JPH09227698A - Anion-exchange membrane with crosslinked structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the resistance and also to improve the ion selectivity and corrosion resistance of a specified haloalklated block copolymer by reacting it with a monoamine and a polyamine. SOLUTION: A haloalklated aromatic polysulfonic block copolymer comprising a segment of formula I [wherein Ar is represented by formulae II to IV; Y is a single bond, O, S or the like; R<1> to R<7> are each a 1 to 8C hydrocarbon group; (a) and (b) are each 0 to 4; (c) is 0 to 3; (d+e) is 0 to 7; (f+g) is 0 to 5; and R<8> and R<9> are each a 1 to 6C hydrocarbon group) and a block of formula V (wherein X is a single bond, SO2 or the like; R<10> to R<11> are each a 1 to o 5C hydrocarbon group; and (h) and (i) are each (a)), m/n being 100/1 to 1/10], is reacted with a monoamine to react 30 to 50 molar % of the haloalkyl groups. Then the reaction mixture is reacted with a polyamine to give an anion- exchange membrane having an AC specific resistance in 0.5M sulfuric acid at 25 deg.C of not higher than 300 Ω.cm and a water migration rate of not higher than 3g.cm/m<2> .h∼M at 40 deg.C from the water side to the sulfuric acid side when sulfuric acid is left to flow on one side of the membrane and water is left to flow on the other side.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anion exchange membrane having a crosslinked structure, and an anion exchange membrane using the anion exchange membrane.
The present invention relates to a method for performing diffusion dialysis such as acid recovery, seawater concentration, electrodialysis such as acid concentration recovery, and organic and inorganic electrolysis.

[0002]

2. Description of the Related Art As an anion exchanger, a number of documents,
Patents reported, but most practical and beneficial are chloromethylated styrene (or vinyl pyridine)
-Aminated (or quaternary pyridiniumized) anion exchangers of divinylbenzene copolymers. These products can be used in a wide variety of products for all applications, because their ion exchange properties and permselectivity can be controlled by changing the content of divinylbenzene, a crosslinking agent, in addition to chemical resistance, heat resistance, and ion exchange properties. Has been synthesized and developed.

However, new needs such as efficient recovery of highly oxidizing acids such as hydrofluoric acid and nitric acid, recovery of acids containing oxidizing metals, recovery of phosphoric acid from phosphoric acid etching waste liquid in the aluminum industry, industrial salts Concentration of seawater to produce ordinary inexpensive salt, low resistance and low water transfer rate for use in electrolysis of liquids containing electrolytes and organic substances, and for the demand for ion exchange membranes with corrosion resistance,
There is a drawback that conventional styrene-divinylbenzene-based copolymer membranes cannot deal with. That is, to reduce the resistance, chloromethylated styrene (or vinyl pyridine)
It is necessary to increase the content, decrease the amount of divinylbenzene in the cross-linking agent, increase the ion exchange capacity and increase the water content, but in addition to the decrease in mechanical strength, the selective permeability and corrosion resistance also decrease, and liquid transfer The required film cannot be obtained due to the increased amount. Further, as another means for lowering the resistance, it is necessary to reduce the film thickness. However, since the styrene-divinylbenzene copolymer film has mechanical strength, especially brittleness, an ion exchange film of 100 μm or less is required. I can't get it.

On the other hand, engineering plastics having excellent mechanical strength and workability are used in ultrafiltration, separation membranes such as reverse osmosis membranes and gas separation membranes. Especially, the polysulfone membrane, which has excellent chemical resistance, has ion exchange groups introduced into the membrane to improve the permeability in ultrafiltration and reverse osmosis and to impart ion selective permeability, making it suitable for use in ion exchange membranes. Is being considered.

For example, an anion exchange membrane synthesized from chloromethylated polysulfone having a repeating unit represented by the formula (d) is described in J. Membrane Scienc.
e, 22 (1985) 325-332.

