JPH0457370B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for desalting organic substances. Specifically, the present invention provides a simple desalination method for efficiently separating (removing) salts contained in organic substances with minimal leakage of organic substances in an electrodialysis tank configured by combining specified ion exchange membranes. It is. (Prior Art and its Problems) Generally, in the synthesis process of organic substances in the fields of foods, medicines, agricultural chemicals, etc., salts and the like are often produced as by-products. Furthermore, organic substances such as sugar solutions and fruit pulp extracts also contain a considerable amount of salts (ash). As means for separating salts contained in such organic substances, for example, a crystallization separation method and a method using an ion exchange resin or an ion exchange membrane have been proposed. Among these methods, the method using an ion exchange membrane is carried out in an electrodialysis tank in which a cation exchange membrane and an anion exchange membrane are arranged alternately between negative and positive electrodes to form a desalination chamber and a concentration chamber. be done. That is, by applying a DC voltage between the two electrodes while flowing a solution of an organic substance containing salts into the demineralization chamber of an ion exchange membrane electrodialysis tank and a solution containing an electrolyte, such as dilute saline solution, into the concentration chamber. The salts (ash) present in the solution of the organic matter pass through the ion exchange membrane as ions and move to the concentration side where they are desalted. Although this method of desalting salts contained in organic matter in an ion-exchange membrane electrodialysis tank is effective, at the same time, the organic matter tends to leak and is lost, and the cell voltage increases due to contamination of the membrane with the organic matter. Additionally, there are problems such as deterioration of the organic components and an increase in the number of times the membrane must be cleaned. In particular, for example, due to the difference in the concentration of organic matter between the demineralization chamber and the concentration chamber of an ion exchange membrane electrodialysis tank, the leakage caused by the diffusion of organic matter through the membrane is generally large, ranging from several to several tens of percent, and is a highly value-added product. In the case of organic matter, the loss is significant. As a measure to prevent the leakage of these organic substances, a method is generally used in which the pressure in the concentration chamber is higher than that in the demineralization chamber in an ion exchange membrane electrodialysis tank, but this method is far from perfect. Therefore, in order to reduce the loss of organic matter as much as possible, the solution in the concentration chamber that has been desalted in the ion-exchange membrane electrodialysis tank should be recycled again.
One possible method is to recover the leaked organic matter by subjecting it to desalination treatment. However, this method of recovering organic matter by repeatedly subjecting it to desalination treatment in an ion exchange membrane electrodialysis tank is extremely uneconomical and impractical in terms of equipment costs and running costs. (Means for Solving the Problems) In view of the above-mentioned problems, the present inventors conducted intensive research and used an ion-exchange membrane electrodialysis tank constructed by combining a cation-exchange membrane and an anion-exchange membrane, respectively. The inventors have discovered that by treating organic substances containing salts, the leakage of the organic substances can be minimized and desalination can be carried out efficiently, leading to the proposal of the present invention. That is, according to the present invention, a composite cation exchange membrane having an anion exchange membrane layer made of a polymer of a vinyl compound having a quaternary ammonium base and a vinylbenzyl group on at least one side, and a carbon number of 4 to 30 Anion exchange membranes in which one or more types of alkyl groups having a chain length of A method for desalting an organic substance is provided, which comprises electrodialyzing the organic substance. Organic substances containing salts to be subjected to the electrodialysis of the present invention generally include sugars such as fructose, glucose, sucrose, glucose, fructose, maltose, xylose, sutucarose, raffinose, and other oligosaccharides containing inorganic salts such as table salt. liquid, alcohols such as methanol, ethanol, propanol, glycerin, organic acids or their salts such as glycolic acid and gluconic acid, amino acids or their salts such as glutamic acid and glycic acid, vitamins, pulp such as plum extract, fish and shellfish, etc. extracts, other oligopeptides, antibiotics, coenzymes, food additives such as amines, pharmaceuticals, fragrances,
