JPS58169873A - Selectively permeable film and its manufacture and liquid fuel cell using said film - Google Patents

Abstract

PURPOSE:To obtain a liquid fuel cell of excellent cell characteristic, by using an ion exchange film of excellent ion permeability further with excellent stopping power for a liquid molecule as the partition film. CONSTITUTION:A selectively permeable film is constituted such that fine particles 3 physically and chemically stable for processed liquid are held in the inside of at least an applicable hole 2 of a porous organic high molecular film 1 to provide fine hole size permeably controlled for only a gas state or liquid low molecular material or ion in said liquid. Holding of the particles 3 decreases virtual size of the hole 2 to improve selective permeability. A fine particle chemically or physically stable for a cell electrolyte, for instance, sulfuric acid and phosphoric acid or the like is only required as the particle held to a porous ion exchange film. Under a condition operated as a fuel cell, the ion exchange film as the partition film contains a cell electrolyte. Here an acid electrolyte of, for instance, sulfuric acid, phosphoric acid, etc. and alkaline electrolyte of potassium hydroxide, sodium hydroxide, etc. are used as the electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a selectively permeable membrane (III) that selectively permeates molecules or ions in a solution, and a liquid fuel recovery pond using this membrane as a diaphragm.

A selectively permeable membrane has a porous structure and is used for separation and other purposes by passing specific molecules or ions through the pores. Here, in order to allow gases, ions, etc. to permeate, the pore size of the K membrane must be particularly small. However, with the industrially available and relatively simple manufacturing methods for porous membranes up until now, the limit is a pore diameter of α1 to 1 μm, and it is difficult to uniformly produce pores with smaller pore diameters. Katsurun.

One object of the present invention is to provide a permselective membrane made of a porous organic polymer membrane with a reduced apparent pore size.

Another objective is to provide a liquid fuel cell with excellent cell properties by using an ion crossing membrane with excellent ion permeability and excellent blocking properties against liquid molecules as a diaphragm. .

The selectively permeable membrane of the present invention has fine particles that are physically and chemically stable with respect to the liquid to be treated supported at least inside the pores of a porous organic polymer membrane. It is characterized by having a micropore diameter controlled so that only molecular substances or ions can pass through it.

According to Akira, by supporting fine particles inside the pores, by reducing the apparent pore diameter, ions, gases, and other low-molecular substances can selectively pass through to relatively large liquid molecules. This was discovered through the discovery of the fact that it exhibits excellent blocking ability against.

FIG. 1 schematically shows a cross section of the Ω selectively permeable membrane of the present invention. In FIG. 1, l is a porous organic polymer membrane, 2
are microparticles supported inside the pores, 3Fi pores 2. By supporting the fine particles 3 in this way, the apparent diameter of the pores 2 becomes smaller and the permselectivity improves.

Known porous organic polymer membranes, ie, materials and manufacturing methods thereof, can be used in the present invention. For example, materials include styrene-divinylbenzene copolymer, styrene-butadiene copolymer, polyethylene, polyvinyl chloride, fluororesin, cellulose acetate, polysulfone, and the like.

In addition, as a method for forming a porous membrane, for example (1) αl~
A method of forming a film by pouring liquid latex having a grain size of 1 μm onto a flat plate and polymerizing the particles, (2) forming a film by dissolving the film material in a solvent, and then vaporizing the solvent to form a porous film. Methods such as (3) irradiating the membrane with neutrons to create holes can be used.

In the present invention, for example, the following method can be used to support fine particles in the pores of a porous organic polymer (hereinafter simply referred to as a membrane).

(1) A method in which a membrane is impregnated with a solution containing a compound that can be converted from a dissolved state into solid fine particles by a chemical reaction, and collectors are generated inside the pores by a chemical reaction.

