Abstract: An electrode for use in electrochemical ion exchange comprises an electrically conducting element covered by at least two layers of ion exchange material. The material in one layer differs in its electrical, chemical, or ion exchange properties from that in an adjacent layer. For example a thin layer of cation exchange material underneath a thicker layer of anion exchange material may be used to inhibit the oxidation of chloride ions; a thin layer of cation exchange material covering a thicker layer of anion exchange material provides an anion-responsive electrode with enhanced selectivity for particular ions. An ion-selective anion-responsive electrode can also comprise a thin outer layer of a very weak base anion-responsive material, covering a thicker layer of a strong base material of lower electrical resistivity.

Abstract: An apparatus for treating a liquid by electrochemical ion exchange comprises a flow channel (34) in which are arranged a cation-responsive ion exchange electrode (38) side by side with an anion-responsive ion exchange electrode (42), with a counter electrode (40,44) between them. By controlling the currents to the two ion exchange electrodes (38,42) independently, the pH of the treated liquid can be controlled at a desired value.

Abstract: A first metal, for example a transition metal such as cobalt, having an insoluble hydroxide is separated from a second metal such as lithium having a soluble hydroxide in an aqueous liquid containing dissolved cations of the metals. The cations are firstly absorbed onto a cation exchange material by electrochemical ion exchange and the second metal then selectively eluted by electrochemical ion exchange under sufficiently high pH conditions, e.g. to 10-13, in a closed loop. Finally, the transition metal is eluted by electrochemical ion exchange under sufficiently low pH conditions, e.g. acidic such as 1-2. The method is applicable to separating trace quantities of Co (e.g. as Co-60) from larger quantities of Li in aqueous solution.

Abstract: An electrode used in electrochemical deionization comprises a current feeder disposed asymmetrically in an ion exchange material bonded into a coherant structure i.e. more of the ion exchange material adheres to one side of the current feeder than to the other side. The ion exchange material may be bonded by being provided in intimate admixture with a binder. Such an electrode offers manufacturing ease and the ability to be scaled up in multi-modular form.

Abstract: Ions are electrochemically removed from an aqueous solution by establishing an electrochemical cell wherein the solution, as cell electrolyte, is caused to flow between a working electrode that includes an ion exchange material and a second electrode that optionally includes an ion exchange material. The polarity of the cell is repeatedly reversed so that ions are successively adsorbed and desorbed at the working electrode and optionally also at the second electrode. Thus, an ion for removal such as Cs.sup.+ may be selectively removed in the presence of a much larger concentration of a second ion such as Na.sup.+.

Abstract: An electrochemical extraction method comprises establishing a cell of the form working electrode: flowing aqueous electrolyte solution: second electrode. The working electrode includes an ion exchange material and the second electrode may include ion exchange material. D.C. potential is applied to the cell to adsorb ions onto the working electrode and cell polarity is subsequently reversed to elute the adsorbed ions.The cell is separated by a cell divider, e.g. in the form of an ion selective membrane, into first and second electrolyte compartments and the solution is passed through the compartment adjacent the working electrode to effect adsorption and, where the second electrode includes ion exchange material, solution is passed through the compartment adjacent the second electrode to effect desorption.

Abstract: An electrode for use in electrochemical deionization comprises a current feeder support carrying an intimate mixture of an ion exchange material, and a binder.The electrode is provided with an inert, electrolyte-permeable outer envelope, adhered to the mixture, for maintaining the mixture in contact with the current feeder during use of the electrode in electrochemical ion exchange. The envelope may be in the form of a non-woven polyamide cloth and may be provided with an outer restrainer, e.g. in the form of a metal or plastics mesh.

Abstract: A positive electrode for a lead acid electric storage cell is made by chemically preparing beta lead dioxide. The beta lead dioxide is then applied to a support structure with a binder, or poured into a permeable, tubular container located about a current collecting rod. The negative electrode can be made by compacting fine lead metal about a carrier, and the fine lead metal might comprise lead wool or particulate lead metal.