Method for producing adsorbent material and method for recovering target substance

Abstract

The present invention aims to provide a method for manufacturing (regenerating) an adsorbent material or recovering a target substance by performing a desorption treatment on the target substance after adsorbing it onto the adsorbent material. This method enables the removal of a sufficient amount of the target substance without the use of aqua regia during the desorption treatment and prevents a decrease in the adsorption performance of the adsorbent material after the desorption treatment. To solve this problem, a method for manufacturing an adsorbent material or recovering a target substance is provided, the method comprising the following steps: step (1), preparing a second adsorbent material obtained by contacting a first adsorbent material with a liquid containing the target substance, wherein the first adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, and the surface of the ceramic framework is modified with functional groups capable of adsorbing the target substance; and step (2), removing the target substance from the second adsorbent material by contacting it with an acidic solution other than aqua regia to obtain a third adsorbent material or the target substance.

Description

Technical Field

[0001] This invention relates to a method for manufacturing adsorbent materials and a method for recovering target substances. Background Technology

[0002] From the perspectives of carbon neutrality and the SDGs, technologies related to the reuse or recycling of target substances have attracted attention. Examples of such technologies include the recovery of metals or metal ions contained in liquids. As a metal or metal ion recovery technology, adsorbent materials with surfaces modified with functional groups are known (e.g., Patent Documents 1-3). These adsorbent materials can be reused after the adsorbed metals or metal ions are removed.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 3-158426

[0006] Patent Document 2: Japanese Patent Application Publication No. 2016-11456

[0007] Patent Document 3: International Publication No. 2017 / 002871 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The inventors have discovered that when an adsorbent is subjected to a process to remove a target substance selected from the group consisting of metals, metal ions, metalloids, and metalloid ions, the adsorption performance of the adsorbent after removal treatment may decrease compared to that before removal treatment, depending on the conditions of the removal treatment. Furthermore, the inventors have found that this tendency is particularly pronounced when the removal treatment is performed under harsh conditions (e.g., using aqua regia) with the aim of increasing the amount of target substance removed.

[0010] The reduced adsorption performance of adsorbent materials after desorption treatment compared to before desorption treatment is a problem when reusing adsorbent materials. Therefore, the object of the present invention is to provide a method for manufacturing (regenerating) adsorbent materials or recovering target substances by subjecting adsorbent materials to a desorption treatment of target substances after adsorbing them from the group consisting of metals, metal ions, metalloids, and metalloid ions, thereby enabling the desorption of a sufficient amount of target substances without the use of aqua regia in the desorption treatment and preventing the reduction in adsorption performance of the adsorbent materials after desorption treatment.

[0011] Solution for solving the problem

[0012] To address the aforementioned issues, the present invention provides the following method.

[0013] [1] A method for manufacturing an adsorbent material, comprising the following steps:

[0014] Step (1A): Preparing a second adsorbent material, which is obtained by contacting a first adsorbent material with a liquid containing a target substance. The first 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 the target substance selected from the group consisting of metals, metal ions, metalloids, and metalloid ions.

[0015] Step (2A) involves contacting the second adsorbent material with an acidic solution other than aqua regia to detach the target substance from the second adsorbent material, thereby obtaining a third adsorbent material.

[0016] The percentage of the adsorption amount of the target substance in the second adsorbent material prepared in step (1A) relative to the saturated adsorption amount of the target substance in the first adsorbent material is 50% or more.

[0017] The percentage of the amount of the target substance removed in step (2A) relative to the amount of the target substance adsorbed in the second adsorbent material prepared in step (1A) is 70% or more.

[0018] [2] According to the manufacturing method described in [1], the contact treatment in the step (2A) is performed at a temperature below 90°C.

[0019] [3] The manufacturing method according to [1] or [2], wherein the acidic solution comprises at least one selected from the group consisting of inorganic acids and ammonium salts.

[0020] [4] The manufacturing method according to any one of [1] to [3], wherein the total concentration of the inorganic acid and ammonium salt contained in the acidic solution is 0.1 mol / L or more and 13 mol / L or less.

[0021] [5] The manufacturing method according to any one of [1] to [4], wherein the acidic solution comprises at least one selected from the group consisting of hydrochloric acid, nitric acid and ammonium chloride.

[0022] [6] The manufacturing method according to any one of [1] to [5], wherein the functional group comprises at least one selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium group, imino, hyponitro group, nitrogen-containing heterocyclic group, thiol group, sulfonyl group, phosphonic acid group and carboxyl group.

[0023] [7] The manufacturing method according to any one of [1] to [6], wherein the ceramic skeleton comprises at least one selected from the group consisting of silicon, aluminum, tin, cerium, titanium and zirconium.

[0024] [8] The manufacturing method according to any one of [1] to [7], wherein the object material is selected from the group consisting of transition metals containing rare earth metals, metals and metalloids of groups 13 to 16, transition metal ions containing rare earth metal ions, and metal ions and metalloids of groups 13 to 16.

[0025] [9] A method for recycling a target substance, comprising the following steps:

[0026] Step (1B): Preparing a second adsorbent material, obtained by contacting a first adsorbent material with a liquid containing the target substance, wherein the first adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, and the surface of the ceramic framework is modified with functional groups capable of adsorbing the target substance selected from the group consisting of metals, metal ions, metalloids, and metalloid ions; and

[0027] Step (2B) involves contacting the second adsorbent material with an acidic solution other than aqua regia to detach the target substance from the second adsorbent material, thereby obtaining the target substance.

[0028] The percentage of the adsorption amount of the target substance in the second adsorbent material prepared in step (1B) relative to the saturated adsorption amount of the target substance in the first adsorbent material is 50% or more.

[0029] The percentage of the amount of the target substance removed in step (2B) relative to the amount of the target substance adsorbed in the second adsorbent material prepared in step (1B) is 70% or more.

[0030] The effects of the invention

[0031] According to the present invention, a method is provided in which an adsorbent material is subjected to a desorption treatment after adsorbing a target substance selected from the group consisting of metals, metal ions, metal quasi-metals and metal quasi-metal ions, thereby manufacturing (regenerating) the adsorbent material or recovering the target substance. This method can desorb a sufficient amount of the target substance without using aqua regia in the desorption treatment and can prevent the adsorption performance of the adsorbent material after the desorption treatment from decreasing.

[0032] Even when the method of the present invention is repeatedly applied to the adsorbent material to manufacture (regenerate) the adsorbent material or to recover the target substance, a sufficient amount of the target substance can be removed without the use of aqua regia during the removal process, and the desorption performance of the adsorbent material after the removal process can be prevented from decreasing. Therefore, the method of the present invention is particularly useful when repeatedly manufacturing (regenerating) the adsorbent material or repeatedly recovering the target substance. Attached Figure Description

[0033] Figure 1 This is an enlarged view of a portion of the surface of an adsorbent material according to one embodiment.

[0034] Figure 2 This is a schematic diagram of the flow adsorption device used in the embodiments and comparative examples. Detailed Implementation

[0035] Glossary of Terms

[0036] The following describes the terminology used in this specification. Unless otherwise specified, the following description applies mutatis mutandis.

[0037] <halogen atom>

[0038] Halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0039] <alkyl>

[0040] The alkyl group has, for example, 1 to 20 carbon atoms, preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 5, and still more preferably 1 to 4. The alkyl group can be straight-chain or branched. Examples of alkyl groups include methyl, ethyl, propyl, and butyl.

[0041] <Aryl>

[0042] The aryl group is, for example, a monocyclic or polycyclic aromatic hydrocarbon cyclic group (e.g., bicyclic or tricyclic). The aryl group has, for example, 6 to 14 carbon atoms, preferably 6 to 10. The polycyclic form can be a fused ring. Examples of aryl groups include phenyl and naphthyl groups.

[0043] <Arylalkyl>

[0044] 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.

[0045] <alkylaryl>

[0046] 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.

[0047] <alkoxy>

[0048] An alkoxy group is a group represented by the formula: -O-alkyl, as explained above regarding alkyl groups.

[0049] <alkylene>

[0050] Alkylenes are divalent functional groups formed by removing one hydrogen atom from an alkyl group, as explained above regarding alkyl groups. Examples of alkylenes include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene.

[0051] <Aspartic>

[0052] A arylene is a divalent functional group formed by removing one hydrogen atom from an aryl group, as explained above regarding aryl groups. Examples of arylene groups include phenylene, pentylene, indenyl, naphthyl, azulene, phenenenyl, and biphenylene.

[0053] <One or more substituents>

[0054] One or more substituents refers to preferably one to three substituents, more preferably one or two substituents. Each or more substituents can be independently selected from, for example, hydroxyl, halogen atom, thiol group, carboxyl group, phosphate group, phosphonic acid group, sulfonyl group, ketone group, alkoxy group, oxo group, etc.

[0055] <Object Material>

[0056] The target substances include metals, metal ions, metalloids, and metalloid ions.

[0057] Metals and metalloids include transition metals and metals and metalloids of groups 13–16. Metal ions and metalloids include transition metal ions (including rare earth metal ions) and metal ions and metalloids of groups 13–16.

[0058] Transition metals include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Zn, Cd, Hg, and rare earth metals.

[0059] Rare earth metals include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0060] Metals and metalloids in groups 13-16 include B, Al, Si, Ga, Ge, As, Se, In, Sn, Sb, Te, Tl, Pb, Bi, Po, and At. Among them, B, Si, Ge, As, Se, Po, At, Sb, and Te are metalloids.

[0061] From the perspective of the demand for adsorption and recovery, the target substance is preferably selected from noble metals and noble metal ions such as Pt, Pd, Rh, Ru, Ir, Os, Au, Ag, Re, and their ions, more preferably selected from Pt, Pd, Rh, Ru, Ir, Os, Au and their ions, and even more preferably selected from Pt, Pd, Rh, Ir, Au and their ions.

