DE3226347A1 - ELECTROLYSIS DEVICE AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

HOFFMANN · EITLE & PARTNER

PATENT LAWYERS

& R. ING. E. HOFFMANN (1930-1976). DIPL.-ING. W. EITLE DR.RER. NAT. K.HOFFMAN N DIPL.-ί NG. W. LEHN

DIPL.-ING. K, FDCHSLE. DR. RER. NAT. B. HANSEN ARABELLA STREET 4. D-8000 MD NCHEN 81. TELEPHONE (089) »11087 · TELEX 05-29619 (PATHE)

PERMELEC ELECTRODE LTD ♦, KANAGAWA / JAPAN

Electrolysis device and method for producing it * position

The invention relates to an electrolysis device using an ion exchange membrane and a process for its manufacture *

In particular, the invention relates to an electrolyzer having an ion exchange membrane as a solid polymeric electrolyte diaphragm in which the cathode and / or anode are permeable from a gas-liquid porous plate tightly to an ion exchange membrane by means of a powdery ion exchange resin is present. The invention also relates to a

Method of manufacturing the electrolysis device »

Economic considerations related to energy and energy sources, e.g. reducing the Power consumption or the downsizing of apparatus sizes, etc., due to the rapid increase in Energy costs are currently in the foreground.

In the electrolysis of aqueous solutions of sodium chloride, etc., one has in the past Cathode and an anode by means of an interposed one Diaphragms kept at a distance. It has already been proposed to improve the cathode and anode close to the cation exchange membrane, because this reduces the electrical resistance due to the gas generation is decreased and the electrolytic voltage decreases (see JP-OS 47 877/79 and 60 295/79).

Furthermore, there are various types of so-called plague polymer electrolyte (SPE) electrolysis processes known. Thus, in Japanese Patent Publication 45 557/76 (corresponding to US Pat. No. 3,489,670) and JP-OS 78 788/77 (corresponding to US Pat. No. 4,039,409) describes the electrolysis of water, in JP-OS 52 297/78 the electrolysis of Glauber's salt, in JP-OSes 95 996/79 and 97 581/79 the hydrolysis of hydrochloric acid and in Japanese Patent Laid-Open Nos. 102 278/78, 93 690/79, 107 493/79, 112 398/79, 115 982/80 and 131 187/80, hydrolysis described by sodium chloride. .

For electrolysis devices for the SPE process

an ion exchange membrane is used as the electrolyte diaphragm and layered cathode and anode catalyst materials are placed on both sides of the Diaphragm held directly bound, whereby the electrolysis is carried out * This is electrical Electricity is supplied by bringing a supply in contact with the electrode catalyst layer. A typical property here is that the distance between the electrodes depends on the thickness of the diaphragm is reduced and that theoretically the electrolysis solution between the electrodes does not exist is. As a result, it is possible to reduce the size of the apparatus to a considerable extent. Since there is still a loss of electrical resistance due to the electrolytic solution between the Electrodes and the generation of bubbles can be neglected, one can at least use the corresponding one Reduce the value of the electrolysis voltage. As a result, the SPE process is an excellent electrolysis system for energy saving.

In the known, closely spaced electrode processes and SPE method, however, gradually finds bending or wrinkling on the ion exchange membrane with continued electrolysis, and as a result, a gas such as hydrogen or Chlorine, etc. due to the separation or the unevenness the ion exchange membrane and gives a bad one Contact of the power supply with the electrode catalyst layer or an uneven distribution of the electric current on the electrolyte surface. It

as a result, there arises a problem that the electrolytic voltage suddenly increases.

In JP-OS 138 088/80, 139 842/80 and 141 580/80 methods for solving these problems are proposed, by inserting a metal wire or a mesh or a porous plate as a reinforcement part into the inner part of the ion exchange membrane and a polytetrafluoroethylene dispersion used as an adhesive.

The introduction of a reinforcement part in the thin However, ion exchange membrane is problematic in terms of its manufacture and properties. In addition, since the adhesion of the electrode to the ion exchange membrane is still insufficient, there is a possibility of a separation between the two during prolonged electrolysis occurs and thereby the resistance caused by the adhesive increases.

The present invention solves the aforementioned problems.

