TWI535894B - Electrolysis system and electrolysis method for the same - Google Patents

Description

Electrolytic device and electrolysis method

The present invention relates to an electrolysis device and an electrolysis method using a non-refined water containing a trace amount of an alkaline earth metal ion such as calcium or magnesium as a raw material, and supplying the raw material water to a cathode chamber, thereby preventing precipitation of the alkali on the surface of the cathode Electrolyzing device and electrolysis method for scaling of hydroxides of earth metals.

The water treatment system using the electrolytic reaction is widely practiced for the purpose of performing electrolysis such as production of functional water, ozone water, and electrolyzed water, or sterilization, decomposition and removal of harmful substances, and the like. The reaction tanks used in these processes generally have a structure in which an anode, a cathode, and an ion exchange membrane or a porous separator interposed therebetween are housed in a casing, and are generally referred to as "electrolyzers" or "electrolytic cells". . Such an electrolytic cell or an electrolytic cell is composed of a separator, an anode chamber partitioned by the diaphragm, a cathode chamber partitioned by the diaphragm, an anode provided in the anode chamber, and a cathode provided in the cathode chamber. There are known two-slot type electrolyzers and three-slot type electrolyzers.

The double-slot type electrolyzer is a solid-state polymer electrolyte type electrolysis apparatus such as a diaphragm electrolysis apparatus, a cation exchange membrane electrolysis apparatus, and a special method.

The diaphragm electrolysis device is a separator using a porous separator; and the cation exchange membrane electrolysis device is a separator using a cation exchange membrane; and the solid polymer electrolyte type electrolysis device is attached to both sides of the cation exchange membrane. The cathode is used, and the cation exchange membrane is used as a solid polymer electrolyte (Solid Polymer Electrolyte) to constitute an electrolysis device which can be electrolyzed even with pure water having a small conductivity. Further, the three-slot type electrolyzer has a separator that separates the anode chamber from the cathode chamber, and a cation exchange membrane and an anion exchange membrane are disposed between the anode chamber and the cathode chamber, and an intermediate is formed between the cation exchange membrane and the anion exchange membrane. room. These electrolyzers can generate various functional waters and ozone water.

The present invention relates to an electrolysis device and an electrolysis method using non-refined water containing a trace amount of an alkaline earth metal ion such as calcium or magnesium as a raw material, and more specifically, the present invention proposes that the raw material water is a non-refined water. The ozone water production device and the ozone water production method, the functional water production device, the functional water production method, the electrolysis water production device, the electrolysis water production method, the sterilization method, the wastewater treatment method, and the like by electrolysis, and the reduction of the cathode such as hydrogen Apparatus and method for causing problems such as oxides and the like. Further, according to the electrolysis device and the electrolysis method of the present invention, it is expected that the same problem as other uses can be solved.

In general, in the manufacturing step of the waste liquid treatment step or the so-called "alkaline ion water", the raw material is a non-refined water containing an alkaline earth metal ion such as calcium ion or magnesium ion. Electrolysis using such non-refined water will proceed with the progress of electrolysis, first increasing the pH of the catholyte from the surface of the cathode, resulting in the presence of trace amounts of calcium-based alkaline earth metal ions in the raw material water, which will form non-conductive scale. (Scaling), i.e., such hydroxides, oxides, and carbonates, are deposited on the cathode surface, making it difficult to continue to electrolyze frequently.

Therefore, Patent Document 1 and Patent Document 2 propose the use of a cathode chamber liquid system. The acid method, in addition to its complicated structure, also imposes a burden on operational safety management. Further, in Patent Document 3, it is proposed to provide a preliminary tank and a plurality of electrode groups in the apparatus for producing electrolyzed water, and to switch the use of the preliminary tanks at predetermined times to suppress the cathode deposits, which is a cause of an increase in size and cost of the apparatus. Further, Patent Document 4 discloses a method of stopping the operation at regular intervals and removing the deposit by, for example, pickling, but the operation is complicated. Further, Patent Document 5 proposes to prevent the cathode from being precipitated by using an acid cell having no separator to form acidity by using hydrochloric acid, but using a strong acid liquid such as hydrochloric acid is advantageous in terms of safety and cost. And depending on the application, there will be cases where it cannot withstand strong acid use.

On the other hand, Patent Document 6 proposes that when the electrolytic characteristics are deteriorated, the anode/cathode of the electrolytic cell is reversed, and a method of returning the reverse current to the performance is applied. In this case, when such a reverse current flows, the cathode system temporarily acts as an anode and elutes the constituent metal components. The ions of the eluted metal, such as Cr, Ni, and the like, which are contained in the treatment liquid themselves are not only poor, but also penetrate into the solid polymer electrolyte membrane, resulting in a significant deterioration in ion transport ability. Therefore, the cathode system uses a valve metal having a high corrosion resistance. In this case, it is necessary to apply a high-priced precious metal coating to the surface thereof to reduce the electrolytic overvoltage. Further, there is a concern that the cathode of the anode which is temporarily a cathode is reduced, or hydrogen embrittlement derived from the cathode, and the like, may cause deterioration.

