Metal ion chelating material, chemical sampling device including metal ion chelating material, and method of synthesizing metal ion chelating material

Abstract

A metal ion chelating material, a chemical sampling device including the metal ion chelating material, and a method of synthesizing the metal ion chelating material are provided. The metal ion chelating material comprises a first binder and a second binder, both the first binder and the second binder are used for chelating with a plurality of metal ions, the first binder is used for binding with the plurality of metal ions through non-covalent interaction, and the second binder is used for binding with the plurality of metal ions through non-covalent interaction. And the second binder is configured to chemically bind to the plurality of metal ions by metal-ligand interaction.

Description

Technical Field

[0001] The present disclosure relates to metal ion chelating materials, chemical sampling devices comprising metal ion chelating materials, and methods for synthesizing metal ion chelating materials. In particular, but not exclusively, it relates to general metal ion chelating materials for measuring and monitoring metals and cations. Background Art

[0002] Heavy metals are non-biodegradable, persistent, and may be toxic to the environment, thus causing serious environmental problems. Heavy metals tend to bioaccumulate in organisms, and the degree of accumulation depends on the total amount, concentration, and bioavailability of each metal in the environmental medium, as well as the uptake pathways, storage, metabolism, and excretion processes in the organisms. Among them, metallic radionuclides are highly toxic and have long environmental and biological half-lives, which can cause serious and long-term damage to organisms. Radionuclides in water can be concentrated and accumulated in aquatic organisms, leading to gene mutations and cancer. Radionuclides can also bioaccumulate in the food chain, resulting in higher concentrations in organisms at higher trophic levels (including humans).

[0003] Therefore, heavy metal ions and radionuclides in water may have adverse effects on the environment and aquatic organisms. It is necessary to regularly monitor the aquatic environment and protect the health of the ecosystem and the organisms therein. The bioaccumulation of heavy metals and radionuclides in aquatic organisms poses a threat to the environment and public health if the contaminated organisms are consumed. Summary of the Invention

[0004] According to a first aspect of the present disclosure, a metal ion chelating material is provided. The metal ion chelating material comprises: a first binder and a second binder, both the first binder and the second binder being used for chelating with a plurality of metal ions, wherein the first binder is used for binding to the plurality of cations through non-covalent interactions, and the second binder is used for chemically binding to the plurality of metal ions through metal-ligand coordination.

[0005] According to the first aspect, the first binder comprises a plurality of porous cavities in a porous material.

[0006] According to the first aspect, the porous material comprises a zeolite structure having the plurality of porous cavities for binding to the plurality of metal ions through non-covalent interactions.

[0007] According to the first aspect, the zeolite structure comprises porous aluminosilicate.

[0008] According to the first aspect, the second binder comprises a plurality of chelating ligands.

[0009] According to the first aspect, the zeolite structure is chemically functionalized by the plurality of chelating ligands.

[0010] According to the first aspect, the zeolite structure is functionalized by a chemical modification method, such as silanization and / or further functionalization with different chelating ligand groups.

[0011] According to the first aspect, the plurality of chelating ligands includes an imine functional group, a carboxylate functional group, an amine functional group, an iminobis(methyl acetate) functional group, an iminodiacetic acid functional group, and / or a sodium salt of iminodiacetic acid functional group.

[0012] According to the first aspect, the plurality of ions includes a plurality of cations that can be complexed into the porous cavity or coordinated with the chelating ligands.

[0013] According to the first aspect, the plurality of cations includes a plurality of cations of different metals or metal compounds, and / or radionuclides.

[0014] According to the first aspect, the plurality of cations includes UO2 2+ , Cs + and Sr 2+ and at least one of them.

[0015] According to the first aspect, the plurality of cations further includes dicationic metal ions other than UO2 2+ and Sr 2+ .

[0016] According to the first aspect, the dicationic metal ions include at least one of Hg 2+ , Cu 2+ , Ni 2+ , Pb 2+ , Zn 2+ , Co 2+ , Cd 2+ , Fe 2+ , Mn 2+ , Ba 2+ and Ca 2+ and at least one of them.

[0017] According to a second aspect of the present disclosure, a chemical sampling device is provided. The chemical sampling device includes: a closed cavity and a metal ion chelating material according to the first aspect contained in the closed cavity.

[0018] According to the second aspect, the chemical sampling device is used to capture the plurality of metal ions in a sampling environment.

