JP2008284521A - Method of manufacturing hollow fiber type amphoteric charge membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a homogeneous amphoteric charge membrane with ease and at a low cost, which is excellent in pressure resistance, durability, ion selectivity, particularly in salt permeability, and besides capable of making into a module of a small installation area, and the amphoteric charge membrane having these characteristics. <P>SOLUTION: The method of the hollow fiber type amphoteric charge membrane comprises: the process (1) of mixing a film-forming polymer, a solvent capable of dissolving the film forming polymer, and an ion exchange resin, and dispersing the ion exchange resin in the polymer solution to prepare a homogenous polymer dispersion; and the process (2) of contacting a hollow fiber melt obtained by spinning the polymer dispersion with air, thereafter immersing into a pure water, coagulating by removing the solvent from the obtained hollow fiber, and washing, wherein the ion exchange resin is a combination of a cation exchange resin and an anion exchange resin, or an amphoteric-ion exchange resin. The hollow fiber type amphoteric charge membrane prepared by the method is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hollow fiber-like amphoteric charged membrane and a method for producing the same. More specifically, in addition to excellent pressure resistance, durability, ion selectivity, etc., in particular, excellent salt permeability, it can be made into a module with a small installation area, and a homogeneous hollow fiber-like amphoteric charged membrane can be manufactured easily and inexpensively. And a hollow-fiber amphoteric charged membrane that can be suitably used for, for example, a membrane for pressure dialysis, a membrane for diffusion dialysis, a membrane for electrodialysis, and the like produced by the method.

  Among the charged membranes in which charged groups are introduced into the constituent polymer compounds, amphoteric charged membranes in which positively charged groups and negatively charged groups coexist in the membrane are used for, for example, pressure dialysis, seawater desalination, desalting, etc. In addition to being used as a membrane, it is expected to be applied in the fields of food and pharmaceuticals, and has been developed in the past.

  Among the amphoteric charged membranes, for example, a positively charged group and a negatively charged group exist as an ion exchange group, a mosaic charged membrane having ion channels penetrating the front and back of the membrane and adjacent to each other However, various proposals have been made because of excellent salt permeability and selective permeability to ions.

  For example, as one of the representative examples, a mosaic charged membrane in which two types of ion exchangers exist in a layer form and a method for producing the same have been proposed (for example, see Patent Document 1). Such a mosaic charged membrane is a polymer in which a cation exchange region and an anion exchange region are alternately arranged in layers in the thickness direction of the membrane and penetrated, and a polymer capable of introducing a cation exchange group A multi-component block copolymer in which a polymer capable of introducing an anion exchange group and a polymer which does not introduce an ion exchange group are linked, for example, a block copolymer comprising a block of styrene, butadiene, 4-vinylbenzyldimethylamine Can be produced by sulfonating the styrene moiety, quaternizing the 4-vinylbenzyldimethylamine moiety, and crosslinking the butadiene moiety.

  The mosaic charged film obtained by the method as described above can certainly use the salt concentration difference generated between the two surfaces as a driving force, and contains the organic compound using the mosaic charged film. It is possible to efficiently desalinate the aqueous solution. However, the production method requires a very complicated operation and advanced technology such as modification of a specific part of the block copolymer, and the cost is high. In addition, there is a problem that it is difficult to obtain at low cost.

  In addition to the above, a mosaic charged membrane in which two kinds of ion exchangers exist randomly and a method for producing the same have also been proposed (for example, see Patent Document 2). Such a mosaic charged membrane is a granular polymer membrane comprising a cationic polymerization component, an anionic polymerization component, and a matrix component, and at least one of the cationic polymerization component and the anionic polymerization component is cross-linked. Produced using a composition in which a cationic polymerization component and an anionic polymerization component, each of which is a crosslinked granular polymer (crosslinked polymer fine particles: microgel) having a small average particle diameter, are dispersed in an organic solvent solution of a matrix component can do.

  The mosaic charged membrane obtained by the method as described above also has good selective permeability to ions, and it is possible to efficiently transfer, separate, concentrate, adsorb, etc. the electrolyte using the mosaic charged membrane. is there. However, the above production method has a problem that it is necessary to prepare crosslinked polymer fine particles having a small average particle diameter, which requires a high level of technology and a long time. Moreover, since the resulting mosaic charged membrane is composed of a highly hydrous microgel, the pressure resistance is very low, and although it can be used as a membrane for diffusion dialysis, it can be used as a membrane for pressure dialysis. It is difficult and has the disadvantage of low availability.

  Therefore, for the purpose of improving the pressure resistance of the mosaic charged membrane, a method of sticking the mosaic charged membrane on the surface of the pressure-resistant support, or filling an ion exchanger in the pores of the porous support. Attempts have also been made to produce mosaic charged membranes. However, since the support used in these methods and the active layer in the mosaic charged membrane to be attached and the ion exchanger to be filled are not the same material in the first place, the use of the support can hardly improve the pressure resistance. Despite this, there is a problem that costs increase.

In addition, according to the field of use, further salt permeability has been required compared to the conventional one, and excellent pressure resistance against amphoteric charged membranes represented by mosaic charged membranes as described above. In addition to ion selectivity, better salt permeability is required. Furthermore, depending on the purpose of use, it is necessary to install in a small place, and development of a method capable of mass production of an amphoteric charged membrane capable of further miniaturization when modularized at low cost is also awaited.
JP 59-203613 A JP 2000-70687 A

  The present invention has been made in view of the above-described background art, and is excellent in pressure resistance, durability, ion selectivity, etc., particularly excellent in salt permeability, and can be made into a module having a small installation area and is homogeneous amphoteric. It is an object of the present invention to provide a method capable of easily and inexpensively producing a charged membrane, and an amphoteric charged membrane having these characteristics.

