JPH0553530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides dialysis,
The present invention relates to a method of permeation or pervaporation, and in particular provides a method that enables separation that could not be achieved with conventional ion exchange membranes.

[Prior art and its problems]

Conventionally, when dialysis and osmosis are performed using an ion exchange membrane, the driving force is the potential gradient applied to both sides of the ion exchange membrane, concentration gradient, pressure difference, temperature difference, hydrogen ion concentration difference in the solution, etc. limited. Regarding ion exchange membranes, in order to improve or decrease ion selective permeability, or change the selective permeability between ions of the same sign,
Various methods have been tried. In addition, in an attempt to impart new functions to ion-exchange membranes, a method of impregnating and polymerizing polymerizable vinyl monomers into ion-exchange membranes has been carried out, reducing the amount of salt that diffuses through the membrane and increasing the transfer number. Improved ion exchange membranes have been proposed that have resulted in reduced acid or base leakage. However, in these methods, the vinyl monomer is generally polymerized within the ion-exchange membrane in many cases, so the ion-exchange membrane itself is swollen by the vinyl monomer, and the resulting improved ion-exchange membrane has mechanical problems. There is a problem that leads to a decrease in strength. It has also been reported that condensation monomers can be condensed within an ion exchange membrane, but this often requires heat treatment to complete the condensation reaction, which impairs the performance of the ion exchange membrane. A problem arises. That is, improvements to such ion exchange membranes are limited to simply controlling the pore size of ordinary ion exchange membranes, changing the charge of the ion exchange groups, and changing the density of the ion exchange groups.

[Means for solving problems]

In view of the above, the present inventors generally change the properties of an anion exchanger and impart new functions to the ion exchanger by forming a matrix of another polymer in the matrix of an ion exchange resin. We have repeatedly considered whether this is possible. As a result, we found that an ion exchange membrane in which a base molecule having electron conductivity is present functions extremely effectively as a separation membrane, which led us to propose the present invention. That is, the present invention is a separation method characterized by using an ion exchange membrane in which a polymer compound having electronic conductivity is present in separating solutes from each other, solvents from each other, or solute and solvent.

Examples of the electronically conductive polymer compound to be present in the ion exchange membrane used in the present invention include conventionally known compounds obtained by polymerizing the following compounds. In other words, there are no restrictions on compounds that exhibit electronic conductivity when polymerized by catalysts, electrical energy such as electrolysis, ionizing radiation such as α, β, and γ, discharge such as X-rays, ultraviolet rays, plasma, and glow. used. Specifically, examples include pyrrole and its derivatives, N-alkylpyrroles such as N-methylpyrrole and 2-ethylpyrrole, thiophene derivatives such as thiophene and 3-alkylthiophene, isothianaphthene and its derivatives, indole, azulene, furan, aniline,
One or more derivatives of phenol, benzene, naphthalene, quinolines, phenylenediamines, acetylene, etc. are preferably used. In particular, heterocyclic compounds such as pyrrole, indole, azulene, quinoline, thiophene, furan, and their derivatives, and acetylene have good affinity with ion exchange membranes, and may be ion-exchanged and uniformly dispersed in the ion exchange membrane. preferable. These are polymerized by the method described above to give a polymer compound having electronic conductivity.

Further, as the ion exchange membrane in which the polymer compound having electronic conductivity is present, any conventionally known ion exchange membrane can be used without any restriction as long as it is a polymer membrane having ion exchange groups bonded thereto. That is, not only organic ion exchange membranes but also inorganic anion exchange membranes formed into a membrane by means of heating, pressurization, etc. using appropriate organic/inorganic binders are also suitably used. . Polymerized ion exchangers, so-called styrene-divinylbenzene copolymers with ion exchange groups bonded to them, are used as organic ion exchange membranes.
A condensed ion exchanger having an ion exchange group bonded thereto is preferably used. As such an ion exchanger, conventionally known homogeneous or heterogeneous ion exchangers can be used, and the substrate of the ion exchanger may be hydrocarbon-based, carbon fluoride-based, perfluorocarbon-based, etc. Suitable for use regardless of how. An ion exchange membrane particularly suitable for the present invention is not particularly limited as long as it has generally 0.1 to 15 milliequivalents of ion exchange membrane bound per gram of the dried ion exchange membrane. As the ion exchange group, conventionally known cation exchange groups or anion exchange groups can be suitably used without any restriction. Examples of cation exchange groups include sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphorous acid groups, phenolic hydroxyl groups, perfluor tertiary alcohols, thiol groups, sulfuric acid ester groups, phosphoric acid ester groups, and metal complex salts. Alternatively, any material that dissociates in a polar organic solvent and becomes negatively charged may be used without any restriction. In addition, as anion exchange groups, onium bases such as primary, secondary, and tertiary amines, quaternary ammonium, tertiary sulfonium, quaternary phosphonium, and cobalticinium, and metal complex salts can be dissociated in water or polar organic solvents. There are no restrictions on what is positively charged. Such ion exchange membranes do not necessarily have only one type of ion exchange group bonded to them;
It is also effective when multiple types of ion exchange groups are bonded, and specifically, an anion exchange membrane in which a mixture of one or more types of primary, secondary, tertiary amines, and onium bases are bonded is suitable. .

