JPH06262047A - Mosaic electrically charged membrane and preparation thereof - Google Patents

Abstract

PURPOSE:To provide a mosaic electrically charged membrane being useful for separation of an electrolyte, separation of a non-electrolyte or desalting by a simple process. CONSTITUTION:In a mosaic electrically charged membrane prepd. of a cationic polymer and an anionic polymer, at least one polymer is a sphere with a diameter of 0.01-10mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mosaic charge membrane, and more particularly to a mosaic charge membrane useful for separating an electrolyte, separating a non-electrolyte or desalting.

[0002]

2. Description of the Related Art Conventionally, a mosaic charge membrane in which a cationic polymer and an anionic polymer are alternately arranged is capable of dialyzing a low-molecular-weight electrolyte through the membrane, but not a non-electrolyte. It has a function and is expected to be used for desalination and desalination of seawater, for example, and various studies have been conducted. As a typical mosaic charge membrane, for example, the polymers of A and B are incompatible with each other, but the third polymer C and the blocked block copolymer of AC and BC are formed into a lamella or cylinder structure. And adjust both quantitatively so that
After that, an anionic group and a cationic group are introduced, or an anionic polymer and a cationic polymer are formed into a flat and mosaic ultrathin film on a suitable liquid-permeable support, and then an ultrathin film is formed thereon by an epitaxy method. Some have grown the same ionic polymer layer.

[0003]

[Problems to be solved by the invention] However,
In order to form a lamella or cylinder structure by utilizing the phase separation of two kinds of block copolymers, there is a quantitative restriction on the mixing ratio of the two and an anisotropy of both structures. It is technically quite difficult to connect the front and back of the membrane with the same type of polymer layer, and further such a phase separation structure is anisotropic and has a lamellar structure or a cylindrical structure. It is difficult to adjust the direction. Also, after such a structure is made,
Since the cationic group and the anionic group are introduced, the manufacturing process is complicated and the reaction amount of these ionic groups is also limited. In the epitaxy method,
In order to grow each ionic polymer layer on the mosaic pattern, very strict control is required for the formation of the mosaic pattern ultra-thin film and the growth of the film, and there is a problem in preparing a large-area membrane. In addition, even with any of the conventional methods, the formed membrane is very thin and has low strength, and it is not possible to form a relatively thick membrane having high strength and excellent performance. Therefore, an object of the present invention is to provide a mosaic charge membrane which is useful for separating an electrolyte, separating a non-electrolyte or desalting in a simple process.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention relates to a mosaic charge membrane made of a cationic polymer and an anionic polymer, wherein at least one polymer is a sphere having a diameter of 0.01 to 10 μm, and a method for producing the same. Is.

[0005]

By using at least one of the cationic polymer and the anionic polymer in the mosaic charge membrane as a sphere having a diameter of 0.01 to 10 μm, the electrolyte and the non-electrolyte can be selectively separated and the mechanical property of the membrane can be improved. It is possible to inexpensively provide a mosaic charge membrane having improved dynamic strength and the like.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The cationic polymer used in the present invention is a polymer having a primary to tertiary amino group or a quaternary ammonium group and a salt group of these ionic groups. The anionic polymer is a polymer having a sulfonic acid group, a carboxylic acid group, and a salt group of these ionic groups. In the case of a salt group, an anion such as hydrochloric acid, sulfuric acid, phosphoric acid, or an organic acid is used for the cationic group, and a cation such as an alkali metal ion is used for the anionic group. used.

Examples of the cationic polymer include polyvinyl pyridine and its quaternary compounds, poly 2-hydroxy-3-methacryloxypropyl trimethyl ammonium chloride, polydimethylaminoethyl methacrylate, polydiethylaminoethyl methacrylate (or salts thereof). ), Etc., or a copolymer of a plurality of monomers constituting these polymers and a copolymer with other monomers. As the anionic polymer, poly-2-acryloylamino-2-methyl-1-propanesulfonic acid, poly-2-acryloylamino-2-propanesulfonic acid, polymethacryloyloxypropylsulfonic acid,
Polysulfopropyl methacrylate, poly 2-sulfoethyl methacrylate, polyvinyl sulfonic acid, polyacrylic acid, polystyrene-maleic acid copolymers (or their acid salts), etc., or the copolymerization of a plurality of monomers constituting these polymers Examples thereof include a combination and a copolymer with another monomer.