[0019] According to the second aspect, the sampling environment includes a marine environment or a freshwater environment.

[0020] According to a third aspect of the present disclosure, a method for synthesizing a metal ion chelating material is provided. The method includes: silanizing and / or further functionalizing a zeolite structure with a plurality of chelating ligands, wherein the zeolite structure is operably used as a first binder for binding to a plurality of metal ions through non-covalent interactions, and the plurality of chelating ligands are operably used as a second binder for chemically binding to the plurality of metal ions through metal-ligand coordination.

[0021] According to the third aspect, the metal ion chelating material is prepared by the following steps: stirring a first suspension containing ethanol-water (EtOH-H2O), 3-aminopropyltrimethyoxysilane, and a predetermined amount of zeolite; collecting a first precipitate in the stirred first suspension by suction filtration; and thermally curing the first precipitate to obtain a metal ion chelating material including a first modified zeolite, the first modified zeolite including a zeolite structure silanized through an amine functional group.

[0022] According to the third aspect, the metal ion chelating material is prepared by the following steps: dropping methacrylate into a methanol (MeOH) solution containing the first modified zeolite to obtain a second suspension; collecting a second precipitate in the heated and stirred second suspension by suction filtration; and drying the second precipitate to obtain a metal ion chelating material including a second modified zeolite structure, the second modified zeolite structure including a zeolite structure silanized through an amine functional group and / or an iminodiacetic acid methyl ester functional group.

[0023] According to the third aspect, the metal ion chelating material is prepared by the following steps: heating and stirring a third suspension containing the second modified zeolite in formic acid; collecting a third precipitate from the third suspension by suction filtration; and drying the third precipitate to obtain a metal ion chelating material including a third modified zeolite structure, the third modified zeolite structure including a zeolite structure silanized through an amine functional group, an iminodiacetic acid methyl ester functional group, and / or an iminodiacetic acid functional group.

[0024] According to the third aspect, the metal ion chelating material is prepared by the following steps: stirring a fourth suspension containing the third modified zeolite in an aqueous sodium carbonate solution; collecting a fourth precipitate from the fourth suspension by suction filtration; and drying the fourth precipitate to obtain a metal ion chelating material including a fourth modified zeolite structure, the fourth modified zeolite structure including a zeolite structure silanized through an amine functional group, an iminodiacetic acid methyl ester functional group, an iminodiacetic acid functional group, and / or an iminodiacetic acid sodium salt functional group. Description of the Drawings

[0025] Embodiments of the present disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0026] Figure 1 Schematic diagram for preparing a functionalized porous silicoaluminate material / zeolite as a general cation chelating material according to an embodiment of the present disclosure.

[0027] Figure 2A Schematic diagram of the silanization process of a zeolite with amine functional groups.

[0028] Figure 2B Schematic diagram of the functionalization process of a silanized zeolite with iminodiacetic acid methyl ester functional groups.

[0029] Figure 2C Schematic diagram of the functionalization process of a silanized zeolite with iminodiacetic acid functional groups.

[0030] Figure 2D Schematic diagram of the functionalization process of a silanized zeolite with sodium iminodiacetate functional groups.

[0031] Figure 3 Schematic diagram of the IR spectra of unmodified and iminoacetate-functionalized zeolites in the region of 1150 to 2100 cm -1 of.

[0032] Figure 4 Shows an exemplary chemical sampling device or artificial mussel according to an embodiment of the present disclosure.

[0033] Figure 5 Schematic diagram of the absorption capacity of different metal chelating materials for Cs + 、UO2 2+ and Sr 2+ ions on the 1st day, 2nd day and 5th day.

[0034] Figure 6 Schematic diagram of the absorption capacity of Chelex-100 and functionalized zeolite 4 for various bicationic metal ions. DETAILED DESCRIPTION

[0035] The inventors have designed metal ion chelating materials, such as Chelex-100, which can be used to monitor metals and cations in the aquatic environment. For example, artificial mussels can be equipped with Chelex-100 or other metal ion chelating materials to bind or capture the ions of different metals present in the sampling environment, and the captured ions can be further extracted for subsequent analysis.

[0036] However, some metal ion chelating materials may have limitations in effectively capturing or binding to a wide variety of cations. Notably, radioactive cesium ions, which are common among the radionuclides produced in nuclear fission in uranium-based nuclear power plants, cannot be effectively chelated or captured by Chelex-100.

