JPS5983730A - Recovery of minute amount of metal ion - Google Patents

Abstract

PURPOSE:To recover a minute amount of a metal ion in good efficiency, by contacting chelate resin having a malonyl dihydroxum acid residue with an aqueous solution containing a minute amount of the metal ion as an adsorbing material. CONSTITUTION:Chelate resin having a malonyl dihydroxamic acid residue is used as an adsorbing material to be brought into contact with an aqueous solution containing minute amounts of a transition metal ion, a lanthanide group metal ion and an actinide group metal ion in such as seawater, mine waste water, the waste water of an atomic power plant or an aqueous solution containing used nuclear fuel to adsorb minute amounts of metal ions by the above mentioned adsorbing material. In the next step, said metal ions are desorbed by a mineral acid to be recovered in good efficiency. The above mentioned chelate resin is obtained by a method wherein insoluble resin having a malonic dialkyl ester residue is suspended in an org. solvent containing hydroxylamine to be reacted in the presence of an alcoholate catalyst such as methanol and the resulting reaction product is converted to hydroxamic acid.

Description

[Detailed Description of the Invention] The present invention relates to a method for recovering trace metal ions, and more specifically, a method for efficiently recovering trace metal ions from natural water such as seawater and industrial wastewater using a special chelate resin. It is related to.

In recent years, attention has been paid to the efficient capture of metal ions that exist in diluted solutions in order to effectively utilize valuable metal resources and prevent environmental pollution. One of these methods is heavy metal ion extraction. Chelate resins are used in a wide range of practical applications, including wastewater treatment. In particular, recently there has been a growing demand for the recycling of seawater dissolved ions and the advanced use of industrial wastewater.
Along with this, there has been a desire for the emergence of chelate resins that have extremely high performance and excellent economic efficiency.

By the way, hydroxamic acid group (CJ', pKa =
It has a weak acidity of 7.5 to 9 and is known to form stable chelate complexes with heavy metal ions. The heavy metal ions include transition metals such as titanium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, cadmium, tin,
Hafnium, tungsten, mercury, bismuth, etc. are included in the lanthanide series, such as cerium, praseodymium, cyanosome, zamarium, cadrinium, dysprosium, etc.; Can be mentioned.

Due to the characteristics of the hydroxamic acid group, monomers having this functional group are used in solvent extraction or flotation methods,2 and are widely applied in the separation of metal ions.

In recovering trace metal ions from an aqueous solution, the present inventors have made use of the characteristics of the hydroxamic acid group described above, and have found that it can be widely applied in practice, has high collection and separation performance, and is economical. As a result of intensive research in order to provide a compound with excellent properties, it was discovered that a chelate resin having a malonyl dihydroxamic acid residue could achieve the objective, and based on this knowledge, the present invention was completed.

That is, the present invention is characterized in that, in recovering trace metal ions from an aqueous solution containing trace metal ions, a chelate resin having a malonyl dihydroxamic acid residue is used as an adsorbent. This method provides a recovery method.

The chelate resin used as an adsorbent in the method G'ζ of the present invention has a malonyldihydroxamic acid residue represented by the formula -0H(CONHOH) 2 .
It is manufactured as follows.

That is, by suspending an insoluble resin containing a malonic acid dialkyl ester residue in an organic solvent containing hydroxylamine and reacting it with methanol or ethanol as an alcoholatra catalyst, hydroxamate oxidation is carried out at a high conversion rate. The desired chelate resin can be obtained.

In the malonic acid diester residue in the above-mentioned insoluble resin used as a starting material, the ester group (is bonded via one carbon atom), so the electron attraction effect of the mutual ester groups results in high reactivity. Therefore, insoluble resins containing malonic acid dialkyl ester residues are more likely to react with hydroxylamine than, for example, polyacrylic esters, and therefore hydroxamic acid residues having metal ion-trapping ability are used in high concentrations. This malonyldihydroxamic acid residue has a structure in which two adsorption functional groups are bonded to one carbon atom, so the amount of adsorption functional groups per unit weight is large. The chelate resin of the invention exhibits extremely excellent metal ion trapping ability.

The KIRE-1 resin of the present invention can be in any shape such as granules, films, and fibers, but granules are preferable, especially considering ease of manufacture and adsorption method.

In the recovery method of the present invention, either a batch method or a flow-through method may be used, but in order to adsorb and separate metal ions at a particularly dilute concentration, a large amount of water bath solution is applied to the chelate resin. Since contact is required, a liquid flow type is preferable.

The method for recovering trace metal ions of the present invention uses a chelate resin having malonyldihydroxamic acid residues, so that the hydroxamic acid groups contained in the resin efficiently form stable chelate complexes with the metal ions. For example, it is extremely useful for removing and recovering trace amounts of useful resources such as uranium, molybdenum, and/or rum in seawater, radioactive elements in radioactive wastewater, and heavy metal ions in mine and industrial wastewater.

In addition, the hydroxamic acid group is relatively stable to acids and alkalis, and the adsorbed heavy metal ions are easily desorbed by mineral acids. Can be played.

The invention will now be explained in more detail C by way of examples.