That is, the present invention
(A) A method for producing a hollow fiber-like amphoteric charged membrane comprising the following steps (1) and (2):
(1) Step of mixing a film-forming polymer, a solvent capable of dissolving the film-forming polymer and an ion exchange resin, and dispersing the ion exchange resin in the polymer solution to prepare a uniform polymer dispersion (2) The polymer dispersion The hollow fiber-like melt obtained by spinning the fiber is immersed in pure water after being contacted with air, the solvent is removed from the obtained hollow fiber-like film, the solidification is performed, and washing is performed. ,
The ion exchange resin is a combination of a cation exchange resin and an anion exchange resin, or an amphoteric ion exchange resin, a method for producing a hollow fiber-like amphoteric charged membrane, and (B) a hollow fiber obtained by the production method It relates to an amphoteric charged membrane.

  According to the production method of the present invention, in addition to excellent pressure resistance, durability, ion selectivity, etc., in particular excellent in salt permeability, a homogeneous hollow fiber-like amphoteric charged membrane that can be a module with a small installation area, Easy and inexpensive mass production. Further, the hollow fiber-like amphoteric charged membrane of the present invention produced by the production method has these excellent characteristics, and is suitably used for, for example, a membrane for pressure dialysis, a membrane for diffusion dialysis, a membrane for electrodialysis and the like. Can do.

(Embodiment 1)
In the method for producing a hollow fiber-like amphoteric charged membrane according to Embodiment 1 of the present invention, the following steps (1) and (2):
(1) Step of preparing a uniform polymer dispersion by mixing a film-forming polymer, a solvent capable of dissolving the film-forming polymer and an ion exchange resin, and dispersing the ion exchange resin in the polymer solution (2) The polymer dispersion The hollow fiber-like melt obtained by spinning the fiber is immersed in pure water after being brought into contact with air, and the solvent is removed from the resulting hollow fiber-like membrane to solidify and washing. FIG. 1 is a flowchart schematically showing the manufacturing method according to the first embodiment. In FIG. 1, the film-forming polymer is represented as raw material 1, the solvent is represented as raw material 2, and the ion exchange resin is represented as raw material 3.

  First, in step (1), a film-forming polymer, a solvent capable of dissolving the film-forming polymer, and an ion exchange resin are mixed, and the ion exchange resin is dispersed in a polymer solution to prepare a uniform polymer dispersion.

  In the step (1) of Embodiment 1, as long as a uniform polymer dispersion is obtained in which the ion exchange resin is dispersed in the polymer solution in which the film formation polymer is dissolved in the solvent, the film formation polymer, the solvent, and the ion exchange resin are used. There is no limitation in the order of addition. That is, for example, as shown in the flowchart of FIG. 2A, after a film-forming polymer and a solvent are mixed to prepare a uniform polymer solution, an ion exchange resin is added to the polymer solution, and the ion exchange resin is dispersed and uniformly formed. Simple polymer dispersions can be prepared. Also, for example, as shown in the flowchart of FIG. 2B, a solvent and an ion exchange resin are mixed, an ion exchange resin is dispersed in a solvent to prepare a dispersion, and then a film-forming polymer is added to the dispersion and dissolved. A uniform polymer dispersion in which an ion exchange resin is dispersed in a polymer solution can also be prepared.

  The membrane-forming polymer used in Embodiment 1 may be any polymer that can be spun by, for example, extrusion molding when forming a hollow fiber-like amphoteric charged membrane. Those capable of imparting chemical properties, solvent resistance, water resistance, durability and the like are preferred. Examples of such a film-forming polymer include polysulfone resins, polyarylate resins, polyamide resins, polyimide resins, polyamideimide resins, polyurethane resins, fluorine resins, silicone resins, and the like. Or 2 or more types can be used simultaneously.

The polysulfone resin is a polymer having a sulfonyl bond (—SO ₂ —) in the molecule, and examples thereof include polysulfone, polyethersulfone, and polyphenylsulfone.

  The polyarylate resin is a polymer having an ester bond (—COO—) in the molecule, and examples thereof include polyesters of dihydric phenols and aromatic dicarboxylic acids.

  The polyamide-based resin is a polymer having an amide bond (—NHCO—) in the molecule. For example, a polymer obtained by polycondensation of diamine and dibasic acid, lactam ring-opening polymerization, polycondensation of aminocarboxylic acid, or the like. Is exemplified.

  The polyimide resin is a polymer having an imide bond (—CONHCO—) in the molecule. For example, in addition to a polymer obtained by condensation polymerization of biphenyltetracarboxylic dianhydride and diamine, for example, polyetherimide, etc. Are also illustrated.

  The polyamide-imide resin is a polymer having both an amide bond and an imide bond in the molecule, for example, a polymer obtained by a reaction between trimellitic anhydride and diisocyanate or a reaction between trimellitic anhydride chloride and diamine. Also included are aromatic polyamideimides by reaction of trimellitic anhydride with diphenylalkyl diisocyanate and the like.

  The polyurethane resin is a polymer having a urethane bond (—OCONH—) in the molecule. For example, in addition to a polymer obtained by a reaction of a polyisocyanate such as an aliphatic polyisocyanate and a polyol such as tetramethylene glycol, a polyurethane resin Urea resins are also exemplified.

