JP4944536B2 - Electrolyte separation apparatus and electrolyte separation method - Google Patents

Description

  The present invention relates to an electrolyte separation apparatus and an electrolyte separation method useful for desalting in industries such as the chemical industry, electronics / electric industry, fermentation industry, food industry, biological industry, pharmaceutical industry, and seawater desalination.

  A mosaic charged membrane in which a cationic polymer and an anionic polymer penetrate from the membrane surface to the back surface and are in contact with each other can pass a low molecular weight electrolyte, but a non-electrolyte is difficult to permeate. For example, there is great expectation for desalination in biochemical-related fields, or desalination of seawater and the like, and various studies have been made.

  As a method for producing a mosaic charged membrane, a method using phase separation of a block copolymer has been proposed, but its production such as difficulty of synthesis of the block copolymer itself and introduction of ionic groups has been proposed. The method was very cumbersome, the production of large membranes was difficult and very expensive. On the other hand, a method for producing a mosaic charged membrane by accumulating fine particles of a cationic polymer and an anionic polymer as an element has been proposed. Since the mosaic charged film is formed by a coating method, a large film can be easily obtained, and its industrial use has been studied.

  The diffusion dialysis method that separates the electrolyte by providing a difference in electrolyte concentration between the stock solution chamber side and the dialysate chamber side using a mosaic charged membrane requires a long time for separation, and further, calcium ions, aluminum ions, Separation of electrolytes composed of multivalent ions such as sulfate ions and phosphate ions has a problem that it takes longer time than electrolytes composed of monovalent ions such as sodium ions and chlorine ions.

  An object of the present invention is to efficiently separate an electrolyte when separating an electrolyte from a solution containing an electrolyte and a non-electrolyte, and further to an electrolyte separation device having an effect for separating an electrolyte composed of multivalent ions, and It is to provide a method for separating electrolytes.

The above object is achieved by the present invention described below. That is, the present invention relates to an electrolyte separator used for separating the electrolyte from an electrolyte solution containing a polyvalent ion-containing electrolyte and a non-electrolyte, wherein the stock solution chamber and the dialysis solution chamber are ion-permeable membranes. An electrolyte separation apparatus comprising an AC electrode chamber having an AC electrode into which an electrolyte solution is introduced inside the dialysis tank on the outermost side of the dialysis tank; and An electrolyte separation method using a separation device is provided.

  In the electrolyte separation device of the present invention, the ion permeable membrane is preferably a mosaic charged membrane comprising a cationic polymer, an anionic polymer, and a matrix that are at least partially crosslinked granular polymers. In the electrolyte separation method of the present invention, it is preferable to pressurize the stock solution chamber during the separation of the electrolyte.

  The stock solution chamber and the dialysate chamber are composed of a pair of or alternately arranged dialysis tanks with an ion permeable membrane sandwiched between them, and the dialysis tank is preferably provided with an electrolyte separator having AC electrodes in at least two places. By applying an alternating electric field to the stock solution, dialysate and / or membrane, it is possible to relieve a large concentration gradient of the electrolyte (ions) in the vicinity of the membrane, and to move ions quickly to the membrane surface. The movement of ions from the membrane surface to the dialysate chamber is promoted, so that not only electrolytes composed of monovalent ions but also electrolytes composed of multivalent ions can be efficiently separated.

Hereinafter, the present invention will be described in more detail with reference to the best mode for carrying out the invention.
In the electrolyte separation apparatus and separation method of the present invention, the electrolyte is separated by creating a concentration difference of the electrolyte (salt) between the stock solution side and the dialysate side. Since the mosaic charged membrane used in the present invention has many ion-permeable channels built in the membrane, even if the electrolyte concentration is several hundred ppm or less, if there is a difference in electrolyte concentration between the stock solution side and the dialysate side, It has the feature that dialysis of electrolyte is possible. Therefore, an excellent desalting effect is exhibited not only when the concentration of the electrolyte in the stock solution is high, but also in the case of a stock solution (raw water) having a low electrolyte concentration of 1% by mass or less.