[0037] Although some porous materials may be able to capture cesium ions, these materials may have limited ability to capture a wide range of metal ions and may thus be unsuitable for environmental monitoring applications. The inventors have devised that, in order to effectively monitor the entire spectrum of cations / metal ions of interest, multiple types of artificial mussels using different metal ion chelating materials must be utilized.

[0038] In addition, for different types of artificial mussels, multiple extraction processes and separate quantitative analysis of metal ions may be required in order to perform quantitative analysis of different metal ions. This will inevitably reduce the efficiency of monitoring metal ions and result in a significant increase in monitoring costs.

[0039] In order to capture a wider range of metal ions and thereby enhance the corresponding artificial mussels as more effective metal ion samplers, covering all metal ions and radionuclide species of interest, preferably, new materials based on functionalized metal ion chelating ligand groups of porous materials can be used.

[0040] Reference Figure 1 , an embodiment of a metal ion chelating material 100 is shown. The metal ion chelating material 100 includes a first binder 102 and a second binder 104. Both the first binder 102 and the second binder 104 are used for chelating with multiple cations. The first binder 102 is used for binding to multiple metal ions through non-covalent interactions. The second binder 104 is used for chemically binding to multiple metal ions through metal-ligand coordination.

[0041] In the present disclosure, cations may include ions of metals or metal compounds, particularly ions of heavy metals or transition metals or their compounds, or ions of non-metals such as NH4 + . In addition, the term "metal" can be interpreted as "metal ions" as commonly understood by those skilled in the art (such as chemists, environmental scientists or engineers).

[0042] In the present embodiment, the first binder 102 includes porous aluminosilicate having a zeolite structure. Zeolite is a crystalline aluminosilicate having a porous material and a large surface area, and thus has multiple porous cavities, which are used for binding to multiple metal ions through non-covalent interactions and can be used to capture metal ions from an aqueous solution, such as radioactive cesium ions.

[0043] Preferably, the zeolite structure contains donor atoms, such as N-donor and / or O-donor moieties, which can bind cations, such as cesium ions, through non-covalent interactions.

[0044] During operation, cations or metal ions such as cesium ions can bind within the pores of the zeolite. The selectivity of the zeolite for metal ions such as cesium ions stems from the size of the cesium ions, which may be similar to the size of the pores in the zeolite structure. Thus, by selecting a suitable type of zeolite, selective binding / capture of a specific cation of interest can be achieved. Advantageously, using zeolite to remove cesium ions from an aqueous solution is an effective method capable of removing the radioactive isotope Cs-137 of cesium present at low concentrations in seawater or other samples.

[0045] Alternatively, multiple metal ions include multiple radionuclides and their cations, such as but not limited to uranium-238, thorium-232, potassium-40, and radium-226, where their ions are monocations. Additionally, other types of porous silicate / silica materials can also be used, provided that the porous material can be chemically modified as further described below.

[0046] Preferably, the metal ion chelating material further comprises a second binder 104, which is used to bind or capture other metal ions, such as but not limited to UO 2+ 、Sr 2+ 、Hg 2+ 、Cu 2+ 、Ni 2+ 、Pb 2+ 、Zn 2+ 、Co 2+ 、Cd 2+ 、Fe 2+ 、Mn 2+ 、Ba 2+ and Ca 2+ . These are examples of divalent cation metal ions or heavy metal cations, which can be chemically captured by the metal ion chelating material, preferably by special functional groups functionalized on the metal ion chelating material.

[0047] For example, the zeolite structure is chemically functionalized with multiple chelating ligands. Thus, the modified zeolite structure has chelating ligands that function as a second binder to chemically chelate or bind specific types of metal ions, such as heavy metals, which are typically multivalent transition metals and are generally toxic to aquatic organisms. Preferably, the chelating ligand can contain an iminodiacetate moiety, which can act as a chelating group in binding multivalent metal ions.

[0048] Reference Figure 1, the zeolite structure can be modified or chemically functionalized by suitable chemical modification methods (such as silanization) in order to "anchor" the desired functional groups to the surface of the zeolite structure. Optionally, the silicated zeolite structure can be further chemically modified by subsequent partial functionalization with different chelating ligands in order to anchor different functional groups for chelating the desired cations.