[0062] Examples of metals and metalloids adsorbed onto functional groups include metal and metalloid nanoparticles. Metals adsorbed onto functional groups may or may not have ligands. Similarly, metal ions and metalloids adsorbed onto functional groups may or may not have ligands.

[0063] <Functional groups capable of adsorbing the target substance (sometimes referred to as "adsorbent functional groups" in this specification).>

[0064] Adsorption functional groups can adsorb one type of target substance or two or more target substances.

[0065] The adsorption functional group is preferably a functional group comprising at least one selected from the group consisting of a nitrogen-containing group, a thiol group, a sulfonyl group, a phosphate group, a phosphonic acid group, a carboxyl group, a hydroxyl group, and a ketone group; more preferably, a functional group comprising at least one selected from the group consisting of a nitrogen-containing group, a thiol group, a sulfonyl group, a phosphonic acid group, and a carboxyl group; and even more preferably, a functional group comprising at least one nitrogen-containing group. The adsorption functional group can be a functional group composed of at least one type of nitrogen-containing group.

[0066] The nitrogen-containing group is preferably a functional group selected from the group consisting of at least one of primary amine, secondary amine, tertiary amine, quaternary ammonium group, imino, hypoazine group and nitrogen-containing heterocyclic group, more preferably a functional group selected from the group consisting of primary amine, secondary amine, tertiary amine, quaternary ammonium group, imino and hypoazine group. The nitrogen-containing group can be a functional group composed of at least one of the above-mentioned groups.

[0067] Primary amines are represented by the formula: -NH2. Secondary amines are represented by the formula: -NHR 1 It is represented by the formula: -NR 1 R 2 It is indicated by the formula: -N + R1 R 2 R 3 Indicates. R 1 R 2 and R 3 Each amino group can be, for example, an alkyl group having one or more substituents, an aryl group having one or more substituents, an arylalkyl group having one or more substituents, or an alkylaryl group having one or more substituents. The secondary and tertiary amino groups can be aliphatic or aromatic amino groups, preferably aliphatic amino groups. Examples of aliphatic amino groups include R... 1 For secondary amino groups of alkyl groups that can have more than one substituent, R 1 and R 2 Both of these are tertiary amino groups of alkyl groups that can have more than one substituent. Examples of aromatic amino groups include R... 1 It can be an aryl group having one or more substituents, an arylalkyl group having one or more substituents, or an alkylaryl group having one or more substituents, a secondary amino group, R 1 and R 2 At least one of them is an aryl group that may have one or more substituents, an arylalkyl group that may have one or more substituents, or a tertiaryl group that may have one or more substituents, such as an alkylaryl group. The quaternary ammonium group may 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 an alkyl group having one or more substituents, such as a quaternary ammonium group. Examples of aromatic ammonium groups include R... 1 R 2 and R 3 At least one of them is an aryl group that may have one or more substituents, an arylalkyl group that may have one or more substituents, or a quaternaryl group that may have one or more substituents.

[0068] 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).

[0069] 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, as well as aromatic amino groups such as N,N-diphenylamino.

[0070] Examples of quaternary ammonium groups include trimethylammonium, triethylammonium, and tributylammonium trialkylammonium groups. Examples of counterions to the nitrogen atom constituting the quaternary ammonium group include chloride ions, bromide ions, and hydroxide ions.

[0071] 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). Secondary amines (-NHR) 1 In this compound, the -NH- can be equivalent to an imino group, and the secondary amino group is preferably a terminal group. That is, the secondary amino group (-NHR) 1 R in ) 1 It may have at least one functional group selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and nitrogen-containing heterocyclic group, but preferably does not have one.

[0072] 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). In the former case, the hypoazine group forms a cyano group (-CN) with one carbon atom. Tertiary amines (-NR) 1 R 2 In this group, -N can be equivalent to 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 Each may have at least one functional group selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and nitrogen-containing heterocyclic group, but preferably does not have one.

[0073] A nitrogen-containing heterocyclic group is a monovalent group comprising at least one (e.g., one, two, or three) nitrogen atoms as cyclic atoms. In addition to comprising at least one nitrogen atom, the nitrogen-containing heterocyclic group may also comprise one or more (e.g., one, two, or three) heteroatoms selected from the group consisting of 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 may be an aromatic heterocyclic group or an aliphatic heterocyclic group). The nitrogen-containing heterocyclic group may have one or more substituents.

[0074] 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 nitrogen-containing heterocyclic groups 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 nitrogen-containing heterocyclic groups may fused with a benzene ring to form polycyclic (e.g., bicyclic or tricyclic) nitrogen-containing heterocyclic groups. Examples include indole, isoindole, indazole, benzimidazolyl, benzotriazolyl, oxazolopyrimidinyl, thiazopyrimidinyl, pyrrolopyrimidinyl, pyrrolopyrimidinyl, imidazopyrimidinyl, purine, quinolinyl, isoquinolinyl, boralinyl, phthalazinyl, quinazolinyl, quinoxalinyl, and naphthidyl.

[0075] The linking bond of a nitrogen-containing heterocyclic group can be formed by any cyclic atom. The linking bond of a nitrogen-containing heterocyclic group is usually formed by a carbon atom or a nitrogen atom. When the linking bond of a nitrogen-containing heterocyclic group is formed by a nitrogen atom, the nitrogen-containing heterocyclic group is equivalent to a 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.

[0076] Examples of substances suitable for adsorption using primary amine, secondary amine, tertiary amine, quaternary ammonium group, imine, hyponitro group and nitrogen-containing heterocyclic group include Co, Cr, Cu, Fe, Ni, Os, Pd, Pt, Rh, Ru, Au, Ir, W, Zn, V, Mn, Re, etc.

[0077] Examples of substances suitable for adsorption using thiol groups include Ag, Co, Cu, Fe, Ir, Ni, Os, Pd, Au, Pt, Rh, Ru, Sc, Zn, and Re.

[0078] Examples of substances suitable for adsorption using sulfonyl groups include Cd, Cr, Pb, Zn, Al, Cu, Mn, Sn, Fe, Co, Ni, Ag, and Bi.

[0079] Examples of substances suitable for adsorption using phosphate groups include In, Al, Bi, Pb, Au, Ir, Pd, Pt, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, and Sn.

[0080] Examples of substances suitable for adsorption using phosphonic acid groups include In, Al, Bi, Pb, Au, Ir, Pd, Pt, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, and Sn.

[0081] Examples of substances suitable for adsorption using carboxyl groups include Co, Cr, Cu, Fe, Ir, Ni, Os, Pd, Rh, Ru, Sc, Zn, V, Mn, and Re.

[0082] <First Adsorbent Material>

[0083] The first adsorbent material has a porous body with a co-continuous structure formed by a ceramic framework containing mesopores and macropores, the surface of which is modified with adsorbent functional groups.

[0084] <Morphology and Shape of Porous Materials>

[0085] The morphology of porous bodies is not particularly limited. Examples of porous bodies include granules, blocks, and shaped bodies. Furthermore, the shape of porous bodies is not particularly limited. Examples of porous bodies include columnar, spherical (e.g., spherical, ellipsoidal), needle-like, scaly (flake-like), polyhedral, flat, fragmented, and blocky shapes. Examples of columnar shapes include cylindrical, elliptical, and polygonal prisms (e.g., square, hexagonal, octagonal prisms). A columnar shape can also be a cylindrical, elliptical, or polygonal shape with localized defects.

[0086] When the porous body is in the form of particles, the particle size is, for example, 0.5 μm or more and 7.0 mm or less. Particle size refers to the equivalent circle diameter, that is, the diameter of the circle in an observed image of the particle (e.g., a SEM image) that assumes an area equal to the area of ​​the particle. The particle size can be adjusted, for example, by grading.

[0087] When the porous body is cylindrical, its length is, for example, 1.0 mm or more and 500 mm or less, and its diameter is, for example, 1.5 mm or more and 20 mm or less. Length refers to the dimension along the direction in which the cylindrical body extends. Diameter refers to the diameter of the end face along the direction in which the cylindrical body extends. If the end face is circular, the diameter refers to the diameter of the circle. If the end face is a shape other than circular, the diameter refers to the diameter of the circle circumscribed around the end face.

[0088] <Structure of the porous body before modification>

[0089] The following is for reference Figure 1 The structure of the porous body before modification with adsorption functional groups is described. Figure 1 This is an enlarged view of a portion of the surface of a porous body in one embodiment.

[0090] like Figure 1 As shown, the porous body has a co-continuous structure formed by a ceramic framework 1 containing mesopores 3 and macropores 2.

[0091] In the porous body, the ceramic framework 1 and macropores 2 each possess a continuous three-dimensional network structure and are intertwined, thus forming a co-continuous structure of the ceramic framework 1 and macropores 2. This co-continuous structure of the porous body can be confirmed by scanning electron microscopy (SEM) observation of the surface or cross-section of the porous body. Due to this co-continuous structure, the porous body can efficiently adsorb and desorb target substances, thereby enabling the detachment of a sufficient amount of target substances without the use of aqua regia and preventing a decrease in the adsorption performance of the adsorbent material after desorption treatment.

[0092] From the viewpoint of improving adsorption-desorption performance, the mode pore size of macropore 2 is preferably 0.20 μm or more, more preferably 0.40 μm or more, and even more preferably 0.60 μm or more. From this viewpoint, the mode pore size of macropore 2 is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less. These upper limits can be combined with any of the lower limits mentioned above.