Further, in the case of a cation exchange membrane, it is preferable that a carboxylic acid group and a sulfonic acid group exist at the same time.

Of course, a case where a cation group and an anion exchange group are present at the same time can also be suitably used depending on the purpose.

Therefore, the ion exchange membrane of the present invention can be effectively applied to all of cation exchange membranes, anion exchange membranes, amphoteric ion exchange membranes, bipolar ion exchange membranes, mosaic ion exchange membranes, and the like.

Furthermore, membranes in which the distribution of ion exchange groups differs with respect to the cross section of the membrane, such as membranes in which ion exchange groups are densely present on one side of the membrane and sparsely present on the other, and ion exchange groups in the surface layer of the membrane, A membrane in which a thin layer with a charge opposite to that of the exchange group of the exchange membrane exists can also be effectively used. In addition, there are porous ion exchange membranes, in which a thin layer of dense ion exchange membrane exists on the surface layer of the porous membrane, or ion exchange groups are uniformly bonded to form a dense layer only on the surface layer. In particular, porous membrane-like materials to which ion exchange groups are bonded are extremely effective depending on the purpose of use. In this case, the porosity and thickness of the membrane are appropriately selected depending on the purpose of use, but porosity of 95% and thickness of 0.0001 to 2.0 cm are generally suitable, respectively.

As the ion exchange membrane with the above-mentioned asymmetric structure, it is particularly preferable that the surface layer of the porous ion exchange membrane be
This is the case when a dense ion exchange membrane layer of 0.1 to 20 microns is present.

Note that the present invention is not limited to the case where a membrane material having an ion exchange group as described above is used, but also a membrane material having electronic conductivity that has a functional group that can be easily converted into an ion exchange group. The ion exchange group may be introduced after the compound is present. For example, a method of impregnating and polymerizing a polymer membrane bonded with haloalkylstyrene or the like with a compound having electronic conductivity as described above, and then reacting it with amines to introduce an anion-changing group; There is a method in which a monomer is used to make a membrane-like material, a compound having electron conductivity is present in the membrane-like material, and then the ester group is hydrolyzed to obtain the cation exchange membrane of the present invention.

In the present invention, the polymer compound having electronic conductivity is present in the ion exchange membrane as follows:
Both those that exist uniformly and those that exist non-uniformly with respect to the cross section of the ion exchange membrane are effective in the separation method of the present invention depending on the purpose. That is, the selection is made depending on the purpose, such as when it exists only on both surfaces of the cross section of the ion exchange membrane, or when it exists only inside the membrane. Generally, it is preferable that the proportion of the polymer having electron conductivity in the ion exchange membrane increases from 0.1% to 800% of the dry weight of the ion exchange membrane.
The presence of a polymer compound having an electronic conductivity lower than the above range in the ion exchange membrane has a weak effect, and when it exceeds the above range, the membrane becomes extremely hard and brittle, which is not preferable. It is preferable that the ion exchange membrane contains a material that maintains mechanical strength, such as an inert woven fabric, nonwoven fabric, or net.

The method of making the polymer having electron conductivity of the present invention exist in the ion exchange membrane is not particularly limited, and may be carried out according to the conventional method depending on the compound to be present, the type of ion exchange membrane, and the purpose of using the ion exchange membrane of the present invention. The selection is performed by a known method or an easily conceived means.