Specifically, for example, (i) the membrane is immersed in a solution of a chloride such as platinum, ruthenium, or palladium, and the chloride is reduced by adding formalin, sodium borohydride, etc., or by injecting hydrogen to remove the metal. (ii) A method in which the membrane is immersed in an AgNOx aqueous solution and AgC/particles are generated inside the pores using HCt; or (ii) A method in which the membrane is immersed in a Bacz2 water bath solution and H! There is a method of generating B51804 particles inside the pores using B51804.

The apparent pore size can be changed by changing the amount of fine particles supported. Therefore, the supported amount can be arbitrarily selected depending on the target substance to be separated and the type of ions.

Further, as the fine particles, it is preferable to use kumquats that are chemically inert to the liquid to be treated, such as a solvent, in which the substance or ions to be separated are dissolved, or that do not cause any physical change. Therefore, it can be appropriately selected depending on the type of liquid to be treated. Generally, when used in water, M solution salts with a small solubility product such as barium sulfate and chloride scissor particles are used, and when used in acidic solutions, noble metals such as platinum, gold, silver, etc., which have a smaller ionization tendency than hydrogen ions. etc. are appropriate.

The selectively permeable membrane of the present invention is, for example, a reverse immersion 4 membrane for pure water production,
Through the research of woodcutter and others, it can be used as a separation membrane for organic matter removal, a diaphragm for salt electrolysis, an ion crossing membrane for liquid chromatography, a diaphragm for liquid fuel cells, etc.
Among the permselective members mentioned above, Tomo discovered that cell characteristics could be improved by using a permselective membrane using an ion exchange membrane as a diaphragm in a liquid fuel cell. This effect is due to two contradictory actions and effects: the ion exchange membrane (diaphragm) efficiently moves only the ions generated by the fta reaction, and also prevents the liquid fuel from moving to the cathode side. This is due to the fact that this is improved over conventional ion exchange membranes. With conventional ion exchange membranes,
As a large amount of fuel moves to the cathode side, a direct oxidation reaction occurs at the cathode, and the oxygen level at the cathode becomes low F, which lowers the monopolar potential of the cathode, which significantly reduces the battery voltage. I rarely found anything to do. The battery of the present invention is also advantageous in terms of fuel utilization.

The liquid fuel cell of the present invention is a liquid fuel cell including an anode, a cathode, and a diaphragm interposed between the two electrodes, in which the diaphragm is made of porous ions that carry fine particles stable in a battery electrolyte inside the pores. 3! It is characterized by an envious membrane.

The liquid fuel cell of the present invention has improved cell characteristics because the ion exchange membrane used exhibits excellent fuel blocking properties without inhibiting ion permselectivity. This is because the apparent pore size of the ion exchange membrane is small.

In other words, since fuel molecules are large compared to ions, ion permeability is affected by the size of the pores, but this is because fuel molecules have a small diameter and are difficult to pass through. This is because the same holds true for nine months.

An example of the battery of the present invention is shown in Figure @2. Figure 2 shows a schematic Vr side view of the battery, where 4 is an anode, 5 is a cathode, 6 is a fuel, an anolite is a mixture of fuel and battery electrolyte, 7 is a carbon dioxide gas outlet, and 8 is a An oxidizing agent supply port such as air, and a filter 9 are outlets for the oxidizing agent and produced water, and a diaphragm 1 is formed of a porous ion exchange membrane supporting the fine particles.

The particles supporting the porous metal oxide/cross-linked MK may be fine particles that are chemically resistant or physically stable to sulfuric acid, 9-acid, etc. in the battery electrolyte.

Further, when the fine particles are made of platinum, palladium, or ruthenium, which acts as a catalyst for battery reactions, they contribute to improving battery characteristics. The amount of fine particles supported is 0.00000000000000 per unit area of the ion exchange membrane.
The range is generally from 02 to 2η/piece2.

When operating as a fuel cell, the ion exchange membrane as a diaphragm contains a battery electrolyte.

Here, as the electrolytic solution, for example, an acidic brewing solution such as sulfuric acid or phosphoric acid, or an alkaline electrolytic solution such as potassium hydroxide or sodium hydroxide is used.

