Method using adsorbent material

Abstract

The object of this invention is to provide a novel method for recovering metals and / or metal ions from a treatment liquid using a single adsorbent material, and a novel method for regenerating the adsorbent material used in the method for recovering metals and / or metal ions from the treatment liquid. To achieve this object, a method for recovering metals and / or metal ions is provided, comprising the following steps: (1) preparing a solution containing metals and / or metal ions; (2) preparing an adsorbent material having a co-continuous structure formed by a ceramic framework containing mesopores and macropores. The surface of the framework is modified with functional groups capable of adsorbing metals and / or metal ions, the modal pore size of the macropores before modification with the aforementioned functional groups is 0.20 μm or more and 4.0 μm or less, and the modal pore size of the mesopores before modification with the aforementioned functional groups is 2.0 nm or more and 50 nm or less; (3) a step of contacting the aforementioned solution with the aforementioned adsorbent material; (4) a step of contacting the aforementioned adsorbent material supplied in step (3) with an acidic solution; and (5) a step of recovering the aforementioned metals and / or the aforementioned metal ions from the acidic solution supplied in step (4).

Description

Technical Field

[0001] This invention relates to methods using adsorbent materials. Background Technology

[0002] Methods for recovering metals and / or metal ions from a target liquid using monolithic adsorbent materials are known. For example, as described in Patent Document 1, monolithic adsorbent materials have historically been in the form of fine granules.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2017 / 002871 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The object of this invention is to provide a novel method for recovering metals and / or metal ions from a treatment liquid using a single piece of adsorbent material, and a novel method for regenerating the adsorbent material used in the method for recovering metals and / or metal ions from a treatment liquid.

[0008] Solution for solving the problem

[0009] To address the aforementioned issues, the present invention provides the following method.

[0010] [A] A method for recovering metals and / or metal ions, comprising the following steps:

[0011] (1) The process of preparing a solution containing metals and / or metal ions;

[0012] (2) The step of preparing an adsorbent material, wherein the adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, the surface of the aforementioned ceramic framework is modified by functional groups capable of adsorbing metals and / or metal ions, the modal pore size of the aforementioned macropores before modification with the aforementioned functional groups is 0.20 μm or more and 4.0 μm or less, and the modal pore size of the aforementioned mesopores before modification with the aforementioned functional groups is 2.0 nm or more and 50 nm or less.

[0013] (3) The process of bringing the aforementioned solution into contact with the aforementioned adsorbent material;

[0014] (4) The process of contacting the aforementioned adsorbent material supplied to step (3) with the acidic solution; and

[0015] (5) A process for recovering the aforementioned metal and / or the aforementioned metal ions from the acidic solution supplied to process (4).

[0016] [B] A method for regenerating the adsorbent material used in the method described in [A], comprising a step of contacting the aforementioned adsorbent material supplied to step (4) with an alkaline solution.

[0017] The effects of the invention

[0018] According to the present invention, novel methods for recovering metals and / or metal ions from a treatment liquid using a single piece of adsorbent material, and novel methods for regenerating the adsorbent material used in the method for recovering metals and / or metal ions from a treatment liquid are provided. Attached Figure Description

[0019] Figure 1 This is a side view of the columnar body according to one embodiment of the present invention.

[0020] Figure 2A This is a cross-sectional view illustrating a method for calculating the average diameter of a columnar body according to one embodiment of the present invention.

[0021] Figure 2B This is a cross-sectional view illustrating a method for calculating the average diameter of a columnar body according to one embodiment of the present invention.

[0022] Figure 3 This is a partial enlarged view of the surface of the adsorbent material according to one embodiment of the present invention.

[0023] Figure 4A The SEM image was obtained to observe the surface structure of the silica monoparticles obtained in Manufacturing Example 1 using a scanning electron microscope (SEM).

[0024] Figure 4B SEM images (magnification ratio) obtained for observing the surface structure of the silica monoparticles obtained in Manufacturing Example 1 using a scanning electron microscope (SEM). Figure 4A high).

[0025] Figure 5 The SEM image was obtained to observe the surface structure of the silica monolithic adsorbent material obtained in Manufacturing Example 14 using a scanning electron microscope (SEM).

[0026] Figure 6 This is a schematic diagram of the flow adsorption device used in Experiment Example 4. Detailed Implementation

[0027] The First Method

[0028] The first method of the present invention is a method for recovering metals and / or metal ions, which includes the following steps:

[0029] (1) The process of preparing a solution containing metals and / or metal ions;

[0030] (2) The step of preparing an adsorbent material, wherein the adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, the surface of the aforementioned ceramic framework is modified by functional groups capable of adsorbing metals and / or metal ions, the mode pore size of the macropores before modification with the aforementioned functional groups is 0.20 μm or more and 4.0 μm or less, and the mode pore size of the mesopores before modification with the aforementioned functional groups is 2.0 nm or more and 50 nm or less.

[0031] (3) A process of bringing the solution prepared in step (1) into contact with the adsorbent material prepared in step (2);

[0032] (4) The process of contacting the adsorbent material supplied to process (3) with the acidic solution; and

[0033] (5) A process for recovering metals and / or metal ions from the acidic solution supplied to process (4).

[0034] The following is a description of each process.

[0035] Process (1)

[0036] In step (1), a solution containing metal and / or metal ions is prepared (hereinafter referred to as "the treatment solution").

[0037] Examples of liquids to be treated include wastewater discharged from factories and wastewater containing valuable metals discharged during metal refining processes. The liquids to be treated typically contain water. Wastewater can be used in process (3) after pretreatment, as needed.

[0038] There are no limitations on the metals and / or metal ions contained in the liquid to be treated, as long as they can be adsorbed by the adsorbent material prepared in step (2). Details regarding metals and metal ions are described below.

[0039] Process (2)

[0040] In step (2), an adsorbent material for adsorbing metals and / or metal ions is prepared. Specifically, an adsorbent material is prepared having a co-continuous structure formed by a ceramic framework containing mesopores and macropores. The surface of the ceramic framework is modified with functional groups capable of adsorbing metals and / or metal ions. The modal pore size of the macropores before modification with the aforementioned functional groups is 0.20 μm or more and 4.0 μm or less, and the modal pore size of the mesopores before modification with the aforementioned functional groups is 2.0 nm or more and 50 nm or less. This adsorbent material is particularly useful for recovering metals and / or metal ions from a treatment liquid with a low concentration of metals and / or metal ions (for example, a concentration of metals and / or metal ions of 0.2 ppm or more and 300 ppm or less, especially 0.2 ppm or more and 200 ppm or less). The adsorbent material will be described below.

[0041] <Morphology and Shape of Adsorbent Materials>

[0042] There are no particular limitations on the morphology of adsorbent materials. Examples of adsorbent material forms include particles, blocks, and shaped bodies. Furthermore, there are no particular limitations on the shape of adsorbent materials. Examples of adsorbent material shapes include columnar, spherical (e.g., perfect spheres, ellipsoids, etc.), needle-like, scaly (thin sheet-like), polyhedral, flat, fragmented, and blocky forms.

[0043] The preferred shape of the adsorbent material is columnar.

[0044] The following is for reference Figure 1 , 2A Sections 2B and 2B will be described with respect to a columnar body 1 according to one embodiment of the present invention.

[0045] like Figure 1 As shown, the columnar body 1 has an axial direction X. The axial direction X is aligned with the extending direction of the columnar body 1. Furthermore, as... Figure 1 As shown, the columnar body 1 has a first end face S1 located on one side of the axial direction X, a second end face S2 located on the other side of the axial direction X, and a side face S3 located between the first end face S1 and the second end face S2.

[0046] Figure 1 The first end face S1 and the second end face S2 shown are both planar, but one or both of the first end face S1 and the second end face S2 can be bent. Furthermore, Figure 1 The side surface S3 shown is a plane, but it can be bent.

[0047] The columnar body 1 can be, for example, cylindrical, elliptical, square, hexagonal, octagonal, or other polygonal shapes. Cylindrical, elliptical, square, hexagonal, and octagonal shapes respectively refer to the shape of the cross-section when the columnar body 1 is cut with a plane perpendicular to the axis X, resulting in a circular, elliptical, quadrilateral, hexagonal, or octagonal shape. The columnar body 1 can also be a partially missing shape, such as a cylindrical, elliptical, or polygonal shape; in this case, the cross-section of the columnar body 1 becomes a partially missing shape, such as a circle, ellipse, or polygon.

[0048] For example, as described in International Publication No. 2017 / 002871, the shape of existing monolithic adsorbent materials has always been fine granules. When granular monolithic adsorbent materials are packed into a column and used, the back pressure of the column tends to increase and the flow rate of the target liquid tends to decrease when the target liquid is introduced. Therefore, when the target liquid is in large quantities, it is difficult to accelerate the recovery rate of metals and / or metal ions from the target liquid. To prevent the back pressure from increasing and the flow rate of the target liquid from decreasing when packed into the column, one solution is to consider making the monolithic adsorbent material into a column shape instead of granules. The inventors have discovered that when the monolithic adsorbent material is made into a column shape, the size of the column can improve durability, making it less prone to damage even with repeated liquid flow. Hereinafter, the preferred column size from the viewpoint of balancing adsorption performance and durability will be described. Adsorbent materials that combine adsorption performance and durability are particularly useful when repeatedly regenerated for adsorbing metals and / or metal ions. Adsorbent materials that combine adsorption performance and durability can still exhibit excellent adsorption performance even after repeated regeneration and use.

[0049] From the viewpoint of improving durability, the average diameter of the columnar body 1 is preferably 1.5 mm or more, more preferably 2.5 mm or more, further preferably 3.0 mm or more, even more preferably 3.5 mm or more, and still more preferably 4.0 mm or more. On the other hand, from the viewpoint of improving adsorption performance, the average diameter of the columnar body 1 is preferably 20 mm or less, more preferably 14 mm or less, further preferably 12 mm or less, even more preferably 10 mm or less, and still more preferably 8.0 mm or less. These upper limits can be combined with any of the lower limits mentioned above.

[0050] The method for calculating the average diameter of columnar body 1 is shown below. Figure 1As shown, three arbitrary parts Q1, Q2, and Q3 of columnar body 1 (for example, Q1 is an arbitrary part of the upper part of columnar body 1, Q2 is an arbitrary part of the central part of columnar body 1, and Q3 is an arbitrary part of the lower part of columnar body 1) are cut by planes P1, P2, and P3 perpendicular to the axis X, respectively. The diameters of the three cross-sections C1, C2, and C3 are calculated, and their arithmetic mean is taken as the average diameter of columnar body 1. At this time, as... Figure 2A As shown, when the cross-section C1 is circular, the diameter D1 of the cross-section C1 is set as the diameter of the cross-section C1, such as... Figure 2B As shown, when the cross-section C1 is a shape other than a circle (e.g., an ellipse, quadrilateral, hexagon, octagon, or other polygon), the diameter D1' of the circle circumscribed in cross-section C1 is taken as the diameter of cross-section C1. The calculation methods for the diameters of cross-sections C2 and C3 are the same as those for the diameter of cross-section C1. It should be noted that... Figure 2B The cross-section C1 shown is a quadrilateral, which is an example of a cross-section C1 that is a shape other than a circle. The cross-section C1 can be any shape other than a quadrilateral.

[0051] like Figure 1 As shown, columnar body 1 has a length L. The length is a dimension equal to the axial direction X.

[0052] The length of columnar body 1 is calculated as follows. Figure 1 As shown, the length L of the quadrilateral T, which is circumscribed in the side view shape of the column 1, is defined as the length of the column 1. The length of the column 1 is not particularly limited, and from the point of view of convenience in practical application, it can be set to be more than 1 mm and less than 500 mm.

[0053] From the viewpoint of improving durability, the aspect ratio of the column 1 is preferably 0.70 or more, more preferably 1.0 or more, and even more preferably 1.5 or more. Furthermore, from the viewpoint of workability when filling and using the column, etc., and from the viewpoint of preventing a decrease in durability that may occur when the aspect ratio of the column 1 is too large, the aspect ratio of the column 1 is preferably 10 or less, more preferably 7.0 or less, even more preferably 5.0 or less, and even more preferably 4.0 or less. These upper limits can be combined with any of the lower limits mentioned above.

[0054] The aspect ratio of column 1 is determined using the following formula.

[0055] The aspect ratio of column 1 = length L of column 1 / average diameter of column 1.

[0056] <Structure of the adsorbent material before modification>

[0057] The following is for reference Figure 3The structure of the adsorbent material before modification with functional groups capable of adsorbing metals and / or metal ions is described. Figure 3 This is a partially enlarged view of the surface of the adsorbent material according to one embodiment of the present invention. The adsorbent material is... Figure 1 When the columnar body 1 is shown, Figure 3 Corresponding to Figure 1 A magnified view of region R in the image.

[0058] like Figure 3 As shown, the adsorbent material has a co-continuous structure formed by a ceramic framework 2 containing mesopores 4 and macropores 3.

