JPS6028533B2 - Manufacturing method of heavy metal adsorbent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a heavy metal adsorbent having selective adsorption ability for uranium dissolved in water.

Conventional metal ion adsorbents include cationic or anionic resins, polyamine-based chelate resins, and iminoacetic acid-based chelate resins.

These resins adsorb many types of metals indiscriminately and have poor selective adsorption ability for specific useful metals. For example, when collecting uranium dissolved in seawater by adsorption, they have no adsorption ability at all.

Recently, titanic acid, resorcinol arsenic acid resin, triaminophenol glyoxal resin, etc. have been proposed as having adsorption ability for uranium, but their adsorption ability is small and their shape retention in water is unstable. It has not been put into practical use for some reason.

The inventors of the present invention have completed the present invention by diligently and extensively conducting systematic research to eliminate the above-mentioned problems. and a method for producing a heavy metal adsorbent having high adsorption capacity. That is, in the present invention, after diazotizing a polyaminostyrene copolymer, the general formula (1) (where R, to R4 represent hydrogen, an acetyl group, a nitro group, a hydroboxyl group, a hydroxyl group, a methyl group, a methoxy group, At least one of them is hydrogen.

) is a method for producing a heavy metal adsorbent, which is characterized by carrying out a coupling reaction with a catechol derivative represented by: The polyaminostyrene copolymer used in the present invention is a polystyrene copolymer such as styrene-divinylbenzene copolymer, styrene-vinylpyridine copolymer, styrene-chloromethylstyrene copolymer crosslinked with amines, etc. It is obtained by nitrating and reducing.

It is preferable to nitrate the polystyrene copolymer using a conventional method using a mixed system of concentrated nitric acid and concentrated sulfuric acid at a temperature of 50 to 10,000 ℃.

If the temperature is lower than 5,000, the reaction rate will be slow and it will take a long time, and if it is higher than 10,000, the substrate will be damaged or susceptible to oxidation.

Further, the reduction of the nitro group to an amino group can be achieved, for example, by heating and refluxing the nitrated polystyrene copolymer together with concentrated hydrochloric acid and stannous chloride in ethanol. If the degree of cross-linking of the polystyrene copolymer during nitration is low, the polymer may melt or become clogged, making it necessary to carry out the reaction over a long period of time.

In this case, the nitration rate tends to decrease. In addition, if the degree of crosslinking is too high, the nitration rate tends to decrease,
Since this ultimately affects the reaction rate with the catechol derivative, it is preferable to select conditions appropriately. For example, when copolymerizing styrene and divinylbenzene by emulsion polymerization or suspension polymerization, the preparation of divinylbenzene By setting the ratio to styrene in a range of 0.5 to 30 mol%, particularly preferably 0.5 to 5 mol%, the above-mentioned difficulties during nitration can be overcome. The nitration rate in this case is 80 to 95% of all benzene nuclei. In addition, when copolymerizing styrene and chloromethylstyrene, the copolymer obtained preferably has a charging ratio of chloromethylstyrene of 5 to 100% by mole relative to styrene, and is used as a woven powder or in the form of fibers to form amines. For example, an amine having at least bifunctionality such as ethylenediamine, jethylenetriamine, triethylenetetramine, piperazine, and xylylenediamine, and water or alcohols such as methanol, ethanol, propanol, and butanol, or ketones such as acetone and methyl ethyl ketone, Further, it is treated in a solvent such as acetonitrile, nitromethane, dimethylformamod, dimethylacetamide, dimethylsulfoxide, etc. by gradually increasing the temperature from room temperature to 50 to 90 qo over 1 to 1 heating time to effect crosslinking.

In this case, if the temperature increase rate is higher than the above conditions, the powder,
Alternatively, the surfaces of the fibrous materials melt and stick to each other, forming a gum-like state.

