The systems and methods disclosed herein process produced/flowback water, such as high total dissolved solids produced water, to generate high purity, high value products with little to no waste. The generated high purity, high value products include caustic soda, hydrochloric acid, and/or sodium hypochlorite. Further, the methods and systems disclosed herein generate high quality brine for electrolysis through the systematic removal of contaminants such as but not limited to suspended solids, iron, sulfides, barium, radium, strontium, calcium, magnesium, manganese, fluoride, heavy metals, organic carbon, recoverable hydrocarbons, silica, lithium, and/or nitrogen containing compounds. Further, some products generated by the systems and methods disclosed herein may be recovered and reutilized or sold for other uses, such as carbon dioxide, calcium oxide, chlorine, magnesium oxide, calcium carbonate, and/or barium sulfate.

The systems and methods disclosed herein process produced/flowback water, such as high total dissolved solids produced water, to generate high purity, high value products with little to no waste. The generated high purity, high value products include caustic soda, hydrochloric acid, and/or sodium hypochlorite. Further, the methods and systems disclosed herein generate high quality brine for electrolysis through the systematic removal of contaminants such as but not limited to suspended solids, iron, sulfides, barium, radium, strontium, calcium, magnesium, manganese, fluoride, heavy metals, organic carbon, recoverable hydrocarbons, silica, lithium, and/or nitrogen containing compounds. Further, some products generated by the systems and methods disclosed herein may be recovered and reutilized or sold for other uses, such as carbon dioxide, calcium oxide, chlorine, magnesium oxide, calcium carbonate, and/or barium sulfate.

Methods and systems for electrolyte regeneration are provided, which regenerate a spent alkaline electrolyte (SE) comprising dissolved aluminum hydrates from an aluminum-air battery, by electrolysis, to precipitate aluminum tri-hydroxide (ATH) and form regenerated alkaline electrolyte, and adding a same-cation salt to an anolyte used in the electrolysis to supplant a corresponding electrolyte cation. The regeneration may be carried out continuously and further comprise mixing the SE and the same-cation salt in a salt tank configured to deliver the anolyte, removing the regenerated alkaline electrolyte from a catholyte tank configured to deliver the catholyte, and filtering the ATH from a solution delivered from the salt tank to the anolyte. Optionally, the salt may be a buffering salt, and in some cases chemical reactions may be used to enhance the regeneration by electrolysis.

Methods and systems for electrolyte regeneration are provided, which regenerate a spent alkaline electrolyte (SE) comprising dissolved aluminum hydrates from an aluminum-air battery, by electrolysis, to precipitate aluminum tri-hydroxide (ATH) and form regenerated alkaline electrolyte, and adding a same-cation salt to an anolyte used in the electrolysis to supplant a corresponding electrolyte cation. The regeneration may be carried out continuously and further comprise mixing the SE and the same-cation salt in a salt tank configured to deliver the anolyte, removing the regenerated alkaline electrolyte from a catholyte tank configured to deliver the catholyte, and filtering the ATH from a solution delivered from the salt tank to the anolyte. Optionally, the salt may be a buffering salt, and in some cases chemical reactions may be used to enhance the regeneration by electrolysis.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

Disclosed herein is a method of recovering lithium or sodium from an active material of a lithium or sodium ion battery. In a preferred embodiment, the method comprises a redox-targeting reaction of a used active material LiFeP04 with a redox mediator [Fe(CN).sub.6].sup.3− in a tank to produce lithium ions, circulating the reacted redox solution into a cell to regenerate said redox mediator and enabling said lithium ions to migrate through a membrane towards a cathode wherein said lithium ions are captured as LiOH through an electrochemical reaction.

Disclosed herein is a method of recovering lithium or sodium from an active material of a lithium or sodium ion battery. In a preferred embodiment, the method comprises a redox-targeting reaction of a used active material LiFeP04 with a redox mediator [Fe(CN).sub.6].sup.3− in a tank to produce lithium ions, circulating the reacted redox solution into a cell to regenerate said redox mediator and enabling said lithium ions to migrate through a membrane towards a cathode wherein said lithium ions are captured as LiOH through an electrochemical reaction.

The present invention refers to the field of flue gas purification, which discloses a method and apparatus for capturing carbon dioxide and producing sulfuric acid by sodium bisulfate; using a three-format electrodialysis apparatus to convert the desulfurized by-product NaHSO.sub.4 into H.sub.2SO.sub.4 while capturing CO.sub.2 in the flue gas in the cathode chamber. Under the action of electric field drive and ion exchange membrane, HSO.sub.4.sup.− enters the anode chamber to generate H.sub.2SO.sub.4 and is concentrated, and Na.sup.+ enters the cathode chamber to generate NaOH; the flue gas containing CO.sub.2 to be treated is introduced from the cathode chamber and absorbed by NaOH. The invention provides a simple, green, and economic proceeding method to capture the carbon dioxide in the flue gas during the comprehensive utilization of sodium bisulfate solution, which is of better environmental benefits and improvement of the flue gas treatment technology and reducing the pressure of desulfurization gypsum treatment.

Systems and methods are described for producing lithium hydroxide from lithium chloride and sodium chloride through an electrolysis process. A solution of lithium hydroxide and sodium hydroxide may be produced through electrolysis of a lithium chloride and sodium chloride solution. Lithium hydroxide in the produced solution may then be crystallized and filtered out to produce substantially pure lithium hydroxide crystals.