Reference Example 1 To a solution in which 0.729 (0.03 moles) of sodium hydride was suspended in 70 g of dimethylformamide, 5.6 f (0,035 moles) of malonic acid diethyl ester was added to 30 mL of a F-containing tr dinotylformamide solution. , 1 hour, 6
After heating to 0°C to complete the reaction, once returning to room temperature, chloromethylated polystyrene crosslinked with divinylbenzene (C1 content 18.9%) 29 (C
0.01 mol) was added thereto, and the mixture was heated to 80°C and reacted for 24 hours. Infrared absorption spectrum of product 6-111
As a result, it was confirmed that the malonic acid diethyl ester group had been introduced. In addition, the reaction rate was determined from the amount of decrease in chlorine, and the reaction rate (d) was 85.9%.

This polymer], Of? (0,0982 mol) was immersed in dry Henze for about 34 hours, then a methanol solution of hydroxylamine (0,393 mono(·)) was added, and the mixture was cooled with water with 7.91 mol of metallic sodium (0,344 mol). ) of 1,00 me methanol solution was added, and then 1
After cooling on ice for an hour, the mixture was returned to room temperature, heated to 70°C, and reacted for 2 days.

The reaction product was washed with ice-cold water and then washed with ice-cold water.
It was treated with 1 tl HO1 to make it H+ type, and then soaked in water so that the washing liquid became neutral. Thereafter, it was washed with methanol and then vacuum dried. As a result of infrared absorption spectrum measurement, the ester group was completely reacted, and in addition to hydroxamic acid, some carboxylic acid was observed to be produced. As a result of elemental analysis, the production rate of hydroxamic acid was 56.4%.

Reference Example 2 After suspending 8.4 f (0.35 mol) of sodium hydride in 125 dK of tetrahydrofuran, 80 f? of diethyl malonate was added. (0,5 mol) 'f
r: 75 ml of dissolved tetrahydrofuran solution was added. After returning to room temperature, 30 ml of tetrahydrofuran in which 45.759 (0.3 moles) of chloromethylated styrene had been dissolved was added dropwise to the mixed solution, and after adding sulfur powder 15' as a polymerization inhibitor, the mixture was allowed to stand for about 1 hour. after that,
The reaction was carried out at 70°C for 21 hours. After the reaction is completed, tetrahydrofuran is distilled off, and about 200 Td of ethyl acetate is added to the reaction product concentrate. , and cooled several times on ice.
After washing with ice-cold water several times, it was dried over anhydrous magnesium sulfate overnight. After ethyl acetate was distilled off, sulfur powder 17 was added and vacuum distilled to 2 mmHg, υ
1; Vinylbenozyl malonate ethyl ester was obtained at a temperature of 148 to 150°C. The reaction rate was 55%.

As a stabilizer, add 0.255' of polyvinylpyrrolidone to 4 ml of water.
Dissolve in 0 ml' and stir as described above. 21n
7! , toluene (5 ml', 1') as a solvent
(7 precipitants were added to the polymerization initiator, 1 knob of Azohis, 17 of Ronitrile was added, 1 [2
The reaction was carried out at 80υ for 2611.'7 while purging with nitrogen (・'; , 7j) for 2611.'7. After the reaction was completed, the granular product was filtered and washed with water. After purifying the vacuum cleaner with (1) -C acetate], remove the vacuum, empty and 1 (Z
・I had a gland. When precipitant gold is added, the gel porous granular product is 71L precipitated with methylchlorohexanes, chlorohekilinol, etc., and when n-butanol is used, it becomes opaque. A granular product of one-dimensional type was produced. Naoko Near 1
As a result of infrared absorption spectrum measurement of these products, the same spectrum as that of Example 1 was obtained, and it was confirmed that the product was a copolymer.

6) The same method as in 1) was carried out with hydroxamic acid 1 to obtain a cogyamic acid type chelate resin.
ml! f Toluene After soaking with methanol and washing with water, fill a column with an inner diameter of 3 crnl, and add natural filtered water at a temperature of 25 °C and a flow rate of 65 ml.

Water was passed upward at a rate of 1/min (SV = 390 hr')7, and a uranium adsorption experiment was conducted. At predetermined intervals, the adsorption cellar was removed and the amount of uranium adsorbed was determined using a wide point tip.

The complete table and one figure are shown as the results.

The uranium adsorbed to this resin is mineral acid (hydrochloric acid, sulfuric acid) V.
? :, more easily attached and detached.

Example 2 An adsorption experiment was carried out from seawater for 26 days under the conditions shown in Example 1.
After drying in the air, the adsorbed elements were qualitatively analyzed using fluorescent X-ray method. As a result, nickel, copper, zinc, and strontium were considered to be metals. It is clear that the resin of the present invention exhibits high selectivity for transition metals and uranium, and is particularly capable of recovering uranium from irrigation water.

In Reference Example 2, the metal adsorption performance was 11 times as high as that of 11 times.

[Brief explanation of drawings]

Figure (Bow Example 1) shows the relationship between the adsorption time and the amount of uranium adsorbed in the uranium. Fiber and Polymer Materials Research Institute, Agency of Industrial Science and Technology, 1-1-4 Higashi, Yatabe-cho, Tsukuba-gun, Prefecture

Claims (1)

[Scope of Claims] 1. A method for recovering trace metal ions, characterized in that a chelate resin having a dihydroxamic acid residue and maloni is used as an adsorbent in recovering the trace metal ions from an aqueous solution containing the metal ions. Collection method. 2. Aqueous solutions containing trace metal ions can be used in seawater, mine drainage,
The method according to claim 1, wherein the aqueous solution contains nuclear power plant wastewater and spent nuclear fuel. 3. The method according to claim 1 or 2, wherein the trace metal ion is a transition metal, ranknide series, or actinide series metal ion.