  The fluorine-based resin is a polymer in which hydrogen atoms of an alkylene main chain such as polytetrafluoroethylene are substituted with fluorine atoms, and other examples include sulfonated products thereof.

  The silicone resin is a polymer having a siloxane bond (—Si—O—Si—) in the molecule, and examples thereof include polyalkylsiloxanes such as polymethylsiloxane.

  The number average molecular weight of the film-forming polymer used in Embodiment 1 is not particularly limited.

  The solvent used in Embodiment 1 is not particularly limited as long as it can dissolve the film-forming polymer, and is preferably selected as appropriate according to the type of the film-forming polymer.

  Examples of the solvent capable of dissolving the film-forming polymer include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, Examples thereof include nitrogen-containing organic solvents such as N, N-dimethylacetamide and N, N-diethylacetamide; ether organic solvents such as dioxane and tetrahydrofuran; ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone. Among these, for example, when a polysulfone-based resin is used as the film-forming polymer, it is preferable to use a nitrogen-containing organic solvent from the viewpoint of solubility, and N-methyl-2-pyrrolidone is particularly preferable.

  In the first embodiment, a combination of a cation exchange resin and an anion exchange resin or an amphoteric ion exchange resin is used as the ion exchange resin.

Examples of the cation exchange resin include sulfonic acid groups (—SO ₃ H), carboxylic acid groups (—COOH), phosphonic acid groups (—PO ₃ H ₂ , —PO ₄ H), phenol groups ( -C ₆ H ₄ OH), sulfoethyl _{(- (CH 2) 2 SO} 2 OH), phosphomethyl group _{(-CH 2 PO (OH) 2} ), carboxymethyl group (-OCH ₂ COOH), iminodiacetic acid group ( _{-N = C (CH 2 COOH)} 2), acidic resins having iminodiacetic acid ester groups _{(-N = C (CH 2 COOR} ) 2) or the like. Representative examples of the cation exchange resin include, for example, Amberlite IR-120B (trade name, manufactured by Organo Corporation, ion exchange capacity: 1.9 meq / mL).
And sulfonic acid group-containing cation exchange resins. Although there is no particular limitation, for example, a cation exchange resin having an ion exchange capacity of about 1 to 2.5 meq / mL can be suitably used.

Examples of the anion exchange resin include a quaternary ammonium group (—NR ₃ ), a tertiary amino group (—NR ₂ ), a secondary amino group (—NHR), and a primary amino group in the molecule. (—NH ₂ ), 2-hydroxypropylamino group (—OC ₂ H ₄ N (C ₂ H ₅ ) CH ₂ CH (OH) CH ₃ ), triethylamino group (— (CH ₂ ) ₂ N (C ₂ H _{5) 3),} polyethylene imino group _{(- (CH 2 CH 2 NH} ) x CH 2 CH 2 NH 2), diethylaminoethyl group _{(- (CH 2) 2 N} (C 2 H 5) 2), p- aminobenzyl Group (—CH ₂ —C ₆ H ₄ —NH ₂ ), N-methylglucamine group (—CH ₂ —N (CH ₃ ) —CH ₂ — (C (OH) H) ₄ —CH ₂ OH), etc. The basic resin which has. As a typical example of the anion exchange resin, for example, Amberlite IRA-410J (trade name, manufactured by Organo Corporation, ion exchange capacity: 1.4 meq / mL)
And quaternary ammonium group-containing anion exchange resins. Although there is no particular limitation, for example, an anion exchange resin having an ion exchange capacity of about 1 to 2.5 meq / mL can be suitably used.

  When a combination of the cation exchange resin and the anion exchange resin is used as the ion exchange resin, the combination of the two is intended to permeate in the solution to be treated, for example, depending on the purpose of use of the resulting hollow fiber-like amphoteric charge membrane. It is preferable to change appropriately according to the kind of ion to be performed. Further, it is preferable to appropriately select the film-forming polymer and the solvent in consideration of the types of these ion exchange resins.

  The use ratio of the cation exchange resin and the anion exchange resin may be appropriately adjusted according to the ion exchange capacity of each, but the cation exchange resin / anion exchange resin (weight ratio) is usually 40/60 or more. Further, it is preferably 45/55 or more, 60/40 or less, and more preferably 55/45 or less.

Examples of the amphoteric ion exchange resin include sulfonic acid groups (—SO ₃ H), carboxylic acid groups (—COOH), phosphonic acid groups (—PO ₃ H ₂ , —PO ₄ H), phenol groups ( -C ₆ H ₄ OH), sulfoethyl _{(- (CH 2) 2 SO} 2 OH), phosphomethyl group _{(-CH 2 PO (OH) 2} ), carboxymethyl group (-OCH ₂ COOH), iminodiacetic acid group ( Cation exchange groups such as —N═C (CH ₂ COOH) ₂ ) and iminodiacetic ester groups (—N═C (CH ₂ COOR) ₂ ), quaternary ammonium groups (—NR ₃ ), third Primary amino group (—NR ₂ ), secondary amino group (—NHR), primary amino group (—NH ₂ ), 2-hydroxypropylamino group (—OC ₂ H ₄ N (C ₂ H ₅ ) CH ₂ CH (OH) CH ₃ ), triethylamino group (— (CH ₂ ) ₂ N (C ₂ H ₅ ) ₃ ), polyethyleneimino group (— (CH ₂ CH ₂ NH) _x CH ₂ CH ₂ NH ₂ ), diethylaminoethyl group (— (CH ₂ ) ₂ N (C ₂ H ₅ ) ₂ ), P-aminobenzyl group (—CH ₂ —C ₆ H ₄ —NH ₂ ), N-methylglucamine group (—CH ₂ —N (CH ₃ ) —CH ₂ — (C (OH) H) ₄ — And a resin having both an anion exchange group such as CH ₂ OH). As a representative example of the amphoteric ion exchange resin, for example, Diaion AMP01 (trade name, manufactured by Mitsubishi Chemical Corporation, ion exchange capacity: 0.9 meq / mL)
And quaternary ammonium groups and carboxylic acid group-containing amphoteric ion exchange resins. Although there is no particular limitation, for example, an amphoteric ion exchange resin having an ion exchange capacity of about 1 to 2.5 meq / mL can be suitably used.