Furthermore, according to Patent Document 7, there is a proposal to use on a conductive substrate. On the film forming a lower hydrogen overvoltage, the cathode which is covered by the reduction preventing film is used, and the chloride aqueous solution is used to produce a hypochlorite which is electrolyzed without a separator, and the reduction prevents the film from using organic cation exchange. Membrane, inorganic cation exchange membrane, or a mixture of these. However, this reduction prevents the film from being electrolyzed by a membrane-free method, that is, the method in which the material of the anode is directly contacted to the cathode, to prevent the hypochlorite ion reduction by the cathode, and does not belong to the cathode. A cathode precipitate mainly composed of an alkaline earth metal hydroxide occurs. On the other hand, in the electrolysis method and the electrolysis apparatus using the separator according to the present invention, it is not necessary to prevent the reduction film from being reduced for the hypochlorite ions belonging to the product in the anode as described in Patent Document 7.

In the electrolytic method and the electrolysis device using a separator, when non-refined water containing an alkaline earth metal ion is used as a raw material, the metal ions which become cations and ionize on the surface of the cathode are concentrated, which further causes the pH to rise. As a result, the hydroxide-based scale of the cathode precipitate is formed. Since the formation of the scale may cause a problem that hinders the operation, the conventional method for suppressing the formation of scale is expected to be improved because the corresponding cost and procedure are required, or the negative evaluation such as having to sacrifice part of the performance is considerable.

[Previous Technical Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-173789

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-177671

[Patent Document 3] Japanese Patent Laid-Open No. 2011-050807

[Patent Document 4] Japanese Patent Laid-Open No. Hei 10-130876

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2008-200667

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2008-150665

[Patent Document 7] Japanese Patent Laid-Open No. Hei 8-104991

The object of the present invention is to solve the above-mentioned conventional method, and to provide a method for electrolyzing a separator and an electrolysis device, which can prevent the precipitation of the alkali on the surface of the cathode when non-refined water containing an alkaline earth metal ion is used as a raw material. Electrolyzing device and electrolysis method for scaling of hydroxides of earth metals.

In order to achieve the above object, the first object of the present invention provides an electrolytic device comprising: a separator, an anode chamber partitioned by the separator, a cathode chamber partitioned by the separator, an anode provided in the anode chamber, and a structure comprising a cathode provided in the cathode chamber and supplying a raw material water containing an alkaline earth metal ion to the cathode chamber; wherein the cathode is substantially entirely adhered to by an alkali metal-containing scale containing a cation exchange resin. The film is covered to prevent precipitation of scales such as hydroxides of the alkaline earth metal on the surface of the cathode.

According to a second aspect of the present invention, the diaphragm is a diaphragm-type electrolysis device using a porous separator.

According to a third aspect of the present invention, the diaphragm is cation exchanged. The membrane constitutes a cation exchange membrane electrolysis apparatus.

According to a fourth aspect of the present invention, a solid polymer electrolyte type electrolysis device is formed by closely adhering the anode and the cathode to both surfaces of the cation exchange membrane.

According to a fifth aspect of the present invention, in the separator in which the anode chamber and the cathode chamber are separated, a cation exchange membrane and an anion exchange membrane are provided between the anode chamber and the cathode chamber, and the cation exchange membrane and the anion are provided. An intermediate chamber is formed between the exchange membranes to form a three-slot type electrolysis device.

According to a sixth aspect of the present invention, in the anode of the anode, conductive diamond, lead dioxide, a noble metal, and a noble metal oxide are used.

According to a seventh aspect of the present invention, an electric current-carrying member is provided in the anode and the cathode.

According to the eighth aspect of the present invention, in the film containing the cation exchange resin and preventing the adhesion of the alkaline earth metal scale, a filler composed of a fiber or a powder formed of an inorganic/organic material is mixed and used as the film. Reinforcing agent.

According to a ninth aspect of the present invention, in the film containing the cation exchange resin and preventing the adhesion of the alkaline earth metal scale, ceramic fine particles having a cation exchange ability can be mixed.

According to a ninth aspect of the present invention, in the ceramic fine particles having the cation exchange ability, at least one type of ceramic fine particles selected from the group consisting of an apatite, a perovskite oxide, and a zeolite are used.

According to a seventh aspect of the present invention, in the cathode substrate of the cathode, A plate, a porous metal, a fibrous metal formed body, a mesh, or an apertured punched metal.

According to a fourth aspect of the present invention, in the electrolysis method, the raw material water containing an alkaline earth metal ion such as calcium or magnesium is electrolyzed by using the above electrolysis device.

According to the present invention, when a non-refined water containing an alkaline earth metal ion is used as a raw material by using an electrolysis method and an electrolysis apparatus of a separator, the cathode is substantially entirely utilized by a cation exchange resin-containing coating for preventing adhesion of an alkaline earth metal scale. By coating, even if various means such as the above-mentioned conventional techniques are not employed, deposition such as hydroxide can be suppressed, and the electrolytic voltage derived from the phenomenon can be suppressed from rising. As a result, the present invention can perform a long-term, stable electrolysis operation as compared with the case where it is not carried out in accordance with the present invention.