[0049] In this example, a silane containing a chemical functional group is used to perform a silanization reaction with a porous material, and in combination with a subsequent chemical functionalization process, a metal ion chelating material is prepared / manufactured. Advantageously, since both the chelating functional groups (ligands) and the porous cavities are capable of binding to different types of cations, compared with materials having only porous cavities or chelating ligands in other example materials, the cation chelating material having porous cavities and chelating ligands can bind to a wider range of metal ions.

[0050] Preferably, the plurality of chelating ligands or the second binder 104 includes at least one of an amine functional group, a carboxylate group, an imine group, an iminobis(methyl acetate) functional group, an iminodiacetic acid functional group, and / or a sodium salt functional group of iminodiacetic acid. The selectivity of the modified zeolite structure depends on the choice of functional groups anchored to the zeolite structure and / or the zeolite type.

[0051] According to the inventors' design, a similar design strategy can be applied to other porous materials and chelating functional groups. In addition, in addition to silanization and subsequent functionalization, other chemical modification reactions of the material can be applied to provide other metal ion / cation chelating materials with similar designs.

[0052] Also refer to Figure 2A , the zeolite 202 can be silanized by an amine functional group 204: by stirring a suspension containing ethanol-water (EtOH-H2O), 3-aminopropyltrimethyoxysilane, and a predetermined amount of zeolite; collecting the precipitate in the stirred suspension by suction filtration; and thermally curing the precipitate to obtain a metal ion chelating material including a first modified zeolite 200A, the first modified zeolite comprising a zeolite structure 202 silanized by an amine functional group 204.

[0053] In an exemplary embodiment, a specific type of zeolite (11.9 g, 73.3 mmol) was added to a solution of 50 mL EtOH-H2O (4:1, v / v) and 3-aminopropyltrimethoxysilane (APTMS, 6.4 ml, 35.7 mmol) to obtain a suspension. After stirring at room temperature for 3 hours, the brown precipitate could be collected by suction filtration. After washing with EtOH (20 mL × 3) and subsequently incubating at 110 °C to thermally cure the silanized material, the cured solid could be washed with EtOH (20 mL × 3) and dried at 70 °C for 15 hours. Silanized zeolite 1 (i.e., the first modified zeolite) could be obtained as a brown powder (yield: 10.5 g). IR (KBr disk, cm -1 ): 3281br, 1644, 1483 (N-H bending), 1483, 1423, 1197, 1108, 1057, 990.

[0054] Alternatively or additionally, the zeolite can be silanized with iminodiacetic acid methyl ester functional groups, iminodiacetic acid functional groups, and / or sodium iminodiacetate functional groups. For example, referring to Figure 2B , silanized zeolite 202 or modified zeolite can be functionalized with iminodiacetic acid methyl ester functional group 206: Methyl acrylate (MA) was added dropwise to a MeOH solution containing (modified) zeolite to obtain a suspension; after heating and stirring, the precipitate was collected from the suspension by suction filtration; and the precipitate was dried to obtain a metal ion chelating material 200B, which includes a silanized zeolite structure 202 further having an iminodiacetic acid methyl ester functional group 206.

[0055] For example, at 0 °C, methyl acrylate (24.0 mL, 264 mmol) could be added dropwise to a solution of the first modified zeolite (10 g) in MeOH (40 mL). The resulting mixture could be warmed to 80 °C and stirred at this temperature for 24 hours. After cooling to room temperature, the light brown precipitate could be collected by suction filtration and washed with EtOH (20 mL × 3). After drying at 70 °C for 15 hours, the second modified zeolite (i.e., zeolite 2) in the form of a light brown powder could be obtained (yield: 11.7 g). IR (KBr disk, cm -1 ): 3296br, 1738 (C=O stretching), 1642, 1585, 1469, 1417, 1317 (C-O stretching), 1192, 1103, 1050, 989, 880, 797, 747, 699, 674. In this example, the second modified zeolite structure 200B contains a silanized zeolite structure 202 having an amine functional group 204 and further functionalized with an iminodiacetic acid methyl ester functional group 206.

[0056] Alternatively, if the unmodified zeolite is modified by these silylation and functionalization methods, different modified zeolites can be obtained, among which only the iminodiacetic acid methyl ester functional group is used for functionalization.