[0093] "The mode pore size of macropore 2" as described in the examples below refers to the mode pore size of the macropore measured by mercury intrusion porosimetry in the range of 50 nm to 500 μm.

[0094] From the viewpoint of improving adsorption and desorption performance, the mode pore size of mesopore 3 is preferably 2.0 nm or more, more preferably 5.0 nm or more, and even more preferably 10.0 nm or more. From this viewpoint, the mode pore size of mesopore 3 is preferably 50.0 nm or less, more preferably 40.0 nm or less, and even more preferably 35.0 nm or less. These upper limits can be combined with any of the lower limits mentioned above.

[0095] "The mode pore size of mesopore 3" as described in the examples described later refers to the mode pore size of the mesopore determined by the BJH method using a nitrogen adsorption-desorption isotherm.

[0096] From the viewpoint of improving adsorption-desorption performance, the ratio of the mode pore size of the macropore 2 to the mode pore size of the mesopore 3 is preferably 15 or more, more preferably 20 or more, even more preferably 30 or more, and even more preferably 33 or more. From this viewpoint, this ratio is preferably 300 or less, more preferably 200 or less, even more preferably 150 or less, and even more preferably 100 or less. These upper limits can be combined with any of the lower limits mentioned above.

[0097] From the perspective of improving adsorption-desorption performance, the optimal specific surface area of ​​the porous body, determined by the BET method based on the nitrogen adsorption-desorption isotherm, is 100 m². 2 / g or 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 porous body. The method for determining the specific surface area based on the BET method using nitrogen adsorption-desorption isotherms is described in the examples below.

[0098] From the viewpoint of improving adsorption-desorption performance, the total pore volume of the porous material, as determined 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 2.5 mL / g or more and 3.5 mL / g or less. The method for determining the total pore volume using mercury porosimetry is described in the examples below.

[0099] From the viewpoint of improving adsorption-desorption performance, the porosity of the porous body, as determined 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 75% or more and 85% or less. The method for determining porosity based on mercury porosimetry is described in the examples below.

[0100] <Porous Materials>

[0101] The ceramic that forms the ceramic framework is, for example, an oxide ceramic containing elements selected from the group consisting of quasi-metallic elements and metallic elements. The ceramic framework may contain one element selected from the group consisting of quasi-metallic elements and metallic elements, or it may contain two or more elements selected from the above group.

[0102] Silicon can be cited as an example of a metalloid element. Silicon dioxide (SiO2) can be cited as an example of a silicon-containing oxide ceramic.

[0103] As metallic elements, examples include zinc, cerium, titanium, zirconium, vanadium, chromium, iron, cobalt, nickel, palladium, platinum, copper, silver, and gold, in addition to aluminum and tin. From the viewpoint of easily creating porous bodies, the preferred metallic elements are those consisting of aluminum, tin, cerium, titanium, and zirconium. Examples of oxide ceramics containing aluminum, tin, cerium, titanium, or zirconium include alumina (Al₂O₃), tin oxide (SnO₂), cerium oxide (CeO₂), titanium dioxide (TiO₂), and zirconium oxide (ZrO₂).

[0104] In addition to silicon, aluminum, tin or transition metal elements, oxide ceramics may also contain elements selected from the group consisting of alkali metal elements such as lithium and sodium, alkaline earth metal elements such as magnesium and calcium, and rare earth elements such as lanthanum, scandium, yttrium and gadolinium.

[0105] <Methods for manufacturing porous materials>

[0106] Porous bodies can be manufactured, for example, by the method described in International Publication No. 2022 / 163834, specifically by a method including the following steps:

[0107] Step (a) involves manufacturing polyoxometalate gels via a sol-gel method;

[0108] Step (b) involves forming pores in the framework of the polyoxometalate gel manufactured in step (a); and

[0109] Step (c) involves cleaning and / or drying the polyoxometalate gel supplied to step (b) as needed, followed by firing to produce a ceramic block (monolithic) (porous body).

[0110] In one embodiment, the ceramic bulk body is preferably a silica bulk body. The silica bulk body has a co-continuous structure formed by a silica framework containing mesopores and macropores.

[0111] In another embodiment, the ceramic bulk can be a bulk of alumina, tin oxide, cerium oxide, titanium dioxide, or zirconium oxide. Similarly, in this case, the bulk has a co-continuous structure formed by a framework of mesoporous alumina, tin oxide, cerium oxide, titanium dioxide, or zirconium oxide and macropores.

[0112] The manufactured ceramic blocks can be shaped and used as adsorbent materials (e.g., adsorbent materials with columnar shapes), or they can be manufactured using molds or similar methods, directly or as needed, and used as adsorbent materials (e.g., adsorbent materials with columnar shapes). For example, in a gel manufacturing process, shaped 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 shaped ceramic blocks is smaller than the average diameter of the mold.

[0113] The manufactured ceramic blocks can also be pulverized and used as adsorbent materials. Pulverization can be carried out using conventional methods. For example, pulverization can be performed using a mortar and pestle, 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 7.0 mm or less, more preferably 0.5 μm or more and 5.0 mm or less, even more preferably 2.0 μm or more and 4.0 mm or less, and even more preferably 5.0 μm or more and 3.0 mm or less. It should be noted that "particle size" refers to the equivalent circle diameter, that is, the diameter of the circle in the observed image (e.g., SEM image) of the pulverized adsorbent material, assuming a circle with an area equal to the area of ​​the pulverized adsorbent material.

[0114] <Surface Modification>

[0115] In the first adsorbent material, the surface of the ceramic framework is modified with adsorption functional groups. The surface of the ceramic framework can be modified with one type of adsorption functional group or with two or more types of adsorption functional groups. The adsorption functional groups can be directly bonded to the surface of the ceramic framework or bonded to the surface of the ceramic framework through a linker.

[0116] 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 on the outer surface), while the outer surface of the ceramic framework includes the inner surfaces of macropores and mesopores exposed on the outer surface. Preferably, at least the inner surface of the ceramic framework is modified with adsorption functional groups.

[0117] Methods for introducing adsorption functional groups onto the surface of a ceramic framework include: chemically immobilizing a compound with adsorption functional groups onto the surface of the ceramic framework via covalent bonds; and physically immobilizing a compound with adsorption functional groups onto the surface of the ceramic framework via physical interactions such as ionic bonds and hydrophobic interactions. Methods for chemically introducing adsorption functional groups onto the surface of a ceramic framework include reacting functional groups (e.g., hydroxyl groups) on the surface of the ceramic framework with a silane coupling agent having adsorption functional groups, thereby chemically immobilizing the silane coupling agent with adsorption functional groups onto the surface of the ceramic framework.

[0118] In one embodiment, a compound having nitrogen-containing groups is fixed to the surface of a ceramic framework, thereby modifying the surface of the ceramic framework with nitrogen-containing groups. Methods for introducing compounds having nitrogen-containing groups to the surface of a ceramic framework include: chemically fixing compounds having nitrogen-containing groups (e.g., silane coupling agents having nitrogen-containing groups) to the surface of the ceramic framework via covalent bonds; and physically fixing compounds having nitrogen-containing groups to the surface of the ceramic framework via physical interactions such as ionic bonds and hydrophobic interactions. Methods for chemically introducing compounds having nitrogen-containing groups to the surface of a ceramic framework include, for example, reacting functional groups (e.g., hydroxyl groups) on the surface of the ceramic framework with a silane coupling agent having nitrogen-containing groups to chemically fix the silane coupling agent to the surface of the ceramic framework. Compounds having nitrogen-containing groups can also be fixed to the surface of the ceramic framework using a linker. For example, after introducing a functional group that reacts with a compound having a nitrogen-containing group onto the surface of a ceramic framework, the introduced functional group can be reacted with the compound having a nitrogen-containing group to chemically fix the compound having the nitrogen-containing group onto the surface of the ceramic framework. As a method for introducing a functional group that reacts with a compound having a nitrogen-containing group onto the surface of a ceramic framework, an example is to react 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 having a nitrogen-containing group, thereby chemically fixing the silane coupling agent onto the surface of the ceramic framework. Examples of silane coupling agents having functional groups that react with compounds having nitrogen-containing groups include, for example, silane coupling agents having epoxy groups and / or halogenated alkyl groups. Examples of epoxy-containing silane coupling agents include 3-glycidoxypropyltrimethoxysilane. Examples of halogenated silane coupling agents include 3-chloropropyltrimethoxysilane.

[0119] Amine compounds can be used as compounds having a nitrogen-containing group. Preferably, the amine compound has at least one nitrogen-containing group selected from the group consisting of primary amine, secondary amine, tertiary amine, quaternary ammonium, imine, hypocyanin, and nitrogen-containing heterocyclic groups. In the amine compound, the portion other than the nitrogen-containing group can be composed of hydrogen and carbon atoms, and may also contain one or more other elements (e.g., oxygen, sulfur, halogen, silicon, etc.).

[0120] As an amine compound, at least one selected from the group consisting of monoamines, diamines, triamines, and polyamines may be used. Two or more amine compounds may also be used. The amine compound may be a silane coupling agent.

[0121] As a silane coupling agent having at least one nitrogen-containing group selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hyponitro group and nitrogen-containing heterocyclic group, examples of silane coupling agents represented by the following formulas A, B or C can be listed.

[0122] Formula A: R a -R d -Si(-R b ) n (-R c ) 3-n

[0123] Formula B: R a -R d -NH-R e -Si(-R b ) n (-R c ) 3-n

[0124] Formula C: R a -R d -NH-R e -NH-R f -Si(-R b ) n (-R c ) 3-n

[0125] In equations A, B, and C, R a Represents a primary amino group, secondary amino group, tertiary amino group, quaternary ammonium group, or a nitrogen-containing heterocyclic group, with n R groups. b Each independently represents an alkyl group, with (3-n) R groups. c Each can independently represent an alkoxy or halogen group, R d R e and R f Each can independently represent an alkylene group, an arylene group, or a combination thereof, where n represents an integer from 0 to 2.

