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.

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.

The present invention relates to a hydrogen gas production method, which includes: a first step of concentrating an aqueous solution containing an alkali metal formate; a second step of protonating at least a part of the alkali metal formate by electrodialysis to produce a formic acid; and a third step of decomposing the formic acid to produce a hydrogen gas.

A suppressor device for an ion chromatograph is provided between a separation column and a detector of an ion chromatograph. An electrodialysis suppressor includes a first flow path to which an eluent flowing from the separation column is supplied, a second flow path to which a regeneration liquid is supplied, an ion exchange membrane provided between the first flow path and the second flow path and an electrode to which a voltage is applied. A power supply circuit that applies a voltage to the electrode is turned off in a case in which an eluent is not supplied to the first flow path of the electrodialysis suppressor.

A suppressor device for an ion chromatograph is provided between a separation column and a detector of an ion chromatograph. An electrodialysis suppressor includes a first flow path to which an eluent flowing from the separation column is supplied, a second flow path to which a regeneration liquid is supplied, an ion exchange membrane provided between the first flow path and the second flow path and an electrode to which a voltage is applied. A power supply circuit that applies a voltage to the electrode is turned off in a case in which an eluent is not supplied to the first flow path of the electrodialysis suppressor.

Electrodeionization and electrodialysis systems which eliminate or substantially prevent the feed water from entering the concentrating compartments, for improving the recovery of product water as well as improving the current efficiency. Electro-osmotically generated flows of water entering from the diluting compartments of the stack constitutes the majority of concentrate feed, leading to the production of high purity, desalinated waters in the diluting compartments and highly concentrate solutions in the concentrate compartments.

Disclosed herein a monovalent-ion-selective composite membrane comprising a polymeric cation exchange membrane and a metal-oxide-based layer, wherein said metal-oxide-based layer comprises a metal oxide or an organic-inorganic hybrid polymer, of e.g. Zn, Al, Mg, Si, Cu, W, Ni, or Ti. Also disclosed are the methods for the preparation of the membrane, and also electrodialysis assemblies comprising the membranes.

Disclosed herein a monovalent-ion-selective composite membrane comprising a polymeric cation exchange membrane and a metal-oxide-based layer, wherein said metal-oxide-based layer comprises a metal oxide or an organic-inorganic hybrid polymer, of e.g. Zn, Al, Mg, Si, Cu, W, Ni, or Ti. Also disclosed are the methods for the preparation of the membrane, and also electrodialysis assemblies comprising the membranes.

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.