The powder or fibrous material obtained by this method has high inmeltability and infusibility and can withstand nitration conditions.
Further, the nitration rate is 75 to 95% of all benzene nuclei. The polyaminostyrene copolymer obtained by the above method is then diazotized. The shape of this copolymer is preferably powder or fiber. A polyaminostyrene copolymer is soaked in an aqueous solution containing 3 times the molar amount of hydrochloric acid based on the amount of amino groups in the copolymer, and a sodium nitrite aqueous solution is added dropwise at a temperature of 0 to 10 o'clock. do.

At this time, the saturated amount of sodium nitrite can be determined using iodine starch test paper.

That is, the saturation amount is defined as the point at which the iodine starch paper exhibits a blue color and does not fade for more than a few minutes. Similarly, the amount of amino groups that undergo diazotization in the polyaminostyrene copolymer can be determined.

The diazotized copolymer was separated from the furnace and gradually added to a 10% aqueous solution of caustic soda in which a catechol derivative was dissolved in an amount of 1 to 1 molar of the amino/base amount, and the mixture was heated in a nitrogen atmosphere at 15 to 10 o'clock. In the middle, fly worship for 1-2 hours to complete the coupling. Examples of the catechol derivatives represented by the above general formula used in the present invention include catechol 3-nitrocatechol, 4-nitrocatechol, 5-nitropyroganol, 2,3-dioxybenzoic acid, and 3,4-dioxybenzoic acid. Acid, 2,3,4-trioxybenzoic acid, 3-methylcatechol, 4-methylcatechol, 3-methoxycatechol, 4-methoxycatechol, 2,3-dioxyacetophenone, 3,4-dioxyacetophenone ,2,3,
4-trioxyacetophenone, 2,3-dioxy-4
- Methoxyacetophenone etc. are exposed.

Particularly, among the catechol derivatives represented by the above general formula, adsorbents obtained by diazo coupling of those having nitro groups, acetyl groups, and carboxyl groups in the molecule have better adsorption ability. In the case of the one having , even better adsorption ability was shown.

Confirmation and analysis of reactions in the manufacturing process of the adsorbent of the present invention were performed by the following method.

That is, in the nitration reaction of polystyrene copolymers,
The reaction rate was determined by measuring nitrogen by Kjeldahl nitrogen analysis method, and the amount of nitro groups was determined from this.

In addition, the infrared absorption spectrum of the nitrated copolymer is 1
520 skin-1,1340c-1 has absorption due to nitro group. In addition, the amino groups undergoing diazotization were measured from the saturated amount of sodium nitrite during diazotization.

This confirmed that 95 to 100% of the nitro groups were reduced to amino groups. Further, the coupling reaction rate between the diazotized copolymer and the catechol derivative can be determined by measuring the absorbance of the aqueous catechol derivative solution before and after the reaction.

It is more accurate to measure absorbance between 350 and 23 skin meters and use maximum absorption.

The reaction rate determined from this was 25-50% of the amount of diazotized amino groups. The adsorbent obtained by the method of the present invention was subjected to nitrogen analysis using the Kjeldahl method, and the coupling reaction rate estimated from this value was within a 10% error of the reaction rate determined from absorbance measurement.

When adsorbing uranium using the adsorbent obtained by the method of the present invention, the adsorbent is packed in a column or brought into contact with uranium-containing water in the form of fibers, thin films, etc., or the adsorbent is Immerse yourself in uranium-containing water and worship on a rope.

The pH value of the uranium-containing water is between 4 and 9.5, and the uranium adsorption ability is good, and the pH value is particularly preferably between 5.5 and 9.

When the pH value is below 4 or above 9.5, the amount of uranium adsorbed decreases. The adsorbent according to the present invention is capable of efficiently adsorbing and collecting uranium even from an aqueous solution in which the uranium concentration is low, such as seawater, and many types of heavy metals coexist, and its selectivity is extremely high.

Adsorbed uranium can be easily desorbed and recovered from the adsorbent with an aqueous solution containing an alkali such as soda carbonate, ammonium carbonate, caustic soda, or ammonia, depending on the acid metal such as sulfuric acid, hydrochloric acid, or nitric acid. Its industrial utility value is extremely large.

