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.

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.

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.

A method including introducing seawater into an electrodialysis unit including at least one cell including a basified solution compartment, a bipolar membrane, an acidified solution compartment and an anion exchange membrane; acidifying the seawater; removing acidified seawater from the acidified solution compartment; removing CO.sub.2 from the acidified seawater to form a decarbonized seawater; introducing the decarbonized seawater into the basified solution compartment of the electrodialysis unit. A system including an electrodialysis unit including an acidified solution compartment, a basified solution compartment, a bipolar membrane, an input to the acidified solution compartment and an input to the basified solution compartment; and a desorption unit coupled to an output of the acidified solution compartment, the desorption unit operable to remove CO.sub.2 from a solution from the acidified solution unit, the desorption unit including a solution output that is coupled to the input to the basified solution compartment.

The present disclosure provides devices and methods of using same for cleansing a solution (e.g., a salt 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.

The present disclosure provides devices and methods of using same for cleansing a solution (e.g., a salt 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 combination electrodialysis and urea oxidation cell.

Membranes for electrochemical technologies that operate at non-extreme acidic or basic conditions are described herein. The membrane can be a bipolar membrane having an anion-exchange layer, a cation-exchange layer, and a polymer layer containing a catalyst juxtaposed between the two layers. The catalyst can improve the rate for water dissociation and water formation at low applied bias thereby decreasing the overpotential and resistance for overall ion transport, especially when unequal pH values are used between the catholyte and anolyte.

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.

This invention relates to an improved electrodialysis method for preparing an amino acid from a salt of the amino acid utilizing a three-compartment bipolar membrane electrodialysis process wherein an aqueous electrolyte comprising an exogenous acid is added to the acid compartment of a three-compartment bipolar membrane apparatus. The exogenous acid is different than the amino acid and typically has a pKa less than the pKa of the amino acid.

The present invention relates to an integrated electrochemical lithium extraction process to directly produce lithium hydroxide from geothermal brine. The process integrates electrochemical silica removal, selective uptake and release of lithium using an intercalation material, and electro-driven generation of hydroxy (OH.sup.) ions.