Method for treating adsorption material

Abstract

Provided is a method for treating an adsorption material containing heavy metal ions adsorbed thereto, the method enabling reuse of a solution used in the treatment of the adsorption material. This method for treating an adsorption material comprises: bringing a first adsorption material containing heavy metal ions adsorbed onto an adsorption material into contact with a first solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions and having a pH of more than 7 to obtain a second adsorption material in which at least some of the heavy metal ions are desorbed and the alkali metal ions or the like are attached and a second solution containing the heavy metal ions; bringing the second adsorption material into contact with a third solution having a pH of less than 7 to obtain a third adsorption material in which at least some of the alkali metal ions or the like are eliminated and a fourth solution containing the alkali metal ions or the like; subjecting the second solution to electrolysis to reduce at least some of the heavy metal ions to metal and obtain a fifth solution in which at least some of the heavy metal ions are eliminated; and subjecting the fourth solution to electrodialysis by using an electrodialyzer provided with at least one of a cation exchange membrane and an anion exchange membrane to obtain a sixth solution in which at least some of the alkali metal ions or the like are eliminated and a seventh solution containing the eliminated alkali metal ions or the like.

Description

Method for processing adsorbent materials

[0001] The present invention relates to a method for processing adsorbent materials.

[0002] As a method for reusing chemical treatment solutions used in various chemical processes, metal ion adsorption treatment using adsorbent materials such as ion exchange resins is known. By regenerating used adsorbent materials, they can be utilized efficiently. However, the treatment solution used to regenerate the adsorbent material can become new waste, and further reduction of the environmental burden is required. For example, Japanese Patent Publication No. 09-122643 describes a method for separating and reusing acid and alkaline solutions from a solution used to regenerate ion exchange resin by electrodialysis treatment using a bipolar membrane apparatus equipped with a cation exchange membrane, an anion exchange membrane, and a bipolar membrane.

[0003] However, when the chemical treatment solution to be adsorbed contains heavy metal ions, deterioration of the bipolar membrane apparatus may occur during electrodialysis. One aspect of the present invention aims to provide a method for treating adsorbent material on which heavy metal ions have been adsorbed, which enables the reuse of the solution used to treat the adsorbent material.

[0004] The first embodiment is a method for processing an adsorbent material comprising at least one selected from the group consisting of ion exchange resins and chelate resins. The method for processing the adsorbent material involves contacting a first adsorbent material on which heavy metal ions are adsorbed with a first solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions and having a pH greater than 7, thereby obtaining a second adsorbent material on which at least a portion of the heavy metal ions are desorbed and at least one selected from the group consisting of alkali metal ions and ammonium ions is attached, and a second solution containing heavy metal ions; and contacting the second adsorbent material with a third solution having a pH less than 7, thereby obtaining a third adsorbent material from which at least a portion of at least one selected from the group consisting of alkali metal ions and ammonium ions has been removed, and alkali metal ions The method includes: obtaining a fourth solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions; electrolyzing the second solution to reduce at least a portion of the heavy metal ions to metals to obtain a fifth solution from which at least a portion of the heavy metal ions has been removed; and electrodialysis the fourth solution using an electrodialysis apparatus equipped with at least one cation exchange membrane and an anion exchange membrane to obtain a sixth solution from which at least a portion of at least one selected from the group consisting of alkali metal ions and ammonium ions has been removed, and a seventh solution containing at least one selected from the group consisting of the removed alkali metal ions and ammonium ions.

[0005] In one embodiment, the method for treating the adsorbent material may include reusing at least a portion of the fifth solution as at least a portion of the first solution, reusing at least a portion of the seventh solution as at least a portion of the first solution, and reusing at least a portion of the sixth solution as at least a portion of the third solution.

[0006] According to one aspect of the present invention, a method for treating an adsorbent material on which heavy metal ions have been adsorbed is provided, which allows for the reuse of the solution used to treat the adsorbent material.

[0007] This is a schematic cross-sectional view showing an example of an electrodialysis apparatus. This is a schematic cross-sectional view showing another example of an electrodialysis apparatus. This is a schematic perspective view showing an example of an electrodialysis apparatus used in the embodiment.

[0008] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. Furthermore, the content of each component in a composition refers to the total amount of multiple substances present in the composition, unless otherwise specified, if multiple substances corresponding to each component exist in the composition. In addition, the upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges. Furthermore, in this specification, the hydrogen ion concentration (pH) is measured at room temperature (25°C) using a commonly used pH meter. Embodiments of the present invention will now be described in detail. However, the embodiments shown below are illustrative of methods for processing adsorbent materials to embody the technical concept of the present invention, and the present invention is not limited to the methods for processing adsorbent materials shown below.

[0009] Method for Processing Adsorbent Material The method for processing an adsorbent material according to this embodiment is a method for processing an adsorbent material that includes at least one selected from the group consisting of ion exchange resins and chelate resins. The method for processing an adsorbent material includes a first step of contacting a first adsorbent material, which is formed when heavy metal ions are adsorbed onto an adsorbent material, with a first solution containing at least one monocation (hereinafter sometimes abbreviated as "alkali metal ions, etc.") selected from the group consisting of alkali metal ions and ammonium ions, and having a pH greater than 7, to obtain a second adsorbent material to which at least a portion of the heavy metal ions are desorbed and alkali metal ions, etc. are attached, and a second solution containing heavy metal ions, and a second step of contacting the second adsorbent material with a third solution having a pH less than 7 to obtain at least one of the alkali metal ions, etc. The method includes: a second step of obtaining a third adsorbent material from which a portion has been removed and a fourth solution containing alkali metal ions, etc.; a third step of electrolyzing the second solution to reduce at least a portion of the heavy metal ions to metal to obtain a fifth solution from which at least a portion of the heavy metal ions has been removed; and a fourth step of electrodialysis of the fourth solution using an electrodialysis apparatus equipped with at least one ion exchange membrane selected from the group consisting of cation exchange membranes and anion exchange membranes to obtain a sixth solution from which at least a portion of the alkali metal ions, etc. has been removed and a seventh solution containing the removed alkali metal ions, etc. The method for processing the adsorbent material may be, for example, a method for regenerating or reusing the adsorbent material, or a method for regenerating or reusing the processing solution used in the method for processing the adsorbent material. Furthermore, the method for processing the adsorbent material may also be a method for recovering heavy metal ions adsorbed on the adsorbent material.