Biochemical substances, low-molecular compounds known as general chemical products, high-molecular polysaccharides such as starch, natural polymers such as various proteins, nucleic acids, enzymes, and water-soluble substances such as polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone. Synthetic polymers, etc. The concentration of salts contained in such organic substances is generally about 1 to 30%. In the present invention, it is necessary to perform desalination treatment in an electrodialysis tank composed of a combination of ion exchange membranes that specify organic substances including salts as described above, and the ion exchange membranes include an anion exchange membrane on at least one side. Composite cation exchange membrane with 4 to 30 carbon atoms
It is important to use an anion exchange membrane in which one or more types of alkyl groups having a chain length of That is, the composite cation exchange membrane (hereinafter also simply referred to as composite membrane) used in the present invention is not particularly limited as long as at least one side thereof is composed of the following anion exchange layer; It is preferable that the cation exchange membrane that is the substrate of the membrane has a high degree of crosslinking. Specifically, a composite cation exchange membrane in which a vinyl compound having a quaternary ammonium base and a vinylbenzyl group or a polymer thereof is present as an anion exchange layer on the surface of a cation exchange membrane substrate is particularly preferred. used. In addition, the term "quaternary ammonium bases" as used herein refers to not only quaternary ammonium bases, but also includes so-called onium bases such as quaternary pyridium bases, sulfonium bases, and phosphonium bases. . Further, the number of vinylbenzyl groups in the above vinyl compound may be one, two, or three or more. However, if there are too many vinylbenzyl groups in such a vinyl compound, polymerization tends to occur between or within the molecules of the vinyl compound, making it difficult to handle. 100 pieces is preferred. In addition, it is effective to have one or more quaternary ammonium bases in the vinyl compound, but if the number is too large, the effect of the present invention will not be exhibited, so it is generally 1 to 1000, particularly preferably 1 to 50. . The method for producing such a vinyl compound having a quaternary ammonium base and a vinylbenzyl group is not particularly limited, but it is generally synthesized, for example, by the following method. (1) Alkylating primary amines such as methylamine and ethylamine with vinylbenzyl chloride. (2) A divalent primary amine such as ethylene diamine or propylene diamine is reacted with vinylbenzyl chloride, and if necessary, converted to a quaternary ammonium base using an alkylating agent such as methyl iodide or dimethyl sulfate. (3) Tertiary amino compounds of trivalent or higher valence, e.g. (In the above formula, R ₁ : CH ₃ , CH ₃ CH ₃ , an integer of n1) and the like with at least one vinylbenzyl chloride. Furthermore, if necessary, unreacted tertiary amino groups may be converted to quaternary amino groups using another alkylating agent. (4) Compounds having one or more halogen atoms in the same molecule, for example, etc. are reacted with vinylphenylalkyl N,N-dialkylamine. These reaction conditions may be carried out without a solvent, or in any concentration of water, alcohol, acetone, dimethylformamide, dimethyl sulfoxide, benzene, chloroform, or any combination thereof with stirring, and the reaction temperature is generally 0 to 100°C. ℃,
A temperature range of 5 to 80°C can be suitably employed. Moreover, it is generally preferable that the reaction is carried out in the presence of a radical polymerization inhibitor such as hydroquinone. The method for producing the vinyl compound polymer described above is as follows:
There is no particular limitation, and any known method may be used, such as radical polymerization, cationic polymerization, or the like. That is, a predetermined vinyl compound is prepared without a solvent, in water, an aqueous solution of an inorganic salt, or in a single or mixed solvent such as an organic solvent such as methanol or ethanol, preferably 0.1 to 4.0N, particularly preferably 0.2N to 2.0N common salt. Polymerization may be carried out by adding a radical polymerization initiator or a cationic polymerization initiator in water. Examples of initiators for radical polymerization include peroxides such as acetyl peroxide, benzoyl peroxide, lauroyl peroxide, potassium peroxodisulfate, ammonium peroxodisulfate, t-butyl hydroperoxide, and hydrogen peroxide; Azo compounds such as nitrile, azobis-2-amidinopropane, hydrochloride; furthermore, hydrogen peroxide-ammonia, ethylamine, Fe() salt, etc.; peroxodisulfate-sodium sulfite, sodium bisulfite, triethanolamine,
Redox initiators such as Fe() salt and the like; sodium perchlorate-sodium sulfite; and the like are also preferably used. Alternatively, ionizing radiation may be irradiated. Furthermore, as initiators for cationic polymerization, metal halides such as aluminum chloride, zinc chloride, stannic chloride, titanium chloride, boron trifluoride, and antimony pentachloride; phosphoric acid, sulfuric acid, chlorosulfonic acid, perchloric acid, protonic acids such as; organometallic compounds such as triethylaluminum, etc. are used. Any conditions may be used for the polymerization of the vinyl compound, but generally the polymerization may be carried out at a temperature below the decomposition temperature of the vinyl compound or below the boiling point of the solvent used. In addition, the polymerization time varies depending on the type of catalyst used, polymerization temperature, etc., and cannot be absolutely limited, but generally it is about 5 minutes to 10 hours when using a redox polymerization initiator, and when using a radical polymerization initiator. It is preferable to select from the range of about 3 hours to 3 days. In the composite cation exchange membrane of the present invention, the amount of the above vinyl compound or its polymer present on the surface of the cation exchange membrane varies depending on the type, charge, etc. of the cation exchange membrane, but generally
