JP2006016569A - Crosslinked copolymer and fluorine ion adsorbent comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a new crosslinked copolymer that selectively adsorbs a fluorine ion and removes a fluorine ion from water containing a fluorine ion, to provide a method for producing the same and to obtain a fluorine ion adsorbent comprising the same. <P>SOLUTION: The crosslinked copolymer comprises 50-95 wt.% of a residue unit of a specific phosphoric acid ester metal salt and 50-5 wt.% of a crosslable monomer residue unit. The method for producing the crosslinked copolymer comprises mixing a lipophilic solution consisting of a specific polymerizable phosphoric acid ester, a crosslinkable monomer and an oil-soluble radical polymerization initiator with an aqueous solution of trivalent-tetravalent metal salt to prepare a water-in-oil type emulsion and subjecting the emulsion to radical polymerization reaction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel cross-linked copolymer and a method for producing the same, and more specifically, a novel cross-link capable of selectively adsorbing fluorine ions and removing fluorine ions from water containing fluorine ions. The present invention relates to a copolymer, a production method thereof and a fluorine ion adsorbent comprising the copolymer.

  In recent years, drainage standards based on the Water Pollution Control Law have been strengthened, and a technique for efficiently removing fluorine ions from wastewater has been demanded.

  Conventionally, as a technique for removing fluoride ions from wastewater, a coagulation precipitation method in which an alkali salt such as calcium hydroxide is introduced into the wastewater and separated in the form of sludge such as calcium fluoride has been employed. However, this method has a problem that, in principle, the concentration of fluorine ions cannot be reduced to 16 ppm or less due to the solubility of calcium fluoride.

  Therefore, as a method for solving the above problems, a method of combining an adsorption method with an aggregation precipitation method has been proposed. Here, the adsorption method is to adsorb fluorine ions in waste water to an adsorbing material, and after adsorbing the fluorine ions, the fluorine ions are desorbed and recovered by contacting with an alkaline aqueous solution. By repeating the adsorption and desorption, This is a method for removing fluorine ions from waste water.

  Then, as a fluorine ion adsorption resin that adsorbs fluorine ions by an adsorption method, a resin in which a metal hydrate is supported on a base resin (see, for example, Patent Document 1), and a metal is added to the ion exchange group of the ion exchange resin. What has been adsorbed (see, for example, Non-Patent Document 1) has been proposed.

Japanese Examined Patent Publication No. 02-17220 (page 3)

Kunibun Nobuhide et al., Analytical Chemistry, 1980, Vol. 29 (pages 106-109)

  However, when synthesizing the fluorine ion-adsorbing resin proposed in Patent Document 1, it is necessary to support the metal hydrate on the base resin, or the metal hydration is caused by the use of an acid or alkali during the adsorption / desorption. There was a problem that the product was eluted.

  In addition, in order to obtain an ion exchange resin used for the fluorine ion adsorption resin proposed in Non-Patent Document 1, polymerization (synthesis of base resin), reaction (introduction of ion exchange groups), and adsorption (support of metal) The process is very complicated, and it is difficult to uniformly introduce the ion exchange group into the base resin. Furthermore, the ion exchange group introduced to the inside of the resin is difficult. Has a problem that it cannot exhibit a sufficient adsorption capacity.

  Therefore, the present invention provides a novel cross-linked copolymer capable of efficiently adsorbing fluorine ions and a fluorine ion adsorbent comprising the same without carrying out a complicated operation for supporting or adsorbing a metal on a resin. It is intended to provide.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a novel cross-linked copolymer excellent in fluorine ion adsorption performance and have completed the present invention.

  That is, the present invention is characterized by comprising 50 to 95% by weight of phosphate metal salt residue units represented by the following general formula (1) and 50 to 5% by weight of crosslinkable monomer residue units. The present invention relates to a crosslinked copolymer, a production method thereof, and a fluorine ion adsorbent comprising the same.