Examples will be described below.

Example 1 Styrene 10 surfactant containing 1 mol% dipinylbenzene (manufactured by Kao Atlas Co., Ltd., trade name: EMAL 10), Kyoeisha Yushi Co., Ltd., trade name: Noniolite PN-
12) was added for 1 night to emulsify it in 240 cc of water, 0.1 night of potassium persulfate was added in a nitrogen stream, and the mixture was vigorously purified at 80 pm.

After 30 minutes, 70 g of styrene containing 1 mol % of divinylbenzene was added dropwise over a period of 1 hour, and the system was further destroyed by adding concentrated hydrochloric acid, and the polystyrene copolymer was washed in a furnace.

Dry this polystyrene powder and add 15 cc of concentrated nitric acid to
The mixture was added to 40 cc of concentrated sulfuric acid over 2 hours while being stirred at 70:00, and after reacting for another 30 minutes at 70:00, it was poured into crushed ice.

The nitrated polystyrene thus obtained was thoroughly dried and then dried. When the total amount of nitrogen in the resulting copolymerization was measured by the Kjeldahl method, it was found that out of 100 female samples, 0.
It contained 68 hM nitrogen.

Calculating the nitration rate from this, 94 of the total benzene nuclei
% has undergone nitration. Subsequently, this polymer was heated under reflux in 80 cc of ethanol and 70 cc of concentrated hydrochloric acid with stannous chloride dihydrate for 60 min, filtered in an oven, washed with water, washed with an aqueous solution of caustic soda, and then washed with water. Perform diazotization.

One night of the aminated polystyrene was suspended in 25 cc of water and 25 cc of IN-hydrochloric acid, cooled on ice, and kept below 5°C. While shaking vigorously, a 1 molar solution of sodium nitrite was gradually added dropwise to 7.8 cc. The iodine starch test paper exhibited a clear blue-purple color.

Therefore, from this value, it is considered that almost all of the nitro groups were reduced and 97 to 99% of the amino groups were diazotized. The diazotized polymer is separated from the furnace and washed with ice water.

3-nitrocatechol 3.1% and 10% caustic soda 5%
The diazotized polymer was dissolved in 0 cc and maintained at 0 to 3° C. in a nitrogen atmosphere, and the diazotized polymer was added little by little, followed by heating at 0° C. for 24 hours to perform a coupling reaction.

After the reaction was completed, the resin was separated in a furnace, washed with water, and air-dried to obtain an adsorbent. The coupling reaction rate is 3- in the solution before and after the reaction.
It was determined by measuring the absorbance of nitrocatechol.

The reaction solution lcc was sampled and diluted with 2% caustic soda.
5. This absorbance was measured at 29 m using UV-200 manufactured by Shimadzu Corporation. Calculating from this, it means that 3.1mM of 3-nitrocatechol reacted. Therefore, it is considered that about 40% of the diazotized amino groups underwent the coupling reaction. A uranium adsorption test was conducted on the adsorbent thus obtained.

9 parts of the adsorbent was placed in natural seawater to which 500 parts of uranium had been added as uranyl nitrate, and the adsorbent was heated for 2 hours at 30 qo, then the adsorbent was separated in a furnace and the dried sample was placed in a Geigerflex SX crab light manufactured by Rigaku Denki. Uranium was determined using an X-ray analyzer. As a result, 385 muta of uranium was adsorbed per 100 pieces of adsorbent. This means that 9 of 3.85 uranium was adsorbed per night of adsorbent, and 77 of total uranium was adsorbed.
% has been recovered. As comparative examples, titanic acid, resorcinol-arsenic acid resin, and 2,4,6-triaminophenol glyoxal resin, which are known adsorbents, were each used at 9/100.
Table 1 shows the results of an adsorption test conducted in the same manner as in the above method using the adsorbent as the adsorbent.

However, titanic acid is obtained by neutralizing titanium tetrachloride hydrochloric acid solution with caustic soda.

