JP5929290B2 - Objective metal ion adsorbent and method for producing the same - Google Patents

Description

  The present invention relates to a target metal ion adsorbent containing a solid organophosphorus compound and a method for producing the same.

Metal elements, in particular rare earth elements, are substances that support the cutting-edge industry in Japan, and further demand is expected to expand in the future. However, in recent years, the vulnerability of the supply structure has become clear. One measure for ensuring a stable supply is recycling from process waste and waste products in the manufacturing process.
However, rare earth elements are often used in a mixture, and since the properties of each element are similar, they are very difficult to separate from each other and are hardly recycled.
Typical conventional techniques used for separation and purification of metal ions include (1) solvent extraction (see Non-Patent Document 1, Non-Patent Documents 2 and 3), and (2) ion exchange method (Patent Documents 1 and 2). 3), (3) impregnating resin method (Non-patent document 3, Non-patent document 4).

(1) The solvent extraction method is a method in which ions to be separated dissolved in an aqueous solution are selectively extracted into an organic solvent, and then back-extracted again into an aqueous solution phase. The selectivity is borne by the extraction reagent in the organic solvent. This method has been applied to many metal ion separation systems, and there are many types of extraction reagents that have been put into practical use industrially. For example, organic phosphorus compounds such as 2-Ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) and Bis-2- (ethylhexyl) phosphoric acid (D2EHPA) exist as extraction reagents most suitable for rare earth metals.
However, the solvent extraction method has a problem that a large amount of organic solvent and energy are required for its implementation, and the implementation apparatus becomes large. In particular, when this method is applied to the separation of rare earth element ions, more than one hundred processes are required, and a larger amount of organic solvent, energy, and a large facility are required than other metal ion separation / recovery methods.

(2) The ion exchange method is a method in which a target metal ion is adsorbed on an ion exchange resin and then separated by selective desorption.
However, this method has a problem that continuous processing is impossible and it takes time and cost to regenerate and replace the resin.

(3) The impregnation resin method is a method in which a porous polymer is impregnated with the extraction reagent used in the solvent extraction method.
However, in this method as well as the solvent extraction method, since the extraction reagent impregnated in the porous polymer is a liquid, the extraction reagent dissolves into the applied solution system, and the solution system is deteriorated. Let Therefore, there is a problem in durability in repeated use. Furthermore, the ratio of the extraction reagent that can be impregnated into the porous polymer is 50% at the maximum, that is, the portion effective for the metal ion adsorption is also at most half.

In addition to these three representative methods, development examples of novel metal ion adsorbents have been reported for the purpose of separating target metal ions to be separated with high selectivity (Non-Patent Documents). However, the synthesis method is complicated and the starting materials for synthesis are expensive.
Therefore, there is no satisfactory target metal ion adsorbent that can be manufactured at low cost and high versatility, can be easily and efficiently manufactured, and can be used repeatedly. Currently.

US Pat. No. 5,019,362 US Pat. No. 4,898,719 US Pat. No. 4,965,053

Yanliang Wang, Wuping Liao, Deqian Li, “A solvent extraction processwith mixture of CA12 and Cyanex272 for the preparation of high purity yttriumoxide from rare earth ores”, Separation and Purification Technology, Elsevier, vol.82, pp.197-201, 2011 . Weiwei Wang, Chu Yong Cheng, “Separation and purification of scandium by solvent extraction and related technologies: a review”, J. Chem. Technol. Biotechnol., Society of Chemical Industry, vol.86, pp.1237-1246, 2011. Chao-Feng Li, Xian-Hua Li, Qiu-Li Li, Jing-Hui Guo, Xiang-Hui Li, Tao Liu, “An evaluation of a single-step extraction chromatography separationmethod for Sm-Nd isotope andlysis of micro-samples of silicate rocks by high-sensitivity thermal ionization mass spectrometry ”, Analytica Chimica Acta, Elsevier, vol.706, pp.297-304, 2011. Korovin V, Shestak Y, PogorelovY and Cortina JL, “Solid polymeric extractants (TVEX): synthesis, extraction characterization and applications for metal extraction processes.” Solvent Extraction and LiquidMembranes: Fundamentals and Applications in New Materials, Aguilar M. and Cortina JL. CRCPress , Boca Raton, pp. 261-300, 2008. Keisuke Ohto, Takashi Matsufuji, Tomoaki Yonezawa, Masahiro Tanaka, Hidetaka Kawakita, Tatsuya Oshima, “Preorganized, cone-conformational calix [4] arenepossessing four propylenephosphonic acids with high extraction ability and separation efficiency for trivalent rare earth elements”, J. Incl. Phenom .Macrocycl. Chem., Springer, vol.71, pp489-497 (2011)

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention can carry out the separation of the target metal ion contained in the solution with low cost and high versatility, can be easily and efficiently produced, and can be used repeatedly. An object of the present invention is to provide a metal ion adsorbent and a method for producing the same.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and obtained the following knowledge. That is, when a metal complex containing a liquid organophosphorus compound used as the extraction reagent is obtained as a solid substance, the solid substance itself maintains the target metal ion adsorption performance. The whole can be used as an adsorbent for the target metal ion. Therefore, when separating the target metal ion, a large amount of organic solvent is not required as in the solvent extraction method, and more than the impregnating resin method supporting the liquid extraction reagent, the The ratio of the extraction reagent is high, and the loss of the extraction reagent is small.
Preparation of the solid adsorbent can be easily performed by appropriately selecting a solution system capable of generating a precipitate of the metal complex, and a method for separating and recovering target metal ions using the solid extraction reagent Can be the most powerful means in the field of recycling metals containing rare earth elements as a new method for separating and recovering target metal ions following the solvent extraction method, the ion exchange method, and the impregnation resin method.

The present invention is based on the above knowledge, and means for solving the above problems are as follows. That is,
<1> viewed contains a metal complex containing solid organic phosphorus compounds, the organic phosphorus compound is Bis (2-ethylhexyl) phosphoric acid , 2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester, and, Bis (2, 4,4-trimethylpentyl) phosphinic acid, the target metal ion adsorbent characterized by the above-mentioned .
< 2 > The target metal ion adsorbent according to <1 >, wherein the metal forming the metal complex is any one of Fe, Dy, La, In, and Y.
< 3 > The target metal ion adsorbent according to any one of <1> to < 2 >, further including a hydrophilicity-improving polymer that improves the hydrophilicity of the metal complex.
< 4 > The target metal ion adsorbent according to < 3 >, wherein the hydrophilicity-improving polymer is any one of polymethyl methacrylate, polyacrylonitrile, and a copolymer containing constituent units of these monomers.
< 5 > The target metal ion adsorbent according to < 4 >, wherein the hydrophilicity-improving polymer is polymethyl methacrylate.
< 6 > The target metal ion adsorbent according to < 5 >, wherein the polymethyl methacrylate has a weight average molecular weight of 1,000 to 150,000,000.
< 7 > The metal ion adsorbent according to any one of < 3 > to < 6 >, wherein the content ratio of the metal complex and the hydrophilic polymer and the metal complex / hydrophilic polymer is 10 to 100 by mass ratio.
< 8 > A metal-containing complex containing a liquid organophosphorus compound is contained in a mixed solution of two or more liquids to generate a precipitate containing the metal complex, and the metal from the precipitate seen containing a metal ion adsorbent obtaining step of obtaining a metal ion adsorbent comprising a complex, wherein the organic phosphorus compound is Bis (2-ethylhexyl) phosphoric acid , 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and, A method for producing a target metal ion adsorbent characterized by being selected from any of Bis (2,4,4-trimethylpentyl) phosphonic acid .
< 9 > The method for producing a target metal ion adsorbent according to < 8>, wherein the metal forming the metal complex is any one of Fe, Dy, La, In, and Y.
< 10 > The precipitate formation step includes at least a metal complex and a hydrophilicity-improving polymer that improves the hydrophilicity of the metal complex in a mixed solution, and the composite coagulation including the metal complex and the hydrophilicity-improving polymer. The method for producing a target metal ion adsorbent according to any one of < 8 > to < 9 >, which is a step of generating a precipitate as an aggregate.
< 11 > In the precipitate generation step, the mixed solution in which the hydrophilicity improving polymer is dissolved is heated to obtain a colloidal solution in which colloidal particles of the hydrophilicity improving polymer are dispersed, and then at least a metal complex is added to the colloidal solution. The manufacturing method of the target metal ion adsorption agent as described in said < 10 > which is a process.
< 12 > The target metal ion according to any one of < 10 > to < 11 >, wherein the hydrophilicity-improving polymer is any one of polymethylmethacrylate, polyacrylonitrile, and a copolymer containing structural units of these monomers. Production method of adsorbent.
< 13 > The method for producing a target metal ion adsorbent according to < 12 >, wherein the hydrophilicity improving polymer is polymethyl methacrylate.
< 14 > The method for producing a target metal ion adsorbent according to < 13 >, wherein the polymethyl methacrylate has a weight average molecular weight of 1,000 to 150,000,000.
< 15 > The method for producing a target metal ion adsorbent according to any one of < 8 > to < 14 >, wherein the mixed solution is a mixed solution of an organic solvent in which the metal complex is soluble and water.
< 16 > The method for producing a target metal ion adsorbent according to < 15 >, wherein the organic solvent is one of alcohol and ketone.
< 17 > The method for producing a target metal ion adsorbent according to < 16 >, wherein the mixed solvent is an aqueous ethanol solution having a concentration of 65% by volume or more and less than 100% by volume.