（式中、Ｒ^１は水素またはメチル基、Ｒ^２は炭素数１〜６である直鎖状または分岐状アルキレン基、Ｒ^３は炭素数１２〜２０の直鎖状若しくは分岐状アルキル基、又は直鎖状若しくは分岐状アルケニル基を示し、Ｍは３〜４価の金属を示す。）
以下、本発明を詳細に説明する。

(Wherein R ¹ is hydrogen or a methyl group, R ² is a linear or branched alkylene group having 1 to 6 carbon atoms, R ³ is a linear or branched alkyl group having 12 to 20 carbon atoms, or A linear or branched alkenyl group, M represents a trivalent to tetravalent metal.
Hereinafter, the present invention will be described in detail.

  The crosslinked copolymer of the present invention comprises a crosslinked copolymer comprising 50 to 95% by weight of a phosphate ester metal salt residue unit represented by the general formula (1) and 50 to 5% by weight of a crosslinkable monomer residue unit. It is a polymer. Here, when the phosphate ester metal salt residue unit is less than 50% by weight, the fluorine ion adsorption performance when used as a fluorine ion adsorbent is inferior. On the other hand, when the phosphate ester metal salt residue unit exceeds 95% by weight, the resulting crosslinked copolymer is very brittle.

In the phosphate ester metal salt residue unit represented by the general formula (1) constituting the cross-linked copolymer of the present invention, R ¹ represents hydrogen or a methyl group, and R ² has 1 to 6 carbon atoms. A chain or branched alkylene group is shown. Here, the linear or branched alkylene group having 1 to 6 carbon atoms is not particularly limited, and for example, a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group, Among them, a hexylene group and the like can be mentioned. Among them, an ethylene group, a propylene group, and a butylene group are preferable because a crosslinked copolymer can be obtained particularly easily and the fluorine ion adsorption performance is excellent. R ³ represents a linear or branched alkyl group having 12 to 20 carbon atoms or a linear or branched alkenyl group. Here, the linear or branched alkyl group having 12 to 20 carbon atoms or the linear or branched alkenyl group is not particularly limited, and examples thereof include a lauryl group, a myristyl group, a cetyl group, a stearyl group, and an aralkyl group. Hexyldecyl group, octyldodecyl group, oleyl group, elaidyl group, etc. Among them, the water-in-oil emulsion is stable and efficient when performing a radical polymerization reaction with a water-in-oil emulsion as a polymerization reaction. A stearyl group, an aralkyl group, and an oleyl group are preferable because a crosslinked copolymer is obtained.

  Moreover, in the phosphate ester metal salt residue unit represented by the general formula (1) constituting the cross-linked copolymer of the present invention, M represents a trivalent to tetravalent metal, and the metal is a crosslink of the present invention. When the copolymer imparts fluoride ion adsorption performance and M is other than a trivalent or tetravalent metal, the crosslinked copolymer does not have fluoride ion adsorption performance. Here, examples of the trivalent to tetravalent metals include aluminum, iron, zirconium, cerium, lanthanum, titanium, and the like. Among them, a zirconium, lanthanum, Cerium is preferred, and these metals may be used alone or in combination of two or more.

  The crosslinkable monomer residue constituting the cross-linked copolymer of the present invention is a polymerization reaction residue of a monomer having a plurality of polymerization-reactive unsaturated bonds, such as a divinylbenzene residue and a divinyltoluene residue. Group, ethylene glycol dimethacrylate residue, ethylene glycol diacrylate residue, trimethylolpropane trimethacrylate residue, trimethylolpropane triacrylate residue, etc., and these crosslinkable monomer residues are used alone or in two kinds The above may be mixed.

  Further, the crosslinked copolymer of the present invention may contain a polymerizable monomer residue as a component of the third component or more. Examples of the polymerizable monomer residue include a styrene residue, α- Examples thereof include a methylstyrene residue, a methyl methacrylate residue, a methyl acrylate residue, an acrylonitrile residue, and a vinyl acetate residue.