Methanol, hydrazine, formalin, or formic acid is used as the liquid fuel.

Next, examples of the present invention will be shown.

[Manufacture of selective transmission]

425) was immersed in 0.5 mot/L of platinum chloride plate water bath solution for 1 hour. dried. Next, the platinic acid described above was reduced with 90 tZ' mlF in a hydrogen atmosphere to generate platinum black inside the pores. The chloroplatinic acid soaked in the membrane is
3.2 ■ per 1 crn of film, 1 film as platinum black
It was 1.2 per cr111.

Next, examine the ion permselectivity of the above membrane.

1 through the membrane using the known AC bridging method, i.e.
00OH! A method was used in which the membrane resistance was measured from the Wheatstone bridge balance by flowing a variable current of . As a result, the electrical resistance of the film was α52Ω・i (0.50Ω before treatment)
・Adverse proverb), and it was confirmed that ion permeability did not decrease substantively. On the other hand, as a result of examining the liquid molecule blocking performance, it was found that the following improvement was achieved. The plan is to use methanol as the liquid and its permeation t(Q)
was measured, and then the transmission coefficient was determined based on the F formula, and judgment was made based on whether it was large or small.

Q=pXjTXΔCX5 (Q: methanol permeation amount mol, P: methanol permeation coefficient mol/ (mol/l)・m・cm”,
ΔT: elapsed time, ΔC: methanol concentration difference on both sides of M
ot/l, 8: membrane area 611") Measurement result, P is 0.8 X I Q = mol/ (
mol/l) ・Deception・cm8 (Z OX 1 before processing
0-"mat/ (mol/l)・Seki・31).

Figure 3 shows the relationship between the amount of platinum black supported and the methanol permeability coefficient.
- Show the results of your investigation. The supported amount of platinum black is 1 of chloroplatinic acid.
Adjustment was made by changing the angle of 11 degrees.

Other supporting conditions were the same as in Example 1 above.

As is clear from FIG. 3, it is recognized that as the amount of platinum black supported increases, the methanol permeability coefficient steadily decreases. This shows that by incorporating platinum black fine particles, the apparent pore size of the membrane can be reduced and the ability to block liquid molecules can be improved.

Further, FIG. 4 shows the relationship between the methanol permeability coefficient and the methanol utilization rate. As is clear from FIG. 4, as the methanol permeability coefficient is reduced, the methanol utilization rate can be increased almost proportionally.

Actual flow? 112' A porous cation exchange membrane similar to that in Example 1 was
After being immersed in a barium chloride water bath solution of 0.1 mol/L for 0.5 hour, it was taken out and immersed in about 2 mot/L of sulfuric acid to convert the barium chloride inside the pores into barium sulfate particles. The amount of barium sulfate supported per unit area is 1 q/cm”
So 6th one.

The methanol permeability coefficient of the above membrane is 0.65X10-@mo
t/ (mot/l), deception, and bei3.

Example 3 A cation exchange membrane of Example 1 and Ichikawa was used in an amount of 0.5 to 1 mo.
After being immersed in l/l silver nitrate solution III for 1 hour, it was taken out and immersed in about 2 nnot/t hydrochloric acid to convert the silver nitrate inside the pores into silver chloride particles. Unit area (h
The amount of silver chloride supported per (-) was 0.5'q.

The methanol permeability coefficient of the above membrane is 1.0X10-'mol
/ (mol/l)・W・cm”.

[Production of adult fuel cell]

