JP5376627B2 - Photoresponsive copper ion adsorbing material and copper ion recovery method - Google Patents

Abstract

A photoresponsive copper ion adsorbent material containing a copolymer which is obtained by copolymerization of a monomer component containing both a photoresponsive compound exhibiting reversible metal ion adsorption-desorption transition in dependence of light in a metal ion solution and a quaternized amine compound, wherein the copolymer can selectively adsorb copper(II) ions in a dark place from a metal ion solution containing chloride ions, sodium ions, and copper(II) ions. Thus, only copper(II) ions can be adsorbed selectively among metal ions, and recovered through desorption.

Description

  The present invention relates to a photoresponsive copper ion adsorbing material and a copper ion recovery method using the same.

In recent years, a method of efficiently recovering metal ions from industrial waste liquid and industrial waste discharged from factories and the like is desired for reasons of environmental pollution prevention, industrial waste reduction, and resource reuse.
As a method for purifying waste liquid containing metal ions, a neutralization coagulation precipitation method, a sodium sulfide method, a heavy metal scavenger method, a ferrite method and the like have been put into practical use. After the waste liquid is treated by these methods, a step of recovering the metal and a step of reusing it are provided.
For example, the heavy metal scavenger method uses a scavenger (for example, a cyanide compound) that forms a complex compound with heavy metal ions. In order to recover the metal ions adsorbed to the collection agent after the collection treatment, the collection agent is generally soluble in the solution, so that the collection agent is separated from the metal ions through a chemical reaction treatment such as an oxidation treatment. Thereafter, the metal is isolated as a cation in a solution and purified and recovered.
In carrying out the chemical reaction process in the heavy metal recovery step after heavy metal collection by the collection agent as described above, not only specialized knowledge and technology are required, but also complicated operations and long treatment time due to it. It took a lot of processing costs.

Accordingly, it includes a copolymer having a segment of a photochromic compound and a fluoroalcohol that reversibly discolors depending on whether or not the compound is irradiated with light. Adsorption and desorption of metal ions in a solution in response to light irradiation A metal ion adsorbing material having both functions has been proposed (see, for example, Patent Document 1).
JP 2003-053185 A

However, when the above adsorbing material is used in a solution containing a plurality of types of metal ions, it is adsorbed without depending on the type of metal ions, so that it is difficult to recover only specific metal ions.
An object of the present invention is to provide an adsorbent material that can selectively and efficiently recover copper (II) ions among metal ions.

That is, the present invention relates to the following (1) to (16).
(1) a photoresponsive compound that reversibly transitions between adsorption and desorption of metal ions in a metal ion solution depending on the presence or absence of light irradiation;
A photoresponsive copper ion adsorbing material comprising a copolymer obtained by copolymerizing a monomer component containing a quaternized amine compound.

(2) The photoresponse according to (1), wherein the copolymer selectively adsorbs copper (II) ions in a dark place from a metal ion solution containing chlorine ions, sodium ions and copper (II) ions. Copper ion adsorption material.

（式（I）および（II）中、Ｘは水素原子が一個結合した炭素原子、または窒素原子であり、Ｙは酸素原子または硫黄原子である。Ｒ_１、Ｒ_２は独立に水素原子またはアルキル基であり、Ｒ_３はアルキル基である。
（４） 前記四級化アミン化合物は、下式（IV）で示される基および重合可能なエチレン性不飽和結合を有する前記（１）〜（３）のいずれか記載の光応答性銅イオン吸着材料。

（５） 前記四級化アミン化合物は、下式（V）で示される基および重合可能なエチレン性不飽和結合を有する前記（１）〜（３）のいずれか記載の光応答性銅イオン吸着材料。

(3) The light according to (1) or (2), wherein the photoresponsive compound is a compound having a group represented by the following formula (I) or (II) and a polymerizable ethylenically unsaturated bond: Responsive copper ion adsorption material.

(In the formulas (I) and (II), X is a carbon atom to which one hydrogen atom is bonded, or a nitrogen atom, Y is an oxygen atom or a sulfur atom. R ₁ and R ₂ are independently a hydrogen atom or alkyl. And R ₃ is an alkyl group.
(4) The photoresponsive copper ion adsorption according to any one of (1) to (3), wherein the quaternized amine compound has a group represented by the following formula (IV) and a polymerizable ethylenically unsaturated bond: material.

(5) The photoresponsive copper ion adsorption according to any one of (1) to (3), wherein the quaternized amine compound has a group represented by the following formula (V) and a polymerizable ethylenically unsaturated bond: material.

(6) The copolymer is 1 ′, 3 ′, 3′-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2′-indole) or 1 ′, 3 ′, 3 ′. -Trimethyl-6- (methacryloyloxy) spiro (2H-1-benzopyran-2,2'-indole);
(1) to (1) obtained by copolymerizing a monomer component containing N, N, N-trimethyl-N-acryloyloxyethylammonium chloride or N, N, N-trimethyl-N-methacryloyloxyethylammonium chloride. The photoresponsive copper ion adsorbing material according to any one of 4).
(7) The copolymer is 1 ′, 3 ′, 3′-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2′-indole) or 1 ′, 3 ′, 3 ′. -Trimethyl-6- (methacryloyloxy) spiro (2H-1-benzopyran-2,2'-indole);
[2- (acryloyloxy) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide or
Any one of (1) to (3) and (5) above, wherein a monomer component containing [2- (methacryloyloxy) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide is copolymerized. The photoresponsive copper ion adsorbing material described.

(8) The photoresponsive copper ion adsorbing material according to any one of (1) to (7), wherein the copolymer is supported on a substrate.
(9) The photoresponsive copper ion adsorption according to (8), wherein the substrate is any one of glass, metal oxide, silicon oxide, silica gel, diatomaceous earth, a styrene polymer, an acrylic acid polymer, and a methacrylic acid polymer. material.
(10) The photoresponsive copper ion adsorbing material according to any one of (1) to (9), further including a crosslinking agent or a coupling agent in the monomer component.
(11) The photoresponsive copper ion adsorbing material according to any one of (8) to (10), wherein a copolymer is supported on fibers, fine particles, or thin tubes.