0.001mg/ ^cm2 or more and less than 1/2 of the cation exchange membrane layer,
Particularly preferred is 1/3 or less. The cation exchange membrane that is the base of the composite membrane in the present invention is not particularly limited, but generally other monomers that can be copolymerized with a monomer having a cation exchange group or a functional group suitable for introducing a cation exchange group,
It is obtained by polymerizing a copolymerization monomer for forming crosslinks, a plasticizer, a polymerization catalyst, and if necessary a finely powdered thermoplastic polymer substance as a reinforcing material, a base material, etc. by a known method. Examples of the above cation exchange groups include:
Sulfonic acid group, carboxylic acid group, phosphonic acid group, sulfuric acid ester group, phosphoric acid ester group, thiol group,
Examples of monomers with active groups that can form chelate structures with heavy metals and functional groups suitable for introducing ion exchange groups include styrene, styrene sulfonic acid derivatives, vinyl sulfonic acid derivatives,
Acrylic acid ester, maleic anhydride, etc.
Examples of copolymerizable monomers include aromatic vinyl monomers such as chloromethylstyrene, vinyl monomers such as acrylonitrile, and the like. Examples of copolymerizable monomers (crosslinking agents) that form crosslinks include divinylbenzenes, trivinylcyclohexanes, ethylene glycol dimethacrylates, divinylnaphthalene, divinyltoluene, and propylene glycol diacrylates. Furthermore, examples of plasticizers include dioctyl phthalate and dibutyl phthalate, and examples of polymerization catalysts include benzoyl peroxide, azoisobutyronitrile, and dicumyl peroxide. The degree of crosslinking in the cation exchange membrane of the present invention is generally as high as 10 to 50%, preferably 15 to 30%, based on the proportion of crosslinking agent added, in order to achieve good desalination of organic acids in the present invention. extremely effective in achieving this. That is,
If the above degree of crosslinking is less than 10%, the leakage of organic substances will increase due to increased swelling and contraction of the membrane.
This is not preferred in the organic acid desalting treatment of the present invention, and if the degree of crosslinking is 50% or more, the electrical resistance of the membrane increases, which is not preferred. The above-mentioned cation exchange membrane may be in a water-containing state or in an anhydrous state, but is usually used in a water-containing state. Further, the cation exchange group of the cation exchange membrane may be of a hydrogen type or a salt type, and salts, acids, bases, and other substances may be contained in the cation exchange membrane. In the composite membrane of the present invention, the method for making the vinyl compound or the polymer of the vinyl compound exist on at least one surface of the cation exchange membrane is not particularly limited, and any known method can be adopted as is. . The typical method generally used industrially is
For example, the following method is available. For example, the above-mentioned vinyl compound or a polymer of the vinyl compound may be coated or sprayed on one or both sides of the cation exchange membrane as it is or dissolved or dispersed in an appropriate solvent. Alternatively, a method may be adopted in which the cation exchange membrane is immersed in a solution containing a vinyl compound or a polymer of the vinyl compound, and if necessary, excess adhering vinyl compound or polymer of the vinyl compound is removed. . Furthermore, after cation exchange membranes and anion exchange membranes are installed alternately in an electrodialysis tank as required, the vinyl compound or the polymer of the vinyl compound is heated with or without electricity. It is also possible to adopt a means of circulating a solution containing. Furthermore, the means for making the polymer of the vinyl compound exist on at least one surface of the cation exchange membrane includes making the vinyl compound exist on at least one surface of the cation exchange membrane, and then polymerizing the vinyl compound. A means to do so can be suitably adopted. As a means for such polymerization, generally, the vinyl compound can be polymerized by bringing a cation exchange membrane, on which the vinyl compound is present on at least one surface, into contact with a solution containing a polymerization initiator. Depending on the type of polymerization initiator used, a solution containing a vinyl compound and a polymerization initiator may be present on at least one surface of the cation exchange membrane at a low temperature, and the vinyl may be removed by increasing the temperature. It is also possible to employ means for polymerizing the compound. Alternatively, a method may be used in which the vinyl compound is present on both sides of the cation exchange membrane and then only one side is brought into contact with the polymerization initiator.