  And since it becomes a crosslinked copolymer having excellent rigidity, weather resistance, and handleability, the phosphate ester metal salt residue-divinylbenzene residue crosslinked copolymer, the phosphate ester metal salt residue-divinyl. A benzene residue-styrene residue cross-linked copolymer is preferred.

  Below, an example of the manufacturing method of the crosslinked copolymer of this invention is demonstrated concretely.

  Examples of the method for producing the crosslinked copolymer of the present invention include an oleophilic solution comprising a polymerizable phosphate ester represented by the following general formula (2), a crosslinking monomer, and an oil-soluble radical polymerization initiator, and 3 A method of performing a radical polymerization reaction after preparing a water-in-oil emulsion by mixing with an aqueous solution of a tetravalent metal salt can be mentioned.

（式中、Ｒ^４は水素またはメチル基、Ｒ^５は炭素数１〜６である直鎖状または分岐状アルキレン基、Ｒ^６は炭素数１２〜２０の直鎖状若しくは分岐状アルキル基、又は直鎖状若しくは分岐状アルケニル基を示す。）
ここで、上記一般式（２）で表される重合性リン酸エステルとは、上記一般式（１）で表されるリン酸エステル金属塩残基単位を誘導する単量体であり、Ｒ^５としては、Ｒ^２と同様のものを挙げることができ、Ｒ^６としては、Ｒ^３と同様のものを挙げることができる。

(Wherein R ⁴ is hydrogen or a methyl group, R ⁵ is a linear or branched alkylene group having 1 to ⁶ carbon atoms, R ⁶ is a linear or branched alkyl group having 12 to 20 carbon atoms, or Represents a straight-chain or branched alkenyl group.)
Here, the polymerizable phosphate ester represented by the general formula (2) is a monomer that induces a phosphate ester metal salt residue unit represented by the general formula (1), and R ⁵ Can be the same as R ^2, and R ⁶ can be the same as R ³ .

  The polymerizable phosphoric acid ester can be obtained by a known method. For example, phosphorus oxychloride and acrylic acid hydroxyalkyl esters and / or methacrylic acid hydroxyalkyl esters represented by the following general formula (3): And a higher alcohol represented by the following general formula (4).

（式中、Ｒ^７は水素またはメチル基、Ｒ^８は炭素１〜６である直鎖状または分岐状アルキレン基を示す。）

(Wherein R ⁷ represents hydrogen or a methyl group, and R ⁸ represents a linear or branched alkylene group having 1 to 6 carbon atoms.)

（式中、Ｒ^９は炭素１２〜２０の直鎖状若しくは分岐状アルキル基又は直鎖状若しくは分岐状アルケニル基を示す。）
ここで、一般式（３）で表されるアクリル酸ヒドロキシアルキルエステル類及び／又はメタクリル酸ヒドロキシアルキルエステル類におけるＲ^７は水素またはメチル基を示し、Ｒ^８は炭素数１〜６である直鎖状または分岐状アルキレン基を示す。炭素数１〜６の直鎖状または分岐状アルキレン基としては特に限定されるものではなく、例えばメチレン基、エチレン基、プロピレン基、イソプロピレン基、ブチレン基、イソブチレン基、ペンチレン基、ヘキシレン基等が挙げられる。

(In the formula, R ⁹ represents a linear or branched alkyl group having 12 to 20 carbon atoms or a linear or branched alkenyl group.)
Here, in the acrylic acid hydroxyalkyl esters and / or methacrylic acid hydroxyalkyl esters represented by the general formula (3), R ⁷ represents hydrogen or a methyl group, and R ⁸ is a straight chain having 1 to 6 carbon atoms. Or a branched alkylene group. The linear or branched alkylene group having 1 to 6 carbon atoms is not particularly limited, and examples thereof include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group, and a hexylene group. Is mentioned.

