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.

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.

The methods and systems disclosed here relate to treating water. In certain embodiments, a treatment system comprises an electrochemical water treatment device, a recirculating concentrate stream in fluid communication with the electrochemical water treatment device, a flow control device in fluid communication with a first flow path comprising acidic water and configured to be in fluid communication with the recirculating concentrate stream, and a second flow path comprising feed water and configured to be in fluid communication with the recirculating concentrate stream, and a control system in communication with the flow control device. The treatment system may further comprise a recirculating dilution stream in fluid communication with a second inlet and a second outlet of the electrochemical water treatment device.

The methods and systems disclosed here relate to treating water. In certain embodiments, a treatment system comprises an electrochemical water treatment device, a recirculating concentrate stream in fluid communication with the electrochemical water treatment device, a flow control device in fluid communication with a first flow path comprising acidic water and configured to be in fluid communication with the recirculating concentrate stream, and a second flow path comprising feed water and configured to be in fluid communication with the recirculating concentrate stream, and a control system in communication with the flow control device. The treatment system may further comprise a recirculating dilution stream in fluid communication with a second inlet and a second outlet of the electrochemical water treatment device.

A two-stage electrodialysis system and a method for recovering waste CO.sub.2-lean amine solvent are provided. The system includes an amine solution pretreatment filtering system, a C-A homogeneous membrane electrodialysis device, a BP-A bipolar membrane electrodialysis system, and a CO.sub.2 recovery and capture system. The C-A homogeneous membrane electrodialysis system includes a material chamber, a C-A homogeneous membrane electrodialysis device, a concentrated HSSs waste solution chamber, an electrode solution chamber, and corresponding pipelines and peristaltic pumps. The BP-A bipolar membrane electrodialysis system includes a secondary feed chamber, a BP-A bipolar membrane electrodialysis device, an acid liquor chamber, an electrode solution chamber, and corresponding pipelines and peristaltic pumps. The waste CO.sub.2-lean amine solvent enters the material chamber after passing through the amine solution pretreatment filtering system. The concentrated HSSs waste solution chamber is connected to the secondary feed chamber by a buffer tank.

Provided are electrodialysis systems for removing ions from heavy ends. The electrodialysis systems include an electrodialysis device comprising a brine inlet stream, a heavy ends inlet stream, a brine outlet stream, and a product outlet stream, wherein the brine outlet stream comprises more acetic acid than the brine inlet stream, and the product outlet stream comprises no more than 10% the amount of ions relative to an amount of ions in the heavy ends inlet stream.

A conductive nanoporous membrane system has a first ion exchange membrane formed from a nanoporous substrate that is coated with a metal or carbon or conductive polymers to form a conductive membrane, a second ion exchange membrane that is also formed from a nanoporous substrate coated with a metal to form a conductive membrane is positioned in spaced relation to the first conductive membrane and coupled to a voltage source; the negatively potential membrane acts as a cation exchange membrane in the presence of an electrolyte, and the positively connected electrode behave as anodic exchange membrane in the presence of an electrolyte due to the formation of electrical double layers at the interface between metal and liquid electrolyte.

A photodialysis device that can desalinate saline streams is described herein. The device can have a desalination rate that is significantly faster than current solar thermal desalination technology. Salt is removed from water by passing ionic current derived from sunlight through this water using dye-sensitized membranes. The device can serve as a distributed, low-cost technology that can efficiently and effectively desalinate low salinity sources of water, which is particularly useful for agriculture and drinking water applications.

A photodialysis device that can desalinate saline streams is described herein. The device can have a desalination rate that is significantly faster than current solar thermal desalination technology. Salt is removed from water by passing ionic current derived from sunlight through this water using dye-sensitized membranes. The device can serve as a distributed, low-cost technology that can efficiently and effectively desalinate low salinity sources of water, which is particularly useful for agriculture and drinking water applications.