[0010] In the method for processing adsorbent materials, the adsorbent material on which heavy metal ions have been adsorbed is regenerated. Here, the regeneration of the adsorbent material means removing the heavy metal ions adsorbed by the adsorbent material and returning it to a state in which it can be used again for adsorbing heavy metal ions. In the processing method of this embodiment, the process is divided into two stages: a desorption process of heavy metal ions from the adsorbent material using a solution containing alkali metal ions, etc., and a process to remove the alkali metal ions, etc., captured by the adsorbent material as a result of the desorption process. The removal of alkali metal ions, etc., from the adsorbent material is carried out by eluting the alkali metal ions, etc., using an acidic solution. Therefore, in the method for processing adsorbent materials, a solution containing heavy metal ions and a solution containing alkali metal ions, etc., are discharged, but each solution is appropriately processed and reused, so the adsorbent material can be regenerated efficiently.

[0011] In the adsorbent material treatment method, the second solution containing heavy metal ions is subjected to electrolysis to obtain a fifth solution in which at least a portion of the heavy metal ions are reduced to metal and removed. At least a portion of the fifth solution can be reused as at least a portion of the first solution used in a regeneration treatment to desorb heavy metal ions from the adsorbent material to which heavy metal ions have been adsorbed. The fourth solution containing alkali metal ions, etc., is subjected to electrodialysis to separate it into a sixth solution from which at least a portion of the alkali metals, etc., have been removed, and a seventh solution containing alkali metal ions, etc. The sixth solution from which the alkali metal ions, etc., have been removed can be reused as at least a portion of the third solution used in a regeneration treatment of the adsorbent material to which alkali metal ions, etc., have been attached. The seventh solution containing alkali metal ions, etc., can be reused as at least a portion of the first solution used in a regeneration treatment to desorb heavy metal ions from the adsorbent material to which heavy metal ions have been adsorbed. In this way, the fourth solution produced in the regeneration treatment of the adsorbent material can be reused in the adsorbent material treatment method without being discharged as waste liquid.

[0012] In the first step, the first adsorbent material is brought into contact with the first solution. By bringing the first adsorbent material, on which heavy metal ions are adsorbed, into contact with the first solution, which contains alkali metal ions and has a pH greater than 7, at least a portion of the heavy metal ions are desorbed from the first adsorbent material, and a second adsorbent material to which alkali metal ions and the like are attached can be obtained. The heavy metal ions desorbed from the adsorbent material dissolve in the first solution, and a second solution containing heavy metal ions and alkali metal ions and the like is produced.

[0013] The heavy metal ions adsorbed on the adsorbent material are not particularly limited as long as they are heavy metal ions that can be dissolved in an alkaline aqueous solution. Examples of heavy metal ions include zinc ions, tin ions, and lead ions, and may contain at least one selected from the group consisting of zinc ions, tin ions, and lead ions, and may contain at least tin ions.

[0014] The adsorbent material is not particularly limited, as long as it is capable of adsorbing heavy metal ions contained in the solution to be treated. Here, "capable of adsorption" means that heavy metal ions can be localized on the adsorbent material through interaction between the functional groups of the adsorbent material and the heavy metal ions. Examples of interactions between the functional groups of the adsorbent material and the heavy metal ions include ionic bonding, coordination bonding, hydrogen bonding, etc., and combinations thereof may also be used. An adsorbent material capable of adsorbing heavy metal ions may include, for example, at least one adsorbent material selected from the group consisting of ion exchange resins and chelate resins. From the viewpoint of selectivity for heavy metal ions, the adsorbent material may include at least one chelate resin.

[0015] The ion exchange resin may be a resin having a functional group capable of forming ionic bonds with heavy metal ions, and may be a cation exchange resin. Examples of functional groups capable of forming ionic bonds, i.e., salts, with heavy metal ions include sulfo groups and carboxyl groups. The adsorbent material may contain only one type of ion exchange resin, or a combination of two or more types. A specific example of an ion exchange resin is DIAION. （ＴＭ） SK1B (manufactured by Mitsubishi Chemical Corporation), IR120B (manufactured by Organo Corporation), Duolite （ＴＭ）Examples include C20 (manufactured by Sumika Chemtex Co., Ltd.).

[0016] The chelate resin may be a resin having a functional group capable of forming chelates with heavy metal ions. Examples of compounds from which chelate-forming functional groups are derived include iminodiacetic acid, polyamines (e.g., aliphatic polyamines), alkyl sulfides, alkyl or aryl sulfonic acids, alkyl or arylamines, alkyl or arylphosphonic acids, N-methylglucamine, aminophosphate, amidoxime, bispicolylamine, thiourea (isothiouronium), and semithiocarbamic acid. The chelate resin may be a resin containing a functional group derived from at least one selected from the group consisting of N-methylglucamine, aminophosphate, iminodiacetic acid, and polyamine, and may be a resin having at least a functional group derived from aminophosphate. Examples of resins that serve as the base material for the chelate resin include cellulose, polystyrene resin, and styrene-divinylbenzene copolymer. The chelate resin contained in the adsorbent may be only one type, or a combination of two or more types.

[0017] A specific example of a chelating resin is chelating fiber. （Ｒ） GRY-HW, Kirest Fiber （Ｒ） GRY-H (both manufactured by KILEST), DIAION （ＴＭ） CRB03, CRB05 (both manufactured by Mitsubishi Chemical Corporation), Duolite （ＴＭ） Chelate resins having functional groups derived from N-methylglucamine, such as ES371N (manufactured by Sumika Chemtex Co., Ltd.); Muromac XMS-5416 (manufactured by Muromachi Chemical Co., Ltd.), AMBERSEP IRC747UPS (manufactured by Organo Corporation), Duolite （ＴＭ） Examples include chelate resins having functional groups derived from aminophosphates, such as C467 (manufactured by Sumika Chemtex Co., Ltd.).