(12) Using the photoresponsive copper ion adsorbing material according to any one of (1) to (11) above, from a metal ion solution containing copper (II) ions, chlorine ions and sodium ions, copper (II) ions Is selectively recovered in a recovery solvent.
(13) a step of adsorbing the copolymer of the photoresponsive copper ion adsorbing material and copper (II) ions by complex formation in the dark in the presence of chlorine ions and sodium ions;
The method for recovering copper ions according to (12), comprising a step of desorbing copper (II) ions from the copolymer in a recovery solvent.
(14) The copper ion recovery method according to the above (12) or (13), wherein chlorine ions and sodium ions in the metal ion solution are 10 wt% or less in terms of sodium chloride concentration.
(15) The copper ion recovery method according to the above (13), wherein the recovery solvent is water not containing sodium chloride in the step of desorbing copper (II) ions from the copolymer.
(16) The copper ion according to (13), wherein, in the step of desorbing copper (II) ions from the copolymer, the recovery solvent is an aqueous solution of sodium chloride, and the copper ions are desorbed by irradiation with visible light. Collection method.

According to the present invention, only copper ions among metal ions can be selectively adsorbed, desorbed and recovered. Furthermore, since the salt required for the adsorption of copper ions does not have a particularly adverse effect on the living body, the solution at the time of collecting copper ions and the waste liquid after the recovery of copper ions are safe to handle. In addition, workability is good because the temperature range of the solution that can be adsorbed / desorbed is wide.
Furthermore, the copper ion adsorbing material of the present invention can be used not only for the recovery of copper ions, but also as a copper (II) ion sensor based on the presence of color change or fluorescence.

式（I）および（II）中、Ｘは水素原子が一個結合した炭素原子、または窒素原子であり、Ｙは酸素原子または硫黄原子である。Ｒ_１、Ｒ_２は独立に水素原子またはアルキル基であり、Ｒ_３はアルキル基である。また、アルキル基は、具体的にはメチル基、エチル基、ドデシル基等が例示され、メチル基が好ましい。
式（I）および（II）中、ベンゼン環に結合している水素原子は置換されていてもよい。この場合の置換基は例えばメチル基、メトキシ基、アミノ基、ニトロ基、ハロゲン基、シアノ基、等が例示され、金属イオンとの錯形成効率の点からは、置換しないかまたはメトキシ基、メチル基、アミノ基等の電子供与性の置換基が好ましい。置換する場合の置換基数は、１つのベンゼン環に１または２が好ましい。また、この置換基は、隣接する二つの炭素原子に環状に結合することにより、前記ベンゼン環と共にナフタレン環を形成してもよい。
なお、Ｘが炭素原子でＹが酸素原子の場合がスピロピラン、Ｘが窒素原子でＹが酸素原子の場合はスピロオキサジンである。以下、共重合体がスピロピランから得られる場合について具体的に説明するが、スピロオキサジンを用いても同様の光応答性を示す。 Embodiments of the present invention will be described below.
The monomer component of the copolymer contained in the photoresponsive copper ion adsorbing material of the present invention,
A photoresponsive compound that reversibly adsorbs and desorbs metal ions in liquid in response to the presence or absence of light irradiation;
A quaternized amine compound.
In the present invention, a compound having a group represented by the following formula (I) or (II) and a polymerizable ethylenically unsaturated bond is used as the photoresponsive compound. The two types of groups are derived from a spiropyran compound or a spirooxazine compound that can take a merocyanine structure.

In the formulas (I) and (II), X is a carbon atom to which one hydrogen atom is bonded, or a nitrogen atom, and Y is an oxygen atom or a sulfur atom. R ₁ and R ₂ are independently a hydrogen atom or an alkyl group, and R ₃ is an alkyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, and a dodecyl group, and a methyl group is preferable.
In formulas (I) and (II), the hydrogen atom bonded to the benzene ring may be substituted. Examples of the substituent in this case include a methyl group, a methoxy group, an amino group, a nitro group, a halogen group, and a cyano group. From the viewpoint of complex formation efficiency with a metal ion, the substituent is not substituted or a methoxy group, methyl An electron donating substituent such as a group or an amino group is preferred. In the case of substitution, the number of substituents is preferably 1 or 2 for one benzene ring. Moreover, this substituent may form a naphthalene ring with the said benzene ring by couple | bonding cyclically with two adjacent carbon atoms.
In addition, when X is a carbon atom and Y is an oxygen atom, it is spiropyran, and when X is a nitrogen atom and Y is an oxygen atom, it is spirooxazine. Hereinafter, although the case where a copolymer is obtained from spiropyran is demonstrated concretely, even if it uses spirooxazine, the same photoresponsiveness is shown.

The mechanism of photochromism that isomerizes between two states with different absorption spectra without changing the molecular weight by light irradiation is considered as the following formula (III). Spiropyran is reversibly isomerized into a spiropyran structure and a merocyanine structure by irradiation with visible light (> 420 nm). The spiropyran structure under visible light irradiation is closed in water and is electrically neutral. When the visible light irradiation is stopped and the spiropyran structure is placed in the dark, it is transferred to the merocyanine structure. It is open and has zwitterions in the molecule. The atom of Y has a high electron density and can complex with a cation at this site. Moreover, it exhibits a different color from the spiropyran structure. This complex formation disappears when the merocyanine structure returns to the spiropyran structure.
In order to stop the visible light irradiation and put it in a dark place, ultraviolet light irradiation may be used instead. In this case, when the visible light is irradiated next time, the ultraviolet light irradiation is stopped simultaneously.
The behavior of the above spiropyran is the same even when an ester bond is formed at the R ₇ or R ₃ group and further copolymerized.

