JPH0871415A - Production of ziroconium carried ion exchange resin - Google Patents

Abstract

PURPOSE: To produce a Zr carried ion exchange resin having high fluoride ion adsorption capacity and less liable to the release of Zr by a simple method without using an org. solvent. CONSTITUTION: An aq. soln. of a compd. such as ZrOCl2 is brought into contact with a cation exchange resin and the resin is allowed to capture Zr and heated to produce the objective Zr carried ion exchange resin.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for producing a zirconium-supported ion-exchange resin, and more particularly to a method for producing a zirconium-supported ion-exchange resin capable of adsorbing fluoride ions.

[0002]

2. Description of the Related Art Polyvalent metals, particularly zirconium (Zr),
Cerium (Ce) and titanium (Ti) are known to selectively adsorb fluoride ions, and cerium-supporting resins have already been marketed as fluoride ion selective adsorption resins. However, since cerium has a +3 and +4 valence transition, there is a problem that the cerium is easily deteriorated under the influence of the redox agent. Also, a fluoride ion adsorbent using a zirconium compound has been reported.

For example, analytical chemistry (Vol. 29, 198)
0, 106-109), a column filled with a hydrogen ion exchange resin was passed through an aqueous solution of zirconium (IV) oxide nitric oxide dihydrate dissolved in 1M nitric acid at about 1% (w / v). , A zirconium type cation exchange resin in which the resin is changed to a zirconium type. Since the zirconium compound is the most stable in the case of +4 valence, this zirconium type cation exchange resin is more stable than the case of using the cerium compound, but the zirconium oxide aqueous solution is simply passed through the ion exchange resin. And then just capture it,
There is a problem that zirconium is easily desorbed from the resin, and in particular, zirconium is easily desorbed in the resin regeneration treatment.

[0004] Japanese Patent Publication No. 2-17220 describes a fluorine complex ion adsorbent comprising a zirconium hydrated oxide such as a zirconium gel oxide. But,
When zirconium hydrated oxide is used as an adsorbent as a powder, efficient treatment cannot be performed when a large amount of fluorine complex ion-containing water is treated. On the other hand, a method for obtaining a porous adsorbent in which zirconium hydrate oxide is supported on an organic polymer material is also described, and zirconium hydrate oxide particles are suspended and dispersed in a solution in which a polymer is dissolved. After that, a method of molding; a method of emulsifying or suspension polymerizing a high-molecular polymer in the presence of zirconium hydrate oxide particles to form a granule; a high-molecular polymer, a zirconium hydrate oxide and an extractant A method of extracting an extractant with a solvent after kneading and molding is disclosed. However, each of these methods involves a step of forming a porous structure, and thus the operation is complicated. Further, since it is necessary to use an organic solvent, it is necessary to treat the organic waste liquid, and it is necessary to consider environmental pollution and working environment.

Further, Japanese Patent Application Laid-Open No. 5-29494 describes a method for producing a fluoride ion adsorbent in which a porous material is impregnated with an organic solvent solution of tetraalkoxyzirconium and then hydrolyzed. But with this method,
Since an organic solvent is used, the operation of removing the organic solvent after impregnation and drying is necessary, which is complicated and has the same problem as described above. By the way, this publication describes that when the hydrolysis is carried out at a high temperature, the adhesion between the hydrous zirconium oxide and the porous material is improved, but this hydrolysis decomposes the alkoxyl group to give tetraalkoxy. This is hydrolysis for the purpose of forming hydrous zirconium oxide from zirconium, and does not suggest heat treatment of zirconium compounds other than tetraalkoxyzirconium.

[0006] In the conventional fluoride adsorbing material using hydrous zirconium oxide, since it adsorbs protons at the same time as fluoride is adsorbed, it works effectively in the acidic region of pH, but in the neutral region, the adsorbing ability remarkably decreases. There was a drawback to

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cation exchange resin having a zirconium salt supported thereon so as to have a fluoride adsorbing ability and, at the same time, to retain the ability as a proton supplier. An object of the present invention is to provide a fluoride adsorbent which sufficiently maintains a fluoride adsorption capacity in a neutral pH range. Further, in order to solve the manufacturing problems, a zirconium-supported ion exchange resin having a large adsorption capacity for fluoride ions and in which supported zirconium is difficult to desorb is manufactured by a simple method without using an organic solvent. It is an object of the present invention to propose a method for producing a zirconium-supported ion-exchange resin.