[0057] Reference Figure 2C , zeolite 202 or the modified zeolite can be functionalized by the iminodiacetic acid functional group 208: heating and stirring a suspension containing the zeolite or the modified zeolite in formic acid; collecting the precipitate from the suspension by suction filtration; and drying the precipitate to obtain a metal ion chelating material 200C containing a zeolite structure 202 further functionalized by the iminodiacetic acid functional group 208.

[0058] A suspension of zeolite 2 (10 g) in formic acid (60 mL) can be heated to 80 °C and stirred for 12 hours. The resulting mixture can be cooled to room temperature. The resulting brown precipitate can be collected by suction filtration and then washed with deionized water (20 mL × 5) and EtOH (20 mL × 3). After drying at 70 °C, zeolite 3 (i.e., the third modified zeolite) in the form of a brown powder can be obtained (yield: 8.64 g). IR (KBr disk, cm -1 ): 3406br, 1725 (C=O stretching), 1708, 1632, 1587, 1534, 1511, 1473, 1447 (C-H bending), 1412 (O-H bending), 1380 (C-H bending), 1357, 1313 (C-O stretching), 1160, 1053, 965, 882, 797. In this example, the third modified zeolite structure 200C contains a silylated zeolite structure 202 having an amine functional group 204 and / or an iminodiacetic acid methyl ester functional group 206 and is further functionalized by the iminodiacetic acid functional group 208.

[0059] Alternatively, if the unmodified zeolite is modified by these silylation and functionalization methods, different modified zeolites can be obtained, among which only the iminodiacetic acid functional group is used for functionalization.

[0060] Reference Figure 2D , zeolite 202 or the modified zeolite can be functionalized by the sodium iminodiacetate functional group 210: stirring a suspension containing the zeolite or the modified zeolite in an aqueous sodium carbonate solution; collecting the precipitate from the suspension by suction filtration; and drying the precipitate to obtain a metal ion chelating material 200D including a silylated zeolite structure 202 having the sodium iminodiacetate functional group 210.

[0061] For example, a suspension of zeolite 3 (5 g) in an aqueous solution of 2 M sodium carbonate (100 mL) can be vigorously stirred at room temperature for 24 hours. The brown precipitate can be collected by suction filtration. After drying at 70 °C for 15 hours, zeolite 4 or the fourth zeolite structure (2.29 g) in the form of a light brown powder can be obtained. IR (KBr disk, cm -1 -1): 3383br, 1703 (C=O stretch), 1667, 1642, 1544, 1498, 1465 (C-H bend), 1406 (C-H bend), 1343 (C-O stretch), 1199, 1037, 960, 784, 665. In this example, the fourth modified zeolite structure 200D contains a silylated zeolite structure 202 having an amine functional group 204 and / or an iminobis(acetic acid methyl ester) functional group 206 and / or an iminobis(acetic acid) functional group 208, and is further functionalized by an iminobis(acetic acid) sodium salt functional group 210.

[0062] Alternatively, if the unmodified zeolite is modified by these silylation and functionalization methods, different modified zeolites can be obtained, in which only the iminobis(acetic acid) sodium salt functional group is used for functionalization.

[0063] Those skilled in the art should understand that the combination of the modification of the zeolite structure or material with N-donors and / or O-donors such as amine functional groups, imine groups, carboxylic acid ester groups, iminobis(acetic acid methyl ester) functional groups, iminobis(acetic acid) functional groups, and iminobis(acetic acid) sodium salt functional groups can be selectively selected by modifying the zeolite structure with two or more of these modification methods, depending on the desired range of metal ions for which the chelating material is designed to act. For example, the zeolite structure 202 functionalized by an iminobis(acetic acid methyl ester) functional group 206 and / or an iminobis(acetic acid) functional group 208 can be obtained by modifying the zeolite structure 202 according to Figure 2B and 2C the methods shown. In addition, process parameters such as stirring, heating / drying / curing temperature, and reaction duration can be varied according to different process settings and / or desired material compositions during manufacturing.

[0064] Refer to Figure 3 , which shows the IR spectra of the unmodified and iminoacetate-functionalized zeolites (zeolite 4 as described above) in the 1150 to 2100 cm -1 -1 region, where the dotted line represents the signal of the zeolite. For clarity, the stretching and bending modes of the iminobis(acetic acid) functional group of the iminobis(acetic acid)-functionalized zeolite are shown as ν and δ, respectively, in the labeled IR peaks.