[0126] R a Preferably, the group consisting of free primary amino groups, secondary amino groups, tertiary amino groups and nitrogen-containing heterocyclic groups is selected; more preferably, the group consisting of free primary amino groups, secondary amino groups and tertiary amino groups is selected.

[0127] As R b Alkyl groups, for example, include methyl, ethyl, propyl, butyl, etc.

[0128] As R c The alkoxy or halogen group shown can be, for example, methoxy, ethoxy, propoxy, butoxy, chloro, bromo, iodo, etc. R c Of the alkoxy groups shown, methoxy or ethoxy is preferred.c Of the halogen groups shown, chlorine groups are preferred.

[0129] As R d R e Or R f Examples of alkylene derivatives include methylene, ethylene, propylene, and butylene.

[0130] As R d R e Or R f Examples of arylene groups include phenylene, naphthylene, and biphenylene.

[0131] As R d R e Or R f The combinations of alkylene and aryl groups shown can be exemplified by groups represented by the formulas -XY-, -YX-, -XYX-, or -YXY-. In these formulas, X represents an alkylene group and Y represents an aryl group.

[0132] R d R e and R f The alkylene, arylene, or combinations thereof shown may have more than one substituent.

[0133] The monoamine preferably has a nitrogen-containing group selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypocyanin, and nitrogen-containing heterocyclic groups. 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.

[0134] The diamine preferably has two nitrogen-containing groups selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypocyanin, and nitrogen-containing heterocyclic groups. The two nitrogen-containing groups may be the same or different. Examples of diamines include silane coupling agents of Formula B, such as 3-(2-aminoethylamino)propyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride.

[0135] The triamine preferably has three nitrogen-containing groups selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium, imino, hypocyanin, and nitrogen-containing heterocyclic groups. The three nitrogen-containing groups may be the same or different. Examples of triamines include silane coupling agents of formula C, and examples of silane coupling agents of formula C include 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane.

[0136] Polyamines preferably have four or more nitrogen-containing groups selected from the group consisting of primary amine, secondary amine, tertiary amine, quaternary ammonium group, imino group, hypocyanin group, and nitrogen-containing heterocyclic group. The four or more nitrogen-containing groups may be the same or different. Examples of polyamines include polyalkylene imine, polyvinylamine, and polyallylamine.

[0137] Examples of polyalkylene imides include polymers obtained by polymerizing one or more alkylene amines using conventional methods. Polyalkylene imides can be polymers that have been 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 polybuteneimine.

[0138] 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 polyethyleneimine 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.

[0139] In one embodiment, the surface of a ceramic framework is modified with sulfonyl groups by fixing a compound having a sulfonyl group (hereinafter referred to as the "first compound") onto the surface of the ceramic framework. The above description of the method for introducing a compound having a nitrogen-containing group onto the surface of a ceramic framework also applies to the method of introducing the first compound onto the surface of a ceramic framework, unless otherwise specified. In application, "compound having a nitrogen-containing group" may be replaced with "first compound".

[0140] In one embodiment, the surface of a ceramic framework is modified with thiol groups by fixing a compound having a thiol group (hereinafter referred to as the "second compound") onto the surface of the ceramic framework. The above description of the method for introducing a compound having a nitrogen-containing group onto the surface of a ceramic framework also applies, unless specifically specified, to the method of introducing the second compound onto the surface of the ceramic framework. In application, "compound having a nitrogen-containing group" may be replaced with "second compound".

[0141] As a method for modifying the surface of a ceramic framework with sulfonation, a method can be adopted whereby a second compound is fixed to the surface of the ceramic framework, and then the thiol groups contained in the second compound are converted to sulfonation groups. The conversion from thiol groups to sulfonation groups can be carried out using conventional methods. For example, the conversion from thiol groups to sulfonation groups can be carried out by methods described later. Even if the compound initially does not contain sulfonation groups, as in the case of converting the thiol groups contained in the second compound to sulfonation groups, the case where the compound is derivatized to contain sulfonation groups after being fixed to the surface of the ceramic framework is also included in the category of "the surface of the ceramic framework is modified with sulfonation by fixing a compound containing sulfonation groups to the surface of the ceramic framework."

[0142] The portion of the first compound excluding the sulfonyl group and the portion of the second compound excluding the thiol group can be composed of hydrogen atoms and carbon atoms, respectively. They can also contain one or more other elements (e.g., oxygen atoms, nitrogen atoms, halogen atoms, silicon atoms, etc.) besides hydrogen and carbon atoms. One or more compounds can be used as the first compound and the second compound, or two or more compounds can be used. The first compound and the second compound can also be used in combination. Silane coupling agents can be used as the first compound and the second compound, respectively.

[0143] Examples of silane coupling agents containing sulfonyl groups include those represented by formula D or E.

[0144] Formula D: R g -R d -Si(-R b ) n (-R c ) 3-n

[0145] Equation E: R g -R d -Si(-O-(R h -O) m -R i ) n (-R c ) 3-n

[0146] Examples of silane coupling agents containing thiol groups include silane coupling agents represented by formulas F or G.

[0147] Formula F: R j -R d -Si(-R b ) n (-R c ) 3-n

[0148] Formula G: R j -R d -Si(-O-(R h -O) m -R i ) n (-R c ) 3-n

[0149] In formula D, R g R represents sulfonyl. b R c R d And n has the same meaning as the formulas A~C.

[0150] In formula E, R g R c R d And n has the same meaning as D in formula, R h Each independently represents an alkylene group, R i Each alkyl group is represented independently, and m represents an integer from 1 to 5, preferably an integer from 1 to 3, and more preferably an integer from 1 to 2.

[0151] In formula F, R b R c R d And n has the same meaning as D in formula, R j It represents a thiol group.

[0152] In formula G, R c R d And n has the same meaning as D in formula, R h R i And m has the same meaning as E, R j It has the same meaning as formula F.

[0153] As R h Examples of alkylene derivatives include methylene, ethylene, propylene, and butylene.

[0154] As R i Alkyl groups, for example, include methyl, ethyl, propyl, butyl, etc.

[0155] Examples of silane coupling agents represented by formula D include 3-(trimethoxysilyl)-1-propanesulfonic acid.

[0156] Examples of silane coupling agents represented by Formula E include 3-(dimethoxy(2-methoxyethoxy)silyl)-1-propanesulfonic acid.

[0157] Examples of silane coupling agents represented by formula F include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0158] Examples of silane coupling agents represented by formula G include ethoxy(3-mercaptopropyl)bis(3,6,9,12,15-pentaoxaoctadecane-1-yloxy)silane.

[0159] The amount of adsorbent functional groups contained in the first adsorbent material, based on the mass of the first adsorbent material, is preferably 0.10 mmol / g or more and 6.0 mmol / g or less, more preferably 0.10 mmol / g or more and 5.0 mmol / g or less, even more preferably 1.0 mmol / g or more and 4.0 mmol / g or less, and even more preferably 1.0 mmol / g or more and 3.0 mmol / g or less. "Amount of adsorbent functional groups" refers to the amount of that one adsorbent functional group when the first adsorbent material contains one type of adsorbent functional group, and to the total amount of the two or more adsorbent functional groups when the first adsorbent material contains two or more types of adsorbent functional groups. The amount of adsorbent functional groups can be determined using conventional methods.

[0160] When the adsorption functional group is a nitrogen-containing group, the amount of the nitrogen-containing group refers to the amount of nitrogen atoms derived from the nitrogen-containing group (i.e., the amount converted from nitrogen atoms). The amount of the nitrogen-containing group can be determined by conventional methods. For example, the amount of the nitrogen-containing group can be determined by the methods described in the examples below.

[0161] When the adsorbent functional group is sulfonyl, the amount of sulfonyl refers to the amount of sulfur atoms derived from the sulfonyl group (i.e., the amount converted from sulfur atoms). The amount of sulfonyl can be determined by conventional methods. For example, the amount of sulfonyl can be determined by the methods described in the examples described later.

[0162] When the adsorption functional group is a thiol group, the amount of thiol group refers to the amount of sulfur atoms derived from the thiol group (i.e., the amount converted from sulfur atoms). The amount of thiol group can be determined using conventional methods.

[0163] When the adsorption functional group is a phosphate group, the amount of phosphate group refers to the amount of phosphorus atoms derived from the phosphate group (i.e., the amount converted from phosphorus atoms). The amount of phosphate group can be determined using conventional methods.

[0164] When the adsorbent functional group is a phosphonic acid group, the amount of phosphonic acid group refers to the amount of phosphorus atoms derived from the phosphonic acid group (i.e., the amount converted from phosphorus atoms). The amount of phosphonic acid group can be determined using conventional methods.

[0165] When the adsorption functional group is a carboxyl group, the amount of carboxyl group refers to the amount of carbon atoms derived from the carboxyl group (i.e., the amount converted from carbon atoms). The amount of carboxyl group can be determined using conventional methods.

[0166] <Methods for converting thiol groups to sulfonyl groups>

[0167] In one embodiment, the method for converting a thiol group to a sulfonate group includes the following steps:

[0168] Step (e), modifying the surface of the porous ceramic framework with thiol groups; and

[0169] Step (f) converts the thiol group to a sulfonate group.

[0170] This method is advantageous in that it allows for easy adjustment of the amount of sulfonium groups.

[0171] Step (e) can be carried out by contacting the porous body with a reagent (hereinafter referred to as the "first reagent") used to modify the surface of the ceramic framework of the porous body with thiol groups in a first solvent.