[0006]

Embedded image

However, these polysulfone type ion exchange membranes are non-crosslinked, and when the ion exchange capacity is increased and the resistance is lowered, the ion selectivity and the corrosion resistance are lowered, and the water transfer rate is increased. There was a drawback to do.

As a method of compensating for these drawbacks, an anion exchanger having a crosslinked structure having a structure obtained by reacting a chloromethylated product of a polysulfone polymer with a polyamine has been proposed (JP-A-2-68146).

[0009]

The membrane obtained by using this anion exchanger having a novel crosslinked structure has low resistance and high ion selectivity under certain reaction conditions, but it has a low water transfer rate. High speed, for example, in the recovery of acid by diffusion dialysis in which waste acid is flown to one side and water is flown to the other side to recover the acid, a large amount of water is transferred from the water side to the waste acid side, increasing the amount of waste liquid, Further, in the concentration and recovery of the electrolyte by electrodialysis, a large amount of water moves from the dilution side to the concentration side, so that the concentration concentration of the electrolyte does not increase and it is not possible to meet various new needs.

The present invention is intended to solve the above-mentioned drawbacks of the prior art, and provides a crosslinked structure having a low resistance, a high ion selectivity, a low water migration speed, and an excellent corrosion resistance. It aims at providing the anion exchange membrane which has.

[0011]

The present invention has the general formula (a):
A haloalkylated aromatic polysulfone block copolymer having a segment represented by the following formula and a segment represented by the general formula (b), wherein m / n = 100/1 to 1/10,
An anion exchange membrane having a crosslinked structure reacted with a monoamine and a polyamine, wherein the ratio of the haloalkyl group reacted with the monoamine to the whole haloalkyl group is 30.
.About.50 mol%, ion exchange capacity is 1.0 to 3.5 meq / g dry resin, AC specific resistance in 0.5 M sulfuric acid at 25.degree. C. is 300 .OMEGA.cm or less, and sulfuric acid is applied to one side of the membrane. The moving speed of water from the water side to the sulfuric acid side when flowing water to the other side at 40 ° C is 3 g · cm / m ² · h · M
An anion exchange membrane is provided that is:

[0012]

Embedded image

The anion exchange membrane of the present invention has an aromatic polysulfone system having a segment (a) which is easy to introduce a haloalkyl group for introducing an ion exchange group into the molecule and a segment (b) which is difficult to introduce a haloalkyl group. Using block copolymers, the block-introduced haloalkyl groups are reacted with monoamine and polyamine in a specific ratio to achieve the conflict of low electrical resistance and high ion selectivity, low water migration rate, corrosion resistance, and high mechanical strength. The feature is that both the characteristics to be achieved are compatible.

When the ratio of m in the general formula (a) to n in the general formula (b) (m / n) is larger than 100/1, the pseudo-crosslinking effect due to the portion where the ion-exchange group is not introduced is reduced and the water is reduced. This is unsuitable because the moving speed increases. m / n is 1/1
If it is smaller than 0, the ion exchange capacity is lowered and the electric resistance is increased, which is not suitable. m / n is 5/1 to 1
The case of / 5 is more preferable.

The ratio of the haloalkyl group reacted with the monoamine to the haloalkyl group reacted with the polyamine is preferably 30 to 50 mol% of the haloalkyl group reacted with the monoamine with respect to the entire haloalkyl group. When the ratio of the haloalkyl group reacted with the monoamine is larger than 50 mol%, the electric resistance of the membrane is low but the water migration rate is high, which is unsuitable. When the ratio of the haloalkyl group reacted with the monoamine is lower than 30 mol%, the degree of cross-linking becomes too high and the water transfer amount of the membrane decreases, but the electric resistance sharply increases, which is not suitable.

The optimum ion-exchange capacity of the anion-exchange membrane varies depending on the intended use, but is usually 1.0 to 3.
It is preferable to select so as to obtain 5 meq / g dry resin. If the ion exchange capacity is smaller than 1.0 meq / g dry resin, the electric resistance will increase, which is not preferable. If the ion exchange capacity is larger than 3.5 meq / g dry resin, the water transfer rate becomes high, which is not preferable.