Example 4 Using the platinum black supported cation exchange membrane produced in Example 1,
A methanol fuel cell (level cell) having the configuration shown in FIG. 2 was manufactured. That is, a cathode and an anode are prepared by coating a tantalum wire mesh with platinum black (1/2/920 cm) as a catalyst and polytetrafluoroethylene (5 #1 Jl) as a binder and then firing. A platinum black supported cation exchange membrane is interposed between the two, and an electrolytic solution containing methanol and dilute sulfuric acid is supplied from the anode side. When air is supplied to the cathode side, oxygen and hydrogen ions combine to produce water. At the anode, methanol reacts with water to generate hydrogen ions, electrons, and carbon dioxide gas. Hydrogen ions are transported to the cathode through a cation exchange membrane. The carbon dioxide gas forms bubbles and is expelled from the battery, and the electrons flow through an external circuit to generate electricity. At this time, platinum black supported cation exchange! [ prevents methanol from reaching the cathode, prevents deterioration of cathode performance, and contributes to improving methanol utilization efficiency. FIG. 5 compares the cell voltage performance of the above fuel cell (curve mA) and the fuel cell using untreated cation exchange membrane (curve B). The example using a platinum black-supported cation exchange membrane had an output of 50 mA/cm.
When comparing the single flow density of , an improvement in battery voltage of 0.03 V was observed compared to when an untreated ion exchange membrane was used.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the cross-sectional structure of a permselective membrane according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the cross-sectional structure of a liquid fuel cell (unit cell) according to an embodiment of the present invention. Figure 3 is a graph showing the relationship between the amount of platinum supported and the methanol permeability coefficient of a selectively permeable membrane which is an embodiment of the present invention, and Figure 4 is a graph showing the methanol permeability coefficient of a selectively permeable membrane which is also an embodiment of the present invention. Graph showing the relationship between and methanol utilization rate and ijg5
The figure is a graph showing the relationship between #, flow density, and cell voltage of a liquid fuel cell according to an embodiment of the present invention. l...Porous polymer membrane, 2...pores, 3...fine particles, 4...anode, 5...cathode, 6...fuel or anola χ l Opening curtain z Illustration 3 t3 receiver, black teacher li quantity and guy/cgz) 鑵4 figure

Claims (1)

[Claims] 1. Fine particles that are physically and chemically stable with respect to the liquid to be treated are supported at least inside the chain pores of the porous organic polymer membrane,
It is characterized by having a micropore diameter that is controlled so that only gaseous or liquid low molecular weight substances or ions in the liquid can pass through it. The fourth claim characterized in that
The selectively permeable membrane described in Section 1. 3. The selectively permeable membrane according to claim 1 or 2, wherein the porous organic polymer membrane is an ion exchange membrane. 4. The selectively permeable membrane according to claim 2, wherein the controlled pore diameter is such that only hydrogen ions in the liquid to be treated can pass therethrough. 5. The selectively permeable membrane according to claim 11g4, wherein the fine particles are a compound of a noble metal that has a smaller tendency to ionize than hydrogen ions. 6. The selectively permeable membrane according to claim 4, wherein the ion exchange membrane is selected from synthetic resin, synthetic cellulose-1, and natural cellulose. 7. The selectively permeable membrane according to claim 4, wherein the ion exchange membrane is selected from synthetic resin, synthetic cellulose, and natural cellulose. 8. A porous organic polymer membrane is impregnated with a solution containing a compound that can be converted into solid particles by a chemical reaction, and fine particles are generated at least inside the pores by the chemical reaction. Manufacturing method of selectively permeable membrane. 9. A method for producing a selectively permeable membrane, which comprises impregnating a porous organic polymer membrane with a solution containing a solid compound and removing the solvent to generate particles at least inside the pores. 10. In a liquid fuel cell, which refers to a diaphragm interposed between an anode, a cathode, and both electrodes, the diaphragm has a well-controlled pore size by carrying particulates stable in the battery electrolyte inside the pores. A liquid fuel cell characterized in that it is a porous ion cation exchange membrane. 11. The liquid fuel cell according to claim 1θ, wherein the fine particles act as a catalyst for the 'wlL pond reaction. 12. The liquid fuel cell according to claim 111, wherein the # particles are at least one selected from platinum, palladium, and ruthenium. 13. The amount of fine particles supported per unit area of the diaphragm is 0.02
Claims 7 and 9 are the liquid fuel cell according to claim 11, characterized in that the electrolyte is an acidic electrolyte. A liquid fuel cell according to claim 10 or 11.