Imprinted mesoporous material for adsorption of rare earth ions and preparation method thereof

Abstract

The application provides an imprinted mesoporous material for adsorbing rare earth ions and a preparation method thereof. The method comprises the following steps: (1) subjecting pretreated biomass waste to hydrolysis treatment to obtain chiral nanocrystals; (2) reacting a solution containing the chiral nanocrystals in step (1), a silane coupling agent modified by a functional monomer, a silicon source and an imprinted ion source to obtain a precursor material; and then subjecting the precursor material to evaporation drying and double-template removal treatment in sequence to obtain the ion imprinted mesoporous material. The efficient independent ion imprinted mesoporous film prepared by the application meets the use requirements of high adsorption capacity and high selectivity, realizes effective utilization of biomass waste resources, and is beneficial to recycling of low-concentration rare earth ions in mineral waste residue tail liquid.

Description

Technical Field

[0001] This invention belongs to the field of adsorbent materials technology, specifically relating to an imprinted mesoporous material for rare earth ion adsorption and its preparation method. Background Technology

[0002] Rare earth ions, including lanthanides and seventeen other subgroup ions such as scandium and yttrium, are considered a crucial strategic resource for developing fields such as wind turbines, electric vehicle engines, medical diagnostics, and oil refining due to their unique optical, electrical, and magnetic properties. However, there are some problems with the utilization and recycling of rare earth ions. For example, the existing ammonium bicarbonate precipitation conversion process cannot effectively recover low-concentration rare earth ions from in-situ leaching solutions, resulting in serious rare earth loss and water pollution.

[0003] Currently, reported methods for recovering metal ions from wastewater with low concentrations of metal ions mainly include chemical precipitation, extraction, ion exchange, membrane separation, and adsorption. Among these, adsorption is considered the most feasible method for recovering and separating low-concentration metal ions due to its advantages such as good separation effect, simple operation, no need for external auxiliary conditions, low energy consumption, and the ability to selectively adsorb, separate, and enrich low-concentration metal ions in wastewater by selecting different adsorbents. In recent years, researchers have mostly used adsorbents containing natural minerals, oxides, nanocomposite materials, or microorganisms to adsorb metal ions.

[0004] Although the aforementioned rare earth ion adsorbents have made some progress in improving maximum adsorption capacity and desorption rate, they still suffer from low adsorption capacity and poor selectivity in treating low-concentration rare earth wastewater. To address these issues, researchers typically employ physical or chemical methods. Physical methods specifically utilize mesoporous materials with highly ordered pore structures and high specific surface areas, which can effectively enhance adsorption capacity. Most publicly available mesoporous materials are synthesized using template methods, with soft template methods being the most studied. Soft template methods often use surfactants, but this is not environmentally friendly. Hard template methods are less studied. According to existing literature, environmentally friendly cellulose nanocrystals can be used as hard templates to prepare mesoporous materials, but the control of the pore structure of mesoporous membranes and the achievement of high adsorption capacity and high selectivity have not yet been realized.

[0005] Therefore, there is an urgent need to develop an adsorbent material with high adsorption capacity and high selectivity to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an imprinted mesoporous material for rare earth ion adsorption and its preparation method. This invention utilizes the chiral phase array structure of biomass nanocrystals as a hard template and rare earth ions as imprinting site templates to prepare highly efficient freestanding ion-imprinted mesoporous films (IMMs). While meeting the requirements for high adsorption capacity and high selectivity, this invention achieves effective utilization of biomass waste resources and facilitates the recovery of low-concentration rare earth ions from mineral waste tailings.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing ion-imprinted mesoporous materials, the method comprising the following steps:

[0009] (1) The pretreated biomass waste was hydrolyzed to obtain chiral nanocrystals;

[0010] (2) The solution containing the chiral nanocrystals described in step (1), the silane coupling agent modified with the functional monomer, the silicon source and the imprinted ion source are reacted to obtain the precursor material; then the precursor material is subjected to evaporation drying and double template removal treatment in sequence to obtain the ion-imprinted mesoporous material.

