LU86876A1 - SEPARATOR FILM FOR A MODERATELY TRITRIATED ACIDIC WATER ELECTROLYSER AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

- 1/2192 LU

Γ ...... GRAND-DUCHY OF LUXEMBOURG

; Brief! N1 'v ...... **. *, _. Σ'Ρ-Κί-ε. \ Ion> -. Cür the Minister! i r ·· i c, / 'f -; % of A 2i. VS ·. Δ ü i X ....... JssäsäL, Economy and Movennes Classes I r · -. Intellectual Property Service I Title of book .......................................... .............. J /,

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Patent Application

& / · ............................................... .................................................. ............ ................. ___________________________________ ________________________________________________ (U

I. Request ........................ European Energy Community ..... atomicrue (EURATOM) ______ (21 L-2920 Luxembourg, Plateau du Kirchberg____________________________________________________ ............................................... .................................................. .................................................. .................................................. ................... {3 "deposit (s) this ....................... .. £ .... § ...... I4. & I43S7 --------------------------------- -------------------------------------- t 4.1 at AS .üV hours, at the Ministry of 'economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for an invention concerning: ...................... .................................................. .................................................. .................................................. ...............- (5) .............. "Film ..... slpsis-teur .poKrjiœ..jélec.trolys .draw ..... from ..... water ... acid _ _______________________________________ moderately tritriated and process for its manufacture ".................................

2. the description in French language ........................... of the invention in triplicate; 3 .................................. “.............. .................. drawing boards, in triplicate; e, enQf 4. receipt of the fees paid to the Luxembourg Registration Office on .........?. P ™ * l ~. * __: _______: 5. the delegation of power, dated _______________________ rr .............................. .................... on __________ — ___: _________________: 6. the successor document (authorization); declaring) assuming responsibility for this declaration, that F (es) inventor (s) is (are): (6)

Luigi GIUFFRE, Via Passo di FargoricLa6a ...... Milano, Italy_________________________

Giancarlo PIERIRI, ..... Via Campigli 911 ...... Vapes.e., ...... Italy .______________________________ ........ Giovanni MODI CA, Via AroMmede 41 “Milano. Italy__________________________________________ llzio IHÏPESTÎ'j Via le lïruzzi_ 1, Milano, Italy __ __________

Silvia MAFFI, Via Mossotti 2, Milano, Italy ...................................

.................................................. .................................................. ............................ dgffô'fëfrfsipÊîn ·?) _____________________________________________________________________ on (9) ........... .................................................. .................., ..... r ......................... .............................._................... .................................................. ...........................

under N ° (10) ........................................... ....................... = .......................... ...................____________________________________________... J_______ on behalf of (11) .................... ...........................................__ rr ...... .................................................. .................................................. .............: _______________________________________ élitfélisent) domicile for him (her) and, if designated, for his representative, in Luxembourg__________________________ ..C ° SManté ..... European ..... of ...... energy ... atomic, ..... lr-2920. .Luxembourg _____ (12) requests (s) the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, with postponement of this grant to .............. .................................................. .... 1.2 ___________________________________ months. (13)

The depositor / xncsæxiHinQC ..............._.............................. .................................................. .................................................. ..................................... ............. ...... (14)

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H. KROUZ, Power Foundry Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and Middle Classes, ImelteemeftràsLuxembourg Property Service, dated:, _ * Z "" e 1 C \ 1 3 HAÏ18S? / y-— f * '' i

If f / JT; ·;, ν · V \ pr. the Mimster of Economy and Average Qasses, at .......... hours | J / ¾¾¾¾ *; | p / ïtC y î \ r \ sëi The head of the Intellectuality Department,

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A 68007_Xfo _; _ J / __ EXPLANATIONS RELATING TO FORKMSôaéaEtlÉPôf: '/ (1) if applicable "Request for certificate of addiiiûû to the pnnapal patent, to the main patent application No .......... .do —........ enter! "last name. first name. prey" "".

address of the applicant, where the latter is; ur particular or corporate name. legal form, address of head office, when the applicant is a mjrais-f ?, msont person - 1 - Λ SEPARATOR FILM FOR AN ELECTROLYSER OF '

MODERATELY SORTED ACID WATER AND PROCESS FOR ITS MANUFACTURE

The invention relates to a separator film for an electrolyser of medium tritiated acid water and to a process for manufacturing such a film.