In formula (III), R ₁ and R ₂ are independently a hydrogen atom or an alkyl group,
One of R ₃ and R ₇ is hydrogen or a polymerizable monovalent substituent, and the other is an alkyl group, a hydroxyl group, a carboxyl group, an amino group, an aldehyde group, or an amide group. Here, since it uses for a monomer component, it is preferable that the said substituent has a polymerizable ethylenically unsaturated bond, for example, a (meth) acryloyloxy group and a vinyl group are mentioned.

  A specific photoresponsive compound used as a monomer component for the copolymer is preferably a spiropyran compound. In particular, 1 ′, 3 ′, 3′-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2′-indole) is preferable, and hereinafter also referred to as SPAA or spiropyran acrylate. In addition, a compound in which the acryloyloxy group of SPAA is a methacryloyloxy group is also preferable, and hereinafter referred to as SPMA or spiropyran methacrylate.

第一の実施態様として、式（IV）の基を含むＮ，Ｎ，Ｎ−トリメチル−Ｎ−アクリロイルオキシエチルアンモニウムクロリドが挙げられる。以下、ＴＭＡＥＭＡＣｌともいう。
第二の実施態様として、式（V）の基を含む[２−（メタクリロイルオキシ）エチル]−ジメチル−（３−スルホプロピル）−アンモニウムヒドロキシドが挙げられる。以下、ＭＤＳＡともいう。
上記の、アクリロイル基とメタクリロイル基とはどちらでもよく、重合可能なエチレン性不飽和結合を有している。 The quaternized amine as the raw material for the other monomer component may be a halogen salt type, a betaine type or a sulfobetaine type.
There is no restriction | limiting in particular in the hydrocarbon group couple | bonded with the nitrogen atom of a quaternized amine compound. The quaternized amine compound preferably has, for example, a group represented by the following formula (IV) or formula (V) and a polymerizable ethylenically unsaturated bond.

A first embodiment includes N, N, N-trimethyl-N-acryloyloxyethylammonium chloride containing a group of formula (IV). Hereinafter also referred to as TMAEMACl.
A second embodiment includes [2- (methacryloyloxy) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide containing a group of formula (V). Hereinafter, it is also referred to as MDSA.
The acryloyl group and methacryloyl group described above may be either one and have a polymerizable ethylenically unsaturated bond.

Polymerization of the photoresponsive compound and the quaternized amine compound may be block copolymerization or random copolymerization, and is not particularly limited.
The polymerization ratio is appropriately selected according to the hydrophilicity. If there are many photoresponsive compounds, the number of complex formation sites with copper ions in the photoresponsive compound simply increases, so that the copper ion adsorption ability increases. Moreover, if there are many quaternized amine compounds, there exists a tendency for copper ion selectivity to improve.

  For example, in the case of random copolymerization, the molar fraction (molar ratio) of the photoresponsive compound to the quaternized amine compound is not particularly limited, but if n and (1-n), respectively, 0 <n ≦ 0. 5 is preferred. In the case of other block or graft copolymerization, the molar fraction is not particularly limited.

Ｃｕ（II）イオン、およびＺｎ（II）イオン、Ｎｉ（II）イオン等の任意の二価の金属イオンの水溶液に、さらに塩化ナトリウム（食塩）を溶解させた水溶液を用意する。これにＰ（ＳＰＡＡ−ＴＭＡＥＭＡＣｌ）の粉末を溶解させ、暗所下で保持すると、各種金属イオンのうちＣｕ（II）イオンのみが選択的にＳＰＡＡセグメントの開環部位と錯形成することができる。Ｃｕ（II）イオンを含まない金属イオン溶液の場合は、塩化ナトリウムを含んでいても、錯形成は殆ど生じない。
なお、塩化ナトリウムの代わりに同じハロゲン化ナトリウムである、臭素イオン及びナトリウムイオン、また、ヨウ素イオン及びナトリウムイオンの存在下でも、同様に暗所下でＣｕ（II）イオンを選択的に吸着できるが、吸着率が低いので、塩化ナトリウムが好ましい。 Hereinafter, the case where the photoresponsive compound is spiropyran acrylate and the quaternized amine compound is TMAEMACl will be described to explain the copper ion adsorbing material of the present invention. The following Cu, Zn, Ni, Co, Cd, and Pb ions refer to divalent ions unless otherwise specified.
A copolymer of SPAA and TMAEMACl is represented as P (SPAA-TMAEMACl). This structure and behavior are shown in the following formula (VI).

An aqueous solution in which sodium chloride (sodium chloride) is further dissolved in an aqueous solution of an arbitrary divalent metal ion such as Cu (II) ion, Zn (II) ion, Ni (II) ion or the like is prepared. When P (SPAA-TMAEMACl) powder is dissolved in this and kept in the dark, only Cu (II) ions among various metal ions can selectively form a complex with the ring-opening site of the SPAA segment. In the case of a metal ion solution that does not contain Cu (II) ions, complex formation hardly occurs even if sodium chloride is included.
In addition, Cu (II) ions can be selectively adsorbed in the dark similarly in the presence of bromine ions and sodium ions, and iodine ions and sodium ions, which are the same sodium halides instead of sodium chloride. Sodium chloride is preferred because of its low adsorption rate.

  The UV-visible absorption spectrum of the Cu, Zn, Ni, Co, and Cd metal (II) ion solutions not containing sodium chloride and the metal-free blank solution in FIG. ) Using the ultraviolet-visible absorption spectrum of each solution containing sodium chloride. The spectrum when these solutions are kept in a dark place is a solid line, and when visible light is irradiated, the absorption of the spectrum is attenuated as shown by the dotted line. When light irradiation is stopped and kept in a dark place, the spectrum returns to the solid line again.