[0011] This invention employs a direct copolymerization method to prepare a dual-template chiral mesoporous silica membrane with a bio-template and surface ion imprinting for the selective adsorption of light rare earth ions. First, chiral nanocrystals are used as biomass templates with structural orientation and high specific surface area. The functional groups and monomers on the surface of the chiral nanocrystals provide chelation sites for the target rare earth ions. Through this dual-template docking directional ion imprinting technology and evaporation-induced self-assembly, the imprinted template rare earth ions interact with the structure-guided template, forming a template-template docking configuration. All ion imprinting sites are located on the surface of the ion-imprinted mesoporous membrane (IMMs), giving the mesoporous material a highly ordered pore structure and high specific surface area. Furthermore, the ion imprinting plays a specific recognition role, significantly improving the adsorption capacity and selectivity of the mesoporous material. Simultaneously, this invention uses biomass-based chiral nanocrystals as an intermediate, which has the advantages of being green, environmentally friendly, low-cost, and readily available. The preparation process is simple, does not involve high-temperature or high-pressure experimental conditions, is safe and reliable, and is conducive to large-scale production. Secondly, the ion-imprinted mesoporous material provided by this invention has the characteristics of uniform mesoporous structure, large specific surface area and good pore structure stability. Moreover, it contains a large number of coordination adsorption functional groups such as carboxyl groups and amine groups, thus exhibiting high adsorption activity and adsorption selectivity for rare earth ions in solution.

[0012] Finally, this invention provides an ion-imprinted mesoporous material as an adsorbent material, which has the advantages of high adsorption capacity, high adsorption efficiency, and the ability to accurately identify and selectively adsorb target ions. Compared with the powdered nano-adsorbent materials disclosed in the prior art, the ion-imprinted mesoporous material provided by this invention has the characteristics of convenient recycling and has broad application prospects.

[0013] Preferably, in step (1), the pretreatment includes a purification process.

[0014] Preferably, the purification process involves first soaking the biomass waste in a strong acid solution with a concentration of 1 mol / L for 10-15 hours, and then soaking it in a strong alkali solution with a concentration of 1 mol / L for 10-15 hours. This process is repeated until the biomass waste shows no obvious reaction in the strong acid and alkali solutions, after which it undergoes further treatment.

[0015] Preferably, the biomass waste includes biomass waste containing lignocellulose and / or chitin.

[0016] Preferably, the biomass waste includes any one or a combination of at least two of the following: sawdust, waste paper, crab shells, shrimp shells, or insects.

[0017] Preferably, the strong acid solution includes hydrochloric acid solution and / or sulfuric acid solution.

[0018] Preferably, the strong alkaline solution includes a sodium hydroxide solution.

[0019] Preferably, in step (1), when the biomass waste is biomass waste containing lignocellulose, the pretreatment process further includes bleaching treatment.

[0020] Preferably, in step (1), when the biomass waste is biomass waste containing chitin, the pretreatment process further includes bleaching and deacetylation treatment in sequence.

[0021] Preferably, the bleaching process includes decolorization and deodorization treatment in a solution containing a bleaching agent.

[0022] Preferably, the bleaching agent includes sodium hypochlorite and / or hydrogen peroxide.

[0023] Preferably, the bleaching agent has a mass concentration of 5 wt%.

[0024] Preferably, the decolorization and deodorization temperature is 70°C and the time is 2 hours.

[0025] Preferably, the deacetylation process includes high-temperature treatment with sodium hydroxide solution.

[0026] In this invention, the chitin nanocrystals contain a certain amount of amino groups after partial deacetylation. These groups can chelate with rare earth ions, thereby providing more imprinted active sites and further improving the adsorption capacity of the mesoporous material.

[0027] Preferably, the sodium hydroxide solution has a mass concentration of 35 wt%.

[0028] Preferably, the high-temperature treatment is performed at a temperature of 90°C for a time of 0.5-4 hours, such as 0.5 hours, 0.8 hours, 1 hour, 2 hours, 3 hours, 4 hours, etc.

[0029] Preferably, in step (1), the hydrolysis process is carried out using hydrochloric acid solution.

[0030] Preferably, the concentration of the hydrochloric acid solution is 3 mol / L.

[0031] Preferably, in step (1), the temperature of the hydrolysis treatment is 90-100℃, for example, 90℃, 92℃, 95℃, 98℃, 100℃, etc.; and the time is 1.5h.

[0032] Preferably, in step (2), the mass concentration of the solution containing the chiral nanocrystals in step (1) is 2-4 wt%, for example, it can be 2 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%, 3 wt%, 3.2 wt%, 3.5 wt%, 3.8 wt%, 4 wt%, etc.

[0033] Preferably, in step (2), the structure of the functional monomer contains amino and / or carboxyl groups, preferably a combination of amino and carboxyl groups.

[0034] In this invention, by using functional monomers with specific groups, the adsorbent has more active sites to chelate with imprinted ions, thereby increasing the adsorption capacity.