An object of the invention is to show an electrolysis device using an ion exchange membrane, in which the adhesion between the ion exchange membrane and the cathode is excellent and can be operated in a stable manner for a long period of time without deforming the ion exchange membrane enters. The object of the invention is also to provide a method for producing the electrolysis device to show.

One embodiment of the invention relates to a Electrolysis device consisting of a cathode and an anode on both sides of an ion exchange membrane, where at least one of ^ both (the cathode or the anode) consists of a gas-liquid-permeable porous plate electrode> wherein the porous plate electrode is closely adhered to the ion exchange membrane , using a powdery ion exchange resin. In a second embodiment, the invention relates to a method of production such an electrolyzer.

The invention is based on the discovery that at the manufacture of an electrolytic device by attaching a porous plate electrode to an ion exchange membrane attached according to Japanese Patent Application 169 406/79 or JP-OS 131 187/80 and 138 o88 / 80, the ion exchange membrane is firmly bound to the electrode when used as a binder a powdery ion exchange resin is used for the ion exchange membrane to the electrode.

According to the invention, the ion exchange membrane adheres closely and fixed to the porous plate electrode, and thereby the dimensional stability is effected. Consequently there is no separation of the ion exchange membrane, even if the electrolysis is used carries out for a long time. One of the most notable effects is that you can bend it or creasing can be avoided without using any of the aforementioned reinforcement parts and

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one can operate in a stable manner with a low operating voltage for long periods of time.

The ion exchange resin used as a binder is similar to the resin used for the ion exchange membrane and has properties such that it can achieve the Properties of the ion exchange membrane as an electrolyte are not deteriorated. It also has the advantage that it increases the electrical resistance to a lesser extent.

The ion exchange membrane according to the invention is not limited and it is possible to use different types of ion exchange membranes alone or in combination, to be used depending on the type of electrolysis reaction .

Fluorine-containing solutions are preferred for the electrolysis of salt solutions Cation exchange membrane with ion exchange groups, such as carboxylic acid groups, sulfonic acid groups, phosphoric acid groups or phenolic Hydroxyl groups, etc., as described in the aforementioned Japanese Patent Laid-Open Nos. 131 187/80 and 138 088/80. Other suitable ion exchange membranes according to the invention can be used are disclosed in U.S. Patents 3,134,697, 3,297,482, 3,341,366, 3,432,353, 3,442,825; 3,489,670; and 4,039,409, the disclosures of which are hereby incorporated.

The electrode used in the present invention is a gas-liquid permeable porous plate,

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so that they adhere closely to the ion exchange membrane can. Preferably, both the cathode and the anode closely adhere to the ion exchange medium, but only need either the cathode or the Adhere the anode closely. The porous plate electrode can have various shapes * For example, can it as a network, as a fabric, as a grid, as a perforated plate, made of sintered porous material, made of spray-coated tem porous material and porous materials obtained by leaching a part out of it, exist. Such electrodes can be used as they are or as an electrode substrate, which is then provided with a electrode active substance is coated, can be used. It is further preferred that the porous Plate electrode has a porosity of about 10 to 99% and an opening size of about 1 (im to 5 mm, preferably 100 (am to 1 mm to the passage of the Electrolyte solution and the removal of the generated gas to facilitate, so that no deformation of the ion exchange membrane entry. Suitable porous plate electrodes can be made using various well known Materials and various known methods depending on the electrolysis reaction for which the electrodes are determined, can be prepared and the methods in the aforementioned JP-OS 131 187/80 and 169 406/79 (corresponding to US patent application serial no. 217 608 of December 18, 1980) also apply.

For example, it is the case with the electrolysis of a saline solution possible as electrodes porous plates made of iron, nickel, titanium, zirconium, niobium or alloys containing these

Containing metals as the main component, for example Ti-Ta, Ti-Ta-Nb, etc., alloys, platinum metals such as Pt, Ru, Ir, Rh or Pd, or oxides thereof such as RuO ₂ , IrO ₂ / etc., or others Metals or metal compounds such as WO ₃ , MoO ₂ / etc., and carbon or combinations thereof or porous plates made of iron, nickel or titanium, etc. which are coated with a cathode active material using known means, for example by thermal decomposition processes, or those prepared by a powder sintering method or an electric plating method or a spray coating method are to be used. For example, flame plasma spraying, according to JP-OSes 40 676/73 and 46 581/76, can be used.