  The mosaic charged film used in the present invention is a film already proposed by the present applicant. For example, Japanese Patent No. 2618852, Japanese Patent No. 2895705, Japanese Patent No. 3012153, Japanese Patent No. 3016406, Japanese Patent No. 3156955. No. 3,234,426, No. 3,236,754, No. 3,453,056, No. 3,453,067, and No. 3,626,650 are all used in the apparatus of the present invention. be able to.

  The separation device of the present invention comprises a dialysis tank in which a stock solution chamber and a dialysis solution chamber are arranged in pairs or alternately with an ion-permeable membrane interposed therebetween, and the dialysis tank preferably has AC electrodes at at least two locations. The separation method of the present invention is characterized in that an alternating electric field is applied to raw water (salt water), dialysate and / or using the apparatus.

  An example of the configuration of the separation apparatus of the present invention will be described with reference to FIG. The device is alternately arranged with a mosaic charged membrane in which the stock solution chamber and dialysate chamber are arranged as an ion permeable membrane. The treated solution (stock solution) flows into the stock solution chamber and the treated solution (desalted water) is discharged. Dissolved ions in the liquid to be treated that flow into the stock solution chamber by installing a flow channel for dialysate inflow and salt water discharge into the dialysate chamber and applying an alternating electric field of a predetermined voltage and frequency. Is a device that permeates the dialysate chamber. At this time, it is desirable to sandwich a mesh-like material between the stock solution chamber and the dialysate chamber in order to prevent a short circuit between the liquid to be treated and the dialysate. The mosaic charged membrane disposed as an ion permeable membrane is a membrane made of a cationic polymer, an anionic polymer and a matrix, which are at least partially crosslinked granular polymers, and reinforced with a woven support.

  As an alternating electric field to be applied, the voltage is in the range of 0.01 V / cm to 1 kV / cm, more preferably in the range of 0.1 V / cm to 100 V / cm. The frequency is in the range of 10 Hz to 10 MHz, more preferably in the range of 100 Hz to 1 MHz.

  In addition, the AC electrodes are preferably installed in at least two locations in the stock solution chamber and the dialysate chamber, which are arranged in pairs or alternately with the ion-permeable membrane interposed therebetween. In addition, when pure water is used as dialysis water, electrical resistance increases and heat is easily generated. Therefore, an AC electrode chamber is installed on the outermost side of the stock solution chamber and the dialysis solution chamber, and an electrolyte solution is introduced into the electrode chamber. It is desirable to apply an alternating electric field.

  By applying an alternating electric field to the undiluted solution, dialysate and / or membrane using the separation device equipped with the above-mentioned alternating current electrode, the large concentration gradient of ions (salts) in the vicinity of the membrane is alleviated, and the ions are transferred to the membrane surface. It is possible to move quickly. In addition, polyvalent ions such as calcium ions, aluminum ions, sulfate ions, and phosphate ions are more electrically connected to monovalent ions such as sodium ions and chloride ions from the fixed charges of the membrane that are received when passing through the membrane. The permeation rate is small because of the large constraints. In the present invention, by applying an alternating electric field to the stock solution, dialysate and / or the membrane to vibrate the bond between the fixed charge of the membrane and the ions, the electrical binding from the fixed charge of the ion membrane is weakened, Since the permeation of ions is performed quickly, permeation of not only monovalent ions from the membrane surface of the stock solution chamber to the dialysate chamber but also multivalent ions is promoted, and desalting efficiency can be improved.

  Also, in the pressure dialysis method in which the separation chamber of the present invention comprising an AC electrode and a pair of undiluted solution chamber and dialysis solution chamber sandwiching a mosaic charged membrane is used to pressurize the undiluted solution chamber, ion permeation by pressurization In addition, the ion transmission effect by application of an alternating electric field is further promoted.

  The desalting apparatus of the present invention is suitable for desalting in industries such as the chemical industry, the electronics / electric industry, the fermentation industry, the food industry, the biological industry, the pharmaceutical industry, and the desalination of seawater, specifically, proteins, amino acids, etc. It can be applied to a wide range of applications such as desalination of dyes, pigments, surfactants, etc., and desalting in fields where electrodialysis has not been applied due to alteration of target substances due to heat generation and membrane contamination due to ion adsorption. .