Generally, a dopant is present in the polymer compound having electron conductivity in the ion exchange membrane of the present invention to impart electron conductivity. When such doping is necessary, conventionally known doping agents are widely used, such as ClO ₄ ^- ,
PF ₄ ^- , AsF ₄ ^- , Cl ^- , F ^- , Br ^- , I ^- , FeCl ₃ , styrene sulfonic acid, polystyrene sulfonic acid, perfluorocarbon sulfonic acid, toluene sulfonic acid, benzene sulfonic acid, rose bengal, anthraquinone disulfate , tetra(sulfonyl)porphyrin, tetrasulfophthalanine, bathophenanthroline disulfate, bathophenanthroline, polyvinyl sulfate, PtCl ₄ ^2- , AuCl ₄ , PdCl ₄ ² Fe
Known compounds such as (CN) ₆ ^3- , RuO ₄ ^- and MnO ₄ can be used without any restriction. Further, as the cation, for example, alkali metal ions such as Na ⁺ , K ⁺ , Li ⁺ , polyvalent metal ions, organic ammonium ions, etc. are used.

Dialysis and osmosis in the separation method of the present invention are
It is the movement of solutes or solvents across an ion exchange membrane from one side of the membrane to the other. Here, the solute refers to inorganic or organic ionic substances, such as soluble salts such as sodium chloride, acids, and bases. Furthermore, there are no restrictions at all as long as the organic ionic substance is a compound having a molecular weight of less than 1000, preferably 500 or less, and has a dissociable functional group bonded within the molecule. In addition, solvents that migrate through osmosis include polar solvents such as water, alcohol, and ketones, or solvents that do not destroy the resin structure of the ion exchange membrane of the present invention or significantly swell, such as amine, amide, aromatic, and fatty solvents. It can be used for infiltration regardless of family type.

Conventionally, the energy required to carry out these dialysis and/or infiltration is a potential gradient,
Concentration gradients, pressure differences, hydrogen ion concentration differences, temperature differences, etc. are used. Alternatively, it can be effectively used to separate organic solvents from each other or from water and organic solvents by pervaporation. In the present invention, since a polymer having electron conductivity is present in the ion exchange membrane, the polymer is brought into an oxidized state or a reduced state by imparting an oxidation or reduction potential specific to the polymer. Accordingly, the permeability of the ion exchange membrane as a separation membrane can be varied, the permeability of solvents and solutes can be changed, and the permeability between solvents and between solutes can also be changed.

In general, p-type and n-type polymers are known as polymers having electronic conductivity, but in the present invention, the cation exchange membrane may have the n-type, and the anion exchange membrane may have the p-type. Most preferred, but not limited to. That is, depending on the polymer having p-type or n-type electronic conductivity, a cation or anion is doped as a dopant, but in this case, the dopant is not limited to the above-mentioned ones. The cationic species and anionic species that pass through will play the role of dopants.

[Effect]

Although it is not clear why the presence of the electronically conductive polymer in the ion exchange membrane in the separation method of the present invention changes the characteristics of the separation membrane, it is clear that the oxidation state of the polymer, This seems to be because the structure of the polymer changes depending on the reduction state, and at the same time, the polarity affects the ions and solvent. At the same time, this is probably because this type of polymer generally has a dense structure and causes changes in the dense structure, pore size, etc. of the membrane.

〔effect〕

The method of the present invention adds a new element to the field of separation technology using conventional ion exchange membranes, making it possible to perform more precise separation. For example, to give a specific example, when performing electrodialytic concentration of a dilute acid aqueous solution using a normal anion exchange membrane and a cation exchange membrane, the current efficiency is extremely low and the concentration of the concentrated acid is also low; When the anion exchange membrane of the present invention is used in a doped state, concentrated acid can be obtained at extremely high current efficiency with almost no increase in the electrical resistance of the membrane.

〔Example〕

Hereinafter, the contents of the present invention will be specifically explained in Examples. The present invention is not limited to the following examples.

Example 1 Styrene, divinylbenzene, and chloromethylstyrene were made into a viscous liquid in the presence of fine polyvinyl chloride powder, applied to a polyvinyl chloride cloth, and polymerized by heating to form a polymer film. This was immersed for 24 hours in a solution of 30% trimethylamine, water and acetone in a ratio of 1:1, and the chloromemory group was reacted with trimethylamine to form an anion exchange membrane having a quaternary ammonium salt. Its exchange capacity was 2.8 meq/g dry membrane and the thickness was 0.16 mm.

