Abstract: A process for electrolyzing an aqueous solution of hydrochloric acid to chlorine in an electrochemical cell provided with an anode compartment and a cathode compartment including at least one gas diffusion cathode comprising an electrically conductive web provided on at least one side thereof with a coating of a catalyst for the electroreduction of oxygen comprising rhodium sulfide and optionally containing at least one fluorinated binder incorporated therein, comprising introducing aqueous hydrochloric acid containing contaminant species into the anode compartment and oxygen into the cathode compartment while impressing a direct electric current on the cell.

Abstract: The invention relates to a process for electrochemically converting anhydrous hydrogen halide, such as hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to essentially dry halogen gas, such as chlorine, fluorine, bromine and iodine gas, respectively. In a preferred embodiment, the present invention relates to a process for electrochemically converting anhydrous hydrogen chloride to essentially dry chlorine gas. This process allows the production of high-purity chlorine gas. In this process, molecules of essentially anhydrous hydrogen chloride are transported through an inlet of an electrochemical cell. The molecules of the essentially anhydrous hydrogen chloride are oxidized at the anode of the cell to produce essentially dry chlorine gas and protons, which are transported through the membrane of the cell. The transported protons are reduced at the cathode to form either hydrogen gas, water or hydrogen peroxide.

Abstract: Method and apparatus for optimizing the electrolytic production of a halogen in a water treatment system having a halogen salt dissolved therein. The flow rate to the electrolytic cell is maintained below a predetermined maximum beyond which the remaining flow is diverted from the cell. The flow going to the cell is monitored for flow rate, water temperature and conductivity and the operation of the electrolytic cell is adjusted in response.

Abstract: A halogen generator produces a halogen sanitizing agent to sanitize water in a spa or other water feature. A coaxial wall fitting desirably couples the halogen generator to the water feature. The halogen generator desirably includes a bipolar electrolytic cell in which a center electrode plate rotates between stationary anode and cathode plates. The bipolar electrode includes a plurality of vanes which motivate water flow between the anode and the cathode. The vanes on the rotating electrode also produce a flow of water through the generator. In this manner, the bipolar electrode functions as a impeller to pump water through the halogen generator. The vanes are positioned between the electrode and cathode, and are sufficiently spaced from the cathode to inhibit scale formation on the cathode. The vanes, however, generally do not contact the cathode when rotating.

Abstract: An alkaline peroxide cell for electrolytic regeneration of spent BHP from a chemical oxygen iodine laser, the cell having a for regenerating chlorine and a peroxide cell for regenerating BHP. The chlorine compartment having a potassium chloride electrolyte and producing chlorine gas for the chemical oxygen iodine laser. The peroxide cell having a spent BHP electrolyte and producing BHP for the chemical oxygen iodine laser. A cation exchange membrane between the chlorine compartment and the peroxide compartment allows potassium ions to be transported from the chlorine compartment to the peroxide compartment.

Abstract: The present invention relates to an electrochemical cell, system and process for converting essentially anhydrous hydrogen halide to essentially dry halogen gas. The process of the present invention is useful for converting anhydrous hydrogen halide, in particular, hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to a halogen gas, such as chlorine, fluorine, bromine, or iodine. In particular, in the present invention, water is provided to the cation-transporting membrane at the cathode in various ways. The present invention allows for recovery of a released fluid at the cathode-side of the membrane and recycling of the released fluid back to the cathode side of the membrane. In this way, the recovered, released fluid may be recycled to continuously supply water to the membrane, thereby allowing the limiting current density of the cell to be increased and/or controlled.

Abstract: A gas diffusion electrode comprising an electrically conductive web provided on at least one side thereof with a coating containing a rhodium--rhodium oxide catalyst on a carbon black support and a method for the preparation of the rhodium--rhodium oxide catalyst.

Abstract: A low temperature method and apparatus for removing halides from relatively low temperature gas mixtures (below about 150.degree. C.) using an electrochemical cell provided with inert electrodes and an electrolyte which will provide anions compatible with the halide anions formed at the anode. The electrolyte is elected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the halides are converted to X.sup.-. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels. Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Abstract: A fluid delivery device (10) operated by a first gas delivery device (12) (e.g. electrochemical pump) that takes advantage of sequential gas production methods. The fluid delivery device includes a container (14) with an interior surface. An first gas delivery device for producing or delivering a first gas is placed in one end of the container. A moveable member (e.g. piston, bladder (18) or membrane) is positioned within the container, which moveable member, together with the container's interior surface and the electrochemical cell, structurally define a fluid-tight chamber. The moveable member may abut a first reactive material. Unreacted material (34), chemically reactive with the either the first gas or the first reactive material to generate a second gas, is contained within the container.

Abstract: A method and apparatus for removing halides from high temperature gas mixtures (150.degree.-1000.degree. C.) using an electrochemical cell provided with inert electrodes and an electrolyte which will provide anions compatible with the halide anions formed at the anode. The electrolyte is elected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the halides are converted to X.sup.-. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels. Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Abstract: The invention relates to a process for treating a low-concentrated aqueous feed solution which includes at least one aqueous process stream from a pulp mill. The process includes concentrating the feed solution by evaporation to form an evaporation concentrate, and subjecting at least a part of the concentrate to a first electrodialysis treatment, thereby forming a first electrodialysis concentrate containing salt removed from the evaporation concentrate and at least one diluate depleted in the salt. The invention also relates to a plant for carrying out the above process.

Abstract: A water electrolyzer for electrolyzing water to produce and recover acidic and/or alkaline water. The electrolyzer is of the membraneless laminar-flow type which is designed to electrolyze water without placing a membrane between the electrodes. To this end, the anode and cathode are arranged closely with one another with a very small spacing (generally less than 1 mm) to establish a laminar flow in a narrow flow path. The anode is provided with a slit-shaped aperture for separating a thin layer of acidic water flowing along the anode surface. This aperture is situated sufficiently upstream of the downstream end of the flow path to ensure that the layer of acidic water is separated away from the remainder of the laminar flow while the laminar flow is sustained in the flow path. Accordingly, formation of turbulence at a point of acidic water separation is minimized so that highly acidic water can be recovered.

Abstract: The invention relates to a process for electrochemically converting anhydrous hydrogen halide, such as hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to essentially dry halogen gas, such as chlorine, fluorine, bromine and iodine gas, respectively. In a preferred embodiment, the present invention relates to a process for electrochemically converting anhydrous hydrogen chloride to essentially dry chlorine gas. This process allows the production of high-purity chlorine gas. In this process, molecules of essentially anhydrous hydrogen chloride are transported through an inlet of an electrochemical cell. The molecules of the essentially anhydrous hydrogen chloride are oxidized at the anode of the cell to produce essentially dry chlorine gas and protons, which are transported through the membrane of the cell. The transported protons are reduced at the cathode to form either hydrogen gas or water.

Abstract: An easily installed, automatically operated sanitizing direct current, electrolytic cell canister assembly and a method or efficiently providing brominated water for swimming pools and the like, the method including furnishing d.c. power at a constant amperage to the bipolar electrode graphite plate electrolytic cell canister, controlling the flow of electrolyte through the canister, turning the d.c. current on and off to provide d.c. on/off switching, turning the d.c. power off, adjusting the time of the on/off switching so that the current is off for a predetermined selected time in a cycle of about 1 to 60 seconds, and, just prior to reversing the polarity of the electrodes, turning the power off for about five seconds, with separate polarity changing switching to help efficiently clean the graphite plates and keep the bromine atoms from going back to their ionized state and reduce any power surge due to the reversal of the polarity.