[0008]

The present invention is characterized in that an aqueous solution of a zirconium compound is brought into contact with a cation exchange resin so that zirconium is captured by the cation exchange resin, followed by heat treatment. It is a method for producing a resin.

The zirconium compound used in the present invention includes water-soluble zirconium compounds such as zirconium oxide chloride (ZrOCl ₂ ) and zirconium oxide nitrate (ZrO (NO ₃ ) ₂ ). These compounds are usually obtained in the form of a solid having water of crystallization. Of these, zirconium oxide chloride having the highest solubility in water is preferable.

As the aqueous solution of the zirconium compound, the higher the concentration of the aqueous solution used, the more the amount of the fluoride ions adsorbed will be the target resin. However, the solubility of the zirconium compound in water is relatively small. Alternatively, it is desirable to use an aqueous solution having a concentration close to that. Specifically, in the case of zirconium oxide chloride, it is desirable to use an aqueous solution of 2 to 18% by weight, preferably 2 to 10% by weight as zirconium. In order to increase the solubility of the zirconium compound, an acid such as nitric acid can be added to the aqueous solution, but since the dissociation degree between zirconium and the cation exchange resin increases as the acidity increases,
An increase in the amount of zirconium trapped cannot be expected.

The cation exchange resin to be brought into contact with such an aqueous solution of a zirconium compound is not particularly limited, but a strongly acidic cation exchange resin is preferred, and a porous strongly acidic cation exchange resin is particularly preferred. A commercial item can be used as such a cation exchange resin. In addition, a new cation exchange resin can be used as a matter of course, but a waste cation exchange resin recovered from an ultrapure water production device or the like can be recycled and used. The cation exchange resin is preferably used in the hydrogen form.

The method for bringing the aqueous solution of the zirconium compound into contact with the cation exchange resin includes immersing the cation exchange resin in the aqueous solution of the zirconium compound; passing the aqueous solution of the zirconium compound through a column packed with the cation exchange resin. A liquid or a circulating method can be adopted. The contact condition is that the water temperature is 10 to 30 ° C., preferably 20 to 30 ° C.
The temperature is preferably 4 hours or more, preferably 12 to 48 hours. By bringing them into contact with each other in this manner, zirconium is captured by the cation exchange resin.

In the method of the present invention, the ion-exchange resin having zirconium captured as described above is heat-treated so as to be stably immobilized in the resin. Heating temperature is 50-1
00 ° C, preferably 70-90 ° C, is suitable. The heat treatment time is preferably 4 hours or more, and more preferably 12 to 48 hours.

As a method of the heat treatment, a method of immersing the ion exchange resin in hot pure water at the above temperature; a method of passing or circulating hot pure water at the above temperature through a column filled with the ion exchange resin can be adopted. In warm water, an alkali such as sodium hydroxide or potassium hydroxide is added in an amount of 100 mg / l or more, preferably 0.4 to 4.0% by weight. In this case, it is preferable to perform a neutralization treatment with a dilute acid solution such as 1 to 4% by weight of diluted hydrochloric acid or diluted sulfuric acid after the heat treatment. Instead of hot pure water, a hot aqueous solution of a zirconium compound can also be used. By heat treatment in this way,
Zirconium is firmly supported on the ion-exchange resin and hardly desorbs.

The zirconium-supported ion exchange resin of the present invention thus obtained can be used as a fluoride ion adsorbent. In this case, the fluoride ions in the liquid to be treated are adsorbed to the adsorbent by, for example, passing the fluoride ion-containing water through a column filled with the adsorbent, or adding the adsorbent to the fluoride ion-containing water. Thus, fluoride ions can be removed. The amount of fluoride ions adsorbed is large. For example, when zirconium oxide chloride is used as the zirconium compound, it is possible to adsorb at least 20 g / l-resin or more of fluoride ions as F ⁻ . Even if other anions such as Cl ⁻ ions coexist in the liquid to be treated, there is almost no effect on the amount of fluoride ions adsorbed.