In FIG. 1A, the spectrum of each solution in the dark shows an absorption band near 530 nm, which is different from that under light irradiation (dotted line). Here, even if the blank SPAA segment is ring-opened, there is no metal ion, so this absorption band near 530 nm is based on a free ring-opened body (merocyanine structure). Since the solution containing each metal chloride shows a similar absorption band, almost no metal ions are complexed.
When sodium chloride is included in FIG. 1B, the metal ions other than Cu have an absorption band spectrum almost similar to that in FIG. That is, Zn, Ni, Co, and Cd ions cannot be complexed even in the presence of sodium chloride. An absorption band derived from a complex with the SPAA segment is obtained in the vicinity of 410 to 420 nm only in the dark in the presence of Cu (II) ions.

The preferred chloride ion (chloride ion, Cl ⁻ ) and sodium ion (Na ⁺ ) concentration in the metal ion solution depends on the molar ratio of the SPAA segment to the Cu (II) ion in terms of sodium chloride, but the SPAA : Cu (II) = 1: 10, 10 wt% or less is sufficient. Even if the concentration is higher than 10 wt%, the copper ion adsorption ability is not improved. If it is 5 wt%, the maximum amount (10 wt%) of about 3/4 of copper ions can be adsorbed.
The preferred molar ratio between the SPAA segment in the copolymer and the Cu (II) ion in the solution depends on the salt concentration, but in the case of saturated saline, the SPAA segment: Cu (II) = 1: 1 or more. preferable.

  The sodium chloride concentration when the adsorbing material of the present invention is used as a Cu (II) ion sensor due to a change in the color of the solution is not particularly limited as long as a complex formation absorption band can be detected, but about 1 wt% or more. Is preferred. Also, the molar ratio of SPAA segment: Cu (II) is not particularly limited as long as a complex formation absorption band can be detected, but it is preferably 1: 0.2 or more.

The copolymer preferably contains a crosslinking agent such as N, N′-methylenebisacrylamide in order to insolubilize in water and impart a shape. As the crosslinking agent, generally used crosslinking agents can be used. A content of about several mol% is sufficient in the copolymer component. As a result, the copolymer becomes an insoluble gel, and can be selectively adsorbed to copper ions, for example, if it is put into a metal ion solution tank or filled in a column into which a metal ion solution flows. .
Further, the copolymer may be polymerized by containing monomer components other than those listed above as long as they do not interfere with the adsorption / desorption action of the adsorbing material. Examples thereof include a monomer component that imparts hydrophilicity, a photosensitizer, and a flexible agent.
The copolymer can be obtained by a conventionally known polymerization reaction by appropriately using a polymerization initiator, a solvent, a reaction terminator and the like for the above monomer components.
When MDSA is used in place of TMAEMACl, it reacts with copper ions in the same manner, but the MDSA copolymer tends to impart a shape more easily than the TMAEMACl copolymer.

The above-mentioned copolymer or gel thereof may be used as the photoresponsive copper ion adsorbing material of the present invention. In addition, the photoresponsive copper of the present invention may be obtained by supporting a copolymer on a substrate. It is good also as an ion adsorption material. The substrate is not particularly limited as long as it can support the photoresponsive copper ion adsorbing material, but the photoresponsive copper ion adsorbing material can reversibly adsorb / desorb copper ions and is repeatedly used. In view of this, it is important that the substrate serving as the carrier is a material having high mechanical stability and chemical stability. Moreover, it is preferable that it is porous.
For example, for inorganic materials, alumina, silica, silica / alumina, magnesia, zirconia, zinc oxide and other metal oxides, glass, crystalline aluminosilicate, silicon oxide, silica gel, diatomaceous earth, talc, silicon carbide and other silicon compounds, clay minerals (Including intercalation compounds), carbon such as activated carbon, and mixtures thereof. Examples of organic materials include synthetic polymers such as transparent polymers obtained by polymerizing styrene, acrylic acid, methacrylic acid, and the like. Organic materials are sufficient in strength, and inorganic materials are preferred in terms of chemical corrosion resistance.
In order to determine the adsorption / desorption of copper ions by a change in the color of the solution, and since the desorption of adsorbed copper ions is performed by irradiation with visible light, it is preferable to use a transparent material, especially glass. preferable.

Furthermore, from the viewpoint of increasing the loading efficiency of the photoresponsive copper ion adsorbing material, it is better that the surface area per unit amount of the substrate is large, and from the viewpoint of improving the light transmission performance, a substrate having a high porosity is used. preferable. From these, for example, if a nonwoven fabric is made of fibers such as glass fibers, the substrate can be formed into an arbitrary shape such as a sheet shape. In addition to the fiber, a substrate formed into a fine particle such as a bead or a hollow thin tube is also preferable.
In order to avoid damage due to the contact pressure with the metal ion solution or to increase the surface area of the adsorbent material in contact with the solution, it is necessary to leave the pores and pores of the porous material to some extent to carry the adsorbent material. preferable.

In order to carry a copolymer on these substrates, when the copolymerization is carried out, the substrate is added to the polymerization system, and a method of carrying the copolymer on the substrate simultaneously with the polymerization of the monomer, a solution of the copolymer is prepared, Examples include an impregnation method in which the substrate is immersed in a solution, a method in which the solvent is evaporated to dryness after impregnation, and a method in which the solution is applied to the substrate. In particular, in order to carry on the inner wall of the tube of the tubular substrate, inflow or immersion of the solution is preferable.
Of the above supporting methods, the method of supporting the substrate simultaneously with the polymerization of the monomer is preferable in that the process can be simplified. Also, the impregnation method is preferable because it is simple and can be efficiently supported.
Further, the supporting method of adding the monomer component for forming the silane coupling in the copolymer is preferable because the silane coupling portion is firmly supported by a chemical bond with a substrate such as glass. . In this case, the monomer component for silane coupling may be added at the time of polymerization, or after it is supported on the substrate, the substrate is added to the polymerization system at the time of polymerization and is supported on the substrate simultaneously with the polymerization. Also good.