[0059] In the adsorbent material, the ceramic framework 2 and the macropores 3 each possess a continuous three-dimensional network structure and are intertwined with each other, thus forming a co-continuous structure of the ceramic framework 2 and the macropores 3. The co-continuous structure of the ceramic framework 2 and the macropores 3 in the adsorbent material can be confirmed by observing the surface or cross-section of the adsorbent material using a scanning electron microscope (SEM).

[0060] From the viewpoint of improving adsorption performance, the mode pore size of the macropore 3 is preferably 0.20 μm or more, more preferably 0.50 μm or more, and even more preferably 0.80 μm or more. Furthermore, from the same viewpoint, the mode pore size of the macropore 3 is preferably 4.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. These upper limits can be combined with any of the lower limits mentioned above.

[0061] "The mode pore size of macropore 3" as described in the following embodiments refers to the mode pore size of the macropore measured by mercury intrusion porosimetry in the range of 50 nm to 500 μm.

[0062] From the viewpoint of improving adsorption performance, the mode pore size of the mesopore 4 is preferably 2.0 nm or more, more preferably 5.0 nm or more, and even more preferably 10 nm or more. Furthermore, from the same viewpoint, the mode pore size of the mesopore 4 is 50 nm or less, more preferably 30 nm or less, and even more preferably 25 nm or less. These upper limits can be combined with any of the lower limits mentioned above.

[0063] "The mode pore size of mesopore 4" as described in the examples described later refers to the mode pore size of the mesopore measured using the BJH method based on the nitrogen adsorption-desorption isotherm.

[0064] From the viewpoint of improving adsorption performance, the ratio of the mode pore size of the macropore 3 to the mode pore size of the mesopore 4 is preferably 15 or more, more preferably 20 or more, even more preferably 30 or more, and even more preferably 40 or more. Furthermore, from the same viewpoint, this ratio is preferably 200 or less, more preferably 150 or less, even more preferably 130 or less, and even more preferably 120 or less. These upper limits can be combined with any of the lower limits mentioned above.

[0065] From the perspective of improving adsorption performance, the specific surface area of ​​the adsorbent material, measured using the BET method based on the nitrogen adsorption-desorption isotherm, is preferably 100 m². 2 / g or more, more preferably 120m 2 / g or more, and more preferably 130m 2 / g or more. There is no particular upper limit to the specific surface area of ​​the adsorbent material. The method for determining the specific surface area based on the nitrogen adsorption-desorption isotherm and using the BET method is as described in the examples below.

[0066] From the viewpoint of improving adsorption performance, the total pore volume of the adsorbent material measured by mercury porosimetry is preferably 1.5 mL / g or more and 4.0 mL / g or less, more preferably 1.8 mL / g or more and 3.5 mL / g or less, and even more preferably 2.0 mL / g or more and 3.0 mL / g or less. The method for determining the total pore volume based on mercury porosimetry is as described in the examples described later.

[0067] From the viewpoint of improving adsorption performance, the porosity of the adsorbent material measured by mercury porosimetry is preferably 70% or more and 90% or less, more preferably 70% or more and 85% or less, and even more preferably 70% or more and 80% or less. The method for determining porosity based on mercury porosimetry is as described in the examples described later.

[0068] <Material of the Adsorbent Material>

[0069] The ceramics that form the ceramic framework are, for example, oxide ceramics containing semi-metallic or metallic elements.

[0070] Examples of silicon as a semi-metallic element include silicon dioxide (SiO2). Examples of silicon-containing oxide ceramics include silicon dioxide (SiO2).

[0071] Examples of metallic elements include aluminum, tin, cerium, titanium, zirconium, vanadium, chromium, iron, cobalt, nickel, palladium, platinum, copper, silver, gold, and zinc, among other transition metals. From the viewpoint of ease of manufacturing the adsorbent material, aluminum, tin, cerium, titanium, or zirconium are preferred. Examples of oxide ceramics containing aluminum, tin, cerium, titanium, or zirconium include aluminum oxide (Al₂O₃), tin oxide (SnO₂), cerium dioxide (CeO₂), titanium dioxide (TiO₂), and zirconium oxide (ZrO₂).

[0072] Oxide ceramics may contain silicon or transition metal elements, as well as elements selected from alkali metals such as lithium and sodium, alkaline earth metals such as magnesium and calcium, and rare earth elements such as lanthanum, scandium, yttrium, and gadolinium.

[0073] <Manufacturing Methods of Adsorbent Materials>

[0074] Adsorbent materials can be manufactured by methods including, for example, the following steps.

[0075] (a) A process for manufacturing polyoxometalate gels by sol-gel method;

[0076] (b) The process of forming pores in the framework of the polyoxometalate gel manufactured by process (a); and

[0077] (c) The process of cleaning and / or drying the polyoxometalate gel supplied to process (b) as needed, and then firing it to manufacture ceramic monoliths.

[0078] The following is a description of each process.

[0079] Process (a)

[0080] In step (a), polyoxometalate gel is manufactured by the sol-gel method.

[0081] Polymetalloxanes are inorganic polymers with metalloalkane bonds as their main chain backbone. Metalloalkane bonds are bonds between half-metal elements or metal elements and oxygen atoms, i.e., MO bonds (where M represents half-metal elements or metal elements).

[0082] Examples of half-metallic elements represented by M include silicon. Examples of metallic elements represented by M include transition metal elements such as aluminum, tin, cerium, titanium, zirconium, vanadium, chromium, iron, cobalt, nickel, palladium, platinum, copper, silver, gold, and zinc. From the viewpoint of ease of manufacturing the adsorbent material, aluminum, tin, cerium, titanium, or zirconium are preferred.

[0083] The sol-gel method can be performed using conventional methods. An example of the sol-gel method is shown below.

[0084] The sol-gel method includes a sol manufacturing process and a gel manufacturing process.

[0085] In the sol-gel manufacturing process, a reaction solution containing ceramic precursors, catalysts, and macropore-forming agents is stirred to produce a sol.

[0086] There are no particular limitations on ceramic precursors as long as they can form polyoxometalate gels.

[0087] Ceramic precursors may be, for example, half-metal compounds (e.g., silicon compounds) having hydroxyl groups and / or hydrolyzable functional groups, or metal compounds (e.g., aluminum compounds, tin compounds, cerium compounds, titanium compounds, zirconium compounds, etc.) having hydroxyl groups and / or hydrolyzable functional groups. The total number of hydroxyl groups and hydrolyzable functional groups in the ceramic precursor may be 1 or 2, but from the viewpoint of manufacturing polyoxometalate gels with a highly cross-linked structure based on metal-oxoalkane bonds (MO bonds), 3 or more is preferred, and 4 is more preferred. When the ceramic precursor has two or more types of hydrolyzable functional groups, the types of the two or more hydrolyzable functional groups may be the same or different.

[0088] The hydrolyzable functional group is a functional group that is converted into a hydroxyl group through hydrolysis. Examples of hydrolyzable functional groups include alkoxy, acetoxy, halide group, and hydride group, with alkoxy being preferred. The alkoxy group is preferably an alkoxy group with 1 to 10 carbon atoms, more preferably an alkoxy group with 1 to 5 carbon atoms, and even more preferably a methoxy, ethoxy, or propyl group. The alkoxy group can be linear or branched.

[0089] The ceramic precursor may have functional groups other than hydroxyl and hydrolyzable functional groups. Examples of functional groups other than hydroxyl and hydrolyzable functional groups include alkyl, alkenyl, phenyl, phenoxy, carboxyl, epoxy, aldehyde, thiol, amino, acryloyl, and methacryloyl. The alkyl group is preferably an alkyl group with 1 to 10 carbon atoms, more preferably an alkyl group with 1 to 5 carbon atoms, and even more preferably methyl, ethyl, or propyl. The alkyl group may be linear or branched. The alkenyl group is preferably an alkenyl group with 2 to 10 carbon atoms, more preferably an alkenyl group with 2 to 5 carbon atoms, and even more preferably vinyl. The alkenyl group may be linear or branched.

[0090] Silicon compounds having hydroxyl groups and / or hydrolyzable functional groups are preferably alkoxysilanes. Examples of alkoxysilanes include tetraalkoxysilanes, trialkoxysilanes, dialkoxysilanes, and monoalkoxysilanes; among these, tetraalkoxysilanes are preferred from the viewpoint of readily undergoing hydrolysis and polycondensation reactions. Examples of tetraalkoxysilanes include tetramethoxysilanes and tetraethoxysilanes.

[0091] Aluminum compounds having hydroxyl groups and / or hydrolyzable functional groups are preferably aluminum hydroxide, aluminum alkoxide, etc.

[0092] Tin compounds having hydroxyl and / or hydrolyzable functional groups are preferably tin hydroxide, tin alkoxide, etc.

[0093] Cerium compounds having hydroxyl groups and / or hydrolyzable functional groups are preferably cerium hydroxide, cerium alkanol, etc.

[0094] Titanium compounds having hydroxyl groups and / or hydrolyzable functional groups are preferably titanium alkoxides. Examples of titanium alkoxides include monoalkoxides, dialkoxides, trialkoxides, and tetraalkoxides; among these, tetraalkoxides are preferred from the viewpoint of readily undergoing hydrolysis and polycondensation reactions. Examples of tetraalkoxides include, for instance, tetraisopropoxides.

[0095] Zirconium compounds having hydroxyl groups and / or hydrolyzable functional groups are preferably alkanolate zirconium. Examples of alkanolate zirconium include monoalkanolate zirconium, dialkanolate zirconium, trialkanolate zirconium, and tetraalkanolate zirconium, among which tetraalkanolate zirconium is preferred from the viewpoint of readily undergoing hydrolysis and polycondensation reactions. Examples of tetraalkanolate zirconium include, for instance, tetraisopropoxide zirconium.

[0096] The ceramic precursor can be a metal salt (e.g., aluminum salt, tin salt, cerium salt, etc.) that is converted into hydroxide through hydrolysis. Examples of aluminum salts include aluminum nitrate, aluminum sulfate, and aluminum chloride. Examples of tin salts include tin nitrate, tin sulfate, and tin chloride. Examples of cerium salts include cerium nitrate, cerium sulfate, and cerium chloride. Among these, aluminum chloride, tin chloride, or cerium chloride is preferred from the viewpoint of readily undergoing hydrolysis and condensation reactions.

[0097] Catalysts function as catalysts in hydrolysis reactions. Examples of catalysts include acids and bases. Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; and organic acids such as formic acid, acetic acid, oxalic acid, and citric acid. Examples of bases include amines such as sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, and trimethylammonium hydroxide; ammonium hydroxides such as tert-butylammonium hydroxide; and alkali metal alkanols such as sodium methoxide.

[0098] Macropore-forming agents facilitate the formation of macropores in ceramic monoliths. Examples of macropore-forming agents include water-soluble polymers and surfactants, with water-soluble polymers being preferred. Water-soluble polymers induce sol-gel phase transitions accompanied by phase separation processes (typically spinodal decomposition), which helps to form a co-continuous structure of the framework and solvent phases in the gel, thereby contributing to the formation of macropores in the ceramic monoliths.

[0099] Examples of water-soluble polymers include polyethylene glycol, polypropylene glycol and other polyalkylene glycols; polyacrylic acid, polyethylene glycol-polypropylene glycol block copolymers, polyvinylpyrrolidone, sodium polystyrene sulfonate, polyallylamine hydrochloride, etc.

[0100] From the viewpoint of efficiently carrying out phase separation processes (typically Spinardo decomposition), the weight-average molecular weight of the water-soluble polymer is preferably 8,000 or more and 15,000 or less. The weight-average molecular weight is determined by GPC (gel permeation chromatography).

[0101] Examples of surfactants include cationic surfactants such as cetyltrimethylammonium chloride, anionic surfactants such as sodium dodecyl sulfate, and nonionic surfactants such as polyoxyethylene alkyl ethers.

[0102] When the ceramic precursor is a half-metallic compound, the reaction solution may contain a mesoporous forming agent. The mesoporous forming agent helps to form mesopores in the ceramic monolith. Examples of mesoporous forming agents include, for example, nitrogen compounds. Examples of nitrogen compounds that can be used as mesoporous forming agents include amide compounds such as urea, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, and N,N-dimethylacetamide; and heterocyclic compounds such as hexamethylenetetramine. Among these, urea is preferred from the viewpoint of effectively forming mesopores.

[0103] The reaction solution may contain one or more solvents. Examples of solvents include water, organic solvents, and mixtures of water and organic solvents. Examples of organic solvents include alcohols such as methanol, ethanol, propanol, and butanol; and ketones such as acetone and methyl ethyl ketone. When the solvent is a mixture of water and organic solvents, the content of organic solvent is preferably 65% ​​by mass or less based on the mass of the mixture.

[0104] From the viewpoint of appropriately controlling the timing of the reaction initiation, the reaction solution is preferably prepared by adding a ceramic precursor to a mixture containing a catalyst, a macropore-forming agent, and a mesopore-forming agent as needed. The reaction is initiated by adding the ceramic precursor to the mixture containing the catalyst, macropore-forming agent, and a mesopore-forming agent as needed.

