The present invention relates to a separation device or system using a separation membrane, as a method of separating impurity ions other than hypochlorous acid from an aqueous solution containing hypochlorous acid as a main component, and provides a solution containing hypochlorous acid as a main component, having more excellent storage stability.

The present disclosure provides a system for capturing carbon from air based on bipolar membrane electrodialysis, which includes a first cation exchange membrane, a bipolar membrane and a second cation exchange membrane arranged in sequence, where a desorption chamber is arranged between the first cation exchange membrane and the bipolar membrane, and an absorption chamber is arranged between the bipolar membrane and the second cation exchange membrane; and a cathode reaction chamber is arranged on the other side of the first cation exchange membrane, and an anode reaction chamber is arranged on the other side of the second cation exchange membrane. The system improves carbon capture rate and capture purity, and can be adapted to various scenarios.

An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO.sub.2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then tested and processed (e.g., mixed/diluted with processed feedstock solution, seawater or another saltwater solution and/or reacted with CO.sub.2) to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when supplying the alkalinity product will not endanger sea life. Modified BPED systems include features that facilitate autonomous system operations including enhanced maintenance cycle operations and a reduced reliance on external fresh water sources.

Methods for controlling electrolyte chemistry in electrodialysis units having an anode and a cathode each in an electrolyte of a selected concentration and a membrane stack disposed therebetween. The membrane stack includes pairs of cationic selective and anionic membranes to segregate increasingly dilute salts streams from concentrated salts stream. Electrolyte chemistry control is via use of at least one of following techniques: a single calcium exclusionary cationic selective membrane at a cathode cell boundary, an exclusionary membrane configured as a hydraulically isolated scavenger cell, a multivalent scavenger co-electrolyte and combinations thereof.

Methods for controlling electrolyte chemistry in electrodialysis units having an anode and a cathode each in an electrolyte of a selected concentration and a membrane stack disposed therebetween. The membrane stack includes pairs of cationic selective and anionic membranes to segregate increasingly dilute salts streams from concentrated salts stream. Electrolyte chemistry control is via use of at least one of following techniques: a single calcium exclusionary cationic selective membrane at a cathode cell boundary, an exclusionary membrane configured as a hydraulically isolated scavenger cell, a multivalent scavenger co-electrolyte and combinations thereof.

Water treatment systems including electrically-driven and pressure-driven separation apparatus configured to produce a first treated water suitable for use as irrigation water and a second treated water suitable for use as potable water from brackish water and methods of operation of same.

Water treatment systems including electrically-driven and pressure-driven separation apparatus configured to produce a first treated water suitable for use as irrigation water and a second treated water suitable for use as potable water from brackish or saline water and methods of operation of same.

Between two juxtaposed similar ion exchange membranes (AEMs or CEMs), an ion depletion zone (d.sub.de) and ion enrichment zone (d.sub.en) are generated under an electric field. As cations are selectively transferred through the CEMs, for example, anions are relocated in order to achieve electro-neutrality, resulting in the concentration drop (increase) in ion depletion (enrichment) zone. The concentration drop (i.e. salt removal) is low and spatially gradual at relatively low voltage or current (i.e. Ohmic regime). However, at higher voltage or current (i.e. overlimiting regime), strong electroconvective vortex accelerates cation transport through CEMs, allowing us to “relocate” most salt ions. The flat depletion zone occurs with significantly low ion concentration, and corresponding strong electric field in the zone, and any charged agents (e.g. proteins and bacteria) cannot penetrate this flat zone. As a result, we can separate and collect the desalted/purified flow from brine flow by bifurcating the channel at the end of the CEMs. This ICP desalination/purification also happens with two anion exchange membranes (AEMs) by relocating cations, but the location of desalted/brine flows are converted.

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.