Regarding the electric resistance of the anion exchange membrane, the AC specific resistance in 0.5 M sulfuric acid at 25 ° C. is required to be 300 Ω · cm or less. If the electric resistance is larger than this value, the acid permeability is low in the diffusion dialysis and the acid is not efficiently recovered, and the voltage is increased in the electrodialysis or electrolysis and the energy saving process is not performed, which is not suitable.

The water transfer speed is determined by sandwiching the anion exchange membrane between cells and slowly flowing a sulfuric acid aqueous solution on one side and water on the other side in a countercurrent manner, and calculating from the liquid volume and the sulfuric acid concentration. The effective area of the membrane is A (m ² ), the thickness of the membrane is L (cm), the sulfuric acid solution supply rate and the water discharge rate are v (liter / h), and the sulfuric acid solution discharge rate and the water supply rate are v '(liter). / H), the molar concentration of the supplied sulfuric acid solution is C ₁ (M), and its specific gravity is d
₁ (g / cc), the molar concentration of the discharged sulfuric acid solution is C ₂
(M), its specific gravity is d ₂ (g / cc), the molar concentration of sulfuric acid in the discharged water is C ₃ (M), and its specific gravity is d ₃ (g / c).
c), the water movement speed U (g · cm / m ² · h ·
M) is represented by the following equation. Where ΔM is the average sulfuric acid concentration difference (M) on both sides of the membrane.

[0019]

[Equation 1]

In the above measurement of the water movement speed, A, v, and C ₁ can be arbitrarily determined, but the value of A / v is 0.2 to
In the range of 1.5 (m ² · h / liter), C ₁ is 1
It is preferable to measure at about 5M.

As for the water transfer rate, the transfer rate of water from the water side to the sulfuric acid side when flowing sulfuric acid to one side of the membrane is 3 g · cm / m ² · h · M or less at 40 ° C. It is necessary to be. Water movement speed is 3g · cm / m ²
・ If it is larger than h · M, the amount of waste liquid will increase in diffusion dialysis,
In addition, the concentration of the recovered substance is not increased by electrodialysis or electrolysis, which is inappropriate.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION To obtain the anion exchange membrane of the present invention, the following methods are specifically preferred. First, a block copolymer having the general formulas (a) and (b) is synthesized.
In this copolymer, a structure in which the segment of the general formula (a) and the segment of the general formula (b) are repeatedly bonded to each other by about 2 to 100 is preferable, and the intrinsic viscosity is 0.1 to 3 dl / g. The degree is appropriate.

Next, a haloalkyl group is introduced into this copolymer. A suitable example of the haloalkyl group is a chloromethyl group. When a chloromethyl group is introduced, for example, in a solvent such as a halogenated hydrocarbon such as trichloroethane or tetrachloroethane, the above block copolymer, chloromethyl methyl ether, 1,4-bis (chloromethoxy) butane, 1- A nucleophilic chlormethylating agent such as chloromethoxy-4-chlorobutane, or formalin-hydrogen chloride system or paraformaldehyde-hydrogen chloride system is reacted. At this time, tin chloride or the like can be used as a catalyst.

Next, the haloalkyl group is reacted with the monoamine and polyamine. The method includes the following (1) to (3).

(1) A haloalkyl group-containing block copolymer is dissolved in a solvent, a certain amount of monoamine is added to react a part of the haloalkyl groups, and then a film is formed by casting. The obtained film is placed in a polyamine solution. Method of immersing and reacting,
(2) A method in which the haloalkyl group-containing block copolymer is dissolved in a solvent, a certain amount of a mixture of monoamine and polyamine is added to react the haloalkyl groups, and then cast film formation, (3) haloalkyl group-containing block copolymer Is dissolved in a solvent to form a cast film, and the resulting film is immersed in a mixed solution of monoamine and polyamine to react.