[0105] While stirring the reaction solution, the solution can be cooled. Cooling of the reaction solution is preferably carried out at a temperature below 60°C, such that the temperature of the reaction solution is such that a sol-gel phase transition accompanied by a phase separation process (typically Spinardo decomposition) is easily achieved. It should be noted that the lower limit is a temperature at which the reaction solution will not freeze, for example, around 1°C.

[0106] For example, when using tetramethoxysilane, a half-metal compound having hydrolyzable functional groups, as a ceramic precursor, the above-mentioned cooling is suitable.

[0107] The reaction solution undergoes sol-gelation as the hydrolysis and condensation reactions proceed.

[0108] In the hydrolysis reaction, the hydrolyzable functional groups of the ceramic precursor are hydrolyzed to form hydroxyl groups. In the polycondensation reaction, metal oxoalkane oligomers are formed through dehydration condensation reactions between hydroxyl groups and de-alcoholization condensation reactions between hydroxyl groups and unhydrolyzed hydrolyzable functional groups. For example, when the ceramic precursor is a silicon compound with hydrolyzable functional groups, siloxane oligomers are formed through the dehydration condensation reaction shown in formula (1) and the de-alcoholization condensation reaction shown in formula (2). It should be noted that in formula (2) below, -OR represents an unhydrolyzed hydrolyzable functional group.

[0109] ≡Si-OH+HO-Si≡→≡Si-O-Si≡+H2O···(1)

[0110] ≡Si-OR+HO-Si≡→≡Si-O-Si≡+ROH···(2)

[0111] If further hydrolysis and condensation reactions occur, nano-sized metal oxoalkane oligomer primary particles are formed, which then aggregate to form secondary particles. This results in sol-gel formation of the reaction solution.

[0112] In the gel manufacturing process, the sol obtained from the sol-gel manufacturing process is molded as needed and then heated to the gelation temperature to produce a polyoxometalate gel. In the gelation process, further hydrolysis and polycondensation reactions are carried out to form a metaloxometalate polymer, inducing a sol-gel phase transition accompanied by a phase separation process (typically Spinardo decomposition), thus producing a polyoxometalate gel (wetted gel). The manufactured polyoxometalate gel has a co-continuous structure of a framework phase and a solvent phase. The metaloxometalate polymer generated through hydrolysis and polycondensation is rich in the framework phase, while the solvent is rich in the solvent phase. The framework and solvent phases each have a continuous three-dimensional network structure and are intertwined with each other, thereby forming a co-continuous structure of the framework and solvent phases.

[0113] Molding molds are used to mold gels into desired shapes. Examples of materials for molding molds include synthetic resins such as polystyrene, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate (PC), silicone, and polytetrafluoroethylene (PTFE); and metals such as aluminum and stainless steel.

[0114] From the viewpoint of appropriately forming a co-continuous structure of the framework phase and solvent phase in the gel, the gelation temperature is preferably 20°C or higher and 80°C or lower, more preferably 25°C or higher and 40°C or lower. The heating time at the gelation temperature is preferably 4 hours or higher and 24 hours or lower.

[0115] Process (b)

[0116] In step (b), pores are formed in the framework of the polyoxometalate gel manufactured in step (a).

[0117] Pore ​​formation in the framework of polyoxometalate gels can be performed using conventional methods. When forming pores in the framework of polyoxometalate gels, the polyoxometalate gel manufactured through step (a) can be reacted with a mesoporous forming agent, if necessary.

[0118] The description of the mesoporous forming agent is the same as above. The mesoporous forming agent can be contained in the polyoxometalate gel manufactured by step (a), in a reaction solution containing the polyoxometalate gel and the mesoporous forming agent, or in both. In step (b), pores are formed in the gel's framework (pores forming mesopores in the ceramic monolith). The reaction solution can contain one or more solvents. The description of the solvent is the same as above.

[0119] When reacting polyoxometalate gel with a mesoporous forming agent, the reaction can be carried out under heating and reflux.

[0120] The heating temperature during reflux is preferably 50°C or higher and 120°C or lower. Furthermore, the heating time during reflux is preferably 1 hour or higher and 36 hours or lower, more preferably 4 hours or 24 hours or lower.

[0121] When using a half-metal compound with hydrolyzable functional groups as a ceramic precursor, it is suitable to react the polyoxometalate gel with the mesoporous forming agent under heating and reflux.

[0122] Process (c)

[0123] In step (c), the polyoxometalate gel supplied to step (b) is cleaned and / or dried as needed, and then calcined to produce ceramic monoliths.

[0124] Examples of cleaning solutions used in cleaning include water, organic solvents, mixtures of water and organic solvents, and aqueous solutions containing acids or bases. Examples of organic solvents include alcohols such as methanol, ethanol, n-propanol, 2-propanol (IPA), and butanol. Examples of acids include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, acetic acid, formic acid, carbonic acid, citric acid, and phosphoric acid. Examples of bases include sodium hydroxide, potassium hydroxide, ammonia, water-soluble amines, sodium carbonate, and sodium bicarbonate.

[0125] Examples of drying methods include natural drying, heat drying, drying using solvents with low surface tension, drying based on freeze sublimation, and supercritical drying.

[0126] In the roasting process, the roasting temperature is preferably 500°C or higher and 1000°C or lower, more preferably 600°C or higher and 800°C or lower, and the roasting time is preferably 1 hour or higher and 8 hours or lower, more preferably 3 hours or higher and 5 hours or lower. Roasting is usually carried out in an atmospheric atmosphere.

[0127] The ceramic monolith has a co-continuous structure formed by a ceramic framework containing mesopores and macropores. The ceramic framework of the ceramic monolith is formed by the framework phase of the polyoxometalate gel, and the macropores of the ceramic monolith are formed by the solvent phase of the polyoxometalate gel.

[0128] In one embodiment, the ceramic monolith is a silica monolith. The silica monolith has a co-continuous structure formed by a silica framework containing mesopores and macropores.

[0129] In another embodiment, the ceramic monolith can be a monolith of alumina, tin oxide, cerium dioxide, titanium dioxide, or zirconium oxide. Similarly, in this case, the monolith has a co-continuous structure formed by a framework of mesoporous alumina, tin oxide, cerium dioxide, titanium dioxide, or zirconium oxide and macropores.

[0130] The manufactured ceramic blocks can be molded and used as adsorbent materials (e.g., adsorbent materials with columnar shapes), or they can be molded using a mold or the like, directly or as needed, and used as adsorbent materials (e.g., adsorbent materials with columnar shapes). For example, in a gel manufacturing process, molded ceramic blocks can be manufactured by using a molding die to shape the gel into the desired shape. It should be noted that the average diameter of the molded ceramic blocks is smaller than the average diameter of the gel obtained by molding using a mold.

[0131] The manufactured ceramic blocks can be pulverized and used as adsorbent materials. Pulverization can be carried out using conventional methods. Pulverization can be performed using, for example, a mortar and pestle mill, hammer mill, ball mill, bead mill, jet mill, roller mill, etc. The particle size of the pulverized adsorbent material is preferably 0.5 μm or more and 5.0 mm or less, more preferably 12.0 μm or more and 3.0 mm or less, and even more preferably 5.0 μm or more and 1.0 mm or less. It should be noted that "particle size" refers to the circle equivalent diameter, that is, the diameter of the circle in an observed image (e.g., SEM image) of the pulverized adsorbent material, assuming it has a circle with an area equal to that of the pulverized adsorbent material.

[0132] <Surface Modification>

[0133] In adsorbent materials, the surface of the ceramic framework is preferably modified with functional groups capable of adsorbing metals and / or metal ions. The surface of the ceramic framework can be modified with two or more functional groups capable of adsorbing metals and / or metal ions. The functional groups capable of adsorbing metals and / or metal ions can be directly bonded to the surface of the ceramic framework, or they can be bonded to the surface of the ceramic framework through linking groups.

[0134] The surface of the ceramic framework includes an inner surface and an outer surface. The inner surface of the ceramic framework includes macropores and mesopores existing within the ceramic framework (i.e., not exposed to the outer surface), while the outer surface of the ceramic framework includes macropores and mesopores exposed to the outer surface. At least the inner surface of the ceramic framework is preferably modified with functional groups capable of adsorbing metals and / or metal ions.

[0135] Examples of metals include scandium (Sc), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), manganese (Mn), vanadium (V), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), gold (Au), silver (Ag), rhenium (Re), and tungsten (W). Among these, from the viewpoint of high demand for adsorption and recovery, noble metals such as Pt, Pd, Rh, Ru, Ir, Os, Au, Ag, and Re are preferred; platinum group metals such as Pt, Pd, Rh, Ru, Ir, and Os are more preferred; and Pt, Pd, or Rh are even more preferred. Examples of the form in which the functional groups adsorb the metal include, for instance, metal nanoparticles.

[0136] Examples of metal ions include those of the aforementioned transition metals. From the same perspective, transition metal ions are preferably noble metal ions, more preferably platinum group metal ions, and even more preferably Pt, Pd, or Rh ions.

[0137] Examples of functional groups capable of adsorbing metals and / or metal ions include nitrogen-containing groups such as primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing nitrogen atoms; thiol, carboxyl, phosphine, phosphate, sulfate, hydroxyl, and ketone groups, preferably at least one selected from nitrogen-containing groups, thiol groups, and carboxyl groups. The nitrogen-containing group is preferably selected from at least one selected from primary amino, secondary amino, tertiary amino, imino, hypoazine, and heterocyclic groups containing nitrogen atoms, more preferably at least one selected from primary amino, secondary amino, tertiary amino, imino, and hypoazine groups.

[0138] Thiol groups can adsorb metals and / or metal ions such as silver, cobalt, copper, iron, iridium, nickel, osmium, palladium, gold, platinum, rhodium, ruthenium, scandium, zinc, and rhenium.

[0139] Carboxyl groups can adsorb metals and / or metal ions such as cobalt, chromium, copper, iron, iridium, nickel, osmium, palladium, rhodium, ruthenium, scandium, zinc, vanadium, manganese, and rhenium.

[0140] Primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group, and heterocyclic groups containing nitrogen atoms, etc., can adsorb metals and / or metal ions such as cobalt, chromium, copper, iron, nickel, osmium, palladium, platinum, rhodium, ruthenium, gold, iridium, tungsten, zinc, vanadium, manganese, and rhenium.

[0141] Primary amines are represented by the formula -NH2. Secondary amines are represented by the formula -NHR. 1 Represented by the formula -NR. Tertiary amines are represented by this formula. 1 R 2 It is indicated by the formula -N. Quaternary ammonium groups are represented by the formula -N. + R 1 R 2 R 3 Indicates. R 1 R 2 and R 3 Each amino group can be, for example, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted arylalkyl group, a substituted or unsubstituted alkylaryl group, etc. The secondary and tertiary amino groups can be aliphatic or aromatic, preferably aliphatic. Examples of aliphatic amino groups include R... 1 For substituted alkyl or non-substituted alkyl secondary amino groups, R 1 and R 2 Both are tertiary amino groups, such as substituted alkyl or unsubstituted alkyl groups. Examples of aromatic amino groups include R... 1 For substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, or substituted or unsubstituted alkylaryl secondary amino groups; R 1 and R 2 At least one of them is a substituted or unsubstituted aryl group, a substituted or unsubstituted arylalkyl group, or a tertiaryl amino group of a substituted or unsubstituted alkylaryl group. The quaternary ammonium group can be an aliphatic ammonium group or an aromatic ammonium group, preferably an aliphatic ammonium group. Examples of aliphatic ammonium groups include R. 1 R 2 and R 3 Each can be a quaternary ammonium group, either substituted or unsubstituted. Examples of aromatic ammonium groups include R... 1 R 2 and R 3 At least one of them is a substituted or unsubstituted aryl group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted alkylaryl quaternary group, etc.

[0142] The alkyl group is, for example, an alkyl group having 1 to 10 carbon atoms. The alkyl group can be straight-chain or branched. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 6, even more preferably 1 to 5, and even more preferably 1 to 4.

[0143] The aryl group is, for example, a monocyclic or polycyclic (e.g., bicyclic or tricyclic) aromatic hydrocarbon cyclic group with 4 to 14 carbon atoms. The polycyclic form can be a fused ring. Examples of aryl groups include phenyl and naphthyl groups. The number of carbon atoms in the aryl group is preferably 6 to 14, more preferably 6 to 10.

[0144] Arylalkyl is an alkyl group having one or more aryl groups, as explained above. The number of aryl groups in an arylalkyl group is, for example, 1, 2, or 3.

[0145] Alkyl aryl is an aryl group having one or more alkyl groups, as explained above. The number of alkyl groups in an alkyl aryl group is, for example, 1, 2, or 3.

[0146] Alkyl, aryl, arylalkyl, or alkylaryl groups may have, for example, 1, 2, or 3 substituents. Examples of substituents include hydroxyl, halogen atom, thiol group, carboxyl group, phosphate group, sulfate group, ketone group, alkoxy group, and oxygen group. The halogen atom is selected from fluorine, chlorine, bromine, and iodine atoms. The alkoxy group is a group represented by the formula -O-alkyl or aryl, and the relevant descriptions of alkyl groups are as described above.

