Methods, systems, and techniques for desalinating monovalent anion species from wastewater. A system includes an electrodialysis stack that performs the desalination. The stack has a cathode, an anode, and at least one electrodialysis cell. The at least one electrodialysis cell includes a product chamber, a metal cation concentrating chamber adjacent to a cathodic side of the product chamber, and a transfer solution chamber adjacent to an anodic side of the product chamber. The product chamber and the metal cation concentrating chamber are each bounded by and share a cation exchange membrane, the product chamber and the transfer solution chamber are each bounded by and share a monovalent anion exchange membrane, and the transfer solution chamber is bounded on an anodic side by one of an anion exchange membrane and a monovalent anion exchange membrane. The wastewater may be generated by a flue gas desulfurization process.

A method of cleaning used dialysis fluid having urea to produce a cleaned dialysis fluid, the method including passing the used dialysis fluid having urea through a combination electrodialysis and urea oxidation cell, the cell including (i) a first set of electrodes for separation of the used dialysis fluid having urea into an acid stream and a basic stream, wherein the first set of electrodes includes an anode and a cathode; (ii) one or more second set of electrodes positioned to contact the basic stream with an electrocatalytic surface for decomposition of urea via electrooxidation, wherein the one or more second set of electrodes includes an anode and a cathode; and (iii) at least one power source to provide the first and second sets of electrodes with an electrical charge to activate the electrocatalytic surface.

Processes, systems, and techniques for treating produced water drawn from a subterranean formation. The produced water is provided and contains dissolved solids and magnesium, calcium, and sodium ions. The produced water is desalinated using an electrically-driven membrane separation apparatus that includes alternating anion exchange membranes and cation exchange membranes defining opposing sides of alternating product and concentrate chambers. The desalinating involves flowing the produced water through the product chamber, flowing a second water through the concentrate chamber, and applying an electric potential across the cation and anion exchange membranes as the produced and second waters flow through the product and concentrate chambers, respectively. The product water is consequently produced and has a total dissolved solids content of between 300 mg/L and 8,000 mg/L, a total concentration of calcium ions and magnesium ions less than 100 mg/L, and a sodium adsorption ratio of 20 to 90.

A device and method are described for the treatment of blood, which device may be used in conjunction with or in place of a failed Kidney. The device includes an ultrafiltration unit to remove proteins, red and white blood cells and other high molecular weight components, a nanofiltration unit to remove glucose, at least one electrodeionization unit to transport ions from the blood stream, and a reverse osmosis unit to modulate the flow of water, to both the blood and urine streams. In one embodiment, a specialized electrodeionization unit is provided having multiple chambers defining multiple dilute fluid channels, each channel filled with an ion specific resin wafer, and electrodes at the extremity of the device and proximate each of the resin filled dilute channels. By selective application of voltages to these electrodes, the ion transport functionality of a given dilute channel can be turned on or off.

A method of cleaning used dialysis fluid having urea to produce a cleaned dialysis fluid, the method including passing the used dialysis fluid having urea through a combination electrodialysis and urea oxidation cell, the cell including (i) a first set of electrodes for separation of the used dialysis fluid having urea into an acid stream and a basic stream, wherein the first set of electrodes includes an anode and a cathode; (ii) one or more second set of electrodes positioned to contact the basic stream with an electrocatalytic surface for decomposition of urea via electrooxidation, wherein the one or more second set of electrodes includes an anode and a cathode; and (iii) at least one power source to provide the first and second sets of electrodes with an electrical charge to activate the electrocatalytic surface.

A membrane stack comprising the following components: (a) a first ion diluting compartment (D1); (b) a second ion diluting compartment (D2); (c) a first ion concentrating compartment (C1); (d) a second ion concentrating compartment (C2); and (e) a membrane wall (CEM1, mAEM, mCEM, AEM, CEM2) between each compartment and on the outside of the first and last compartment of the stack; wherein: (i) each membrane wall comprises a cation exchange membrane (CEM1, mCEM, CEM2) or an anion exchange membrane (mAEM, AEM) and the order of the cation and anion exchange membranes alternates from each wall to the next; (ii) the membrane walls (mAEM, mCEM) on each side of compartment (a) both have a higher monovalent ion selectivity than the corresponding membrane walls (AEM, CEM2) on each side of compartment (b); and (iii) the stack further comprises a means for communicating fluid between compartments (a) and (b).

A resin-wafer electrodeionization (RW-EDI) apparatus for purifying water for coffee brewing comprises a cathode; an anode; and multiple porous solid resin wafer exchange units arranged in a stack between the cathode and the anode, and an air distributor adapted and arranged to aerate the water to be purified. Each unit comprises a monovalent cation exchange membrane (CEM), an anion exchange membrane (AEM), and an ion exchange resin wafer between the CEM and the AEM, which is in contact with, and in fluid flow connection with the CEM and AEM. Each resin wafer comprises a cation exchange resin and an anion exchange resin. The units are oriented with the CEM facing the cathode and the AEM facing the anode, with space between the units defining ion concentrate chambers. Bipolar ion exchange membranes separate the anode and cathode from their nearest resin wafer exchange units.

The present invention relates to a bipolar ion exchange membrane and a production method therefor, and provides a bipolar ion exchange membrane comprising a first polar heterogeneous ion exchange membrane and a second polar homogeneous ion exchange membrane stacked on each other, wherein the first polar heterogeneous ion exchange membrane is formed of an ion exchange resin powder and a binder resin that contain a first polar ion exchange group, the second polar homogeneous ion exchange membrane is formed of a matrix resin containing a second polar ion exchange group, and an interface between the first polar heterogeneous ion exchange membrane and the second polar homogeneous ion exchange membrane is a heterogeneous interface.

Electrodeionization apparatuses, systems including a reactor system and an electrodeionization system, and methods of purifying acetic acid are provided herein. In some embodiments, the electrodeionization apparatus includes an anode, and three spaced apart membranes located between the anode and the cathode: a first cation exchange membrane, a first anion exchange membrane, a second cation exchange membrane, defining: a first electrode rinse passage between the anode and the first cation exchange membrane, a first concentrate passage between the first cation exchange membrane and the first anion exchange membrane, a feed stream passage located between the first anion exchange membrane and the second cation exchange membrane, and a second electrode rinse passage between the second cation exchange membrane and the cathode. In some embodiments, the electrodeionization apparatus also includes at least one propionate-selective ion exchange resin wafer within the feed stream passage.

Various examples are provided related to dialysate-free renal replacement. In one example, a dialysate-free continuous renal replacement system includes a blood filtration stage (e.g., in a microfluidic membrane module). The blood filtration stage can include a blood filtration membrane configured to that can provide a filtered fluid by renal filtration of blood passing through the blood filtration stage at arterial pressure. The continuous renal replacement system can also include a salt recovery stage and a water recovery stage. The salt recovery stage can recover ions through separation from the blood filtration stage. The water recovery stage can separate water from the desalted fluid from the salt recovery stage, where the water is combined with the separated ions and reinfused into the blood after passing through the blood filtration stage.