Usually, the method (1) is used to control the ratio of the haloalkyl group reacted with the monoamine and the haloalkyl group reacted with the polyamine with high accuracy.

The polyamine compound used in the present invention includes ethylenediamine, diethylenetriamine,
Triethylenetetramine, tetraethylenepentamine,
Polyamine compounds composed of primary and secondary amines such as polyethyleneimine and phenylenediamine, and N, N, N'N '
-Tetramethyldiaminomethane, N, N, N'N'-tetramethyl-1,2-diaminoethane, N, N, N '
N'-tetramethyl-1,3-diaminopropane, N,
N, N'N'-tetramethyl-1,6-diaminohexane, N, N, N'N'-tetramethylbenzidine, p,
P'-tetramethyldiaminodiphenylmethane, polyvinyl pyridine, and the primary and secondary amination products of polychloromethylene are used. Among them, the diamine having two tertiary amines represented by the general formula (c) at the molecular end is easily available, has high amination reactivity, and the physical properties of the film can be easily controlled by changing the number of methylene groups. It can be used as a particularly preferable polyamine compound because it can be carried out.

[0028]

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The monoamine is preferably a tertiary amine. Specifically, trialkylamines such as trimethylamine, triethylamine and tributylamine, N,
Examples thereof include aromatic amines such as N-dimethylaniline and N-methylpyrrole, heterocyclic amines such as N-methylpyrrolidine and N-methylmorpholine, and alcohol amines such as triethanolamine. Among them, trimethylamine is particularly preferable because a film having low resistance can be obtained.

The anion exchange membrane of the present invention has low electric resistance, high ion selectivity, low water migration rate, corrosion resistance, and high mechanical strength, which are contradictory characteristics, and therefore has a high thickness and high characteristics. . Strictly speaking, the film thickness is determined depending on the application and use conditions, but it is preferably about 5 to 80 μm. If necessary, it can be used as a multilayer with other materials.

In the anion exchange membrane having a crosslinked structure of the present invention, a solution containing an acid is brought into contact with one side of the anion exchange membrane, and water or an acid solution having a lower concentration than that of the opposite side is brought into contact with the other side of the anion exchange membrane. It can be preferably used in a method for recovering an acid in which the acid is selectively subjected to diffusion dialysis from a solution containing.

Specifically, as a method of recovering the acid by diffusion dialysis, anion exchange membranes and spacer nets having a thickness of 0.5 to 5 mm are alternately arranged, and a plurality of acid stock solution side and water side compartments are alternately arranged. It is preferable to prepare and supply the stock solution containing acid and water to the membrane effective area of 1 m ^{2 at} a rate of 0.7 to 5 liter / h. The operating temperature is preferably 25 to 60 ° C. If the temperature is lower than 25 ° C, the acid permeation rate is decreased, and if the temperature is higher than 60 ° C, the heat resistance is required for the material of the cell or the spacer, which is not preferable.

In the anion exchange membrane having a crosslinked structure of the present invention, cation exchange membranes or hydrogen ion exchange membranes and anion exchange membranes are alternately arranged between the cathode and the anode, and the electrolyte solution is passed through. However, it can be preferably used in a method of concentrating and recovering an electrolyte in which voltage is applied and electrodialysis is performed.

As a method for concentrating and recovering the electrolyte by electrodialysis, specifically, a plurality of cation exchange membranes and anion exchange membranes are alternately arranged between an anode chamber having an anode and a cathode chamber having a cathode. Then, a desalting chamber in which the anode side is partitioned by the anion exchange membrane and the cathode side is partitioned by the cation exchange membrane, and a concentrating chamber in which the anode side is partitioned by the cation exchange membrane and the cathode side is partitioned by the anion exchange membrane. About 2 to 300 sets are alternately arranged. Concentration and recovery can be carried out by circulating an undiluted solution containing an electrolyte from the undiluted solution tank in the desalting chamber, and supplying an electric current while circulating an electrolytic solution for recovering the concentrated electrolyte in the concentrating chamber. It is preferable to apply a voltage of about 0.2 to 2 V to each unit cell so that the current value is not more than the limiting current density.