[0147] Examples of secondary amino groups include aliphatic amino groups such as N-methylamino, N-ethylamino, N-propylamino, and N-isopropylamino; and aromatic amino groups such as N-phenylamino (aniline).

[0148] Examples of tertiary amino groups include aliphatic amino groups such as N,N-dimethylamino, N,N-diethylamino, N,N-methylethylamino, N,N-dipropylamino, and N,N-diisopropylamino; and aromatic amino groups such as N,N-diphenylamino.

[0149] Examples of quaternary ammonium groups include trimethylammonium, triethylammonium, and tributylammonium trialkylammonium groups. Examples of counterions relative to the nitrogen atom constituting the quaternary ammonium group include chloride ions, bromide ions, and hydroxide ions.

[0150] The imino group is a divalent group represented by the formula =NH or -NH-. The imino group can be bonded to one carbon atom via a double bond (i.e., C=NH) or to two carbon atoms via a single bond (i.e., C-NH-C), with the latter being preferred. Secondary amines (-NHR) 1The -NH- in ) can belong to an imino group, and the secondary amino group is preferably a terminal group. That is, secondary amino (-NHR) 1 R in ) 1 Preferably, it does not have at least one nitrogen-containing group selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and heterocyclic group containing nitrogen atoms.

[0151] The hypoazine group is a trivalent group represented by the formula ≡N or -N<. The hypoazine group can be bonded to one carbon atom via a triple bond (i.e., C≡N) or to three carbon atoms via a single bond (i.e., CN(-C)-C), preferably the latter. In the former case, the hypoazine group forms a cyano group (-CN) together with one carbon atom. Tertiary amine (-NR) 1 R 2 In the ), -N can be a hyponitro group, and the tertiary amino group is preferably a terminal group. That is, the tertiary amino group (-NR) 1 R 2 R in ) 1 and R 2 Preferably, it does not have at least one nitrogen-containing group selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and heterocyclic group containing nitrogen atoms.

[0152] A nitrogen-containing heterocyclic group is a monovalent group containing at least one (e.g., one, two, or three) nitrogen atoms as cyclic atoms. In addition to containing at least one nitrogen atom, the nitrogen-containing heterocyclic group may also contain one or more (e.g., one, two, or three) heteroatoms selected from oxygen and sulfur atoms as cyclic atoms. The nitrogen-containing heterocyclic group can be monocyclic or polycyclic (e.g., bicyclic or tricyclic). The number of ring elements in a monocyclic nitrogen-containing heterocyclic group is, for example, 3 to 8, preferably 5 or 6. The number of ring elements in a polycyclic nitrogen-containing heterocyclic group is, for example, 9 to 14, preferably 9 or 10. The nitrogen-containing heterocyclic group may or may not be aromatic (i.e., it can be an aromatic heterocyclic group or an aliphatic heterocyclic group). The nitrogen-containing heterocyclic group may have substituents. The number of substituents is, for example, 1, 2, or 3. Examples of substituents include hydroxyl, halogen atom, thiol group, carboxyl group, phosphate group, sulfate group, ketone group, alkoxy group, and oxygen group. Specific examples of halogens are described above. The relevant explanations for alkoxy groups are also described above.

[0153] Examples of nitrogen-containing heterocyclic groups include 5- or 6-membered monocyclic nitrogen-containing heterocyclic groups. Examples of aromatic 5- or 6-membered monocyclic nitrogen-containing heterocyclic groups include pyrroleyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, and pyrazinyl. Examples of non-aromatic 5- or 6-membered monocyclic nitrogen-containing heterocyclic groups include pyrroleyl, pyrazolylyl, imidazolyl, piperidinyl, piperazinyl, morpholinyl, and thiomorpholinyl. Non-aromatic 5- or 6-membered monocyclic heterocyclic groups containing nitrogen atoms may have one or two unsaturated bonds within the ring. Examples of such nitrogen-containing heterocyclic groups include 1,2-dihydropyridinyl, 1,4-dihydropyridinyl, and 1,2,5,6-tetrahydropyridinyl. Aromatic or non-aromatic 5- or 6-membered monocyclic heterocyclic groups containing nitrogen atoms may fused with a benzene ring. Examples of polycyclic (e.g., bicyclic or tricyclic) nitrogen-containing heterocyclic groups include indole, isoindole, indazole, benzimidazolyl, benzotriazolyl, oxazolopyrimidinyl, thiazopyrimidinyl, pyrrolopyrimidinyl, pyrrolopyrimidinyl, imidazopyrimidinyl, purine, quinolinyl, isoquinolinyl, boralinyl, phthalazinyl, quinazolinyl, quinoxalinyl, and naphthidyl.

[0154] The linking bonds of nitrogen-containing heterocyclic groups can be formed by any cyclic atom. The linking bonds of nitrogen-containing heterocyclic groups are usually formed by carbon or nitrogen atoms. When the linking bonds of a nitrogen-containing heterocyclic group are formed by a nitrogen atom, the nitrogen-containing heterocyclic group belongs to the heterocyclic amino group. Examples of aromatic 5- or 6-membered monocyclic heterocyclic amino groups include 1-pyrrolithyl, 1-imidazolyl, 1-pyrazolyl, 3-oxazolyl, 3-thiazolyl, 1-pyridinyl, 1-pyridazinyl, 1-pyrimidinyl, and 1-pyrazinyl. Examples of non-aromatic 5- or 6-membered monocyclic heterocyclic amino groups (i.e., alicyclic amino groups) include 1-pyrrolithyl, 1-pyrazolyl, 1-imidazolyl, 1-piperidinyl, 1-piperazinyl, morpholinyl, and thiomorpholinyl.

[0155] The amount of functional groups capable of adsorbing metals and / or metal ions contained in the adsorbent material, based on the mass of the adsorbent material, is preferably 0.10 mmol / g or more and 6.0 mmol / mL or less, more preferably 0.10 mmol / g or more and 4.0 mmol / g or less, further preferably 1.0 mmol / g or more and 3.0 mmol / g or less, and even more preferably 1.5 mmol / g or more and 2.5 mmol / g or less. The amount of functional groups can be determined by conventional methods. The amount of nitrogen-containing groups such as amino, imino, and hyponitro groups can be determined by the methods described in the examples below. The nitrogen-containing groups contained in the adsorbent material are derived from compounds containing nitrogen-containing groups that modify the surface of the ceramic framework. When the adsorbent material contains one type of nitrogen-containing group, "the amount of nitrogen-containing group" refers to the amount of that one type of nitrogen-containing group; when the adsorbent material contains two or more types of nitrogen-containing groups, "the amount of nitrogen-containing group" refers to the total amount of those two or more types of nitrogen-containing groups. In addition, "the amount of groups containing nitrogen atoms" refers to the amount converted from nitrogen atoms.

[0156] Adsorbent materials whose ceramic framework surfaces are modified with functional groups capable of adsorbing metals and / or metal ions exhibit superior adsorption performance compared to conventional adsorbent materials (e.g., mesoporous silica, ion exchange resins, etc.). Adsorption performance can be evaluated based on the adsorption rate (the percentage of metals and / or metal ions adsorbed by the adsorbent material relative to the amount of metals and / or metal ions initially present in the solution), calculated based on the amount of metals and / or metal ions adsorbed by the adsorbent material when a solution containing metals and / or metal ions is contacted with the adsorbent material. Alternatively, adsorption performance can be evaluated based on the adsorption rate or adsorption speed, calculated based on the amount of metals and / or metal ions adsorbed by the adsorbent material when a solution containing metals and / or metal ions is contacted with the adsorbent material for a specified time, and calculated by dividing the amount of metals and / or metal ions adsorbed by the adsorbent material by the specified time. In this invention, adsorption performance refers to both adsorption rate and adsorption speed. From the viewpoint of prioritizing the recovery rate of the adsorbed substance when commercializing adsorbent materials, adsorption speed is given priority over adsorption rate in this invention.

[0157] Generally, the more functional groups capable of adsorbing metals and / or metal ions introduced onto the surface of an adsorbent material, the better its adsorption performance. However, when nitrogen-containing groups capable of adsorbing metals and / or metal ions are introduced onto the surface of a ceramic framework, if the amount of these nitrogen-containing groups is excessive, the hydrophobicity of the adsorbent material increases, making it difficult for solutions containing metals and / or metal ions to reach the pores and effectively utilize the introduced functional groups, thus reducing adsorption performance. Therefore, the amount of nitrogen-containing groups capable of adsorbing metals and / or metal ions contained in the adsorbent material, based on the mass of the adsorbent material, is preferably 1.5 mmol / g or more and 5.4 mmol / g or less, more preferably 1.8 mmol / g or more and 4.5 mmol / g or less, and even more preferably 2.0 mmol / g or more and 4.0 mmol / g or less. The nitrogen-containing groups capable of adsorbing metals and / or metal ions contained in the adsorbent material are derived from compounds containing nitrogen-containing groups that modify the surface of the ceramic framework. When the adsorbent material contains one type of nitrogen-containing group capable of adsorbing metals and / or metal ions, the "amount of nitrogen-containing groups" refers to the amount of that single nitrogen-containing group. When the adsorbent material contains two or more types of nitrogen-containing groups capable of adsorbing metals and / or metal ions, the "amount of nitrogen-containing groups" refers to the total amount of those two or more nitrogen-containing groups. Furthermore, the "amount of nitrogen-containing groups" refers to the amount converted from nitrogen atoms. The amount of nitrogen-containing groups can be determined using conventional methods. For example, the amount of nitrogen-containing groups can be determined using the methods described in the examples below.

[0158] Methods for introducing desired functional groups onto the surface of a ceramic framework include, for example, chemically fixing a compound with the desired functional group onto the surface of the ceramic framework via covalent bonds; and physically fixing a compound with the desired functional group onto the surface of the ceramic framework via physical interactions such as ionic bonds and hydrophobic interactions. Methods for chemically introducing desired functional groups onto the surface of a ceramic framework include, for example, reacting a functional group (e.g., hydroxyl group) on the surface of the ceramic framework with a silane coupling agent having the desired functional group, thereby chemically fixing the silane coupling agent having the desired functional group onto the surface of the ceramic framework.

[0159] In one embodiment, the surface of a ceramic framework is modified with nitrogen-containing groups by immobilizing a compound having nitrogen-containing groups onto the surface of the ceramic framework. Examples of methods for introducing a compound having nitrogen-containing groups onto the surface of the ceramic framework include: chemically immobilizing a compound having nitrogen-containing groups (e.g., a silane coupling agent having nitrogen-containing groups) onto the surface of the ceramic framework via covalent bonds; and physically immobilizing a compound having nitrogen-containing groups onto the surface of the ceramic framework via physical interactions such as ionic bonds or hydrophobic interactions. Examples of methods for chemically introducing a compound having nitrogen-containing groups onto the surface of the ceramic framework include: reacting functional groups (e.g., hydroxyl groups) on the surface of the ceramic framework with a silane coupling agent containing nitrogen-containing groups, thereby chemically immobilizing the silane coupling agent onto the surface of the ceramic framework. Compounds having nitrogen-containing groups can be immobilized on the surface of the ceramic framework via linking groups. For example, after introducing a functional group that reacts with a compound containing a nitrogen atom onto the surface of a ceramic framework, the introduced functional group reacts with the compound containing a nitrogen atom, thereby chemically fixing the compound containing a nitrogen atom onto the surface of the ceramic framework. As a method for introducing a functional group that reacts with a compound containing a nitrogen atom onto the surface of a ceramic framework, one example is reacting a functional group (e.g., hydroxyl group) on the surface of the ceramic framework with a silane coupling agent having a functional group that reacts with a compound containing a nitrogen atom, thereby chemically fixing the silane coupling agent onto the surface of the ceramic framework. Examples of silane coupling agents having a functional group that reacts with a compound containing a nitrogen atom include, for example, silane coupling agents having an epoxy group and / or a halogenated alkyl group. Examples of epoxy-containing silane coupling agents include 3-glycidoxypropyltrimethoxysilane. Examples of halogenated silane coupling agents include 3-chloropropyltrimethoxysilane.

[0160] Amine compounds can be used as compounds containing a nitrogen atom. There are no particular limitations on whether an amine compound contains at least one nitrogen-containing group selected from primary amine, secondary amine, tertiary amine, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing a nitrogen atom. In an amine compound, the portion other than the nitrogen-containing group can be composed of hydrogen and carbon atoms, or it can contain one or more other elements (e.g., oxygen, sulfur, halogen, silicon, etc.) in addition to hydrogen and carbon atoms.

[0161] As an amine compound, at least one selected from monoamines, diamines, triamines, and polyamines may be used. Two or more amine compounds may be used. The amine compound may be a silane coupling agent.

[0162] As a silane coupling agent comprising at least one nitrogen-containing group selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and heterocyclic group containing a nitrogen atom, examples of silane coupling agents represented by formulas A, B or C below are provided.