Incidentally, the polymerization of the vinyl compound described above is preferably carried out under a nitrogen atmosphere in any case. On the other hand, the anion exchange membrane of the present invention has at least 6 to 30 carbon atoms in the anion exchange group present in the surface layer.
An anion exchange membrane to which one or more types of alkyl groups having a chain length of is bonded is used. One alkyl group having a chain length of 6 to 30 carbon atoms is added to the above anion exchange group.
The type of compound (hereinafter referred to as a long-chain alkylating agent) that can be combined with more than one species cannot be unconditionally determined because it is naturally determined by the constituent components of the ion exchange membrane. For example, in the case of vinylpyridine-based anion exchange membranes, long-chain alkyl halides are used, and in the case of haloalkyl group-based anion exchange membranes, long-chain alkylamines and trialkylstibines having at least one long-chain alkyl group are used. , trialkylphosphine, etc. are used. Generally, linear alkylating agents are more effective as these long-chain alkylating agents, but they do not necessarily have to be linear, and branched alkylating agents are also effective to varying degrees. Further, a portion may be substituted with a relatively inert halogen or the like. Such long-chain alkylating agents preferably have 4 to 30 carbon atoms; if the chain has more than 4 carbon atoms, the reactivity will be significantly poor; on the other hand, if the number of carbon atoms is less than 4, In this case, the leakage of the organic matter becomes large in the desalination treatment of the organic matter of the present invention. The reactivity of the alkylating agent varies depending on the degree of crosslinking of the polymer membrane used, but in the case of styrene-divinylbenzene-vinylpyridine-based membranes and styrene-divinylbenzene-haloalkylstyrene-based membranes, the degree of crosslinking of the membrane is high. As the temperature increases, only the surface layer of the membrane will react. Particularly preferred alkylating agents are compounds having a chain length of 8 to 20 carbon atoms;
The particularly effective action of the above alkyl groups seems to be correlated with the micelle formation phenomenon observed in surfactants. That is, as is well known from the past, when the number of carbon atoms exceeds 8, micelles are observed to be formed in the surfactant solution. Therefore, it is possible that intramembrane micelles are formed near the anion exchange group in the present invention as well. Typical manufacturing methods for the anion exchange membrane used in the present invention are as follows: (1) Styrene-divinylbenzene-vinylpyridine is made viscous by adding styrene-butadiene rubber, etc., and a radical polymerization initiator is added to form a polychloride. It is applied to a cloth such as vinyl, then heat-polymerized to form a film, and then alkylated with a long-chain alkyl halide such as dodecyl bromide, followed by a short-chain alkyl halide such as methyl iodide if necessary. How to react with. (2) A radical polymerization initiator is added to a monomer mixture of styrene-divinylbenzene-chloromethylstyrene and fine powder such as polyvinyl chloride, and the same is applied to a cloth-like material, polymerized by heating, and reacts with, for example, dioctylamine. A method of reacting with trioctylamine, etc., if necessary. (3) A method in which fine powder of polyvinyl chloride is heated with dimethyldodecylamine to cause the polyvinyl chloride and tertiary amine to react, and then heated and formed into a film. (4) Other methods include reacting lauryl bromide with a conventionally known anion exchange membrane obtained by reacting dimethylamine with a polymer membrane synthesized mainly of chloromethylstyrene-divinylbenzene-styrene. In addition, after reacting a polymer film having the same halomethyl group with trimethylamine, oxidation, heat treatment, etc.