The zirconium-supported ion-exchange resin on which fluoride ions are adsorbed can be regenerated with a 0.5 to 2% by weight aqueous sodium hydroxide solution. in this case,
Since zirconium is firmly supported by the resin by the heat treatment, it is hardly detached from the resin by the regeneration treatment.

[0017]

According to the method for producing a zirconium-supported ion exchange resin of the present invention, an aqueous solution of a zirconium compound is brought into contact with a cation exchange resin to capture zirconium, and then heat treatment is carried out. It is possible to produce a zirconium-supported ion exchange resin which has a large adsorption capacity for fluoride ions and is less likely to desorb supported zirconium by a simple method without using.

[0018]

EXAMPLES Next, examples of the present invention will be described. Example 1 As the cation exchange resin, Diaion PK228L (manufactured by Mitsubishi Kasei Co., Ltd., trademark, porous strong acid cation exchange resin) or Levacit SP112WS (manufactured by Bayer Co., trademark) recovered from the ultrapure water production system was used. , Porous strongly acidic cation exchange resin) was used. The aqueous solution of the zirconium compound, ZrOCl ₂ · 8H ₂ O in about 80g
Was dissolved in 300 ml of pure water while stirring with a stirrer, and an aqueous solution of zirconium chloride (about 6% by weight as Zr) was used.

Each of the above-mentioned DIAION PK228L or Levatit SP112WS is placed in a 300 ml flask.
Then, 100 ml of the above-mentioned zirconium oxychloride aqueous solution was added, and the mixture was placed in a constant-temperature shaker at 25 ° C. for about 4
By shaking for 5 hours, zirconium was captured by the ion exchange resin. Next, after washing each resin with 500 ml of pure water, 120 ml of a slightly alkaline aqueous solution in which 50 mg of sodium hydroxide was dissolved in 1 liter of pure water was added, and the temperature of the constant temperature bath was set to 70 ° C. Heat treatment was performed for about 25 hours day and night to obtain a zirconium-supported ion exchange resin.

Next, the Zr-supported resin was taken out of the flask, filled with 200 ml of each in a 25 mmφ acrylic column, and washed with 1 liter of pure water. Then 0.5%
After passing 1 liter of each aqueous HCl solution, the resin was washed with 10 times (2 liters) pure water of the resin. PH on this column
7.4, F ^- the test water at a concentration of about 40 mg / l ion, F and passed through the column at downflow of SV ≒ 10 ^- were adsorption test ions.

As a result, the amount of F ⁻ ions adsorbed was 21.7 g / l-resin for Diaion PK228L and 21.6 g / l-resin for Levatit SP112WS. After completion of the adsorption test, the resin was regenerated with a 2% by weight aqueous sodium hydroxide solution. When the amount of zirconium in the reclaimed waste liquid was determined, in each case 10 mg /
1 or less, and it was confirmed that almost no desorption occurred.

After regeneration, acidification was performed by passing 1 liter of a 1% by weight aqueous solution of hydrochloric acid and washing with 2 liters of pure water.
As a result of performing the adsorption test again, the adsorption amount of F 2 ^- ion was 21.2 g / l-resin in the case of Diaion PK228L and 21.3 g / l-resin in the case of Levatit SP112WS, and was almost the same as the first adsorption. There was ability.

Example 2 The same recovery diamond ion PK228L or Levatit SP112W as in Example 1 was applied to a 25 mmφ acrylic column.
After filling 180 ml each of S, the same zirconium oxychloride aqueous solution as in Example 1 was applied using a roller pump to the SV.
The liquid was circulated through the upward flow of # 8 for about 25 hours a day and night, and zirconium was captured by the ion exchange resin. Next, after draining the liquid, back washing was performed with 1 liter of pure water. A slight alkaline aqueous solution at 55 to 60 ° C. was circulated through this column for 12 hours for heat treatment to obtain a zirconium-supported ion exchange resin. As a slightly alkaline aqueous solution, a solution prepared by dissolving 50 mg of sodium hydroxide in 1 liter of pure water was used, and heated to the above temperature in a water bath.