For a separator applicable to the acid electrolysis of heavy water and tritiated water, above all, chemical stability with respect to acid solutions and with respect to beta radiation is required. In addition, this separator must be easily wettable. This last characteristic is necessary to avoid the formation of gas bubbles in the separator, which would have the effect of reducing the tension and mixing the gases.

Isotopic separation of hydrogen by electrolysis is based on the difference in potential discharge at the cathode. In order to obtain purely cathodic gases, it is necessary to avoid any mixing with the anodic gases constituted by oxygen. Known separators meet this requirement by using different materials. As-best separators, which are generally used in the alkaline electrolysis of natural water up to a temperature of 80 ° C, are attacked by tritiated water. The isotopic exchange between hydrogen and tritium takes place in chains of magnesium hydrate and polysilicate, which constitute the basic polymer structure of this material. The exchanged tritium breaks down "in situ" in the structure of asbestos, emitting beta radiation and transforming into gas. This action, which takes place in practically all places in the fibrous structure, causes the rapid destruction of the 'asbestos.

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When researching other materials for the separator film, we also studied inorganic polymerized materials. These materials exhibit very high chemical inactivity and good wettability, even under conditions of acid electrolysis. However, these materials can only rarely be prepared in the form of fibers or microporous films, since their state of aggregation is generally pulverulent. Among the polymerized organic materials, there are only very few which withstand severe conditions existing in an acid electrolytic cell. Among these materials there are some such as polytetrafluoroethylene, polyphenylsulfide, polyphenylenes, which are sufficiently chemically resistant, but their wettability is not sufficient for the intended application.

Next, we studied polysulphone, which can be produced in the form of fibers or a microporous film. As in the previous case, gas bubbles are observed inside the separator. Separators were then prepared for alkaline electrolysis by mixing polyantimonic acid with polysulphone. However, these separators have not risen as efficient, because the polyantimonic acid dissolves in the alkaline environment, leaving the matrix of the organic polymer, which is not very wettable and fills with gas bubbles.

The object of the invention is to propose a new material for a composite separator comprising an organic binder and an inorganic ion exchanger. Such a separator must be resistant to tritiated water and must have good wettability.

This object is achieved according to the invention by the fact that the film contains a binder consisting of an aromatic polymer such as a polysulphone, a polyethersulphone, a polyphenylene sulphide or a polytetrafluorethylene in an amount of 30 to 99%, preferably i - 3 - rence from 45 to 96% by weight, as well as between 70 and 1% by weight, preferably between 55 and 4% by weight, of polyantimonic acid.

Such a separating film can be manufactured according to a process as specified in claims 2 to 4.

The ion exchanger belongs to the family of poly-antimonic acids having the general formula Sb2O3.nH2 <0. These acids can be obtained by hydrolysis of SbCl ^. The presence of these acids guarantees good wettability and a great capacity for repelling gas bubbles. Another important point in favor of polyantimonic acid is that it is capable of exchanging hydrogen ions with the electrolyte.

The separators according to the invention are in the form of membranes impermeable to the electrolyte, or else as porous membranes, which are permeable to the electrolyte. The composite separators according to the invention are very resistant to mechanical abrasion and can be manufactured with great stability of their structure, which makes it possible to obtain very thin separators. It is therefore possible to safely maintain predetermined and small distances between anode and cathode, and to increase the faradaic efficiency.

. As an unexpected result, it has been found that by mixing an organic polymer of the aromatic type with an inorganic polymer of polyantimonic acid; a separator is obtained which has a high resistance to the acid environment and to mechanical attack and good wettability in the presence of heavy and tritiated water. In addition, the separator according to the invention makes it possible to recover very pure cathode gases (greater than 99.99%).

By modifying the quantity of polyantimonic acid present in the structure and by modifying its method of preparation, separators can be produced which are suitable for very diverse applications. It has also been found that by mixing 'ί - 4 -, / c with the composite materials during the preparation phase, a polymeric compound such as polyethylene glycol, polypropylene glycol, cellulose ethers and esters, polymaleic anhydride, and in general any polymer or compound which dissolves easily in a solvent. A porous structure of the composite materials is obtained, after treatment in this solvent, the porosity of this structure depending on the rate of soluble polymeric compound.

The invention will be described below using a few examples.

Example 1

A solution containing SbCl 4 and polysulphone (sold by Union Carbide under the name Udel 3500) is prepared in a 1: 3 molar ratio in 10 ml of N-methylpyrrolidone. The solution is stirred at room temperature for 6 hours, and then it is poured onto a glass support and distributed at constant thickness using a metal blade. The glass support with the solution layer is immersed in room temperature water. The migration of the solvent (N-methylpyrrolidone) to water is observed and a simultaneous formation of the membrane.

