Abstract: A zero-gap type electrolytic cell 11 characterized as having a hydrophilic liquid-permeable material 16 interposed between an ion-exchange membrane 12 and a gas diffusion cathode 17. The reaction product passes through the liquid-permeable material and disperses toward edges of the liquid-permeable material before being withdrawn. Hence, the withdrawal direction for the target reaction product is not opposite the feed direction for the reactant gas.

Abstract: An electrolytic cell for producing an alkali hydroxide using a gas diffusion cathode. A moistened oxygen-containing gas is uniformly supplied to the surface of the gas diffusion cathode by means of a gas distributing mechanism, such as at least one gas diffuser pipe having a plurality of openings facing the cathode surface.

Abstract: A seawater electrolysis apparatus for generating hydrogen peroxide from seawater by electrolysis to thereby treat the seawater. The seawater electrolysis apparatus comprises an electrolytic cell, a gas diffusion electrode partitioning the electrolytic cell into a gas chamber and an electrolysis chamber, an insoluble metal electrode disposed in the electrolysis chamber as an anode, an inlet and an outlet for passing seawater through the electrolysis chamber, an inlet for supplying an oxygen-containing gas to the gas chamber, and means for passing and diffusing at least part of the gas supplied to the gas chamber passing through the gas diffusion electrode and into the seawater, respectively.

Abstract: An electrolytic process and apparatus which can operate in a hydrogen reaction chamber at a hydrogen reaction rate corresponding to the increase in the rate of production of hydrogen accompanying the increase in the electrolysis rate and maintain the current efficiency at a very high value with respect to the electrolytic current for producing hydrogen and a process for the production of an electrode for this purpose.

Abstract: An on-site process and apparatus for producing hydrogen peroxide at a high efficiency substantially from brine and oxygen-containing gas alone as raw materials while removing alkaline earth metals. Sea water concentrated by an electrodialytic apparatus 2 or the like as a raw material is supplied to an impurity removing apparatus 10 where caustic soda produced in an acid-alkali producing apparatus 11 at a subsequent stage and/or carbon dioxide gas is added to remove alkaline earth metals contained in sea water in the form of a hydroxide or carbonate precipitate. Separately, the acid-alkali producing apparatus 11 performs a salt separating operation to produce caustic soda which is then supplied to a hydrogen peroxide generator 28 to produce an alkaline aqueous solution of hydrogen peroxide.

Abstract: An electrolytic cell for producing acidic water and alkaline water is disclosed. High-purity acidic water and high-purity alkaline water can be produced in a well balanced proportion from ultrapure water which is supplied in the minimum amount necessary for producing the desired acidic and alkaline waters using the minimum amount of electricity. The electrolytic cell includes an electrolytic acidic-water production unit 3 comprising an anode chamber 6 and an auxiliary cathode chamber 7 separated therefrom by a first ion-exchange membrane 5, and an electrolytic alkaline-water production unit 4 comprising a cathode chamber 10 and an auxiliary anode chamber 9 separated therefrom by a second ion-exchange membrane 8. Separately controllable power supplies are also provided for supplying power to each of the two units. The supply amount of pure water and the amount of electricity used can be fixed according to the desired amounts of acidic and alkaline waters.

Abstract: A method of electrolytically producing acid water using an electrolytic cell partitioned by a cation-exchange membrane into an anode chamber and a cathode chamber. Chloride ion which generates hypochlorous acid by anodic oxidation is supplied to the cathode chamber without directly supplying chloride ion to the anode chamber. Part of the chloride ion permeates from the cathode chamber into the anode chamber through the cation-exchange membrane. The chloride ion which permeates through the cation-exchange membrane is present at the surface of an anode closely adhering to the cation-exchange membrane in the anode chamber or only in the vicinity of the anode, and is efficiently anodically oxidized to form hypochlorite ion. Also disclosed is an electrolytic cell for carrying out the method of electrolytically producing acid water.

Abstract: A gas-diffusion electrode (cathode) in contact with an ion-exchange membrane partitioning an electrolytic cell for producing caustic soda, etc., by electrolysis into an anode chamber and a cathode chamber (gas chamber). The gas-diffusion electrode is divided into plural electrode members in the horizontal direction with an interval provided between adjacent electrode members. Electrolyte guide plates may be disposed on the electrode members or between the adjacent electrode members. An aqueous caustic soda solution formed in the electrolysis smoothly is removed from the gas-diffusion electrode without clogging the electrode.

Abstract: An electrode for electrolysis comprising an electrode base material and an electrode substance having an electrically conductive diamond structure covering the surface of the electrode base material. The electrode substance having an electrically conductive diamond structure may be a diamond containing an impurity selected from boron, phosphorus and graphite. Alternatively, the electrode substance having an electrically conductive diamond structure may comprise a composite of a diamond and an electrically conductive material. In a preferred embodiment, the electrode further comprises an interlayer comprising at least one of the carbide of a valve metal and silicon carbide disposed between the electrode base material and the electrode substance having an electrically conductive diamond structure. Also disclosed is an electrolytic cell having two chambers including an anode chamber and a cathode chamber partitioned by an ion-exchange membrane.

Abstract: A gas-diffusion cathode disposed in contact with an ion-exchange membrane partitioning an electrolytic cell into an anode chamber and a cathode chamber, wherein at least one guide piece is disposed in the gas-diffusion cathode and a salt water electrolytic cell using the above-described gas-diffusion cathode. By using the above-described gas-diffusion cathode for salt water electrolysis, an aqueous caustic alkali solution formed descending in the direction of gravity in the cathode changes direction of movement by contact with a guide piece, whereby the decreased electrode performance resulting from the hindrance of the supply of raw material gas and the discharge of the gas formed caused by the retention of the descending caustic alkali solution is prevented and a large-sized electrolytic cell can be used without problems generally encountered in conventional electrolytic systems.