This anion exchange membrane was then coated with 5% pyrrole.
After immersing it in an aqueous solution for 24 hours to ensure sufficient adsorption into the membrane, it was immersed in 10% FeCl ₃ and left for 8 hours. The pyrrole impregnated in the membrane oxidized and polymerized, resulting in a pale yellow color. The anion exchange membrane turned black and became hard. When the weight increase of this was measured, it was 320%. This membrane was mixed with 1.0N hydrochloric acid and 0.5
The unpolymerized pyrrole and iron chloride in the membrane were removed by alternately immersing it in specified ammonia water, and the membrane was equilibrated with 1.0N hydrochloric acid. When the electrical resistance of this was measured under 1000 cycles of alternating current, it was 1.8Ω-cm ² (25.0°C).

Using this membrane, it was assembled into a two-chamber cell equipped with silver-silver chloride electrodes, and 6.0N hydrochloric acid was poured into the anode side.
When the cathode chamber was filled with 0.5 N hydrochloric acid and electrodialysis was performed at a current density of 1.0 A/dm ² , the current efficiency was 75%. On the other hand, when electrodialysis was performed under the same conditions using an anion exchange membrane without polypyrrole, the current efficiency was -620% and electrical transfer occurred.
The amount of Cl ^- that diffused due to the concentration gradient was greater than the amount of Cl ^- .

Example 2 Commercially available strong basic anion exchange membrane (Tokuyama Soda Co., Ltd.)
Neocepta AFN) was immersed in a 1:1 (weight ratio) solution of aniline and methanol for 48 hours.
After thorough impregnation, it was immersed in a 10% solution of (NH ₄ ) ₂ S ₂ O ₈ for 16 hours for polymerization. When the membrane was taken out and its dry weight was compared, it was found that the weight had increased by 250%, and the electrical resistance in 1.0N hydrochloric acid was 1.3Ω-cm ² . Note that the electrical resistance of the anion exchange membrane before treatment was 0.7Ω-cm ² .

Using the above-treated anion exchange membrane, a commercially available cation exchange membrane (manufactured by Tokuyama Soda Co., Ltd., Neoceptor) was used.
CM-1) and were arranged in order to form a multi-chamber electrodialysis tank with an effective current-carrying area of 1 dm ² . When seawater was concentrated using this electrodialysis tank,
A 3.7 normal concentrated solution was obtained with a current efficiency of 93%. In addition,
The water temperature was 30°C and the current density was 3.0A/ ^dm2 .

For comparison, seawater concentration was performed under the same conditions in an electrodialysis tank formed in the same manner as above using an anion exchange membrane before treatment, and the results were as follows.
3.2 Normal concentrated solution was obtained with a current efficiency of 80%.

Example 3 Cation exchange membrane (Neosecepta CM-1)
As a Na type, it is installed in a device that can react only on one side of the membrane, and only one side of the membrane is diluted with 5% pyrrole aqueous solution.
After contacting for an hour, a 10% aqueous solution of (NH ₄ ) ₂ S ₂ O ₈ was brought into contact with the membrane surface that was in contact with pyrrole for 1 hour.
Polypyrrole was impregnated and polymerized only on one membrane surface of the cation exchange membrane. When the weight increase of this membrane was compared with the dry state of the membrane, it was 0.2%.

In an electrodialysis tank in which the above treated membrane was assembled into a two-chamber cell equipped with silver-silver chloride electrodes,
When a solution containing CaCl ₂ and 0.25N NaCl in a ratio of 1:1 (by weight) was electrodialyzed at a current density of 1.0 A/dm ² , when 1 equivalent of Na ⁺ permeated the membrane,
Only 0.7 equivalents of Ca ²⁺ permeated the membrane. On the other hand, when electrodialysis was performed in the same manner using a pre-treated cation exchange membrane (Neosepta CM-1) impregnated with pyrrole and not polymerized, 2.1 equivalents of Ca ²⁺ per 1 equivalent of Na ⁺ permeated the membrane.

Example 4 The strongly basic anion exchange membrane (Neosepta AFN) used in Example 2 was installed in an apparatus capable of reacting only one side of the membrane, and only one side was brought into contact with a 5% aqueous solution of pyrrole for 5 hours, and then the same membrane was 3 of FeCl ₃ on the surface
% aqueous solution for 2 hours to polymerize pyrrole. The weight increase of this treated membrane was 3%.

Using this treated anion conversion membrane, a mixed solution of 2.0N HCl and 1.0N FeCl ₂ was placed on the pyrrole-impregnated and polymerized membrane side, and pure water was placed on the other side for diffusion dialysis. As a result, the amount of hydrochloric acid permeated through the membrane was
8.2 mol/hr.m ² (mol/l), and the membrane permeation ratio of iron chloride to hydrochloric acid was 1.5×10 ⁻³ .

