CN117531490A - Imprinted mesoporous material for rare earth ion adsorption and preparation method thereof - Google Patents

Abstract

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

Description

An imprinted mesoporous material for rare earth ion adsorption and its preparation method

Technical field

The invention belongs to the technical field of adsorbent materials, and specifically relates to an imprinted mesoporous material for rare earth ion adsorption and a preparation method thereof.

Background technique

Rare earth ions include lanthanide ions and seventeen kinds of ions such as scandium and yttrium of the third subgroup. Due to their unique optical, electrical and magnetic properties, they are considered to be important for the development of wind turbines, electric vehicle engines, and medicine. One of the important strategic resources in areas such as diagnostics and refining. However, there are some problems in resource utilization and recovery of rare earth ions. For example, the ammonium bicarbonate precipitation transformation process used in the existing technology cannot effectively recover low-concentration rare earth ions in the in-situ leaching leachate, resulting in serious rare earth loss and water pollution.

Currently, reported methods for recovering metal ions from low-concentration metal ion wastewater mainly include chemical precipitation, extraction, ion exchange, membrane separation, and adsorption. Among them, the adsorption method has the characteristics of good separation effect, simple operation, no need for external assistance, low energy consumption, and the ability to selectively adsorb, separate, classify and enrich low-concentration metal ions in wastewater by selecting different adsorbents. It is considered to be the most feasible method to recover and separate low-concentration metal ions. In recent years, researchers have mostly used adsorbents containing natural minerals, oxides, nanocomposites or microorganisms to adsorb metal ions.

Although the above-mentioned rare earth ion adsorbents have made some progress in improving the maximum adsorption capacity and desorption rate, there are still problems of low adsorption capacity and poor selectivity in treating low-concentration rare earth wastewater. In order to solve the above problems, researchers usually use physical methods or chemical methods. Physical methods are specifically the use of mesoporous materials with highly ordered pore structures and high specific surface areas, which can effectively increase the adsorption capacity. Most of the mesoporous materials disclosed in the prior art are synthesized using the template method, among which there are many studies related to the soft template method. The soft template method mostly uses surfactants, but it is not conducive to environmental protection. There are not many studies on the hard template method. According to existing literature reports, mesoporous materials can be prepared using environmentally friendly cellulose nanocrystals as hard templates. However, currently, the control of pore structure and its high adsorption capacity based on mesoporous membranes, The goal of high selectivity has not yet been achieved.

Therefore, there is an urgent need to develop an adsorbent material with high adsorption capacity and high selectivity to solve the above problems.

Contents of the invention

In view of the shortcomings of the existing technology, the object of the present invention is to provide an imprinted mesoporous material for rare earth ion adsorption and a preparation method thereof. The present invention uses the chiral nematic arrangement structure of biomass nanocrystals as a hard template and rare earth ions as imprinting site templates to prepare efficient independent ion-imprinted mesoporous films (referred to as IMMs), which meet the requirements of high adsorption. While meeting the demand for capacity and high selectivity, it achieves effective utilization of biomass waste resources and is conducive to the recovery of low-concentration rare earth ions in mineral waste tailings.

In order to achieve the purpose of this invention, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a method for preparing ion-imprinted mesoporous materials, which method includes the following steps:

(1) Hydrolyze the pretreated biomass waste to obtain chiral nanocrystals;

(2) React 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 to obtain a precursor material; and then use the precursor material The material is sequentially subjected to evaporation drying and de-double template processing to obtain the ion-imprinted mesoporous material.

The present invention adopts a direct copolymerization method to prepare a biological template-surface ion imprinted dual-template chiral phase-separated mesoporous silica membrane, which is used 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 surface functional groups and functional monomers of chiral nanocrystals jointly provide sites for chelating target rare earth ions. Through this dual-template docking directed ion imprinting technology and evaporation-induced self-assembly, the imprinted template rare earth ions interact with the structure-guided template to form a template-template docking configuration, and all ion imprinted sites are located on the surface of ion-imprinted mesoporous membranes (IMMs) , so that mesoporous materials have highly ordered pore structures and high specific surface areas, and ion imprinting plays a role in specific recognition, thereby significantly improving the adsorption capacity and adsorption selectivity of mesoporous materials. At the same time, the present invention uses biomass-based chiral nanocrystals as intermediates, which have the advantages of being green, environmentally friendly, low-cost, and easy to obtain. The preparation process is simple to operate, does not involve high-temperature and high-pressure experimental conditions, is safe and reliable, and is conducive to large-scale Production. Secondly, the ion-imprinted mesoporous material provided by the present invention has the characteristics of uniform mesoporous structure, large specific surface area and good pore structure stability, and it contains a large number of carboxyl groups, amine groups and other coordination adsorption functional groups, so that it can The rare earth ions show high adsorption activity and adsorption selectivity.