Abstract: A liquid-permeable gas-diffusion cathode adapted for caustic soda electrolysis in contact with an ion-exchange membrane partitioning an electrolytic cell into an anode chamber and a cathode gas chamber. Plural horizontal concave grooves and/or convex portions are provided in an interval with one another on the surface of the gas-diffusion cathode facing the gas chamber. Plural vertical concave grooves may also be provided in an interval on the surface of the cathode crossing the horizontal grooves and/or convex portions. Aqueous caustic soda solution thus formed flows downward along the grooves, etc., without covering other portions of the cathode surface, and is easily released therefrom without clogging perforations in the gas-diffusion layer of the cathode.

Abstract: An electrolytic cell for producing sodium hydroxide, etc., which is partitioned by an ion-exchange membrane into an anode chamber and a cathode chamber, wherein at least one of a anode and a cathode is closely contacted to the ion-exchange membrane to form a gas diffusion electrode, and a current supplying means having guides for removing sodium hydroxide, etc., formed at the surface of the gas diffusion electrode is disposed therein closely contacting the gas diffusion electrode.By having a current supplying means having removing guides, sodium hydroxide formed at the surface of the gas diffusion electrode is separated therefrom and removed, whereby the supply of the raw material gas and removal of the produced gas can be smoothly performed without clogging perforations of the gas diffusion electrode with the sodium hydroxide.

Abstract: A method of producing a gas diffusion electrode by forming a thin layer comprising a carbon power and a silver powder on the surface of a substrate comprising silver, copper, nickel or stainless steel and fluorinating the thin layer make the carbon water repellent.The gas diffusion electrode can be stably used for a long period of time in sodium chloride electrolysis, etc., without clogging the passage of gas and lowering the water repellency of the electrode.

Abstract: A gas diffusion electrode is constituted by forming a porous layer comprising a super-fine particle catalyst of silver or gold and a fluorine-containing material on a substrate and connecting a gas-liquid permeable collector to the substrate.The gas diffusion electrode can be used stably as an oxygen cathode for a sodium chloride electrolysis, etc., for a long period of time without causing decreased water repellency of the fluorine-containing material in the gas diffusion electrode and without lowering the activity of the electrode substance.

Abstract: A salt water electrolysis process for electrolyzing an aqueous alkali chloride solution capable of preventing the deterioration of a gas diffusion cathode is disclosed. A cation-exchange membrane having closely disposed to one surface thereof an insoluble metal anode and having closely adhered or mechanically attached to the opposite surface thereof a liquid permeable gas diffusion cathode is disposed in an electrolytic cell, and electrolysis is carried out while supplying salt water to the anode chamber and an oxygen-containing gas containing water as steam or fine water droplets to the cathode chamber, and an alkali hydroxide is obtained from the cathode chamber. The water-containing gas directly reaches the gas diffusion cathode and since the alkali hydroxide and the alkali carbonate formed at the surface of the cathode are dissolved in the water in the gas and removed from the electrolytic cell, deterioration of the gas diffusion cathode can be prevented.

Abstract: The present invention relates to an electrolytic electrode comprising a core material made of a valve metal, a dense electrically conductive tin oxide layer formed on the core material, an .alpha.-lead dioxide layer formed on the tin oxide layer, and a .beta.-lead dioxide layer formed on the .alpha.-lead dioxide layer. The present invention also relates to a method for preparing the electrolytic electrode.

Abstract: An electrolytic cell for obtaining a caustic alkali by closely contacting a gas diffusion electrode comprising a gas-liquid permeable metal substrate and a gas-liquid permeable collector connected to the substrate to a cation-exchange membrane while supplying an oxygen-containing gas from the opposite side of the cation-exchange membrane. Grooves for taking out a liquid containing a caustic alkali are formed in the contact surface of the gas diffusion electrode with the cation-exchange membrane.By the formation of the grooves, clogging of the perforations of the gas diffusion electrode with the caustic alkali so formed is prevented, whereby the gas supply can be smoothly carried out and the electrolysis can be stably carried out without reducing the cell voltage.

Abstract: An electrode structure containing an insoluble metal electrode which is used as an electrode for the electrolysis of an acidic aqueous solution under a high current density is disclosed. An elastic electroconductive material, containing an expanded metal, having formed thereon a corrosion-resistant electroconductive coating, is disposed between an electroconductive electrode substrate and an electrode having on the surface thereof a coating of an electrode material. They are fixed by a detachable fixing device from the surface of the electrode. The electrode can be exchanged when fixing the electrode structure to the electrolytic cell.

Abstract: There are provided an ozone water treatment method by comprising the steps of injecting an ozone-containing gas into pure water to prepare ozone water, supplying the ozone water to use point(s) for treatment of materials to be treated, and circulating for reuse or discharging the ozone water after use, which comprises disposing a deozonizing apparatus, the inside of which is divided into an ozone water passing zone and a reduced pressure zone by a diaphragm, at the downstream side of the use point(s), supplying the ozone water after use to the ozone water passing zone of the deozonizing apparatus, and removing residual ozone and residual oxygen in the ozone water after use by contacting the water with the reduced pressure zone through the diaphragm and an apparatus utilized in the ozone treatment method.

Abstract: An electrolytic ozone generator comprising anode chamber 3 and cathode chamber 4 partitioned by solid electrolyte 2, in which deionized water is electrolyzed in the cathode chamber while feeding air or oxygen-rich air to the cathode chamber through, for example, air holes 14. The air fed suppresses evolution of hydrogen gas thereby affording a saving of energy and eliminating the need a separate cooling mechanism. Furthermore, the air also decomposes ozone having entered the catholyte.