  According to the present invention, the above-mentioned problems in the prior art can be solved, and the separation of the target metal ion contained in the solution can be carried out with low cost and high versatility, and also easily and efficiently. It is possible to provide a target metal ion adsorbent that can be produced and that can be used repeatedly, and a method for producing the same.

10 is a graph showing the particle size distribution of colloids in Example 9. It is a graph which shows the particle size distribution of the colloid in Example 10-1. It is a graph which shows the particle size distribution of the colloid in Example 11-1. It is a graph which shows the particle size distribution of the colloid in Example 11-2. It is a graph which shows the particle size distribution of the colloid in Example 11-3. It is a graph which shows the particle size distribution of the colloid in Example 14. FIG. 2 is an electron micrograph of a target metal ion adsorbent according to Example 1. FIG. 2 is an XRD spectrum of a target metal ion adsorbent according to Example 1. FIG. It is the АTRFT-IR spectrum of the organic phase in Example 1 (after centrifugation) and the target metal ion adsorbent. It is the АTRFT-IR spectrum of the organic phase in Example 1 (after centrifugation) and the target metal ion adsorbent. 6 is an electron micrograph of a target metal ion adsorbent according to Example 9. 10 is an АTRFT-IR spectrum of a target metal ion adsorbent according to Example 9. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-1. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-2. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-3. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-4. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-5. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-6. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-7. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-8. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-9. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-10. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-11. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-12. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 10-13. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 11-1. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 11-2. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 11-3. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 12-1. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 12-2. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 12-3. It is an АTRFT-IR spectrum of the target metal ion adsorbent according to Example 14. It is the table | surface which showed the relationship between the Fe ion density | concentration in Example 1, 7-1 to 7-5, and the yield of the target metal ion adsorption agent obtained. It is the graph which plotted the relationship shown by FIG. It is the graph which plotted the relationship between the density | concentration of Fe ion and Dy ion adsorption amount in Example 1, 7-1 to 7-5. FIG. 30 is a table showing the relationship between the ethanol concentration in an aqueous ethanol solution and the yield. FIG. 31 is a graph in which the numerical values shown in FIG. 30 are plotted. It is the graph which showed the relationship between the density | concentration of the mixed solution in Examples 8-1 to 8-5, and the yield of the target metal ion adsorption agent obtained. It is the graph which plotted the relationship shown by FIG.

(Target metal ion adsorbent)
The object metal ion adsorbent of the present invention contains a metal complex containing a solid organophosphorus compound, and if necessary, contains other compounds such as a hydrophilicity improving polymer.

<Metal complex>
The metal complex is in a solid state. The extraction reagent used in the solvent extraction method or impregnation resin method is a liquid, and the extraction reagent easily deteriorates the solution system in the separation process of the separation target metal contained in the solution system, but includes the metal complex. The metal ion adsorbent is in a solid state while maintaining the metal ion adsorption ability of the extraction reagent.
Note that in this specification, the solid state means a solid at least at room temperature and in an air atmosphere.

  The target metal ion adsorbed by the target metal ion adsorbent, that is, the metal to be separated can include all metals, depending on the type of the organophosphorus compound selected as the extraction reagent. Including rare earth metals that have been considered difficult.

-Organic phosphorus compounds-
The organophosphorus compound is not particularly limited as long as it is a compound that forms the metal complex and becomes a solid, and can be appropriately selected according to the purpose. Commercially available products that have been used as conventional metal ion extraction reagents can be used. Including various organic phosphorus compounds.
For example, examples of the structure of the organic phosphorus compound include compounds represented by the following structural formula (1).

However, in said structural formula (1), R < ¹ > shows either a hydroxyl group, an alkoxy group, and an alkyl group, and R < ² > and R < ³ > show either an alkoxy group and an alkyl group.

  Specific examples of the organic phosphorus compound include, for example, bis (2-ethylhexyl) hydrogen phosphate; Bis (2-ethylhexyl) phosphoric acid (the following structural formula (2), hereinafter also referred to as D2EHPA), 2-Ethylhexyl. phosphonic acid mono-2-ethylhexyl ester (the following structural formula (3), hereinafter also referred to as PC-88A), Bis (2,4,4-trimethylpropyl) phosphonic acid (the following structural formula (4), hereinafter also referred to as CYANEX272) ) And Tributylphosphate (the following structural formula (5), hereinafter also referred to as TBP).

-Metals that form metal complexes-
The metal that forms the metal complex, that is, the complex-forming metal is not particularly limited as long as it is a metal that can form a solid metal complex using the organophosphorus compound as a ligand. For example, Fe, Dy, La , In, Y and the like.

Although there is no restriction | limiting in particular as content rate of the said organophosphorus compound and the said complex formation metal in the said metal ion adsorption agent, ie, a complex formation metal / organophosphorus compound, 0.00005-0.15 are preferable by mass ratio.
When the mass ratio is less than 0.00005, it is difficult to obtain a sufficient amount of the metal ion adsorbent, and when it exceeds 0.15, the metal complex before precipitation prepared as an organic phase is separated from the aqueous phase. May be difficult to do.

<Hydrophilicity improvement polymer>
When the target metal ion adsorbent of the metal complex is used, the target metal ion adsorbent is likely to be hydrophobic, and the target metal ion adsorbent is immersed in a solution system containing the target metal ion. The adsorptivity of ions may be lowered. Therefore, for the purpose of improving the wettability of the target metal ion adsorbent to increase the contact area between the target metal ion adsorbent and the solution system, and further improving the target metal ion adsorbability, A hydrophilicity-improving polymer that improves the hydrophilicity of the ion adsorbent can be included in the target metal ion adsorbent.

The hydrophilicity-improving polymer is not particularly limited as long as it improves the wettability of the target metal ion adsorbent, and can be appropriately selected according to the purpose. Polymethylmethacrylate and polyacrylonitrile alone, and copolymers containing these constitutional units are preferred.
Among them, the polymethyl methacrylate is preferable from the viewpoint of being able to form a colloid that is stable for a long time.

Although there is no restriction | limiting in particular as a weight average molecular weight (Mw) of the said polymethyl methacrylate, 1,000-150,000,000 are preferable, 35,000-996,000 are more preferable, 15,000-350, 000 is particularly preferred.
When the weight average molecular weight is less than 1,000, a stable colloid may not be obtained. When the weight average molecular weight exceeds 150,000,000, the solubility is low, and further a colloid may not be formed.

Although there is no restriction | limiting in particular as content rate of the said metal complex and the said hydrophilicity improvement polymer in the said target metal ion adsorption agent, ie, a metal complex / hydrophilic polymer, 0.01-50 are preferable by mass ratio.
If the mass ratio is less than 0.01, the adsorption amount of the target metal ion may be small, and if it exceeds 50, the effect of the hydrophilic polymer may not be sufficiently exhibited.

<Other compounds>
There is no restriction | limiting in particular as long as the said other compound does not impair the function which the said target metal ion adsorption agent has, It can select suitably according to the objective.

  Although there is no restriction | limiting in particular as the manufacturing method of the said target metal ion adsorbent demonstrated above, It can manufacture easily at low cost with the manufacturing method of the target metal ion adsorbent of this invention demonstrated below.

(Target metal ion adsorbent production method)
The method for producing a target metal ion adsorbent of the present invention includes at least a precipitate generation step and a target metal ion adsorbent acquisition step, and includes other steps that are performed as necessary.

<Precipitate generation process>
The precipitate generation step is a step of generating a precipitate containing the metal complex by containing a metal complex containing a liquid organophosphorus compound in a mixed solution of two or more liquids.