Finally, the present invention provides an ion-imprinted mesoporous material as an adsorption material, which has the advantages of adsorption capacity, high adsorption efficiency, and the ability to accurately identify target ions and selectively adsorb them. It is different from the powdery nano-adsorption materials disclosed in the prior art. Compared with other materials, the ion-imprinted mesoporous material provided by the present invention has the characteristics of convenient recycling and has broad application prospects.

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

Preferably, the purification process is to first soak the biomass waste in a strong acid solution with a concentration of 1 mol/L for 10-15 hours, and then soak it in a strong alkali solution with a concentration of 1 mol/L for 10-15 hours, and repeat the above operations. , until the biomass waste has no obvious reaction in the strong acid and alkali solution, and then perform subsequent processing.

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

Preferably, the biomass waste includes any one or a combination of at least two of wood chips, waste paper, crab shells, shrimp shells or insects.

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

Preferably, the strong alkaline solution includes sodium hydroxide solution.

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

Preferably, in step (1), when the biomass waste is biomass waste containing chitin, the pretreatment process also includes bleaching and deacetylation in sequence.

Preferably, the bleaching process includes decolorizing and deodorizing in a solution containing a bleaching reagent.

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

Preferably, the mass concentration of the bleaching reagent is 5wt%.

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

Preferably, the deacetylation process includes high-temperature treatment using sodium hydroxide solution.

In the present 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 of mesoporous materials. capacity.

Preferably, the mass concentration of the sodium hydroxide solution is 35wt%.

Preferably, the temperature of the high-temperature treatment is 90°C and the time is 0.5-4h, for example, it can be 0.5h, 0.8h, 1h, 2h, 3h, 4h, etc.

Preferably, in step (1), the hydrolysis treatment process is to use hydrochloric acid solution for hydrolysis treatment.

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

Preferably, in step (1), the temperature of the hydrolysis treatment is 90-100°C, for example, it can be 90°C, 92°C, 95°C, 98°C, 100°C, etc.; the time is 1.5 h.

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

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

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

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

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 the solution of the functional monomer containing amino and/or carboxyl groups to alkaline, cooling Siloxane is then slowly added in batches, and the pH is adjusted to acidic after the reaction to obtain the silane coupling agent modified by the functional monomer.

Preferably, the process of adjusting the pH to alkaline is to use sodium hydroxide solution to adjust the pH value to 11.

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

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

Preferably, the number of times of slowly adding silicone in batches is twice.

Preferably, the temperature at which the silicone is slowly added in batches is 0°C.

In the present 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 becomes 0°C, the above operation is repeated twice.

Preferably, the silicone includes 3-glycidoxypropyltrimethoxysilane.

Preferably, the reaction temperature is 65°C and the reaction time is 6 hours.

Preferably, the process of adjusting the pH to acidity is to use a nitric acid solution to adjust the pH value to 2.4.

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

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), 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.

In the present invention, by regulating the molar ratio of the silane coupling agent modified by the functional monomer to the silicon source, the most active sites can be obtained without affecting the imprinting of the structural template. If the molar ratio is too low, active sites will be lacking. This will lead to low adsorption capacity, otherwise the structural template will be damaged and the adsorbent will break.

Preferably, in step (2), the imprinted ion source includes any one or at least two of La ³⁺ , Ce ³⁺ , Pr ³⁺ , Nd ³⁺ , Sm ³⁺ or Eu ³⁺ rare earth ions. combination.

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

In the present invention, by regulating the quality of the imprinted ion source, the most imprinted ions can be added without affecting the imprinting of the structural template. Low quality will lead to fewer imprinting sites and thus low adsorption capacity, and conversely will cause the structural template to precipitate. .

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

Preferably, in step (2), the evaporation and drying process is to pour the precursor material into a petri dish with a coating on the surface, and slowly evaporate at room temperature to obtain a composite film.

Preferably, the coating includes any one or a combination of at least two of fluorine-containing coatings, silicon-containing coatings or paraffin-containing coatings.