  The separation apparatus equipped with an AC electrode of the present invention can recover an acid or the like by using an anion exchange membrane as an ion permeable membrane, or an amine or the like by using a cation exchange membrane as an ion permeable membrane. Is also useful.

Next, the present invention will be described more specifically with reference to reference examples, examples and comparative examples. In the text, “part” and “%” are based on mass unless otherwise specified.
Reference Example 1 (Polymer A: Synthesis of Cationic Granular Polymer)
・ 2-vinylpyridine 20.0 parts ・ Divinylbenzene 2.0 parts ・ 2,2-azobis (2-amidinopropane) dihydrochloride
0.4 parts, 1,000 parts of water

  The above components were charged into a flask and polymerized at 80 ° C. for 8 hours under a nitrogen stream. The polymerization product was freeze-dried to obtain a granular polymer having an internally crosslinked structure. The average particle size of the granular polymer was about 350 nm as measured with a scanning electron microscope.

Reference Example 2 (Polymer B: Synthesis of Anionic Granular Polymer)
-Styrene 41.6 parts-Acrylonitrile 7.1 parts-Hydroxyethyl methacrylate 8.1 parts-Divinylbenzene 8.7 parts-Potassium persulfate 0.5 parts-Water 1,000 parts

  The above components were charged into a flask and polymerized at 80 ° C. for 8 hours under a nitrogen stream. The average particle diameter of the obtained polymer was about 180 nm. The granular polymer was separated by filtration, dried and pulverized to obtain a granular polymer. 100 parts of this granular polymer was gradually added to 650 parts of 98% concentrated sulfuric acid and stirred at 50 ° C. for 24 hours and then at 80 ° C. for 3 hours. Then, it cooled and thrown the reaction liquid mixture into a lot of ice water. After neutralizing with sodium carbonate, the particulate polymer was separated by filtration and washed thoroughly with water. The obtained granular polymer was confirmed to have almost one sulfonic acid group introduced into the aromatic ring by analysis such as infrared absorption spectrum and ion chromatography. The average particle diameter of this granular polymer was about 240 nm.

Reference Example 3 (Mosaic charged film production)
2.0 parts of polymer A was dispersed in 8.0 parts of N-methyl-2-pyrrolidone. This dispersion was mixed with 66.7 parts of a 10% N-methyl-2-pyrrolidone solution of polysulfone resin for 1 hour. Further, 4.7 parts of this dispersion, polymer B, and 18.7 N-methyl-2-pyrrolidone were mixed. The coating liquid was prepared by mixing the liquid dispersion consisting of the parts and defoaming. The coating solution was applied onto a polypropylene resin-coated release paper with a knife coater, a polyester woven fabric was pressure-bonded, and dried with hot air. Next, after leaving it in an iodomethane atmosphere at room temperature for 12 hours, it was washed with water and air-dried to prepare a mosaic charged film. The mosaic charged film produced by the above method had a thickness of about 210 μm and a uniform thickness.

Reference example 4
19 mosaic charged membranes (membrane area 135 cm ² ) obtained in Reference Example 3 were arranged at intervals of 2 mm so as to alternately form a stock solution chamber and a dialysate chamber. Using a separation apparatus having a stock solution chamber and a dialysate chamber configured as described above and having an AC electrode chamber at both ends, a 1.0 mol / L sodium chloride aqueous solution (electric conductivity 58.3 ms / cm) was used as a stock solution. ) The concentration of the stock solution was 0.01 mol / L (electric conductivity 1.10 ms / min) under the conditions of 1000 ml, deionized water as dialysate, flow rate 1 L / min, distance between electrodes 5 cm, voltage 10 V, frequency 100 Hz. The stock solution was desalted and purified until it reached cm), and the results are summarized in Table 1. At that time, the stock solution was circulated and the dialysate was recovered as salt water in one pass.

Comparative Example 1
The separation of the stock solution was performed in the same manner as in Reference Example 4 except that a separation apparatus consisting of a stock solution chamber and a dialysate chamber sandwiching a mosaic charged membrane was used, and the results were summarized in Table 1. According to Table 1, the permeation rate of sodium chloride in Reference Example 4 was increased 1.07 times that of Comparative Example 1 by applying an alternating electric field.