  The organophosphorus compound is not particularly limited as long as it forms the metal complex and forms a precipitate, and can be appropriately selected according to the purpose, and is applied to the metal ion adsorbent of the present invention. Organic phosphorus compounds.

  The metal that forms the metal complex, that is, the complex-forming metal is not particularly limited as long as it is a metal that forms a precipitate of the metal complex in the mixed solution, and can be appropriately selected according to the purpose. The complex-forming metal applied to the object metal ion adsorbent of the present invention is mentioned.

  There is no restriction | limiting in particular as a preparation method of the said liquid metal complex, According to the objective, it can select suitably, A conventionally well-known method can be applied. For example, after the liquid organophosphorus compound is added to an aqueous solution in which the complex forming metal is dissolved, the complex forming metal ions (complex forming metal ions) are moved to the organic phase of the organophosphorus compound by stirring. Thus, the metal complex can be prepared by liquid / liquid phase separation of the organic phase and the water phase. The organic phase can be easily extracted from the water phase by a method such as centrifugation, and the extracted organic phase can be used as the liquid metal complex.

The mixed solvent is not particularly limited as long as the metal complex precipitate is generated, and can be appropriately selected according to the purpose. For example, a mixed solution of one organic solvent and another organic solvent, water And a mixed solution of an organic solvent and the like.
Among these, from the viewpoint of easy preparation, a mixed solution of water and an organic solvent is preferable.
The mixed solvent is not limited to a mixed solution of these two liquids, and may be a mixed solution of three or more liquids.
In addition, these mixed solvents are preferably those in which the hydrophilicity-improving polymer is soluble and the hydrophilic polymer forms a colloid from the viewpoint of simplifying the production process.

  The organic solvent in the mixed solution is not particularly limited as long as the precipitate of the metal complex is generated, but can be easily obtained, and from the viewpoint of keeping the environmental load low, alcohols and ketones can be used. Among them, alcohols having 1 to 5 carbon atoms and ketones having 3 to 4 carbon atoms are preferable, and ethanol is particularly preferable.

When the ethanol aqueous solution is selected as the mixed solution, the ethanol concentration may be 65% by volume to less than 100% by volume, and preferably 75% by volume to 90% by volume.
When the ethanol concentration is less than 65% by volume, the precipitate is hardly generated, and when it is 100% by volume (single solution), the precipitate cannot be generated.
In addition, when the ethanol concentration is less than 75% by volume or more than 90% by volume, the generation efficiency of the precipitate may be lowered.
On the other hand, when the ethanol concentration is within a preferable range, not only the generation efficiency of the precipitate is improved, but also when the hydrophilicity improving polymer described later is used, the hydrophilicity improving polymer is solubilized in the ethanol aqueous solution. The target metal ion adsorbent can be produced with high efficiency.

The method for generating the precipitate using the mixed solvent is not particularly limited. For example, the liquid metal complex is added to a mixed solution of two or more liquids in advance and stirred to generate the precipitate. Alternatively, after dissolving the metal complex in one kind of liquid, another liquid may be added and stirred to form the precipitate.
In addition, when it replaces with the said mixed solution and only 1 type of liquid is used, the said precipitate will not be produced | generated but preparation of the said target metal ion adsorption agent will become difficult.

There is no restriction | limiting in particular as said hydrophilic polymer, It can apply according to the objective, The hydrophilic polymer applied to the objective metal ion adsorption agent of the said this invention is mentioned.
When producing the target metal ion adsorbent containing the hydrophilic polymer, there is no limit to the method of performing the step, but from the viewpoint of simplifying the production process, the precipitate generation step, at least the metal complex, It is preferable that the hydrophilicity improving polymer is contained in the mixed solution and the precipitate is formed as a composite aggregate including the metal complex and the hydrophilicity improving polymer.
In addition, in the process of precipitating the target metal ion adsorbent simultaneously with the hydrophilicity improving polymer, the adsorbent to be produced can be easily formed by appropriately selecting the shape of the container used for the reaction.

Further, when the target metal ion adsorbent containing the hydrophilic polymer is produced, the precipitate generation step is performed by heating the mixed solution in which the hydrophilicity improving polymer is dissolved, and colloid of the hydrophilicity improving polymer. It is more preferable to carry out as a step of adding at least the metal complex to the colloid solution after preparing a colloid solution in which particles are dispersed. The colloidal solution can be generated even under conditions where the temperature of the mixed solution in which the hydrophilicity improving polymer is dissolved is not increased, and the temperature increase is not necessarily a condition for generating the colloidal solution.
When the mixed solution is colloidalized, the target metal ion adsorbability of the target metal ion adsorbent obtained can be improved. The reason for this is not necessarily clear, but when the metal complex aggregates and precipitates, the hydrophilicity-improving polymer easily forms a precipitate at the same time. This is presumably because the contact area between the adsorption site for adsorbing the target metal ion and the aqueous solution containing the target metal ion increases.

The temperature for raising the temperature of the mixed solution is not particularly limited as long as the colloidal solution is prepared. For example, when the hydrophilicity improving polymer is polymethyl methacrylate, about 30 ° C. to 60 ° C. is preferable. . Below 30 ° C., the solubility of the hydrophilicity-improving polymer is small, and the effect of the hydrophilicity-improving polymer may not be exhibited. At 60 ° C. or more, the solubility of the hydrophilicity-improving polymer is large. A large amount of the hydrophilicity-improving polymer is precipitated, which may result in a gel.
Further, the timing of adding the liquid metal complex to the colloidal solution may be as soon as the temperature starts to drop after the temperature is raised to the target temperature to form the colloid, or until the temperature once drops to room temperature. It may be after being left. However, depending on conditions, even when a solution in which the colloidal particles are sufficiently dispersed is used, the colloidal particles are not mixed with the metal complex and aggregated at the same time. As a result, the adsorption amount of the target metal ion is improved. Sometimes it doesn't.

<Target metal ion adsorbent acquisition process>
The target metal ion adsorbent acquisition step is a step of acquiring a target metal ion adsorbent containing the metal complex from the precipitate.

  As a specific implementation method of the target metal ion adsorbent acquisition step, as long as the target metal ion adsorbent can be acquired from the precipitate, there is no particular limitation, it can be appropriately selected according to the purpose, for example, Examples include a method of obtaining the precipitate precipitated in the mixed solvent by suction filtration.

<Other processes>
There is no restriction | limiting in particular as long as the said other process does not prevent implementation of the manufacturing method of the target metal ion adsorption agent of this invention, According to the objective, a required process can be selected suitably.

  In the following, a more specific production method of the metal ion adsorbent, characteristics of the produced target metal ion adsorbent, and details of the utilization method will be described as examples, but the technical idea of the present invention is, It is not limited to these examples.

Example 1
5 mL of bis (2-ethylhexyl) phosphoric acid (D2EHPA; manufactured by Aldrich) was added to an 80 mM FeCl ₃ aqueous solution and stirred to move Fe ions (complexing metal ions) in the aqueous solution to the organic phase (D2EHPA phase). .
This solution was centrifuged at 8,000 rpm for 30 minutes, and then the organic phase (D2EHPA-Fe complex) was taken out.
1 mL of the extracted organic phase was added to 5 mL of 80 vol% ethanol aqueous solution and stirred, and then allowed to stand so that precipitation as an aggregate of D2EHPA-Fe complex occurred.
This precipitate was suction filtered through a membrane made of polytetrafluoroethylene (PTFE) and dried to produce the target metal ion adsorbent according to Example 1.
When the organic phase in which the Fe ions were transferred was diluted with ethanol and the Fe ion concentration was measured by atomic absorption, the Fe ion concentration in the organic phase was 0.45 wt%.
Further, the weight of the obtained target metal ion adsorbent was measured and found to be 0.088 g.

(Example 2; complex-forming metal species (complex-forming metal ion species))
<Example 2-1>
In Example 1, the target metal ion adsorbent according to Example 2-1 was produced in the same manner as in Example 1 except that 10 mL of 50 mM FeCl ₂ aqueous solution was used instead of the FeCl ₃ aqueous solution.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.093 g.

<Example 2-2>
In Example 1, a target metal ion adsorbent according to Example 2-2 was produced in the same manner as in Example 1 except that 10 mL of 50 mM DyCl ₃ aqueous solution was used instead of the FeCl ₃ aqueous solution.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.093 g.

<Example 2-3>
In Example 1, the target metal ion adsorbent according to Example 2-3 was produced in the same manner as in Example 1 except that 10 mL of 50 mM LaCl ₃ aqueous solution was used instead of the FeCl ₃ aqueous solution.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.064 g.