The reason is that when the film which prevents the adhesion of the alkaline earth metal scale is not used, a trace amount of alkali metal ions (for example, Na ⁺ ) in the raw material water is brought close to the surface of the cathode catalyst, and here the cathode reaction Na ⁺ + H ₂ O+e ^- → NaOH + (1/2) H ₂ makes the surface of the cathode alkaline, and the alkaline earth metal ions such as Ca ²⁺ which form impurities as well as Na ⁺ form Ca on the surface of the cathode catalyst ( OH) ₂ alkali precipitates and becomes fouling and deposits covering the cathode catalyst.

On the other hand, when the present invention coats a film which prevents the adhesion of the alkaline earth metal scale, the NaOH and H ₂ gas generated on the cathode catalyst are diffused to prevent the alkaline earth metal scale formation by the cation exchange resin. The adhered film is oozing out from the surface of the film and diffusing more in the raw material water. At this time, an alkaline earth metal ion (for example, Ca ²⁺ ) which is an impurity and contains as well as Na ⁺ because the transport rate in the cation exchange resin is smaller than Na ⁺ , and thus reaches the cathode catalyst surface opposite to the anode. The alkali precipitates in the vicinity of the surface of the film containing the cation exchange resin to prevent the adhesion of the alkaline earth metal scale, and becomes Ca(OH) ₂ , and the cathode deposit such as Ca(OH) _{2 is} not directly deposited on the cathode contact. On the surface of the media. Moreover, the cathode deposit is deposited not only in the vicinity of the surface of the surface of the anode, but also on the surface of the cathode, which is deposited on the surface of the anode, and is uniformly distributed over the cathode. Visual observation or magnifying glass can be confirmed by observing the cathode after a long period of electrolysis. Accordingly, the surface of the cathode catalyst itself is not directly covered by the Ca(OH) ₂ precipitation layer, and electrolysis will continue. In addition, the hydrogen gas generated from the surface of the cathode is diffused to the outside through a minute gap or the like in the film which prevents the adhesion of the alkaline earth metal scale containing the cation exchange resin.

Further, according to the present invention, it is possible to suppress precipitation of deposits of hydroxides or the like (Ca(OH) ₂ or the like) of the alkaline earth metal on the surface of the cathode, and to prevent scale formation of alkaline earth metals by using a cation exchange resin. When the adhered film covered the cathode, the cathode catalyst was directly contacted with the solution and electrolyzed as compared with the uncovered film, and it was observed that the above-mentioned deposit was weakly adhered to the cathode surface, and most of the film was naturally peeled off. The discharge path of the hydrogen molecules generated on the surface of the cathode to the film containing the cation exchange resin to prevent the adhesion of the alkaline earth metal scale is immediately narrowed, so that the cell voltage eventually rises, but compared with The film which prevents the adhesion of the alkaline earth metal scale containing the cation exchange resin is not used, and the rising speed of the film is particularly moderated under the electrolytic device which covers the cathode.

In addition, when the cathode is integrated, the film which prevents the adhesion of the alkaline earth metal scale containing the cation exchange resin is replaced, and the case is coated by using only the porous resin film having no ion exchange ability such as a fluororesin, because The method of reducing the exposed area of the cathode surface, so that the electrolysis current concentrates on only a few remaining exposed portions, causing the pH to rise sharply. As a result, scales such as non-conductive hydroxides are formed at this portion, causing the cell voltage to rise rapidly, causing a counter effect.

An electrolysis device according to the present invention comprises: a separator, an anode chamber partitioned by the separator, a cathode chamber partitioned by the separator, an anode provided in the anode chamber, and a cathode provided in the cathode chamber, and The cathode chamber is supplied with a raw material water containing an alkaline earth metal ion such as calcium or magnesium; wherein the cathode is substantially entirely covered by a film containing a cation exchange resin for preventing adhesion of an alkaline earth metal scale, and is prevented from being on the surface of the cathode The precipitation of the scale of the above-mentioned alkaline earth metal hydroxide or the like occurs.

The electrolysis apparatus of the present invention is used in a diaphragm electrolysis cell such as a two-channel type electrolysis apparatus and a three-channel type electrolysis apparatus. The two-slot type electrolyzer is a solid state such as a diaphragm electrolysis apparatus, a cation exchange membrane electrolysis apparatus, and a special method. Polymer electrolyte type electrolyzer.

The separator-based electrolysis device uses a porous separator for the separator; the cation exchange membrane-based electrolysis device uses a cation exchange membrane; and the solid polymer electrolyte-based electrolysis device uses the cation exchange membrane as a solid polymer electrolyte (Solid Polymer Electrolyte). The anode and the cathode are closely adhered to both sides thereof to form an electrolysis device which can be electrolyzed even with pure water having a small electrical conductivity. Further, in the three-slot type electrolysis device, a separator that separates the anode chamber from the cathode chamber is provided with a cation exchange membrane and an anion exchange membrane between the anode chamber and the cathode chamber, and between the cation exchange membrane and the anion exchange membrane. Form an intermediate chamber.

Fig. 1 is a cross-sectional view showing a solid polymer electrolyte type electrolysis apparatus which is an example of a double-channel type electrolysis apparatus, wherein a 1 type cathode chamber, a 2 series cathode, a 3 series anode chamber, a 4 series anode, a 5 series cation exchange membrane, and a 6 series cathode 2 The energization member and the energization member of the 7-series anode 4.