Preferably, in step (2), the dual-template removal treatment includes sulfuric acid elution and/or high-temperature calcination.

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

Preferably, the temperature of the high-temperature calcination is 500-600°C, for example, it can be 500°C, 520°C, 540°C, 550°C, 580°C, 600°C, etc., and the time is 5-7h, for example, it can be 5h, 5.5h , 6h, 6.5h, 7h, the heating rate is 5-10℃/min, for example, it can be 5℃/min, 6℃/min, 7℃/min, 8℃/min, 9℃/min, 10℃/min wait.

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

In a third aspect, the present invention provides a rare earth ion adsorption material, which includes the ion-imprinted mesoporous material according to the second aspect.

Compared with the existing technology, the present invention has the following beneficial effects:

The invention provides a method for preparing ion-imprinted mesoporous materials, which uses a direct copolymerization method to prepare a biological template-surface ion-imprinted dual-template chiral phase array mesoporous silica membrane for the selectivity of light rare earth ions. Adsorption. First, chiral nanocrystals are used as biomass templates with structural orientation and high specific surface area. The surface functional groups and functional monomers of chiral nanocrystals jointly provide sites for chelating target rare earth ions. Through this dual-template docking directed ion imprinting technology and evaporation-induced self-assembly, the imprinted template rare earth ions interact with the structure-guided template to form a template-template docking configuration, and all ion imprinted sites are located on the surface of ion-imprinted mesoporous membranes (IMMs) , so that mesoporous materials have highly ordered pore structures and high specific surface areas, and ion imprinting plays a role in specific recognition, thereby significantly improving the adsorption capacity and adsorption selectivity of mesoporous materials. At the same time, the present invention uses biomass-based chiral nanocrystals as intermediates, which have the advantages of being green, environmentally friendly, low-cost, and easy to obtain. The preparation process is simple to operate, does not involve high-temperature and high-pressure experimental conditions, is safe and reliable, and is conducive to large-scale Production. Secondly, the ion-imprinted mesoporous material provided by the present invention has the characteristics of uniform mesoporous structure, large specific surface area, adjustable pore structure and good stability according to needs, and it contains a large number of carboxyl, amine and other coordination adsorption functional groups. , thus showing higher adsorption activity and adsorption selectivity for rare earth ions in the solution.

Finally, the present invention provides an ion-imprinted mesoporous material as an adsorption material, which has the advantages of adsorption capacity (>100 mg/g), high adsorption efficiency, and the ability to accurately identify target ions and selectively adsorb them (SF(REE ³⁺ /Fe ^{3 +} )>30, SF (REE ³⁺ /Al ³⁺ )>40, SF (REE ³⁺ /Cu ²⁺ )>100, SF (REE ³⁺ /Mg ²⁺ )>100), and now Compared with the powdery nano-adsorption 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.

Description of drawings

Figure 1 is a scanning electron microscope image of the cross-sectional structure of the chiral nanocrystal hard template provided by the present invention;

Figure 2 is a cross-sectional scanning electron microscope image of ion-imprinted mesoporous materials with different pore structures provided by the present invention.

Detailed ways

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 are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

Example 1

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 0.5h; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 30 mg of imprinted ion neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) are placed in a three-necked flask at 60°C. Heat and stir vigorously for 4h. After the reaction, 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.

Chiral nanocrystals can be stably dispersed in aqueous solutions. When the solvent evaporates slowly, rod-shaped chiral nanocrystals self-assemble due to the influence of intermolecular forces. That is, evaporation induces self-assembly to form a chiral nematic sequence structure. The cross-sectional scanning electron microscope image of the chiral nanocrystal is shown in Figure 1. The cross-sectional scanning electron microscope image of the ion-imprinted mesoporous material is shown in Figure 2, which shows that the originally dense silica film has a highly ordered pore structure and high specific surface area, indicating that the chiral nanocrystalline hard template can be successfully used in the silica film. Imprinted on top.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competing ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 200 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the remaining Nd ³⁺ and competitive ion concentrations in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 2

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. The chitin after removing salt and protein is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated with a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 1 hour; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 0.8:9.2) and 30 mg of imprinted ion neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) are placed in a three-necked flask at 60°C. Heat and stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competitive ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the remaining Nd ³⁺ and competitive ion concentrations in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 3