Example 2
In a similar manner, except for using the aqueous solution of calcium chloride 1.0 mol / L in place of aqueous sodium chloride solution of Reference Example 4 (electric conductivity 120.3ms / cm) as in Reference Example 4, the concentration of the stock solution 0.01mol The stock solution was separated and purified until / L (electric conductivity 2.18 ms / cm), and the results are summarized in Table 1.

Comparative Example 2
The separation of the stock solution was carried out in the same manner as in Example 2 except that a separation apparatus comprising a stock solution chamber and a dialysate chamber sandwiching a mosaic charged membrane was used without providing an AC electrode, and the results are summarized in Table 1. According to Table 1, the permeation rate of calcium chloride of Example 2 is 1.45 times greater than that of Comparative Example 2 by applying an alternating electric field, and the permeation rate of calcium chloride is as large as sodium chloride. Became.

Example 3
In a similar manner, except for using the aluminum chloride aqueous solution 1.0 mol / L in place of aqueous sodium chloride solution of Reference Example 4 (electric conductivity 117.2ms / cm) as in Reference Example 4, the concentration of the stock solution 0.01mol The stock solution was separated and purified until / L (electric conductivity 3.16 ms / cm), and the results are summarized in Table 1.

Comparative Example 3
The separation of the stock solution was performed in the same manner as in Example 3 except that a separation apparatus comprising a stock solution chamber and a dialysate chamber with no mosaic electrode sandwiched between them was used, and the results are summarized in Table 1. According to Table 1, the permeation rate of aluminum chloride of Example 3 was 1.78 times greater than that of Comparative Example 3 by applying an alternating electric field.

  As described above, the effect on the permeation rate of the electrolyte by applying an AC electric field has a remarkable permeation promoting effect as the valence of the metal cation increases.

  The stock solution chamber and the dialysate chamber are composed of a dialysis tank arranged with a mosaic charged membrane arranged as an ion permeable membrane, and the dialysis tank is equipped with an AC electrode. Since current is applied, a large concentration gradient of ions near the membrane can be relaxed, allowing ions to move quickly to the membrane surface, and further facilitating the movement of ions from the membrane surface of the stock chamber to the dialysate chamber. In addition, not only an electrolyte composed of monovalent ions but also an electrolyte composed of multivalent ions can be efficiently separated.

  Therefore, the separation apparatus of the present invention is suitable for desalting in industries such as the chemical industry, electronics / electric industry, fermentation industry, food industry, biological industry, and pharmaceutical industry, and desalting seawater, specifically, proteins, amino acids. Applying to a wide range of applications such as desalting of dyes, pigments, surfactants, etc., and desalting in fields where electrodialysis has not been applied due to alteration of target substances due to heat generation, membrane contamination due to ion adsorption, etc. it can.

The figure explaining the separation apparatus of this invention.

Claims (4)

An apparatus for separating an electrolyte used for separating the electrolyte from an electrolyte solution containing an electrolyte containing multivalent ions and a non-electrolyte,
It consists of a dialysis tank in which the stock solution chamber and the dialysate chamber are arranged with an ion-permeable membrane in between,
An electrolyte separation apparatus comprising an AC electrode chamber having an AC electrode into which an electrolyte solution is introduced in the outermost side of the dialysis tank.   2. The electrolyte separator according to claim 1, wherein the ion permeable membrane is a mosaic charged membrane comprising a cationic polymer, an anionic polymer, and a matrix which are at least partially crosslinked granular polymers. When separating the electrolyte from an electrolyte solution containing an electrolyte containing multivalent ions and a non-electrolyte using the electrolyte separator according to claim 1 or 2,
The electrolyte solution is allowed to flow into the stock solution chamber, and deionized water as a dialysate is allowed to flow into the dialysate chamber,
A method for separating an electrolyte, comprising applying an AC electric field to the electrolyte solution, the dialysate and / or the ion permeable membrane through the electrolyte solution in the AC electrode chamber.   The method for separating an electrolyte according to claim 3, wherein the stock solution chamber is pressurized to separate the electrolyte.

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