A method of partially or completely decomposing a class ammonium base to convert it into a tertiary, secondary, or primary amino group and then reacting it with stearyl bromide or the like is adopted. Generally, from the viewpoint of obtaining a membrane with a high fixed ion concentration, a homogeneous ion exchange membrane is more desirable than a heterogeneous ion exchange membrane. The base material of the anion exchange membrane can be anion exchange membranes made by any of the methods proposed in the past, and as long as they have the anion exchange groups specified in the present invention, fixed ions can be used. It becomes a high-performance anion exchange membrane with high concentration. In addition, the amount of long-chain alkylating agent, such as long-chain alkyl halide or long-chain alkylamine, depends on its type, reaction conditions, chain length of alkyl group, reaction activity of halogen and amine, and the shape of the polymer film to be reacted. Although it varies depending on the substance, the type and structure of the polymer, the activity of the reaction site, etc., and the purpose of use of the obtained anion exchange membrane.
As the reaction amount of the long-chain alkylating agent increases, the fixed ion concentration in the membrane increases, and at the same time, the electrical resistance of the ion exchange membrane also increases. Furthermore, in order to increase the Donnan exclusion effect of the anion exchange membrane, it is effective to increase the concentration of fixed ions in the membrane at the membrane-liquid interface in contact with the solution. For this reason, as a result of examining the amount of various long-chain alkylating agents to be reacted, it was found that the alkylating agent is present in at least one of the membrane surface layers, and that the amount is approximately 20% of the total ion exchange capacity of the membrane. % or more of anion exchange groups. Furthermore, if necessary, for example, in the case of an anion exchange membrane containing vinylpyridine as one component, the remaining anion exchange group is a tertiary amino group based on the pyridine group, which can be anionic if used in an acidic atmosphere. It acts as an ion exchange group, but becomes inactive when used in a neutral or alkaline atmosphere. Therefore, a type of alkylating agent such as an alkyl halide that can easily react within a polymer matrix with a short carbon chain length such as methyl iodide, methyl bromide, ethyl iodide, ethyl bromide, dimethyl sulfate, etc. By reacting with the above, a polymer film having quaternary ammonium bases as most of the anion exchange groups can be obtained. In addition, when reacting something like dodecylamine to a polymer film such as chloromethylstyrene-styrene-divinylbenzene, it is necessary to A layer that cannot be completely reacted and has no electrical conductivity, that is, there is no anion exchange group, is formed inside the membrane or on the back side when only one side is reacted. Since such substances cannot actually be used, methylamine, dimethylamine, trimethylamine, trimethylstibine,
By reacting a compound with a short alkyl chain length such as trimethylphosphine, trimethylarsine, or triethylamine with the chloromethyl group present inside the polymeric membrane, it becomes able to function as an anion exchange membrane. The electrodialysis tank used in the present invention has a basic structure in which the above-specified composite cation exchange membrane and anion exchange membrane are arranged between the anode and the cathode, and the known electrodialysis tank has particular limitations. used without. For example, a three-chamber type in which a specific composite membrane and an anion exchange membrane are each installed between the anode and cathode, a composite membrane and an anion exchange membrane are alternately arranged between the electrodes via a chamber frame, These include a filter press type and a unit cell type, which have a basic structure in which a demineralization chamber and a concentration chamber are formed by both ion exchange membranes and a chamber frame. The number of membranes used in such an electrodialysis tank, the channel spacing (membrane spacing) between the demineralization chamber and the concentration chamber, etc. are appropriately selected depending on the type of organic matter to be treated and the amount to be treated. Additionally, the anion exchange tank of the composite membrane is generally placed in close contact with the organic matter. The method for removing salts from organic substances using the above-mentioned electrodialysis tank of the present invention is to supply the above-mentioned organic substances to the demineralization chamber of the electrodialysis tank, water or electrolyte solution to the concentration chamber, and further supply the cathode and anode electrodes. This is carried out by passing a direct current between the anode and the cathode while supplying an electrode solution made of an electrolyte solution such as saline to the chamber. That is, in the present invention, by applying electricity in the above state, salts in the organic matter supplied to the demineralization chamber, for example, sodium ions (Na ⁺ ) and chloride ions (Cl ^- ) of common salt, pass through the membrane and are concentrated. Since it is discharged into the room, it decreases over time. On the other hand, in the present invention, ions in the organic matter should also be discharged to the concentration side (electrode chamber side) as Na ⁺ and Cl ^- in the salt move, but since the above-mentioned specific ion exchange membrane is used,
These ions account for 1 to 2% at most, and exhibit a phenomenon in which they are extremely difficult to penetrate. In such electrodialysis, the voltage, current density, and treatment time applied to the electrodialysis tank are appropriately selected depending on the concentration of salts to be removed. (Functions and Effects) As explained above, according to the desalination method of the present invention, organic substances including salts can be easily supplied by electrodialysis tanks each having a combination of specific ion exchange membranes. Salts can be removed efficiently with very little leakage.