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It is also possible to use porous plates made of platinum metals, such as platinum, ruthenium, palladium, iridium, rhodium, etc., or oxides thereof, such as RuO ₂ , PdO, IrO ₂ , Rh ₂ O ₃ , etc., or other metals, as anodes such as titanium, tantalum, tin or cobalt, etc., or oxides thereof such as TiO ₂ , Ta ₂ O ₅ , SnO ₂ , etc., or combinations thereof such as RuO ₂ -TiO ₂ , RuO ₃ -IrO ₂ -Ta ₂ O ₅ , RuO ₂ -SnO ₂ -TiO ₂ , Pt-SnO ₂ , etc ,, or porous plates made of titanium, tantalum, zirconium or electrically conductive oxides thereof, such as. TiO ₂ where 0 <x <0.5 coated with an anode active substance using known means, for example, by thermal decomposition method or sintering method or plating method or by spray coating method, etc. to apply. Such anodes and processes are described in US Pat. Nos. 3 711 385, 3 632 498, etc.

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The formed porous plate electrode is closely adhered by using the aforementioned ion exchange membrane a powdery ion exchange resin.

Examples of powdered ion exchange resin ^ that Can be used here are known resins having sulfonic acid groups, sulfonamide groups or carboxylic acid groups , etc., as ion exchange groups and the resins used in the manufacture of the membranes ih the previously mentioned publications can be used in powder form. It is preferred to use the same ion exchange resin as in the ion exchange membrane with an ion exchange capacity from about 0.1 to 3 milliequivalents / g of the dry resin to ensure the tight adhesion of the ion exchange membrane to improve the electrode without • impairing the electrolytic capacity of the same. For example, if you use Nafion no. 120 or 110 (Nafion is a trademark of E.I. du Pont de Nemours Co., Inc.) as the ion exchange membrane, then a powder of the same resin is preferably used as described above or an ion exchange resin available as a powder such as Nafion No. 501 or No. 511 used. Although the particle size of the powdery ion exchange resin can be adjusted appropriately however, selectf is the average particle size preferably equal to or smaller than the average opening size of the porous plate electrode. In general, ion exchange resins in powder form having an average particle size can be used use from about 0.5 to 1 mm. Will the ion exchange resin powder such a particle size as a binder

used, then it easily penetrates the openings of the porous plate electrode during a heat treatment under pressure, so that it is impregnated with it or fused therein, and thereby the ion exchange membrane becomes firm and close to the porous plate electrode bound.

Various methods are possible for bonding the porous plate electrode to the ion exchange membrane using the powdery ion exchange resin. In the simplest method, a powder of the ion exchange resin is placed on the surface of the porous plate electrode or the ion exchange membrane in a uniform thickness and both are then pressed simultaneously with heating with the surfaces to be connected, the electrode side fusing with the ion exchange resin. Preferably, the heating temperature should be about 80-380 ⁰ C and the bonding pressure are about 10 to 1000 bar.

The heat treatment under pressure can be carried out in air or, if desired, in an inert atmosphere such as Nitrogen or argon, etc., can be carried out. It is still possible to use a procedure for which one beforehand the surface to be connected to the porous Plate electrode impregnated with the powdery ion exchange resin by mechanical introduction under pressure or by applying a liquid dispersion of the powdery ion exchange resin and then, if desired when heated, it fuses to form a binder layer on the surface of the porous plate electrode, whereupon the ionic

The exchange membrane binds to it under pressure and heat. Furthermore, it is possible to use a method in which a powdery ion exchange har as Applies binder to one or both sides of the ion exchange membrane during its manufacture and then the porous plate electrode with. the ion exchange membrane under pressure and heat connects. The latter method has the advantage that the adhesion of the ion exchange resin to the ion exchange membrane and the bonding of the Ion exchange resin can be carried out with the porous plate electrode under each optimal condition can.

One uses a porous plate electrode, which with an electrode-active substance as electrolytic • conductive porous electrode substrate is coated, it is possible to use a method in which one using the ion exchange membrane to the electrolytically conductive porous electrode substrate of the powdery ion exchange resin binds and using the aforementioned method and then the electrode substance can be coated with an electrode-active substance * With this one The method of coating with the electrode active substance must be carried out under such conditions in which the ion exchange membrane does not break, e.g. by spraying, electrical Plating process or vacuum application process / etc. * The process according to the invention can also be used Do not only apply if you have a porous inactive

Layer between the ion exchange membrane and the electrode according to the Japanese patent application 169 406/79 and JP-OS 75 583/81, but also in the manufacture of other analog electrolysis cells.