As described above, the copolymer can be formed into a gel, a supported sheet, a bead, a tube or any other shape that can be easily brought into contact with a metal ion solution in combination with a crosslinking agent, a coupling agent, and a substrate. it can. For example, gel or beads can be filled in a column or filter, and a metal ion solution can be injected and permeated.
Furthermore, it is good also considering sodium chloride for copper ion adsorption, or its aqueous solution as a set with a copolymer or a supported copolymer.

The method for recovering copper ions in the present invention is as follows:
Using the photoresponsive copper ion adsorbing material, copper (II) ions are selectively recovered from a metal ion solution containing copper (II) ions, chlorine ions and sodium ions into a recovery solvent. And
For example, a step of adsorbing the copolymer of the photoresponsive copper ion adsorbing material and copper ions by complex formation in the dark in the presence of chlorine ions and sodium ions,
And a step of desorbing copper ions from the copolymer in a recovery solvent.
Specifically, first, the photoresponsive copper ion adsorbing material is brought into contact with a metal ion solution containing copper ions, chlorine ions and sodium ions.
This is held in the dark, and only copper ions are adsorbed on the corresponding segment of the copolymer by complex formation.
Next, with the copper ion adsorbed on the copolymer, in the case of a batch type, the photoresponsive copper ion adsorbing material is taken out from the metal ion solution and put into a recovery solvent. If it is a continuous type, it is made to contact in the collection | recovery solvent after completion | finish of contact with a metal ion solution.

If the recovery solvent does not contain sodium chloride such as water, copper ions cannot be complexed regardless of the presence or absence of irradiation light, and thus are eliminated. Alternatively, as a sodium chloride aqueous solution, the adsorbing material inside may be irradiated with visible light to desorb copper ions. In this way, only copper ions can be recovered in the recovery solvent.
A copolymer using MDSA, such as P (MDSA-SPMA), has a phase transition temperature, and is hydrophobic at low temperatures and hydrophilic at high temperatures. Therefore, the adsorbing material can be taken out from the metal ion solution using the temperature difference. In this case, it can be insolubilized without a substrate or a crosslinking agent.

  Hereinafter, the present invention will be specifically described by way of examples. In addition, this invention is not limited by this Example. In the figure, the solid line display of the UV-visible absorption spectrum is in a dark place, and the dotted line display is after irradiation with visible light. Unless otherwise specified, the spectrum measurement was performed at room temperature.

<Synthesis of Spiropyran Methacrylate (SPMA)>
(1) As spiropyran, 1 ′, 3 ′, 3′-trimethyl-6-hydroxyspiro (2H-1-benzopyran-2,2′-indole) 4.72 g (0.0161 mol) (manufactured by ACROS ORGANICS, purity 99%, Fw 293.37, product number 42192-0050) was dissolved in 28.3 ml of toluene (manufactured by Kanto Chemical Co., Ltd. (used after distillation), special grade, purity 99.5%, boiling point 110.625 ° C.). .
(2) Methacrylic acid chloride (manufactured by ACROS ORGANICS, 760 mmHg, boiling point 95-96 ° C.) 1.84 g (0.0176 mol) was dissolved in 14.2 ml of toluene (same as above).
(3) Separately, 1.79 g (0.0114 mol) of triethylamine (hereinafter referred to as TEA) (manufactured by Wako Pure Chemical Industries, Ltd. (used after distillation), purity 99%, product number 202-02646) was prepared. In addition, ammonia (manufactured by Kanto Chemical Co., Inc., purity: 28.0 to 30.0%, product number: 01266-00) 400 ml of pure water (100 ml solution) was prepared as a unit, and 5 units were prepared.

(4) Into the two-necked flask, the toluene solution of spiropyran obtained in (1) above and the TEA in (3) above are charged. One of the two-necked flask has a ball cooler and the other. A cylindrical separatory funnel was attached to the mouth. While keeping the two-necked flask at 60 ° C., the toluene solution of methacrylic acid chloride of (2) above was dropped little by little with a cylindrical separatory funnel, and then reacted for 24 hours. The hydrochloric acid generated by this reaction was neutralized with TEA. After 24 hours, in order to remove unreacted methacrylic acid chloride and TEA from the reaction solution, the reaction solution was diluted with 100 ml of toluene, then transferred to a separatory funnel, and 1 unit of the aqueous ammonia solution (3) was added. . The separatory funnel was shaken and allowed to stand to take out the lower ammonia aqueous solution, 1 unit of the remaining ammonia aqueous solution (3) was added, and the liquid separation was repeated 5 times in the same manner.
(5) 100 ml of pure water was added instead of the aqueous ammonia solution, and the liquid separation was repeated a total of 5 times until the pH reached 7.
(6) Toluene was evaporated from the upper layer of the separatory funnel by an evaporator, and then dried under reduced pressure. The brown solid thus obtained was dissolved in dichloromethane and subjected to column chromatography to separate impurities. The column was silica gel (manufactured by Kanto Chemical Co., Ltd., product number: 9385-4M, Rf: 0.86), and the developing solvent was dichloromethane.
(7) The liquid discharged from the column was evaporated with an evaporator and then dried under reduced pressure, and the SPMA monomer, 1 ′, 3 ′, 3′-trimethyl-6- (methacryloyloxy) spiro (2H- 1.11 g (yield 23.5%) of 1-benzopyran-2,2′-indole) was obtained.

<Synthesis of Spiropyran Acrylate (SPAA)>
In the same manner except that 2.91 g (0.0322 mol) of acrylic acid chloride was used instead of methacrylic acid chloride, the SPAA monomer, 1 ′, 3 ′, 3′-trimethyl-6- ( 1.34 g (yield 24.0%) of (acryloyloxy) spiro (2H-1-benzopyran-2,2′-indole) was obtained.