[0018] The first adsorbent material may be, for example, an adsorbent material obtained by bringing an adsorbent material into contact with a chemical treatment solution containing heavy metal ions, so that at least a portion of the heavy metal ions contained in the chemical treatment solution are adsorbed onto the adsorbent material. The chemical treatment solution may be, for example, plating wastewater used in metal plating treatment, or plating wastewater generated by washing metal-plated articles with water. By adsorbing heavy metal ions in the chemical treatment solution onto the adsorbent material, heavy metal ions in the chemical treatment solution can be recovered, and components other than heavy metal ions can be efficiently recovered.

[0019] The chemical treatment solution may further contain, in addition to heavy metal ions, a complexing agent capable of forming complex ions with heavy metal ions. Examples of complexing agents that form complex ions include carboxylic acids, such as gluconic acid (including gluconolactone), citric acid, glutaric acid, succinic acid, malic acid, tartaric acid, lactic acid, acetic acid, malonic acid, and their salts or derivatives; phosphoric acids, such as tripolyphosphate, hydroxyethanediphosphonic acid, and their salts; sugars, such as sorbitol, mannitol, and their salts; amino acids, such as phenylalanine, glutamic acid, aspartic acid, alanine, glycine, and their salts; and HEDTA, EDTA, etc. The complexing agent may contain at least one selected from the group consisting of these, and may contain at least gluconic acid. The complexing agent may be used alone or in combination of two or more.

[0020] The contact between the chemical treatment liquid and the adsorbent material may be carried out by a batch method or a column method. The contact between the chemical treatment liquid and the adsorbent material by the batch method can be carried out, for example, by mixing the chemical treatment liquid and the adsorbent material and stirring as necessary. After the contact between the chemical treatment liquid and the adsorbent material by the batch method, the adsorbent material can be separated from the chemical treatment liquid by solid-liquid separation (for example, filtration) to obtain the treated first adsorbent material. Further, the contact between the chemical treatment liquid and the adsorbent material by the column method can be carried out, for example, by passing the chemical treatment liquid through a column filled with the adsorbent material. The number of times of passing the chemical treatment liquid through the column may be, for example, 1 or more and 100 or less, preferably 10 or more, or 60 or less. In the column method, the first adsorbent material can be obtained by separating the effluent from the column. When the chemical treatment liquid is passed through the column continuously, the number of passes is measured assuming that one pass is made when the amount of liquid corresponding to the total amount of the prepared chemical treatment liquid has passed through the column. The same applies to the following column methods.

[0021] The contact temperature between the chemical treatment liquid and the adsorbent material may be, for example, 20°C or higher and 30°C or lower, preferably 22°C or higher, or 28°C or lower. The contact time between the chemical treatment liquid and the adsorbent material in the case of the batch method may be, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more, or 24 hours or less. Also, the contact time in the case of the column method may be, for example, 1 hour or more and 5 hours or less, preferably 2 hours or more.

[0022] The first solution to be contacted with the first adsorbent material contains at least one monocation selected from the group consisting of alkali metal ions and ammonium ions. Examples of the alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, etc. The alkali metal ions contained in the first solution may contain at least one of sodium ions and potassium ions.

[0023] Examples of the ammonium ions include unsubstituted ammonium ions (NH<00000{08}><00000{09}>), protonated amines having 1 to 3 organic groups (NH[[ID=1{3}]]<00000{10}>[[ID=1{4}]]R（３－ｍ） H ＋ ), a quaternary ammonium cation substituted with four organic groups (NR ４ ＋ Examples include the following. Here, R represents an organic group, and m represents an integer from 0 to 2. Examples of organic groups in the substituted ammonium ion include alkyl groups having 1 to 6 carbon atoms. The number of carbon atoms in the alkyl group may preferably be 1 to 3. The organic group in the substituted ammonium ion may have further substituents. Examples of substituents in the organic group include hydroxyl groups and alkoxy groups having 1 to 4 carbon atoms.

[0024] The concentration of alkali metal ions, etc., contained in the first solution may be, for example, 0.04 mol / L or more and 2 mol / L or less, preferably 0.1 mol / L or more and 1 mol / L or less, or 0.2 mol / L or more and 0.8 mol / L or less. The pH of the first solution may be, for example, greater than 7, preferably 9 or more, 12 or more, or 13 or more. The pH of the first solution may be 14 or less, preferably 13.8 or less. The volume of the first solution to be brought into contact with the first adsorbent material may be, on a volume basis, for example 2 to 20 times the volume of the first adsorbent material, preferably 3 to 12 times, or 4 to 8 times.

[0025] The first solution may contain heavy metal ions as needed. Examples of heavy metal ions include zinc ions, tin ions, and lead ions, and may contain at least one selected from the group consisting of zinc ions, tin ions, and lead ions, and may contain at least tin ions. The heavy metal ions contained in the first solution may be components derived from the fifth solution that is reused. If the first solution contains heavy metal ions, the concentration of heavy metal ions contained in the first solution may be, for example, 0.01 mol / L or more and 0.4 mol / L or less, preferably 0.02 mol / L or more, or 0.08 mol / L or less.

[0026] The first solution can be prepared, for example, by dissolving an alkali metal hydroxide such as sodium hydroxide in water. The first solution may also be prepared by including at least a portion of the fifth solution, which will be described later, and at least a portion of the seventh solution. Furthermore, the first solution may consist of at least one of the fifth solution and the seventh solution. By including at least a portion of the regenerating solution selected from the fifth solution and the seventh solution in the first solution, the amount of the first solution that needs to be newly prepared when processing the adsorbent material can be reduced.

[0027] Contact between the first solution and the first adsorbent may be carried out by a batch method or by a column method. Contact between the first solution and the first adsorbent by a batch method can be carried out, for example, by mixing the first solution and the first adsorbent and stirring as necessary. After contact between the first solution and the first adsorbent by a batch method, a second adsorbent with alkali metal ions etc. attached after the first step treatment and a second solution from which heavy metal ions have been eluted can be obtained by solid-liquid separation (e.g., filtration). Contact between the first solution and the first adsorbent by a column method can be carried out, for example, by passing the first solution through a column packed with the first adsorbent. The number of times the first solution is passed through the column may be, for example, 1 to 100 times, preferably 5 to 50 times, or 50 times or 20 times or 20 times or 30 times. In the column method, the second solution is obtained as the effluent from the column, and the second adsorbent is obtained inside the column.