Fig. 2(a) shows an example of the anode 4, and the anode substrate 4a of the anode 4 is a porous screen and is coated with an anode catalyst 4b on its surface.

2(b) is a cross-sectional view showing an example of the cathode 2, and the cathode base material 2a of the cathode 2 is the same as the anode base material 4a, and the porous mesh is used, and the organic base metal containing the cation exchange resin is substantially completely covered. The film 8 to which the scale adheres.

The cathode substrate 2a of the cathode 2 is derived from, for example, iron and its alloys including stainless steel, nickel and its alloys, copper and alloys thereof, aluminum and alloys thereof, and titanium, zirconium, The present invention can be applied to molybdenum, tungsten, rhenium, and alloys or carbides, carbons, and allotropes thereof, which are suitable for their respective uses. For the purpose of use, noble metal and noble metal oxides may be suitably used as an electrode catalyst and coated thereon.

In the form of the cathode base material 2a of the cathode 2, a plate material, a perforated punched metal plate, a mesh, a porous metal, a fibrous metal molded body (for example, a tantalum fiber sintered body), or the like can be used, even if other shapes of the substrate are used. In addition, it is expected that the effect of the present invention obtained by coating the effective surface of the cathode base material 2a and the film which prevents the adhesion of the alkaline earth metal scale containing the cation exchange resin can be exhibited without any problem.

The anode base material 4a of the anode 4 is made of a metal such as ruthenium, osmium, titanium, zirconium, and hafnium which forms a stable passivation film in the treated water, and these alloys, and the use thereof, from the viewpoint of reaction catalyst activity, etc. Conductive diamond, lead dioxide, noble metal, and noble metal oxide can be appropriately selected on the surface thereof and used as the anode catalyst 4b and applied to the anode substrate 4a. Further, the anode 4 may be used alone as the anode base material 4a such as ferrite iron, amorphous carbon, graphite or the like.

In order to form the film 8 containing the cation exchange resin and prevent the adhesion of the alkaline earth metal scale substantially on the surface of the cathode base material 2a, the dispersion of the cation exchange resin is applied onto the surface of the cathode base material 2a and calcined. In the dispersion of the cation exchange resin, the cation exchange group may have, for example, a resin such as a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a phosphoric acid group or the like, and particularly a perfluorosulfonic acid having a sulfonic acid group and excellent chemical stability. Acid type cation exchange resin The dispersion is better. The "perfluorosulfonic acid type cation exchange resin" is considered to be not completely dissolved in a solvent, and a large colloid having a diameter of about 10 nm is formed in a solvent and aggregated.

The dispersion liquid formed as described above is applied onto the surface of the cathode base material 2a by, for example, spraying, a roller, a brush, a sponge, or the like, and dried by a solvent at room temperature for a predetermined period of time. At this time, the dispersion is kept in a state of being dropped from the nozzle and the chips, and the leveling can also be wetted by the expansion of the dispersion. Further, the dried coating-formed dispersion-electrode substrate was heated to 120 to 350 °C. The heating system may be a dryer, a simmering furnace, a high temperature heat gun, or a hot plate. The heating temperature must not only evaporate the solvent, but also cause the coacervate to be sintered. However, if it is too high, there is a possibility that the polymer may be deteriorated, so that it is preferably about 150 to 250 °C. It is considered that the aforementioned minute gap is formed at this time.

Further, the powder coating of the cation exchange resin may be carried out by a powder coating method, and then the heat treatment may be used to form a semi-molten and densely coated.

In the reinforcing material containing a cation exchange resin to prevent adhesion of an alkaline earth metal scale, if a fluororesin crosslinking agent, a fluororesin or an ion exchange resin filler is contained in a dispersion of a cation exchange resin in advance, after heat treatment The film containing the cation exchange resin to prevent the adhesion of the alkaline earth metal scale can be reinforced.

Further, in the film containing the cation exchange resin to prevent the adhesion of the alkaline earth metal scale, the film such as apatite, perovskite oxide and zeolite is contained. The cation exchange resin of the cation exchange ability ceramic fine particles is contained in the film, and the mechanical strength can be improved without hindering the movement of the cation in the film.

Further, a film containing a cation exchange resin to prevent adhesion of an alkaline earth metal scale may be disposed on both surfaces of the electrode substrate, and a bag-like covering structure may be formed by adhering the surrounding and, if necessary, the plurality of intermediate portions. Moreover, such a structure can also be manufactured by hot pressing. However, it is necessary to design a fine opening for discharging a gas such as hydrogen generated on the surface of the cathode. At this time, it is also possible to form a structure in which only the upper portion is open.

An example of a diaphragm electrolysis apparatus shown in Fig. 3 is a 1-series cathode chamber, a 2-series cathode, a 3-series anode chamber, a 4-series anode, an energization member of a 6-series cathode 2, an energization member of a 7-series anode 4, and a 9-series hydrophilic porous body. The porous separator, the anode substrate 4a of the anode 4 is a porous screen, and the surface of the cathode substrate 2a is coated with the anode catalyst 4b, and the cathode substrate 2a of the cathode 2 is the same as the anode substrate 4a, and a porous screen is used. It is substantially covered with a film 8 containing a cation exchange resin to prevent the adhesion of alkaline earth metal scale.