[0163] Formula A: R a -R d -Si(-R b ) n (-R c ) 3-n

[0164] Formula B: R a -R d -NH-R e -Si(-R b ) n (-R c ) 3-n

[0165] Formula C: R a -R d -NH-R e -NH-R f -Si(-R b ) n (-R c ) 3-n

[0166] In equations A, B, and C, R a Represents a primary amino group, secondary amino group, tertiary amino group, quaternary ammonium group, or a heterocyclic group containing a nitrogen atom, with n R groups. b Each of the following independently represents a straight-chain or branched alkyl group having 1 to 10 carbon atoms, preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and even more preferably 1 to 4, and (3-n) R c Each group independently represents a straight-chain or branched alkoxy or halogen group having 1 to 10 carbon atoms, preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and even more preferably 1 to 4. d R e and R f Each of the following independently represents a linear or branched alkylene group having 1 to 10 carbon atoms, preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and even more preferably 1 to 4 carbon atoms; an aryl group having 4 to 14 carbon atoms, preferably 6 to 14, and even more preferably 6 to 10 carbon atoms; or a combination thereof, where n represents an integer from 0 to 2. Alkylenes and aryl groups are divalent functional groups formed by removing one hydrogen atom from alkyl and aryl groups, respectively, as described above.

[0167] Ra Preferably selected from primary amino, secondary amino, tertiary amino and heterocyclic groups containing nitrogen atoms, more preferably selected from primary amino, secondary amino and tertiary amino.

[0168] As R b The alkyl groups shown can be exemplified by, for example, methyl, ethyl, propyl, butyl, etc.

[0169] As R c Examples of alkoxy or halogen groups shown include methoxy, ethoxy, propoxy, butoxy, chloro, bromo, and iodo groups. R c Of the alkoxy groups shown, methoxy or ethoxy is preferred. c Of the halogen groups shown, the chlorine group is preferred.

[0170] As R d R e or R f Examples of alkylene compounds include methylene, ethylene, propylene, and butylene.

[0171] As R d R e or R f Examples of arylene groups shown include phenylene, naphthylene, and biphenylene.

[0172] As R d R e or R f The combinations of alkylene and aryl groups shown can be exemplified by groups represented by formulas such as -XY-, -YX-, -XYX-, or -YXY-. In these formulas, X represents an alkylene group and Y represents an aryl group.

[0173] R d R e and R f The alkylene, arylene, or combinations thereof shown may optionally have substituents. The number of substituents may be, for example, 1, 2, or 3. Examples of substituents include, for example, hydroxyl, halogen atom, thiol group, carboxyl group, phosphate group, sulfate group, ketone group, alkoxy group, and oxygen group. Specific examples of halogens are as described above. Related explanations of alkoxy groups are as described above.

[0174] The monoamine has one nitrogen-containing group selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing a nitrogen atom. Examples of monoamines include silane coupling agents of formula A, such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, and 3-(4-pyridyl)propyltrimethoxysilane.

[0175] The diamine has two nitrogen-containing groups selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing nitrogen atoms. The two nitrogen-containing groups may be the same or different. Examples of diamines include silane coupling agents as shown in Formula B, such as 3-(2-aminoethylamino)propyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride.

[0176] Triamines have three nitrogen-containing groups selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing nitrogen atoms. The three nitrogen-containing groups may be the same or different. Examples of triamines include silane coupling agents of formula C, such as 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane.

[0177] Polyamines have four or more nitrogen-containing groups selected from primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypoazine, and heterocyclic groups containing nitrogen atoms. The four or more nitrogen-containing groups may be the same or different. Examples of polyamines include polyalkylimides, polyethyleneimine, and polyallylamine.

[0178] Examples of polyalkylene imides include polymers obtained by polymerizing one or more alkylene amines using conventional methods. Polyalkylene imides can be polymers that are chemically modified by reacting a polymer obtained by polymerizing one or more alkylene amines using conventional methods with a desired compound. Polyalkylene imides can be linear or branched. Examples of polyalkylene imides include triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, polypropyleneimine, and polybutyleneimine.

[0179] The weight-average molecular weight of polyalkylimide is, for example, 146 or more and 30,000 or less, preferably 146 or more and 15,000 or less, more preferably 146 or more and 5,000 or less, and even more preferably 146 or more and 1,800 or less. The weight-average molecular weight of polyvinylamine is, for example, 174 or more and 25,000 or less, preferably 174 or more and 6,000 or less. The weight-average molecular weight of polyallylamine is, for example, 230 or more and 150,000 or less, preferably 230 or more and 15,000 or less, more preferably 230 or more and 8,000 or less, and even more preferably 230 or more and 5,000 or less. It should be noted that the weight-average molecular weight can be determined, for example, by gel permeation chromatography (GPC) using polystyrene as a standard.

[0180] Process (3)

[0181] In step (3), the treatment liquid prepared in step (1) is brought into contact with the adsorbent material prepared in step (2).

[0182] Methods for bringing the target liquid into contact with the adsorbent material include, for example, immersing the adsorbent material in the target liquid; and introducing the target liquid into a column filled with adsorbent material. The introduction of the liquid can be performed using, for example, a liquid pump.

[0183] When the target liquid is brought into contact with the adsorbent material, the metals and / or metal ions contained in the target liquid are adsorbed by the adsorbent material. Adsorbent materials having a co-continuous structure formed by a ceramic framework containing mesopores and macropores, wherein the surface of the ceramic framework is modified with functional groups capable of adsorbing metals and / or metal ions, and the modal pore size of the macropores before modification with the aforementioned functional groups is 0.20 μm or more and 4.0 μm or less, and the modal pore size of the mesopores before modification with the aforementioned functional groups is 2.0 nm or more and 50 nm or less, are particularly useful for recovering metals and / or metal ions from target liquids with low concentrations of metals and / or metal ions (e.g., 0.2 ppm or more and 300 ppm or less, especially 0.2 ppm or more and 200 ppm or less).

[0184] After step (3), the adsorbent material containing the metal and / or metal ions is separated from the liquid to be treated by solid-liquid separation, such as filtration. When the adsorbent material has a columnar shape, it is also advantageous that the liquid to be treated can be easily separated from the adsorbent material by solid-liquid separation, such as filtration, after the liquid to be treated has been brought into contact with the adsorbent material.

[0185] Process (4)

[0186] In step (4), the adsorbent material supplied to step (3) is brought into contact with an acidic solution.

[0187] Examples of acids included in an acidic solution include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; and organic acids such as acetic acid, citric acid, and oxalic acid. Examples of solvents included in an acidic solution include water. An acidic solution may be, for example, an aqueous solution of hydrochloric acid. The amount of acid in the acidic solution can be adjusted appropriately depending on the type of acid. When the acidic solution is an aqueous solution of hydrochloric acid, the concentration of the aqueous solution is, for example, 0.5 mol / L or more and 12 mol / L or less, more preferably 1 mol / L or more and 12 mol / L or less, and even more preferably 3 mol / L or more and 12 mol / L or less.

[0188] An acidic solution can be a mixture of two or more acids. Examples of mixtures of two or more acids include aqua regia (a mixture of concentrated hydrochloric acid and concentrated nitric acid). The volume ratio of concentrated hydrochloric acid to concentrated nitric acid is usually 3:1.

[0189] As a method for contacting the adsorbent material supplied to step (3) with the acidic solution, examples include: immersing the adsorbent material supplied to step (3) in the acidic solution; and passing the acidic solution into a column filled with the adsorbent material supplied to step (3). The passing solution can be performed using, for example, a liquid pump.

[0190] If the adsorbent material supplied to step (3) is brought into contact with an acidic solution, the metal and / or metal ions will detach from the adsorbent material and be released into the acidic solution. Thus, an acidic solution containing the metal and / or metal ions is obtained.

[0191] Step (4) can be performed more than twice. For example, after the first step (4), the adsorbent material can be separated by solid-liquid separation such as filtration, and the second and subsequent steps (4) can be performed using the same or different acidic solution as the first step (4). This can improve the detachment rate of the self-adsorbed metal and / or metal ion material.

[0192] After step (4), the adsorbent material is separated from the acidic solution by solid-liquid separation, such as filtration.

[0193] Process (5)

[0194] In step (5), metals and / or metal ions are recovered from the acidic solution supplied to step (4).

[0195] The recovered metals and / or metal ions are processed using conventional methods, including separation, concentration, and refining.

[0196] The Second Method

[0197] The second method of the present invention is a method for regenerating the adsorbent material used in the first method of the present invention, which includes a step of contacting the adsorbent material supplied to step (4) with an alkaline solution.

[0198] Examples of bases that can be included in an alkaline solution include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, and ammonia. Examples of solvents that can be included in an alkaline solution include water, methanol, ethanol, and other alcohols. An alkaline solution may be, for example, an aqueous solution of sodium hydroxide or an aqueous solution of sodium carbonate. The amount of base in an alkaline solution can be adjusted appropriately depending on the type of base. When the alkaline solution is an aqueous solution of sodium hydroxide, the concentration of the sodium hydroxide solution is, for example, 0.5 w / w% or more and 30 w / w% or less. When the alkaline solution is an aqueous solution of sodium carbonate, the concentration of the sodium carbonate solution is, for example, 0.5 mol / L or more and 5 mol / L.

[0199] By contacting the adsorbent material supplied in step (4) (e.g., adsorbent material separated from an acidic solution by solid-liquid separation such as filtration) with an alkaline solution, the adsorbent material can be regenerated. The regenerated adsorbent material can be separated from the alkaline solution by solid-liquid separation such as filtration, and after washing and drying as needed, it can be used again as an adsorbent material. As described above, adsorbent materials that combine adsorption performance and durability (preferably adsorbent materials with a columnar shape having an average diameter of 1.5 mm or more and 20 mm or less, more preferably adsorbent materials with a columnar shape having an average diameter of 1.5 mm or more and 20 mm or less and an aspect ratio of 0.70 or more) are particularly useful for repeated regeneration and use for adsorbing metals and / or metal ions. Adsorbent materials that combine adsorption performance and durability can also exhibit excellent adsorption performance when repeatedly regenerated and used.

[0200] Example

[0201] The present invention will now be described in more detail based on manufacturing examples and test examples, but the scope of the present invention is not limited to the manufacturing examples and test examples at all.

[0202] [Manufacturing Example 1]

[0203] (1) Production of silica monoliths

[0204] Add 9.10 g of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH), 7.80 g of urea, and 86.7 g of a 6.06% by mass aqueous solution of acetic acid to a 150 mL reaction vessel and stir at room temperature for 10 minutes. Place the reaction vessel in an ice bath and cool the reaction solution while stirring for 15 minutes. Add 43.3 g of tetramethoxysilane to the cooled reaction solution and stir while cooling in an ice bath for 30 minutes. Add a mold to the reaction vessel to form cylindrical silica monoliths with an average diameter of 4.6 mm. Heat the reaction solution in a 30°C bath and then let it stand overnight in a 30°C incubator to prepare a polysiloxane gel.

[0205] Next, the obtained polysiloxane gel was added to another reaction vessel containing 100 mL of 3 mol / L urea solution, and the mixture was heated under reflux for 24 hours. After the reaction was completed, the obtained polysiloxane gel was washed with water and dried in a dryer set to 60°C for 12 hours. After drying, it was calcined at 600°C for 5 hours in air to obtain 15 g of cylindrical silica monoliths with an average diameter of 4.6 mm. The obtained silica monoliths were cut to adjust the length to 7.4 mm to produce silica monoliths with an aspect ratio of 1.6.

[0206] (2) Observation based on scanning electron microscopy

[0207] The surface structure of the silica monoparticles obtained in (1) above was observed using a scanning electron microscope (JEOL JSM-7900F). The observation results are shown below. Figure 4A and Figure 4B .like Figure 4A and Figure 4B As shown, the monolithic silica particles have a co-continuous structure formed by a silica framework containing mesopores and macropores. It should be noted that... Figure 4B symbols in Figure 3 The symbols in the text have the same meaning.

[0208] (3) Determination of specific surface area and mode pore size of mesopores

[0209] Specific surface area and mode pore size were determined using a Microtrac-Bel surface area-pore size distribution measuring device, the "BELSORP-miniX". For single silica pellets degassed under reduced pressure at 400°C for 3 hours, the nitrogen adsorption and desorption amounts at 77K were measured using liquid nitrogen and a multi-point method. Adsorption-desorption isotherms were derived, and the specific surface area and mode pore size were calculated from these isotherms. Specific surface area was calculated using the BET method, and mode pore size was calculated using the BJH method.

[0210] The BJH method is a method for analyzing the distribution of pore volume relative to diameter of assumed cylindrical pores, based on the Barrett-Joyner-Halenda standard model (see J. Amer. Chem. Soc., 73, 373, 1951, etc. for details). In this invention, the analysis is performed within the range of pores with diameters of 2–200 nm.

