Provided are electrodialysis systems for removing silica from a desalinated water stream and methods for removing silica from a desalinated water stream. For example, described are bipolar membrane electrodialysis devices for removing silica from water comprising one or more anion exchange membranes; one or more bipolar membranes; and a pair of electrodes comprising a positive electrode and a negative electrode. Also described are electrodialysis systems comprising: one or more electrodialysis devices for the removal of dissolved ions and one or more bipolar membrane electrodialysis devices, wherein a product inlet stream of the one or more bipolar membrane electrodialysis devices comprises the product outlet stream of the one or more electrodialysis devices.

Provided are electrodialysis systems for removing silica from a desalinated water stream and methods for removing silica from a desalinated water stream. For example, described are bipolar membrane electrodialysis devices for removing silica from water comprising one or more anion exchange membranes; one or more bipolar membranes; and a pair of electrodes comprising a positive electrode and a negative electrode. Also described are electrodialysis systems comprising: one or more electrodialysis devices for the removal of dissolved ions and one or more bipolar membrane electrodialysis devices, wherein a product inlet stream of the one or more bipolar membrane electrodialysis devices comprises the product outlet stream of the one or more electrodialysis devices.

A system for producing magnesium chloride includes a removal unit, and a concentration unit that is connected to the removal unit. The removal unit generates feedstock water by removing sulfate ions and sodium ions from treatment target water having seawater as a feedstock. The concentration unit generates a slurry in which magnesium chloride is crystallized by concentrating the feedstock water. The removal unit has a first removal unit which reduces the sulfate ion concentration compared to the sulfate ion concentration in the treatment target water, and a second removal unit which reduces the sodium ion concentration compared to the sodium ion concentration in the treatment target water.

The present invention is in the field of a system for gas recovery from wastewater, a method for treating wastewater, and a method wherein ammonia and carbon dioxide are recovered. Typically a wastewater stream is fed into the system, treated and stripped from ammonia and carbon dioxide, and a cleaner stream is released.

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.

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.

The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.

The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.

The present invention relates to an ion-selective composite membrane having a thickness of between 4 μm and 100 μm, comprising at least one inner layer disposed between two outer layers, wherein: —the outer layers are each formed of a first material comprising a network of nanofibres and/or crosslinked microfibres and pores with a diameter of between 10 nm and 10 μm, —the inner layer is formed of a second material comprising nanoparticles functionalized at the surface by charged groups and/or groups which become charged in the presence of water and having pores with a diameter of between 1 and 100 nm.

The present invention relates to an ion-selective composite membrane having a thickness of between 4 μm and 100 μm, comprising at least one inner layer disposed between two outer layers, wherein: —the outer layers are each formed of a first material comprising a network of nanofibres and/or crosslinked microfibres and pores with a diameter of between 10 nm and 10 μm, —the inner layer is formed of a second material comprising nanoparticles functionalized at the surface by charged groups and/or groups which become charged in the presence of water and having pores with a diameter of between 1 and 100 nm.