[0028] The contact temperature between the first solution and the first adsorbent material may be, for example, 20°C to 30°C, preferably 22°C or higher, or 28°C or lower. The contact time between the first solution and the first adsorbent material may be, for example, 0.2 hours to 48 hours, preferably 0.5 hours or higher, or 24 hours or lower, in the case of the batch method. In the case of the column method, the contact time may be, for example, 0.2 hours to 5 hours, preferably 0.5 hours to 2 hours.

[0029] In the second adsorbent material, alkali metal ions and the like are attached to the adsorbent material. The alkali metal ions and the like may be attached to the adsorbent material by interacting with the functional groups of the adsorbent material through ionic bonding or the like. In the second solution, heavy metal ions that were adsorbed on the first adsorbent material are desorbed and dissolved. The concentration of heavy metal ions in the second solution may be, for example, 0.01 mol / L or more and 0.4 mol / L or more, and preferably 0.03 mol / L or more and 0.16 mol / L or less. The content of heavy metal ions in the second solution may be, for example, 90% or more and preferably 95% or more relative to the content of heavy metal ions in the first adsorbent material. The pH of the second solution may be, for example, 8 or more and 14 or less, and preferably 12 or more and 13.5 or less.

[0030] In the second step, the second adsorbent material is brought into contact with the third solution. By bringing the second adsorbent material, to which alkali metal ions and the like are attached, into contact with the third solution, which has a pH less than 7, alkali metal ions and the like are eluted from the second adsorbent material into the third solution, and a third adsorbent material is obtained from which at least a portion of the alkali metal ions and the like have been removed. The alkali metal ions and the like removed from the second adsorbent material dissolve in the third solution, and a fourth solution is obtained that contains alkali metal ions and the like along with anions derived from acidic compounds.

[0031] The pH of the third solution may be, for example, less than 7, preferably 5 or less, or 3 or less. The pH of the third solution may be, for example, 0 or more, preferably 0.5 or more. The amount of the third solution to be brought into contact with the second adsorbent material may be, for example, 1 to 100 times the amount of the second adsorbent material, preferably 2 to 10 times.

[0032] The third solution may be, for example, an aqueous solution of an acidic compound. Examples of acidic compounds include sulfuric acid, alkanesulfonic acid, and alkanecarboxylic acid. The number of carbon atoms in the alkyl group constituting the alkanesulfonic acid or alkanecarboxylic acid may be, for example, 1 to 6, preferably 1 to 3. The concentration of the acidic compound contained in the third solution may be, for example, 0.04 mol / L or more and 2 mol / L or less, preferably 0.1 mol / L or more and 1 mol / L or less.

[0033] The third solution may contain alkali metal ions or the like as necessary. Examples of the alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, and the like. The third solution may contain at least one of sodium ions and potassium ions. Further, the third solution may contain the above-mentioned ammonium ions. The alkali metal ions or the like contained in the third solution may be components derived from the sixth solution to be reused. When the third solution contains alkali metal ions or the like, the concentration of the alkali metal ions or the like contained in the third solution may be, for example, 0.02 mol / L or more and 1 mol / L or less, and preferably 0.5 mol / L or less.

[0034] The contact between the third solution and the second adsorbent may be carried out by a batch method or a column method. The contact between the third solution and the second adsorbent by the batch method can be carried out, for example, by mixing the third solution and the second adsorbent and stirring as necessary. After the contact between the third solution and the second adsorbent by the batch method, a third adsorbent from which at least a part of alkali metals or the like after the second-step treatment has been removed and a fourth solution in which alkali metal ions or the like are dissolved can be obtained by solid-liquid separation (for example, filtration). Further, the contact between the third solution and the second adsorbent by the column method can be carried out, for example, by passing the third solution through a column filled with the second adsorbent. The number of times of passing the third solution through the column may be, for example, 1 or more and 100 or less, and preferably 5 or more, or 50 or less or 20 or less. In the column method, a fourth solution is obtained as an effluent from the column, and a third adsorbent is obtained in the column.

[0035] The contact temperature between the third solution and the second adsorbent may be, for example, 20°C or more and 30°C or less, and preferably 22°C or more, or 28°C or less. The contact time between the third solution and the second adsorbent in the case of the batch method may be, for example, 1 hour or more and 48 hours or less, and preferably 2 hours or more, or 24 hours or less. Further, the contact time in the case of the column method may be, for example, 0.2 hours or more and 5 hours or less, and preferably 0.5 hours or more and 2 hours or less.

[0036] In the fourth solution, alkali metal ions and the like that adhered to the second adsorbent material are dissolved. The concentration of alkali metal ions and the like in the fourth solution may be, for example, 0.04 mol / L or more and 2 mol / L or less, and preferably may be 0.1 mol / L or more and 1 mol / L or less. Further, the fourth solution contains anions derived from the acidic compound contained in the third solution. The concentration of the anions in the fourth solution may be the same as that in the third solution. The pH of the fourth solution may be, for example, 0 or more and 6 or less, and preferably may be 1 or more and 5 or less.

[0037] Since the third adsorbent material obtained in the second step contains functional groups to which metal ions such as heavy metal ions and alkali metal ions are not adsorbed, for example, it can be reused by contacting it with a chemical treatment solution containing heavy metal ions to remove at least a part of the heavy metal ions from the chemical treatment solution.

[0038] In the third step, the second solution containing heavy metal ions is subjected to electrolysis treatment to reduce at least a part of the heavy metal ions to metal, and a fifth solution in which at least a part of the heavy metal ions is removed is obtained. By subjecting the second solution to electrolysis treatment to reduce heavy metal ions to elemental metal, the heavy metal can be recovered, and a fifth solution that can be reused as a part of the first solution can be obtained.