  In Embodiment 1, as described above, as the ion exchange resin, a combination of a cation exchange resin and an anion exchange resin, or an amphoteric ion exchange resin is uniformly dispersed in a polymer solution. In order to improve the dispersibility of the resin and further improve the properties such as pressure resistance of the resulting hollow fiber-like amphoteric charged membrane, or to obtain a more homogeneous hollow fiber-like amphoteric charged membrane, all of these ion exchange resins are, for example, pulverized An ion exchange resin having a small particle size such as an ion exchange resin or an ultrafine ion exchange resin is preferred. As general ion exchange resins, there are many resins having an average particle diameter of usually about 700 to 900 μm, although they vary depending on the type. Considering the dispersibility of the ion exchange resin in the polymer solution and the pressure resistance and homogeneity of the hollow fiber amphoteric charged membrane, the average particle size is preferably as small as possible, for example, 50 μm or less, and further preferably 45 μm or less. For example, when using a pulverized ion exchange resin, considering the workability when pulverizing the ion exchange resin and the workability when preparing a polymer dispersion from the ion exchange resin, the average particle diameter of the ion exchange resin is It is preferably 0.1 μm or more, more preferably 1 μm or more. It is possible to change the salt permeability of the obtained hollow fiber amphoteric charged membrane depending on the particle size of these ion exchange resins, so the purpose of using the hollow fiber amphoteric charged membrane, that is, the hollow fiber amphoteric charged membrane is It is preferable to appropriately select and use an ion exchange resin such as a pulverized ion exchange resin or an ultrafine ion exchange resin having a suitable particle size according to the type of ions in the target solution to be treated. In addition, when using a pulverized ion exchange resin as the ion exchange resin, there is no particular limitation on the pulverization method of the ion exchange resin, and it is preferable to select a pulverization method as appropriate according to the type of the ion exchange resin.

The amount T ¹ of ion exchange resin to be dispersed is preferably determined in consideration of the amount T ² of the film-forming polymer used. When the amount T ¹ of the ion exchange resin is too large, the amount T ² of the membrane-forming polymer is conversely decreased, and there is a possibility that the film-forming property at the time of producing the hollow fiber-like amphoteric charged membrane may deteriorate. amount T ¹ of the ion-exchange resin, the ratio to the total amount T of the amount T ² of the said T ¹ and the membrane-forming polymer (the content of the ion exchange resin)
(T ¹ / T) × 100
Is preferably 90% by weight or less, more preferably 85% by weight or less, and particularly preferably 80% by weight or less. Also when the amount T ¹ of the ion exchange resin is small too, so the salt permeability of hollow fiber amphoteric charged membrane, particularly obtained may be lowered, the amount T ¹ of the ion-exchange resin, the T ¹ and the membrane The ratio of the formed polymer amount T ² to the total amount T is preferably 5% by weight or more, more preferably 10% by weight or more, and particularly preferably 20% by weight or more. In the first embodiment, for example, by changing the content of the ion exchange resin within the above range, the salt permeability of the obtained hollow fiber amphoteric charged membrane can be changed.

The ratio of the total amount T of the amount T ² of the amount T ¹ and the film-forming polymer ion-exchange resin, and the amount V of the solvent, the dispersibility of the ion exchange resins in the preparation of polymer dispersions, and workability, It is preferable to determine in consideration of the film-forming property at the time of producing the hollow-fiber amphoteric charged membrane, the characteristics of the target hollow-fiber amphoteric charged membrane, and the like. When the total amount T is too small, there is a risk that the film-forming property at the time of producing a hollow fiber-like amphoteric charged membrane and the characteristics of the target hollow-fiber-like amphoteric charged membrane may be deteriorated. Ratio to V T / V
Is preferably 0.2 g / mL or more, more preferably 0.25 g / mL or more, and particularly preferably 0.3 g / mL or more. If the total amount T is too large, the dispersibility and workability of the ion exchange resin when preparing the polymer dispersion may be lowered. Therefore, the ratio of the total amount T to the solvent amount V is 1. It is preferably 4 g / mL or less, more preferably 0.8 g / mL or less, and particularly preferably 0.7 g / mL or less.

  In the first embodiment, the conditions such as the dissolution temperature and the stirring time when the film-forming polymer is dissolved in the solvent or the dispersion in which the ion-exchange resin is dispersed in the solvent are the types of the film-forming polymer, the solvent, and the ion-exchange resin. The film-forming polymer may be appropriately changed so as to sufficiently dissolve, but it is usually preferable to heat to about 50 to 70 ° C., for example.

