A gradient energy system includes a membrane module including a first section, a second section, and a membrane separating the first section and the second section. A first gas may be provided within the first section. A second gas may be provided within the second section. The membrane module may be configured such that a differential associated with the first gas and the second gas generates a fluid pressure force or an electrical current. A method of recovering energy from gradients of gas mixtures may include providing a first gas to a first section of a membrane module, providing a second gas to a second section of the membrane module, which may be separated from the first section by a membrane, and/or recovering energy generated via a differential between the first gas and the second gas.

The present disclosure describes a flow-electrode capacitive deionization (FCDI) desalination system and method of use. An FCDI desalination system is described employing one or more FCDI cells equipped with two coaxially oriented membranes mounted within a column housing capped with two end caps, each end cap comprising two carbon slurry ports and one water port. The column is lined with a chargeable sleeve capable of receiving a positive or negative charge. The annular space between the chargeable sleeve and the outside surface of the outer concentric membrane creates a flow path for a first carbon slurry to pass therethrough. The space between the inside surface of the outer concentric membrane and the outer surface of the inner concentric membrane creates a flow path for the saline water to be treated. The space within the inner annular portion of the inner concentric membrane creates a flow path for a second carbon slurry and contains a chargeable rod or wire capable of receiving an opposite charge. The first and second opposed end caps on the column are outfitted to continue these independent flow paths. As the saline water travels through its flow path, its salt ions are removed through the coaxial membranes via the two carbon slurries.

An electrochemical system utilizes an anion conducting layer disposed between an anode and a cathode for transporting a working fluid. The working fluid may include carbon dioxide that is dissolved in water and is partially converted to carbonic acid that is equilibrium with bicarbonate anion. An electrical potential across the anode and cathode creates a pH gradient that drives the bicarbonate anion across the anion conducting layer to the cathode, wherein it is reformed into carbon dioxide. Therefore, carbon dioxide is pumped across the anion conducting layer.

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.

A membrane assembly for separating a feed liquid into a permeate and a retentate includes a semipermeable membrane and conductive members for applying a voltage effective for charging a semipermeable surface of the membrane, thereby reducing or preventing fouling or scaling of the membrane. The conductive members may be positioned adjacent to the semipermeable membrane, and may be configured as feed spacers or permeate spacers. Alternatively or additionally, the membrane may be electrically conductive. Power from an external source may be supplied to one or more of the conductive members, or also the membrane if conductive, which may be done wirelessly. One or more membrane assemblies may be provided in a container. One or more membrane assemblies may be provided in a stacked configuration, or wrapped around a tube in a spiral configuration.

An electrochemical system utilizes an anion conducting layer disposed between an anode and a cathode for transporting a working fluid. The working fluid may include carbon dioxide that is dissolved in water and is partially converted to carbonic acid that is equilibrium with bicarbonate anion. An electrical potential across the anode and cathode creates a pH gradient that drives the bicarbonate anion across the anion conducting layer to the cathode, wherein it is reformed into carbon dioxide. Therefore, carbon dioxide is pumped across the anion conducting layer.

An acidic treatment liquid processing apparatus includes: a tank having an interior space; a diaphragm permeable to a metal cation and separating the interior space of the tank into a first chamber and a second chamber; a first electrode disposed in the first chamber; a second electrode disposed in the second chamber; a power supply configured to apply a voltage while using the first electrode as an anode and the second electrode as a cathode; a first liquid passing part configured to pass an acidic treatment liquid containing a dichromate ion and a metal cation into the first chamber; and a second liquid passing part configured to pass an acid aqueous solution into the second chamber.

In an acidic treatment liquid processing apparatus, a space between a first electrode and a second electrode spaced from each other is separated by a first diaphragm permeable and a second diaphragm into a first chamber, a second chamber, and a third chamber. While the first chamber is fed with an acidic treatment liquid containing a dichromate ion and a metal cation, the second chamber is fed with a first acid aqueous solution, and the third chamber is fed with a second acid aqueous solution, a voltage is applied using the first electrode as an anode and the second electrode as a cathode.

The presently disclosed concepts relate to improved techniques for alkali metal extraction (and in particular lithium), using a solid electrolyte membrane. By using a solid electrolyte embedded in a matrix, alkali metal (such as lithium) can be more effectively separated from feed solutions. Additionally, energy used to initially extract lithium from a feed solution may be stored as electrochemical energy, which in turn, may be discharged when lithium is depleted from the electrode. This discharged energy may therefore be reclaimed and reused to extract additional lithium.

Non-gas emitting electrodes having a very high surface area, high electric capacitance, and low electric resistance are integrated with silver and/or silver chloride for use in electrodialysis/electrodeionization cells, or in any other system requiring the generation of electric fields through electrolyte solutions, and are capable of generating an electric field for extensive periods of time without generation of gases, and without the occurrence of water splitting electrode reactions. Each electrode is highly porous and highly conductive, such as a carbon aerogel electrode, and thus has a very large internal surface area, which is infused with silver and/or silver chloride. This combination supercapacitor and pseudocapacitor electrode can sustain electrode reactions for longer periods of time, and at much higher current densities, as compared to conventional (solid) silver/silver chloride electrodes.