After the heat treatment, the sample was washed with pure water, and an adsorption test was carried out in the same manner as in Example 1, except that test water containing F ^- ion at a concentration of about 25 mg / l was used. as a result,
The adsorption amount of F ^- ion was 20.8 g / l-resin in the case of Diaion PK228L, and 20.5 g / l-resin in the case of Levatit SP112WS. After the adsorption test,
The resin was regenerated in the same manner as in Example 1 and the amount of zirconium in the regenerated waste liquid was quantified, but almost no leakage of zirconium was observed in any of the resins.

After acidification and pure water washing were performed in the same manner as in Example 1, the adsorption test was performed again. As a result, the adsorption amount of F ^- ion was 20.5 g / Diamond PK228L.
20.4 g for l-resin, Levatit SP112WS
/ L-resin and there was almost no decrease in the adsorption amount.

Example 3 As an aqueous solution of a zirconium compound, 75 g of zirconium oxide nitrate (ZrO (NO ₃ ) ₂ ) was added to 6410 ml of 0.
Using a nitric acid aqueous solution of zirconium oxide nitrate dissolved in 9N nitric acid aqueous solution (about 0.43 wt% as Zr), Zr
A supported ion exchange resin was obtained. That is, the same collection diamond ion PK as in Example 1 was applied to a 25 mmφ acrylic column.
228L or Levatit SP112WP each for 200
After being filled with ml, the nitric acid aqueous solution of zirconium oxide nitrate was passed in a downward flow of SV≈10 for 20 hours to capture zirconium on the ion exchange resin. Next, after draining, each was washed with 1 liter of pure water.
A slightly alkaline aqueous solution at 5 to 60 ° C. was circulated for 12 hours for heat treatment to obtain a zirconium-supported ion exchange resin.

Next, after washing with pure water, pH 7.2, F
An adsorption test of F ⁻ ions was conducted by passing test water containing ⁻ ions at a concentration of about 200 mg / l in a downward flow of SV≈10. As a result, the amount of F ⁻ ions adsorbed was 10.2 g / l-resin for Diaion PK228L and 11.6 g / l-resin for Levatit SP112WS. After completion of the adsorption test, the resin was regenerated in the same manner as in Example 1, and the amount of zirconium in the regenerated waste liquid was quantified. As in Example 1, no leak of zirconium was observed in any of the resins. .

Comparative Example 1 An adsorption test was performed in the same manner as in Example 1 except that the Zr-trapped ion exchange resin before the heat treatment was used. As a result, the adsorption amount of F 2 ^- ions was 20.4 g / l-resin in the case of Diaion PK228L, and 20.8 g / l-resin in the case of Levatit SP112WS.
After completion of the adsorption test, the resin was regenerated in the same manner as in Example 1, and the amount of zirconium in the regenerated waste liquid was determined to be 89 mg / l for Diaion PK228L and 93 mg / l for Levatit SP112WS.

After regeneration, 1 liter of a 0.5% by weight aqueous hydrochloric acid solution was added.
After acidification using an iter and washing with 2 liters of pure water each time, an adsorption test was performed again. As a result, the adsorption amount of F ^- ion was 16.4 g / l- in the case of Diaion PK228L.
16.6 g / l for resin and Levatit SP112WS
-Reduced by about 20% with resin.

Comparative Example 2 An adsorption test was carried out in the same manner as in Example 3 except that the Zr-trapped ion exchange resin before the heat treatment was used. As a result, the adsorption amount of F ^- ion was 5.9 g / l-resin in the case of Diaion PK228L, and Levatit P
In the case of S112WS, it was 7.4 g / l-resin. After completion of the adsorption test, the resin was regenerated in the same manner as in Example 1,
When the amount of zirconium in the reclaimed waste liquid was determined, in the case of Diaion PK228L, 68 mg / l, Levatit SP
In the case of 112WS, it was 65 mg / l.

[0031] After acidification and pure water washing in the same manner as in Comparative Example 1, as a result of the adsorption test again, F ^- adsorption of ions in the case of Diaion PK228L 5.1g / l
5.6 g / l for resin, Levatit SP112WS
-Reduced by about 25% with resin.

Continued Front Page (72) Inventor Masahiro Otsuka 2-22-2 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Kurita Technical Service Co., Ltd.

Claims (1)

[Claims] 1. A method for producing a zirconium-supported ion-exchange resin, comprising: bringing an aqueous solution of a zirconium compound into contact with a cation-exchange resin to trap zirconium in the cation-exchange resin;