[0065] Refer to Figure 4, showing an embodiment of a chemical sampling device 400. The chemical sampling device 400 includes an enclosed cavity 402 and a metal ion chelating material 404 contained within the enclosed cavity 402. In this embodiment, the chemical sampling device 400 includes a protective cap 406 that encloses a tube 408 which houses two layers (e.g., 1 cm thick) of polyacrylamide gel 410 that sandwich the enclosed cavity 402 containing a certain amount of metal ion chelating material 404. The tube 408 can have a diameter of 25 mm and a length of 60 mm. The protective cap 406 is provided with an opening 412 that allows for fluid communication of the metal ion chelating material 404 to contact seawater or fresh water surrounding the device 400, such that the chemical sampling device can capture various metal ions in a sampling environment, similar to an "artificial mussel" operating in a marine environment or other sampling environment. For example, the chemical sampling device 400 can be used to monitor 238 U, 88 Sr, and 133 Cs.

[0066] The inventors designed that mussels have a remarkable ability to accumulate radionuclides and metals from water and planktonic food, and thus can be used to monitor radionuclides and metals in the aquatic environment. However, both the uptake and retention of radionuclides and metals by mussels can be affected by major physical factors (e.g., salinity, temperature, food availability) and biological factors (e.g., seasonal growth and reproductive conditions) in the environment. For example, it was found that there was no seasonal variation in the concentration of radionuclides in seawater along the Portuguese Atlantic coast. However, significant seasonal variations in 210 Po and 210 Pb in mussels were evident during the same period, which can be attributed to changes in body weight and the concentration of lipophilic compounds in mussels. These confounding factors can make it very difficult (if not impossible) to compare the levels of radionuclides and metals in mussels over time under different hydrographic conditions. More importantly, the distribution range of mussel species in the natural environment is limited, which generally cannot be compared over a large area.

[0067] In contrast, passive samplers "artificial mussels" (AMs) can be used as rapid and cost-effective chemical sampling devices for monitoring radionuclides and metals in the environment. Advantageously, "artificial mussels" can provide a time-integrated estimate of metal concentrations in marine and freshwater environments. In addition, AMs can provide reliable time-integrated estimates of various metals over large biogeographical regions with very different hydrographic conditions, thus overcoming the long-term problems of monitoring metals in water, sediment, and biological monitors. In addition, AMs can also absorb U and other metal substances from water, although U was not detected in natural mussels deployed at the same location.

[0068] The inventors also envision that, in order to monitor radionuclides in the aquatic environment, it is crucial for AMs to meet the following three criteria: (a) be able to concentrate radionuclides at environmentally relevant concentrations from the environment; (b) the accumulation, uptake, and release of radionuclides be directly related to the concentration of radionuclides in water; and (c) the uptake and release of any single radionuclide not be significantly affected by the presence of other radionuclides in the environment.

[0069] Chemical analysis of metals and radionuclides concentrated from the sampling environment by AM can be carried out as follows. In one exemplary operation, the metal ion chelating material of each individual AM can be emptied into a sintered glass filter and eluted after rinsing three times with 12.5 mL of 6M HNO3 (analytical grade). Then, the seawater sample and the eluate solution can be supplemented with deionized double-distilled water to a known volume, and using an Optima 8000 ICP-OES and a NexION 2000 ICP-MS (plasma flow: 15 L / min; auxiliary flow: 0.3 L / min; spray flow: 0.8 L / min; RF power: 1300 W, pump speed: 1.0 mL / min), after calibration with a standard solution (1000 mg / mL, 2% HNO3), the metal concentration captured in the eluate solution is determined, such as 238 U, 88 Sr, and 133 Cs. In this detection setup, 88 Sr, 133 Cs, and 238 U can have a detection limit of 0.1 μg / g. The accuracy of the analysis can then be evaluated by measuring replicate samples and determined by a standard calibration curve with 1, 10, 25, 50, 100, 500, and 1000 μg / L.

[0070] Binding studies of metal ions (Cs + , Sr 2+ and UO2 2+ ) associated with radioactive isotope problems were carried out by immersing 100 mg each of metal ion chelating materials (including the commercially available metal chelating material Chelex-100, the porous material zeolite before chemical modification, and the novel iminodiacetic acid-functionalized zeolite 4 described above, i.e., the fourth modified zeolite) into an aqueous solution containing cesium (Cs + , 1.5 ppb, Cs2CO3), uranium (UO2 2+ , 15 ppb, UO2(OAc)2), and strontium (Sr 2+ , 50 ppm, SrCl2) in 25 mL of deionized water. The metal ion concentrations in the solution were determined by ICP-MS on day 0, day 1, day 2, and day 5.