[0172] As a first reagent, for example, a compound having a thiol group, preferably a silane coupling agent having a thiol group, or more preferably a silane coupling agent represented by formula F or G can be used.

[0173] As a primary solvent, for example, water, aqueous solutions, organic solvents and aqueous solutions, or mixtures of water can be used.

[0174] Aqueous solutions can be prepared by adding an acid to water. The acid can be selected from, for example, acetic acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc. Acetic acid is preferred. The concentration of acetic acid in the aqueous solution is, for example, 0.01% by mass or more and 5.0% by mass or less.

[0175] As organic solvents, they can be used for example, alcohol solvents such as methanol, ethanol, and propanol; ether solvents such as tetrahydrofuran and 2-methyl-tetrahydrofuran; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as methyl acetate and ethyl acetate; halogenated hydrocarbon solvents such as dichloromethane and chloroform; aromatic hydrocarbon solvents such as toluene and xylene; and aliphatic hydrocarbon solvents such as hexane and heptane.

[0176] The temperature at which the porous body contacts the first reagent in the first solvent is, for example, 60°C or higher and 100°C or lower. The contact time between the porous body and the first reagent in the first solvent is, for example, 2 hours or higher and 24 hours or lower.

[0177] After the surface of the porous ceramic framework is modified with thiol groups, the thiol-modified porous body is separated from the reaction mixture using solid-liquid separation methods such as filtration. The separated porous body is then washed with a cleaning solution such as pure water, dried, and used in step (f).

[0178] Step (f) can be carried out by contacting the thiol-modified porous body obtained in step (e) with a reagent for converting the thiol group to a sulfonate group (hereinafter referred to as the "second reagent") in a second solvent.

[0179] As a second reagent, oxidizing agents such as hydrogen peroxide, nitric acid, and m-chloroperoxybenzoic acid can be used. An aqueous solution containing an oxidizing agent can also be used as the second reagent. An aqueous solution containing an oxidizing agent can be prepared by adding the oxidizing agent to water. When using an aqueous solution containing hydrogen peroxide as the second reagent, the concentration of hydrogen peroxide in the aqueous solution is, for example, 10.0% by mass or more and 60.0% by mass or less.

[0180] Water can be used as a second solvent, for example. When hydrogen peroxide or an aqueous solution containing hydrogen peroxide is used as the second reagent, the concentration of hydrogen peroxide in the second solvent is, for example, 5.0% by mass or more and 30.0% by mass or less.

[0181] The temperature at which the thiol-modified porous body contacts the second reagent in the second solvent is, for example, 40°C or higher and 80°C or lower. The contact time between the thiol-modified porous body and the second reagent in the solvent is, for example, 0.5 hours or higher and 12 hours or lower.

[0182] After converting the thiol groups in the thiol-modified porous body to sulfonyl groups, the sulfonyl-modified porous body is separated from the reaction mixture using solid-liquid separation methods such as filtration. The separated porous body is then washed with a washing solution such as pure water and dried. This yields the sulfonyl-modified porous body.

[0183] In another embodiment, the sulfonated porous body can be manufactured by a method including a step of directly modifying the surface of the ceramic framework of the porous body with sulfonation. As such a method, for example, the method described in RSC Adv. 2017, 7, pp. 56559-56565 can be used. According to the method described in that document, by adding chlorosulfonic acid to the porous body and stirring, the surface of the ceramic framework of the porous body can be directly modified with sulfonation.

[0184] Manufacturing Methods of Adsorbent Materials

[0185] The method for manufacturing the adsorbent material of the present invention includes steps (1A) and (2A). Steps (1A) and (2A) will be described below.

[0186] <Process (1A)>

[0187] Step (1A) is a step of preparing a second adsorbent material by contacting the first adsorbent material with a liquid containing the target substance (hereinafter referred to as the "target liquid").

[0188] The treatment solution contains target substances that can be adsorbed by the adsorption functional groups of the first adsorbent material. The treatment solution may contain one target substance or two or more target substances.

[0189] Examples of liquids to be treated include wastewater discharged from factories, wastewater containing valuable metals discharged from metal refining processes, metal plating processes, etc. The liquids to be treated typically contain water. Wastewater and wastewater can be pretreated as needed before contacting the first adsorbent material.

[0190] Methods for bringing the target liquid into contact with the first adsorbent material include, for example, impregnating the target liquid with the first adsorbent material, and conveying the target liquid into a column filled with the first adsorbent material. When using the method of impregnating the target liquid with the first adsorbent material, the second adsorbent material is separated from the target liquid, for example, by solid-liquid separation such as filtration, and supplied to step (2A). When using the method of conveying the target liquid into a column filled with the first adsorbent material, the second adsorbent material can be removed from the column after the liquid delivery is completed and supplied to step (2A), or it can be supplied to step (2A) without being removed from the column after the liquid delivery is completed (i.e., in the state of a column filled with the second adsorbent material). The liquid delivery can be performed, for example, using a liquid delivery pump. The liquid delivery can be performed continuously or intermittently.

[0191] When the target liquid is brought into contact with the first adsorbent material, the target substance contained in the target liquid is adsorbed onto the first adsorbent material, resulting in a second adsorbent material. The second adsorbent material comprises the first adsorbent material and the target substance adsorbed onto the first adsorbent material. The second adsorbent material may contain one target substance or two or more target substances.

[0192] Generally, it is known that setting a higher contact treatment temperature increases adsorption efficiency. The temperature at which the target liquid comes into contact with the first adsorbent is not particularly limited; from the viewpoint of treatment cost and adsorption efficiency associated with temperature management, it can be, for example, above 25°C, above 40°C, or above 50°C. The upper limit can be, for example, below 90°C or below 70°C. These upper limits can be combined with any of the aforementioned lower limits.

[0193] In step (2A), in order to effectively remove a sufficient amount of the target substance from the second adsorbent material by contacting it with an acidic solution other than aqua regia, the second adsorbent material needs to contain a sufficient amount of the target substance. Therefore, the percentage of the amount of the target substance adsorbed in the second adsorbent material prepared in step (1A) relative to the saturated adsorption amount of the target substance in the first adsorbent material is 50% or more. This percentage is preferably 55% or more, more preferably 60% or more, even more preferably 65% ​​or more, and even more preferably 70% or more. The upper limit is 100%.

[0194] "Saturated adsorption capacity of the target substance in the first adsorbent material" refers to the amount (g) of the target substance adsorbed onto the first adsorbent material from the start of the contact treatment with the first adsorbent material until the concentration of the target substance in the treated liquid after contact with the first adsorbent material is the same as the concentration of the target substance in the treated liquid before contact with the first adsorbent material. "Amount (g) of target substance adsorbed onto the first adsorbent material" refers to the amount (g) of that single target substance when it is adsorbed onto the first adsorbent material, and to the total amount (g) of two or more target substances when they are adsorbed onto the first adsorbent material.

[0195] For example, if the target liquid is fed into a column filled with a first adsorbent to perform contact treatment between the target liquid and the first adsorbent, and the target liquid that has passed through the column is recovered into a recovery container, it is possible to determine the total amount of target substance in the target liquid recovered into the recovery container during the period from the start of liquid feeding to the end of liquid feeding, and to calculate the saturated adsorption amount of the target substance in the first adsorbent based on the following formula.

[0196] The saturated adsorption capacity of the target substance in the first adsorbent material = (the total amount of the target substance in the treatment liquid supplied to the column during the period from the start to the end of the liquid supply) - (the total amount of the target substance in the treatment liquid recovered to the recovery container during the period from the start to the end of the liquid supply)

[0197] "The amount of target substance adsorbed in the second adsorbent material prepared in step (1A)" refers to the amount (g) of target substance adsorbed into the first adsorbent material through the contact treatment in step (1A) (i.e., from the start to the end of the contact treatment). The meaning of "the amount (g) of target substance adsorbed into the first adsorbent material" is the same as described above.

[0198] For example, if the contact treatment in step (1A) is performed by conveying the target liquid to a column filled with the first adsorbent material, and the target liquid that has passed through the column is recovered to a recovery container, the total amount of the target substance recovered to the recovery container during the period from the start of liquid delivery to the end of liquid delivery can be measured, and the amount of the target substance adsorbed in the second adsorbent material can be calculated based on the following formula.

[0199] The adsorption capacity of the target substance in the second adsorbent material = (the total amount of the target substance in the treatment liquid supplied to the column during the period from the start to the end of the liquid supply) - (the total amount of the target substance in the treatment liquid recovered to the recovery container during the period from the start to the end of the liquid supply)

[0200] The amount of the target substance adsorbed on the first adsorbent material and the amount of the target substance in the treated liquid can be determined, for example, using an ICP luminescence analyzer.

[0201] <Process (2A)>

[0202] Step (2A) is a process in which the target substance is detached from the second adsorbent material by contacting it with an acidic solution other than aqua regia (sometimes referred to as "detachment treatment" in this specification), thereby obtaining the third adsorbent material. Hereinafter, the acidic solution other than aqua regia will sometimes be referred to simply as "acidic solution".

[0203] From the viewpoint of removing a sufficient amount of the target substance in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the acidic solution preferably contains at least one of the group consisting of inorganic acids and ammonium salts.

[0204] From the viewpoint of removing a sufficient amount of the target substance in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the inorganic acid preferably includes at least one selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, phosphoric acid, and boric acid, and more preferably includes at least one selected from the group consisting of hydrochloric acid and nitric acid. When the removal treatment is performed using the above-mentioned inorganic acid, it is possible to prevent the adsorption functional groups contained in the third adsorbent material from deteriorating due to the removal treatment, thereby preventing a decrease in the adsorption performance of the third adsorbent material.

