A hybrid electro-pressure driven method for the recovery, purification, and concentration of lithium salts is described. A fractionating electrodialysis stack equipped with selective ion exchange membranes is s used to separate a lithium containing brine into a monovalent enriched fraction and a divalent enriched fraction. The monovalent enriched fraction is further processed to remove remaining impurities by use of pressure driven nanofiltration. An optional concentrating electrodialysis device may further concentrate the monovalent enriched fraction in lithium content. The method may be combined with a subsequent solvent extraction and electrolysis step to produce lithium hydroxide, a Li+ selective sorbent step for producing purified lithium chloride, or a Li+ selective sorbent and precipitative step to produce lithium carbonate.

Techniques according to the present disclosure include capturing carbon dioxide from a dilute gas source with a CO.sub.2 capture solution to form a carbonate-rich capture solution; separating at least a portion of carbonate from the carbonate-rich capture solution; forming an electrodialysis (ED) feed solution; flowing a water stream and the ED feed solution to a bipolar membrane electrodialysis (BPMED) unit; applying an electric potential to the BPMED unit to form at least two ED product streams including a first ED product stream including a hydroxide; and flowing the first ED product stream to use in the capturing the carbon dioxide from the dilute gas source with the CO.sub.2 capture solution.

Techniques according to the present disclosure include capturing carbon dioxide from a dilute gas source with a CO.sub.2 capture solution to form a carbonate-rich capture solution; separating at least a portion of carbonate from the carbonate-rich capture solution; forming an electrodialysis (ED) feed solution; flowing a water stream and the ED feed solution to a bipolar membrane electrodialysis (BPMED) unit; applying an electric potential to the BPMED unit to form at least two ED product streams including a first ED product stream including a hydroxide; and flowing the first ED product stream to use in the capturing the carbon dioxide from the dilute gas source with the CO.sub.2 capture solution.

Compositions, systems, and methods for selectively leaching and/or extracting lithium from sedimentary deposits and other resources are generally described.

A method for desalination is provided. An electric potential difference is applied across a saline solution, where a salinity of the saline solution is in a range of 2.5 to 7.8 parts per thousand. The saline solution is separated, using electrodialysis, into a concentrated saline solution and a first diluate. The concentrated saline solution is transferred to a reverse osmosis chamber. The concentrated saline solution is pumped through a partially permeable membrane, thereby removing salt ions from the concentrated saline solution, and creating a second diluate and a brine solution. A pressure of the solution is then increased, using a pressure exchanger, by transferring water pressure from the brine solution to the concentrated saline solution. The first diluate and the second diluate are combined, where a first recovery ratio of the first diluate is greater than a second recovery ratio of the second diluate.

A wastewater treatment equipment and a treatment method of a wastewater are provided. The wastewater treatment equipment includes: a microfiltration unit, configured to receive and filter a wastewater to obtain a solution; a membrane salt separation unit, configured to receive the solution and separate monovalent ions and multivalent ions from the solution to obtain a first solution including the monovalent ions and a second solution including the multivalent ions; a first evaporative crystallization unit, configured to crystallize the first solution to form a monovalent salt; and a second evaporative crystallization unit, configured to crystallize the second solution to form a mixed salt; the microfiltration unit is connected to the membrane salt separation unit, and the first evaporative crystallization unit and the second evaporative crystallization unit are both directly connected to the membrane salt separation unit, the wastewater treatment equipment can achieve the standard discharge of wastewater.

A system and method for producing minerals from divalent ion-containing brine stream includes rejecting sulfate from a divalent-ion rich reject stream in a first nanofiltration seawater reverse osmosis (NF-SWRO) unit, producing solid calcium sulfate dihydrate and a magnesium-rich brine stream in a first concentration unit, concentrating the magnesium-rich brine stream to a saturation point of sodium chloride in a second concentration unit, producing solid sodium chloride and a supernatant product stream in a first crystallizing unit, produce a concentrated magnesium-rich bittern stream from the supernatant product stream in a third concentration unit, and at least one of producing hydrated magnesium chloride from the concentrated magnesium-rich bittern stream in a second crystallizing unit and producing anhydrous magnesium chloride by prilling the concentrated magnesium-rich bitterns stream under a hydrogen chloride atmosphere in a dry air process unit.

Disclosed is a method for resolving an optical isomer from a racemate by means of electrodialysis. Specifically, an electrodialysis technique is used in an enzymatic resolution process, mainly in the separation of products after enzymatic resolution. Taking a preparation process for D-pantolactone as an example, the key point is that D-pantoic acid and L-pantolactone are separated from an enzymatic resolution solution by means of an electrodialysis method, which replaces the existing organic solvent extraction method. The process method is simple and easy to operate, has a high yield of D-pantoic acid of a good purity, greatly reduces the usage amount of an organic solvent, reduces production costs and is environmentally friendly, such that the working environment of workers can be improved to a great extent, and the operation safety index is improved.

A method is disclosed for concentrating and purifying an eluate brine and producing a purified lithium compound. An extraction eluate, rich in lithium, is directed to a nanofiltration unit or a softening process that removes sulfate and/or calcium and magnesium. Permeate from the nanofiltration unit or the effluent from the softening process is directed through an electrodialysis unit. As the lithium-rich solution moves through the electrodialysis unit, lithium, sodium and chloride ions pass from the solution through a cation-transfer membrane and an anion-transfer membrane to concentrate compartments. A dilute stream is directed through the concentrate compartments and collects the lithium, sodium and chloride ions. The electrodialysis unit also produces a product stream which contains non-ionized impurities, such as silica and/or boron. Concentrate from the electrodialysis unit is subject to a precipitation process that produces a lithium compound that is subsequently subjected to a purification process.

A wastewater treatment method includes: a soft water treatment 1 of crystallizing calcium carbonate from wastewater to remove the calcium carbonate therefrom; and an electrolysis 2 of electrolyzing some of the wastewater from which the calcium carbonate has been removed to obtain an acidic aqueous solution and an alkaline aqueous solution, wherein at least some of the alkaline aqueous solution is circulated to be used in the soft water treatment 1.