  Further, in order to disperse the ion exchange resin in the polymer solution or the solvent, they may be appropriately mixed and stirred, but the conditions such as the temperature of the system and the stirring time at this time are the conditions of these ion exchange resin, film-forming polymer and solvent. Depending on the type, it is preferable to appropriately change the ion exchange resin so as to obtain a uniform polymer dispersion sufficiently dispersed in the polymer solution. For example, when a polymer solution is obtained by heating and stirring the film-forming polymer and the solvent, an ion exchange resin may be subsequently added to the polymer solution, and the mixture may be stirred and mixed at the same temperature or at an appropriate temperature. . In addition, when a dispersion is obtained by heating and stirring the solvent and the ion exchange resin, a film-forming polymer may be continuously added to the dispersion, and the mixture may be stirred and mixed at the same temperature or at an appropriate temperature. .

  Furthermore, in this Embodiment 1, in the step (1), at least one of a combination of an inorganic cation exchanger and an inorganic anion exchanger and an inorganic amphoteric ion exchanger is used together with the ion exchange resin. It is also possible to prepare In this case, there is an advantage that a hollow fiber-like amphoteric charged membrane having both the dispersibility of the ion exchange resin and the thermal stability of the inorganic ion exchanger can be prepared.

Examples of the inorganic cation exchanger include AMD-Erba (trade name, anhydrous manganese dioxide, manufactured by Corro Erba),
HMD-Erba (trade name, hydrous manganese dioxide, manufactured by Corro Erba)
Manganese-based inorganic cation exchangers such as
IXE-300 (trade name, crystalline antimonic acid, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 4.0 meq / g),
HAP-Erba (trade name, hydrous antimony pentoxide, manufactured by Colo Erba)
Antimony inorganic cation exchangers such as
Zerwat (trade name, synthetic aluminosilicate, manufactured by Dia-Prosim),
Decalsco (F, Y) (trade name, synthetic aluminosilicate, manufactured by Permit Co., Ltd.),
Ionac C 100 (trade name, synthetic aluminosilicate, manufactured by Ionac. Chem. Comp.),
Ionac C 101 (trade name, synthetic aluminosilicate, manufactured by Ionac. Chem. Comp.),
Ionac C 102 (trade name, synthetic aluminosilicate, manufactured by Ionac. Chem. Comp.),
Allation Z (trade name, synthetic aluminosilicate, manufactured by Dia-Prosim)
Silicate inorganic cation exchangers such as
IXE-400 (trade name, titanium phosphate, manufactured by Toa Gosei Chemical Co., Ltd.),
IXE-100 (trade name, zirconium phosphate, manufactured by Toagosei Chemical Industry Co., Ltd., ion exchange capacity: 6.6 meq / g),
ZPH-Erba (trade name, zirconium phosphate, manufactured by Corro Erba),
Bio-Rad ZP-1 (trade name, zirconium phosphate, manufactured by Bio-Rad. Laboratories),
FC (FTC) (trade name, zirconium phosphate),
TDO-Erba (trade name, tin phosphate (IV), manufactured by Colo Erba)
Phosphate-based inorganic cation exchangers such as:
Bio-Rad ZM-1 (trade name, zirconium molybdate, manufactured by Bio-Rad. Laboratories),
Bio-Rad ZT-1 (trade name, zirconium tungstate, manufactured by Bio-Rad. Laboratories),
COX-Erba (trade name, cerium oxalate (III), manufactured by Colo Erba),
Bio-Rad AMP (trade name, ammonium molybdate, manufactured by Bio-Rad. Laboratories),
Bio-Rad KCF-1 (trade name, potassium hexacyanoiron (III) cobalt (II), manufactured by Bio-Rad. Laboratories),
Zeo-Dur (trade name, natural green sand, Permit Co., Ltd.),
Zerolite green sand (trade name, stabilized green sand, manufactured by Permit Co., Ltd.),
Ionac M-50 (trade name, Mn ²⁺ type green sand, manufactured by Ionac. Chem. Comp.)
Etc.

Examples of the inorganic anion exchanger include IXE-500 (trade name, hydrous bismuth oxide, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 3.9 meq / g),
IXE-530 (trade name, hydrous bismuth oxide, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 3.7 meq / g),
IXE-550 (trade name, hydrous bismuth oxide, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 4.1 meq / g)
Bismuth inorganic anion exchanger such as
IXE-700F (trade name, magnesium / aluminum, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 4.5 meq / g)
IXE-800 (trade name, zirconium series, manufactured by Toa Gosei Chemical Co., Ltd., ion exchange capacity: 1.0 meq / g)
IXE-1000 (trade name, lead hydroxide phosphate, manufactured by Toa Gosei Chemical Co., Ltd.)
Etc.

Examples of the inorganic zwitterion exchanger include OC (trade name, zirconium oxide),
Bio-Rad HZO-1 (trade name, hydrous zirconium oxide, Bio-Rad. Laboratories)
Zirconium-based inorganic amphoteric ion exchangers such as
Bio-Rad HTO-1 (trade name, hydrous titanium oxide, Bio-Rad. Laboratories)
Titanium-based inorganic amphoteric ion exchangers such as
IXE-600 (trade name, antimonic acid + hydrous bismuth oxide, manufactured by Toagosei Chemical Industry Co., Ltd., ion exchange capacity: 2.0 meq / g (cation exchange group) and 2.0 meq / g (anion exchange group) ),
IXE-633 (trade name, antimonic acid + hydrous bismuth oxide, manufactured by Toagosei Chemical Industry Co., Ltd., ion exchange capacity: 1.3 meq / g (cation exchange group) and 2.8 meq / g (anion exchange group) )
And antimony-bismuth inorganic zwitterion exchangers.