[0211] (4) Determination of total pore volume, mode diameter of macropores and porosity

[0212] The total pore volume, mode pore size of macropores, and porosity were determined using a mercury porosimeter (Micromeritics AutoPore IV 9520). In mercury porosimetry, pressure is applied to the pores of a single silica pellet to allow mercury to penetrate. The pore volume and specific surface area are calculated based on the pressure and the amount of mercury injected. The pore size is calculated using the relationship between pore volume and specific surface area when the pores are assumed to be cylindrical. In this invention, analysis was performed using mercury porosimetry within a pore diameter range of 50 nm to 500 μm. The measurements were conducted under the following conditions and procedures.

[0213] (Measurement conditions)

[0214] Mercury parameters

[0215] Forward contact angle: 130.0°

[0216] Retreating contact angle: 130.0°

[0217] Surface tension: 485.0 mN / m (485.0 dynes / cm)

[0218] Mercury density: 13.5335 g / mL

[0219] Low-pressure parameters

[0220] Exhaust pressure: 50 μmHg

[0221] Exhaust time: 5.0 minutes

[0222] Mercury injection pressure: 0.0035 MPa

[0223] Balance time: 10 seconds

[0224] High pressure parameters

[0225] Balance time: 10 seconds

[0226] • Press-in volume: Adjusted to a level of 25% to 90%.

[0227] • Measurement environment: 20℃

[0228] (Measurement Procedure)

[0229] (i) Weigh approximately 0.5 g of the sample and place it into a sample dish, then enter the weighing value.

[0230] (ii) Measure the range of 0.0048 to 0.2068 MPa in the low-pressure section.

[0231] (iii) The range of 0.2068 to 255.1060 MPa was measured in the high-pressure section.

[0232] (ii) and (iii) are performed automatically using the software provided with the device.

[0233] The results of (3) and (4) above are shown in Table 1.

[0234] [Table 1]

[0235]

[0236] [Manufacturing Examples 2-8]

[0237] Using a mold for forming cylindrical silica monoliths with an average diameter of 1.2 mm, 1.5 mm, 3.0 mm, 3.7 mm, 6.0 mm, 11.0 mm, or 20.0 mm, the length of the resulting cylindrical silica monoliths with an average diameter of 1.2 mm, 1.5 mm, 3.0 mm, 3.7 mm, 6.0 mm, 11.0 mm, or 20.0 mm is adjusted to an aspect ratio of 1.6 as described in Table 2. Otherwise, the cylindrical silica monoliths are produced in the same manner as in Manufacturing Example 1.

[0238] [Manufacturing Examples 9-13]

[0239] The length of the silica monoliths was adjusted as described in Table 3 with aspect ratios of 0.5, 0.9, 1.0, 1.9 or 3.3. Otherwise, cylindrical silica monoliths were produced in the same manner as in Manufacturing Example 1.

[0240] [Experimental Example 1] Granular Strength Test

[0241] Using a KHT-40N digital hardness tester (3mm pressure diameter) manufactured by Fujiwara Corporation, pressure was applied to the sides of the dried silica monoliths obtained in Manufacturing Examples 1-13, and the pressure (N) at which they were damaged was measured. Similarly, for silica monoliths that had been immersed in pure water for 30 minutes and were in a water-absorbing state, the same procedure was performed to measure the pressure (N) at which they were damaged. It should be noted that the strength test of the silica monoliths in each manufacturing example was conducted using five lithograms, and the arithmetic mean of the five measurements was calculated. The measurement results are shown in Tables 2 and 3.

[0242] [Table 2]

[0243]

[0244] [Table 3]

[0245]

[0246] [Manufacturing Example 14]

[0247] 10.0 g of silica monoparticles obtained in Manufacturing Example 1 were added to a reaction vessel, followed by 60 mL of toluene and 7.45 g of 3-aminopropyltrimethoxysilane. The mixture was then heated under reflux at 110 °C for 12 hours. The silica monoparticles were separated from the toluene solution by filtration, washed three times with 30 mL of ethanol, and dried under reduced pressure to obtain 12.0 g of silica monoparticle adsorbent material.

[0248] The silica monolithic adsorbent material obtained in Manufacturing Example 14 was observed using a scanning electron microscope, following the same procedure as in Manufacturing Example 1. The observation results are shown below. Figure 5 .like Figure 5 As shown, presented with Figure 4A and Figure 4B With the same appearance, the silica monolithic adsorbent has a co-continuous structure formed by a silica framework containing mesopores and macropores.

[0249] The strength of the silica monolithic adsorbent material obtained in Manufacturing Example 14 was determined using the same procedure as in Experimental Example 1. The results are shown in Table 4.

[0250] [Table 4]

[0251]

[0252] The amount of nitrogen-containing groups (-NH2) in the monolithic silica adsorbent material obtained in Manufacturing Example 14 was quantified using an oxygen, nitrogen, and hydrogen analysis apparatus ONH836 manufactured by LECO JAPAN. The quantification results are shown in Table 5A.

[0253] [Manufacturing Example 15]

[0254] Instead of the silica monoliths obtained in Manufacturing Example 1, the silica monoliths obtained in Manufacturing Example 4 were used, and the silica monolith adsorbent material was prepared in the same manner as in Manufacturing Example 14. The amount of nitrogen-containing groups (-NH2) in the silica monolith adsorbent material obtained in Manufacturing Example 15 was quantified in the same manner as in Manufacturing Example 14. The quantification results are shown in Table 5A.

[0255] [Manufacturing Example 16]

[0256] Instead of the silica monoliths obtained in Manufacturing Example 1, the silica monoliths obtained in Manufacturing Example 6 were used, and the silica monolith adsorbent material was prepared in the same manner as in Manufacturing Example 14. The amount of nitrogen-containing groups (-NH2) in the silica monolith adsorbent material obtained in Manufacturing Example 16 was quantified in the same manner as in Manufacturing Example 14. The quantification results are shown in Table 5A.

[0257] [Manufacturing Example 17]

[0258] Instead of the silica monoliths obtained in Manufacturing Example 1, the silica monoliths obtained in Manufacturing Example 7 were used, and the silica monolith adsorbent material was prepared in the same manner as in Manufacturing Example 14. The amount of nitrogen-containing groups (-NH2) in the silica monolith adsorbent material obtained in Manufacturing Example 17 was quantified in the same manner as in Manufacturing Example 14. The quantification results are shown in Table 5A.

[0259] [Experimental Example 2A] Metal Adsorption Test Based on Solution Immersion

[0260] Each of the silica monoliths used in Examples 14-17 was immersed in 30 mL of an aqueous solution containing 100 ppm each of platinum nitrate, palladium nitrate, and rhodium nitrate, and stirred at room temperature for 30 minutes. After the reaction, the silica monoliths were separated by filtration, and the amount of metal elements in the resulting filtrate was analyzed using an ICP-based luminescence analyzer (HITACHI, PS3520 UVDD). The percentage of platinum adsorbed by the silica monoliths relative to the initial amount of platinum in the aqueous solution (hereinafter referred to as "platinum adsorption rate"), the percentage of palladium adsorbed by the silica monoliths relative to the initial amount of palladium in the aqueous solution (hereinafter referred to as "palladium adsorption rate"), and the percentage of rhodium adsorbed by the silica monoliths relative to the initial amount of rhodium in the aqueous solution (hereinafter referred to as "rhodium adsorption rate") were calculated. The platinum adsorption rate, palladium adsorption rate, and rhodium adsorption rate are shown in Table 5A. It should be noted that ">95" in Table 5A indicates that the value exceeds 95% of the guaranteed value for analysis.

[0261] [Table 5A]

[0262]

[0263] [Experimental Example 2B] Metal Adsorption Test Based on Solution Immersion

[0264] 2.5 g of the silica monolithic adsorbent material from Example 14 was immersed in 50 mL of an aqueous solution (containing 10 ppm of each of the metal elements Cd, Cr, Co, Cu, Fe, Mn, Ni, Ag, V, and Zn) obtained by diluting TraceCERTTransition metal mix 1 for ICP solution (manufactured by SIGMA-ALDRICH) 10 times with pure water. The solution was allowed to stand at room temperature for 24 hours. After the reaction, the silica monolithic adsorbent material was separated by filtration, and the amount of metal elements in the resulting filtrate was analyzed using an ICP luminescence analyzer (manufactured by HITACHI, PS3520UVDD). For each metal element, the percentage of the metal element adsorbed by the silica monolithic adsorbent material relative to the initial amount of metal element in the aqueous solution was calculated (hereinafter referred to as the "adsorption rate"). The adsorption rates of each metal element are shown in Table 5B.

[0265] [Table 5B]

[0266] Metal elements Cd Cr Co Cu Fe Mn Ni Ag V Zn Adsorption rate (%) 8 51 8 42 68 7 7 93 79 43

[0267] [Experimental Example 2C] Metal Adsorption Test Based on Solution Immersion

[0268] 2.5 g of the silica monolithic adsorbent material from Example 14 was immersed in 50 mL of an aqueous solution (containing 10 ppm of each of the metal elements Au, Ir, Os, Pd, Pt, Rh, and Ru) obtained by diluting TraceCERTTransition metal mix 3 for ICP solution (manufactured by SIGMA-ALDRICH) 10 times with pure water. The solution was allowed to stand at room temperature for 24 hours. After the reaction, the silica monolithic adsorbent material was separated by filtration, and the amount of metal elements in the resulting filtrate was analyzed using an ICP luminescence analyzer (HITACHI, PS3520 UVDD). For each metal element, the percentage of the metal element adsorbed by the silica monolithic adsorbent material relative to the initial amount of metal element in the aqueous solution was calculated (hereinafter referred to as the "adsorption rate"). The adsorption rates of each metal element are shown in Table 5C. It should be noted that ">95%" in Table 5C indicates exceeding 95% of the analytical guarantee value under the conditions of this determination.

[0269] [Table 5C]

[0270] Metal elements Au Ir Os Pd Pt Rh Ru Adsorption rate (%) 54 ＞95 ＞95 ＞95 ＞95 89 92

[0271] [Manufacturing Example 18]

[0272] In the preparation of the silica monoliths, the amount of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH) was changed to 8.7g, and the same operation as in Manufacturing Example 1 was performed to prepare the silica monoliths. Using the obtained silica monoliths, the same operation as in Manufacturing Example 14 was performed to prepare silica monolithic adsorbent material.

[0273] [Manufacturing Example 19]

[0274] In the preparation of the silica monoliths, the amount of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH) was changed to 9.5g. Otherwise, the same procedure as in Manufacturing Example 1 was followed to prepare the silica monoliths. Using the obtained silica monoliths, the same procedure as in Manufacturing Example 14 was followed to prepare the silica monolith adsorbent material.

[0275] [Manufacturing Example 20]

[0276] In the preparation of silica monoliths, instead of using 3 mol / L urea solution for 24 hours of heating and reflux, 1.5 mol / L urea solution was used for 12 hours of heating and reflux. Otherwise, the same procedure as in Manufacturing Example 1 was followed to prepare silica monoliths. Using the obtained silica monoliths, silica monolithic adsorbent material was prepared in the same procedure as in Manufacturing Example 14.

[0277] [Manufacturing Example 21]

[0278] In the preparation of silica monoliths, instead of using 3 mol / L urea solution for 24 hours of heating and reflux, 1.5 mol / L urea solution was used for 4 hours of heating and reflux. Otherwise, the same procedure as in Manufacturing Example 1 was followed to prepare silica monoliths. Using the obtained silica monoliths, silica monolithic adsorbent material was prepared in the same procedure as in Manufacturing Example 14.

[0279] For the silica monolithic adsorbent materials obtained in Manufacturing Examples 14 and 18-21, the same procedure as in Manufacturing Example 1 was followed to determine the amount of nitrogen-containing groups (-NH2), specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores, and porosity. The measurement results are shown in Table 6.

[0280] [Table 6]

[0281]

[0282] [Experimental Example 3] Metal Adsorption Test Based on Solution Immersion

[0283] For the silica monolithic adsorbent materials obtained in Manufacturing Examples 14 and 18-21, metal adsorption tests were conducted in the same manner as in Test Example 2A. The platinum adsorption rate, palladium adsorption rate, and rhodium adsorption rate are shown in Table 7. It should be noted that ">95" in Table 7 indicates that it exceeds 95% as an analytical guarantee value.

[0284] [Table 7]

[0285]

[0286] [Experimental Example 4] Metal Adsorption Experiment Based on Solution Flow

[0287] 3.0 g of silica granular adsorbent material with an average diameter of 4.6 mm, obtained from manufacturing examples 14, 18, 19, and 21, was filled into a stainless steel column (20 mm in diameter and 50 mm in length) and connected to a liquid delivery pump via stainless steel piping, thereby producing... Figure 6 The flow adsorption device shown.

[0288] exist Figure 6 In the diagram, symbol 60 represents a flow adsorption device, symbol 61 represents a stainless steel column, symbol 62 represents a stainless steel pipe, symbol 63 represents a liquid delivery pump, symbol 64 represents a recovery container, and the arrow indicates the direction of liquid flow.