Various methods known in the art, such as precipitation of spheres from a polymer solution, can be used to form the above-described polymer into spheres, as well as soap-free polymerization, emulsion polymerization, suspension polymerization, and reverse phase polymerization. polymerization,
A polymerization method such as seed polymerization may be used. It may be preferable to crosslink the polymer spheres. Examples of the cross-linking agent used in the case of cross-linking include divinylbenzene, methylenebisacrylamide, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and other 3- to 4-functional acrylates and methacrylates. Can be mentioned. These cross-linking agents are added in an amount of 20 per 100 parts by weight of the monomers constituting the polymer.
It is used in an amount of 0.5 parts by weight or less, preferably 0.5 to 10 parts by weight. In the present invention, it is preferable to use the crosslinked spheres and uncrosslinked spheres in combination. The diameter of the sphere used is 0.01 to 10 μm, preferably 0.02 to 1 μm.

The mosaic charged membrane of the present invention is formed using at least one of the polymer spheres as described above, but it is possible to use a suitable liquid permeable support to reinforce the formed membrane. preferable. Examples of the liquid-permeable support include woven cloth, non-woven cloth, porous resin sheet,
A porous body such as a porous ceramic sintered body or a metal mesh is preferable. The thickness of these porous bodies is 0.01-5.
The thickness is 00 μm, preferably 0.1 to 100 μm. In the method for producing the mosaic charged membrane of the present invention, at least one of the anionic polymer and the cationic polymer needs to be a sphere, and the other polymer does not necessarily have to be a sphere.

The method of manufacturing the membrane of the present invention includes:
(1) A method of immobilizing one ionic polymer sphere on a liquid-permeable support and then filling the gap between the spheres with the other ionic monomer to polymerize the monomer.
(2) A method of mixing one ionic polymer sphere and the other ionic linear polymer solution to form a cast film (in the present invention, the “linear polymer” is distinguished from a sphere). (A polymer having a branched chain may be used as long as it is not a sphere), (3) Dispersions of different ionic polymer spheres are prepared, and the dispersions are mixed to form a cast film. (4) The other ionic linear polymer is chemically bonded to the surface of one ionic polymer sphere to form a core-shell type polymer, which is cast to form a film. (5) Dispersion liquids of different ionic polymer spheres are prepared and mixed to form a cast film, and the gap is filled with one ionic polymer or Mo Filling mer, how to further polymerization when using monomers, (1) to (4) methods in any combination of methods thereof.

The two types of polymer spheres used above are preferably a combination of cross-linked spheres and uncross-linked spheres, and these are mixed to form a cast film, and then the polymer spheres in the film are formed by a solvent or pressure. Ensure the connection of like ions by destroying or deforming
Also, the mechanical strength of the film can be improved.

[0012]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. Example 1 500 ml of water, 3 ml of 4-vinylpyridine and 0.1
ml of divinylbenzene and 0.1 g of 2,2′-azobis (2-methyl-2-methylpropinoamidine) dihydrochloride were charged in a flask, and the mixture was reacted at 80 ° C. for 5 hours under a nitrogen gas inflow to emulsify. A substance was obtained. 3 g of sodium chloride was added to this emulsified product, and the mixture was stirred, followed by pressure filtration using a Millipore filter, washing with water, and drying to obtain spherical poly-4-vinylpyridine having a diameter of about 300 nm. 1 g of the above polyvinyl pyridine was dispersed in methanol to a concentration of 3% by weight to prepare a dispersion liquid,
To this, 0.2 g of methyl iodide and 0.2 g of chloromethylstyrene were added and reacted at 30 ° C. for 40 hours to quaternize the nitrogen atom of the pyridine ring.

Next, a solution of polystyrene-polybutadiene-polystyrene block copolymer (polystyrene content 40% by weight) was applied onto the glass plate and dried to obtain about 10 parts.
A 0 μm thick film was formed. 40 g / m basis weight on the film
² and 50 μm thick polyester non-woven fabric were thermocompression bonded to seal the non-woven fabric. The unsealed surface of this nonwoven fabric was impregnated with the dispersion liquid of the spherical polymer obtained above, left to dry to some extent, and further dried at 60 ° C. for 12 hours. Further, an aqueous solution of sodium polystyrenesulfonate having a concentration of 10% by weight is impregnated from the surface, dried at 60 ° C., washed with water, and dried again. Then, the whole was put in water and the layer composed of the nonwoven fabric and the membrane was peeled off from the glass plate and the sealing layer to obtain a mosaic charged membrane of the present invention. The amount of charged polymer in this membrane is 4.2 g / m
^{Was 2} .