R ⁹ in the higher alcohol represented by the general formula (4) represents a linear or branched alkyl group having 12 to 20 carbon atoms or a linear or branched alkenyl group. The linear or branched alkyl group or linear or branched alkenyl group having 12 to 20 carbon atoms is not particularly limited, and examples thereof include lauryl group, myristyl group, cetyl group, stearyl group, aralkyl group, and hexyl. Examples include decyl group, octyldodecyl group, oleyl group, and elaidyl group.

  The crosslinkable monomer is not particularly limited as long as it is a monomer having a plurality of polymerization-reactive unsaturated bonds. For example, divinylbenzene, divinyltoluene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane trimethyl. A methacrylate, a trimethylol propane triacrylate, etc. are mentioned, These crosslinkable monomers can also be used individually or in mixture of 2 or more types.

  The oil-soluble radical polymerization reaction initiator is not particularly limited. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis ( Azo initiators such as 4-methoxy-2,4-dimethylvaleronitrile), peroxides such as dicumyl peroxide and benzoyl peroxide, and the like. -Azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile) are preferred.

  And when it is set as the lipophilic solution which consists of this polymeric phosphate ester, a crosslinkable monomer, and an oil-soluble radical polymerization reaction initiator, other oil-soluble components may be contained, and toluene as a diluent , Lipophilic solvents such as benzene; nonionic surfactants such as sorbitan monooleate, sorbitan monostearate, polyoxyethylene sorbitan monooleate, etc. as a regulator of the stability of water-in-oil emulsions, etc. Can be used.

  Examples of the aqueous solution of the trivalent to tetravalent metal salt include aqueous chloride solutions such as zirconium chloride aqueous solution, zirconium oxychloride aqueous solution, lanthanum chloride aqueous solution, and cerium chloride aqueous solution; zirconium oxynitrate aqueous solution, lanthanum nitrate aqueous solution, and cerium nitrate aqueous solution. An aqueous solution of nitrate: an aqueous solution of sulfate such as an aqueous solution of zirconium sulfate, an aqueous solution of lanthanum sulfate, or an aqueous solution of cerium sulfate. These aqueous metal salt solutions can be used alone or in combination of two or more.

  There is no particular limitation on the method for preparing a water-in-oil emulsion comprising the lipophilic solution and an aqueous solution of a trivalent to tetravalent metal salt. For example, the polymerizable phosphate ester represented by the general formula (2), the crosslinkable monomer Water-in-oil type using an apparatus such as a homogenizer or a sonicator for an oleophilic solution composed of a monomer, an oil-soluble radical polymerization reaction initiator, and optionally a diluent, and an aqueous solution composed of water and a trivalent or tetravalent metal salt. The method of preparing an emulsion is mentioned. In this case, the mixing ratio of the lipophilic solution and the aqueous solution is preferably oil phase component / water phase component (volume ratio) = 90/10 to 50/50, particularly in the range of 80/20 to 60/40. It is preferable to prepare by.

  The radical polymerization reaction temperature after adjusting the water-in-oil emulsion is not particularly limited as long as the polymerization reaction is possible, and is, for example, 30 to 100 ° C, preferably 40 to 80 ° C. The reaction pressure is not particularly limited, and is usually performed at normal pressure. The polymerization time may be appropriately selected depending on the polymerization reaction temperature and the polymerization charge ratio, and is usually 1 to 12 hours. The atmosphere in particular during a polymerization reaction is not restrict | limited, For example, it is preferable to carry out in inert atmosphere, such as nitrogen, argon, helium.

  After the completion of the polymerization, the polymer taken out from the reaction vessel can remove a non-reacted monomer using a solvent, if necessary, to obtain a crosslinked copolymer. The solvent used in that case is not particularly limited, and examples thereof include acetone, methanol, ethanol and the like.

  For example, it is also possible to perform a polymerization reaction using monomers such as styrene, α-methylstyrene, methyl methacrylate, methyl acrylate, acrylonitrile, and vinyl acetate.