  TMAEACl (Kojin Co., Ltd., product name DMAEA-Q) and MSDA (Aldrich, product number: 537284-50G) were prepared.

<Synthesis Example 1 Copolymer P (TMAEACl-SPAA)>
In order to correspond to a polymerization molar ratio of 98: 2, 4.9 × 10 ⁻³ mol (657 μl) of the above TMAEACl, 1.0 × 10 ⁻⁴ mol (34.7 mg) of SPAA monomer, and ethanol were added. 2 ml of a polymerization initiator AIBN 13.7 mg (8.3 × 10 ⁻⁵ mol) was prepared.

  TMAEACl, SPAA and ethanol were put into a sample bottle, and pure nitrogen was flowed into the bottle for 1 hour while stirring to remove moisture and air from the bottle. AIBN was added and stirred for an additional 30 minutes with nitrogen flow. The temperature in the bottle was raised to 60 ° C. in an oil bath and the reaction was continued for 1.5 hours while flowing nitrogen, and then hydroquinone was added as a polymerization inhibitor to stop the reaction.

The reaction product in the bottle was precipitated and purified by dropwise addition into a large amount of acetone. This precipitate was filtered off with a filter paper and dried under reduced pressure to obtain a copolymer P (TMAEACl-SPAA) (yield 58.7%). When the molar ratio of each segment in this copolymer was calculated from the result of the integral value of ¹ H-NMR, TMAEACl: SPAA was 98: 2.

<Synthesis Example 2 Copolymer P (MDSA-SPMA)>
0.03 × 10 ⁻³ mol of SPMA, 2.97 × 10 ⁻³ mol of MDSA, 2.0 ml of 2,2,2-trifluoroethanol, and 5.0 × 10 ⁻⁵ mol of AIBN were prepared. The copolymer P (MDSA-SPMA) was obtained in a yield of 56% and a polymerization molar ratio of 99: 1 in the same manner as in Synthesis Example 1 except that the initial stirring was 30 minutes and the reaction at 60 ° C. was 3.5 hours. Obtained.

<Synthesis Example 3 Copolymer P (MDSA-SPMA) Gel>
SPMA 0.05 × 10 ⁻³ mol, MDSA 4.85 × 10 ⁻³ mol, 2,2,2-trifluoroethanol 2.0 ml, N, N′-methylenebisacrylamide (hereinafter referred to as MBAAm). ) 0.1 × 10 ⁻³ mol and AIBN 8.4 × 10 ⁻⁵ mol. The reaction was conducted in the same manner as in Synthesis Example 2 except that the reaction at 60 ° C. was changed to 3 hours.
The gel-like contents after completion of the reaction were poured into a mold and heated at 60 ° C.
The gel obtained by solidification by heating is peeled off from the mold, purified by immersing in methanol for 1 week, further immersed in ultrapure water for 1 week, and then vacuum dried to copolymer P (MDSA-SPMA). A gel was obtained. The polymerization molar ratio was MDSA: SPMA: MBAAm = 97: 1: 2. This gel was insoluble in water.

(Example 1 Metal ion selectivity and photoresponsiveness of copolymer)
An aqueous solution having a concentration of 0.1 mM of copolymer P (TMAEACl-SPAA) having a polymerization ratio of 98: 2 obtained in Synthesis Example 1 was prepared, and CuCl ₂ , ZnCl ₂ , NiCl ₂ , CoCl ₂ , and CdCl ₂ were further added. These were added separately so that the molar concentration of each metal was 1 mM. FIG. 1A shows the ultraviolet-visible absorption spectra of these six types of aqueous solutions containing no addition of metal salt in the dark and after irradiation with visible light. An absorption band derived from a spiropyran ring-opened product (merocyanine structure) was observed at around 530 nm in the aqueous copolymer solution to which no metal salt was added in the dark. Since the solution containing each metal chloride also showed the same absorption band, it was found that the metal ions were hardly complexed. When these were irradiated with visible light, the absorption band was attenuated as shown by the dotted line, and it was confirmed that the ring was closed.

Sodium chloride was further added to these six kinds of aqueous solutions so as to become a 3 wt% solution. The ultraviolet-visible absorption spectrum of each solution is shown in FIG. From this, in the Cu (II) solution, an absorption band derived from a complex of SPAA and copper ions opened in the vicinity of 410 to 420 nm was observed in the dark, but in the other four types of metal solutions, FIG. Similar to a), an absorption band derived from a free ring-opened compound not complexed with metal ions was observed.
Further, when these solutions were irradiated with visible light, the absorption was attenuated as indicated by the dotted line in the figure. Absorption appeared again in the dark after stopping visible light irradiation. This confirmed reversible SPAA photoresponsiveness.

(Example 2 Copper ion adsorptivity of copolymer by sodium chloride concentration)
An aqueous solution of P (TMAEACl-SPAA) and CuCl ₂ was prepared so that the molar concentration ratio of SPAA: Cu (II) was 1:10 (Cu (II) molar concentration 1 mM). To this, sodium chloride was added to 0, 1, 3, 5, 10, and 26 wt%. Each ultraviolet-visible absorption spectrum in the dark is shown in FIG. The strength of the absorption band of the copper complex increases as the concentration increases up to 10% of sodium chloride, but the strength of the absorption band of the copper complex is almost equal between 10 wt% and the saturation concentration of 26 wt%. It was found that even if it was 5 wt%, about 3/4 of copper ions in the case of 10 wt% can be adsorbed, and if the sodium chloride concentration is 1 wt%, the absorption band can be detected.