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 2 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 0.6:9.4) and 30 mg of imprinted ion neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) are placed in a three-necked flask at 60°C. Heat and stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competitive ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the remaining Nd ³⁺ and competitive ion concentrations in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 4

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 2.5 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 40 mg of imprinted ion Nd ³⁺ are placed in a three-necked flask, heated at 60°C and stirred vigorously for 4 hours. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competing ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 200 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the concentration of Eu ³⁺ and competing ions remaining in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 5

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 4 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 50 mg of imprinted ion neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) are placed in a three-necked flask at 60°C. Heat and stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competitive ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the remaining Nd ³⁺ and competitive ion concentrations in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 6

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 4 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 100 mg of imprinted ion neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) are placed in a three-necked flask at 60°C. Heat and stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Nd ³⁺ adsorption performance includes the following steps: prepare neodymium nitrate hexahydrate (Nd(NO ₃ ) ₃ ·6H ₂ O) to a concentration of 200 mg/L Solution, take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of neodymium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Nd ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Nd ³ The contents of ⁺ and competitive ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the remaining Nd ³⁺ and competitive ion concentrations in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 7

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. After removing salt and protein, the chitin is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated by a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 4 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 30 mg of imprinted ion lanthanum nitrate hexahydrate La(NO ₃ ) ₃ ·6H ₂ O are placed in a three-necked flask, heated at 60°C and Stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the La ³⁺ adsorption performance includes the following steps: Prepare a solution with a concentration of 200 mg/L of lanthanum nitrate hexahydrate La(NO ₃ ) ₃ ·6H ₂ O , take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of lanthanum nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining La ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion La ³ The contents of ⁺ and competing ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to determine the concentration of La ³⁺ and competing ions remaining in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 8

This embodiment provides an ion-imprinted mesoporous material and a preparation method thereof. The method includes the following steps:

(1) First soak 10g of chitin in a hydrochloric acid solution with a concentration of 1 mol/L for 12 hours to desalt, and then soak in a 1 mol/L sodium hydroxide solution for 12 hours to deproteinize, and repeat this operation three times. The chitin after removing salt and protein is decolorized and deodorized in a sodium chlorite solution with a mass concentration of 1% at 70°C for 2 hours; it is then partially deacetylated with a sodium hydroxide solution with a mass concentration of 35wt%, and the chitin and hydrogen The mass ratio of the sodium oxide solution is 1:25, the reaction temperature is 90°C, and the reaction time is 4 hours; after each of the above steps, wash with deionized water until neutral and filter with suction. After further hydrolysis with hydrochloric acid, the mass ratio of chitin to hydrochloric acid solution is 1:30, the reaction temperature is 90°C, and the reaction time is 1.5h. After the reaction is completed, it is washed with deionized water to neutrality and centrifuged. After dialysis for 5 days, the result is measured by ultrasound. The solid content is then stored in the refrigerator to obtain chiral nanocrystals;

(2) Dissolve 4.25g iminodiacetic acid in 50mL deionized water, and adjust the pH value of the solution from a sodium hydroxide solution with a concentration of 10mol/L to 11. Slowly add 1.4 mL of 3-glycidyl etheroxypropyl trimethoxysilane into the system in the ice bath. After continuing the reaction at 65°C for 6 hours, the resulting solution is cooled in the ice bath for 10 min. When the temperature becomes 0°C , then slowly add 1.6 mL of 3-glycidoxypropyltrimethoxysilane to the above solution, and increase the temperature to continue the reaction for 6 hours. Perform the same operation as above, add 1.7 mL of 3-glycidoxypropyltrimethoxysilane again, and adjust the pH value of the prepared functional monomer-modified silane coupling agent solution to 2.4 with nitric acid solution; The solution containing the chiral nanocrystals described in step (1) (10 mL, mass concentration 3 wt%), 0.429 mL iminodiacetic acid-modified silane coupling agent, 0.4 mL tetraethyl orthosilicate (iminodiacetic acid The molar ratio of acetic acid-modified silane coupling agent to tetraethyl orthosilicate is 1.0:9.0) and 30 mg of imprinted ion hexahydrate europium nitrate Eu(NO ₃ ) ₃ ·6H ₂ O were placed in a three-necked flask, heated at 60°C and Stir vigorously for 4h. After the reaction, 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.