Further, in the anion exchange membrane having a crosslinked structure of the present invention, a cation exchange membrane on the cathode side and an anion exchange membrane on the anode side, or an anion exchange membrane alone is arranged between the cathode and the anode. It can be preferably used for an electrolytic reaction in which a voltage is applied to electrolyze while passing a solution containing an electrolyte or an organic substance.

Specifically, as the electrolytic reaction by electrolysis, a cation exchange membrane on the cathode side and an anion exchange membrane on the anode side, or anion exchange is provided between the anode chamber having the anode and the cathode chamber having the cathode. An electrolytic reaction can be performed by disposing only a membrane and applying a voltage to electrolyze while passing a solution containing an electrolyte or an organic substance through an intermediate chamber or a cathode chamber.
The voltage applied between the electrodes varies depending on the electrolytic reaction performed,
It is preferable to apply a voltage of about 0.2 to 10 V at which the electrolytic reaction sufficiently occurs.

[0037]

【Example】

Example 1 0.36 mol of 4,4′-diphenol and 0.396 mol of dichlorodiphenyl sulfone were reacted in the same manner as in the synthesis method described in JP-A-61-168629 to obtain a unit of aromatic polysulfone. 0.36 mol of a precursor of m = 10 was synthesized, and then 0.36 mol of the precursor and 0.324 of dichlorodiphenyl sulfone were synthesized.
Moles were reacted with 0.378 mol of sodium sulfide to obtain 220 g of an aromatic polysulfone-polythioether sulfone copolymer represented by Chemical formula 6. However, m = n = 10
It is. The intrinsic viscosity of this aromatic polysulfone-polythioether sulfone copolymer was 0.50 dl / g.

[0038]

[Chemical 6]

Next, 75 g of the copolymer was added to 1,1,2,2
-Dissolved in 1020 ml of tetrachloroethane, 400 g of chloromethyl methyl ether and 4.5 of anhydrous tin chloride
g was further added, and the mixture was heated to a temperature of 110 ° C. and the chloromethylation reaction was carried out for 4 hours. After the reaction was completed, the reaction product was precipitated using 5000 ml of methyl alcohol,
This was washed to obtain 85 g of a chloromethylated copolymer.
The introduction ratio of chloromethyl groups in the obtained chloromethylated copolymer was about 1.9 per repeating unit, and the ion exchange capacity when reacted with trimethylamine was 2.2 meq / g dry resin. there were.

50 g of this chloromethylated copolymer was added to N,
Three batches of 15 wt% solution dissolved in 300 ml of N-dimethylformamide were prepared. 53 ml, 48 ml, and 37 ml of 1N trimethylamine N, N-dimethylformamide solution were slowly added dropwise with stirring at a temperature of 0 ° C. under cooling, and then 10 g of 2-methoxyethanol was added, and the ion exchange capacity was 1 413 ml of solution A of 0.0 meq / g dry resin, 408 ml of solution B of 0.9 meq / g dry resin, and 397 ml of solution C of 0.7 meq / g dry resin were obtained.

Each solution was cast at 60 ° C. for 2 hours to form a film,
A film having a thickness of 50 μm was obtained. The obtained film was treated with 1N N, N,
A crosslinked film was obtained by immersing in a methanol solution of N′N′-tetramethyl-1,2-diaminoethane at 50 ° C. for 4 hours.
The proportions of haloalkyl groups reacted with monoamines in these membranes were 45, 41 and 32 mol% for the solutions A, B and C, respectively. The AC resistivity of these films in 25M sulfuric acid at 25 ° C and 4
The moving speed of water at 0 ° C. is a resistance value of 150,
200, 300 Ω · cm, water movement speed 1.80, 1.7
It was 0 and 1.25 g · cm / m ² · h · M.