Further, resorcinol-arsenic acid resin is obtained by formalin polymerization of resorcinol-arsenic acid in a conventional manner. Also, 2
, 4,6-triaminophenol-glyoxal resin is obtained by condensation polymerization of 2,4,6-triaminophenol and glyoxal using an acid catalyst. Table 1 Next, the adsorbent that was subjected to the honeycomb X-ray measurement was taken out and immersed in 10 cc of IN hydrochloric acid at 70°C, and the same treatment was performed again to elute the uranium and fluoride the uranium in the liquid. As a result of measuring ultraviolet light using the sodium sphere method, the amount of uranium in the eluate was 380.

Therefore, the uranium adsorbed on the 3-nitrocatechol-azostyrene resin is easily and almost completely desorbed.
As described above, the adsorbent obtained according to the present invention has excellent uranium adsorption ability, and often has very good adsorption rate selectivity.

Example 2 A styrene-divinylbenzene copolymer was subjected to emulsion polymerization while changing the charging ratio of divinylbenzene to styrene between 0 and 40 mol % to obtain a polymer.

Emulsion polymerization was performed in the same manner as in Example 1, and nitration, reduction, and diazo coupling of the obtained copolymer were performed in the same manner as in Example 1 to obtain an adsorbent. When performing diazo coupling, 5-nitropyroganol was used as a catechol derivative, and 3.4 days of 5-nitropyrogallol was reacted with 1 day of aminopolystyrene copolymer, and the reaction rate was 28% absorbance. It was measured with The uranium adsorption test of the obtained adsorbent and the analysis of the amount of uranium adsorbed were performed in Example 1.
I did the same thing.

The results are shown in Table 2. Table 2 As can be seen from the results in Table 2, the diazotization equivalent is determined when the copolymerization ratio of divinylbenzene is 30.
If it exceeds mol%, it will drop significantly and become impractical.

Moreover, since the nitration conditions for polystyrene not containing divinylbenzene had to be relaxed, it is thought that the amount of functional groups in the polymer was reduced. Example 3 85 parts of styrene and 25 parts of chloromethylstyrene were mixed, and bulk polymerization was carried out at 8:00 AM using penzoyl peroxide as an initiator in a sealed tube purged with nitrogen.

The obtained polymer is melt-spun at 180 mm to obtain fibers with a diameter of 10 mm. This was immersed in a 20% ethanol solvent of jethylene triamine, and after being heated for 3 hours at 3 pi○,
The temperature was gradually raised to 70 qo over 3 hours, and then further increased to 70 qo.
00 for 2 hours. The fiber thus obtained was subjected to nitration and reduction diazo coupling reaction in the same manner as in Example 1.

When performing diazo coupling, 2,3,4-trioxyacetophenone is used as a canacol derivative,
The fiber 1 was reacted with 2,3,4-trioxyacetophenone for 5 days, and the reaction rate was determined from the absorbance at 27 meters. The rate of each reaction is approximately 90% of the total benzene nuclei nitrated.
and the diazotized amino group was 7.1mM/night,
The reaction amount of 2,3,4-trioxyacetophenone is 3.
It was 1mM. 300 ml of this fibrous adsorbent was packed into a column with a diameter of 1 C to 5 skin lengths, and the pH was adjusted to 8.5 with sodium bicarbonate.
Aqueous uranyl nitrate solution (uranium concentration 5 mta/so) 5
The solution was passed through the tube for 4 hours.

Adsorbed uranium to 0. It was desorbed with 100 cc of hydrochloric acid, and the amount of uranium in the liquid was measured using a crab photometer using the sodium fluoride ball method. As a result, the amount of uranium desorbed was 235 Muta, and the fibrous adsorbent had almost completely adsorbed uranium. Therefore, this adsorbent exhibits excellent effects even when adsorbing low concentrations of uranium. Example 4 An adsorption test was conducted in the same manner as in Example 1 by reacting the aminated polystyrene obtained in Example 1 with the catechol derivative of the present invention and other phenolic compounds during diazo coupling.

