the second compartment comprising a first mixed bed of cation exchange resin and anion exchange resin; a first depleting compartment disposed adjacent the second compartment, the first depleting compartment defined at least partially by the first cation-selective membrane and a third anion-selective membrane; a concentrating compartment disposed adjacent the first depleting compartment, the concentrating compartment defined at least partially by the third anion-selective membrane; a second depleting compartment disposed adjacent the first compartment, the second depleting compartment defined at least partially by the second anion-selective membrane and a second cation-selective membrane; and a cathode compartment fluidly connected downstream from the first compartment.