  In addition, when using the combination of the said inorganic cation exchanger and an inorganic anion exchanger with an ion exchange resin, both kind and usage rate in each combination depend on the intended purpose of the obtained hollow fiber-like amphoteric charge membrane. It is preferable to select and adjust appropriately.

  Next, in the step (2), the polymer dispersion obtained in the step (1) is spun, and the resulting hollow fiber-like melt is brought into contact with air and then immersed in pure water. The solvent is removed from the membrane, solidified, and washed to obtain a hollow fiber-like amphoteric charged membrane. In the first embodiment, before spinning the polymer dispersion, in order to further improve the homogeneity of the target hollow fiber amphoteric charged membrane, for example, a vacuum defoaming method, an ultrasonic defoaming method, a static defoaming method, etc. The polymer dispersion is preferably subjected to defoaming treatment by a method or the like.

  For example, the polymer dispersion liquid subjected to the defoaming treatment as described above is extruded as a hollow fiber-like melt from its spinning nozzle using, for example, a hollow fiber manufacturing apparatus. At this time, conditions such as the temperature in the extrusion apparatus, the flow rate of the polymer dispersion to the external flow path (polymer dispersion inflow path) of the spinning nozzle, and the flow rate of pure water to the internal flow path, for example, It is preferable to adjust appropriately in consideration of the type of ion exchange resin to be constituted, the type of polymer solution comprising a film-forming polymer and a solvent, the size of the spinning nozzle, the contact time with air after extrusion, and the like. The size (outer diameter, inner diameter) of the spinning nozzle may be appropriately determined according to the film thickness, outer diameter, and inner diameter of the target hollow-fiber amphoteric charged membrane.

  In addition, it is usually preferable to inject pure water as described above into the internal flow path of the spinning nozzle, but in addition to pure water, for example, air, nitrogen gas, and the polymer dispersion were used. It is also possible to use a mixed solution of a solvent and water. The order of injection of pure water or the like into the internal flow path and injection of the polymer dispersion liquid into the external flow path is not particularly limited, but the shape of the extruded melt as a hollow fiber is likely to be stable. Therefore, it is preferable to start injection of pure water or the like into the internal channel and then inject the polymer dispersion into the external channel.

  The hollow fiber-like melt extruded from the spinning nozzle is brought into contact with air at a temperature for a predetermined time and then immersed in pure water, and the solvent is removed from the obtained hollow fiber-like film and solidified. Conditions such as time and temperature when the hollow fiber melt is brought into contact with air are such that the surface layer of the hollow fiber melt (outside of the hollow fiber) is immersed in pure water in a state of being solidified by contact with air. It is preferable to adjust as appropriate. Further, there is no particular limitation on the temperature and immersion time of the pure water in which the hollow fiber-shaped melt with the surface layer solidified in this way is immersed, and the solvent is removed from the obtained hollow fiber-shaped membrane so that it is sufficiently and homogeneous. Although it should just adjust suitably so that it may be in the solidified state, it is preferable that the temperature of pure water is about 10-100 degreeC normally, for example.

  After the hollow fiber membrane is solidified as described above, it can be appropriately dried and washed with, for example, distilled water to obtain the desired hollow fiber amphoteric charged membrane. The thickness of such a hollow fiber-like amphoteric charged membrane may be appropriately determined according to the purpose of use, but is usually about 0.05 to 1 mm, preferably about 0.1 to 0.5 mm. Further, the outer diameter and inner diameter of the hollow-fiber amphoteric charged membrane are not particularly limited, and may be appropriately determined according to the purpose of use. Usually, the outer diameter is about 0.15 to 10 mm, and the inner diameter is 0.05 to 9. Desirably about 9 mm.

  The hollow fiber-like amphoteric charged membrane of the present invention thus obtained is bundled and accommodated in a casing (inner cylinder), for example, several tens of bundles in an amount according to the intended use, By sealing and fixing between the casing and, for example, an adhesive at the end of the casing, it is possible to obtain a module having a large membrane surface area per unit volume and reduced in size and cost.

  Thus, in the manufacturing method according to the first embodiment, a combination of a cation exchange resin and an anion exchange resin, or an ion exchange resin that is an amphoteric ion exchange resin is used. In addition to being excellent in pressure resistance, durability, ion selectivity, etc., in particular excellent in salt permeability, it is possible to produce a homogeneous hollow fiber amphoteric charged membrane that can be made into a module with a small installation area easily and inexpensively. it can.

  The hollow fiber amphoteric charged membrane of the present invention can be suitably used for desalting low molecular weight electrolytes such as sodium chloride, potassium chloride, sodium sulfate, sodium phosphate, and calcium chloride, for example, drinking water, industrial water, Desalination in water treatment industries such as pure water; Desalination of industrial effluents in chemical industry, metal industry, etc. and removal of harmful metal ions; Separation of mineral components in deep sea water; Concentrated seawater salt production, desalination; It is useful in a wide range of fields such as desalting in industry and separation and purification of ionic components.

  Next, although the hollow fiber-like amphoteric charged membrane of the present invention and the production method thereof will be described in more detail based on the following examples, the present invention is not limited to such examples.