[0205] From the viewpoint of removing a sufficient amount of the target substance in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the ammonium salt preferably includes at least one selected from the group consisting of ammonium chloride, ammonium sulfate, and ammonium carbonate, and more preferably includes ammonium chloride. When the removal treatment is performed using the above-mentioned ammonium salt, it is possible to prevent the adsorption functional groups contained in the third adsorbent material from deteriorating due to the removal treatment, thereby preventing a decrease in the adsorption performance of the third adsorbent material.

[0206] Examples of solvents contained in acidic solutions include water.

[0207] It should be noted that, in this specification, aqua regia refers to a mixture of concentrated hydrochloric acid and concentrated nitric acid. The volume ratio of concentrated hydrochloric acid to concentrated nitric acid in the aqua regia is, for example, 1.5 or more and 4.0 or less.

[0208] From the viewpoint of removing a sufficient amount of the target substance in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the total concentration of the inorganic acid and ammonium salt contained in the acidic solution is preferably 0.1 mol / L or more and 13 mol / L or less, more preferably 0.5 mol / L or more and 8.0 mol / L or less, and even more preferably 1.0 mol / L or more and 6.0 mol / L or less. When the total concentration is within the above range, it is possible to prevent the adsorption functional groups contained in the third adsorbent material from deteriorating due to the removal treatment, thereby preventing a decrease in the adsorption performance of the third adsorbent material. When the acidic solution contains one substance selected from the group consisting of inorganic acid and ammonium salt, the total concentration refers to the concentration of that one substance; when the acidic solution contains at least two substances selected from the group consisting of inorganic acid and ammonium salt, the total concentration refers to the total concentration of those two or more substances.

[0209] From the viewpoint of ensuring sufficient amount of the target substance is removed in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the contact treatment in step (2A) is preferably carried out at a temperature of 90°C or below, more preferably 70°C or below, and even more preferably 60°C or below. The lower limit is not particularly limited as long as it is a temperature that prevents the acidic solution from freezing. For example, the lower limit can be 1°C or above, or 20°C or above. These lower limits can be combined with any of the upper limits mentioned above.

[0210] Methods for contacting the second adsorbent material with the acidic solution include, for example, impregnating the second adsorbent material in the acidic solution or conveying the acidic solution into a column packed with the second adsorbent material. When using the method of impregnating the second adsorbent material in the acidic solution, the third adsorbent material is separated from the acidic solution and used, for example, by solid-liquid separation such as filtration. When using the method of conveying the acidic solution into a column packed with the second adsorbent material, the third adsorbent material can be used either by removing it from the column after the delivery is complete or by not removing it from the column after the delivery (i.e., by using the column packed with the third adsorbent material). At least one target substance contained in the acidic solution can be recovered using conventional methods. The recovered at least one target substance can be processed by separation, concentration, refining, etc., using conventional methods. The delivery can be performed, for example, using a delivery pump. The delivery can be continuous or intermittent.

[0211] From the viewpoint of ensuring sufficient amount of the target substance is removed in step (2A) and preventing a decrease in the adsorption performance of the adsorbent material after the removal treatment, the contact treatment in step (2A) is preferably performed using an acidic solution with a mass of 1 L / kg or more relative to the second adsorbent material. There is no particular upper limit. For example, the upper limit could be 200 L / kg or less.

[0212] When the second adsorbent material is brought into contact with an acidic solution, at least one target substance is detached from the second adsorbent material, yielding a third adsorbent material. One or more target substances can be detached from the second adsorbent material.

[0213] To prevent a decrease in the adsorption performance of the third adsorbent material, in step (2A), a sufficient amount of the target substance needs to be detached from the second adsorbent material. This is because if the target substance remains adsorbed onto the adsorbent functional groups contained in the third adsorbent material, the adsorption performance of the third adsorbent material will decrease. Therefore, the percentage of the amount of target substance detached in step (2A) relative to the amount of target substance adsorbed in the second adsorbent material prepared in step (1A) is 70% or more. This percentage is preferably 75% or more, more preferably 80% or more, and even more preferably 85% or more. The upper limit is 100%. When this percentage is within the above range, a decrease in the adsorption performance of the third adsorbent material can be prevented. Therefore, the third adsorbent material can adsorb a sufficient amount of the target substance.

[0214] The meaning of “the amount of target substance adsorbed in the second adsorbent material prepared in process (1A)” is the same as above.

[0215] "Amount of object substance removed in process (2A)" refers to the amount (g) of object substance removed from the second adsorbent material through the contact treatment in process (2A) (i.e., from the start to the end of the contact treatment). "Amount of object substance removed from the second adsorbent material (g)" refers to the amount (g) of that one object substance removed from the second adsorbent material, and refers to the total amount (g) of the two or more object substances removed from the second adsorbent material.

[0216] For example, in the case of contact treatment in step (2A) by conveying an acidic solution to a column filled with a second adsorbent material and recovering the acidic solution that has passed through the column to a recovery container, the total amount of the target substance recovered in the acidic solution to the recovery container during the period from the start of the liquid delivery to the end of the liquid delivery can be measured and used as the amount of the target substance removed in step (2A).

[0217] The amount of a substance in an acidic solution can be determined, for example, using an ICP-based luminescence analyzer.

[0218] After step (2A), the third adsorbent material can be cleaned. Cleaning can be performed using a cleaning solution such as water.

[0219] When a removal process is performed under harsh conditions (e.g., using aqua regia) with the aim of increasing the removal amount of the target substance, the adsorption performance of the adsorbent material after the removal process decreases significantly. In contrast, the method for manufacturing the adsorbent material according to the present invention enables the removal of a sufficient amount of the target substance in step (2A) without the use of aqua regia, and prevents the decrease in the adsorption performance of the third adsorbent material obtained in step (2A).

[0220] Methods for recycling target materials

[0221] The method for recycling the target substance of the present invention includes the following steps:

[0222] Step (1B) involves preparing a second adsorbent material obtained by contacting a first adsorbent material with a liquid containing the target substance; and

[0223] In step (2B), the target substance is obtained by contacting the second adsorbent material with an acidic solution other than aqua regia.

[0224] The percentage of the adsorption amount of the target substance in the second adsorbent material prepared in step (1B) relative to the saturation adsorption amount of the target substance in the first adsorbent material is 50% or more. The percentage of the detachment amount of the target substance in step (2B) relative to the adsorption amount of the target substance in the second adsorbent material prepared in step (1B) is 70% or more.

[0225] The method for recovering the target substance of the present invention can be carried out in the same manner as the method for manufacturing the adsorbent material of the present invention, except that the target substance is obtained in step (2B).

[0226] The above description of the method for manufacturing the adsorbent material of the present invention, unless otherwise specified, also applies to the method for recovering the target substance of the present invention. In application, "step (1A)" is replaced by "step (1B)" and "step (2A)" is replaced by "step (2B)".

[0227] Example

[0228] <Manufacturing Example 1>

[0229] (1) Fabrication of silica bulk

[0230] 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% (w / w) aqueous solution of acetic acid to a 150 mL reaction vessel, and stir at room temperature (25°C) 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. After heating the reaction solution in a 30°C warm bath, incubate it overnight in a 30°C incubator to prepare a polysiloxane gel.

[0231] 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 produce silica blocks. The prepared silica blocks were then pulverized and classified to obtain silica blocks with a particle size of ≥100 μm and ≤850 μm.

[0232] (2) Observation using a scanning electron microscope

[0233] The surface structure of the silica bulk obtained in (1) was observed using a scanning electron microscope (JEOL JSM-7900F), and the results confirmed that the silica bulk had a co-continuous structure.

[0234] (3) Determination of specific surface area and mode pore size of mesopores

[0235] Specific surface area and the mode pore size were determined using a specific surface area / pore distribution measuring device (BELSORP-miniX, MicrotracBEL). For silica bulk material degassed under reduced pressure at 400°C for 3 hours, nitrogen adsorption and desorption were measured at 77 K using liquid nitrogen and a multi-point method. Adsorption-desorption isotherms were derived, and the specific surface area and mode pore size were calculated based on these isotherms. The specific surface area was calculated using the BET method, and the mode pore size was calculated using the BJH method.

[0236] The BJH method is a method for analyzing the distribution of volume relative to pore diameter in pores assumed to be cylindrical, based on the Barrett-Joyner-Halenda standard model (for details, see J. Amer. Chem. Soc., 73, 373, 1951, etc.). In this invention, the analysis is performed within the range of pore diameters from 2 to 200 nm.

[0237] (4) Determination of total pore volume, mode diameter of macropores and porosity

[0238] The total pore volume, mode pore size of macropores, and porosity were determined using a mercury porosimetry instrument (AutoPore IV 9520, Micromeritics). In mercury porosimetry, pressure is applied to the pores of a silica block to allow mercury to penetrate. The pore volume and specific surface area are calculated from the pressure and the amount of mercury injected. The pore diameter is calculated from the relationship between pore volume and specific surface area when the pores are assumed to be cylindrical. In this invention, mercury porosimetry is used to analyze pores with diameters ranging from 50 nm to 500 μm. The measurements were performed under the following conditions and procedures.

[0239] (Measurement conditions)

[0240] Mercury parameters

[0241] Forward contact angle: 130.0°

[0242] Retreating contact angle: 130.0°

[0243] Surface tension: 485.0 mN / m (485.0 dynes / cm)

[0244] Mercury density: 13.5335 g / mL

[0245] Low-pressure parameters

[0246] Exhaust pressure: 50 μmHg

[0247] Exhaust time: 5.0 minutes

[0248] Mercury injection pressure: 0.0035 MPa

[0249] Balance time: 10 seconds

[0250] High pressure parameters

[0251] Balance time: 10 seconds

[0252] • Press-in volume: Adjust to 25% or more but less than 90%

[0253] • Measurement environment: 20℃

[0254] (Measurement Procedure)

[0255] (i) Weigh approximately 0.5g of sample, place it in the sample cell, and enter the weighing value.