[0039] The electrolysis treatment of the second solution can be performed, for example, by introducing the second solution into an electrochemical device including a working electrode and a counter electrode and flowing a current with the working electrode as the cathode. Thereby, the heavy metal ions are reduced, and for example, elemental metal is deposited on the working electrode, and a working electrode with metal adhered thereto is obtained. The electrochemical device may include a working electrode chamber including a working electrode and a counter electrode chamber including a counter electrode, and the working electrode chamber and the counter electrode chamber may be separated by a diaphragm. The diaphragm may be one selected from the group consisting of an ion exchange membrane, a reverse osmosis membrane, and a nanofiltration membrane. The second solution is introduced into the working electrode chamber of the electrochemical device. A conductive ion-containing aqueous solution may be disposed in the counter electrode chamber of the electrochemical device. By disposing a conductive ion-containing aqueous solution in the counter electrode chamber, the heavy metal ions can be reduced more efficiently.

[0040] Examples of materials for the working electrode provided in the working electrode chamber include gold, platinum, platinum-clad titanium, silver, nickel, graphite, tin, titanium, iridium oxide, ruthenium oxide, copper, iron, and stainless steel. Examples of materials for the counter electrode include platinum, platinum-clad titanium, gold, nickel, iridium oxide, ruthenium oxide, titanium, graphite, and palladium. The working electrode chamber and the counter electrode chamber are separated, for example, by an ion exchange membrane. This allows for more efficient reduction of heavy metal ions. The ion exchange membrane may be a cation exchange membrane, an anion exchange membrane, or a combination of both. The ion exchange membrane can be appropriately selected from commercially available ion exchange membranes. From the viewpoint of heavy metal ion reduction efficiency, the ion exchange membrane may include at least a cation exchange membrane. For example, the cation exchange membrane may include a copolymer of fluororesin based on sulfonated tetrafluoroethylene. Alternatively, instead of an ion exchange membrane, a membrane that does not easily permeate heavy metal ions, such as a reverse osmosis membrane (RO membrane) or a nanofiltration membrane (NF membrane, loose RO membrane), may be used.

[0041] When an aqueous solution containing conductive ions is placed in the counter electrode chamber, the aqueous solution may contain at least water and conductive ions. The conductive ions may be derived from water-soluble metal salts or from water-soluble acidic compounds (acidic components). Examples of conductive ions include cations such as hydrogen ions, alkali metal ions, alkaline earth metal ions, and ammonium ions; and anions such as sulfate ions, nitrate ions, phosphate ions, halogen ions, alkyl sulfonate ions, alkanol sulfonate ions, aromatic sulfonate ions, alkyl carboxylate ions, and aromatic carboxylate ions. Here, the number of carbon atoms in the alkyl group constituting the anion may be, for example, 1 to 6, preferably 1 to 3. The aromatic group may be an aryl group or a heteroaryl group, and the number of carbon atoms in the aromatic group may be, for example, 4 to 10, preferably 6. Examples of heteroatoms in the heteroaryl group include nitrogen atoms, oxygen atoms, and sulfur atoms. The alkyl group and aromatic group may have at least one substituent, and examples of substituents include halogen atoms, aliphatic groups having 1 to 3 carbon atoms, and alkoxy groups having 1 to 3 carbon atoms.

[0042] The current density in the electrolysis treatment of heavy metal ions should be appropriately selected depending on the type of heavy metal ion. For example, the current density should be 0.05 A / dm². ２ 10A / dm or more ２ The following may be true, preferably 0.1 A / dm ２ Above or above, or 7 A / dm ２ The following may apply: The temperature during the electrolysis process may be, for example, 20°C to 80°C, preferably 35°C to or 75°C to or from. The time required for the electrolysis process may be, for example, 10 minutes to 200 hours.

[0043] In the fourth step, the fourth solution is subjected to electrodialysis to separate it into a sixth solution from which at least a portion of alkali metal ions and the like have been removed, and a seventh solution containing the removed alkali metal ions and the like. The electrodialysis can be performed, for example, by an electrodialysis apparatus equipped with at least one of a cation exchange membrane and an anion exchange membrane. By subjecting the fourth solution, which contains alkali metal ions and the like and anions derived from acidic compounds, to electrodialysis to remove at least a portion of the alkali metal ions and the like, and separating it into an acidic sixth solution containing anions derived from acidic compounds and an alkaline seventh solution containing alkali metal ions and the like, the fourth solution produced in the regeneration process of the second adsorbent material can be reused in the adsorbent material treatment method without being discharged as waste liquid.

[0044] Electrodialysis is a membrane separation method that utilizes electricity and at least one ion exchange membrane, such as a cation exchange membrane and an anion exchange membrane, to separate and concentrate ionic components dissolved in water. An electrodialysis apparatus may be configured, for example, with at least one ion exchange membrane, such as a cation exchange membrane and an anion exchange membrane, positioned as a diaphragm between two electrodes. When the diaphragm is a cation exchange membrane, applying a voltage between the two electrodes causes cations to permeate the cation exchange membrane and move to the cathode side. This separates a fourth solution containing alkali metal ions and anions from a sixth solution containing anions and hydrogen ions after the alkali metal ions are removed, and a seventh solution containing cations (e.g., alkali metal ions) and hydroxide ions. The material of the electrodes in the electrodialysis apparatus is the same as the material of the counter electrodes in the electrochemical apparatus described above.

[0045] Furthermore, the electrodialysis apparatus may be configured such that, for example, cation exchange membranes and anion exchange membranes are alternately arranged as a diaphragm between two electrodes. When a voltage is applied between the two electrodes, cations move to the cathode side through the cation exchange membrane, and anions move to the anode side through the anion exchange membrane. As a result, the fourth solution containing alkali metal ions and anions can be separated into a sixth solution containing anions and hydrogen ions after the alkali metal ions have been removed, and a seventh solution containing cations (for example, alkali metal ions) and hydroxide ions.

[0046] An electrodialysis apparatus may be equipped with a bipolar membrane as an ion exchange membrane. By using an electrodialysis apparatus equipped with a bipolar membrane, the fourth solution can be separated more efficiently into the sixth and seventh solutions. A bipolar membrane is an ion exchange membrane having a structure in which an anion exchange membrane and a cation exchange membrane are bonded together. By applying a voltage to both sides of the bipolar membrane, the water inside the membrane decomposes to produce hydrogen ions and hydroxide ions. An electrodialysis apparatus equipped with a bipolar membrane may further be equipped with at least one of a cation exchange membrane and an anion exchange membrane in addition to the bipolar membrane.

