Between two juxtaposed similar ion exchange membranes (AEMs or CEMs), an ion depletion zone and ion enrichment zone 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 use of a sacrificial metal anode allows electrocoagulation (EC) concurrently with ICP thereby permitting concentration of both ionic and non-ionic impurities to occur at the same time within the same cell or device.

Processes, systems, and techniques for multivalent ion desalination of a feed water use an apparatus that has a cathode, an anode, and an electrodialysis cell located between the cathode and anode. The cell has a product chamber through which the feed water flows, a multivalent cation concentrating chamber on a cathodic side of the product chamber through which the concentrated multivalent cation solution flows, and a multivalent anion concentrating chamber on an anodic side of the product chamber through which the concentrated multivalent anion solution flows. The product chamber and the multivalent cation concentrating chamber are each bounded by and share a cation exchange membrane, and the product chamber and the multivalent anion concentrating chamber are each bounded by and share an anion exchange membrane. A monovalent ion species is added to at least one of the concentrated multivalent cation solution and the concentrated multivalent anion solution.

Between two juxtaposed similar ion exchange membranes (AEMs or CEMs), an ion depletion zone and ion enrichment zone 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 use of a sacrificial metal anode allows electrocoagulation (EC) concurrently with ICP thereby permitting concentration of both ionic and non-ionic impurities to occur at the same time within the same cell or device.

A method and system for reducing ion concentration of a solution and converting gas. The system comprising a multi-chamber unitary dialysis cell comprising a gas chamber, a product chamber, and an acid chamber. Ion exchange barriers separate the chambers of the dialysis cell. A first anion exchange barrier is positioned between the product chamber and the acid chamber and a first cation exchange barrier is positioned between the product chamber and the gas chamber. Anions from the solution being treated associate with cations from the acid chamber to form an acid solution in the acid chamber, and cations from the solution being treated associate with anions from the fluid comprising gas to form salt, thereby reducing the ion concentration of the solution being treated and converting at least a portion of the gas into salt.

The present disclosure describes an electrochemical system and methods for the selective separation and simultaneous recovery of ionic constituents in a feed-, raw-, or wastewater. The system entails novel electrochemical configurations comprising various ion exchange membranes in concert with a voltage applied across a pair of electrodes. In some embodiments, the novel electrochemical system may include one or more of a pair of electrodes, a first membrane selectively permeable to a first wastewater constituent, a second membrane selectively permeable to a second wastewater constituent, a third membrane selectively permeable to a third wastewater constituent, a fourth membrane impermeable to ions that allows for the separation of a fourth constituent by preventing mixing between first and third product channels when a plurality of membrane stacks are utilized, and at least four spacing frames comprising a structural element, a gasket, and a flow channel.