[0071] To evaluate the binding affinity of iminoacetate-functionalized zeolite 4 compared to Chelex-100, the study evaluated the capture efficiency for a series of metal ions, including Hg 2+ , Cu 2+ , Ni 2+ , Pb 2+ , Zn 2+ , Co 2+ , Cd 2+ , Fe 2+ , Mn 2+ , Ba 2+ and Ca 2+ ions. This was achieved by quantifying the decrease in the concentration of these metal ions from day 0 to day 5 after immersing the material into a solution of each metal ion, thus providing a comparative analysis of the metal chelating ability of 4 and Chelex-100.

[0072] Reference Figure 5 , for UO2 2+ , Cs + and Sr 2+ ions, Chelex-100 showed a high binding affinity for UO 2+ and Sr 2+ ions, but a poor affinity for Cs + ions. This is consistent with the poor metal binding affinity of Chelex-100 for monocationic metal ions. Zeolite showed a high binding affinity for Cs + and Sr 2+ ions, but a poor binding affinity for UO2 2+ ions. The poor binding affinity of zeolite for UO2 2+ can be attributed to the mismatch between the ion size and the zeolite pores.

[0073] In contrast, for iminoacetate-functionalized zeolite 4, it showed a high binding affinity for Cs + , UO2 2+ and Sr 2+ ions. This is due to the synergistic effect of the binding interactions of the pores and the iminoacetate moieties covalently linked to the porous material. As a result, iminoacetate-functionalized zeolite 4 can bind monocationic metal ions and ions whose size does not fit well into the pores of the porous material.

[0074] Reference Figure 6, for other dicationic metal ions, compared with Chelex-100, iminodiacetate-functionalized zeolite 4 also binds those ions (reported to bind to Chelex-100). These results confirm that porous materials functionalized with iminodiacetic acid functional moieties can capture a significantly more diverse range of metal ions and cations.

[0075] Furthermore, different types of porous materials and metal ion-binding functional groups can be used to modulate further variations in binding ability and capacity. Advantageously, artificial mussels equipped with a general metal ion chelating material (i.e., a porous material functionalized with a metal ion-binding moiety) can be used as effective tools for monitoring a broad spectrum of radionuclide ions and heavy metal ions.

[0076] These embodiments may be advantageous because monitoring pollution in the aquatic environment, e.g., by using chemical sampling devices and metal ion chelating materials according to the above embodiments, can help identify pollution sources and the extent of pollution, which can aid in formulating effective mitigation strategies. Additionally, direct monitoring of pollution sources, e.g., radioactive pollutant discharges from nuclear power plants into water, may be useful to assess the impact on the aquatic environment and / or aquatic organisms.

[0077] Furthermore, monitoring heavy metal ions and / or radionuclide ions can also provide support for environmental science and contribute to the development of key scientific understandings of the aquatic environment and the impact of human activities on it.

[0078] Those skilled in the art will understand that various changes and / or modifications can be made to the present disclosure as shown in the specific embodiments without departing from the spirit or scope of the present disclosure as broadly described. Accordingly, this embodiment is to be considered in all respects illustrative and not restrictive.

[0079] Unless otherwise indicated, any reference to prior art contained herein should not be construed as an admission that such information is common general knowledge.

Claims

1. A metal ion chelating material, characterized in that, Comprising: A first binder and a second binder, both the first binder and the second binder being used for chelating with a plurality of metal ions, wherein the first binder is used for binding to a plurality of cations through non-covalent interactions, and the second binder is used for chemically binding to the plurality of metal ions through metal-ligand coordination.

2. The metal ion chelating material according to claim 1, characterized in that, Wherein, The first binder comprises a plurality of porous cavities in a porous material.

3. The metal ion chelating material according to claim 2, wherein Wherein, The porous material comprises a zeolite structure having the plurality of porous cavities for binding to the plurality of metal ions through non-covalent interactions.

4. The metal ion chelating material according to claim 3, characterized in that, Wherein, The zeolite structure comprises porous aluminosilicate.