[0035] Preferably, in step (2), the functional monomer includes any one or a combination of at least two of ethylenediaminetetraacetic acid, 4-vinylpyridine, p-aminobenzoic acid, or dimethylaminoethyl methacrylate.

[0036] Preferably, in step (2), the preparation method of the silane coupling agent modified by the functional monomer includes the following steps: adjusting the pH of a solution of a functional monomer containing amino and / or carboxyl groups to alkaline, cooling it, slowly adding siloxane in batches, adjusting the pH to acidic after the reaction, and obtaining the silane coupling agent modified by the functional monomer.

[0037] Preferably, the process of adjusting the pH to alkaline involves using a sodium hydroxide solution to adjust the pH value to 11.

[0038] Preferably, the concentration of the sodium hydroxide solution is 10 mol / L.

[0039] Preferably, the cooling temperature is 0°C and the cooling time is 10 minutes.

[0040] Preferably, the siloxane is added slowly in batches twice.

[0041] Preferably, the temperature at which the siloxane is added slowly in batches is 0°C.

[0042] In this invention, siloxane is slowly added to the system in an ice bath, and the resulting solution is cooled in an ice bath for 10 minutes. When the temperature reaches 0°C, the above operation is repeated twice.

[0043] Preferably, the siloxane comprises 3-glycidyl etheroxypropyltrimethoxysilane.

[0044] Preferably, the reaction is carried out at a temperature of 65°C for 6 hours.

[0045] Preferably, the process of adjusting the pH to acidic is to adjust the pH value to 2.4 using a nitric acid solution.

[0046] Preferably, in step (2), the silicon source includes tetraethyl orthosilicate.

[0047] Preferably, in step (2), the molar ratio of the silane coupling agent modified by the functional monomer to the silicon source is (0.2-1.2):(8.8-9.8), more preferably (0.6-1.0):(9.0-9.4), for example, it can be 0.2:9.8, 0.3:9.7, 0.4:9.6, 0.5:9.5, 0.6:9.4, 0.7:9.3, 0.8:9.2, 0.9:9.1, 1:9, 1.1:8.9, 1.2:8.8, etc.

[0048] In this invention, by adjusting the molar ratio of the silane coupling agent modified by the functional monomer to the silicon source, the most active sites are obtained without affecting the imprinting of the structural template. If the molar ratio is too low, there will be a lack of active sites and thus a low adsorption capacity. Conversely, if the molar ratio is too high, the structural template will be damaged and the adsorbent will break.

[0049] Preferably, in step (2), the imprinted ion source includes La 3+ Ce 3+ Pr 3+ 、Nd 3+ 、Sm 3+ Or Eu 3+ Any one or at least two of the rare earth ions.

[0050] Preferably, in step (2), the mass of the imprinted ion source is 20-100 mg, more preferably 30-50 mg, for example, 20 mg, 30 mg, 40 mg, 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, etc.

[0051] In this invention, by adjusting the quality of the imprinted ion source, the maximum number of imprinted ions can be added without affecting the imprinting of the structural template. Low quality will result in fewer imprinted sites and thus lower adsorption capacity, while high quality will cause the structural template to precipitate.

[0052] Preferably, in step (2), the reaction temperature is 60°C and the time is 4 hours.

[0053] Preferably, in step (2), the evaporation and drying process involves pouring the precursor material into a petri dish coated with a coating and slowly evaporating it at room temperature to obtain a composite film.

[0054] Preferably, the coating comprises any one or a combination of at least two of the following: a fluorine-containing coating, a silicon-containing coating, or a paraffin-containing coating.

[0055] Preferably, in step (2), the method of removing the double template includes sulfuric acid elution and / or high-temperature calcination.

[0056] Preferably, the sulfuric acid elution process involves reacting the composite membrane in a 6 mol / L sulfuric acid solution at 80-90°C for 5-8 hours.

[0057] Preferably, the high-temperature calcination temperature is 500-600℃, for example, 500℃, 520℃, 540℃, 550℃, 580℃, 600℃, etc., the time is 5-7h, for example, 5h, 5.5h, 6h, 6.5h, 7h, and the heating rate is 5-10℃ / min, for example, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc.

[0058] In a second aspect, the present invention provides an ion-imprinted mesoporous material, which is prepared by the method for preparing ion-imprinted mesoporous materials according to the first aspect.