<Example 2-4>
In Example 1, the target metal ion adsorbent according to Example 2-4 was produced in the same manner as in Example 1 except that 10 mL of 50 mM In (NO ₃ ) ₃ aqueous solution was used instead of FeCl ₃ aqueous solution. did.
In addition, it was 0.16g when the weight of the obtained target metal ion adsorbent was measured.

<Example 2-5>
In Example 1, the target metal ion adsorbent according to Example 2-5 was produced in the same manner as in Example 1 except that 10 mL of 50 mM YCl ₃ aqueous solution was used instead of the FeCl ₃ aqueous solution.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.10 g.

Example 3 Precipitate Formation Solution Species
<Example 3-1>
In Example 1, an 80 vol% 1-propanol aqueous solution was used in place of the 80 vol% ethanol aqueous solution, and the FeCl ₃ aqueous solution concentration was changed from 80 mM to 66 mM, so that the Fe ion concentration in the organic phase (D2EHPA) was 0.00. A target metal ion adsorbent according to Example 3-1 was produced in the same manner as in Example 1 except that the content was 37 wt%.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.020 g.

<Example 3-2>
In Example 3-1, the target metal ion adsorption according to Example 3-2 was performed in the same manner as in Example 3-1, except that an 80 vol% 2-propanol aqueous solution was used instead of the 80 vol% 1-propanol aqueous solution. An agent was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.045 g.

<Example 3-3>
In Example 3-1, the target metal ion adsorbent according to Example 3-3 was used in the same manner as in Example 3-1, except that an 80 vol% acetone aqueous solution was used instead of the 80 vol% 1-propanol aqueous solution. Manufactured.
In addition, when the weight of the obtained metal ion adsorbent was measured, it was 0.055 g.

<Example 3-4>
In Example 3-1, the target metal ion according to Example 3-4 was used in the same manner as in Example 3-1, except that a 95 vol% 1-butyl alcohol aqueous solution was used instead of the 80 vol% 1-propanol aqueous solution. An adsorbent was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.035 g.

(Example 4: concentration of mixed solution)
<Example 4-1>
In Example 1, instead of the 80 vol% ethanol aqueous solution, the 65 vol% ethanol aqueous solution was used, and the FeCl ₃ aqueous solution concentration was changed from 80 mM to 66 mM, and the Fe ion concentration in the organic phase (D2EHPA) was 0.37 wt%. A target metal ion adsorbent according to Example 4-1 was produced in the same manner as in Example 1 except that the above was achieved.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.0033 g.

<Example 4-2>
In Example 4-1, a target metal ion adsorbent according to Example 4-2 was produced in the same manner as in Example 4-1, except that a 70 vol% ethanol aqueous solution was used instead of the 65 vol% ethanol aqueous solution. .
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.035 g.

<Example 4-3>
In Example 4-1, a target metal ion adsorbent according to Example 4-3 was produced in the same manner as in Example 4-1, except that a 75 vol% ethanol aqueous solution was used instead of the 65 vol% ethanol aqueous solution. .
In addition, it was 0.048g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 4-4>
In Example 4-1, a target metal ion adsorbent according to Example 4-4 was produced in the same manner as in Example 4-1, except that an 85 vol% ethanol aqueous solution was used instead of the 65 vol% ethanol aqueous solution. .
In addition, it was 0.046g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 4-5>
In Example 4-1, a target metal ion adsorbent according to Example 4-5 was produced in the same manner as in Example 4-1, except that a 90 vol% ethanol aqueous solution was used instead of the 65 vol% ethanol aqueous solution. .
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.039 g.

<Comparative Example 1-1>
In Example 1, production of the target metal ion adsorbent according to Comparative Example 1-1 was attempted in the same manner as in Example 1 except that water was used instead of the 80 vol% ethanol aqueous solution.
However, the D2EHPA-Fe complex was separated from water in a liquid / liquid phase, and no precipitate was observed.

<Comparative Example 1-2>
In Example 1, production of the target metal ion adsorbent according to Comparative Example 1-1 was tried in the same manner as in Example 1 except that ethanol was used instead of the 80 vol% ethanol aqueous solution.
However, the D2EHPA-Fe complex was completely dissolved in ethanol, and no precipitate was observed.

(Example 5)
In Example 1, instead of adding and stirring the organic phase (D2EHPA-Fe complex) in an 80 vol% ethanol aqueous solution, the organic phase (D2EHPA-Fe complex) was dissolved in 100% ethanol in advance, The target metal ion adsorbent according to Example 5 was produced in the same manner as in Example 1 except that water was added and stirred so as to obtain an 80 vol% ethanol aqueous solution. The Fe ion concentration in D2EHPA was 0.37 wt%.
In addition, it was 0.048g when the weight of the obtained target metal ion adsorption agent was measured.

(Example 6)
In Example 1, D2EHPA was added to an FeCl ₃ aqueous solution and stirred, and instead of moving Fe ions in the aqueous solution to the organic phase, 0.063 g of FeCl ₃ was mixed with 5 mL of D2EHPA and stirred. The target metal ion adsorbent according to Example 6 was produced in the same manner as in Example 1 except that was mixed with 80 vol% ethanol aqueous solution. The Fe ion concentration in D2EHPA was 0.80 wt%.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.045 g.

(Example 7: Concentration of complexing metal ions)
<Example 7-1>
In Example 1, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 8.8 mM, and the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.051 wt%. The target metal ion adsorbent according to Example 7-1 was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.0084 g.

<Example 7-2>
In Example 1, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 66 mM, and the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.37 wt%. The target metal ion adsorbent according to 7-2 was produced.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.055 g.

<Example 7-3>
In Example 1, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 135 mM, and the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.76 wt%. The target metal ion adsorbent according to 7-3 was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.12 g.

<Example 7-4>
In Example 1, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 249 mM, and the Fe ion concentration in the organic phase (D2EHPA) was 1.4 wt%. The target metal ion adsorbent according to 7-4 was produced.
In addition, it was 0.16g when the weight of the obtained target metal ion adsorbent was measured.

<Example 7-5>
In Example 1, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 373 mM, and the Fe ion concentration in the organic phase (D2EHPA) was 2.1 wt%. The target metal ion adsorbent according to 7-5 was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.19 g.

(Example 8: Mixing ratio of mixed solution and metal complex)
<Example 8-1>
In Example 1, 1 mL of the organic phase (D2EHPA-Fe complex) was added to 5 mL of 80 vol% ethanol aqueous solution, and 0.5 mL of the organic phase (D2EHPA-Fe complex) was added to 5 mL of 80 vol% ethanol aqueous solution. In the same manner as in Example 1 except that the FeCl ₃ aqueous solution concentration was changed from 80 mM to 250 mM and the Fe ion concentration in the organic phase (D2EHPA) was 1.4 wt%, Example 8-1 Such a target metal ion adsorbent was produced.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.13 g.

<Example 8-2>
In Example 8-1, adding 0.5 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution and adding 0.75 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution. Except having changed, it carried out similarly to Example 8-1, and manufactured the target metal ion adsorption agent which concerns on Example 8-2.
In addition, it was 0.20g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 8-3>
In Example 8-1, adding 0.5 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution and adding 1.25 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution. A target metal ion adsorbent according to Example 8-3 was produced in the same manner as in Example 8-1, except that the change was made.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.34 g.

<Example 8-4>
In Example 8-1, adding 0.5 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution and adding 1.5 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution. A target metal ion adsorbent according to Example 8-4 was produced in the same manner as in Example 8-1, except that the change was made.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.39 g.

<Example 8-5>
In Example 8-1, adding 0.5 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution and adding 1.75 mL of the organic phase (D2EHPA-Fe complex) to 5 mL of 80 vol% ethanol aqueous solution. A target metal ion adsorbent according to Example 8-5 was produced in the same manner as in Example 8-1, except that the change was made.
In addition, it was 0.45g when the weight of the obtained target metal ion adsorption agent was measured.

Example 9
In Example 1, instead of the 80 vol% ethanol aqueous solution, an 80 vol% ethanol aqueous solution in which polymethyl methacrylate (PMMA) having a weight average molecular weight (Mw) of 120,000 was stirred and dissolved at room temperature was used. And the FeCl ₃ aqueous solution concentration was changed from 80 mM to 76 mM so that the Fe ion concentration in the organic phase (D2EHPA) was 0.43 wt%. The target metal ion adsorbent was produced.
Here, the ethanol aqueous solution of PMMA in Example 9 was a colloidal solution in which PMMA was dispersed. FIG. 1 (a) shows the particle size distribution of the obtained colloid.
Moreover, the density | concentration in the ethanol aqueous solution of PMMA was 0.18 wt%.
In the production of the target metal ion adsorbent according to Example 9, it was confirmed that the D2EHPA-Fe complex and PMMA formed a precipitate as a composite aggregate.
In addition, it was 0.061g when the weight of this objective metal ion adsorbent was measured.

