JPS6138924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal-adsorbing resin obtained by graft polymerizing 2-acrylamido-2-methylpropanesulfonic acid (hereinafter referred to as AMPS) onto the surface of a chlorine-containing resin, and a method for producing the same.

Conventional metal-adsorbent resins are made by, for example, sulfonating a crosslinked copolymer of polystyrene and divinylbenzene with sulfuric acid, etc. to contain sulfonic acid groups or other carboxyl groups. is complicated. It is known that acrylic acid can be graft-polymerized to polyvinyl chloride fibers in a mixed solvent of an appropriate composition by irradiation with ionizing radiation, and that acrylic acid can be graft-polymerized to powdered polyvinyl chloride resin. .

The present inventors used polyvinyl chloride and polyvinylidene chloride resins to study the synthesis of ion exchange resins having sulfone groups with good metal adsorption properties.
That is, an acrylamide derivative (2-acrylamide-2-
The present invention is the result of research on graft polymerization using ionizing radiation irradiation using methylpropanesulfonic acid (methyl propane sulfonic acid).

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing a metal-adsorbing resin by graft polymerizing 2-acrylamido-2-methylpropanesulfonic acid onto the surface of a chlorine-containing resin.

According to the method of the present invention, the metal adsorption rate,
In particular, a metal-adsorbing resin with a very high initial adsorption rate is produced.

Further objects and advantages of the present invention will become apparent in the following.

The configuration of the present invention will be explained.

The method of the present invention involves contacting a chlorine-containing resin with AMPS in a specific solvent and then irradiating it with ionizing radiation, or grafting AMPS onto a chlorine-containing resin that has been irradiated with ionizing radiation in advance. In particular, it consists of producing a metal-adsorbing resin.

The chlorine-containing resin as the backbone polymer used in the present invention is polyvinyl chloride (PVC), a copolymer of vinyl chloride and vinyl acetate, a polyvinylidene chloride resin, and a copolymer of vinyl chloride and polyvinylidene chloride (PVD). It is a resin selected from the group consisting of, and it does not matter whether it is fibrous or particulate. If these are particles, 20 to 200 meshes (outer diameter 75 to 100
It is desirable to have a size of μ), and the degree of polymerization is also
200-3000 is good. These resins are relatively inexpensive, and the operation for introducing sulfonic acid groups (irradiation) is simple.

The vinyl compound used as a monomer in the present invention, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), is a solid with a melting point of 185°C and has the following structural formula; A typical example of the reaction solution for graft polymerization in the present invention is a two-component system of water/acetone.
Three-component systems such as water/acetone/dioxane, water/acetone/cyclohexanone can also be used. In these systems, water is the solvent for the AMPS and organic solvents such as acetone are the solvents or swelling agents for the chlorine-containing resin. The ratio of the organic solvent in the reaction solution to water is preferably 1 to 70%, but it needs to be changed as appropriate depending on the combination of the resin and the type of solvent.

In this way, by graft polymerizing AMPS under radiation irradiation using an aqueous medium containing acetone as a reaction liquid, a necessary and sufficient grafting rate of AMPS can generally be achieved, as will be explained in the examples below. At the same time, it has a metal adsorption capacity equivalent to or greater than that of conventional typical metal adsorption resins.
In addition, a metal-adsorbing resin can be obtained which has a characteristic that the metal adsorption rate, especially the initial adsorption rate, is extremely high.

A polymerization catalyst is used as a general method for initiating graft polymerization, but it has drawbacks such as the need for heating and the complicated handling of the catalyst due to its high reactivity. The ionizing radiation irradiation method has the advantage that the reaction operation is easy, such as polymerization being possible at low temperatures from room temperature to about 80°C. Further, the graft polymerization temperature of the present invention can be set within the range of 0 to 100°C, but is preferably 50°C or lower.

There are simultaneous irradiation methods and pre-irradiation methods for graft polymerization using ionizing radiation irradiation methods, but the simultaneous irradiation method in which the generated radicals etc. react immediately is preferable. Gamma rays, X-rays, beta rays,
In addition to electron beams, it is also possible to use mixed radiation from spent nuclear fuel, medium-to-high level solidified material after reprocessing, and the like. The usable dose rate range is 0.01 to ¹⁰⁹ rad/
seconds, but preferably 0.1 to ¹⁰² rad/second (300 to
3.6×10 ⁵ rad/hour), and the irradiation dose is
It should be less than 10 ⁶ rad.