[0059] Thirdly, the present invention provides a rare earth ion adsorption material, the rare earth ion adsorption material comprising the ion-imprinted mesoporous material according to the second aspect.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] This invention provides a method for preparing ion-imprinted mesoporous materials. It employs a direct copolymerization method to prepare a dual-template chiral phase mesoporous silica membrane with a bio-template and surface ion imprinting, for the selective adsorption of light rare earth ions. First, chiral nanocrystals are used as biomass templates with structural orientation and high specific surface area. The functional groups and monomers on the surface of the chiral nanocrystals provide chelation sites with the target rare earth ions. Through this dual-template docking directional ion imprinting technology and evaporation-induced self-assembly, the imprinted template rare earth ions interact with the structure-guided template, forming a template-template docking configuration. All ion imprinting sites are located on the surface of the ion-imprinted mesoporous membrane (IMMs), giving the mesoporous material a highly ordered pore structure and high specific surface area. Furthermore, the ion imprinting plays a specific recognition role, significantly improving the adsorption capacity and selectivity of the mesoporous material. Simultaneously, this invention uses biomass-based chiral nanocrystals as an intermediate, which has the advantages of being green, environmentally friendly, low-cost, and readily available. The preparation process is simple, does not involve high-temperature or high-pressure experimental conditions, is safe and reliable, and is conducive to large-scale production. Secondly, the ion-imprinted mesoporous material provided by this invention has the characteristics of uniform mesoporous structure, large specific surface area, adjustable pore structure and good stability. Moreover, it contains a large number of coordination adsorption functional groups such as carboxyl and amine groups, thus exhibiting high adsorption activity and adsorption selectivity for rare earth ions in solution.

[0062] Finally, this invention provides an ion-imprinted mesoporous material as an adsorbent material, which has the advantages of high adsorption capacity (>100 mg / g), high adsorption efficiency, and the ability to accurately identify and selectively adsorb target ions (SF(REE)). 3+ / Fe 3 + )>30, SF(REE 3+ / Al 3+ )>40, SF(REE 3+ / Cu 2+ )>100, SF(REE) 3+ / Mg 2+ Compared with the powdered nano-adsorbent materials disclosed in the prior art, the ion-imprinted mesoporous material provided by the present invention has the characteristics of convenient recycling and has broad application prospects. Attached Figure Description

[0063] Figure 1 Scanning electron microscope image of the cross-sectional structure of the chiral nanocrystalline hard template provided by the present invention;

[0064] Figure 2 Cross-sectional scanning electron microscope images of ion-imprinted mesoporous materials with different pore structures provided by the present invention. Detailed Implementation

[0065] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0066] Example 1

[0067] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0068] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 0.5h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialyzing for 5 days, it was sonicated, and the solid content was measured. The chiral nanocrystals were then stored in a refrigerator.

[0069] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0), and 30 mg of imprinted neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) were placed in a three-necked flask, heated to 60 °C, and stirred vigorously for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0070] Chiral nanocrystals can be stably dispersed in aqueous solutions. When the solvent slowly evaporates, the rod-shaped chiral nanocrystals undergo self-assembly under the influence of intermolecular forces, forming a chiral phase sequence structure through evaporation-induced self-assembly. A cross-sectional scanning electron microscope image of the chiral nanocrystals is shown below. Figure 1 As shown. A cross-sectional scanning electron microscope image of the ion-imprinted mesoporous material is shown below. Figure 2 As shown, the originally dense silica film has a highly ordered pore structure and a high specific surface area, indicating that the chiral nanocrystalline hard template can be successfully imprinted on the silica film.

[0071] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0072]

[0073] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0074] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu 2+ Fe 3+ Al 3+ The concentration of Nd in the solution was 200 ppm. After adsorption at room temperature for 24 h, the remaining Nd in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0075]

[0076]

[0077] Where: K d This is the distribution coefficient, in ml·g. -1 q eC represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0078] Example 2

[0079] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0080] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 1h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, the solid content was measured, and it was stored in a refrigerator to obtain chiral nanocrystals.

[0081] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate 0.8:9.2), and 30 mg of imprinted neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) were placed in a three-necked flask, heated to 60 °C, and stirred vigorously for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0082] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0083]

[0084] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0085] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu2+ Fe 3+ Al 3+ The concentration of Nd in the solution was 100 ppm. After adsorption at room temperature for 24 h, the residual Nd in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0086]

[0087]

[0088] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0089] Example 3

[0090] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0091] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 2h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialyzing for 5 days, it was sonicated, and the solid content was measured. The chiral nanocrystals were then stored in a refrigerator.