Example 10 Colloid Solution Conditions
<Example 10-1>
In Example 9, instead of the ethanol aqueous solution of PMMA that was saturated and dissolved at room temperature, the ethanol aqueous solution of PMMA that was allowed to stand at room temperature after being heated to 30 ° C. was used, and the concentration of the FeCl ₃ aqueous solution was changed from 80 mM to 69 mM. A target metal ion adsorbent according to Example 10-1 was produced in the same manner as in Example 9 except that the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.39 wt%.
Here, the ethanol aqueous solution of PMMA in Example 10-1 was a colloidal solution in which PMMA was dispersed. FIG. 1B shows the particle size distribution of the obtained colloid.
Moreover, the density | concentration in the ethanol aqueous solution of PMMA was 0.29 wt%.
In addition, it was 0.096g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 10-2>
In Example 9, instead of using an ethanol aqueous solution of PMMA saturated at room temperature, an ethanol aqueous solution of PMMA (colloidal solution) that was allowed to stand at room temperature after being heated to 40 ° C. and the concentration of the FeCl ₃ aqueous solution were changed. The target metal ion adsorbent according to Example 10-2 in the same manner as in Example 9 except that the Fe ion concentration in the organic phase (D2EHPA) was changed to 809% to 123mM to be 0.69wt%. Manufactured.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.77 wt%.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.15 g.
FIG. 1B shows the particle size distribution of the colloid in Example 10-2.

<Example 10-3>
In Example 9, in place of the ethanol aqueous solution of PMMA saturated at room temperature, an ethanol aqueous solution of PMMA (colloidal solution) that was allowed to stand at room temperature after being heated to 50 ° C. and the concentration of the FeCl ₃ aqueous solution were changed. The target metal ion adsorbent according to Example 10-3 in the same manner as in Example 9 except that the Fe ion concentration in the organic phase (D2EHPA) was changed to 80mM to 66mM to be 0.38wt%. Manufactured.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 1.2 wt%.
Moreover, it was 0.093g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 10-4>
In Example 9, instead of the ethanol aqueous solution of PMMA saturated at room temperature, an ethanol aqueous solution of PMMA (colloidal solution) that was heated to 40 ° C. and allowed to stand at room temperature was used, and the weight average molecular weight was 120,000. Instead of PMMA, PMMA having a weight average molecular weight of 35,000 was used, and the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 123 mM so that the Fe ion concentration in the organic phase (D2EHPA) became 0.69 wt%. A target metal ion adsorbent according to Example 10-4 was produced in the same manner as in Example 9 except that the above procedure was performed.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.45 wt%.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.11 g.

<Example 10-5>
In Example 9, instead of the ethanol aqueous solution of PMMA saturated at room temperature, an aqueous ethanol solution (colloidal solution) of PMMA that was heated to 40 ° C. and allowed to stand at room temperature was used, and the weight average molecular weight was 120,000. The PMMA having a weight average molecular weight of 350,000 was used instead of PMMA, and the FeCl ₃ aqueous solution concentration was changed from 80 mM to 123 mM, so that the Fe ion concentration in the organic phase (D2EHPA) became 0.69 wt%. A target metal ion adsorbent according to Example 10-5 was produced in the same manner as in Example 9 except for the above.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.055 wt%.
Moreover, it was 0.13g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 10-6>
In Example 9, instead of the ethanol aqueous solution of PMMA that was saturated and dissolved at room temperature, the ethanol aqueous solution of PMMA that started to decrease in temperature after being heated to 40 ° C. was used, and the concentration of the FeCl ₃ aqueous solution was changed from 80 mM. The target metal ion adsorbent according to Example 10-6 was produced in the same manner as in Example 9 except that the Fe ion concentration in the organic phase (D2EHPA) was changed to 123 mM so that the Fe ion concentration was 0.69 wt%. did.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.74 wt%.
Moreover, it was 0.14g when the weight of the obtained target metal ion adsorbent was measured.

<Example 10-7>
In Example 9, instead of the ethanol aqueous solution of PMMA that was saturated and dissolved at room temperature, the PMMA ethanol aqueous solution that started to decrease in temperature after being heated to 60 ° C. was used, and the PMMA having a weight average molecular weight of 120,000. Instead of using PMMA having a weight average molecular weight of 350,000, and changing the concentration of the FeCl ₃ aqueous solution from 80 mM to 123 mM, the Fe ion concentration in the organic phase (D2EHPA) becomes 0.69 wt%. Except that, the target metal ion adsorbent according to Example 10-7 was produced in the same manner as in Example 9.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 1.4 wt%.
Moreover, it was 0.19 g when the weight of the obtained target metal ion adsorbent was measured.

<Example 10-8>
In Example 9, instead of using an aqueous ethanol solution of PMMA that was saturated and dissolved at room temperature, a colloidal solution obtained by allowing the solution to stand at room temperature after being heated to 40 ° C. was used for 1 day except that an aqueous ethanol solution of PMMA was used. Produced the target metal ion adsorbent according to Example 10-8 in the same manner as in Example 9.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.11 g.

<Example 10-9>
In Example 9, in place of the ethanol aqueous solution of PMMA saturated and dissolved at room temperature, the colloidal solution obtained by allowing the mixture to stand at room temperature after being heated to 40 ° C. was used for 1 day, and an ethanol aqueous solution of PMMA was used. The target metal ion adsorbent according to Example 10-9 was produced in the same manner as in Example 9 except that PMMA having a weight average molecular weight of 35,000 was used instead of PMMA having a weight average molecular weight of 120,000. did.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.090 g.

<Example 10-10>
In Example 9, instead of using an ethanol aqueous solution of PMMA saturated at room temperature, a PMMA ethanol aqueous solution (colloidal solution) obtained by raising the temperature to 30 ° C. and leaving it at room temperature was used. Was used instead of PMMA having a weight average molecular weight of 996,000, and the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 41 mM, so that the Fe ion concentration in the organic phase (D2EHPA) was 0.00. A target metal ion adsorbent according to Example 10-10 was produced in the same manner as in Example 9 except that the content was 23 wt%.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.031 wt%.
Moreover, it was 0.061 g when the weight of the obtained target metal ion adsorbent was measured.

<Example 10-11>
In Example 9, instead of using an aqueous ethanol solution of PMMA saturated at room temperature, an aqueous ethanol solution (colloidal solution) of PMMA obtained by heating to 30 ° C. and standing at room temperature was used, and FeCl ₃ The purpose according to Example 10-11 is similar to Example 9 except that the concentration of the aqueous solution is changed from 80 mM to 41 mM so that the Fe ion concentration in the organic phase (D2EHPA) is 0.23 wt%. A metal ion adsorbent was produced.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 1.3 wt%.
Moreover, it was 0.096g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 10-12>
In Example 9, instead of using an ethanol aqueous solution of PMMA saturated at room temperature, a PMMA ethanol aqueous solution (colloidal solution) obtained by raising the temperature to 30 ° C. and leaving it at room temperature was used. Was replaced with 15,000 PMMA having a weight average molecular weight of 35,000, and the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 41 mM, so that the Fe ion concentration in the organic phase (D2EHPA) was 0.00. A target metal ion adsorbent according to Examples 10-12 was produced in the same manner as in Example 9, except that the content was 23 wt%.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 1.7 wt%.
Moreover, it was 0.064g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 10-13>
In Example 9, instead of using an ethanol aqueous solution of PMMA saturated at room temperature, a PMMA ethanol aqueous solution (colloidal solution) obtained by raising the temperature to 30 ° C. and leaving it at room temperature was used. Was replaced with 15,000 PMMA having a weight average molecular weight of 15,000, and the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 41 mM, so that the Fe ion concentration in the organic phase (D2EHPA) was 0.00. A target metal ion adsorbent according to Example 10-13 was produced in the same manner as in Example 9 except that the content was 23 wt%.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 2.8 wt%.
Moreover, it was 0.061 g when the weight of the obtained target metal ion adsorbent was measured.

