Membrane-electrode assembly, electrolytic cell employing the same, electrolytic-water sprayer, and method of sterilization

Abstract

The present invention provides a membrane-electrode assembly which comprises: at least one rod-form or tubular electrode; a tubular diaphragm disposed around the periphery of the electrode; and a wire-form counter electrode disposed around the periphery of the diaphragm, the diaphragm being fixed to the rod-form or tubular electrode with the wire-form counter electrode to thereby form an electrode chamber having a gas / liquid passage between the diaphragm and the rod-form or tubular electrode.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a membrane-electrode assembly for yielding electrolytic water to be used for sterilization, cleaning, etc., an electrolytic cell employing the assembly, an electrolytic-water sprayer including any of the electrolytic cell, and a method of sterilization using these.BACKGROUND OF THE INVENTIONBactericide / Disinfectant Solution:[0002]Chlorine compound bactericides such as sodium hypochlorite, calcium hypochlorite, and sodium dichloroisocyanurate have been extensively used as bactericides / disinfectants in a wide range of environments. Of these, hypochlorites including sodium hypochlorite are in general use from the standpoints of cost and effect. However, many proposals have been made for attaining improvements in the bactericidal / disinfectant effect thereof which are required in various fields including the clinical field and the food industry (see, for example, JP-A-2001-253803, JP-A-2001-342496, and JP-A-2002-145710).[0003]U...

AI Technical Summary

Benefits of technology

[0045](1) Although use of an ion-exchange membrane or the like improves ionic conductivity and this is expected to increase electrolysis reaction efficiency, it has been difficult to join the membrane or the like with the electrodes.

[0051]An object of the invention is to provide a membrane-electrode assembly with which many of those problems can be eliminated and which can be easily produced and bring about high performance. Another object of the invention is to provide an electrolytic cell and an electrolytic-water sprayer, each employing the assembly, and a method of sterilization. The electrolytic-water sprayer of the invention electrolyzes a raw aqueous solution, and the electrolytic water thus yielded can be immediately utilized.

[0072]A membrane-electrode assembly having an ideal passage is obtained by suitably selecting the diameter and number of the rod anode, diameter of the tubular membrane, and material, thickness, and winding pitch of the wire cathode. In particular, by spirally winding the wire cathode at a pitch of 1-10 mm, an assembly having a suitable structure is obtained. It is especially preferred that the anode should be diamond, because this assembly can efficiently generate ozone, etc.

[0078]In those electrolytic cells, an active species such as ozone is efficiently synthesized in a high concentration to yield electrolytic water having a sterilizing / bleaching ability. The concentration of ozone or another species in the electrolytic water depends on the amount of raw water flowing through each chamber per unit time period. The area of the section through which raw water flows can be regulated by regulating the diameter and number of the rod anode, diameter of the tubular membrane, and winding pitch of the wire cathode. Thus, electrolytic water can be efficiently produced.

[0084](4) Novel composite electrolytic water (having a novel sterilizing effect brought about by adding an organic acid or surfactant for pH regulation for the purpose of improving bactericidal activity or by adding an alcohol or the like for the purpose of, e.g., improving bactericidal activity or refreshing feeling)

[0085]In the membrane-electrode assembly produced by disposing, in a tube-forming manner, a sheet-form ion-exchange membrane or the like around the periphery of at least one rod electrode and disposing a wire-form counter electrode or a porous counter electrode therearound, the rod electrode, membrane, and counter electrode have been united together. Because of this, the assembly once produced can be easily handled. This assembly can be easily produced.

Problems solved by technology

(1) Although use of an ion-exchange membrane or the like improves ionic conductivity and this is expected to increase electrolysis reaction efficiency, it has been difficult to join the membrane or the like with the electrodes.

(2) The membrane usually is nonporous and is used usually in combination with porous electrodes for facilitating the feeling of an electrolytic solution and removal of products. The shape of the electrode assembly is hence complicated.

(3) When the assembly is to be attached to an apparatus, the piping membranes are frequently cylindrical and, hence, the electrodes preferably have a shape suitable for the piping members, i.e., a rod-form or cylindrical shape. It has been necessary to employ an apparatus suitable for that shape.

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