(Example 3 Copper ion adsorptivity of copolymer depending on copper ion concentration)
In a saturated saline solution (26 wt%), P (TMAEACl-SPAA) and CuCl ₂ are mixed at a molar ratio of SPAA: Cu (II) of 1: 1, 1: 1/3, 1: 1/5, 1: 1/10, 1: 0 was added (SPAA molar concentration 0.1 mM). Each ultraviolet-visible absorption spectrum in the dark is shown in FIG. When the Cu (II) concentration is low, the absorption band of the copper complex is also attenuated. When the molar concentration of Cu (II) ions is 1/10 or less of SPAA, it is difficult to detect the absorption band. I found that I could detect it.

Example 4 Metal Ion Selectivity of Copolymer
A solution was prepared by adding the copolymer P (MDSA-SPMA) having a polymerization molar ratio of 99: 1 obtained in Synthesis Example 2 above to an aqueous solution of 1 wt% sodium chloride at a concentration of 0.1 mM. Further, CuCl ₂ , ZnCl ₂ , NiCl ₂ , CoCl ₂ , and CdCl ₂ were added separately so that each metal had a molar concentration of 1 mM. The pH of these six solutions containing no metal salt added was 8.5. The ultraviolet-visible absorption spectrum in these dark places and after irradiation with visible light is shown together in FIG. As a result, in the Cu (II) solution, an absorption band derived from a complex of SPMA and a copper ion ring-opened at around 416 nm was observed in the dark. However, in the other four types of metal solutions, a complex with a metal ion was observed. An absorption band derived from an almost free ring-opened product that was not formed was observed at 530 nm. From this, it can be seen that only Cu (II) ions are selectively complexed and adsorbed to the merocyanine structure opened in the dark in the saline solution.
When each of these solutions was irradiated with visible light, the absorption band was attenuated as shown by the dotted line, and it was confirmed that the ring was closed. Absorption appeared again when the visible light irradiation was stopped. Thereby, reversible photoresponsiveness of SPMA was confirmed.

(Example 5 Metal ion selectivity of copolymer)
In this example, Pb (II) ions, which are known to have high complexing ability with spiropyran among metal ions, were compared with Cu (II) ions.
A solution was prepared in the same manner as in Example 4 except that Pb (ClO ₄ ) ₂ and Cu (ClO ₄ ) ₂ were used instead of the metal chloride. The pH of the three types of solutions containing no metal salt added was 8.5. The ultraviolet-visible absorption spectrum is shown in FIG.
In the solution containing Pb (II) ions, as in the solution containing Cu (II) ions, an absorption band was observed near 415 nm derived from the metal complex in the dark, but the absorbance ratio was less than 1/2. there were. When these solutions were irradiated with visible light, the absorption bands were all attenuated as indicated by the dotted line.

  For comparison, a copolymer of 1 ′, 3 ′, 3′-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2′-indole) and N-isopropylacrylamide (hereinafter, An ultraviolet-visible absorption spectrum measured in the same manner as in Example 5 above using an aqueous solution of P (SPA-NIPAAm) (without salt) is shown in FIG. The absorption band derived from the metal complex in the dark was an absorbance with almost the same intensity in the Pb (II) solution and the Cu (II) solution. Thereby, it is considered that the copolymer P (MDSA-SPMA) in the sodium chloride aqueous solution is selectively reversibly complexed with Cu (II) ions to some extent.

(Example 6 Metal ion selectivity of copolymer gel)
The gel of MDSA: SPMA: MBAAm = 97: 1: 2 obtained in Synthesis Example 3 was molded into the size of the inner wall of the spectrum measurement cell where the measurement light hits.
a) (SPMA amount contained in the gel formed above): 1 wt% of sodium chloride so that the molar ratio of 1:10 CuCl _{2 in} the liquid injected into the measurement cell is 1:10 CuCl ₂ was dissolved in an aqueous solution. The CuCl ₂ concentration was 10 mM.
b) Similarly, ZnCl ₂ was dissolved in an aqueous solution of 1 wt% sodium chloride. The ZnCl ₂ concentration was 8.4 mM.
c) For comparison, an aqueous solution (blank) of 1 wt% sodium chloride not containing metal ions was prepared.
The pH of these solutions was 8.5.
After injecting the specified amount of a), b), and c) into the three cells with the above-formed gel adhered to the inner wall and holding at room temperature for 6 hours in a dark place, The UV-visible absorption spectrum was measured. Thereafter, the spectrum after irradiation with visible light was also measured. The results are shown in FIG.
When each of these solutions was irradiated with visible light, the absorption band was attenuated as indicated by the dotted line. Absorption appeared again when the visible light irradiation was stopped. Thereby, the photoresponsiveness of the reversible SPMA copolymer gel was confirmed. For reference, the difference in absorbance between the two spectra under the dark place and light irradiation was calculated. This is shown in the inner frame of FIG.
Therefore, it is considered that the gel P (MDSA-SPMA-MBAAm) selectively adsorbs copper ions as shown in FIG.

表１から、塩化ナトリウム０．１ｗｔ％の水溶液の場合、ＭＤＳＡ：ＳＰＭＡ重合モル比が９９：１では４５℃以上で親水性を示し、重合モル比が９５：５では３５℃以上であればよいので、より低温で銅（II）イオンを吸着できることがわかる。 (Example 7 Phase transition temperature of copolymer)
For example, P (MDSA-SPMA) is hydrophobic and turbid at low temperatures as shown in FIG. Therefore, the phase transition temperature of P (MDSA-SPMA) was detected by turbidity as follows.
P (MDSA-SPMA) was dissolved at a concentration of 0.04 wt% in pure water and an aqueous sodium chloride solution (0.1 wt% and 1 wt%), and the light transmittance at 700 nm (wavelength not affected by absorption of spiropyran) was measured. The temperature at which the light transmittance was 90% or less was defined as the phase transition temperature.
For reference, P (MDSA) was similarly measured by dissolving in pure water and a sodium chloride aqueous solution. In all cases, the pH is not adjusted. The results are shown in Table 1. Above the phase transition temperature, all solutions were transparent hydrophilic solutions.