The dialysis properties of the electrolyte and non-electrolyte of the membrane were measured with the apparatus shown in FIG. 20 ml each of a 3 wt% sodium chloride aqueous solution as an electrolyte and a 0.01 mol / liter acrylamide aqueous solution as a non-electrolyte were placed in a container 1, and 40 ml of pure water was placed in a container 2. The membrane of the present invention was sandwiched between the two, and the mixture was kept at 25 ° C., stirred and kept for 3 days, and then the respective concentrations of the electrolyte and the non-electrolyte in the container were measured. As a result, the transfer amount of sodium chloride between the two containers was 50% by weight, and equilibrium was reached at this concentration, while the transfer amount of acrylamide was about 0.2% by weight. This result shows that the mosaic charge membrane of the present invention has excellent properties of selectively separating an electrolyte.

Example 2 9.7 parts of an aqueous dispersion of crosslinked poly-4-vinylpyridine spheres (solid content = 2.15% by weight, diameter about 200 nm),
9.7 parts of uncrosslinked poly-4-vinylpyridine sphere water dispersion (solid content = 2.34% by weight, diameter about 180 n)
m), an uncrosslinked copolymer of sodium styrenesulfonate and acrylamide (molar ratio 1: 1) aqueous solution (solid content 10
Wt%) and 7.4 parts of a 50 wt% glutaraldehyde aqueous solution are mixed, cast film is formed on Teflon, and air-dried. The membrane is left to stand in a methanol atmosphere for 1 day to form an uncrosslinked poly-4-vinylpyridine sphere into a film, and then the film is left to stand in a saturated gas of hydrochloric acid gas for 1 day, then washed with water and air-dried. Treatment with an atmosphere of butanol / methanol followed by complete quaternization of the nitrogen atoms of 4-vinylpyridine in an atmosphere of methyl iodide / methanol.

The mosaic charged membrane thus obtained maintains the film shape without the liquid-permeable support. The dialysis test of this membrane was carried out using the same apparatus as in Example 1 using 0.05 mol% / liter glucose and 0.05 mol / liter potassium chloride aqueous solution. The thickness of this membrane is about 150 μm and its dialysis performance is shown in FIG. As is clear from the results shown in FIG. 2, the membrane of the present invention had good separation performance between the electrolyte and the non-electrolyte. It should be noted that although a trace amount of glucose is dialyzed in FIG. 2, it is considered that this appears as a measurement error. In any case, the electrolyte was dialyzed well, the non-electrolyte was hardly dialyzed, and the separation between the electrolyte and the non-electrolyte was performed sufficiently. Moreover, since the dialysis experiment shown in FIG. 2 is performed at atmospheric pressure, it takes a long time to dialyze the electrolyte, but pressure is applied to the liquid to be dialyzed, the membrane is thinned, or the membrane is changed. Dialysis time can be significantly reduced by thinning and applying pressure.

Example 3 An uncrosslinked copolymer of the same sodium styrene sulfonate and acrylamide as used in Example 2 (molar ratio 1: 1).
Half of the sodium styrene sulfonate in the aqueous solution was replaced with a cross-linked sphere composed of sodium styrene sulfonate-styrene-acrylamido-divinylbenzene (molar ratio 50/30/10/10), and otherwise the same as in Example 2. The mosaic charged membrane of the invention was made. The thickness of this membrane was about 200 μm and its dialysis performance was similar to that of Example 2.

Example 4 A. Preparation of poly-4-vinylpyridine microgel 10 parts 4-vinylpyridine, 1 part divinylbenzene, 0.2 parts 2,2'-azobis (2-methyl-2-)
Methylpropinoamidine) dihydrochloride and 5
00 parts of water was placed in a 1 liter flask and polymerized at 70 ° C. for 7 hours in a nitrogen atmosphere. The obtained polymerization liquid is an emulsified liquid and may be purified by dialysis, or may be purified by pressure filtration and washing with water. The dried product can be redispersed in water or methanol. The particle size of the obtained polymer spheres is about 150 nm when dried and about 200 n in water.
m and about 500 nm in methanol.

B. Preparation of linear polysodium sulfonate 12 parts sodium styrene sulfonate, 4 parts acrylamide, 0.5 parts 2,2'-azobis (2-methyl-2)
-Methylpropinoamidine) dihydrochloride,
0.8 parts of diallyl malonic acid, 1 part of crotonaldehyde and 100 parts of water were placed in a flask and placed under a nitrogen atmosphere.
After reacting at 0 ° C. for 10 hours, the polymer is purified by an acetone-water reprecipitation method and then dried at room temperature. The obtained polymer has a molecular weight of about 44,000 (GPC) and is a polymer having an amidino group at one end.