Example 2 N, N, N'N'-tetramethyl-as polyamine
A film having a crosslinked structure was obtained in the same manner as in Example 1 except that 1,3-diaminopropane was used. The AC specific resistance of 0.5 M sulfuric acid at 25 ° C. and the migration rate of water at 40 ° C. of the obtained membrane were 120, 160 and 26, respectively.
0 Ω · cm, water movement speed 2.10, 2.00, 1.75
It was g · cm / m ² · h · M.

Example 3 N, N, N'N'-tetramethyl-as polyamine
A film having a crosslinked structure was obtained in the same manner as in Example 1 except that 1,6-diaminohexane was used. The alternating current specific resistance of 0.5 M sulfuric acid at 25 ° C. and the moving speed of water at 40 ° C. of the obtained membrane were 100, 120 and 20 respectively.
0Ω · cm, water movement speed 2.40, 2.30, 2.00
It was g · cm / m ² · h · M.

Example 4 Of the film obtained in Example 1, the proportion of haloalkyl groups reacted with monoamine was 45 mol% and the ratio was 0.5 at 25 ° C.
A membrane with AC specific resistance in M sulfuric acid of 150 Ω · cm and water migration speed at 40 ° C of 1.80 g · cm / m ² · h · M was assembled in a cell, and 3 M sulfuric acid and a concentration of 30 g / liter were provided on one side. On the other hand, water containing iron ions was flowed in countercurrent at a rate of 2 liter / h per 1 m ² of the membrane effective area to recover the acid by the diffusion dialysis method. Acid recovery rate is 85%
The amount of waste liquid was 1.0 times and did not increase.

Example 5 Of the film obtained in Example 3, the proportion of haloalkyl groups reacted with monoamine was 32 mol%, and 0.5% at 25 ° C. was used.
A membrane with an AC specific resistance in M sulfuric acid of 200 Ω · cm and a water transfer rate of 2.00 g · cm / m ² · h · M at 40 ° C was assembled in a cell, and 3 M sulfuric acid and a concentration of 30 g / liter were provided on one side. On the other hand, water containing iron ions was allowed to flow countercurrently at a rate of 1.8 liter / h per 1 m ² of the membrane effective area to recover the acid by the diffusion dialysis method. Acid recovery rate is 8
At 5%, the amount of waste liquid did not increase by 1.0 times.

Example 6 (Comparative Example) 50 g of the chloromethylated copolymer obtained in Example 1 was added to N, N
Two batches of a 15% by weight solution dissolved in 300 ml each of dimethylformamide were prepared. 108 ml and 86 ml of 1N trimethylamine in N, N-dimethylformamide solution was slowly added dropwise with stirring under cooling at a temperature of 0 ° C., and then 53 g and 26 g of 2-methoxyethanol were added, and the ion exchange capacity was 2. 0 meq /
g dry resin solution D, 511 ml, 1.6 meq / g
462 ml of solution E of dry resin was obtained.

Each solution was cast into a film at 60 ° C. for 2 hours,
A film having a thickness of 50 μm was obtained. The obtained film was treated with 1N N, N,
A crosslinked film was obtained by immersing in a methanol solution of N′N′-tetramethyl-1,2-diaminoethane at 50 ° C. for 4 hours.
The proportions of haloalkyl groups reacted with monoamines in these films were 91 and 73 mol% for the solutions D and E, respectively. The specific resistance of AC of 0.5 M sulfuric acid at 25 ° C. and the moving speed of water at 40 ° C. of these films were 50 and 70 Ω · c, respectively.
m, water movement speed 4.00, 3.20 g · cm / m ² · h
・ It was M.

Example 7 (Comparative Example) In the film obtained in Example 6, the proportion of haloalkyl groups reacted with monoamine was 73 mol%, and 0.5 at 25 ° C.
An alternating current resistance in M sulfuric acid is 70 Ω · cm, and a moving speed of water at 40 ° C is 4.50 g · cm / m ² · h · M. On the other hand, water containing iron ions was flowed in countercurrent at a rate of 2 liter / h per 1 m ² of the membrane effective area to recover the acid by the diffusion dialysis method. 80% acid recovery
Therefore, the amount of waste liquid increased 1.2 times.