Fig. 4 shows an example of a three-slot type electrolysis apparatus, a 1-series cathode chamber, a 2-series cathode, a 3-series anode chamber, a 4-series anode, an energization member of a 6-series cathode 2, an energization member of a 7-series anode 4, and an 8 system-containing cation. The membrane for preventing the adhesion of the alkaline earth metal scale of the resin, the 10-series anion exchange membrane, the 11-series cation exchange membrane, and the 12-series intermediate chamber, and the anode substrate 4a of the anode 4 are made of a porous sieve and covered on the surface thereof. The anode catalyst 4b, the cathode substrate 2a of the cathode 2 and the anode The polar substrate 4a is similarly all made of a porous mesh, and is substantially entirely covered with a film 8 containing a cation exchange resin for preventing adhesion of an alkaline earth metal scale.

These electrolyzers generate various functional waters and ozone water.

The term "functional water" as used in the present invention means "in an aqueous solution obtained by manual processing to obtain reproducible useful functions, and the related processing and function can be clearly understood by a scientific basis, and those who want to be clear." There are various functional waters such as electrolyzed water and ozone water in the functional water system.

Furthermore, the definition and type of electrolyzed water are as follows according to the website of the Foundation Research and Development Research Foundation.

The electrolyzed water system is a general term for an aqueous solution obtained by performing electrolytic treatment using a weak direct current voltage such as tap water or rare salt water. Various materials can be manufactured according to different conditions of the device, electrolysis conditions, etc., and can be roughly classified into sterilizing electrolyzed water (such as strong acid electrolyzed water, slightly acidic electrolyzed water, etc.) used for sanitary management such as washing and disinfection according to the purpose of use. Alkaline electrolyzed water (alkaline ionized water) which has an obvious effect on the improvement of gastrointestinal symptoms if it is used as an aqueous solution of sodium hypochlorite, which is considered to be a dilution of sodium hypochlorite.

The "acidic electrolyzed water" refers to electrolyzed water having a pH of 6.5 or less, and is collectively referred to as "acidic electrolyzed water". It exhibits a wide range of strong bactericidal power against various pathogenic bacteria, such drug-resistant bacteria (MRSA, etc.), and is utilized in various fields such as medical, dental, food, or agriculture. The main bactericidal factor is hypochlorous acid produced by electrolysis. Therefore, in 2002, strongly acidic electrolyzed water and slightly acidic electrolyzed water were considered "there is no threat to human health damage". The name "hypochlorous acid water" is also given when it is designated as a food additive.

The "strongly acidic electrolyzed water" means that 0.1% or less of saline (NaCl) is electrolyzed in a double-slot type electrolytic cell in which the anode and the cathode are separated by a separator, and hypochlorous acid generated on the anode side is mainly generated. The electrolyzed water having a pH of 2.7 or less and having a pH of 2.7 or less is referred to as "strongly acidic electrolyzed water" (strongly acidic hypochlorous acid water). At the same time, the strongly alkaline (pH 11 to 11.5) electrolyzed water generated on the cathode side is referred to as "strong alkaline electrolyzed water".

The "slightly acidic electrolyzed water" refers to a single-channel electrolyzer in which the anode and the cathode are not partitioned by a separator, and electrolyzed with 2 to 6% hydrochloric acid water to form a pH of 5 to 6.5 and an effective salt of 10 The ~30 ppm hypochlorous acid aqueous solution has the characteristic that all of the produced water belongs to sterilizing water.

The term "alkaline ionized water" refers to a general term for a weakly alkaline (pH 9 to 10) drinking electrolyzed water produced by electrolysis of drinking water using a household electrolyzed water generator known as an "alkaline ion water purifier". In addition, the "electrolyzed water generator for household use" is referred to as a home medical device classified as "medical device generator for medical device 83" in the Japanese Pharmacy Act. The efficacy effect of the related alkali ionized water was subjected to rigorous comparative clinical trials, and the results confirmed the following performance effects that can be recognized as medical appliances. That is, it is effective for "chronic diarrhea, indigestion, abnormal fermentation in the stomach, acid production, and hyperacidity". Also, it has been found to improve the constipation. At present, according to the revision of the Japanese Pharmaceutical Affairs Law (2005), it has been revised to have "intestinal symptoms improvement effect".

In the present invention, the term "ozone water" means by means of pure water or tap water. The electrolysis unit of the present invention is subjected to electrolysis using the liquid to be treated, the waste water, the waste liquid, etc., to obtain an electrolysis product mainly containing ozone gas, and contains, in addition to the ozone gas, an OH radical, superoxide. Ozone-containing gas such as anion, oxygen peroxide, hydrogen peroxide, and other oxidizing substances. The ozone water acts as a main body of oxidation at a low pH (acidic), and the ozone gas decomposes at a high pH (alkaline), and at this time, it acts. Oxidation by the OH radical becomes the main component, and even if the total oxidation equivalent is the same, the oxidation becomes more powerful.

The present invention is applicable to an electrolysis device for performing such as hydrogen/oxygen production, ozone water production, alkali ion water production, acidic water production, slightly acidic water production, wastewater treatment, and the like.