The results are shown in Table 3. Table 3: The reaction rate when the above compound was diazo-coupled, that is, the percentage of amino groups that underwent diazo coupling among the amino groups of the polymer was between 32 and 40%, and although there was some variation, this It can be seen that there is a large difference in adsorption amount between the catechol conductor of the invention and other phenolic compounds.

Example 5 The catechol derivative of the present invention was diazo-coupled to the poly-IJ aminostyrene fiber used in Example 3, and an adsorption test was conducted.

The reaction method was carried out in accordance with Example 1, and the adsorption test was carried out using adsorbent 100
50mg was roped in natural seawater for 5 days. Table 4 shows the adsorption results and the reaction rate determined from the absorbance. The reaction rate is the percentage of diazotized amino groups that are coupled. Table 4 As shown in Table 4, the adsorption amount is nitro group, acetyl group,
Adsorbents with carboxyl groups are excellent; 2,3-dioxy-4-methoxyacetophenone>3,4-dioxyacetophenone, 2,3-dioxybenzoic acid>3,4
-dioxybenzoic acid, 4-nitropyrogallol > 3-nitrocanacol > 4-nitrocatechol, when these groups are located adjacent to the hydroxyl property of catechol, the effect of increasing the amount of uranium adsorption is observed. .

There is approximately 3.3 ml of uranium dissolved in natural seawater, and approximately 70% of the good material has been recovered.

Example 6 9 of 500 fibers in which 2,3-dioxybenzoic acid of Example 5 was coupled and fixed were mixed with a uranium aqueous solution (2
It was adjusted using uranyl nitrate to make it 9/so.

pH' is 6.5. ) 2. The mixture was soaked and crushed, and uranium was adsorbed by lighting for 5 hours, and uranium was quantified using the crab light X-ray method. The amount of uranium adsorbed was 720 meth per evening on the adsorbent 100. Nine of the 100 adsorbents were treated in the following manner to elute uranium. '1-0. State - Hydrochloric acid 25cc
Soak for 30 minutes at medium 60qo and repeat this twice.

(2) Soak in 25 cc of 0.1N sulfuric acid at 20 qo for 1 hour, and repeat this twice.

[31 6 in 50 cc of 10% ammonium carbonate aqueous solution
0oo, process 3 times.

[4] Soak in 50 cc of an aqueous solution containing 5% soda carbonate and 5% bicarbonate at 30°C for 1 hour.

The uranium desorbed by the above method was measured in the same manner as in Example 1 using the sodium fluoride sphere method. Table 5 shows the amount of uranium dissolved and the desorption rate. Table 5 As can be seen from Table 5, any method of attachment and detachment allows for almost complete attachment and detachment.

Example 7 A polyaminostyrene copolymer obtained in the same manner as in Example 1 and 2,3-dioxybenzoic acid (1), 2,3,4-trioxyacetophenone (0) were diazo-coupled and adsorbed. Agent (1) (b) was obtained.

For these two adsorbents, zinc chloride, lead nitrate, ferric nitrate, styrontium chloride, cupric chloride, nickel nitrate,
A 100ml aqueous solution containing 3ml each of uranyl nitrate was adjusted to pH 7.5 with sodium bicarbonate, 100ml of adsorbent was added, and the mixture was allowed to stand at room temperature for 2 hours, and the adsorbed metals were subjected to crab-light X-ray analysis.

The results are shown in Table 6.

Table 6 As can be seen from Table 6, the adsorbent produced by the method of the present invention has particularly high selectivity for uranium.

Claims (1)

[Claims] 1. After diazotizing the polyaminostyrene copolymer
General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 to R_4 are hydrogen, acetyl group, nitro group,
It represents a carboxyl group, a hydroxyl group, a methyl group or a methoxy group, at least one of which is hydrogen. ) A method for producing a heavy metal adsorbent, which comprises carrying out a coupling reaction with a catechol derivative represented by: 2
The method for producing a heavy metal adsorbent according to claim 1, wherein R_1 in general formula (1) is a nitro group, an acetyl group, or a carboxyl group.