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.

A bipolar membrane electrodialysis method and system are described for purifying an organic acid from an aqueous solution containing the salt of the organic acid. The system includes a bipolar membrane electrodialysis stack that includes at least one three-compartment bipolar membrane electrodialysis cell and at least one two-compartment bipolar membrane electrodialysis cell. The method includes recirculating the solution of organic acid produced from the three-compartment bipolar membrane electrodialysis cell and two-compartment bipolar membrane electrodialysis cell. Cation or anion exchange resins may be included in the spacers of acid compartment to increase the conductivity of acid compartments, thereby increasing current density of the bipolar electrodialysis stack and decreasing power consumption.

A bipolar electrodialysis (BPED) cell is able to bipolar convert salt solutions into acid and base solutions. However, protons migrate through the anion exchange membranes and tend to neutralize the base solution. In a bipolar electrodialysis system described herein, multiple BPED cells are arranged to provide a multi-stage treatment system. Up to half, or up to one third, of the stages have cells with acid block anion membranes. The one or more stages with acid block anion membranes are located at the acid product output end of the system, where the acid concentration in the system is the highest. Replacing the traditional anion membranes in some of the stages with acid block anion membranes allows higher concentration products to be produced with moderate increase in energy consumption.

The present disclosure provides devices and methods of using same for cleansing a solution (e.g., a salt or used dialysis solution) of urea via electrooxidation, and more specifically to cleansing a renal therapy solution/dialysis solution of urea via electrooxidation so that the renal therapy solution/dialysis solution can be used or reused for treatment of a patient. In an embodiment, a device for the removal of urea from a fluid having urea to produce a cleansed fluid includes a urea decomposition unit and an electrodialysis unit.

Systems and methods of making lactobionic acid are described. The systems include two-compartment cation bipolar electrodialysis assemblies having at least one cell that includes a cation ion-exchange membrane and a bipolar membrane. The membranes define the borders of a pair of flow channels for a separate (i) caustic stream and (i) purified lactobionic acid stream. Lactobionate ions in the lactobionic acid stream do not cross a membrane in the electrodialysis assembly, which reduces membrane fouling. The methods include passing a lactobionate salt through a two-compartment cation bipolar electrodialysis assembly. The electrodialysis assembly includes at least one two-compartment cation bipolar membrane cell, and separates the lactobionate salt into a caustic compound and the lactobionic acid. The assembly is designed so the lactobionate ions do not cross an ion exchange membrane in the assembly to form the lactobionic acid, which reduces membrane fouling.

Drainage water that includes anions and cations dissolved in water and that is received from an agricultural or industrial facility is treated by applying a voltage to an anode and a cathode on opposite sides of an electrically driven separation apparatus that further includes at least one monovalent-selective ion exchange membrane between the anode and the cathode. The drainage water is passed through the electrically driven separation apparatus, wherein monovalent ions are selected from the drainage water through the monovalent-selective ion exchange membrane. The drainage water is then recirculated as treated water through the facility after the monovalent ions are removed.

The present invention relates to a method for producing lithium hydroxide and lithium carbonate, wherein the lithium hydroxide and the lithium carbonate can be produced by a series of steps of: performing bipolar electrodialysis of a lithium-containing solution from which divalent ion impurities have been removed; concentrating lithium in the lithium-containing solution and at the same time, converting the lithium to lithium hydroxide; and carbonating the lithium hydroxide to obtain lithium carbonate.

The disclosure relates to methods for preparing lithium hydroxide. For example, such methods can comprise mixing a lithium-containing material with an acidic aqueous composition optionally comprising lithium sulfate and thereby obtaining a mixture; roasting the mixture under suitable conditions to obtain a roasted, lithium-containing material; leaching the roasted material under conditions suitable to obtain a first aqueous composition comprising lithium sulfate; submitting the first aqueous composition comprising lithium sulfate to an electromembrane process under suitable conditions for at least partial conversion of the lithium sulfate into lithium hydroxide and to obtain a second aqueous composition comprising lithium sulfate, the electromembrane process involving a hydrogen depolarized anode; optionally increasing concentration of acid in the second aqueous composition; and using the second aqueous composition comprising lithium sulfate as the acidic aqueous composition optionally comprising lithium sulfate for mixing with the lithium-containing material and to obtain the mixture.

Wastewater containing scale components, organic substances, inorganic ions, and the like, such as human effluent, generated in a closed system space, such as a nuclear shelter, a hazardous shelter, a space station or a moon-Mars mission manned spacecraft, or a lunar base is efficiently treated by a simple structural apparatus, so that water is recovered. After a hardness component is removed from water to be treated, such as human effluent, by a softening device, and heat exchange is performed between softening treated water and electrolysis treated water by a heat exchanger, by a high-temperature and high-pressure electrolysis device, organic substances, urea, ammonia, and the like are removed by electrolysis performed under high-temperature and high-pressure conditions. After the electrolysis treated water is processed by a deaeration treatment using a deaeration membrane device, a desalting treatment is performed by acid/alkali manufacturing electrodialysis devices and provided in series at two stages.

Disclosed is a process for enriching silicate content in drinking water that includes separating raw water via reverse osmosis into a permeate comprising demineralised raw water and a retentate comprising mineral enriched raw water. The permeate is mixed with a water glass solution comprising sodium silicate and/or potassium silicate. An ion exchange process is used to reduce the concentration of sodium and/or potassium ions in at least part of the mixture. At least part of the retentate is supplied to the mixture after reducing the concentration of sodium and/or potassium ions to provide a silicate-enriched drinking water. Also disclosed is an apparatus for producing a drinking water enriched with silicate. The apparatus includes a reverse osmosis unit, a mixing unit, an ion exchanger, and a feed unit for feeding at least part of the retentate to the mixture after reducing the concentration of sodium and/or potassium ions.