C. Preparation of Core-Shell Type Polymer 1 part of the linear polysodium sulfonate of B above was dissolved in 10 parts of water, and 0.5 part of sodium bicarbonate was dissolved therein.
Stir for hours. To this, 1 part of epibromhydrin is added and reacted at 45 ° C. for 10 hours. The reaction solution is purified by dialysis. When bromine in the reaction product was ionized with alkali and quantified, the molecular weight was about 40,000 when one was attached to one end of the polymer, which was almost in agreement with the analysis result by GPC. This polymer aqueous solution was adjusted to a solid content of 5% by weight, and 40 parts thereof were taken and mixed with 10 parts of a 10% by weight poly-4-vinylpyridine microgel methanol solution shown in A above. After reacting for 24 hours at room temperature, it was filtered, washed with water and dried under reduced pressure.

Determination of aldehyde and transmission electron microscope (TE
From the observation of M), the linear polymer B is present only on the surface of the poly-4-vinylpyridine sphere, and is present in a ratio of 1 to 10 pyridine units. In some cases, the nitrogen atom of the pyridine ring can be completely quaternized with methyl iodide or the like. The core-shell type polymer thus obtained was used in place of the poly-4-vinylpyridine sphere of Example 2, and the sulfonic acid equivalent to the poly-4-vinylpyridine in the core-shell was used. Mixed with an aqueous solution of linear sodium polysulfonate to form a cast film, and after the same treatment as in Example 2, the membrane is placed on a stainless steel porous body to obtain 200 kg / cm 2.
Pressure was applied at a pressure of ² . The mosaic charged membrane of the present invention thus obtained exhibited a more excellent desalting effect by applying pressure to an aqueous solution of a salt to be dialyzed.

[0022]

[Effects] According to the present invention as described above, by using ionic polymer spheres for the production of a mosaic charged membrane, the spheres in the membrane are connected isotropically, so that the electrolyte of the membrane is formed. Dialysis is dramatically improved. Further, also in the production of the membrane, since the constituent material of the membrane is sphere, it is not necessary to consider the orientation of the polymer phase. Therefore, according to the present invention, a mosaic charge membrane useful for separating an electrolyte, separating a non-electrolyte or desalting is provided in a simple process.

[0023]

[Brief description of drawings]

FIG. 1 is a diagram illustrating filtration and separation of an electrolyte and a non-electrolyte by the mosaic charge membrane of the present invention.

FIG. 2 is a diagram for explaining the separation performance of electrolyte and non-electrolyte by the mosaic charge membrane obtained in Example 1.

[Explanation of symbols]

 1: Electrolyte container 2: Non-electrolyte container 3: Membrane 4: Stirrer

Claims (9)

[Claims] 1. A mosaic charge membrane made of a cationic polymer and an anionic polymer, wherein at least one polymer is a sphere (spherical body) having a diameter of 0.01 to 10 μm. 2. The mosaic according to claim 1, wherein one of the cationic polymer and the anionic polymer is a sphere fixed to a liquid-permeable support, and the other polymer is filled in the gap between the spheres. Charged membrane. 3. The mosaic charge membrane according to claim 1, wherein one of the cationic polymer and the anionic polymer is a sphere and the other polymer is an uncrosslinked polymer. 4. The mosaic charge membrane according to claim 1, wherein both the cationic polymer and the anionic polymer are spheres. 5. The method according to claim 1, wherein one ionic sphere is immobilized on a liquid-permeable support, and then the monomer constituting the other polymer is filled in the gap between the spheres to polymerize the monomer. 1. The method for producing a mosaic charged membrane according to 1. 6. The method for producing a mosaic charge membrane according to claim 1, wherein one ionic sphere and the other ionic linear polymer solution are mixed to form a cast film. 7. The method for producing a mosaic charge membrane according to claim 1, wherein dispersion liquids of different ionic spheres are prepared, and the dispersion liquids are mixed to form a cast film. 8. A core in which the surface of one ionic sphere is chemically bonded to the other ionic linear polymer.
The method for producing a mosaic charge membrane according to claim 1, wherein the shell type polymer is cast to form a film, and the core is destroyed. 9. A dispersion of heterogeneous ionic spheres is prepared, and the dispersions are mixed to form a cast film, and the gap is filled with one ionic polymer or monomer. The method for producing a mosaic charged membrane according to claim 1, wherein the method is further polymerized.