Although the reason why the present invention exhibits such effects is not necessarily clear, the characteristics of the predetermined composite cation exchange membrane and anion exchange membrane used in the electrodialysis tank of the present invention, respectively, are effective in desalting organic matter. It is recognized that it is working extremely effectively. That is, the composite ion exchange membrane used in the present invention has an extremely dense structure in all layers, and since the vinyl group of the vinyl compound in the anion exchange layer is styrene-based, it is mechanically and chemically strong. Since a vinyl compound or a polymer of a vinyl compound with an opposite charge to the cation exchange group of the cation exchange membrane is more strongly present, less charged cations are selectively permeated from the electrolyte solution containing cations. Further, the property of resisting organic contamination may be imparted by the unique structure of the composite ion exchange membrane used in the present invention. Furthermore, the anion exchange membrane having a long-chain alkyl group used in combination also has good selectivity and resistance to organic contamination due to its unique structure. (Examples) Examples for specifically explaining the present invention will be shown below, but the present invention is not particularly limited to these Examples. In the following Examples and Comparative Examples, the desalination and performance of organic compounds containing salts were evaluated using a multi-chamber electrical system in which the composite ion exchange membrane and anion exchange membrane of the sample were arranged alternately between the anode and cathode and tightened. The test was carried out using a dialysis tank (effective membrane area 2 dm ² ). Moreover, "parts" indicate parts by weight. Example 1 Composite cation exchange membrane A 100 parts of styrene, 30 parts of divinylbenzene with a purity of about 80%, 10 parts of chloromethylstyrene, 20 parts of dioctyl hetalate, and 50 parts of polyvinyl chloride fine powder mixed with 3 parts of benzoyl peroxide. The resulting paste mixture was applied to a polyvinyl chloride cloth, degassed, and both sides covered with cellophane.
Polymerization was carried out by heating at ℃ for 4 hours to obtain a crosslinked polymer film.
This was immersed in a 1:1 mixture of chlorosulfonic acid and sulfuric acid at 40°C for 60 minutes to obtain a cation exchange membrane. Note that the degree of crosslinking of the cation exchange membrane is 25%. Next, 0.1 mol of N,N,N',N',N''-pentamethyliminobispropylamine and 0.3 mol of chloromethylstyrene were added to 200 ml of methanol at room temperature.
The reaction was carried out for 48 hours to obtain a compound having three quaternary ammonium groups and three vinylbenzine groups. The above cation exchange membrane was immersed in a 1.0N-NaCl solution containing 2000 ppm of this compound at 40°C for 2 hours, and then 1500 ppm each of potassium persulfate and sodium sulfite were added as polymerization initiators under a nitrogen atmosphere.
The liquid was stirred vigorously. After 10 hours, the composite ion exchange membrane (A) was taken out. Anion Exchange Membrane A A paste mixture consisting of 160 parts of 4-vinylpyridine, 10 parts of styrene, 15 parts of divinylbenzene with a purity of about 55%, 25 parts of dioctyl phthalate, 100 parts of polyvinyl chloride fine powder, and 3 parts of benzoyl peroxide. The mixture was applied to a plain woven polyvinyl chloride cloth, both sides of which were covered with polyvinyl alcohol sheets, and polymerized by heating at 90° C. for 4 hours to obtain a polymer film. This membrane was left immersed in dodecyl bromide and n-heptane at 45°C for 2 months. Next, it was taken out and thoroughly washed in n-heptane, and then further washed with methanol to obtain an anion exchange membrane (A). Combined cation exchange membrane A and anion exchange membrane A are assembled into an electrodialysis tank, and sutucarose is placed in the desalination chamber.