For comparison, diffusion dialysis was performed in the same manner using the above anion exchange membrane (untreated membrane) that was not impregnated with pyrrole and the amount of hydrochloric acid permeated through the membrane was as follows.
The ratio of hydrochloric acid to iron chloride in the permeable membrane was ² ×10 ⁻² .

Example 5 A reverse osmosis membrane (exchange capacity 0.3 meq/g dry membrane) obtained from sulfonated polyether sulfone was immersed in a 5% aqueous solution of pyrrole and left for 6 hours to fully impregnate the membrane. When it was immersed in a 5% aqueous solution of ferric chloride and left for 6 hours, it turned black and the pyrrole had polymerized. Using this treated reverse osmosis membrane, an osmosis experiment was conducted with 0.5N saline at 50 atmospheres, and the water permeation rate was 1.4m ³ /hr·day, and the salt rejection rate was 98%.

For comparison, a similar osmosis experiment was conducted using the above-mentioned untreated reverse osmosis membrane, which had not been impregnated with pyrrole and polymerized, and the water permeation rate was 1.5 m ³ /hr, and the salt rejection rate was
It was 90%.

Example 6 Using the anion exchange membrane impregnated with pyrrole used in Example 4, ethyl alcohol mixed with 20% water was subjected to pervaporation. A membrane area of 1 dm ² was placed on a stainless steel perforated plate with the pyrrole-impregnated side facing up, the top and bottom were sealed, the top of the membrane was filled with an alcohol aqueous solution, and heated to 60°C.
The pressure at the bottom was reduced to 10 mmHg. As a result, the ratio of water to ethyl alcohol passing through the membrane is 1
Compared to that, ethyl alcohol was 1/500, and the amount of permeate was 45 c.c./dm ² ·hr. On the other hand, when the same pervaporation as above was carried out using an untreated anion exchange membrane that had not been impregnated with pyrrole and polymerized, the ratio of the amount of permeated liquid of ethyl alcohol to water was 1/
55, and the amount of permeate was 44 c.c./dm ² ·hr.

Example 7 A polyethylene film (thickness: 0.2 mm) was impregnated with styrene-divinylbenzene together with benzoyl peroxide and polymerized to obtain a film.
The amount of impregnated polymerization was 30%. One surface of this membrane was chlorosulfonated with chlorosulfonic acid, and then hydrolyzed with 1N-NaOH to introduce sulfonic acid groups into half of the membrane.
This membrane was then treated with chloromethyl ether and SnCl ₄
20% N, N, N',
Amination treatment was carried out by immersing N'-tetramethylethylenediamine in a methyl ethyl ketone solution. As a result, a so-called bipolar ion exchange membrane was obtained in which a sulfonic acid group was present on one side of the membrane and a quaternary ammonium base was present on the other side.

This bipolar ion exchange membrane was placed in a reaction tank where only one side of the membrane could react, and only the side of the membrane where anion exchange groups existed was brought into contact with a 20% methanol solution of aniline for 2 hours to impregnate it. was contacted with a 10% aqueous solution of (NH ₄ ) ₂ S ₂ O ₈ to polymerize aniline within the membrane. Hydrolysis of 1.0N saline water was carried out using this membrane. That is, a cell consisting of six chambers as shown in FIG. , and 1.0 normal saline solution in the chamber,
The chamber was filled with 0.1N NaOH and the chamber was filled with 0.1N HCl. Apply current for 16 hours at a current density of 10A/ ^dm2.
When the current efficiency of HCl generation and NaOH generation was determined, the former was 72% and the latter was 78%.

On the other hand, when a bipolar ion exchange membrane not impregnated with aniline and not polymerized was used in the same experiment, the current efficiencies for HCl production and NaOH production were 62% and 65%, respectively.

Example 8 A commercially available amphoteric ion exchange membrane (Neosepta CSV, manufactured by Tokuyama Soda Co., Ltd.) was immersed in a 5% aqueous solution of pyrrole to sufficiently impregnate the membrane, and then soaked in a 5% aqueous solution of cupric chloride. was immersed in the membrane to polymerize within the membrane. When this was used to electrodialyze a 1:1 mixed solution of 0.25N hydrochloric acid and 0.25N common salt at 1.0A/ ^dm2 , H ⁺ permeated the membrane 35 times more selectively than Na ⁺ . . On the other hand, in the case of the amphoteric ion exchange membrane described above in which pyrrole was not impregnated and polymerized, the permeation ratio of H ⁺ to Na ⁺ was 12 times.