Further, the operation mode is suitable for a method in which a catholyte containing an alkaline earth metal ion is stably flown, but a method of periodically replacing a non-refined catholyte containing an alkaline earth metal ion can also obtain an effect.

[Examples]

Next, the present invention will be more specifically described by way of examples, but the invention is not limited thereto.

[Example 1]

In the first embodiment, an SPE type electrolytic cell (SPE is a registered trademark of PERMELEC ELECTRODE Co., Ltd.) is used as the solid polymer electrolyte type electrolytic device of the double-slot type electrolytic device shown in Fig. 1. As the anode base material 4a and the cathode base material 2a, a sieve made of SUS304 having a porous metal mesh size of 30 mm × 30 mm was used (screen size: plate thickness: 1 mm, SW 3.5 mm, specific surface area: 1.1 m ² /m ² ). The cathode 2 is coated with a commercially available cation exchange resin 5% dispersion (trade name: Nafion DE520, a registered trademark of Nafion DuPont Co., Ltd.) in addition to the connection portion between the cathode and the current-carrying member 6, Calcination was carried out at 170 ° C to form a state in which the cathode 2 was substantially completely covered by the film 8 containing the cation exchange resin and preventing the adhesion of the alkaline earth metal scale. Further, Pt was applied to a screen of Ti having the same shape to form an anode 4. A cation exchange membrane 5 (trade name: Nafion 117, registered trademark of DuPont Co., Ltd.) is interposed between the anode 4 and the cathode 2, and 300 mL per minute is used in the anode chamber 3 and the cathode chamber 1 of the electrolysis apparatus. The tap water was circulated, and an electric current test was performed by supplying a current of 1.8 A. During the test, the voltage between the anode and cathode is regarded as the voltage of the electrolytic cell, and monitoring is performed at regular intervals. As a result, as shown in Fig. 5, in the first embodiment, it took 26 hours until the cell voltage reached 20 V, and it was apparent that the effect of suppressing the voltage rise was obtained by coating the cation exchange resin of the cathode.

In addition, compared with the second embodiment described in the following paragraph and the third embodiment, the voltage rise of the first embodiment is more rapid, and the applied current value is considered to be higher, and compared with the second embodiment, the anode is There is a poorly bonded cation exchange resin film coated with a cation exchange resin, and only hydroxides of alkaline earth metal ions are accumulated in the space between the anode and cathode, and alkaline earth metal ions are accumulated in the film. Caused by sake.

In addition, in the first embodiment, it is assumed that ordinary water for supplying oxygen and hydrogen is used. Electrolysis, using a Pt-coated anode and performing electrolysis at a lower current density, but by using a high current density electrolysis or by using a material such as a conductive diamond to generate a material having a high overvoltage as an anode, according to the following The reaction produces ozone water.

The generation of ozone is based on the following reaction formula: ozone generation reaction (anode): 3H ₂ O=O ₃ +6H ⁺ +6e ^-

E ⁰ = +1.51V

Oxygen generation reaction (anode): 2H ₂ O=O ₂ +4H ⁺ +4e ^-

E ⁰ = +1.23V

Hydrogen formation reaction (cathode): 2H ⁺ +2e ^- = H ₂

The above ozone generation reaction belongs to the competition reaction of the oxygen generation reaction in the lower stage, and oxygen having a lower potential is preferentially generated, so that the current efficiency is low. Further, from the viewpoint of suppressing the generation of oxygen, when an electrode having a high overvoltage such as lead oxide or a conductive diamond electrode or a platinum-coated electrode is used, electrolysis can be performed at a high potential by high current density electrolysis.

[Comparative Example 1]

The electrolysis apparatus having the same configuration as that of Example 1 was tested in comparison with the cathode system using a SUS304 screen which was coated with the coating 8 for preventing the adhesion of the alkaline earth metal scale containing the cation exchange resin, and was compared for comparison. example 1. In Comparative Example 1, SPE electrolysis was carried out by the presence of a cation exchange resin film. As a result, as shown in Fig. 5, in Comparative Example 1, the voltage rises immediately after the start of electrolysis, and reaches 20 V at about 8 hours. This is now It is shown that in the tap water electrolysis using a general electrolysis unit according to the present conditions, it is difficult to continue electrolysis for a long time.

[Embodiment 2]

In the second embodiment, the diaphragm electrolysis apparatus shown in Fig. 3 was used. Pt was applied to a Ti mesh having a size of 16 mm × 16 mm (mesh size: 1 mm, SW 3.5 mm, specific surface area 1.1 m ² /m ² ) to form a cathode 2 and an anode 4. Further, a substantially 5% dispersion of a commercially available cation exchange resin (trade name: Nafion DE520, registered trademark of DuPont Co., Ltd.) was applied to the entire surface of the cathode 2, and then calcination was carried out at 150 ° C to form a cation. The film 8 of the resin which prevents the adhesion of the alkaline earth metal scale is exchanged. The cathodes 2 and the anodes 4 are arranged side by side at intervals of about 1.5 mm, and are separated by a 20 mm × 20 mm hydrophilic porous separator 9 (so-called neutral membrane). These are placed in the central portion of the cathode chamber 1 and the anode chamber 3 of the diaphragm electrolysis apparatus.