[0047] An example of an electrodialysis apparatus equipped with a cation exchange membrane as a diaphragm will be explained using a schematic diagram. In Figure 1, sodium ions are shown as cations and carboxylate ions as anions, but the cations and anions are not limited to these. The electrodialysis apparatus 100 shown in Figure 1 is configured with a cation exchange membrane 34 placed between the anode 10 and the cathode 20, and is divided into two chambers, an anode chamber 2 and a cathode chamber 4. When a voltage is applied between the anode 10 and the cathode 20, cations 52 present in the anode chamber 2 move through the cation exchange membrane 34 to the cathode chamber 4. Anions 54 cannot pass through the cation exchange membrane 34 and remain in chamber A 42. In addition, water is decomposed at the anode 10 and cathode 20 to produce hydrogen ions 62 and hydroxide ions 64, which compensate for the charge transfer associated with the movement of cations 52. As a result, in the anode chamber 2, a sixth solution is produced in which the cations 52 are removed and the anions are separated and concentrated, and in the cathode chamber 4, a seventh solution is produced in which the cations 52 are separated and concentrated. The electrodialysis apparatus in Figure 1 is equipped with a cation exchange membrane, but an anion exchange membrane may be provided instead of a cation exchange membrane.

[0048] An example of an electrodialysis apparatus equipped with bipolar membranes will be explained using a schematic diagram. In Figure 2, sodium ions are used as cations and carboxylate ions as anions, but the cations and anions are not limited to these. The electrodialysis apparatus 200 shown in Figure 2 is configured by alternately arranging three bipolar membranes 32 and two cation exchange membranes 34 between the anode 10 and the cathode 20, and is divided into four chambers: chamber A 42, chamber B 44, chamber C 46 and chamber D 48. When a voltage is applied between the anode 10 and the cathode 20, cations 52 present in chamber A 42 permeate the cation exchange membrane 34 and move to chamber B 44 on the cathode 20 side. Anions 54 cannot permeate the cation exchange membrane 34 and remain in chamber A 42. Similarly, cations 52 present in chamber C 46 permeate the cation exchange membrane 34 and move to chamber D 48 on the cathode 20 side. Anions 54 cannot pass through the cation exchange membrane 34 and remain in chamber C 46. In addition, water is decomposed in the bipolar membrane 32 to produce hydrogen ions 62 and hydroxide ions 64, which compensate for the charge transfer associated with the movement of cations 52. As a result, a sixth solution is produced in chambers A 42 and C 46, in which cations 52 are removed and anions are separated and concentrated, while a seventh solution is produced in chambers B 44 and D 48, in which cations 52 are separated and concentrated.

[0049] Furthermore, the seventh solution, from which the cation 52 has been separated and concentrated, can be reused in the next electrodialysis treatment. For example, the seventh solution can be diluted by adding pure water while stirring, so that its concentration is equivalent to that before electrodialysis. As a method for adjusting the solution concentration, for example, the conductivity of the solution can be measured and adjusted so that its conductivity is equivalent to that of the solution before electrodialysis. By performing this treatment, the volume of the seventh solution increases compared to before electrodialysis. When the increased volume is removed from the electrodialysis machine, the same volume of solution as before electrodialysis remains in chambers B 44 and D 48, and this can be used in the next electrodialysis treatment. In addition, the removed seventh solution can be reused as at least a part of the first solution, as described above. By performing such treatment, it is possible to continue operating the electrodialysis machine without the need to add new drugs or generate waste liquid.

[0050] The electrodialysis apparatus in Figure 2 is equipped with a cation exchange membrane in addition to a bipolar membrane, but an anion exchange membrane may be provided instead of the cation exchange membrane.

[0051] The current density in the electrodialysis treatment of the fourth solution is, for example, 1 A / dm². ２ 20A / dm or more ２ The following may be true, preferably 2 A / dm ２ Above or above, or 10 A / dm ２ The following may apply: The temperature during the electrodialysis treatment may be, for example, 20°C to 80°C, preferably 30°C to or 40°C to or from. The time required for the electrodialysis treatment may be, for example, 10 minutes to 200 hours.

[0052] The invention relating to this disclosure may encompass, for example, the following embodiments: [1] A method for processing an adsorbent material comprising at least one selected from the group consisting of ion exchange resins and chelate resins, comprising: contacting a first adsorbent material on which heavy metal ions are adsorbed with a first solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions and having a pH greater than 7, thereby obtaining a second adsorbent material on which at least a portion of the heavy metal ions are desorbed and at least one selected from the group consisting of alkali metal ions and ammonium ions is attached, and a second solution containing the heavy metal ions; and contacting the second adsorbent material with a third solution having a pH less than 7, thereby obtaining a third adsorbent material on which at least a portion of the at least one selected from the group consisting of alkali metal ions and ammonium ions is removed. A method for processing an adsorbent material, comprising: obtaining a material and a fourth solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions; electrolyzing the second solution to reduce at least a portion of the heavy metal ions to metal to obtain a fifth solution from which at least a portion of the heavy metal ions has been removed; and electrodialysis the fourth solution using an electrodialysis apparatus equipped with at least one ion exchange membrane of a cation exchange membrane and an anion exchange membrane to obtain a sixth solution from which at least a portion of at least one selected from the group consisting of alkali metal ions and ammonium ions has been removed, and a seventh solution containing at least one selected from the group consisting of the removed alkali metal ions and ammonium ions.

[0053] [2] The treatment method according to [1], wherein the adsorbent material comprises at least a chelate resin having an aminophosphate group.

[0054] [3] The treatment method according to [1] or [2], wherein the heavy metal ion includes tin ions.

[0055] [4] The electrodialysis apparatus comprises a bipolar membrane as an ion exchange membrane. The processing method according to any one of [1] to [3].

[0056] [5] The treatment method according to any one of [1] to [4], wherein the pH of the first solution is 9 or more and 14 or less, and the pH of the third solution is 0 or more and 5 or less.