[0092] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (the molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate was 0.6:9.4), and 30 mg of imprinted neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) were placed in a three-necked flask, heated to 60 °C, and stirred vigorously for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0093] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0094]

[0095] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0096] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu2+ Fe 3+ Al 3+ The concentration of Nd in the solution was 100 ppm. After adsorption at room temperature for 24 h, the residual Nd in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0097]

[0098]

[0099] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0100] Example 4

[0101] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0102] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 2.5h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, and the solid content was measured. The chiral nanocrystals were then stored in a refrigerator.

[0103] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution; 10 mL of a solution containing the chiral nanocrystals described in step (1), 3 wt% of the mass concentration, 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (the molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate was 1.0:9.0) and 40 mg of imprinted Nd ions were added. 3+ The mixture was placed in a three-necked flask, heated at 60°C and stirred vigorously for 4 hours. After the reaction was completed, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540°C for 6 hours to obtain an ion-imprinted mesoporous material.

[0104] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0105]

[0106] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0107] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu 2+Fe 3+ Al 3+ The content of all were 200 ppm. After adsorption at room temperature for 24 h, the remaining Eu in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0108]

[0109]

[0110] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0111] Example 5

[0112] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0113] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 4h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, the solid content was measured, and it was stored in a refrigerator to obtain chiral nanocrystals.

[0114] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0), and 50 mg of imprinted neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) were placed in a three-necked flask, heated to 60 °C, and stirred vigorously for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0115] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0116]

[0117] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0118] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu2+ Fe 3+ Al 3+ The concentration of Nd in the solution was 100 ppm. After adsorption at room temperature for 24 h, the residual Nd in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0119]

[0120]

[0121] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0122] Example 6

[0123] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0124] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 4h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, the solid content was measured, and it was stored in a refrigerator to obtain chiral nanocrystals.

[0125] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0), and 100 mg of imprinted neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) were placed in a three-necked flask, heated to 60 °C, and vigorously stirred for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0126] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Nd... 3+ The adsorption performance test included the following steps: A solution of neodymium nitrate hexahydrate (Nd(NO3)3·6H2O) with a concentration of 200 mg / L was prepared. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the neodymium nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining Nd in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0127]

[0128] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0129] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions were Nd... 3+ and competing ions Ca 2+ Mg 2+ Cu2+ Fe 3+ Al 3+ The concentration of Nd in the solution was 100 ppm. After adsorption at room temperature for 24 h, the residual Nd in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0130]

[0131]

[0132] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0133] Example 7

[0134] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0135] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to remove protein. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 4h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, the solid content was measured, and it was stored in a refrigerator to obtain chiral nanocrystals.

[0136] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (the molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate was 1.0:9.0), and 30 mg of imprinted ion-imprinted lanthanum nitrate hexahydrate La(NO3)3·6H2O were placed in a three-necked flask, heated to 60 °C, and stirred vigorously for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0137] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for La 3+ The adsorption performance test included the following steps: Lanthanum nitrate hexahydrate La(NO3)3·6H2O was prepared into a solution with a concentration of 200 mg / L. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the lanthanum nitrate solution. After adsorption for 24 h at room temperature, a sample was taken to determine the remaining La in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0138]

[0139] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0140] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions La 3+ and competing ions Ca 2+ Mg 2+ Cu 2+Fe 3+ Al 3+ The content of all substances was 100 ppm. After adsorption at room temperature for 24 h, samples were taken to determine the remaining La in the solution. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0141]

[0142]

[0143] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0144] Example 8

[0145] This embodiment provides an ion-imprinted mesoporous material and its preparation method, the method comprising the following steps:

[0146] (1) First, 10g of chitin was soaked in a 1mol / L hydrochloric acid solution for 12h to desalt it, and then soaked in a 1mol / L sodium hydroxide solution for 12h to deproteinize it. This operation was repeated three times. After desalting and deproteinizing, the chitin was decolorized and deodorized in a 1% sodium chlorite solution at 70℃ for 2h; then partially deacetylated in a 35wt% sodium hydroxide solution with a chitin to sodium hydroxide solution mass ratio of 1:25, a reaction temperature of 90℃, and a reaction time of 4h. After each step, the chitin was washed with deionized water until neutral and filtered. Then, it was hydrolyzed with hydrochloric acid with a chitin to hydrochloric acid solution mass ratio of 1:30, a reaction temperature of 90℃, and a reaction time of 1.5h. After the reaction, the chitin was washed with deionized water until neutral and centrifuged. After dialysis for 5 days, it was sonicated, and the solid content was measured. The chiral nanocrystals were then stored in a refrigerator.

