There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

There are provided processes for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum, the process comprising: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum with lithium hydroxide, sodium hydroxide and/or potassium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate to an electromembrane process for converting the lithium sulfate, sodium sulfate and/or potassium sulfate into lithium hydroxide, sodium hydroxide and/or potassium hydroxide respectively; reusing the sodium hydroxide obtained by the electromembrane process for reacting with the metal sulfate; and reusing the lithium hydroxide obtained by the electromembrane process for reacting with the metal sulfate and/or with the metal hydroxide.

A device and process for the separate removal of oppositely charged ions from electrolyte solutions and recombining them to form new chemical compositions. The invention provides the ability to create multiple ion flow channels and then form new chemical compositions therefrom. The process is accomplished by selectively combining oppositely charged ions of choice from different electrolyte solutions via the capacitive behavior of high electrical capacitance electrodes confined in insulated containers. Industrial plants employing the inventive process can have the flexibility to produce needed industrial chemical compounds such as Soda Ash, Caustic Soda, hydrochloric acid and chlorine gas, based on market demand, and can be located near points of consumption to significantly reduce transportation costs.

A device and process for the separate removal of oppositely charged ions from electrolyte solutions and recombining them to form new chemical compositions. The invention provides the ability to create multiple ion flow channels and then form new chemical compositions therefrom. The process is accomplished by selectively combining oppositely charged ions of choice from different electrolyte solutions via the capacitive behavior of high electrical capacitance electrodes confined in insulated containers. Industrial plants employing the inventive process can have the flexibility to produce needed industrial chemical compounds such as Soda Ash, Caustic Soda, hydrochloric acid and chlorine gas, based on market demand, and can be located near points of consumption to significantly reduce transportation costs.

Methods of producing an ion exchange membrane support are disclosed. The methods include saturating a polymeric microporous substrate with a charged monomer solution comprising at least one functional monomer, a cross-linking agent, and an effective amount of at least one photopolymerization initiator and polymerizing the at least one functional monomer by exposing the saturated polymeric microporous substrate to ultraviolet light under conditions effective to cross-link the at least one functional monomer and produce the ion exchange membrane support. Methods of producing a monovalent selective ion exchange membrane are also disclosed. The methods include functionalizing an exterior surface of the ion exchange membrane support with a charged compound layer, drying the ion exchange membrane support and soaking the ion exchange membrane support in a solution comprising an acid or a base for an amount of time effective to produce the monovalent selective ion exchange membrane.

In an acidic treatment liquid processing apparatus, a space between a first electrode and a second electrode spaced from each other is separated by a first diaphragm permeable and a second diaphragm into a first chamber, a second chamber, and a third chamber. While the first chamber is fed with an acidic treatment liquid containing a dichromate ion and a metal cation, the second chamber is fed with a first acid aqueous solution, and the third chamber is fed with a second acid aqueous solution, a voltage is applied using the first electrode as an anode and the second electrode as a cathode.

An electrodialysis device and method for selective removal of drinking water target ions were provided. It belongs to the technical field of drinking water safety. A method of electrodialysis with slightly brackish water is proposed. By means of ion electromigration control, the resistance is converted from the single membrane resistance to the diffusion boundary layer resistance; and the diffusion boundary layer is fully compressed by controlling the electrodialysis membrane, the electrodialysis membrane stack, and the electrodialysis process parameters. So that the relative electromigration rate of the target ions is improved. According to the method, the initial concentration effect, the competition effect, the synergistic effect, the concentration diffusion, the differential pressure permeation, and other influences of electrodialysis are integrated for selectively removing the target ions. It significantly reduces the cost of water treatment and improves the long-term stability and operational applicability of the device.

An electrodialysis device and method for selective removal of drinking water target ions were provided. It belongs to the technical field of drinking water safety. A method of electrodialysis with slightly brackish water is proposed. By means of ion electromigration control, the resistance is converted from the single membrane resistance to the diffusion boundary layer resistance; and the diffusion boundary layer is fully compressed by controlling the electrodialysis membrane, the electrodialysis membrane stack, and the electrodialysis process parameters. So that the relative electromigration rate of the target ions is improved. According to the method, the initial concentration effect, the competition effect, the synergistic effect, the concentration diffusion, the differential pressure permeation, and other influences of electrodialysis are integrated for selectively removing the target ions. It significantly reduces the cost of water treatment and improves the long-term stability and operational applicability of the device.

A composite membrane comprising: a) a first layer comprising a first porous support and a first ionic polymer present in the pores of the first porous support; b) a second layer comprising a second porous support and a second ionic polymer present in the pores of the second porous support; c) a third layer comprising a third porous support, a third ionic polymer and a fourth ionic polymer, wherein the third ionic polymer is present in the pores of the third porous support; wherein: (i) one of the first ionic polymer and the second ionic polymer is a cationic polymer and the other is an anionic polymer; (ii) the third layer c) is interposed between the first layer a) and the second layer b); (iii) the third ionic polymer comprises a network of pores and the fourth ionic polymer is present within the pores of the third ionic polymer; and (iv) one of the third ionic polymer and the fourth ionic polymer is a cationic polymer and the other is an anionic polymer.