The invention is described on the basis of the following examples, which are by no means to be interpreted as limiting.
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example 1

To a 20 (grating pitch: about 0.7 mm) mesh nickel net with a wire diameter of 0.5 now and an area of about 50 cm ^2, a nickel powder having an average particle size of 100 μπι by 10 minutes of sintering at 900 ⁰ C in an H ₂ atmosphere, a porous plate cathode was obtained on which a porous layer about 200 μm thick and with a porosity of about 80% was formed on the side on which an ion exchange membrane was applied.

A commercially available ion exchange resin was also used (Ion exchange capacity: about 0.8 milliequivalent / 1 g dry resin) (Nafion No. 501) on one average particle size of 70 μm pulverized. The above-mentioned porous cathode layer was sufficiently impregnated with the formed powder and

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furthermore a small amount, 2.B. applied about 5 g / m ^{2 of} the same powder. An ion exchange membrane made of Nafion no. 120 was applied to the processed layer and the adhesion of the ion exchange membrane to the porous nickel electrode was carried out at 250 ⁰ C and a pressure of 10 bar. Using an expandable grid 2 mm thick as an anode, an electrolytic cell was constructed by placing the anode at a distance of 3 mm from the ion exchange membrane. For comparison purposes, an electrolytic cell was used in which the above-mentioned cathode without an ion exchange membrane attached thereto was placed at a distance of 1.5 mm. In the case of an electrolysis at 40 ⁰ C of a 10% aqueous NaOH solution, which is in the cathode chamber or.

was introduced into the anode chamber, the elec-. trolysis voltage where the cathode is bound to the ion exchange membrane according to the present invention was about 200 mV less than the cathode which was not bound to the ion exchange membrane. One Separation of the ion exchange membrane from the cathode was also achieved after 1,000 hours of electrolysis not detected, so the operation is continuous stable was possible.

Example 2

Titanium powder was placed on a rolled titanium mesh with a thickness of 0.1 mm and an aperture ratio of 60%

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having an average particle size of about 50 μΐη applied as a uniform porous layer and the layer was at 1100 ⁰ C for 20 minutes

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sintered in vacuo (10 Torr), forming a porous plate with a thickness of about 50 μm and a porosity of about 80%. This porous plate was coated with a mixed oxide of Ru and Ti in a metal ratio of 60:40% by weight using a conventional thermal decomposition method to form a porous plate anode.

Subsequently, the surface of the aforementioned porous anode was impregnated with pulverized Nafion No. 500 (ion exchange capacity: about 0.8 milliequivalent / 1 g dry resin) and having an average particle size of 20 μm or less, and a Nafion No. 315 ion exchange membrane was attached the surface treated in this way is ^{bound at 250 °} C. by pressing on with a pressure of 20 bar.

Platinum black (specific surface area 30 m ² / g) and a polytetrafluoroethylene dispersion were mixed in a weight ratio of 100:30. The mixture was applied to the other surface of the aforementioned ion exchange membrane and formed a cathode layer, and using this, an electrolytic cell was constructed,

For comparison purposes, an electrolytic cell was built in the same way, but with the anode directly

was bonded to the ion exchange membrane without using an ion exchange powder.

At an electrolysis at 80 ^Q C _f wherein a 4N aqueous solution of NaCl was added to the anode chamber and a 20% NaOH solution to the cathode chamber, the operation was stable at a device according to the invention at an average electrolytic voltage of 3 , 3 V for 1,000 hours and more, with no separation of the anode from the ion exchange membrane being observed. In the comparative electrolysis, the anode separated from the ion exchange membrane and the electrolysis voltage increased rapidly to 1.0 V or more 15 minutes after the start of the electrolysis.