[0256] (ii) Measure the range of 0.0048 to 0.2068 MPa in the low-pressure section.

[0257] (iii) The range of 0.2068 to 255.1060 MPa was measured in the high-pressure section.

[0258] (ii) and (iii) are performed automatically using the software attached to the device.

[0259] The results of (3) and (4) above are shown in Table 1.

[0260] [Table 1]

[0261]

[0262] (5) Fabrication of nitrogen-containing group-modified silica bulk adsorbent materials

[0263] 5.0 g of the silica bulk obtained in (1) above was added to a 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 bulk was separated from the solution by filtration, washed with 500 mL of pure water, and dried to obtain 6.44 g of nitrogen-containing group-modified silica bulk adsorbent material. 3-Aminopropyltrimethoxysilane is a silane coupling agent represented by the formula: NH2-CH2CH2CH2-Si(-OCH3)3. The nitrogen-containing group-modified silica bulk adsorbent material obtained using 3-aminopropyltrimethoxysilane contains a primary amino group (-NH2) as the nitrogen-containing group.

[0264] (6) Determination of the amount of nitrogen-containing groups

[0265] The amount of nitrogen atoms in the silica bulk adsorbent material obtained in (5) above was quantified using a LECO Nippon H836 oxygen, nitrogen, and hydrogen analyzer. The quantified amount of nitrogen atoms was taken as the amount of nitrogen-containing groups (-NH2) in the silica bulk. The amount of nitrogen-containing groups (-NH2) in the silica bulk adsorbent material was 2.8 mmol / g based on the mass of the silica bulk adsorbent material.

[0266] <Manufacturing Example 2>

[0267] (1) Fabrication of nitrogen-containing group-modified silica bulk adsorbent materials

[0268] For the silica bulk material manufactured in Manufacturing Example 1(1), 4.63 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane was used instead of 3-aminopropyltrimethoxysilane. Otherwise, surface modification was performed in the same manner as in Manufacturing Example 1(5), thereby producing a nitrogen-containing group-modified silica bulk adsorbent material. N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is a silane coupling agent represented by the formula: NH2-CH2CH2-NH-CH2CH2CH2-Si(-OCH3)3. The nitrogen-containing group-modified silica bulk adsorbent material obtained using N-(2-aminoethyl)-3-aminopropyltrimethoxysilane contains primary amino (-NH2) and imino (-NH-) groups as nitrogen-containing groups.

[0269] (2) Determination of the amount of nitrogen-containing groups

[0270] The amount of nitrogen atoms contained in the silica bulk adsorbent material obtained in (1) above was quantified using an LECO Nippon H836 oxygen, nitrogen, and hydrogen analyzer. The quantified amount of nitrogen atoms was taken as the amount of nitrogen-containing groups contained in the silica bulk. Based on the mass of the silica bulk adsorbent material, the amount of nitrogen-containing groups contained in the silica bulk adsorbent material was 2.4 mmol / g.

[0271] <Manufacturing Example 3>

[0272] (1) Fabrication of sulfonyl-modified silica bulk adsorbent material

[0273] 2.04 g of 3-mercaptopropyltrimethoxysilane, which had been stirred at room temperature for 1 hour, 35 mL of an aqueous acetic acid solution (acetic acid concentration: 0.1% by mass), and 5.0 g of the silica bulk obtained in Preparation Example 1 (1) were added to a reaction vessel. After standing at room temperature for 30 minutes, the mixture was heated at 80°C for 4 hours to prepare a thiol-modified silica bulk. The thiol-modified silica bulk was separated from the solution by filtration, washed with 500 mL of pure water, and dried to obtain 5.91 g of thiol-modified silica bulk.

[0274] 3.0 g of the obtained thiol-modified silica block, 15 mL of hydrogen peroxide (concentration: 30% by mass), and 15 mL of pure water were added to a reaction vessel and heated at 60 °C for 1 hour to convert the thiol groups to sulfonyl groups, thus preparing a sulfonyl-modified silica block. After separating the sulfonyl-modified silica block from the solution by filtration, it was washed with 500 mL of pure water and dried to obtain 3.09 g of sulfonyl-modified silica block.

[0275] (2) Determination of sulfonium content

[0276] The amount of sulfur atoms in the sulfonyl-modified silica bulk material was determined using a carbon / sulfur analysis apparatus (EMIA-Expert, manufactured by Horiba Corporation). The measured amount of sulfur atoms was taken as the amount of sulfonyl groups in the sulfonyl-modified silica bulk material. Based on the mass of the silica bulk adsorbent material, the amount of sulfonyl groups in the silica bulk adsorbent material was 1.9 mmol / g.

[0277] <Example 1>

[0278] (1) First adsorption treatment (determination of saturated adsorption capacity and fabrication of the second adsorbent material)

[0279] 0.125 g of the silica bulk adsorbent material (first adsorbent material) obtained in Manufacturing Example 2 was filled into a column (4.0 mm in diameter and 100 mm in length), and connected to a liquid delivery pump via a piping tube, thereby manufacturing... Figure 2 The flow adsorption device shown.

[0280] At room temperature (25°C), an iridium chloride solution containing 100 ppm iridium was pumped into a column at a flow rate of 0.2 mL / min using a pump. The solution that passed through the column was then recovered to a recovery container. The solution was recovered in 10 mL increments. The iridium concentration in the recovered solution reached 100 ppm after the pumping process.

[0281] The total amount of iridium in the recovered solution was determined using an ICP luminescence analyzer (SPECTROGREEN FMD46 manufactured by Hitachi High Technology Co., Ltd.). Based on the following formula, the amount of iridium adsorbed in the silica bulk adsorbent material (second adsorbent material) after the first adsorption treatment was calculated.

[0282] The amount of iridium adsorbed in the silica block adsorbent after the first adsorption treatment = (the total amount of iridium supplied to the column in the solution from the start to the end of the liquid supply) - (the total amount of iridium recovered to the recovery container in the solution from the start to the end of the liquid supply).

[0283] The amount of iridium adsorbed in the silica block adsorbent material after the first adsorption treatment is converted into the amount of iridium adsorbed per 1 kg of silica block adsorbent material (hereinafter referred to as "iridium adsorption amount").

[0284] The amount of iridium adsorbed in the silica bulk adsorbent material after the first adsorption treatment is taken as the saturated adsorption amount of iridium in the silica bulk adsorbent material.

[0285] Calculate the percentage of iridium adsorbed in the silica bulk adsorbent material after the first adsorption treatment relative to the saturated adsorption capacity of iridium in the silica bulk adsorbent material (hereinafter referred to as "iridium adsorption rate"). It should be noted that the iridium adsorption rate in the first adsorption treatment is 100%.

[0286] (2) First separation process (manufacturing of the third adsorbent material)

[0287] For the silica bulk adsorbent material (second adsorbent material) after the first adsorption treatment, the same flow adsorption device as the first adsorption treatment is used for desorption treatment.

[0288] At room temperature (25°C), 24 mL of ammonium chloride aqueous solution (ammonium chloride concentration: 5.0 mol / L) was pumped into the column at a flow rate of 0.2 mL / min using a delivery pump, and the solution that passed through the column was recovered to the recovery container.

[0289] The total amount of iridium in the recovered solution was determined using an ICP luminescence analyzer (HITACHI PS3520 UVDD) and used as the amount of iridium removed in the first removal process.

[0290] Calculate the percentage of iridium removed during the first removal treatment relative to the amount of iridium adsorbed in the silica block adsorbent material after the first adsorption treatment (hereinafter referred to as "iridium removal rate").

[0291] (3) First cleaning treatment

[0292] After the first separation process, 10 mL of pure water was pumped into the column for cleaning.

[0293] (4) Second adsorption treatment

[0294] To confirm that the adsorption capacity did not decrease after the desorption treatment, a second adsorption treatment was performed on the silica bulk adsorbent material (the third adsorbent material) after the first cleaning treatment, in the same manner as the first adsorption treatment, and the iridium adsorption amount and iridium adsorption rate in the second adsorption treatment were determined. It should be noted that when determining the iridium adsorption amount and iridium adsorption rate in the second adsorption treatment, the amount of iridium element adsorbed in the silica bulk adsorbent material after the first adsorption treatment was taken as the saturated adsorption amount of iridium element in the silica bulk adsorbent material.

[0295] (5) Second disengagement treatment

[0296] For the silica bulk adsorbent material after the second adsorption treatment, the second desorption treatment is performed in the same way as the first desorption treatment, and the iridium desorption rate in the second desorption treatment is calculated.

[0297] (6) Second cleaning treatment

[0298] After the second separation process, a second cleaning process is performed in the same manner as the first cleaning process.

[0299] (7) Third adsorption treatment

[0300] To confirm that the adsorption capacity did not decrease after the second desorption treatment, a third adsorption treatment was performed on the silica bulk adsorbent material after the second cleaning treatment, using the same method as the first adsorption treatment. The iridium adsorption amount and iridium adsorption rate in the third adsorption treatment were then determined. It should be noted that when determining the iridium adsorption amount and iridium adsorption rate in the third adsorption treatment, the iridium adsorption amount in the silica bulk adsorbent material after the first adsorption treatment was taken as the saturated adsorption amount of iridium in the silica bulk adsorbent material.

[0301] (8) Third disengagement treatment

[0302] For the silica bulk adsorbent material after the third adsorption treatment, the third desorption treatment is performed in the same way as the first desorption treatment, and the iridium desorption rate in the third desorption treatment is calculated.

