The invention relates to a method for producing a tubular electrochemical separation unit comprising a plurality of electrochemical cells, arranged electrically in series, and comprising at least three layers, said method comprising: —a deposition step (110) of a first layer to form a first discontinuous layer (10) comprising several successive tubular modules (11) separated by spaces (12), —a deposition step (120) of a second layer, said deposition being achieved to form a second discontinuous layer (20) comprising several successive tubular modules (21) separated by spaces (22), so that tubular modules (11) are partially coated with tubular modules (21) of the second layer (20), —a deposition step (130) of a third layer, said deposition being achieved to form a third discontinuous layer (30) comprising several successive tubular modules (31) separated by spaces (32), so that tubular modules (21) are partially coated with tubular modules of the third discontinuous layer.

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.

A dryer system includes an electrodialytic regenerator that comprises a first channel that dilutes a first stream of liquid desiccant and a second channel that concentrates a second stream of the liquid desiccant. An air-liquid interface is in fluid communication with the second stream of the liquid desiccant and an input air stream and exposes the second stream of the liquid desiccant to the input air stream. The absorption of the water from the input air stream creates a dehumidified air stream. The system includes a heat transfer element in thermal communication with the air-liquid interface. The heat transfer element carries latent heat generated from the absorption of the water from the input air stream. The system includes a drying chamber coupled to receive the dehumidified air stream and the heat.

Disclosed are electrochemical systems that include an electrodialyzer and a vapor-fed CO.sub.2 reduction (CO.sub.2R) cell to capture and convert CO.sub.2 from ocean water. The electrodialyzer includes a stack of bipolar membrane electrodialysis (BPMED) cells between end electrodes. The electrodialzyer incorporates monovalent cation exchange membranes (M-CEMs) that prevent the transfer of multivalent cations between adjacent cell compartments, allowing continuous recirculation of electrolytes and solutions, and thus providing a safer and more scaling-free electrodialysis system. In some embodiments, the electrodialyzer may be configured to replace the water-splitting reaction at end electrodes with one-electron, reversible redox couples in solution at the electrodes. As a result, in the entire electrodialyzer stack, there is no bond-making, bond-breaking reactions and there is no gas generation, which significantly simplifies the cell design and improves operational safety. The systems provide a unique technological pathway for CO.sub.2 capture and conversion from ocean water with only electrochemical processes.

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 method for extracting and purifying Dendrobium officinale polysaccharides comprises following steps: (1) fully disperse Dendrobium officinale powder in pure water to obtain crude liquid; (2) removing insoluble impurities from the crude liquid through a microfiltration membrane to obtain permeate 1 and retentate 1; (3) performing macroporous ultrafiltration treatment of the permeate 1 and collect permeate 2 and retentate 2; (4) adding an aqueous solution of edible alkali metal inorganic salt to the retentate 2, fully stirring and dissolving to obtain polysaccharide crude liquid, performing macroporous ultrafiltration treatment and collecting permeate 3 and retentate 3; (5) combining the permeate 2 and permeate 3, adding the combined permeate into an electrodialysis device for desalination, and collecting dilute solution and concentrated solution; (6) performing microporous ultrafiltration treatment of the dilute solution and collect retentate 4 and permeate 4; (7) carrying out freeze-drying of the retentate 4 to obtain Dendrobium officinale polysaccharides.

A water treatment system for brackish water is disclosed. The water treatment system includes a first electrochemical separation stage fluidly connected to a second, downstream electrochemical separation stage, with the concentrate outlet of the second electrochemical separation stage fluidly connectable to the concentration compartment of the first electrochemical separation stage and a control system configured to regulate feed directed to the concentration compartments of the first and the second electrochemical separation stages. Methods of treating brackish water to produce potable water and methods of treating brackish water using systems of the invention are disclosed. The Donnan potential difference and osmotic water losses are lessened by controlling a source and a flowrate of a make-up feed water directed to concentration compartments of first and the second electrochemical separation stages of the systems.

A carbon dioxide electrolytic device includes: a carbon dioxide electrolysis cell having a cathode and an anode flow path, a cathode, an anode, and a first diaphragm; a first current regulator to supply a first current; a first gas/liquid separator to separate a first fluid from the anode flow path into a first liquid and gas; an electrodialysis cell having, first and second electrodes, first to fourth rooms, and second to fourth diaphragms; a second current regulator to supply a second current; at least one detector out of a first detector to detect a flow rate of the first gas or a concentration of carbon dioxide in the first gas, and a second detector to detect a pH or a concentration of at least one ion in the first fluid; and a first controller to regulate a second current, in accordance with at least one detection signal.

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.

The invention relates to the field of dairy products and particularly concerns a method for the demineralization of whey. The method according to the invention comprises the following steps: obtaining a whey, electrodialysis of the whey at a temperature of 30° C. to 60° C., acidification of the whey to a pH of between 2 and 3.5, pasteurization of the acidified whey, electrodialysis of the pasteurized acidified whey at a temperature of 30° C. to 60° C., and neutralization of the demineralized whey to a pH between 6.7 and 7.2. The method according to the invention makes it possible to achieve the whey demineralization using only the method of electrodialysis while avoiding the problems conventionally encountered with this method, namely a limited demineralization rate, fouling of the membranes, and an insufficient service life.