Example 3

A porous nickel plate about 1 mm thick (Cermet No. 5, manufactured by Sumitomo Electric Ind. Ltd.) was used to prepare a porous plate with rolled to a thickness of 0.3 mm and a porosity of 9.0%. The plate was covered with platinum to a thickness of about 1 μΐη coated by thermal decomposition / with the formation of a cathode. Then, the surface thereof was coated with an ion exchange resin powder (Nafion No. 501) with an average particle size of 50 μm and a thickness of about 0.2 mm

impregnated. An aluminum foil was placed on the porous cathode formed and the arrangement was ^{pressed at a temperature of 300 °} C. at a pressure of 200 bar in a nitrogen atmosphere. After removing the aluminum foil, it was found that a uniform layer of the ion exchange resin was formed in close adherence to one side of the porous nickel cathode plate.

Then, on the formed membrane layer an ion-exchange membrane (Nafion no. 315) by pressing at 250 ⁰ C and glued 150 bar.

A Ti mesh coated with a mixed oxide of RuO ₂ : TiO ₂ in a weight ratio of 1: 1 was used as the anode, which was at a distance of 2 mm from the ion exchange membrane. In electrolysis with an electrolytic cell constructed in this way under the same conditions as in Example 2, the operation could be stably operated with a

Electrolysis voltage of about 3.3 V can be carried out for 1,000 hours or more with no separation of the porous nickel electrode from the ion exchange membrane. 25th

Claims (10)

HOFFMANN · EITLE <& PARTNER PATENTANWÄLTE DR. ING. E. HOFFMANN (1930-197 <S). Dl PL.-ING. W. EITLE · DR. RE R. NAT. K. HOFFMANN - Dl PL.-I N G. W. LEHN DIPL.-I NG. K. FOCHSLE DR. R E R. N Af. B. H AN S E N ARABELLASTRASSE A ■ D-8000 MO NCH EN 81. TELEPHONE (089) 911087 · TELEX 05-2901? (PATHE) 37 175 o / wa - 1 - PERMELEC ELECTRODE LTD., KANAGAWA / JAPAN Electrolysis device and process for its manufacture. PATENT CLAIMS 1. Electrolysis device with a cathode and an anode and an ion exchange membrane located therebetween, characterized in that the cathode and / or Anode a gas-liquid permeable porous Plate electrode is made tight using a powdery ion exchange resin adhered to the ion exchange membrane 2. Electrolysis device according to claim 1, characterized characterized that the ions--, exchange membrane and the ion exchange membrane powder each have an ion exchange capacity of about 0.1 to 3 milli-equivalents / g dry resin. 3. Electrolysis device according to claim 1, characterized in that the Apparatus includes a porous plate cathode closely bonded to the ion exchange membrane using a powdered ion exchange resin.
10 4. Electrolysis device according to claims 1 or 3, characterized in that the cathode is a porous plate made by (1) sintering a nickel powder or (2) applying a nickel powder to a porous nickel material by sintering. 5. Electrolysis device according to claim 1 or 3, characterized in that the cathode is a porous plate that is manufactured was made by (1) plating a porous nickel material with a platinum metal or (2) a sintered nickel powder product with a platinum metal. 6. Electrolysis device according to claim 4, characterized characterized in that the cathode is a porous plate made by Plating (1) a porous nickel material with a platinum metal, or (2) a sintered one Nickel powder product with a platinum metal. 7. Electrolysis device according to claim 1, characterized in that the device is a porous plate anode / to which an ion exchange membrane is closely adhered using a powdery ion exchange resin. 8. Electrolysis apparatus according to claims 1 or 7, characterized in t that the anode a porous plate is produced is further coated by sintering of titanium powder or by applying a titanium powder on a porous titanium material by sintering, and wherein the porous plate with a Metalloxidelektrodenkatalysator. 9. A method for manufacturing an electrolytic device having a cathode or an anode and a intermediate ion exchange membrane, thereby characterized in that one has a gas-liquid permeable porous plate electrode as at least one of the cathode and the anode and the porous plate electrode to the ion exchange membrane using a powdery ion exchange resin under pressure and heat adheres. 10. The method according to claim 9, characterized in that there is an ion exchange membrane using an electrolytically conductive porous material as the electrode substrate of the powdery ion exchange resin in the Heat adheres by pressure and the electrode substrate with a gas-liquid permeable Electrode-active material coated. . '■' .. ' 11, the method according to claim 9, characterized in that g e k e η η draws that one has a powdery ion exchange resin on at least one side of the Applying ion exchange membrane during the formation of the ion exchange membrane.