  The cross-linked copolymer obtained by carrying out a radical polymerization reaction after preparing such a water-in-oil emulsion is obtained by converting the oil phase component of the water-in-oil emulsion into a resin by polymerization, and the water phase of the water-in-oil emulsion. Since the trace of the part is formed on the resin skeleton, the porous structure is exhibited.

  The crosslinked copolymer of the present invention can adsorb fluorine ions efficiently by contacting with fluorine ion-containing water, and can be used as a fluorine ion adsorbent that efficiently adsorbs fluorine ions from waste water or the like. It will be.

And when using the cross-linked copolymer of the present invention as a fluorine ion adsorbent, it has an average particle diameter of 1 to 1000 μm and a specific surface area of 1 to 200 m ² / g because it has a particularly excellent fluorine ion adsorption action, It is preferable to exhibit a porous structure having pores with a pore size of 0.1 to 20 μm. In particular, the average particle size is 10 to 500 μm, and the specific surface area is 10 to 10 because it has excellent fluorine ion adsorption characteristics and handling properties. It is preferably 100 m ² / g and a porous structure having pores with a pore diameter of 1 to 10 μm.

  When the crosslinked copolymer of the present invention is used as a fluorine ion adsorbent, fluorine ions are efficiently removed by bringing the crosslinked copolymer into contact with fluorine ion-containing water in the same manner as conventional fluorine ion adsorbing resins. be able to. The contact method is not particularly limited. For example, a batch method in which the fluorine ion adsorbent is immersed in fluorine ion-containing water, or a column method in which the fluorine ion adsorbent is filled in a column and the fluorine ion-containing water is passed. Etc.

  The crosslinked copolymer and fluorine ion adsorbent of the present invention adsorbing fluorine ions can desorb fluorine ions by contact with an aqueous alkali solution such as an aqueous sodium hydroxide solution. The desorption method is not particularly limited as long as it is a method in which the cross-linked copolymer and the fluorine ion adsorbent are brought into contact with an alkaline aqueous solution. Similarly to the fluorine ion adsorption method described above, a batch method, a column method, etc. Is mentioned.

  Furthermore, the cross-linked copolymer and fluorine ion adsorbent of the present invention from which fluorine ions have been desorbed can adsorb fluorine ions when brought into contact with fluorine ion-containing water again, and can be used repeatedly.

  The crosslinked copolymer of the present invention is a useful fluorine ion adsorbent because it can be produced by a simple production method and can efficiently adsorb fluorine ions from water containing fluorine ions.

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited to these examples.

  The evaluation / measurement method of the crosslinked copolymer obtained by the Example is shown below.

~ Specific surface area measurement ~
The crosslinked copolymers obtained in the examples were dried at 80 ° C., and the specific surface area was determined by the BET method using a specific surface area measuring device (trade name ASAP2400, manufactured by micrometrics).

~ Zirconium content measurement ~
The obtained cross-linked copolymer was melted with alkali and then converted into a solution, and the zirconium content was measured using an inductively coupled plasma emission spectrometer (trade name UOP-1 MK-II, manufactured by Kyoto Koken).

~ Observation of porosity ~
The obtained cross-linked copolymer was broken, gold was deposited on the fractured surface, and the fractured surface was observed with an electron microscope (trade name: SIGMA-II, manufactured by Akashi Seisakusho) to observe the porosity.

Synthesis example 1 (Synthesis example of polymerizable phosphate ester)
In a 1 L four-necked flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, 50 g (0.33 mol) of phosphorus oxychloride and 180 ml of tetrahydrofuran were placed and cooled to −25 ° C. A solution of 88 g (0.33 mol) of oleyl alcohol and 36 g (0.36 mol) of triethylamine in 100 ml of tetrahydrofuran was dropped into the phosphorus oxychloride solution. During the dropping, the temperature was kept within the range of -20 to -30 ° C and stirring was performed.