[0147] (2) Dissolve 4.25 g iminodiacetic acid in 50 mL of deionized water, and adjust the pH of the solution to 11 from a 10 mol / L sodium hydroxide solution. Slowly add 1.4 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the system in an ice bath, and continue the reaction at 65 °C for 6 h. After cooling the resulting solution in an ice bath for 10 min, when the temperature drops to 0 °C, slowly add 1.6 mL of 3-glycidyl etheroxypropyltrimethoxysilane to the above solution, and raise the temperature to continue the reaction for 6 h. Following the same procedure as described above, 1.7 mL of 3-glycidyl etheroxypropyltrimethoxysilane was added again, and the pH of the prepared silane coupling agent solution modified with functional monomers was adjusted to 2.4 with nitric acid solution. A solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL of iminodiacetic acid-modified silane coupling agent, 0.4 mL of tetraethyl orthosilicate (the molar ratio of iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate was 1.0:9.0), and 30 mg of imprinted europium nitrate hexahydrate Eu(NO3)3·6H2O were placed in a three-necked flask, heated to 60 °C, and vigorously stirred for 4 h. After the reaction was complete, the mixture was poured into a polytetrafluoroethylene petri dish, and the solution was evaporated at room temperature to obtain a composite membrane. The composite membrane was then calcined at 540 °C for 6 h to obtain an ion-imprinted mesoporous material.

[0148] The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent for Eu... 3+ The adsorption performance test included the following steps: Europium nitrate hexahydrate Eu(NO3)3·6H2O was prepared into a solution with a concentration of 200 mg / L. 10 mg of the above ion-imprinted mesoporous material was placed in 10 mL of the europium nitrate solution. After adsorption at room temperature for 24 h, a sample was taken to determine the remaining Eu in the solution. 3+ The concentration is then used to calculate the adsorption capacity according to formula (1):

[0149]

[0150] In the formula: Q e C is the sample adsorption capacity, C0 is the initial concentration of rare earth ions, and C... e V represents the remaining concentration of rare earth ions after adsorption, V is the volume of the rare earth ion solution, and M is the relative atomic mass of the rare earth ions.

[0151] The ion-imprinted mesoporous material provided in this embodiment was used as an adsorbent to test the adsorption performance of different rare earth ions, including the following steps: 10 mg of the above-mentioned ion-imprinted mesoporous material was placed in 10 mL of a rare earth solution containing competing ions, wherein the rare earth ions Eu... 3+ and competing ions Ca 2+ Mg 2+ Cu 2+Fe 3+ Al 3+ The content of all were 100 ppm. After adsorption at room temperature for 24 h, the remaining Eu in the solution was measured. 3+ The concentrations of competing ions were used, and the adsorption capacity and selectivity were calculated using formulas (1), (2), and (3):

[0152]

[0153]

[0154] Where: K d This is the distribution coefficient, in ml·g. -1 q e C represents the sample adsorption capacity. e K represents the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, and K is the concentration of rare earth ions after adsorption. d1 K d2 Ki for adsorbing the target ion and the competing ion, respectively. d .

[0155] Example 9

[0156] The difference between this embodiment and Example 1 is that the molar ratio of the iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate is 0.1:9.9, while all other aspects are the same as in Example 1.

[0157] Example 10

[0158] The difference between this embodiment and Example 1 is that the molar ratio of the iminodiacetic acid-modified silane coupling agent to tetraethyl orthosilicate is 2:8, while all other aspects are the same as in Example 1.

[0159] Example 11

[0160] The difference between this embodiment and Example 1 is that the iminodiacetic acid-modified silane coupling agent is replaced with a 4-vinylpyridine-modified silane coupling agent; all other aspects are the same as in Example 1.

[0161] Example 12

[0162] The difference between this embodiment and embodiment 1 is that in step (2), Nd 3+ The mass of the imprinted ion source was 10 mg, and everything else was the same as in Example 1.

[0163] Example 13

[0164] The difference between this embodiment and embodiment 1 is that in step (2), Nd 3+ The mass of the imprinted ion source was 110 mg, and everything else was the same as in Example 1.

[0165] Comparative Example 1

[0166] The difference between this comparative example and Example 1 is that the iminodiacetic acid-modified silane coupling agent is replaced with an equal amount of unmodified silane coupling agent; otherwise, they are the same as in Example 1.