[0289] Pure water was pumped at a flow rate of 5 mL / min for 2 minutes to fill the flow path. Then, an aqueous solution containing 10 ppm each of platinum nitrate, palladium nitrate, and rhodium nitrate was pumped at a flow rate of 0.5 mL / min. Ten minutes after the start of pumping, 100 mL of the aqueous solution passing through the column was collected in a container. This collection operation was repeated 10 times. The metal content of the collected aqueous solutions was analyzed using an ICP-based luminescence analyzer (HITACHI PS3520UVDD). The platinum, palladium, and rhodium adsorption rates were calculated using the same procedure as in Example 2A. The results are shown in Tables 8A and 8B. It should be noted that ">95" in Tables 8A and 8B indicates exceeding 95% of the analytical guarantee value.

[0290] [Table 8A]

[0291]

[0292] [Table 8B]

[0293]

[0294] [Manufacturing Example 22]

[0295] (1) Fabrication of a single silicon dioxide block

[0296] Using the sol-gel manufacturing apparatus described in Japanese Patent No. 6924338, silica monoliths were produced as follows: Tetramethoxysilane was continuously supplied to the mixing section at a flow rate of 45 mL / min, and an aqueous solution was continuously supplied at a flow rate of 90 mL / min. The mixture was then prepared by dissolving 171 g of polyethylene glycol 10000 (as a macropore forming agent), 180 g of urea (as a mesopore forming agent), and 1.2 g of acetic acid (as a catalyst) in 2000 g of deionized water. The mixture was discharged from the mixing section through a discharge pipe connected to the mixing section while being cooled with cooling water at 2°C. The mixture discharged from the discharge pipe was collected in a beaker cooled with cooling water at 15°C and stirred for 30 minutes. After stirring, the solution was collected in a gelation container (600 mL), and a mold for forming cylindrical silica monoliths with an average diameter of 4.6 mm was added. The mixture was then allowed to stand at 30 °C for 19 hours to prepare a polysiloxane gel.

[0297] Next, the obtained polysiloxane gel was added to a reaction vessel containing 10 L of 3M urea solution, and the mixture was refluxed at 90°C for 12 hours. After reflux, the obtained polysiloxane gel was washed with water and dried in a dryer set to 60°C for 20 hours. After drying, it was calcined at 600°C in air for 5 hours to produce silica monoliths.

[0298] (2) Fabrication of silica monolithic adsorbent material

[0299] One kilogram of silica monoliths obtained in step (1) was added to a reaction vessel containing 3.5 L of a mixed solution of acetic acid aqueous solution (acetic acid concentration: 0.3% by mass) and ethanol, and 4.16 mol of 3-mercaptopropyltrimethoxysilane. The mixture was then heated under reflux at 90 °C for 5 hours. The silica monoliths were separated from the solution by filtration, washed three times with deion-exchanged water, and dried in a dryer set at 80 °C for 20 hours to obtain silica monolith adsorbent material.

[0300] [Experimental Example 5] Metal Adsorption Test Based on Solution Immersion

[0301] 0.5 g of the thiol-modified silica monolithic adsorbent from Preparation Example 22 was measured into a 100 mL container, and 30 mL of an aqueous solution containing 100 ppm Au or Ag was added. After shaking at 500 rpm for 30 minutes, the mixture was allowed to stand at room temperature for 7 hours. After the reaction was complete, the silica monolithic adsorbent was recovered by filtration. The amount of metal elements in the resulting filtrate was analyzed using an ICP-C luminescence analyzer (HITACHI, PS3520 UVDD), following the same procedure as in Experimental Example 2A, and the Au and Ag adsorption rates were calculated. The Au adsorption rate was >95%, and the Ag adsorption rate was >95%. It should be noted that ">95%" indicates that it exceeds 95% as an analytical guarantee value.

[0302] [Manufacturing Example 23]

[0303] Using a mold for forming cylindrical silica monoliths with an average diameter of 3.0 mm, the same procedures as in Manufacturing Example 21 were followed to produce cylindrical silica monoliths. The resulting silica monoliths had an average diameter of 3.0 mm, a length of 4.8 mm, and an aspect ratio of 1.6. Using the obtained silica monoliths, silica monolith adsorbent materials were produced using the same procedures as in Manufacturing Example 21.

[0304] [Experimental Example 6] Reuse Experiment

[0305] (1) Adsorption treatment

[0306] Measure 2.0 g of the silica monolithic adsorbent obtained in Manufacturing Example 23 into a 100 mL container, and add 40 mL of an aqueous solution containing 100 ppm each of platinum nitrate, palladium nitrate, and rhodium nitrate. Gently shake and let stand at room temperature for 7 hours. After the reaction is complete, recover the silica monolithic adsorbent by filtration. Analyze the metal content of the resulting filtrate using an ICP-C luminescence analyzer (HITACHI PS3520 UVDD), and calculate the platinum, palladium, and rhodium adsorption rates using the same procedure as above.

[0307] (2) Reuse processing

[0308] Following (1) above, the silica monoliths recovered through filtration were washed three times with 10 mL of 1N hydrochloric acid to detach the adsorbed metal species, and then treated with 10 mL of 5 w / w% sodium hydroxide aqueous solution. The treated silica monoliths were then washed with pure water until the pH of the washing solution was near neutral, and then dried under reduced pressure to obtain reusable granules.

[0309] Using the recycled granules, the same adsorption and recycling processes were performed as described above, repeating the recycling process four times. The platinum, palladium, and rhodium adsorption rates, calculated based on the metal content of the filtrate obtained from the five adsorption processes, are shown in Table 9.

[0310] [Table 9]

[0311]

[0312] [Experimental Example 7] Reuse Experiment Based on Solution Flow

[0313] (1) Adsorption treatment

[0314] 3.0 g of silica granular adsorbent material with an average diameter of 4.6 mm obtained in Manufacturing Example 14 was filled into a stainless steel column (20 mm in diameter and 50 mm in length), and connected to a liquid delivery pump via stainless steel piping, thus proceeding in the same manner as in Experimental Example 4. Figure 6 The flow-through adsorption apparatus is shown. After filling the flow path with water by pumping pure water at a rate of 5 mL / min for 2 minutes, an aqueous solution containing 100 ppm each of platinum nitrate, palladium nitrate, and rhodium nitrate is pumped at a rate of 0.5 mL / min. Ten minutes after the start of pumping, the aqueous solution passing through the column is collected in a container. The metal content of the collected aqueous solution is analyzed using an ICP-based luminescence analyzer (HITACHI PS3520 UVDD). The platinum, palladium, and rhodium adsorption rates are calculated using the same procedure as in Example 2A.

[0315] (2) Reuse processing

[0316] Following step (1) above, the adsorbed metal species are detached by washing twice with 30 mL of 12N hydrochloric acid or aqua regia. Then, the adsorbed material is washed twice with 30 mL of pure water and treated with 30 mL of a 0.23 mol / L sodium carbonate aqueous solution. The treated silica monoparticles are then washed with pure water until the pH of the washing liquid is near neutral, followed by vacuum drying to obtain reusable granules. It should be noted that in the above washing and treatment processes, a pump is used to deliver the solutions into the column. Furthermore, the adsorbent material is not recycled; the process is carried out while the column is filled with the material.

[0317] Using the recycled granules, the same adsorption and recycling processes were performed as described above, and the recycling was repeated three times. The platinum, palladium, and rhodium adsorption rates, calculated based on the metal content of the filtrate obtained from the four adsorption processes, are shown in Table 10A (for cases where 12N hydrochloric acid was used) and Table 10B (for cases where aqua regia was used).

[0318] [Table 10A]

[0319]

[0320] [Table 10B]

[0321]

[0322] [Manufacturing Example 24]

[0323] (1) Fabrication of a single silicon dioxide block

[0324] Add 8.67 g of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH), 7.80 g of urea, and 86.7 g of a 6.06% by mass aqueous solution of acetic acid to a 150 mL reaction vessel and stir at room temperature for 10 minutes. Place the reaction vessel in an ice bath and cool the reaction solution while stirring for 15 minutes. Add 44.7 g of tetramethoxysilane to the cooled reaction solution and stir while cooling in an ice bath for 30 minutes. Add a mold to the reaction vessel to form cylindrical silica monoliths with an average diameter of 4.6 mm. Heat the reaction solution in a 30°C bath and then let it stand overnight in a 30°C incubator to prepare a polysiloxane gel.

[0325] Next, the obtained polysiloxane gel was added to another reaction vessel containing 30 mL of 3 mol / L urea solution, and the mixture was heated under reflux for 12 hours. After the reaction was completed, the obtained polysiloxane gel was washed with water and dried in a dryer set to 60°C for 12 hours. After drying, it was calcined at 600°C for 5 hours in air to obtain cylindrical silica monoliths with an average diameter of 4.6 mm. The obtained silica monoliths were cut to adjust the length to 7.4 mm to produce silica monoliths with an aspect ratio of 1.6.

[0326] (2) Determination of specific surface area and mode pore size of mesopores

[0327] The same procedure as in Manufacturing Example 1 was followed to determine the specific surface area and the mode pore size of the mesopores. The results are shown in Table 11A.

[0328] (3) Determination of total pore volume, mode pore size of macropores and porosity

[0329] The same procedure as in Manufacturing Example 1 was followed to determine the total pore volume, the mode pore diameter of the macropores, and the porosity. The results are shown in Table 11A.

[0330] (4) Fabrication of silica monolithic adsorbent material

[0331] 5.0 g of the obtained silica monoliths were added to the reaction vessel, followed by 35 mL of pure water and 3.73 g of 3-aminopropyltrimethoxysilane. The mixture was then heated under reflux at 100 °C for 4 hours. The silica monoliths were separated from the solution by filtration, washed with 500 mL of pure water, and dried to obtain 6.44 g of silica monolith adsorbent material.

[0332] (5) Determination of the amount of nitrogen-containing groups

[0333] The amount of nitrogen-containing groups (-NH2) in the monolithic silica adsorbent material was determined using an oxygen, nitrogen, and hydrogen analyzer (LECO JAPAN Contract Co., Ltd. ONH836). The results are shown in Table 11A.

[0334] [Manufacturing Example 25]

[0335] In the preparation of the silica monolithic adsorbent material, the amount of 3-aminopropyltrimethoxysilane was changed to 5.97 g. Otherwise, the same procedures as in Preparation Example 24 were followed, including the preparation of the silica monoliths, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size and porosity of macropores, preparation of the silica monolithic adsorbent material, and determination of the amount of nitrogen-containing groups (-NH2). The results are shown in Table 11A.

[0336] [Manufacturing Example 26]

[0337] In the preparation of the silica monolithic adsorbent material, 4.63 g of 3-(2-aminoethylamino)propyltrimethoxysilane was used instead of 3.73 g of 3-aminopropyltrimethoxysilane as the silane coupling agent. Otherwise, the same procedures as in Preparation Example 24 were followed, including the preparation of the silica monoliths, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores and porosity, preparation of the silica monolithic adsorbent material, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The measurement results are shown in Table 11A.

[0338] [Manufacturing Example 27]

[0339] In the preparation of the silica monolithic adsorbent material, 5.52 g of 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane was used as the silane coupling agent instead of 3.73 g of 3-aminopropyltrimethoxysilane. Otherwise, the same procedures as in Manufacturing Example 24 were followed, including the preparation of the silica monoliths, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores and porosity, preparation of the silica monolithic adsorbent material, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The measurement results are shown in Table 11A.

[0340] [Manufacturing Example 28]

[0341] The silica monolithic adsorbent material was prepared as follows. Except for the following operations, the silica monoliths were prepared, and the specific surface area, the modal pore size of mesopores, the total pore volume, the modal pore size and porosity of macropores, and the amount of nitrogen-containing groups (-NH2, -NH- and -N<) were measured. The measurement results are shown in Table 11A.

[0342] In manufacturing example 28, the silica monolithic adsorbent material was prepared as follows: 5.0 g of silica monoliths were added to a reaction vessel, followed by the addition of 20 mL of 0.1% acetic acid aqueous solution, 15 mL of ethanol, and 4.92 g of 3-glycidoxypropyltrimethoxysilane. The mixture was then heated under reflux at 100°C for 4 hours. The silica monoliths were separated from the solution by filtration, washed with 500 mL of pure water, and dried. All of the obtained silica monoliths were added to the reaction vessel, along with 3.33 g of polyethyleneimine (weight average molecular weight: 600) and 35 mL of pure water. The mixture was then heated at 80°C for 4 hours. The silica monoliths were separated from the solution by filtration, washed with 500 mL of pure water, and dried to obtain 7.35 g of silica monolithic adsorbent material.

[0343] [Manufacturing Example 29]

[0344] In the fabrication of the silica monolith, the amount of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH) was changed to 8.25 g. Otherwise, the same procedures as in Manufacturing Example 26 were followed, including the fabrication of the silica monolith, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores, porosity, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The results are shown in Table 11A.

[0345] [Manufacturing Example 30]

[0346] In the fabrication of the silica monolith, the amount of polyethylene glycol 10000 (manufactured by SIGMA-ALDRICH) was changed to 9.08 g. Otherwise, the same procedures as in Manufacturing Example 26 were followed, including the fabrication of the silica monolith, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores, porosity, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The results are shown in Table 11B.

