Patent ID: 7704361

Claim:
An ionic transfer apparatus comprising a plurality of chambers including at least a) an electrode chamber at each end of the apparatus and bounded by an end membrane, each electrode chamber containing an electrode, each electrode having opposite polarity from the electrode in the electrode chamber at the opposite end of the apparatus, the end membranes are selected from the group consisting of cation exchange membranes, anion exchange membranes, and neutral membranes; b) a first and a second ionic transfer chamber, each of the ionic transfer chambers being adjacent to one of the end membranes and having a first and a second ionic membrane spaced apart from said end membrane, each of the first and second ionic membranes having a different ionic property compared to each end membrane; c) either no additional ionic membrane or, optionally, an even-number of supplemental ionic membranes disposed between said first and second ionic membranes and spaced apart from said first and second ionic membranes and from each other to form at least one additional ionic transfer chamber between said first and second ionic transfer chambers, the first and second ionic membranes, and supplemental ionic membranes, if present, are either all cation exchange membranes or all anion exchange membranes; and d) means for reversing the polarities of said electrodes during operation of said apparatus; e) a first liquid from which ions are to be transferred contained in the at least one additional ionic transfer chamber, a second liquid into which ions are to be transferred contained in the first and second ionic transfer chambers, wherein when a plurality of additional ionic transfer chambers are present between the first and second ionic transfer chambers, the additional ionic chambers alternately contain the first liquid and the second liquid such that no two adjacent ionic transfer chambers contain the same liquid; f) means for circulating the second liquid from the first and second ionic transfer chambers and additional ionic chambers, if present, into a bipolar electrodialysis cell; and g) a bipolar electrodialysis cell for transferring ions from the second liquid into a third liquid.