[0167] Comparative Example 2

[0168] The difference between this comparative example and Example 1 is that chitosan nanocrystals are replaced with an equal amount of cellulose nanocrystals; otherwise, they are the same as in Example 1.

[0169] Comparative Example 3

[0170] The difference between this comparative example and Example 1 is that Nd is not added. 3+ The imprinted ion source and everything else are the same as in Example 1.

[0171] Test conditions

[0172] The concentrations of the residual rare earth ion solutions after adsorption provided in Examples 1 to 13 and Comparative Examples 1 to 3 were tested using the following methods:

[0173] Dilute 1 mL of the remaining rare earth ion solution after adsorption with deionized water by 5 times. Similarly, dilute 1 mL of the rare earth ion solution before adsorption by 5 times and test its ion concentration using ICP.

[0174] The test results are shown in Table 1:

[0175] Table 1

[0176]

[0177] As can be seen from Table 1, the following conclusions can be drawn:

[0178] (1) Due to the influence of competing ions, the adsorption capacity of the ion-imprinted mesoporous material provided by this invention for target ions in systems containing competing ions decreases. In multi-element solutions, competition between ions for active functional groups present on the surface of the adsorbent is one of the factors that significantly affects the reduction of adsorption capacity.

[0179] (2) As can be seen from the comparison of Examples 1-6, Examples 9-10, and Examples 12-13, the present invention achieves an adsorption capacity higher than 100 mg / g by controlling the molar ratio of the silane coupling agent modified with a specific type of functional monomer to the silicon source to the preferred range of (0.6-1.0):(9.0-9.4), and simultaneously controlling the mass of the imprinted ion source to the preferred range of 30-50 mg. -1 If the adsorption exceeds the above-mentioned preferred range, the adsorption capacity of the material will decrease and the selectivity will also deteriorate.

[0180] (3) As can be seen from the comparison between Example 1 and Example 11, iminodiacetic acid is the most suitable for adsorbing Nd compared with other functional monomers. 3+ Functional monomers.

[0181] (4) As can be seen from the comparison of Examples 1, 7 and 8, iminodiacetic acid is the most suitable for adsorbing Nd compared with other rare earth ions. 3+ Functional monomers.

[0182] (5) As can be seen from the comparison between Example 1 and Comparative Example 2, chitin nanocrystals, as a hard template material, contain a certain amount of amine groups, which can provide more imprinting sites, and therefore have a significant advantage in adsorption capacity.

[0183] (6) As can be seen from the comparison between Example 1 and Comparative Example 3, without the addition of Nd 3+ The non-ionic imprinted mesoporous membranes prepared by imprinted ion sources exhibit a significant decrease in adsorption selectivity.

[0184] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an ion-imprinted chiral mesoporous material for rare earth ion adsorption, characterized in that, The method includes the following steps: (1) The pretreated biomass waste was hydrolyzed to obtain chiral nanocrystals; (2) The solution containing the chiral nanocrystals described in step (1), the silane coupling agent modified with the functional monomer, the silicon source and the imprinted ion source are reacted to obtain the precursor material; then the precursor material is subjected to evaporation drying and double template removal treatment in sequence to obtain the ion-imprinted chiral mesoporous material. The biomass waste mentioned in step (1) includes biomass waste containing chitin, and the pretreatment process further includes bleaching and deacetylation treatment in sequence; In step (2), the molar ratio of the silane coupling agent modified with the functional monomer to the silicon source is (0.6-1.0):(9.0-9.4). The functional monomer includes any one or a combination of at least two of ethylenediaminetetraacetic acid, 4-vinylpyridine, p-aminobenzoic acid, or dimethylaminoethyl methacrylate. The imprinted ion source includes La 3+ Ce 3+ Pr 3+ 、Nd 3+ 、Sm 3 + Or Eu 3+ The imprinted ion source contains any one or at least two of the rare earth ions, and the mass of the imprinted ion source is 30-50 mg. All ion-imprinted sites of the ion-imprinted chiral mesoporous material are located on the surface.

2. The method according to claim 1, characterized in that, In step (1), the pretreatment includes a purification process.

3. The method according to claim 2, characterized in that, The purification process involves first soaking the biomass waste in a 1 mol / L strong acid solution for 10-15 hours, and then soaking it in a 1 mol / L strong alkali solution for 10-15 hours, and repeating the above operation.