When carrying out the present invention, in order to prevent loss of AMPS due to homopolymerization of AMPS in the reaction solution and gelation of the entire system, Mohr's salt (Fe(NH ₄ ) _{2 )} , which is an inhibitor of homopolymerization of AMPS, is used. (SO ₄ ) ₂・6H ₂ O),
Cuprous chloride (CuCl), _copper sulfate ( _CuSO4.5H2O )
etc. are used.

One of the most preferred embodiments of the present invention carried out by the present inventors will be described; 2 g of powdered chlorine-containing resin is weighed into a polymerization tube,
10 ml of a water/acetone mixture of AMPS was added, nitrogen gas was passed for about 2 minutes to replace oxygen in the mixture, and the mixture was melt-sealed under atmospheric pressure. A predetermined amount of AMPS was added to a mixed liquid of water and acetone at a predetermined ratio, and 0.1 mg (10 ml mixed liquid) of copper sulfate was added to suppress homopolymerization of AMPS. For PVD polymerization, a small amount of cyclohexanone was added to the system. After the glass ampoule for polymerization was melt-sealed, it was left to stand at room temperature overnight to fully blend the polymer and monomer. Polymerization is carried out by attaching a melt-sealed glass ampoule onto a disk and rotating it in a constant temperature bath set at a predetermined temperature, at a dose rate of 5×.
This was carried out by irradiating at 10 ⁴ rad/hour for a predetermined time (in-source polymerization). After irradiation, the ampoule was opened, the sample was taken out, and it was thoroughly washed with ion-exchanged water at about 50°C to remove unreacted AMPS and the like. Finally, after applying an ultrasonic cleaner for about 20 minutes, the homopolymer (Moly-AMPS) was extracted with water at about 50°C for about 16 hours. After drying under reduced pressure at 50°C overnight, it was weighed and the grafting rate was calculated.

Metal adsorption resin (graft polymer) of the present invention
The adsorption method of metal ions using was as follows; Lithium (Li) and copper (Cu) were targeted as metals. For adsorption of copper ions, a copper sulfate aqueous solution containing 100 ppm Cu ²⁺ was used. On the other hand, in the case of lithium ion adsorption, a lithium sulfate aqueous solution containing 10 ppm Li ⁺ was used. Take 20 ml of these aqueous solutions into a test tube, add a predetermined amount of graft polymer, and after a predetermined time while stirring at 25°C or 50°C, remove the supernatant (1 ml) and dilute it 20 times to remove the remaining metal ions. was quantified using an atomic absorption spectrometer (AA-855, manufactured by Japan Jarel Atsushi Co., Ltd.). When the amount of residual ions became 0, it was considered as 100% adsorption, and the amount of adsorption was determined.

In the case of Cu ²⁺ in 20ml of metal ion aqueous solution,
There are 0.031 ₅ mmol. On the other hand, the number of sulfone groups in the graft polymer is twice (0.063 m
The amount of polymer was added so that it became (mol). on the other hand,
In the case of Li ⁺ , the polymer was added in equimolar amounts (0.025 m mol).

Prior to these measurements, ion concentration absorbance calibrations were prepared for each of Cu ²⁺ and Li ⁺ .

Hereinafter, the structure and effects of the present invention will be specifically explained with reference to Examples.

Note that the percentages used in the examples are based on weight. In addition, the grafting rate is G (%) = 100 x (W ₂ −
W ₁ )/W ₁ (where W ₁ is the weight (g) of the polymer used, and W ₂ is the weight (g) of the graft polymer weighed after the experiment).