Example 11: Molecular weight of polymer
<Example 11-1>
In Example 9, the PMMA having a weight average molecular weight of 120,000 was changed to the PMMA having a weight average molecular weight of 15,000, and the concentration of the FeCl ₃ aqueous solution was changed from 80 mM to 68 mM, so that Fe ions in the organic phase (D2EHPA) The target metal ion adsorbent according to Example 11-1 was produced in the same manner as in Example 9 except that the concentration was 0.38 wt%.
Here, the ethanol aqueous solution of PMMA in Example 11-1 was a colloidal solution in which PMMA was dispersed. FIG. 1 (c) shows the particle size distribution of the colloid obtained.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.086 wt%.
Moreover, it was 0.055 g when the weight of the obtained target metal ion adsorbent was measured.

<Example 11-2>
In Example 11-1, the target metal ion according to Example 11-2 was obtained in the same manner as in Example 11-1, except that PMMA having a weight average molecular weight of 15,000 was changed to PMMA having a weight average molecular weight of 35,000. An adsorbent was produced.
Here, the ethanol aqueous solution of PMMA in Example 11-2 was a colloidal solution in which PMMA was dispersed. FIG. 1 (d) shows the particle size distribution of the obtained colloid.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.017 wt%.
Moreover, it was 0.046g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 11-3>
In Example 11-1, the target metal ion according to Example 11-3 was obtained in the same manner as in Example 11-1, except that PMMA having a weight average molecular weight of 15,000 was changed to PMMA having a weight average molecular weight of 350,000. An adsorbent was produced.
Here, the ethanol aqueous solution of PMMA in Example 11-3 was a colloidal solution in which PMMA was dispersed. FIG. 1 (e) shows the particle size distribution of the obtained colloid.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.0088 wt%.
Moreover, it was 0.018 g when the weight of the obtained target metal ion adsorbent was measured.

<Example 11-4>
In Example 11-1, the target metal ion according to Example 11-4 was obtained in the same manner as in Example 11-1, except that PMMA having a weight average molecular weight of 15,000 was changed to PMMA having a weight average molecular weight of 996,000. An adsorbent was produced.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.0064 wt%.
Moreover, it was 0.017 g when the weight of the obtained target metal ion adsorption agent was measured.

Example 12: Various mixed solutions
<Example 12-1>
In Example 9, instead of the ethanol aqueous solution of PMMA saturated and dissolved at room temperature, the aqueous solution of PMMA having a weight average molecular weight of 350,000 was heated to 60 ° C. and then left at room temperature to obtain a gel And the concentration of the FeCl ₃ aqueous solution was changed from 80 mM to 68 mM so that the Fe ion concentration in the organic phase (D2EHPA) was 0.38 wt%. The target metal ion adsorbent according to Example 12-1 was produced.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.020 wt%.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.13 g.

<Example 12-2>
In Example 9, instead of the ethanol aqueous solution of PMMA that was saturated and dissolved at room temperature, the PMMA ethanol aqueous solution that had been heated to 40 ° C. and before reaching room temperature was used, and that the weight average molecular weight was 120,000. Instead of using PMMA having a weight average molecular weight of 350,000, and changing the concentration of the FeCl ₃ aqueous solution from 80 mM to 123 mM, the Fe ion concentration in the organic phase (D2EHPA) becomes 0.69 wt%. A target metal ion adsorbent according to Example 12-2 was produced in the same manner as in Example 9 except that.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.043 wt%.
Moreover, it was 0.13g when the weight of the obtained target metal ion adsorption agent was measured.

<Example 12-3>
In Example 9, instead of the ethanol aqueous solution of PMMA that was saturated and dissolved at room temperature, the PMMA ethanol aqueous solution that had been heated to 40 ° C. and before reaching room temperature was used, and that the weight average molecular weight was 120,000. Instead of using PMMA having a weight average molecular weight of 35,000, and changing the concentration of the FeCl ₃ aqueous solution from 80 mM to 123 mM, the Fe ion concentration in the organic phase (D2EHPA) becomes 0.69 wt%. A target metal ion adsorbent according to Example 12-3 was produced in the same manner as in Example 9 except that.
In addition, the density | concentration in the ethanol aqueous solution of PMMA was 0.41 wt%.
Moreover, it was 0.13g when the weight of the obtained target metal ion adsorption agent was measured.

(Example 13: Organophosphorus compound species)
<Example 13-1>
In Example 2-5, instead of adding 5 mL of D2EHPA to the YCl ₃ aqueous solution, 5 mL of Bis (2,4,4-trimethylpentyl) phosphonic acid (CYANEX272, manufactured by CYTEC CANADA INC.) Was added. The target metal ion adsorbent according to Example 13-1 was produced in the same manner as Example 2-5.
The weight of the obtained target metal ion adsorbent was measured and found to be 0.029 g.

<Example 13-2>
In Example 13-1, the target metal ion adsorbent according to Example 13-2 was obtained in the same manner as Example 13-1, except that 80 vol% 1-propanol aqueous solution was used instead of 80 vol% ethanol aqueous solution. Manufactured.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.022 g.

<Example 13-3>
In Example 13-1, a target metal ion adsorbent according to Example 13-3 was produced in the same manner as Example 13-1, except that a 90 vol% aqueous methanol solution was used instead of the 80 vol% aqueous ethanol solution. .
The weight of the obtained target metal ion adsorbent was measured and found to be 0.029 g.

<Example 13-4>
In Example 2-5, instead of adding 5 mL of D2EHPA to the YCl ₃ aqueous solution, 5 mL of 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A, manufactured by Daihachi Chemical Co., Ltd.) was added, and 80 vol. A target metal ion adsorbent according to Example 13-4 was produced in the same manner as in Example 2-5 except that an 80 vol% 1-propanol aqueous solution was used in place of the% ethanol aqueous solution.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.045 g.

(Example 14)
In Example 11-1, in place of PMMA, polyacrylonitrile (PAN) (manufactured by Aldrich, weight average molecular weight 150,000) was used, except that Example 14-1 was followed in the same manner as Example 11-1. The target metal ion adsorbent was produced.
In addition, the density | concentration in the ethanol aqueous solution of PAN was 0.10 wt%.
In addition, when the weight of the obtained target metal ion adsorbent was measured, it was 0.064 g.
Moreover, regarding Example 14, the particle size distribution of the obtained colloid is shown in FIG.

(Measurement results and evaluation)
<Physical properties>
An electron micrograph of the target metal ion adsorbent according to Example 1 is shown in FIG. The XRD spectrum is shown in FIG. It is confirmed that the target metal ion adsorbent obtained from these figures is solid and has crystallinity.
Moreover, the organic phase which moved the Fe ion in Example 1, and the FT-IR spectrum of the obtained target metal ion adsorption agent are shown to Fig.4 (a) and FIG.4 (b). FIG. 4 (a) shows carbon chain absorption, and no change is observed before and after precipitation. FIG. 4 (b) shows a vibration spectrum due to a phosphate group, which changes greatly before and after precipitation. From this, it is estimated that a phosphate group, an iron ion, and a counter anion interact and crystallize, and as a result, solidify and precipitate.

An electron micrograph of the target metal ion adsorbent according to Example 9 is shown in FIG. As shown in FIG. 5, the target metal ion adsorbent according to Example 9 is not significantly changed compared to the target metal ion adsorbent according to Example 1 (see FIG. 1).
Moreover, the ATRFT-IR spectrum of the target metal ion adsorbent according to Examples 9 and 10-1 is shown in FIG. As shown in FIG. 6, the target metal ion adsorbent according to Example 9 is not significantly changed as compared with the target metal ion adsorbent according to Example 1. In the spectrum of the target metal ion adsorbent according to Example 10-1, a peak is observed in the vicinity of 1,700 cm ⁻¹ . This is considered to be caused by PMMA, and it can be confirmed that the target metal ion adsorbent is precipitated simultaneously with PMMA in the ethanol solution.

  In addition, ATRFT-IR spectra of the target metal ion adsorbents according to Examples 10 to 12 and 14 are shown in FIGS. 7 to 26 (FIG. 7 shows Example 10-1 and FIG. 8 shows Example 10-2). 9 is Example 10-3, FIG. 10 is Example 10-4, FIG. 11 is Example 10-5, FIG. 12 is Example 10-6, FIG. 13 is Example 10-7, and FIG. Example 10-8, FIG. 15 is Example 10-9, FIG. 16 is Example 10-10, FIG. 17 is Example 10-11, FIG. 18 is Example 10-12, FIG. 19 is Example 10-13, 20 is Example 11-1, FIG. 21 is Example 11-2, FIG. 22 is Example 11-3, FIG. 23 is Example 12-1, FIG. 24 is Example 12-2, and FIG. 12-3 and Fig. 26 relate to Example 14. However, Example 11-4 is omitted in the figure).

