Polarity reversal and double reversal electrodeionization apparatus and method

A method for purifying a fluid comprising:

• a) providing an electrodeionization apparatus comprising a plurality of compartments including 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, the compartments positioned between first and second electrodes in electrical communication with the compartments;
• b) establishing a first fluid stream through said at least one ion-concentrating compartment in a first direction and a second fluid stream through said at least one ion-depleting compartment in a first direction;
• c) energizing the electrodes by applying a first polarity to the first electrode and a second polarity to the second electrode to provide an electrical potential across the compartments, thereby establishing a depleted fluid stream exiting said at least one ion-depleting compartment and a concentrated fluid stream exiting said at least one ion-concentrating compartment, the depleted fluid stream having an ionic concentration lower than that of the second fluid stream;
• d) reversing the direction of flow of the first fluid stream through said at least one ion-concentrating compartment from the first direction to a second direction opposite the first direction;
• and
• e) recovering a depleted fluid product from said at least one ion-depleting compartment while the first fluid stream flows through said at least one ion-concentrating compartment in the second direction.

A method for purifying a fluid comprising:

• a) providing an electrodeionization apparatus comprising a plurality of compartments including 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, the compartments positioned between first and second electrodes in electrical communication with the compartments;
• b) establishing a first fluid stream having an ionic concentration through said at least one ion-concentrating compartment and an exit fluid stream having an ionic concentration exiting said at least one ion-concentrating compartment;
• c) recirculating the exit fluid stream so as to establish the exit fluid stream as the first fluid stream;
• and
• d) increasing the ionic concentration of the first fluid stream.

A method for purifying a fluid comprising:

• a) providing an electrodeionization apparatus comprising a plurality of compartments including 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, the compartments positioned between first and second electrodes in electrical communication with the compartments;
• b) establishing a first fluid stream having an ionic concentration through said at least one ion-concentrating compartment and a second a fluid stream having an ionic concentration through said at least one ion-depleting compartment;
• c) energizing the electrodes by applying a first polarity to the first electrode and a second polarity to the second electrode to provide an electrical potential across the compartments, thereby establishing a depleted fluid stream exiting said at least one ion-depleting compartment and a concentrated fluid stream exiting said at least one ion-concentrating compartment, the depleted fluid stream having an ionic concentration lower than that of the second fluid stream;
• d) increasing the ionic concentration of the first fluid stream;
• and
• e) converting said at least one ion-depleting compartment to at least one second ion-concentrating compartment and converting said at least one ion-concentrating compartment to at least one second ion-depleting compartment.

A method for purifying a fluid comprising:

• a) providing an electrodeionization apparatus comprising a plurality of compartments including 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, the compartments positioned between first and second electrodes in electrical communication with the compartments;
• b) establishing a first fluid stream having an ionic concentration through said at least one ion-concentrating compartment and a second fluid stream having an ionic concentration through said at least one ion-depleting compartment;
• c) energizing the electrodes by applying a first polarity to the first electrode and a second polarity to the second electrode to provide an electrical potential across the compartments and establish a depleted fluid stream exiting said at least one ion-depleting compartment and a concentrated fluid stream exiting said at least one ion-concentrating compartment, the depleted fluid stream having an ionic concentration lower than that of the second fluid stream;
• d) converting said at least one ion-depleting compartment to at least one second ion-concentrating compartment and converting said at least one ion-concentrating compartment to at least one second ion-depleting compartment by establishing the first fluid stream through said at least one second ion-concentrating compartment and establishing the second fluid stream through said at least one second ion-depleting compartment and reversing the polarity of the first and second electrodes;
• and
• e) reversing the direction of flow of the first fluid stream through said at least one second ion-concentrating compartment from the first direction to a second direction opposite the first direction, and recovering a depleted fluid product from said at least one second ion-depleting compartment while the first fluid stream flows through said at least one second ion-concentrating compartment in the second direction.