At the same time, antimony chloride is hydrolyzed and turns into polyantimonic acid.

The membrane spontaneously detaches from the support and is put in deionized water for 24 hours. During hydrolysis, part of the antimony chloride passes into the water, which explains why the content of antimony chloride in the film is no longer identical to that in the initial mixture.

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This membrane has a water retention of approximately 93%, which remains the same after irradiation at 32 Mrad. The weight loss in sulfuric acid at a concentration of 10% after 100 hours of treatment is approximately 0, 4%, while the voltage drop at 25 ° C is 0.84-0.75-0.68-1.26 5L cm2 in sulfuric acid 10-20-30-50% (measurement made at 1000 Hz). The final polyantimonic acid content is approximately 3.3% of the total weight of the membrane.

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Example 6

The film is prepared as in Example 1, but using polyethersulphone sold by the company ICI under the name VICTREX. This film has a polyantimonic acid content of 3.3% relative to the total weight of the film, a water retention of 95%, which remains constant after irradiation at 32 Mrad.

The weight loss after treatment with 10% sulfuric acid for 400 hours is approximately 0.5%. The voltage drop measured at alternating current of 1000 Hz is 0.83; 0.76; 0.67; 1.23 ß cm2 in sulfuric acid of 10, 20, 30, 50% respectively.

Example 7

A suspension of a polytetrafluoroethylene (PTFE) powder in 1,2-dichloroethane is prepared, to which Sb ^ O ^ is added in an amount of 20% relative to the total weight. The suspension is poured onto a flat glass support and the solvent is allowed to evaporate. The film thus obtained is hot pressed at a pressure of 3 kg / cm 2 and it is brought to the sintering temperature of PTFE. The film obtained has a water retention of approximately 25%, whereas after treatment for 100 hours in sulfuric acid of 10%, the water retention is approximately 15%. The voltage drop in sulfuric acid at 10, 20, 30, 50% respectively is 1.8; 2.7; 3.2; 4.7 If cm2 respectively.

Example 8 Same preparation as according to Example 1, but polyethylene glycol having a molecular weight of 6000 is added to the N-methylpyrrolidone solution. The amount of polyethylene glycol is 5% by weight relative to the total weight of the film.

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The film thus obtained has a water retention of 99% y and after treatment with sulfuric acid of 10% for 100 hours, the water retention is 97%. The voltage drop in sulfuric acid of 10, 20, 30, 50% respectively is 0.6; 0.5; 0.4; 0.9 51cm2 respectively.

Example 9 To a solution of 10 ml of 1,2-dichloroethane containing poly-sulphone, Sb2C> 2 is added in an amount of 20% by weight relative to the total weight. The solution is poured onto a flat glass support and the solvent is allowed to evaporate. The film thus obtained has a water retention of approximately 70% and approximately 68% after treatment in sulfuric acid by 10% for 100 hours. The voltage drop in sulfuric acid with a concentration of 10, 20, 30, 50% is 1.5; 1.8; 2.0; 2.5 51 cm2 respectively.

Claims (4)

1. Separator film for an electrolyser of moderately tritiated acid water, characterized in that it contains a binder consisting of an organic polymer such as a polysulphone, a poly-ethersulphone, a polyphenylene sulphide, or a polytetrafluor-ethylene , as well as between 70 and 1% by weight, preferably between 55 and 4% by weight, of polyantimonic acid. 2. Method of manufacturing a separator film according to claim 1, characterized in that an organic polymer such as a polysulphone, a polyethersulphone, a polyethylene sulfide or a polytetrafluoroethylene is dissolved in a solvent which is soluble in water , add to this solution of SbCl ^, pour this mixture on a flat support, let the solvent disappear, treat the film thus obtained with water at a temperature below 50 ° C, then remove the film from said support and finally put it in deionized water for 24 hours. 3. Method according to claim 2, characterized in that N-methylpyrrolidone or 1,2-di-chlorine-ethane is used as solvent. 4. Method according to claim 3, -characterized in that added to said solvent polyethylene glycol having a molecular weight of 6000 to an amount between 0.5 and 35% of the total weight of the final film, preferably between 1 and 20 %. f / Jr / \\ Luxembourg, ffiJ / 'f i \ for the Commission' 4 / ¢ / T