<Target metal ion adsorption test>
Using the target metal ion adsorbents according to Examples 1 to 14 (except for the target metal ion adsorbents according to Examples 4-1, 4-4, 4-5, and 7-2), separation and recovery targets The target metal ion adsorption test was performed.
Specifically, about 0.02 g of the target metal ion adsorbent was shaken in 5 mL of an 80 mg · L ⁻¹ Dy (NO ₃ ) ₃ aqueous solution, and the amount of Dy ions (target metal ions) adsorbed was examined. The aqueous solution of Dy (NO ₃ ) ₃ was adjusted so that HNO ₃ was added to a pH = 2 state and NaNO ₃ was added to obtain an ionic strength I = 1. Further, the amount of Dy ions adsorbed was measured by measuring the Dy ion concentration in the aqueous solution by ICP emission spectroscopic analysis after shaking for 24 hours.
In addition, in the entire adsorption test using the target metal ion adsorbent according to Examples 1 to 14, Fe ions and D2EHPA were not detected in the solution after the adsorption test. However, in the adsorption test using the target metal ion adsorbent according to Example 12-1, Fe ions were not detected in the solution after the adsorption test, but the P ions considered to be derived from D2EHPA were 3.2 mg · This was confirmed by the concentration of L- ¹ . This is because when the precipitate precipitated in the gel-like mixed solution is filtered to obtain the target metal ion adsorbent according to Example 12-1, the filtration is insufficient and there are many liquid D2EHPA or D2EHPA-Fe complexes. This is thought to be due to adhesion.
The above results are shown in Table 1 below. However, the adsorption amount (mg) of Dy ions was expressed in terms of the amount per 1 g of metal ion adsorbent.

In addition, the symbol “*” in Table 1 indicates that no measurement is performed.

In the measurement of the amount of Dy ions adsorbed using the target metal ion adsorbent according to Example 1, measurement was performed in the same manner as described above except that NaNO ₃ was added and the ionic strength was set to I = 0.2. As a result, the amount of Dy ions adsorbed was 1.2 mg per gram of metal ion adsorbent with respect to the amount of Dy ions adsorbed (2.1 mg) obtained under the condition of ionic strength I = 1.
This confirms that the lower the ionic strength, the greater the amount of adsorption.

<Concentration of complex-forming metal ions and yield of target metal ion adsorbent>
Regarding the production of the target metal ion adsorbent according to Example 1, 7-1 to 7-5, the concentration (wt%) in the organic phase (D2EHPA) of the complex-forming metal ions (Fe ions) used for complex formation, FIG. 27 and FIG. 28 show the relationship with the yield calculated from the weight of the obtained target metal ion adsorbent (precipitate).
Here, FIG. 27 is a table showing the relationship between the Fe ion concentration and the yield, and FIG. 28 is a graph plotting the numerical values shown in FIG.
As understood from FIGS. 27 and 28, the yield tends to improve as the Fe ion concentration increases. However, as the Fe ion concentration increases to a certain level, the dependence of the yield on the Fe ion concentration decreases. This is presumably because the coordination of Fe ions to the organophosphorus compound becomes saturated.

<Concentration of complex-forming metal ions and adsorption amount of target metal ions>
Concerning the production of the target metal ion adsorbents according to Examples 1, 7-1, 7-3 to 7-5, the concentration (wt) of the complex-forming metal ions (Fe ions) used for complex formation in the organic phase (D2EHPA) %) And the Dy ion adsorption rate of the obtained target metal ion adsorbent (precipitate) is shown in FIG.
Here, FIG. 29 is a graph plotting the relationship between the Fe ion concentration and the Dy ion adsorption amount.
As understood from FIG. 29, the amount of adsorption of Dy ions tends to improve as the Fe ion concentration increases. However, as the Fe ion concentration increases to a certain level, the dependence of the yield on the Fe ion concentration decreases.

<Ethanol concentration and yield of target metal ion adsorbent>
30 and FIG. 30 show the relationship between the ethanol concentration and the weight of the obtained target metal ion adsorbent (precipitate) regarding the production of the target metal ion adsorbent according to Examples 4-1 to 4-5 and 7-2. 31.
Here, FIG. 30 is a table showing the relationship between the ethanol concentration in the aqueous ethanol solution and the yield, and FIG. 31 is a graph plotting the numerical values shown in FIG.
As understood from FIG. 30 and FIG. 31, the yield of the target metal ion adsorbent (precipitate) obtained varies depending on the ethanol concentration in the aqueous solution, and the mixing that can produce the target metal ion adsorbent with high efficiency The concentration range of the solution is remarkably confirmed.

<Mixing ratio of metal complex / mixed solution and yield of target metal ion adsorbent>
Regarding the production of the target metal ion adsorbent according to Examples 8-1 to 8-5, the mixing ratio of the metal complex / mixed solution (water and ethanol) and the yield of the obtained target metal ion adsorbent (precipitate) The relationship is shown in FIG. 32 and FIG.
Here, FIG. 32 is a table showing the relationship between the mixing ratio (volume ratio) of the metal complex / mixed solution (water and ethanol) and the yield of the obtained target metal ion adsorbent (precipitate). FIG. 33 is a graph in which the numerical values shown in FIG. 32 are plotted.
As can be understood from FIG. 33, the yield is substantially the same when the mixing ratio (volume ratio) of the metal complex / mixed solution is in the range of 0.09 to 0.23. , The tendency for the yield to be low is confirmed. Therefore, in order to efficiently produce the target metal ion adsorbent, it is preferable that the mixing ratio (volume ratio) of the metal complex / mixed solution is in the range of 0.09 to 0.23.

<Multi-ion adsorption / desorption test>
In Example 1, the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 53 mM, and the Fe ion concentration in the organic phase (D2EHPA) was 0.38 wt%. A target metal ion adsorbent (A) for an ion adsorption / desorption test was produced.
Of these, the 100 mg, Ce ions 15.8 mg ^{· L} -1, Sm ions 16.7 mg ^{· L} -1, Nd ion 16.7 mg ^{· L} -1, and an aqueous solution 15mL containing Dy ions 20.8 mg · ^{L -1} Mix and shake for 24 hours. However, the aqueous solution was HNO ₃ , pH = 4.0, and NaNO ₃ was used to make the ionic strength I = 1.
The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The adsorption rate of each ion was Ce ion: 6.3%, Sm ion: 9.0%, Nd ion: 7.8%, Dy ion: 25%.

The target metal ion adsorbent (A) subjected to the previous measurement was filtered, and then shaken in an aqueous solution prepared with HNO ₃ to pH = 2.7 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. Under these conditions, no ions were desorbed.

Next, the target metal ion adsorbent (A) was filtered again and then shaken in an aqueous solution prepared with HNO ₃ to pH = 2.0 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 6.5%, Sm ion: 6.9%, Nd ion: 4.6%, Dy ion: 3.9%.

Next, the target metal ion adsorbent (A) was filtered again and then shaken in an aqueous solution prepared with HNO ₃ to pH = 0.9 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 14.8%, Sm ion: 28%, Nd ion: 17%, Dy ion: 52%.

In Example 9, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 53 mM, and the Fe ion concentration in the organic phase (D2EHPA) was 0.38 wt%. The target metal ion adsorbent (B) for the adsorption / desorption test was produced.
Of these, the 100 mg, Ce ions 15.8 mg ^{· L} -1, Sm ions 16.7 mg ^{· L} -1, Nd ion 16.7 mg ^{· L} -1, and an aqueous solution 15mL containing Dy ions 20.8 mg · ^{L -1} Mix and shake for 24 hours. However, the aqueous solution was HNO ₃ , pH = 4.0, and NaNO ₃ was used to make the ionic strength I = 1.
The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The adsorption rate of each ion was Ce ion: 7.6%, Sm ion: 11%, Nd ion: 9.0%, Dy ion: 32%.

The target metal ion adsorbent (B) used in the previous measurement was filtered, and then shaken in an aqueous solution prepared with HNO ₃ to pH = 2.7 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. Under these conditions, no ions were desorbed.

Next, the target metal ion adsorbent (B) was filtered again and then shaken for 24 hours in an aqueous solution adjusted to pH = 2.0 with HNO ₃ . The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 6.6%, Sm ion: 6.7%, Nd ion: 4.8%, Dy ion: 5.3%.

Next, the target metal ion adsorbent (B) was filtered again and then shaken in an aqueous solution prepared with HNO ₃ to pH = 0.9 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 15%, Sm ion: 26%, Nd ion: 16%, Dy ion: 52%.