  After dropwise addition of the whole amount, the mixture was further stirred for 3 hours, and then a solution of 43 g (0.33 mol) of 2-hydroxyethyl methacrylate and 36 g (0.36 mol) of triethylamine in 50 ml of tetrahydrofuran was dropped. After the entire amount was dropped, the mixture was further stirred for 4 hours in the range of -20 to -30 ° C. Thereafter, the precipitated triethylamine hydrochloride was removed by filtration, and 50 g of ion-exchanged water and 0.1 g of methoxyhydroquinone were added to the filtrate, followed by heating at 40 ° C. for 2 hours.

  After completion of the reaction, tetrahydrofuran was distilled off by evaporation, and the organic phase and the aqueous phase were separated from the residue. Sodium sulfate was added to the organic phase for drying, and then the organic phase was further concentrated under reduced pressure to obtain 155 g of a brown liquid. The brown liquid was confirmed to be a polymerizable phosphate ester having an ethyl methacrylate group and an oleyl group by proton nuclear magnetic resonance measurement.

Example 1
13.7 g of a polymerizable phosphate ester having an ethyl methacrylate group and an oleyl group obtained in Synthesis Example 1, 12.0 g of divinylbenzene, 144.7 g of toluene, and 2,2′-azobis (2,4-dimethylvaleronitrile) 0.5 g of a uniform lipophilic solution was mixed with an aqueous solution of 4.7 g of zirconium oxychloride and 90 g of pure water, and stirred at 10,000 rpm for 5 minutes using a homogenizer to prepare a water-in-oil emulsion.

  The obtained emulsion was held at 60 ° C. for 6 hours while stirring in a 300 ml four-necked flask equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a thermometer, thereby carrying out a radical polymerization reaction. After completion of the polymerization reaction, the polymerization reaction product in the flask was washed with acetone, and finally washed with pure water to obtain a phosphate ester zirconium salt residue unit having an ethyl methacrylate group and an oleyl group / divinylbenzene residue unit = A cross-linked copolymer consisting of 56.5 / 43.5 (% by weight) was obtained. The yield at that time was 63%.

The obtained crosslinked copolymer has a porous structure having pores with an average particle diameter of 80 μm, a specific surface area of 47 m ² / g, and a pore diameter of 4 μm, and the zirconium content was 7.5% by weight. It was. Moreover, the observation result of the internal structure of this crosslinked copolymer is shown in FIG.

  Further, 1.0 g of the obtained crosslinked copolymer was immersed in 100 ml of an aqueous solution prepared at pH 3.0 and pH 6.0 at a fluorine ion concentration of 50 mg / l, and left to stand in a 23 ° C. constant temperature bath for 6 hours. After 18 hours, fluorine ions were adsorbed and the fluorine ion adsorption performance was evaluated. The fluorine ion equilibrium adsorption amount was evaluated by measuring the residual fluorine ion concentration in the aqueous solution. As a result, the pH 3.0 aqueous solution was 10 mg / l (10 ppm), and the pH 6.0 aqueous solution was 15 mg / l (15 ppm). )Met.

Comparative Example 1
By carrying out the polymerization reaction in the same manner as in Example 1 except that 13.7 g of the polymerizable phosphate ester was changed to 10.0 g and 12.0 g of divinylbenzene was changed to 15.0 g, an ethyl methacrylate group and an oleyl group were obtained. A cross-linked copolymer consisting of phosphoric acid ester zirconium salt residue unit / divinylbenzene residue unit = 43.3 / 56.7 (% by weight) was obtained. The yield at that time was 75%.

The obtained crosslinked copolymer had a porous structure having pores with an average particle size of 100 μm, a specific surface area of 58 m ² / g, and a pore size of 4 μm, and the zirconium content was 5.5% by weight. .