Example 1 Approximately 150 meshes of vinyl chloride/vinyl acetate copolymer (RB-
410, manufactured by Kanebuchi Chemical Co., Ltd.) in a glass ampoule, and add 4 g/3 ml of AMPS/water/acetone, respectively.
After adding 7 ml of the reaction solution and further adding 0.04% copper sulfate based on AMPS, the oxygen in the reaction solution was replaced with nitrogen. After melting, gamma rays from cobalt 60 (5×
10 ⁴ rad/hour) at 35°C for 1 hour. Immediately after polymerization, the package was opened, and the solid portion was washed with warm water at 50° C. for 48 hours to remove the water-soluble portion, and then weighed. The weight increase was 840 mg. (The grafting rate is 42%.) This graft polymer was added to an aqueous solution containing 10 ppm of copper ions, and the copper ions remaining in the aqueous solution were measured using an atomic absorption spectrometer. The adsorption amount was determined with the adsorption rate being 100% when the residual ions became 0, and compared with Amberlite (for CG-120 analysis). In this case, the resin was weighed and added so that the amount of copper ions in the aqueous solution and the amount of sulfone groups were equimolar. The amount of adsorption after 5 minutes (at 25°C) was 35% for the graft polymer of the present invention and 17% for CG-120. When we conducted the same adsorption experiment as above for lithium ions instead of copper ions, we found that in the case of the graft polymer of the present invention, the amount of adsorption was
In the case of 40%CG-120, 30% was obtained.

Example 2 Example 2 was repeated under the same conditions as Example 1 except that vinyl chloride resin powder (manufactured by Kanebuchi Kagaku Co., Ltd.) was used instead of the vinyl chloride/vinyl acetate copolymer as the backbone polymer. The grafting rate of the obtained graft polymer is
It was 13.5%. The amount of lithium ions adsorbed by this graft polymer was 23
%. On the other hand, when commercially available ion exchange diamond ion (PK-16) was used for comparison, it was 15%.

Example 3 Vinyl chloride/vinyl chloride copolymer (PVD-
The same conditions as in Example 1 were repeated except that Fs-12028) (manufactured by Kureha Chemical Industry Co., Ltd.) was used. The graft ratio of the obtained graft polymer was 10%.
Furthermore, the amount of lithium ions adsorbed by this graft polymer reached 28% one minute after the start of adsorption (25°C). The equilibrium adsorption amount was 37%, and in the case of Diamond ion (PK-16) it was 43%.

Example 4 Using the same backbone polymer as in Example 3, graft polymerization was carried out under the same conditions as in Example 4 in a system to which 0.3 ml of cyclohexanone, a solvent for vinylidene chloride resin, was added. The grafting rate was 10%, which was slightly lower than the case without the addition of cyclohexanone, but the amount of lithium ions adsorbed (25°C, after 1 minute) was 34%, and the equilibrium adsorption amount was 42%.

Example 5 The same conditions as in Example 1 were adopted, except that fibers (1000 denier) manufactured from the same vinylidene chloride resin used in Example 3 were used instead of the vinyl chloride/vinyl acetate copolymer. Here, the AMPS concentration in the reaction solution was the same as in Example 1, but water/acetone (3
A mixed solution of water/acetone/cyclohexanone (3 ml/4 ml/3 ml) was used instead of 3 ml/7 ml). The graft polymerization temperature was 50°C. Graft rate is 5%
The adsorption amount of lithium ions (25°C, after 1 minute) was 9%. When cyclohexanone is not used, no grafting occurs and the grafting rate is 0%.

Claims (1)

[Scope of Claims] 1. Irradiation of ionizing radiation to a chlorine-containing resin selected from the group consisting of polyvinyl chloride, a copolymer of vinyl chloride and vinyl acetate, polyvinylidene chloride, and a copolymer of vinyl chloride and vinylidene chloride. After that, the chlorine-containing resin and 2-acrylamido-2-methylpropanesulfonic acid are mixed with acetone or an organic solvent containing acetone, which is a solvent or swelling agent for the resin, at a ratio of 1 to 70% based on water. or contact the unirradiated chlorine-containing resin with 2-acrylamido-2-methylpropanesulfonic acid in the aqueous medium and then irradiate the chlorine-containing resin with ionizing radiation. 2 on the surface
- A method for producing a metal adsorbent resin, which comprises graft polymerizing acrylamide-2-methylpropanesulfonic acid. 2 Ionizing radiation at a dose rate of 0.01 to ¹⁰⁹ rad/sec
The method according to claim 1, wherein irradiation is performed at 10 ⁶ rad or less. 3. The method according to claim 1, wherein the ionizing radiation is irradiated at a temperature range of room temperature to 80°C. 4. The method according to claim 1, wherein the graft polymerization of 2-acrylamido-2-methylpropanesulfonic acid is carried out in the presence of an inhibitor for homopolymerization of the monomer. 5. The method according to claim 4, wherein the inhibitor is Mohr's salt, cuprous chloride or copper sulfate.