[0057] [6] The treatment method according to any one of [1] to [5], wherein the first solution has a total concentration of alkali metal ions and ammonium ions of 0.04 mol / L or more and 2 mol / L or less, and a pH of 12.6 or more and 14 or less.

[0058] [7] The treatment method according to any one of [1] to [6], wherein the heavy metal ion content of the second solution is 90 mol% or more of the heavy metal ions adsorbed on the first adsorbent material.

[0059] [8] The processing method according to any one of [1] to [7], comprising reusing at least a portion of the fifth solution as at least a portion of the first solution.

[0060] [9] The processing method according to any one of [1] to [8], comprising reusing at least a portion of the seventh solution as at least a portion of the first solution.

[0061]

[10] The processing method according to any one of [1] to [9], comprising reusing at least a portion of the sixth solution as at least a portion of the third solution.

[0062] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0063] Example 1 1. Preparation of the first adsorbent material 40 ml of chelate resin XMS-5416 (Muromachi Chemical) was measured using a graduated cylinder and packed into a column (Organo amber column). An aqueous solution containing 0.08 mol / L of potassium stin(IV)ate and 0.40 mol / L of sodium gluconate was prepared and used as simulated tin waste liquid. A beaker containing 200 ml of simulated tin waste liquid was connected to the column with a resin tube, and the liquid was circulated using a tube pump at a flow rate of 30 ml / min for 3 hours. After the liquid circulation, 200 ml of pure water was passed through the column at a flow rate of 3.3 ml / min to wash the chelate resin. The chelate resin from which tin ions were adsorbed in this manner was used as the first adsorbent material.

[0064] 2. Preparation of the first solution: 240 ml of a 0.4 mol / L sodium hydroxide aqueous solution was prepared and used as the first solution.

[0065] 3. Process to obtain the second adsorbent and second solution A beaker containing the first solution and a column packed with the first adsorbent were connected with a resin tube, and the liquid was circulated for 1 hour at a flow rate of 30 ml / min using a tube pump. After the liquid circulation, 200 ml of pure water was passed through the column at a flow rate of 3.3 ml / min to wash the chelate resin. The washed chelate resin was used as the second adsorbent. In addition, a mixture of the alkaline solution after circulation and the washing waste liquid after passing through the column was heated to 80°C to evaporate the water and reduced in volume to 240 ml to obtain the second solution.

[0066] 4. Preparation of the third solution: 240 ml of an aqueous solution of methanesulfonic acid containing 0.4 mol / L of methanesulfonic acid was prepared and used as the third solution.

[0067] 5. Process to obtain the third adsorbent and the fourth solution A column containing the second adsorbent and a beaker containing 240 ml of the third solution were connected with a resin tube, and the liquid was circulated for 1 hour at a flow rate of 30 ml / min using a tube pump. After the liquid circulation, 200 ml of pure water was passed through the column at a flow rate of 3.3 ml / min to wash the chelate resin. The washed chelate resin was used as the third adsorbent. The methanesulfonic acid-containing solution after circulation and the washing waste liquid after passing through the column were mixed, and the mixture was heated to 80°C to evaporate the water, reducing the volume to 240 ml to obtain the fourth solution.

[0068] 6. Process to obtain the fifth solution (electrolysis) An acrylic container with internal dimensions of 68 mm x 90 mm x 50 mm (internal volume approximately 300 ml) was set up as an electrochemical apparatus by placing a Pt-coated Ti mesh (67 mm x 100 mm x 2 mm) as the anode and a copper plate (67 mm x 100 mm x 0.3 mm) as the cathode. 240 ml of the second solution obtained above was added to the electrochemical apparatus, and electrolysis was performed for 15 hours at a current of 0.26 A while heating the acrylic container to 60°C in a water bath. The solution after electrolysis was designated as the fifth solution. Metallic tin was deposited on the cathode.

[0069] 7. Process to obtain the sixth and seventh solutions (electrodialysis) An electrodialysis apparatus was prepared, as shown in Figure 3, having two chambers, an anode chamber and a cathode chamber, separated by a cation exchange membrane (CMB manufactured by Astom Co., Ltd.), with Pt-coated Ti mesh installed in both the anode and cathode chambers. The effective area of ​​the cation exchange membrane was 26.5 cm². ２ The dimensions were (68 mm x 39 mm). 240 ml of the fourth solution was placed in the anode chamber, and 240 ml of a 2.0 mol / L sodium hydroxide solution was placed in the cathode chamber. 2.1 A (current density 8 A / dm²) was applied to this electrodialysis apparatus. ２ Electrodialysis was performed by applying the current from the ) for 8 hours. The solution in the anode chamber after treatment was designated as solution 6, and the solution in the cathode chamber was designated as solution 7.

[0070] 8. Mixing of Solution 5 and Solution 7: 40 ml of Solution 7 (sodium hydroxide solution) was added to 240 ml of Solution 5 while stirring to prepare Solution 8.

[0071] 9. Solution Reuse Solution No. 8 was used as the first solution and solution No. 6 as the third solution, and the same process as in "1. Preparation of the First Adsorbent Material", "3. Steps to Obtain the Second Adsorbent Material and Second Solution", and "5. Steps to Obtain the Third Adsorbent Material and Fourth Solution" was carried out. The column containing the third adsorbent material obtained in this way was connected to a beaker containing 100 ml of simulated tin waste liquid with a resin tube, and the liquid was circulated for 1 hour at a flow rate of 30 ml / min using a tube pump. The solution after circulation was collected, and the tin ion collection efficiency was calculated as follows. The results are shown in Table 1.