[0347] [Manufacturing Example 31]

[0348] In the fabrication of the silica monolith, the reflux time in 3 mol / L urea water was changed to 5 hours. Otherwise, the same procedures were followed as in Manufacturing Example 26, including the fabrication of the silica monolith, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores, porosity, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The results are shown in Table 11B.

[0349] [Manufacturing Example 32]

[0350] In the fabrication of the silica monolith, the heating and reflux time in 3 mol / L urea water was changed to 24 hours. Otherwise, the same procedures were followed as in Manufacturing Example 26, including the fabrication of the silica monolith, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size of macropores, porosity, and determination of the amount of nitrogen-containing groups (-NH2 and -NH-). The results are shown in Table 11B.

[0351] [Experimental Example 8A] Metal Adsorption Test Based on Solution Immersion

[0352] Two 2.5 g samples of each silica monolithic adsorbent obtained in Examples 24-32 were immersed in 50 mL of an aqueous solution (containing 10 ppm of each of the metal elements Au, Ir, Os, Pd, Pt, Rh, and Ru) obtained by diluting TraceCERT Transition metal mix 3 for ICP solution (manufactured by SIGMA-ALDRICH) 10 times with pure water, and allowed to stand at room temperature for 24 hours. After the reaction was completed, the silica monolithic adsorbent was separated by filtration, and the amount of metal elements contained in the filtrate was analyzed using an ICP luminescence analyzer (manufactured by HITACHI, PS3520UVDD). For each metal element, the percentage of the amount of metal element adsorbed by the silica monolithic adsorbent relative to the amount of metal element initially contained in the aqueous solution (hereinafter referred to as "adsorption rate") was calculated. The total adsorption rate (%) of all metal elements is shown in Tables 11A and 11B.

[0353] [Experimental Example 8B] Metal Adsorption Test Based on Solution Immersion

[0354] The silica monoliths obtained in Examples 24-32 were pulverized in a mortar until the particle size was 300 μm or more and 1000 μm or less. 300 mg of the pulverized adsorbent was immersed in 30 mL of an aqueous solution (containing 10 ppm of each of the metal elements Au, Ir, Os, Pd, Pt, Rh, and Ru) obtained by diluting TraceCERT Transitionmetal mix 3 for ICP solution (manufactured by SIGMA-ALDRICH) 10 times with pure water, and stirred at 25°C for 30 minutes. After the reaction, the silica monoliths were separated by filtration, and the amount of metal elements in the resulting filtrate was analyzed using an ICP luminescence analyzer (HITACHI, PS3520 UVDD). For each metal element, the percentage of the amount of metal element adsorbed by the silica monoliths relative to the amount of metal element initially contained in the aqueous solution (hereinafter referred to as "adsorption rate") was calculated. The total adsorption rate (%) of all metal elements is shown in Tables 11A and 11B.

[0355] [Experimental Example 8C] Metal Adsorption Test Based on Solution Immersion

[0356] The silica monoliths obtained in Examples 24-32 were pulverized in a mortar until the particle size was 38 μm or larger and 75 μm or smaller. 30 mg of the pulverized adsorbent was immersed in 30 mL of an aqueous solution (containing 50 ppm Au) obtained by diluting the gold standard stock solution (containing 1000 ppm Au) (manufactured by Kanto Chemical Co., Ltd.) 20 times with pure water, and stirred at 25°C for 5 or 15 minutes. After the reaction, the silica monoliths were separated by filtration, and the amount of gold in the resulting filtrate was analyzed using an ICP-based luminescence analyzer (HITACHI, PS3520 UVDD) to calculate the amount of gold adsorbed. The adsorption rate (mg / min) was calculated by dividing the amount of gold adsorbed (mg) by the adsorption time (5 or 15 minutes). The calculated adsorption rates are shown in Tables 11A and 11B.

[0357] [Comparative Example 1]

[0358] In the preparation of the silica monolithic adsorbent material, the amount of 3-aminopropyltrimethoxysilane was changed to 0.75 g. Otherwise, the same procedure as in Preparation Example 24 was followed to prepare the silica monoliths, determine the specific surface area, the modal pore size of mesopores, the total pore volume, the modal pore size and porosity of macropores, and the amount of nitrogen-containing groups (-NH2). The results are shown in Table 11B.

[0359] For the silica monolithic adsorbent material obtained in Comparative Example 1, metal adsorption tests were conducted in the same manner as in Experimental Examples 8A to 8C. The results are shown in Table 11B.

[0360] [Comparative Example 2]

[0361] In the preparation of the silica monolithic adsorbent material, the amount of 3-aminopropyltrimethoxysilane was changed to 1.49 g. Otherwise, the same procedure as in Preparation Example 24 was followed to prepare the silica monoliths, determine the specific surface area, the modal pore size of mesopores, the total pore volume, the modal pore size and porosity of macropores, and the amount of nitrogen-containing groups (-NH2). The results are shown in Table 11B.

[0362] For the silica monolithic adsorbent material obtained in Comparative Example 2, metal adsorption tests were conducted in the same manner as in Experimental Examples 8A to 8C. The results are shown in Table 11B.

[0363] [Comparative Example 3]

[0364] In the fabrication of the silica monolithic adsorbent material, the heating temperature in the presence of polyethyleneimine was changed to 100°C. Otherwise, the same procedures as in Manufacturing Example 28 were followed, including the fabrication of the silica monoliths, determination of specific surface area, modal pore size of mesopores, total pore volume, modal pore size and porosity of macropores, and determination of the amount of nitrogen-containing groups (-NH2, -NH-, and -N<). The measurement results are shown in Table 11B.

[0365] For the silica monolithic adsorbent material obtained in Comparative Example 3, metal adsorption tests were conducted in the same manner as in Experimental Examples 8A to 8C. The results are shown in Table 11B.

[0366] [Comparative Example 4]

[0367] Commercially available amine-modified silica 3-Aminopropyl Silica Gel (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of silica monolithic adsorbent material. Otherwise, the same procedure was followed as in Test Examples 8A to 8C for metal adsorption tests. The results are shown in Table 11C.

[0368] [Comparative Example 5]

[0369] Commercially available amine-modified silica Wakogel 50NH2 (manufactured by Fujifilm and Koko Pure Chemical Industries, Ltd.) was used instead of silica monolithic adsorbent material. Otherwise, the same procedure was followed as in Test Examples 8A to 8C for metal adsorption tests. The results are shown in Table 11C.

[0370] [Comparative Example 6]

[0371] Commercially available amine-modified silica R-Cat-Sil AP (manufactured by Kanto Chemical Co., Ltd.) was used instead of the silica monolithic adsorbent material. Otherwise, the metal adsorption tests were performed in the same manner as in Test Examples 8A to 8C. The results are shown in Table 11C.

[0372] [Comparative Example 7]

[0373] Commercially available aminomethyl polystyrene ion exchange resin (manufactured by SIGMA-ALDRICH) was used instead of silica monolithic adsorbent material. Otherwise, the metal adsorption tests were performed in the same manner as in Test Examples 8A to 8C. The results are shown in Table 11C.

[0374] [Table 11A]

[0375]

[0376] [Table 11B]

[0377]

[0378] [Table 11C]

[0379]

[0380] From the perspective of prioritizing recovery speed when applying adsorbent materials to practical applications, in this invention, adsorption speed is prioritized over adsorption rate for high performance. Tables 11A, 11B, and 11C clearly show that the adsorption rates of Manufacturing Examples 24-32 are equal to or higher than those of Comparative Examples 1, 2, and 4-7, and the adsorption rates of Manufacturing Examples 24-32 exceed those of Comparative Examples 1, 2, and 4-7. Furthermore, it is known that in Comparative Example 3, which contains an excessive amount of nitrogen-containing groups, the adsorption rate (Test Example 8B) and adsorption rate are equal to those of Manufacturing Examples 24-32, but the adsorption rate (Test Example 8A) is lower than that of Manufacturing Examples 24-32. This can be attributed to the increased hydrophobicity of the silica monolith due to the increased amount of functional groups, making it difficult for solutions containing metals to reach the pores and hindering the effective utilization of the introduced functional groups; therefore, it is unsuitable for practical application.

[0381] Explanation of reference numerals in the attached figures

[0382] 1… Columnar body

[0383] 2… Ceramic skeleton

[0384] 3…large hole

[0385] 4…Mesoporous

[0386] 60… Flow Adsorption Device

[0387] 61… Stainless steel column

[0388] 62… Stainless steel piping

[0389] 63…Liquid delivery pump

[0390] 64…Recycling Containers

Claims

1. A method for recovering metals and / or metal ions, comprising the following steps: (1) The process of preparing a solution containing metals and / or metal ions; (2) A step of preparing an adsorbent material, wherein the adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, the surface of the ceramic framework is modified with functional groups capable of adsorbing metals and / or metal ions, the modal pore size of the macropores before modification with the functional groups is 0.20 μm or more and 4.0 μm or less, the modal pore size of the mesopores before modification with the functional groups is 2.0 nm or more and 50 nm or less, the functional groups capable of adsorbing metals and / or metal ions include groups containing nitrogen atoms, the nitrogen-containing groups being selected from at least one of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, and hypoazine groups, the surface of the ceramic framework is modified by the nitrogen-containing groups by fixing an amine compound having the nitrogen-containing groups onto the surface of the ceramic framework, the amine compound being selected from formula A:R a -R d -Si(-R b ) n (-R) c ) 3-n The monoamine shown, formula B:R a -R d -NH-R e -Si(-R b ) n (-R) c ) 3-n The diamine shown, formula C:R a -R d -NH-R e -NH-R f -Si(-R b ) n (-R) c ) 3-n The formulas A, B, and C contain at least one of the following: triamine, polyalkylimide with a weight average molecular weight of 146 or more and 30,000 or less, polyvinylamine with a weight average molecular weight of 174 or more and 25,000 or less, and polyallylamine with a weight average molecular weight of 230 or more and 150,000 or less. In formulas A, B, and C, R... a Represents primary, secondary, tertiary, or quaternary ammonium groups, with n R groups. b Each independently represents ethyl, propyl, or butyl, (3-n) R c Each independently represents an alkoxy or halogen group having 1 or more but less than 10 carbon atoms, R d R e and R f Each of the groups independently represents ethylene, propyleneene, butylene, arylene with 4 or more and 14 or less carbon atoms, or combinations thereof, where n represents an integer from 0 to 2, and the amount of the nitrogen-containing group is based on the mass of the adsorbent material and is 1.5 mmol / g or more and 5.4 mmol / g or less. (3) The process of bringing the solution into contact with the adsorbent material; (4) A process of contacting the adsorbent material supplied to process (3) with an acidic solution; as well as (5) A process for recovering the metal and / or the metal ions from the acidic solution supplied to process (4).

2. The method according to claim 1, R a The secondary amino group is represented by the formula -NHR 1 express, R a The tertiary amino group is represented by the formula -NR 1 R 2 express, R a The quaternary ammonium group is represented by the formula -N + R 1 R 2 R 3 express, R 1 R 2 and R 3 Each can be used independently to represent an alkyl group having 1 or more but less than 10 carbon atoms.

3. The method according to claim 1, wherein the amine compound is selected from... Formula A: R a -R d -Si(-R b ) n (-R) c ) 3-n The monoamine shown Formula B: R a -R d -NH-R e -Si(-R b ) n (-R) c ) 3-n The diamine shown Formula C: R a -R d -NH-R e -NH-R f -Si(-R b ) n (-R) c ) 3-n The triamine and Polyalkylimides with a weight average molecular weight of 146 or higher and 30,000 or lower At least one of them.

4. The method according to claim 3, R a The secondary amino group is represented by the formula -NHR 1 express, R a The tertiary amino group is represented by the formula -NR 1 R 2 express, R a The quaternary ammonium group is represented by the formula -N + R 1 R 2 R 3 express, R 1 R 2 and R 3 Each can be used independently to represent an alkyl group having 1 or more but less than 10 carbon atoms.

5. A method for regenerating the adsorbent material used in any one of claims 1 to 4, comprising a step of contacting the adsorbent material supplied to step (4) with an alkaline solution.

6. The method according to any one of claims 1 to 5, wherein, In the adsorbent material, the ratio of the mode pore size of the macropores before modification with the functional groups to the mode pore size of the mesopores before modification with the functional groups is 15 or more and 200 or less.

7. The method according to any one of claims 1 to 5, wherein, The ceramic framework contains elements selected from silicon, aluminum, tin, cerium, titanium, and zirconium.

8. The method according to any one of claims 1 to 5, wherein, The metal is a transition metal, and the metal ion is a transition metal ion.

9. The method according to claim 8, wherein, The transition metal is a noble metal, and the transition metal ion is a noble metal ion.

10. The method according to any one of claims 1 to 5, wherein, The adsorbent material is a columnar body with an average diameter of 1.5 mm or more and 20 mm or less.

11. The method according to claim 10, wherein, The aspect ratio of the columnar body is 0.70 or higher.

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