In the anode chamber 3 and the cathode chamber 1 of the electrolysis apparatus, tap water was supplied at 12 mL per minute, and a current of 0.03 A was supplied, and an electrolysis test was performed at normal temperature. During the test period, the voltage between the cathode 2 and the anode 4 was regarded as the electrolysis cell voltage and monitored at intervals of 30 seconds.

As a result, as shown in Fig. 6, in the second embodiment, the temperature was always stabilized in the range of 20 to 26 V, and the suppression voltage obtained by the film 8 containing the cation exchange resin for preventing the adhesion of the alkaline earth metal scale formed by the cathode was apparent. Rise effect.

Further, the structure of the diaphragm electrolysis apparatus of the second embodiment is the same as that of the so-called alkali ion water purifier. The actual alkali ion water purifier, the substrate of the electrode The plate material is subjected to an effort of suppressing the mixing of the porous separator of the catholyte and the anolyte by passing a gap of about 1 mm between the cathode and the porous separator and rapidly passing through the catholyte. For reference, in the second embodiment, the average value of the pH of the catholyte at the outlet of the cathode chamber was measured at intervals of about 8 hours, which was 8.75, and the average value of the pH of Comparative Example 2 measured in the same manner was 8.98.

[Comparative Example 2]

In addition to the cathode 2, a Ti screen having a size of 16 mm × 16 mm, which is coated with a coating 8 for preventing the adhesion of an alkaline earth metal scale containing a cation exchange resin, is used (screen size: 1 mm, SW 3.5 mm, The cathode having a specific surface area of 1.1 m ² /m ² ) was applied to an electrolysis apparatus having the same configuration as that of Example 2 except that a cathode of Pt was applied, and Comparative Example 2 was used. As a result, in Comparative Example 2, as shown in Fig. 6, the cell voltage rises immediately after the start of electrolysis, and reaches 42 V at 100 hours.

[Example 3]

In the third embodiment, the three-slot type electrolytic apparatus shown in Fig. 4 was used. The anode 4 and the cathode 2 produced in the same manner as in the first embodiment were used, and the anion exchange membrane 10 (product name: TOSFLEX SF48, registered trademark of TOSOH Co., Ltd.) was used as the separator of the anode chamber 3 and the intermediate chamber 12, and was in the intermediate chamber. A cation exchange membrane 11 (product name: Nafion 117, registered trademark of DuPont Co., Ltd.) is used between the cathode chamber 1 and the cathode chamber 1 to constitute a three-slot type electrolytic apparatus. This configuration simulates a device in which alkaline salt water is produced from the anode chamber 3 by using the brine as a raw material, and so-called strongly acidic water including hypochlorous acid is produced from the anode chamber 3.

The intermediate chamber 12 of the electrolytic cell was circulated and supplied with a rare earth salt having a concentration of 30 g/L, and 500 mL of tap water per minute was supplied to the anode chamber 3 and the cathode chamber 1, respectively, and an electric current of 0.5 A was applied to conduct an electrolysis test. During the test, the voltage between the anode and cathode is regarded as the voltage of the electrolytic cell, and monitoring is performed at regular intervals.

As a result, as shown in Fig. 7, in Example 3, the voltage of the electrolytic cell was stopped at about 12 V, and the effects of the present invention were confirmed.

[Comparative Example 3]

The cathode 2 was subjected to an experiment using an electrolysis apparatus having the same configuration as that of Example 3, except that a sieve made of SUS304 coated with a film 8 for preventing alkali metal scale adhesion containing a cation exchange resin was used. Comparative Example 3. As a result, as shown in Fig. 7, the voltage of the electrolytic cell which was initially less than 7 V was raised to about 18 V after 480 hours.

(industrial availability)

The present invention is applicable to the following fields, but is not necessarily limited to these.

1. Wastewater / waste treatment 1) Processing device containing organic matter and high BOD/COD waste liquid

For example, Japanese Laid-Open Patent Publication No. 2006-281013 discloses a method of treating waste liquid containing organic matter by electrolysis. In this publication, it is assumed that the treatment of the sediment discharge water, factory wastewater, etc., which are contained in an alkaline earth metal ion such as Ca ion, is not clearly described in the specification, but it is known that when other special means are not used, A hydroxide or the like of the impurity ions is deposited on the cathode.

2) Decomposition of dissolved hardly decomposable substances

Japanese Laid-Open Patent Publication No. 2003-126860 proposes a method of removing a hardly decomposable substance such as an aromatic compound, a PCB, or a dioxin by electrolysis. However, since the waste liquid containing dioxin and the like is in the raw water stage, it is a non-refined water such as ground water or drinking water from the viewpoint of general availability/economicality, and therefore contains an alkaline earth metal element such as Ca ion. Impurities, such hydroxides and the like form precipitates and deposit on the cathode, so that it is difficult to continue the operation for a long period of time, and it is necessary to perform maintenance such as acid washing on a regular basis. At this time, according to the electrolytic unit of the present invention, the cathode deposit can be suppressed, and the operation can be continuously performed for a long period of time, and the maintenance cost can be greatly reduced.