Example 9 Polyether sulfone was dissolved in ethylene dichloride and sulfonated with a dioxane-SO ₃ complex. Cation exchange membrane capacity is
It was 0.52meq/gram resin. This was dissolved in N-methylpyrrolidone and cast onto a platinum plate, and the solvent was scattered to form a film on the platinum. This platinum plate was mixed with 10 parts of thiophene, 10 parts of tetramethylammonium perchlorate, and N-methylpyrrolidone.
Electrolytic oxidation polymerization was carried out using a platinum plate as an anode by immersing it in a solution of 10 parts dissolved in 50 parts of water and a platinum plate as a counter electrode. Thiophene penetrated into the sulfonated polyether sulfone film and polymerized. When the polythiophene had grown to the surface of the sulfonated polyether sulfone film that was in contact with the solution, the film was peeled off from the platinum plate electrode and thoroughly washed with 1N hydrochloric acid and saline.

This film was used as a membrane to measure the diffusion of NaCl. That is, when we measured the amount of NaCl diffusion by placing pure water on one side of the film membrane and placing 4.0N-NaCl on the other side, we found that D/δ (δ is the thickness of the film, D is the diffusion constant) is 0.2 × 10 It was ^-6 cm・sec ^-1 . In addition,
Similarly, for a film made only of sulfonated polyether sulfone, the amount of NaCl diffusion (δ/D)
The measurement result was 2.5×10 ^-6 cm・sec ^-1 .

Example 10 Using the anion exchange membrane in which polypyrrole of Example 1 was present, the diffusion of common salt was measured. That is, 4.0N-NaCl was placed on one side of the membrane, pure water was placed on the other side,
A platinum black electrode was inserted on the 4.0N-NaCl side, and a voltage was applied to the membrane used in Example 1 to this platinum black electrode.

Since this anion exchange membrane containing polypyrrole is electrically conductive, the tightened part around the membrane was held down with a platinum plate, and the voltage between this and the platinum black electrode was changed. That is, the diffusion constant (D/δ) of NaCl was determined when +0.1v was applied to the platinum black electrode and when -1.0v was applied. When −0.1V is applied, D/δ is 0.8×10 ^-7 cm・sec ^-1 , which is +1.0V
When the voltage was applied, D/δ was 1.8×10 ⁻⁷ cm·sec ⁻¹ . In addition, with an anion conversion membrane (Neosepta AFN) in which pyrrole is not impregnated and polymerized, no change in the NaCl diffusion constant (D/δ) was observed when voltage was applied under the same conditions. .

Example 11 A perfluorocarbon cation exchange membrane (trade name, Nafion 117) was treated with a mixed solvent of ethyl alcohol and acetonitrile in 5-acetyl-2-
The membrane was immersed in a solution of aminobenzophenone and heated to thoroughly impregnate the membrane. This was taken out, immersed in a heated mixture of m-cresol and polyphosphoric acid, and left for one week to introduce polyisoquinoline into the membrane. After drying this,
Immerse it in a 1:1 mixture of concentrated sulfuric acid and concentrated nitric acid at 70°C.
Nitro groups were introduced into polyisoquinoline.

Using the above cation exchange membrane, NaCl was diffused by applying voltages of +1.5v and -1.5v to the membrane as a platinum black electrode and a counter electrode in the same manner as in Example 10.
When a voltage of 1.5v was applied, the amount of NaCl diffused was five times greater than when a voltage of +1.5v was applied.

Claims (1)

[Scope of Claims] 1. A separation method characterized by using an ion exchange membrane in which a polymer compound having electronic conductivity is present in separating solutes from each other, solvents from each other, or solute and solvent. 2. The separation method according to claim 1, which uses a cation exchange membrane as the ion exchange membrane. 3. The separation method according to claim 1, which uses an anion exchange membrane as the ion exchange membrane. 4. The separation method according to claim 1, which uses an amphoteric ion exchange membrane as the ion exchange membrane. 5. The separation method according to claim 1, which uses a bipolar ion exchange membrane as the ion exchange membrane. 6. The separation method according to claim 1, wherein the separation method is electrodialysis. 7. The separation method according to claim 1, wherein the separation method is diffusion dialysis. 8. The separation method according to claim 1, wherein the separation method is reverse osmosis. 9. The separation method according to claim 1, wherein the separation method is a pervaporation method.