Examples 1-2 (production of hollow fiber-like amphoteric charged membrane)
Raw materials 1 to 3 shown below were prepared. The raw materials 3 were each pulverized so as to have an average particle size shown in Table 1, and used as a pulverized ion exchange resin.
-Raw material 1 (film-forming polymer):
Polysulfone (manufactured by Aldrich, number average molecular weight: about 22000)
-Raw material 2 (solvent):
N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Raw material 3 (ion exchange resin):
(A) Cation exchange resin (Amberlite IR-120B (trade name), manufactured by Organo Corporation, sulfonic acid group-containing, ion exchange capacity: 1.9 meq / mL)
(B) Anion exchange resin (Amberlite IRA-410J (trade name), manufactured by Organo Corporation, containing quaternary ammonium group, ion exchange capacity: 1.4 meq / mL)

  Table 1 shows the amount of raw materials 1 to 3 used and the average particle diameter of raw material 3 together.

  First, the raw material 1 and the raw material 2 were sufficiently heated and stirred using a stirrer with a heater at about 60 ° C. until a uniform polymer solution was obtained. While maintaining the obtained polymer solution at 60 ° C., the raw material 3 whose particle diameter was adjusted by pulverization was added thereto, and the mixture was sufficiently heated and stirred until the raw material 3 was dispersed in the polymer solution. Got.

  The resulting polymer dispersion was degassed until there were no bubbles in the liquid, and then a hollow fiber amphoteric charged membrane was manufactured using the hollow fiber amphoteric charged membrane manufacturing system shown in the schematic diagram of FIG. In such a hollow fiber amphoteric charged membrane production system, a hollow fiber production apparatus 100 (model number: IMC-119A, manufactured by Imoto Seisakusho Co., Ltd.) includes a mixing motor 101, a mixing cylinder 102, and a temperature control apparatus 104. A spinning nozzle 107 (model number: IMC-1899, manufactured by Imoto Seisakusho Co., Ltd., outer diameter ra: 2.0 mm, inner diameter rb: 1.0 mm) is installed in the lower part. The extrudate from the spinning nozzle 107 is immersed in the water bath 108.

  As shown in the schematic enlarged view of FIG. 4, the spinning nozzle 107 is provided with inlets 107a and 107b. The inlet 107a is an inlet to the polymer dispersion inflow path (external flow path) 107a1. The inlet 107b is an inlet to the pure water inflow channel (internal channel) 107b1.

  First, the polymer dispersion liquid which was vacuum degassed by the pump 103 and ultrasonically degassed was injected into the mixing cylinder 102. Then, pure water in the liquid tank 105 is injected from the injection port 107b of the spinning nozzle 107 while adjusting the pump 106 so that the flow rate shown in Table 1 is obtained, and then the flow rate shown in Table 1 is supplied from the injection port 107a. Then, the polymer dispersion in the mixing cylinder 102 was injected. In addition, the temperature in the mixing cylinder 102 at this time was kept at about 40 ° C.

  Next, the hollow fiber-like melt extruded from the extrusion port 107c of the spinning nozzle 107 was contacted with air (room temperature), and then immersed in pure water (about 23 ° C.) in the water bath 108, and obtained. The raw material 2 (solvent) was removed from the hollow fiber membrane, solidified, and dried. In addition, the height h from the upper surface of the pure water in the water bath 108 to the extrusion port 107c of the spinning nozzle 107 is the distance that the hollow fiber melt is in contact with air, and was set to 150 mm.

  Next, the solidified and dried hollow fiber membrane was transferred to a washing tank 109 and washed with distilled water to obtain a hollow fiber amphoteric charged membrane. Table 1 shows the film thickness, outer diameter, and inner diameter of each hollow fiber amphoteric charged membrane.

  About the obtained hollow fiber-like amphoteric charged membrane, the state of its cross section was observed with a scanning electron microscope (model number: S-530, manufactured by Hitachi, Ltd., hereinafter referred to as “SEM”) (acceleration voltage: 20 kV, temperature). : 25 ° C., relative humidity: 0%). At this time, a hollow fiber-like amphoteric charged membrane was immersed in liquid nitrogen and frozen, and then a cut section was observed. FIG. 5 shows an SEM photograph of the hollow-fiber amphoteric charged membrane obtained in Example 1, and FIG. 6 shows an SEM photograph of the hollow-fiber amphoteric charged membrane obtained in Example 2. 5A is a magnification of 40 times, FIG. 5B is a magnification of 300 times, FIG. 6A is a magnification of 30 times, and FIG. 5B is a magnification of 400 times.

  From the SEM photographs in FIGS. 5 and 6, the hollow fiber-like amphoteric charged membranes obtained in Examples 1 and 2 are all in the form of a hollow fiber having a substantially uniform film thickness and are free from cracks, chips, scratches, etc. It was confirmed that it has.

Test Example 1 (Salt permeability)
First, 10 hollow fiber-like amphoteric charged membranes (outer diameter: 2.11 mm × inner diameter: 1.48 mm) obtained in Example 2 were filled and accommodated in an inner cylinder (inner diameter: 22 mm), and ethylene-vinyl acetate copolymerization was performed. A hollow fiber amphoteric charged membrane module was fabricated by bonding and fixing with a system resin adhesive. Note that the effective membrane area of the hollow fiber amphoteric charged membrane module, 56.32Cm ² in outside diameter terms are 39.50Cm ² inner diameter terms.

  Next, using the salt permeability measuring apparatus shown in the schematic diagram of FIG. 7 and the produced hollow fiber-like amphoteric charged membrane module, the salt-permeability performance of the hollow fiber-like amphoteric charged membrane was evaluated.