Example 8 In the film obtained in Example 2, the proportion of haloalkyl groups reacted with monoamine was 41 mol%, and 0.5 at 25 ° C. was used.
Membrane with AC specific resistance of 160 Ω · cm in M sulfuric acid and water migration speed of 2.00 g · cm / m ² · h · M at 40 ° C and hydrogen ion selective permeable membrane (Asahi Glass Co., Ltd., trade name Selemion HSV) Each of the 5 cells was alternately assembled in a cell, and a stock solution containing 1.8 M sulfuric acid and aluminum having a concentration of 15 g / liter was supplied to the selective permeation layer side of the hydrogen ion selective permeation membrane, and water was flown to the other side to form a unit. A voltage of 0.5 V per unit was applied and a current was passed at 0.05 A / cm to concentrate and recover sulfuric acid by electrodialysis. The solution is circulated from the tank so that the linear velocity is 5 cm / sec, and the stock solution is newly supplied at a rate of 2 liter / h per 1 m ² of the effective membrane area and 0.8 liter / h. Extraction was performed at a speed. On the water side, 0.6 l / h per 1 m ² of effective membrane area
Water was supplied at a rate of 1, and withdrawal was performed at a rate of 1.8 liters / hour. The current efficiency was 30% and the concentration concentration was 2.5M.

Example 9 (Comparative Example) In Example 8, in the film obtained in Example 6, the proportion of haloalkyl groups reacted with monoamine was 73 mol% and the temperature was 25 ° C.
AC resistivity in 0.5M sulfuric acid at 70 Ω · cm,
The movement speed of water at 40 ° C is 3.20 g · cm / m ^2.
-Sulfuric acid was concentrated and recovered in the same manner except that the h.M membrane was used. Current efficiency is as low as 15% and concentration is 1.9M
And was only slightly concentrated.

Example 10 In the film obtained in Example 3, the proportion of haloalkyl groups reacted with monoamine was 41 mol%, and 0.5 at 25 ° C. was used.
Membrane and cation-exchange membrane (trade name: Selemion CM, manufactured by Asahi Glass Co., Ltd.) having an AC specific resistance in M sulfuric acid of 160 Ω · cm and a moving speed of water at 40 ° C of 2.25 g · cm / m ² · h · M.
T) is placed between the anode and the cathode, the cell is kept at 60 ° C., 25% sodium sulfate aqueous solution is flown in the intermediate chamber, water is flown in the anode chamber and the cathode chamber, and a voltage of 5 V is applied between the electrodes. Electrolysis was performed. The solution is circulated from the tank so that the linear velocity is 5 cm / sec, the stock solution is a new stock solution supply at a rate of 2 liter / h per 1 m ² of effective membrane area, and the water is 1 m ² of effective membrane area. Was supplied at a rate of 0.5 liter / h. The sulfuric acid concentration obtained on the anode side was 15%.

Example 11 (Comparative Example) In Example 10, in the film obtained in Example 6, the proportion of haloalkyl groups reacted with monoamine was 91 mol% and 25
AC resistivity in 0.5M sulfuric acid at 50 ℃ is 50Ω ・ c
m, the moving speed of water at 40 ° C is 4.00 g · cm /
Electrolysis was performed in the same manner except that a m ² · h · M membrane and a cation exchange membrane (manufactured by Asahi Glass Co., Ltd., trade name Selemion CMT) were used. The sulfuric acid concentration obtained in the anode chamber was a low value of 5%.

Example 12 (Comparative Example) 50 g of each chloromethylated copolymer obtained in Example 1 was dissolved in 300 ml of N, N-dimethylformamide to prepare 1
A 5% by weight solution was prepared. Temperature 0 with stirring under cooling
27 ml of a 1N solution of trimethylamine in N, N-dimethylformamide was slowly added dropwise at 10 ° C., then 10
g of 2-methoxyethanol was added to obtain 387 ml of a solution F of an ion exchange capacity of 0.5 meq / g dry resin.