[0072] Tin ion collection amount [g] = (Tin ion concentration of simulated tin waste liquid before circulation [g / L] × Volume of simulated tin waste liquid before circulation [L]) - (Tin ion concentration of recovered liquid after circulation [g / L] × Volume of recovered liquid [L]) Tin ion collection rate (%) = Tin ion collection amount [g] / (Tin ion concentration of simulated tin waste liquid before circulation [g / L] × Volume of simulated tin waste liquid before circulation [L]) × 100

[0073] Reference Example 1 In "9. Solution Reuse" of Example 1, instead of regenerating and reusing the solution used to treat the adsorbent material, a newly prepared solution was used to treat the adsorbent material. A newly prepared 0.4 mol / L sodium hydroxide aqueous solution was used as the first solution, and a newly prepared 0.4 mol / L methanesulfonic acid aqueous solution was used as the third solution. The same procedures as in "1. Preparation of the First Adsorbent Material," "3. Step to Obtain the Second Adsorbent Material and Second Solution," and "5. Step to Obtain the Third Adsorbent Material and Fourth Solution" were performed, and the tin ion collection efficiency was calculated in the same manner as in Example 1. The results are shown in Table 1.

[0074] Comparative Example 1 The tin ion collection efficiency was calculated in the same manner as in Example 1, except that steps "6. Step to obtain the fifth solution (electrolysis)," "7. Step to obtain the sixth and seventh solutions (electrodialysis)," and "8. Mixing of the fifth and seventh solutions" were not performed, and in "9. Solution reuse," the second solution was used as the first solution instead of the eighth solution, and the fourth solution was used as the third solution instead of the sixth solution. The results are shown in Table 1.

[0075]

[0076] When the adsorbent material was treated with a solution that had been regenerated using a predetermined method, the tin ion collection rate was 88%, indicating that the adsorbent material could be reused. Furthermore, since the second and fourth solutions used in the first treatment were regenerated and reused, the solutions could be recycled. Next, when the adsorbent material was treated with a newly prepared solution (Reference Example 1), although the tin ion collection rate was high, the solutions could not be recycled, and a large amount of chemicals were consumed. On the other hand, when the adsorbent material was treated again without treating it with the second and fourth solutions (Comparative Example 1), the tin ion collection rate was low, and the adsorbent material could not be sufficiently reused.

[0077] In Example 2, the second and fourth solutions obtained by carrying out "9. Solution Reuse" were subjected to solution regeneration treatments in "6. Step to obtain the fifth solution (electrolysis)", "7. Step to obtain the sixth and seventh solutions (electrodialysis)", and "8. Mixing of the fifth and seventh solutions" to obtain the sixth and eighth solutions. When the obtained sixth and eighth solutions were used to carry out "9. Solution Reuse" again, a good tin ion collection rate was observed.

[0078] The results of Example 2 show that the solution can be regenerated and reused repeatedly. Furthermore, it was confirmed that the solution can be reused approximately 50 to 100 times through the solution regeneration process. At this time, the tin ion concentration in the eighth solution before use in "3. Step to obtain the second adsorbent material and second solution" was maintained at 0.08 mol / L or less, and the sodium ion concentration in the sixth solution before use in "5. Step to obtain the third adsorbent material and fourth solution" was maintained at 0.2 mol / L or less. Therefore, it can be said that solution regeneration and reuse are effective methods for the recycling of the solution in the regeneration process of the adsorbent material.

[0079] In Example 1, the solution was reused, including the wash water after passing pure water through the column to wash the chelate resin. However, it was also possible to reuse only the treated solution without including the wash water. In this case, although the components contained in the wash water could not be reused, the solution would not be diluted by the wash water, making it possible to omit the concentration process.

[0080] Furthermore, while Example 1 uses a method of heating to 80°C and evaporating as the concentration method, it is also possible to apply methods such as concentration using a reverse osmosis (RO) membrane apparatus or concentration using a vacuum distillation apparatus, and by using these apparatuses, it is possible to reduce the processing costs associated with the concentration process.

[0081] The disclosure of Japanese Patent Application No. 2025-026838 (filing date: February 21, 2025) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A method for processing an adsorbent material comprising at least one selected from the group consisting of ion exchange resins and chelate resins, comprising: contacting a first adsorbent material on which heavy metal ions are adsorbed with a first solution having a pH greater than 7 and containing at least one selected from the group consisting of alkali metal ions and ammonium ions to obtain a second adsorbent material on which at least a portion of the heavy metal ions are desorbed and at least one selected from the group consisting of alkali metal ions and ammonium ions is attached, and a second solution containing the heavy metal ions; contacting the second adsorbent material with a third solution having a pH less than 7 to obtain a third adsorbent material from which at least a portion of the at least one selected from the group consisting of alkali metal ions and ammonium ions has been removed, and a fourth solution containing at least one selected from the group consisting of alkali metal ions and ammonium ions; and electrolyzing the second solution to reduce at least a portion of the heavy metal ions to metal to obtain a fifth solution from which at least a portion of the heavy metal ions have been removed. A method for treating an adsorbent material, comprising: electrodialysis of the fourth solution using an electrodialysis apparatus equipped with at least one ion exchange membrane, a cation exchange membrane and an anion exchange membrane, to obtain a sixth solution from which at least a portion of at least one selected from the group consisting of alkali metal ions and ammonium ions has been removed; and a seventh solution containing at least one selected from the group consisting of the removed alkali metal ions and ammonium ions.

2. The treatment method according to claim 1, wherein the adsorbent material comprises at least a chelate resin having an aminophosphate group.

3. The treatment method according to claim 1 or 2, wherein the heavy metal ions include tin ions.

4. The processing method according to any one of claims 1 to 3, wherein the electrodialysis apparatus comprises a bipolar membrane as an ion exchange membrane.

5. The processing method according to any one of claims 1 to 4, wherein the pH of the first solution is 9 or more and 14 or less, and the pH of the third solution is 0 or more and 5 or less.

6. The treatment method according to any one of claims 1 to 5, wherein the first solution has a total concentration of alkali metal ions and ammonium ions of 0.04 mol / L or more and 2 mol / L or less, and a pH of 12 or more and 14 or less.

7. The treatment method according to any one of claims 1 to 6, wherein the heavy metal ion content of the second solution is 90 mol% or more of the heavy metal ions adsorbed on the first adsorbent material.

8. The processing method according to any one of claims 1 to 7, comprising reusing at least a portion of the fifth solution as at least a portion of the first solution.

9. The processing method according to any one of claims 1 to 8, comprising reusing at least a portion of the seventh solution as at least a portion of the first solution.

10. The processing method according to any one of claims 1 to 9, comprising reusing at least a portion of the sixth solution as at least a portion of the third solution.

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