  In the salt permeability measuring device, 1 is a hollow fiber-like amphoteric charged membrane module, 21 and 22 are liquid tanks, 31 and 32 are flow meters, 3a is a flow control valve, 41 and 42 are pressure gauges, 4a is a pressure control valve, Reference numerals 51 and 52 denote pumps. Further, a conductivity meter 6 (model number: WM-50EG, manufactured by Toa DKK Co., Ltd.) is provided in the liquid tank 22.

500 mL of NaCl aqueous solution having a concentration of 1.0 mol / kg is put in the liquid tank 21, and 500 mL of pure water is put in the other liquid tank 22 (liquid temperature in the liquid tanks 21 and 22: about 25 ° C.). The electrical conductivity in water was measured with a conductivity meter 6 every minute for 100 minutes. From the measured values obtained, the salt permeation amount (mol · cm ⁻² ) per unit membrane area (inside diameter conversion) per unit time was calculated. The result is shown in the graph of FIG.

As a comparative example, the polymer dispersion obtained in the same manner as in Example 2 was defoamed until there were no bubbles in the liquid, and then cast on a glass plate. The film was stretched to a uniform thickness, dried at 30 ° C. for 24 hours and solidified, and then the raw material 2 (solvent) was removed from the obtained film, washed with distilled water, and the film thickness was 200 μm. A flat membrane-shaped amphoteric charged membrane was manufactured. This was used in place of the hollow fiber amphoteric charged membrane module (effective membrane area: 12.56 cm ² ), and the performance of salt permeability was evaluated in the same manner. The result is shown in FIG. In FIG. 8, the types of graphs corresponding to Example 2 and the comparative example are as shown in the legend.

  As shown in FIG. 8, the hollow-fiber amphoteric charged membrane module obtained in Example 2 has a higher salt permeation amount than the flat membrane-shaped amphoteric charged membrane manufactured from the same raw material, and the processing time has elapsed. As the difference increases, it can be seen that the hollow-fiber amphoteric charged membrane is further excellent in salt permeability compared to the flat membrane shape.

  According to the production method of the present invention, the process for producing the hollow fiber-like amphoteric charged membrane can be simplified, the required time can be shortened, and the cost can be reduced, thereby improving the production efficiency. The hollow fiber-like amphoteric charged membrane of the present invention can be used for dialysis of solutions containing various ions, and is useful in various industrial fields such as the chemical industry, metal industry, and pharmaceutical / food industry. .

The flowchart which shows roughly the manufacturing method of the hollow fiber-like amphoteric charge membrane which concerns on Embodiment 1 of this invention. The flowchart which shows roughly an example of the manufacturing method of the hollow fiber-like amphoteric charge membrane which concerns on Embodiment 1 of this invention. The flowchart which shows roughly an example of the manufacturing method of the hollow fiber-like amphoteric charge membrane which concerns on Embodiment 1 of this invention. Schematic diagram of hollow fiber amphoteric charged membrane production system Schematic enlarged view of spinning nozzle SEM photograph of the cross section of the hollow fiber-like amphoteric charged membrane obtained in Example 1 SEM photograph of the cross section of the hollow fiber-like amphoteric charged membrane obtained in Example 2 Schematic diagram of salt permeability measuring device used for salt permeability test The graph which shows the change of the salt permeation amount with respect to elapsed time in the salt permeability test about the hollow fiber-like amphoteric charged membrane obtained in Example 2 and the flat membrane-shaped amphoteric charged membrane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber-like amphoteric charge membrane module 21, 22 Liquid tank 31, 32 Flowmeter 3a Flow adjustment valve 41, 42 Pressure gauge 4a Pressure adjustment valve 51, 52 Pump 6 Conductivity meter 100 Hollow fiber production apparatus 101 Mixing motor 102 Mixing cylinder 103 Pump 104 Temperature control device 105 Liquid tank 106 Pump 107 Spinning nozzle 107a Inlet 107a1 External channel 107b Inlet 107b1 Internal channel 107c Extrusion port 108 Water bath 109 Washing tank

Claims (5)

A method for producing a hollow fiber-like amphoteric charged membrane comprising the following steps (1) and (2):
(1) Step of preparing a uniform polymer dispersion by mixing a film-forming polymer, a solvent capable of dissolving the film-forming polymer and an ion exchange resin, and dispersing the ion exchange resin in the polymer solution (2) The polymer dispersion The hollow fiber-like melt obtained by spinning the fiber is immersed in pure water after contacting with air, the solvent is removed from the obtained hollow fiber-like membrane, solidified, and washed. ,
A method for producing a hollow-fiber amphoteric charged membrane, wherein the ion exchange resin is a combination of a cation exchange resin and an anion exchange resin, or an amphoteric ion exchange resin.   The manufacturing method of Claim 1 whose average particle diameter of an ion exchange resin is 50 micrometers or less. Amount T ¹ of the ion-exchange resin, the ratio to the total amount T of the amount T ² of the amount T ¹ and the film forming polymer of the ion exchange resin (T ¹ / T) × 100
The manufacturing method of Claim 1 or 2 whose is 90 weight% or less. Ratio of total amount T of ion exchange resin amount T ¹ and film-forming polymer amount T ² to solvent amount V T / V
Is the manufacturing method in any one of Claims 1-3 whose is 0.2-1.4 g / mL.   A hollow fiber-like amphoteric charged membrane obtained by the production method according to claim 1.

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