  Further, 1.0 g of the obtained crosslinked copolymer was immersed in 100 ml of an aqueous solution prepared at pH 3.0 and pH 6.0 at a fluorine ion concentration of 50 mg / l, and left to stand in a 23 ° C. constant temperature bath for 6 hours. After 18 hours, fluorine ions were adsorbed and the fluorine ion adsorption performance was evaluated. The fluorine ion equilibrium adsorption amount was evaluated by measuring the residual fluorine ion concentration in the aqueous solution. As a result, the pH 3.0 aqueous solution was 17 mg / l (17 ppm), and the pH 6.0 aqueous solution was 25 mg / l (25 ppm). )Met.

Comparative Example 2
By carrying out the polymerization reaction in the same manner as in Example 1 except that 13.7 g of the polymerizable phosphate ester was changed to 33.0 g and 12.0 g of divinylbenzene was changed to 1.7 g, an ethyl methacrylate group and an oleyl group were obtained. A cross-linked copolymer consisting of phosphoric acid ester zirconium salt residue unit / divinylbenzene residue unit = 95.2 / 4.8 (% by weight) was obtained.

The resulting crosslinked copolymer had a porous structure having pores with an average particle size of 70 μm, a specific surface area of 1 m ² / g, and a pore size of less than 1 μm, and the zirconium content was 3% by weight.

  Further, 1.0 g of the obtained crosslinked copolymer was immersed in 100 ml of an aqueous solution prepared at pH 3.0 and pH 6.0 at a fluorine ion concentration of 50 mg / l, and left to stand in a 23 ° C. constant temperature bath for 6 hours. After 18 hours, fluorine ions were adsorbed and the fluorine ion adsorption performance was evaluated. When the amount of fluorine ion equilibrium adsorption was evaluated by measuring the residual fluorine ion concentration in the aqueous solution, no fluorine ion was adsorbed in any case.

The electron microscope observation result of the crosslinked copolymer obtained in Example 1. FIG.

Claims (7)

A crosslinked copolymer comprising a phosphate ester metal salt residue unit represented by the following general formula (1): 50 to 95% by weight and a crosslinkable monomer residue unit of 50 to 5% by weight.

(Wherein R ¹ is hydrogen or a methyl group, R ² is a linear or branched alkylene group having 1 to 6 carbon atoms, R ³ is a linear or branched alkyl group having 12 to 20 carbon atoms, or A linear or branched alkenyl group, M represents a trivalent to tetravalent metal. The crosslinked copolymer according to claim 1, wherein the trivalent to tetravalent metal is at least one metal selected from the group consisting of zirconium, lanthanum, and cerium. The crosslinkable monomer residue unit consists of divinylbenzene residue, divinyltoluene residue, ethylene glycol dimethacrylate residue, ethylene glycol diacrylate residue, trimethylolpropane trimethacrylate residue and trimethylolpropane triacrylate residue. The cross-linked copolymer according to claim 1 or 2, wherein the cross-linked copolymer is at least one cross-linkable monomer residue unit selected from the group. In an oil, a lipophilic solution composed of a polymerizable phosphate ester represented by the following general formula (2), a crosslinkable monomer, and an oil-soluble radical polymerization initiator is mixed with an aqueous solution of a trivalent or tetravalent metal salt. A method for producing a crosslinked copolymer, wherein a radical polymerization reaction is carried out after preparing a water-type emulsion.

(Wherein R ⁴ is hydrogen or a methyl group, R ⁵ is a linear or branched alkylene group having 1 to ⁶ carbon atoms, R ⁶ is a linear or branched alkyl group having 12 to 20 carbon atoms, or Represents a straight-chain or branched alkenyl group.) A fluorine ion adsorbent comprising the cross-linked copolymer according to claim 1. 6. The fluorine ion adsorbent according to claim 5, wherein the fluorine ion adsorbent has an average particle diameter of 10 to 500 [mu] m, a specific surface area of 10 to 100 m < ² > / g, and a porous structure having pores with a pore diameter of 1 to 10 [mu] m. A method for removing fluorine ions, comprising supplying the fluorine ion adsorbent according to claim 5 or 6 to water containing fluorine ions.

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