5. The metal ion chelating material according to claim 4, characterized in that, Wherein, The second binder comprises a plurality of chelating ligands.

6. The metal ion chelating material according to claim 5, characterized in that, Wherein, The zeolite structure is chemically functionalized by the plurality of chelating ligands.

7. The metal ion chelating material according to claim 6, characterized in that, Wherein, The zeolite structure is functionalized by a chemical modification method.

8. The metal ion chelating material according to claim 6, characterized in that, Wherein, The plurality of chelating ligands include imine functional groups, carboxylate functional groups, amine functional groups, iminobis(methyl acetate) functional groups, iminodiacetic acid functional groups, and / or sodium iminodiacetate functional groups.

9. The metal ion chelating material according to claim 1, wherein Wherein, The plurality of metal ions include a plurality of cations of different metals or metal compounds, and / or radionuclides.

10. The metal ion chelating material according to claim 9, wherein Wherein, The plurality of metal ions includes UO2 2+ , Cs + and Sr 2+ and at least one of them.

11. The metal ion chelating material according to claim 10, characterized in that, Wherein, The plurality of metal ions further includes divalent cation metal ions other than UO2 2+ and Sr 2+ 。 12. The metal ion chelating material according to claim 11, wherein Wherein, The double cation metal ions include Hg 2+ , Cu 2+ , Ni 2+ , Pb 2+ , Zn 2+ , Co 2+ , Cd 2+ , Fe 2+ , Mn 2+ , Ba 2+ and Ca 2+ and at least one of them.

13. A chemical sampling device, characterized in that, Comprising: A closed cavity and the metal ion chelating material according to claim 1 contained in the closed cavity.

14. The chemical sampling device according to claim 13, characterized in that, Wherein, The chemical sampling device is used for capturing the plurality of metal ions in a sampling environment.

15. The chemical sampling device according to claim 14, wherein, Wherein, The sampling environment includes a marine environment or a fresh water environment.

16. A method for synthesizing a metal ion chelating material, characterized in that, Wherein, comprising: silanizing and / or further functionalizing a zeolite structure with a plurality of chelating ligands, wherein the zeolite structure is operably used as a first binder for binding to a plurality of metal ions through non-covalent interactions, and the plurality of chelating ligands are operably used as a second binder for chemically binding to the plurality of metal ions through metal-ligand coordination.

17. The method according to claim 16, wherein Wherein, The metal ion chelating material is prepared by the following steps: Stirring a first suspension containing ethanol-water (EtOH-H2O), 3-aminopropyltrimethyoxysilane, and a predetermined amount of zeolite; Collecting a first precipitate in the stirred first suspension by suction filtration; And Thermally curing the first precipitate to obtain a metal ion chelating material comprising a first modified zeolite, the first modified zeolite comprising a zeolite structure silanized through amine functional groups.

18. The method according to claim 17, wherein Wherein, The metal ion chelating material is prepared by the following steps: Dropping methacrylate into a methanol (MeOH) solution containing the first modified zeolite to obtain a second suspension; Collecting a second precipitate in the heated and stirred second suspension by suction filtration; Drying the second precipitate to obtain a metal ion chelating material comprising a second modified zeolite structure, the second modified zeolite structure comprising a zeolite structure silanized through amine functional groups and / or iminobis(methyl acetate) functional groups.

19. The method according to claim 18, characterized in that, Wherein, The metal ion chelating material is prepared by the following steps: Heating and stirring a third suspension containing the second modified zeolite in formic acid; Collect a third precipitate from the third suspension by suction filtration; and dry the third precipitate to obtain a metal ion chelating material comprising a third modified zeolite structure, the third modified zeolite structure comprising a zeolite structure silylated by an amine functional group, an iminodiacetic acid methyl ester functional group, and / or an iminodiacetic acid functional group.

20. The method according to claim 19, wherein Wherein, the metal ion chelating material is prepared by the following steps: Stir a fourth suspension containing the third modified zeolite in an aqueous sodium carbonate solution; Collect a fourth precipitate from the fourth suspension by suction filtration; and dry the fourth precipitate to obtain a metal ion chelating material comprising a fourth modified zeolite structure, the fourth modified zeolite structure comprising a zeolite structure silylated by an amine functional group, an iminodiacetic acid methyl ester functional group, an iminodiacetic acid functional group, and / or an iminodiacetic acid sodium salt functional group.

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