2. Electrolyzed water production

There are various proposals for a method and apparatus for producing so-called electrolyzed water such as alkali ion water by electrolysis using non-refined water such as tap water as a raw material. These devices generally have problems of depositing hydroxide or the like on the cathode. For example, Japanese Patent Laid-Open Publication No. 2002-316155 discloses a means for dissolving and removing scale deposits on the cathode. According to the present invention, the deposition of hydroxide or the like can be reduced.

3. Ozone water production

A cathode of an ozone water generating device which is used as an anode and has a cation exchange membrane interposed therebetween, such as a conductive diamond, generally has a non-refined water such as tap water, and thus a hydroxide or the like appears on the cathode. The problem of precipitation is, but according to the present invention, the amount of precipitation can be greatly reduced.

1‧‧‧Cathode chamber

2‧‧‧ cathode

2a‧‧‧Cathode substrate

3‧‧‧Anode chamber

4‧‧‧Anode

4a‧‧‧Anode substrate

4b‧‧‧Anode Catalyst

5‧‧‧Cation exchange membrane

6‧‧‧Electrical components of cathode 2

7‧‧‧Electrical components of the anode 4

8‧‧‧film containing cation exchange resin to prevent the adhesion of alkaline earth metal scale

9‧‧‧Hydrophilic porous membrane

10‧‧‧ anion exchange membrane

11‧‧‧Cation exchange membrane

12‧‧‧Intermediate room

Fig. 1 is a cross-sectional view showing an SPE (registered trademark) type electrolysis apparatus which is an example of a double-channel type electrolytic apparatus according to an embodiment of the present invention.

Fig. 2 (a) is a cross-sectional view showing an example of an anode used in the present invention.

Fig. 2 (b) is a cross-sectional view showing an example of a cathode used in the present invention.

Fig. 3 is a cross-sectional view showing a diaphragm electrolysis apparatus according to another embodiment of the present invention.

Fig. 4 is a cross-sectional view showing an example of a three-channel type electrolytic apparatus according to still another embodiment of the present invention.

Fig. 5 is a graph showing the relationship between the electrolysis time and the cell voltage as a result of Example 1 of the present invention and Comparative Example 1.

Fig. 6 is a graph showing the relationship between the electrolysis time and the cell voltage as a result of Example 2 of the present invention and Comparative Example 2.

Fig. 7 is a graph showing the relationship between the electrolysis time and the cell voltage as a result of Example 3 of the present invention and Comparative Example 3.

1‧‧‧Cathode chamber

2‧‧‧ cathode

3‧‧‧Anode chamber

4‧‧‧Anode

5‧‧‧Cation exchange membrane

6‧‧‧Electrical components of cathode 2

7‧‧‧Electrical components of the anode 4

Claims (12)

An electrolysis device comprising: a separator, an anode chamber partitioned by the diaphragm, a cathode chamber partitioned by the diaphragm, an anode provided in the anode chamber, and a cathode provided in the cathode chamber, and the cathode a chamber for supplying a raw material water containing an alkaline earth metal ion; wherein the cathode is substantially entirely covered by a film containing a cation exchange resin for preventing adhesion of an alkaline earth metal scale, and preventing the occurrence of the alkali on the surface of the cathode Precipitation of hydroxides of the earth metal. The electrolysis device according to claim 1, wherein the separator is a diaphragm-type electrolysis device using a porous separator. The electrolysis device according to claim 1, wherein the separator is a cation exchange membrane electrolysis device using a cation exchange membrane. The electrolysis device according to claim 3, wherein the anode and the cathode are closely adhered to both surfaces of the cation exchange membrane to constitute a solid polymer electrolyte type electrolysis device. The electrolysis device according to claim 1, wherein the separator that isolates the anode chamber from the cathode chamber is provided with a cation exchange membrane and an anion exchange membrane between the anode chamber and the cathode chamber, and the cation is An intermediate chamber is formed between the exchange membrane and the anion exchange membrane to form a three-slot type electrolysis device. The electrolysis device of claim 1, wherein the anode catalyst of the anode is made of conductive diamond, lead dioxide, noble metal and noble metal oxygen. Compound. The electrolysis device according to claim 1, wherein the anode and the cathode are provided with an energization member. The electrolysis device according to the first aspect of the invention, wherein the filler comprising a cation exchange resin for preventing adhesion of an alkaline earth metal scale is mixed with a filler composed of a fiber or a powder formed of an inorganic/organic material. Used as a reinforcing agent for the film. The electrolysis apparatus according to claim 1, wherein the ceramic microparticles having the cation exchange energy are mixed in the film containing the cation exchange resin and preventing the adhesion of the alkaline earth metal scale. The electrolysis device according to claim 9, wherein the ceramic microparticles having the cation exchange ability are at least one ceramic fine particle selected from the group consisting of apatite, perovskite oxide and zeolite. The electrolysis device according to claim 1, wherein the cathode base material of the cathode is a plate material, a porous metal, a fibrous metal molded body, a mesh, or an open-hole punched metal. An electrolysis method is carried out by electrolyzing a raw material water containing an alkaline earth metal ion using the electrolysis apparatus according to any one of claims 1 to 11.