An aqueous solution containing 1 mol/ml of salt and 0.3 mol/ml of common salt was supplied, water was supplied to the concentration chamber, and dialysis was performed by passing current at a current density of 1 A/dm ² . As a result, the desalination rate was 98% and the sutucarose leak rate was 2%. Comparative Example 1 Example 1 except that a cation exchange membrane in which a cation exchange group was simply introduced into the crosslinked polymer membrane obtained in Example 1 and Neocepta "AM" manufactured by Tokuyama Soda as an anion exchange membrane were used. I did the same thing. As a result, the salt removal rate was 89% and the leakage rate was 35%. Example 2 and Comparative Example 2 Sutucarose 1 mol/ and salt 0.3 mol/
and sodium dodecylbenzenesulfonate
Example 1 by supplying an aqueous solution containing 0.1 mol/
Electrodialysis was performed in the same manner. The results are shown in Table 1.

[Table] Example 3 and Comparative Example 3 1 mol of vitamin B/and salt in the desalination room
The same procedure as in Example 2 was carried out except that an aqueous solution containing 0.5 mol/l was supplied. The results are shown in Table 2.

[Table] Example 4 Composite cation exchange membrane B 100 parts of styrene, 50 parts of divinylbenzene with a purity of about 55%, 10 parts of chloromethylstyrene, 20 parts of acrylonitrile, 20 parts of dibutyl phthalate, 20 parts of acrylonitrile-butadiene rubber, polychloride A paste mixture obtained by mixing 10 parts of vinyl fine powder and 3 parts of benzoyl peroxide was applied to a polyvinyl chloride cloth, degassed, covered with polyester film on both sides, and polymerized by heating at 80°C for 7 hours. A polymer membrane was obtained. This was immersed in a 1:1 mixture of chlorosulfonic acid and sulfuric acid at 40°C for 60 minutes to obtain a cation exchange membrane. Note that the degree of crosslinking of the cation exchange membrane is 30%. Next, dimethylarylamine was polymerized to obtain 8.5g (0.1mol) of tertiary polyamine with an average molecular weight of 1000.
Dissolve in 200ml of methanol, add 15.3g (0.1mol) of chloromethylstyrene, and react at 40℃ for 3 days to quaternize the tertiary polyamine and
Ten vinylbenzyl groups were introduced. The cation exchange membrane was immersed in a 0.5 N aqueous sodium sulfate solution containing 3000 ppm of this substance at 50°C for 6 hours, and then azobis-
Add 3000 ppm of 2-aminodipropane hydrochloride,
Polymerization was carried out for 15 hours to obtain a composite ion exchange membrane (B) of the present invention. Anion exchange membrane B: Add 160 parts of chloromethylstyrene, 40 parts of divinylbenzene with a purity of about 55%, 10 parts of acrylonitrile rubber, and 6 parts of benzoyl peroxide, mix and dissolve uniformly, and then add this to a plain-woven polyvinyl chloride membrane. Apply to cloth, deaerate, cover both sides with polyvinyl alcohol sheets, and place in an autoclave at 90℃.
The mixture was heated for 8 hours to polymerize and form a polymer film. This was combined with dioctylamine (100%) at 60°C for 24 min.
After reacting for a period of time, the membrane was thoroughly washed with methanol to obtain an anion exchange membrane (B). Dialysis was carried out under the same conditions as in Example 1 in an electrodialysis tank using composite ion exchange membrane B and anion exchange membrane B. In addition, the membrane used for comparison was Comparative Example 1.
The same membrane was used. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1 A composite cation exchange membrane having an anion exchange layer made of a polymer of a vinyl compound having a quaternary ammonium base and a vinylbenzyl group on at least one side is bonded to one or more types of alkyl groups having 4 to 30 carbon atoms. The method is characterized in that an electrodialysis tank is constructed by alternately arranging anion exchange membranes having anion exchange groups between electrodes, and an organic substance containing salts is supplied to the desalting chamber for electrodialysis. A method for desalinating organic matter.