In Example 10-7, the FeCl ₃ aqueous solution concentration was changed from 80 mM to 53 mM, and the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.38 wt%, as in Example 10-7. Thus, the target metal ion adsorbent (C) was produced.
Of these, the 100 mg, Ce ions 15.8 mg ^{· L} -1, Sm ions 16.7 mg ^{· L} -1, Nd ion 16.7 mg ^{· L} -1, and an aqueous solution 15mL containing Dy ions 20.8 mg · ^{L -1} Mix and shake for 24 hours. However, the aqueous solution was HNO ₃ , pH = 4.0, and NaNO ₃ was used to make the ionic strength I = 1.
The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The adsorption rate of each ion was Ce ion: 98%, Sm ion: 100%, Nd ion: 100%, Dy ion: 100%.

The target metal ion adsorbent (C) subjected to the previous measurement was filtered, and then shaken in an aqueous solution prepared with HNO ₃ to pH = 2.7 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of Ce ions was 0.23%. Sm ions, Nd ions, and Dy ions were not desorbed.

Next, the target metal ion adsorbent (C) was filtered again and then shaken in an aqueous solution prepared with HNO ₃ to pH = 2.0 for 24 hours. The ionic strength is not adjusted. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 72%, Sm ion: 62%, Nd ion: 77%, Dy ion: 14%.

Next, the target metal ion adsorbent (C) was filtered again and then shaken in an aqueous solution prepared with HNO ₃ to pH = 0.9 for 24 hours. The ion concentration in the solution obtained by filtration was measured by ICP emission spectroscopic analysis. The desorption rate of each ion was Ce ion: 11%, Sm ion: 30%, Nd ion: 15%, Dy ion: 54%.

  As can be understood from the above adsorption / desorption test of multiple ions, the target metal ion adsorbents (A) to (C) adsorb these from an aqueous solution containing a plurality of target metal ions to be separated and recovered. In addition, from the state where a plurality of ions are adsorbed, various ions can be selectively desorbed by shaking in an aqueous solution in which pH conditions are appropriately set.

<Repeated adsorption / desorption test>
In Example 1, the concentration of FeCl ₃ aqueous solution was changed from 80 mM to 53 mM, and the concentration of Fe ions in the organic phase (D2EHPA) was 0.38 wt%. A target metal ion adsorbent (a) for desorption test was produced.
Of these, 200 mg was packed in a column, and 15 mL of 80 mg · L ⁻¹ Dy (NO ₃ ) ₃ aqueous solution with pH = 2.0 with HNO ₃ and ionic strength I = 1 with NaNO ₃ was flowed (adsorption), then Then, 20 mL of an aqueous solution adjusted to pH = 0.9 with HNO ₃ was allowed to flow (desorption). This was repeated three times, the Dy ion concentration in each solution was measured, and the Dy ion adsorption amount and desorption amount were measured.
The results are shown in Table 2 below.

In Example 9, the concentration of the FeCl ₃ aqueous solution was changed from 80 mM to 53 mM, and the Fe ion concentration in the organic phase (D2EHPA) was changed to 0.38 wt%. A target metal ion adsorbent (b) for desorption test was produced.
Of these, 200 mg was packed in a column, and 15 mL of 80 mg · L ⁻¹ Dy (NO ₃ ) ₃ aqueous solution with pH = 2.0 with HNO ₃ and ionic strength I = 1 with NaNO ₃ was flowed (adsorption), then Then, 20 mL of an aqueous solution adjusted to pH = 0.9 with HNO ₃ was allowed to flow (desorption). This was repeated three times, the Dy ion concentration in each solution was measured, and the Dy ion adsorption amount and desorption amount were measured.
The results are shown in Table 3 below.

Example 10-7 was the same as Example 10-7 except that the FeCl ₃ aqueous solution concentration was changed from 80 mM to 53 mM so that the Fe ion concentration in the organic phase (D2EHPA) was 0.38 wt%. Thus, a target metal ion adsorbent (c) for repeated adsorption / desorption tests was produced. Of these, 200 mg was packed in a column, and 15 mL of 80 mg · L ⁻¹ Dy (NO ₃ ) ₃ aqueous solution with pH = 2.0 with HNO ₃ and ionic strength I = 1 with NaNO ₃ was flowed, and then HNO ₃ Then, 20 mL of an aqueous solution having a pH of 0.9 was flowed. This was repeated three times, the Dy ion concentration in each solution was measured, and the Dy ion adsorption amount and desorption amount were measured.
The results are shown in Table 4 below.

  As understood from the above repeated adsorption / desorption tests, the target metal ion adsorbents (a) to (c) can repeatedly adsorb and desorb target metal ions to be separated and recovered.

  The objective metal ion adsorbent of the present invention and the method for producing the same can separate the objective metal ions contained in the solution with low cost and high versatility, and can be produced simply and efficiently. In addition, since it can be used repeatedly, from a small amount of solution processing performed in experiments to a large amount of solution processing performed industrially, and further including rare earth elements that have been conventionally difficult, a wide range of target metals It can be used in the field of ion separation and recovery.

Claims (17)

A metal complex containing solid organic phosphorus compounds seen including,
The organophosphorus compound is selected from any of Bis (2-ethylhexyl) phosphoric acid, 2-Ethylhexylphosphonic acid mono-2-ethylhexylester, and Bis (2,4,4-trimethylpentyl) phosphonic acid. The purpose metal ion adsorbent. The target metal ion adsorbent according to claim 1, wherein the metal forming the metal complex is any one of Fe, Dy, La, In, and Y. Furthermore, the target metal ion adsorption agent in any one of Claim 1 to 2 containing the hydrophilic improvement polymer which improves the hydrophilic property of a metal complex. The target metal ion adsorbent according to claim 3, wherein the hydrophilicity-improving polymer is any one of polymethyl methacrylate and polyacrylonitrile, and a copolymer containing structural units of these monomers. The target metal ion adsorbent according to claim 4, wherein the hydrophilicity-improving polymer is polymethyl methacrylate. The target metal ion adsorbent according to claim 5, wherein the polymethyl methacrylate has a weight average molecular weight of 1,000 to 150,000,000. The metal ion adsorbent according to any one of claims 3 to 6, wherein the content ratio of the metal complex and the hydrophilic polymer and the metal complex / hydrophilic polymer are 10 to 100 by mass ratio. A metal complex containing a liquid organophosphorus compound is contained in a mixed solution of two or more liquids to generate a precipitate containing the metal complex, and the metal complex is contained from the precipitate. A metal ion adsorbent acquisition step of acquiring a metal ion adsorbent,
  The organophosphorus compound is selected from any of Bis (2-ethylhexyl) phosphoric acid, 2-Ethylhexylphosphonic acid mono-2-ethylhexylester, and Bis (2,4,4-trimethylpentyl) phosphonic acid. A method for producing a metal ion adsorbent. The method for producing a target metal ion adsorbent according to claim 8, wherein the metal forming the metal complex is any one of Fe, Dy, La, In and Y. The precipitate generation step includes at least a metal complex and a hydrophilicity-improving polymer that improves the hydrophilicity of the metal complex in a mixed solution, and the composite aggregate includes the metal complex and the hydrophilicity-improving polymer. The method for producing a target metal ion adsorbent according to any one of claims 8 to 9, which is a step of generating a precipitate. The precipitate generating step is a step of heating the mixed solution in which the hydrophilicity improving polymer is dissolved to obtain a colloidal solution in which colloidal particles of the hydrophilicity improving polymer are dispersed, and then adding at least a metal complex to the colloidal solution. The manufacturing method of the target metal ion adsorption agent of Claim 10. The method for producing a target metal ion adsorbent according to any one of claims 10 to 11, wherein the hydrophilicity-improving polymer is any one of polymethyl methacrylate, polyacrylonitrile, and a copolymer containing constituent units of these monomers. The method for producing a target metal ion adsorbent according to claim 12, wherein the hydrophilicity-improving polymer is polymethyl methacrylate. The method for producing a target metal ion adsorbent according to claim 13, wherein the polymethyl methacrylate has a weight average molecular weight of 1,000 to 150,000,000. The method for producing a target metal ion adsorbent according to any one of claims 8 to 14, wherein the mixed solution is a mixed solution of an organic solvent in which a metal complex is soluble and water. The method for producing a target metal ion adsorbent according to claim 15, wherein the organic solvent is one of alcohol and ketone. The method for producing a target metal ion adsorbent according to claim 16, wherein the mixed solvent is an aqueous ethanol solution having a concentration of 65 vol% or more and less than 100 vol%.