[0303] (9) Third cleaning treatment

[0304] After the third detachment process, a third cleaning process is performed in the same manner as the first cleaning process.

[0305] The results are shown in Table 2. It should be noted that due to measurement errors from the device, the iridium detachment rate sometimes exceeds 100%. An iridium detachment rate exceeding 100% is denoted as "100". Similarly, in other embodiments, the detachment rate exceeding 100% is denoted as "100".

[0306] [Table 2]

[0307]

[0308] <Example 2>

[0309] Except for changing the concentration of ammonium chloride used in the desorption process to 3 mol / L, the same procedures as in Example 1 were performed. The results are shown in Table 3.

[0310] [Table 3]

[0311]

[0312] <Example 3>

[0313] Except that 12 mol / L hydrochloric acid was used instead of ammonium chloride in the desorption process, the same procedures as in Example 1 were performed. The results are shown in Table 4.

[0314] [Table 4]

[0315]

[0316] <Example 4>

[0317] The silica bulk adsorbent material used was changed to the adsorbent material prepared in Manufacturing Example 1. The solution transported in the adsorption process was changed to a palladium nitrate solution containing 100 ppm palladium. The acidic solution used in the detachment process was changed to 12 mol / L hydrochloric acid and transported at 60°C. Otherwise, the same operations as in Example 1 were performed, and the palladium adsorption amount, palladium adsorption rate, and palladium detachment rate were calculated in the same manner as in Example 1. The results are shown in Table 5. A palladium adsorption rate exceeding 100% is denoted as "100". Similarly, in other examples, cases where the adsorption rate exceeds 100% are denoted as "100". It is speculated that the reason for the adsorption rate exceeding 100% is that the saturated adsorption amount is a value lower than the theoretical maximum adsorption amount calculated from the amount of functional groups after surface modification.

[0318] [Table 5]

[0319]

[0320] <Example 5>

[0321] The acidic solution used in the desorption process was changed to 6 mol / L hydrochloric acid. Otherwise, the same procedures as in Example 4 were performed, and the palladium adsorption amount, palladium adsorption rate, and palladium desorption rate were determined in the same manner as in Example 4. The results are shown in Table 6.

[0322] [Table 6]

[0323]

[0324] <Example 6>

[0325] The acidic solution used in the desorption process was changed to 3 mol / L nitric acid. Otherwise, the same procedures as in Example 4 were performed, and the palladium adsorption amount, palladium adsorption rate, and palladium desorption rate were determined in the same manner as in Example 4. The results are shown in Table 7.

[0326] [Table 7]

[0327]

[0328] <Example 7>

[0329] The acidic solution used in the desorption process was changed to 0.5 mol / L nitric acid. Otherwise, the same procedures as in Example 4 were performed, and the palladium adsorption amount, palladium adsorption rate, and palladium desorption rate were determined in the same manner as in Example 4. The results are shown in Table 8.

[0330] [Table 8]

[0331]

[0332] <Example 8>

[0333] The temperature for the desorption process was changed to 80°C, and all other procedures were performed in the same manner as in Example 4. The palladium adsorption amount, palladium adsorption rate, and palladium desorption rate were determined in the same way as in Example 4. The results are shown in Table 9.

[0334] [Table 9]

[0335]

[0336] <Example 9>

[0337] The acidic solution used in the desorption process was changed to a 5 mol / L ammonium chloride aqueous solution, and the desorption process temperature was set to 25°C. Otherwise, the same procedures as in Example 4 were performed, and the palladium adsorption amount, palladium adsorption rate, and palladium desorption rate were determined in the same manner as in Example 4. The results are shown in Table 10.

[0338] [Table 10]

[0339]

[0340] <Example 10>

[0341] Instead of 0.125 g of the silica bulk adsorbent material (first adsorbent material) obtained in Manufacturing Example 2, 0.100 g of the silica bulk adsorbent material (first adsorbent material) obtained in Manufacturing Example 3 was filled into a column (4.0 mm in diameter and 100 mm in length). The solution transported in the adsorption process was changed to a lead nitrate solution containing 100 ppm lead, and transported at a flow rate of 0.15 mL / min at 25°C. The acidic solution used in the detachment process was changed to 1 mol / L nitric acid, and transported at a flow rate of 0.15 mL / min at 25°C. Otherwise, the same operations as in Example 1 were performed, and the lead adsorption amount, lead adsorption rate, and lead detachment rate were determined. The results are shown in Table 11. A lead adsorption rate exceeding 100% is denoted as "100". Similarly, in other examples, cases where the adsorption rate exceeds 100% are denoted as "100". It is speculated that the reason for the adsorption rate exceeding 100% is that the saturated adsorption amount is a value lower than the theoretical maximum adsorption amount calculated from the amount of functional groups after surface modification.

[0342] [Table 11]

[0343]

[0344] <Example 11>

[0345] The acidic solution used in the desorption process was changed to 6 mol / L hydrochloric acid. Otherwise, the same procedures as in Example 10 were performed, and the lead adsorption amount, lead adsorption rate, and lead desorption rate were determined in the same manner as in Example 10. The results are shown in Table 12.

[0346] [Table 12]

[0347]

[0348] <Comparative Example 1>

[0349] The acidic solution used in the detachment treatment was changed to aqua regia (the volume ratio of concentrated hydrochloric acid to concentrated nitric acid was 3). Otherwise, the same procedures as in Example 1 were performed, and the iridium adsorption amount, iridium adsorption rate, and iridium detachment rate were determined in the same manner as in Example 1. The results are shown in Table 13. It should be noted that the adsorption amount decreased significantly in the second adsorption treatment, therefore the experiment was terminated at this point.

[0350] [Table 13]

[0351]

[0352] <Comparative Example 2>

[0353] Except that an ion exchange resin (DuPont Amberlite IRA904Cl) was used instead of silica bulk adsorbent in the column, the same procedures as in Example 1 were performed, and the iridium adsorption capacity, iridium adsorption rate, and iridium detachment rate were determined in the same manner as in Example 1. The results are shown in Table 14. It should be noted that the iridium detachment rate was less than 70% in the first test, and the iridium adsorption capacity in the second test tended to decrease compared to the example; therefore, the test was terminated at this point.

[0354] [Table 14]

[0355]

[0356] Explanation of reference numerals in the attached figures

[0357] 1. Ceramic skeleton

[0358] 2···Large hole

[0359] 3··· Mesoporous

[0360] 60··· Flow Adsorption Device

[0361] 61···Column

[0362] 62···Piping pipes

[0363] 63··· Liquid delivery pump

[0364] 64···Recycling Containers

Claims

1. A method for manufacturing an adsorbent material, comprising the following steps: Step (1A): Preparing a second adsorbent material, which is obtained by contacting a first adsorbent material with a liquid containing a target substance. The first 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 the target substance selected from the group consisting of metals, metal ions, metalloids, and metalloid ions. Step (2A) involves contacting the second adsorbent material with an acidic solution other than aqua regia to detach the target substance from the second adsorbent material, thereby obtaining a third adsorbent material. The percentage of the adsorption amount of the target substance in the second adsorbent material prepared in step (1A) relative to the saturated adsorption amount of the target substance in the first adsorbent material is 50% or more. The percentage of the amount of the target substance removed in step (2A) relative to the amount of the target substance adsorbed in the second adsorbent material prepared in step (1A) is 70% or more.

2. The manufacturing method according to claim 1, wherein, The contact treatment in process (2A) is performed at a temperature below 90°C.

3. The manufacturing method according to claim 1 or 2, wherein, The acidic solution contains at least one of the following: selected from the group consisting of inorganic acids and ammonium salts.

4. The manufacturing method according to claim 1 or 2, wherein, The total concentration of inorganic acids and ammonium salts contained in the acidic solution is above 0.1 mol / L and below 13 mol / L.

5. The manufacturing method according to claim 1 or 2, wherein, The acidic solution contains at least one of the following: hydrochloric acid, nitric acid, and ammonium chloride.

6. The manufacturing method according to claim 1 or 2, wherein, The functional group comprises at least one group selected from the group consisting of primary amino, secondary amino, tertiary amino, quaternary ammonium group, imino, nitrogen-containing heterocyclic group, thiol group, sulfonyl group, phosphonic acid group and carboxyl group.

7. The manufacturing method according to claim 1 or 2, wherein, The ceramic framework comprises at least one element selected from the group consisting of silicon, aluminum, tin, cerium, titanium, and zirconium.

8. The manufacturing method according to claim 1 or 2, wherein, The target material is selected from the group consisting of transition metals containing rare earth metals, metals and metalloids of groups 13 to 16, transition metal ions containing rare earth metal ions, and metal ions and metalloids of groups 13 to 16.

9. A method for recycling a target substance, comprising the following steps: Step (1B): Preparing a second adsorbent material, obtained by contacting a first adsorbent material with a liquid containing the target substance, wherein the first adsorbent material has a co-continuous structure formed by a ceramic framework containing mesopores and macropores, and the surface of the ceramic framework is modified with functional groups capable of adsorbing the target substance selected from the group consisting of metals, metal ions, metalloids, and metalloid ions; and Step (2B) involves contacting the second adsorbent material with an acidic solution other than aqua regia to detach the target substance from the second adsorbent material, thereby obtaining the target substance. The percentage of the adsorption amount of the target substance in the second adsorbent material prepared in step (1B) relative to the saturated adsorption amount of the target substance in the first adsorbent material is 50% or more. The percentage of the amount of the target substance removed in step (2B) relative to the amount of the target substance adsorbed in the second adsorbent material prepared in step (1B) is 70% or more.

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