From Table 1, in the case of a 0.1 wt% sodium chloride aqueous solution, MDSA: SPMA polymerization molar ratio of 99: 1 indicates hydrophilicity at 45 ° C. or higher, and polymerization molar ratio of 95: 5 may be 35 ° C. or higher. Therefore, it can be seen that copper (II) ions can be adsorbed at a lower temperature.

It is the graph which measured the ultraviolet visible absorption spectrum of copolymer P (TMAEAC1-SPAA) in the solution containing the various metal ions of Example 1 of the present invention, (a) before adding sodium chloride to the solution, (b) Is a spectrum in the dark where sodium chloride is dissolved. It is the graph which measured the ultraviolet visible absorption spectrum of the copolymer P (TMAEAC1-SPAA) under the dark place with respect to the sodium chloride density | concentration of Example 2 of this invention. It is the graph which measured the ultraviolet visible absorption spectrum of the copolymer P (TMAEACl-SPAA) in the dark place with respect to the ratio of SPAA: copper (II) ion of Example 3 of this invention. It is the graph which measured the ultraviolet visible absorption spectrum of copolymer P (MDSA-SPMA) in the solution containing various metal ions and sodium chloride in Example 4 of the present invention. It is the graph which measured the ultraviolet visible absorption spectrum of the solution containing Pb (II) ion and Cu (II) ion in Example 5 of this invention, (a) is a copolymer P (MDSA-SPMA), Sodium chloride is included, and (b) is P (SPA-NIPAAm). In Example 6 of this invention, (a) is the graph which measured the ultraviolet visible absorption spectrum of the copolymer gel P (MDSA-SPMA-MBAAA) in the solution containing various metal ions and sodium chloride, (b) It is a chemical formula showing the behavior. It is a chemical formula which shows the phase transition of P (MDSA-SPMA) of this invention.

Claims (15)

And photoresponsive compounds showing reversible by the presence of chloride ions, the light irradiation metastasis adsorption and desorption of copper (II) ions with sodium ions and copper (II) metal ion solution containing ions,
Look-containing copolymers by copolymerizing a monomer component containing a quaternized amine compounds,
The photoresponsive copper ion adsorbing material, wherein the photoresponsive compound is a compound having a group represented by the following formula (I) or (II) and a polymerizable ethylenically unsaturated bond .

(In the formulas (I) and (II), X is a carbon atom to which one hydrogen atom is bonded, or a nitrogen atom, Y is an oxygen atom or a sulfur atom. R ₁ and R ₂ are independently a hydrogen atom or alkyl. And R ₃ is an alkyl group.) The photoresponsive copper ion according to claim 1, wherein the copolymer selectively adsorbs copper (II) ions in a dark place from a metal ion solution containing the chlorine ions, sodium ions, and copper (II) ions. Adsorption material. The photoresponsive copper ion adsorbing material according to claim 1 or 2, wherein the quaternized amine compound has a group represented by the following formula (IV) and a polymerizable ethylenically unsaturated bond.

The photoresponsive copper ion adsorbing material according to claim 1 or 2, wherein the quaternized amine compound has a group represented by the following formula (V) and a polymerizable ethylenically unsaturated bond.

The copolymer is 1 ', 3', 3'-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2'-indole) or 1 ', 3', 3'-trimethyl- 6- (methacryloyloxy) spiro (2H-1-benzopyran-2,2′-indole);
N, N, N-trimethyl -N- acryloyloxyethyl ammonium chloride or N, N, N-trimethyl -N- methacrylonitrile comprising a copolymerized monomer component containing a acryloyloxyethyl ammonium chloride claim 1-3 Any one of the photoresponsive copper ion adsorption material of description. The copolymer is 1 ', 3', 3'-trimethyl-6- (acryloyloxy) spiro (2H-1-benzopyran-2,2'-indole) or 1 ', 3', 3'-trimethyl- 6- (methacryloyloxy) spiro (2H-1-benzopyran-2,2′-indole);
[2- (acryloyloxy) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide or
The photoresponsiveness according to any one of claims 1 , 2 , and 4, wherein a monomer component containing [2- (methacryloyloxy) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide is copolymerized. Copper ion adsorption material. The photoresponsive copper ion adsorbing material according to any one of claims 1 to 6 , wherein the copolymer is supported on a substrate. The photoresponsiveness according to claim 7 , wherein the substrate is selected from the group consisting of glass, metal oxide, silicon oxide, silica gel, diatomaceous earth, a styrene polymer, an acrylic acid polymer, and a methacrylic acid polymer. Copper ion adsorption material. The photoresponsive copper ion adsorbing material according to any one of claims 1 to 8 , further comprising a crosslinking agent or a coupling agent in the monomer component. Fibers, photoresponsive copper ion adsorption material according to any one of claims 7-9, wherein the copolymer tubules were fine or is supported. Using photoresponsive copper ion adsorption material according to claim 1-10, copper (II) ions from the metal ion solution containing chloride ions and sodium ions, selectively copper (II) ions, A method for recovering copper ions, comprising recovering into a recovery solvent. A step of adsorbing the copolymer of the photoresponsive copper ion adsorbing material and copper (II) ions by complex formation in the dark in the presence of chlorine ions and sodium ions;
The method for recovering copper ions according to claim 11 , further comprising a step of desorbing copper (II) ions from the copolymer in a recovery solvent. The metal ion solution, the chlorine ions and sodium ions, sodium chloride reduced concentration, copper ion collection method according to claim 11 or 12, wherein at most 10 wt%. The method for recovering copper ions according to claim 12 , wherein in the step of desorbing the copper (II) ions from the copolymer, the recovery solvent is water not containing sodium chloride. 13. The method for recovering copper ions according to claim 12 , wherein in the step of desorbing the copper (II) ions from the copolymer, the recovery solvent is an aqueous solution of sodium chloride, and the copper ions are desorbed by irradiation with visible light. .

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