Polarity reversal and double reversal electrodeionization apparatus and method

Electrodeionization apparatus comprising:

• a plurality of compartments comprising at least one ion-concentrating compartment positioned adjacent to at least one ion-depleting compartment, the ion-concentrating and ion-depleting compartments each containing an ion-exchange material and the plurality of compartments being defined, in part, by spaced, alternating anion-permeable membranes and cation-permeable membranes;
• a first electrode on a first side of the plurality of compartments and in electrical communication therewith;
• a second electrode on a second side of the plurality of compartments and in electrical communication therewith;
• an electrical source in electrical communication with the first and second electrodes, which, in combination with the electrodes and the plurality of compartments, defines an electrical circuit;
• a forward flow fluid circuit connecting a source of a first fluid stream to a first port of the ion-concentrating compartment to provide the first fluid stream flowing through the ion-concentrating compartment in a first direction, and connecting a source of a second fluid stream to a first port of the ion-depleting compartment, to provide the second fluid stream flowing through the ion-depleting compartment in a first direction;
• and
• a reverse flow fluid circuit connecting the source of the first fluid stream to a second port of the ion-concentrating compartment to provide the first fluid stream flowing through the ion-concentrating compartment in a second direction opposite the first direction.

Electrodeionization apparatus comprising:

• a plurality of compartments having at least one ion-concentrating compartment positioned adjacent to at least one ion-depleting compartment, the ion-concentrating and ion-depleting compartments each containing an ion-exchange material and the plurality of compartments being defined in part by spaced, alternating anion-permeable membranes and cation-permeable membranes;
• a first electrode on a first side of the plurality of compartments and in electrical communication therewith;
• a second electrode on a second side of the plurality of compartments and in electrical communication therewith;
• an electrical source in electrical communication with the first and second electrodes, which, in combination with the electrodes and the plurality of compartments, defines an electrical circuit;
• a first fluid circuit connecting a source of a first fluid stream having an ionic concentration to the ion-concentrating compartment, and connecting a source of a second fluid stream having an ionic concentration to the ion-depleting compartment, the first fluid circuit including a recirculation path arranged to recirculate fluid flow from an exit of the ion-concentrating compartment to an entrance thereof;
• and
• a liquid/gas interface area in the recirculation path.

Electrodeionization apparatus comprising:

• a plurality of compartments comprising at least one ion-concentrating compartment positioned adjacent to at least one ion-depleting compartment, the ion-concentrating and ion-depleting compartments each containing an ion-exchange material and the plurality of compartments being defined in part by spaced, alternating anion-permeable membranes and cation-permeable membranes;
• a first electrode on a first side of the plurality of compartments and in electrical communication therewith;
• a second electrode on a second side of the plurality of compartments and in electrical communication therewith;
• an electrical source in electrical communication with the first and second electrodes, which, in combination with the electrodes and the plurality of compartments, defines an electrical circuit;
• a first fluid circuit connecting a source of a first fluid stream having an ionic concentration to the ion-concentrating compartment, and connecting a source of a second fluid stream having an ionic concentration to the ion-depleting compartment, the first fluid circuit including a recirculation path arranged to recirculate fluid flow from an exit of the ion-concentrating compartment to an entrance thereof;
• and
• a source of species selected from the group consisting of chemical species, biological species, and mixtures thereof in fluid communication with the recirculation path.