The solution F was cast at 60 ° C. for 2 hours to form a film having a thickness of 50 μm. The obtained film was treated with 1N N,
It was immersed in a methanol solution of N, N′N′-tetramethyl-1,3-diaminopropane at 50 ° C. for 24 hours to obtain a crosslinked film. The proportion of haloalkyl groups reacted with monoamines in these films was 23 mol%. In addition, 25 of this film
The AC specific resistance in 0.5 M sulfuric acid at 40 ° C. and the moving speed of water at 40 ° C. are a resistance value of 3200 Ω · cm and a moving speed of water of 0.2 g · cm / m ² · h · M, and the resistance is very high. It was a membrane.

Example 13 (Comparative Example) In Example 8, the proportion of haloalkyl groups reacted with the monoamine obtained in Example 12 was 23 mol%, and the alternating current specific resistance in 0.5 M sulfuric acid at 25 ° C. was 3200 Ω · cm. 40
The moving speed of water at ℃ is 0.2g · cm / m ² · h ·
Sulfuric acid was concentrated and recovered in the same manner except that the M membrane was used. In the case of this film, since the resistance was high, it was necessary to apply a high voltage of 1.2 V per unit in order to operate the film at 0.03 A / cm ² as in the case of Example 8.
The current efficiency was 30%, and the concentration concentration was 2.6M.

[0056]

EFFECT OF THE INVENTION The anion exchange membrane of the present invention has low resistance, high ion selectivity and corrosion resistance, and further has a low water transfer rate, so that the increase in the amount of waste liquid in the case of diffusion dialysis is small and the anion exchange membrane is low An improvement in concentrated concentration in dialysis and electrolysis is exhibited.

Front page continuation (72) Inventor Junjiro Iwamoto 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Central Research Laboratory, Asahi Glass Co., Ltd.

Claims (5)

[Claims] 1. A segment represented by the general formula (a) and a segment represented by the general formula (b), wherein m / n = 100.
An anion exchange membrane having a cross-linked structure in which a haloalkylated aromatic polysulfone-based block copolymer of / 1 to 1/10 is reacted with a monoamine and a polyamine. The ratio of the groups is 30 to 50 mol%, the AC specific resistance in 0.5 M sulfuric acid at 25 ° C. is 300 Ω · cm or less, and the sulfuric acid is passed from one side of the membrane to the other side when water is passed from the water side to the sulfuric acid side. Water moving speed is 3g ・ c at 40 ℃
Anion exchange membrane having m / m ² · h · M or less. Embedded image 2. The anion exchange membrane according to claim 1, wherein the polyamine is represented by the general formula (c). Embedded image 3. A solution containing an acid is brought into contact with one side of the anion exchange membrane, and water or an acid solution having a lower concentration than the opposite side is brought into contact with the other side of the anion exchange membrane to selectively diffuse the acid from the solution containing the acid. A method for recovering an acid using the anion exchange membrane according to claim 1 or 2 as the anion exchange membrane in recovering an acid to be dialyzed. 4. A cation exchange membrane or a hydrogen ion exchange membrane and an anion exchange membrane are alternately arranged between the cathode and the anode,
A method of recovering an electrolyte, wherein the anion exchange membrane according to claim 1 or 2 is used as the anion exchange membrane in the concentration and recovery of an electrolyte in which a voltage is applied and electrodialysis is performed while passing an electrolyte solution. 5. A cation exchange membrane on the cathode side and an anion exchange membrane on the anode side, or only an anion exchange membrane are arranged between the cathode and the anode, and a voltage is applied while passing a solution containing an electrolyte or an organic substance. An electrolysis method in which the anion exchange membrane according to claim 1 or 2 is used as the anion exchange membrane in an electrolysis reaction of applying and electrolyzing.