4. The method according to claim 1, characterized in that, The biomass waste includes any one or a combination of at least two of the following: crab shells, shrimp shells, or insects.

5. The method according to claim 3, characterized in that, The strong acid solution includes hydrochloric acid solution and / or sulfuric acid solution.

6. The method according to claim 3, characterized in that, The strong alkaline solution includes sodium hydroxide solution.

7. The method according to claim 1, characterized in that, The bleaching process includes decolorization and deodorization in a solution containing bleaching agents.

8. The method according to claim 7, characterized in that, The bleaching agent includes sodium hypochlorite and / or hydrogen peroxide.

9. The method according to claim 7, characterized in that, The bleaching agent has a mass concentration of 5 wt%.

10. The method according to claim 7, characterized in that, The decolorization and deodorization process is carried out at a temperature of 70°C for 2 hours.

11. The method according to claim 1, characterized in that, The deacetylation process includes high-temperature treatment with sodium hydroxide solution.

12. The method according to claim 11, characterized in that, The sodium hydroxide solution has a mass concentration of 35 wt%.

13. The method according to claim 11, characterized in that, The high-temperature treatment is performed at a temperature of 90°C for a duration of 0.5-4 hours.

14. The method according to claim 1, characterized in that, In step (1), the hydrolysis process is carried out by hydrolysis using hydrochloric acid solution.

15. The method according to claim 14, characterized in that, The concentration of the hydrochloric acid solution is 3 mol / L.

16. The method according to claim 1, characterized in that, In step (1), the hydrolysis treatment is carried out at a temperature of 90-100℃ for 1.5 hours.

17. The method according to claim 1, characterized in that, In step (2), the mass concentration of the solution containing the chiral nanocrystals in step (1) is 2-4 wt%.

18. The method according to claim 1, characterized in that, In step (2), the preparation method of the silane coupling agent modified by the functional monomer includes the following steps: adjusting the pH of the solution containing the functional monomer to alkaline, cooling and slowly adding siloxane in batches, adjusting the pH to acidic after the reaction, and obtaining the silane coupling agent modified by the functional monomer.

19. The method according to claim 18, characterized in that, The process of adjusting the pH to alkaline involves using a sodium hydroxide solution to adjust the pH value to 11.

20. The method according to claim 19, characterized in that, The concentration of the sodium hydroxide solution is 10 mol / L.

21. The method according to claim 18, characterized in that, The cooling temperature was 0°C and the time was 10 minutes.

22. The method according to claim 18, characterized in that, The siloxane was added slowly in batches twice.

23. The method according to claim 18, characterized in that, The temperature at which the siloxane is added slowly in batches is 0°C.

24. The method according to claim 18, characterized in that, The siloxane includes 3-glycidyl etheroxypropyltrimethoxysilane.

25. The method according to claim 18, characterized in that, The reaction was carried out at a temperature of 65°C for 6 hours.

26. The method according to claim 18, characterized in that, The process of adjusting the pH to acidic is to use a nitric acid solution to adjust the pH value to 2.

4.

27. The method according to claim 1, characterized in that, In step (2), the silicon source includes tetraethyl orthosilicate.

28. The method according to claim 1, characterized in that, In step (2), the reaction temperature is 60°C and the time is 4 hours.

29. The method according to claim 1, characterized in that, In step (2), the evaporation and drying process involves pouring the precursor material into a petri dish coated with a coating and evaporating it at room temperature to obtain a composite film.

30. The method according to claim 29, characterized in that, The coating includes any one or a combination of at least two of the following: a fluorine-containing coating, a silicon-containing coating, or a paraffin-containing coating.

31. The method according to claim 1, characterized in that, In step (2), the method of removing the double template includes sulfuric acid elution and / or high-temperature calcination.

32. The method according to claim 31, characterized in that, The sulfuric acid elution process involves reacting the composite membrane in a 6 mol / L sulfuric acid solution at 80-90°C for 5-8 hours.

33. The method according to claim 31, characterized in that, The high-temperature calcination is carried out at a temperature of 500-600℃ for 5-7 hours, with a heating rate of 5-10℃ / min.

34. An ion-imprinted chiral mesoporous material for rare earth ion adsorption, characterized in that, The ion-imprinted chiral mesoporous material is prepared by the method for preparing ion-imprinted chiral mesoporous materials according to any one of claims 1-33.

35. A rare earth ion adsorption material, characterized in that, The rare earth ion adsorption material includes the ion-imprinted chiral mesoporous material according to claim 34.

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