Using the ion-imprinted mesoporous material provided in this example as an adsorbent to test the Eu ³⁺ adsorption performance includes the following steps: prepare europium nitrate hexahydrate Eu(NO ₃ ) ₃ ·6H ₂ O into a solution with a concentration of 200 mg/L. , take 10 mg of the above ion-imprinted mesoporous material and place it in 10 mL of europium nitrate solution. After adsorption for 24 hours at room temperature, take a sample to measure the remaining Eu ³⁺ concentration in the solution. Finally, calculate its adsorption capacity according to formula (1):

In the formula: Q _e is the adsorption capacity of the sample, C ₀ is the initial concentration of rare earth ions, C _e is 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.

The ion-imprinted mesoporous material provided in this embodiment is used as an adsorbent to test the adsorption performance of different rare earth ions, which includes the following steps: take 10 mg of the above-mentioned ion-imprinted mesoporous material and place it in 10 mL of a rare earth solution containing competing ions, in which the rare earth ion Eu ³ The contents of ⁺ and competing ions Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Fe ³⁺ , and Al ³⁺ are all 100 ppm. After adsorption for 24 hours at room temperature, samples were taken to measure the concentration of Eu ³⁺ and competing ions remaining in the solution, and Calculate its adsorption capacity and selectivity with the help of formulas (1), (2) and (3):

In the formula: K _d is the distribution coefficient in ml·g ^-1 , q _e is the adsorption capacity of the sample, C _e is the remaining concentration of rare earth ions after adsorption, α is the selective separation factor, K _d1 and K _d2 are the adsorption targets respectively. _Kd of ions and adsorbed competing ions.

Example 9

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, and everything else is the same as Example 1.

Example 10

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, and everything else is the same as Example 1.

Example 11

The difference between this embodiment and Example 1 is that the iminodiacetic acid-modified silane coupling agent is replaced by a 4-vinylpyridine-modified silane coupling agent, and everything else is the same as in Example 1.

Example 12

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

Example 13

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

Comparative example 1

The difference between this comparative example and Example 1 is that the iminodiacetic acid-modified silane coupling agent was replaced with an equal amount of unmodified silane coupling agent, and everything else was the same as Example 1.

Comparative example 2

The difference between this comparative example and Example 1 is that the chitin nanocrystals are replaced by cellulose nanocrystals with equal content, and everything else is the same as Example 1.

Comparative example 3

The difference between this comparative example and Example 1 is that no Nd ³⁺ imprinted ion source is added, and everything else is the same as Example 1.

Test Conditions

The concentration of the remaining rare earth ion solutions after adsorption provided in Examples 1 to 13 and Comparative Examples 1 to 3 was tested. The test method is as follows:

Dilute 1 mL of the remaining rare earth ion solution after adsorption 5 times with deionized water, and similarly dilute 1 mL of the rare earth ion solution before adsorption 5 times, and test its ion concentration with ICP.

The test results are shown in Table 1:

Table 1

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

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

(2) It can be seen from the comparison of Examples 1-6, Examples 9-10 and Examples 12-13 that the present invention regulates the molar ratio of the silane coupling agent modified by a specific type of functional monomer to the silicon source to (0.6 -1.0): (9.0-9.4) optimal range, while adjusting the quality of the imprinted ion source to the optimal range of 30-50mg, the adsorption capacity is higher than 100mg·g ^-1 , exceeding the above optimal range, resulting in a reduction in the adsorption capacity of the material, Selectivity also becomes worse.

(3) From the comparison between Example 1 and Example 11, it can be seen that compared with other functional monomers, iminodiacetic acid is the most suitable functional monomer for adsorbing Nd ³⁺ .

(4) From the comparison of Example 1, Example 7 and Example 8, it can be seen that compared with other rare earth ions, iminodiacetic acid is the most suitable functional monomer for adsorbing Nd ³⁺ .

(5) Comparing Example 1 and Comparative Example 2, it can be seen that in chiral biomass as a hard template material, chitin nanocrystals can provide more imprinting sites because they contain certain amine groups, so the adsorption capacity Has obvious superiority.

(6) From the comparison between Example 1 and Comparative Example 3, it can be seen that the adsorption selectivity of the non-ionically imprinted mesoporous membrane prepared without adding Nd ³⁺ imprinted ion source is significantly reduced.

The applicant declares that the present invention illustrates the process method of the present invention through 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 replacement of raw materials selected 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 (10)

1. A method for preparing ion-imprinted mesoporous materials, characterized in that the method includes the following steps: (1) Hydrolyze the pretreated biomass waste to obtain chiral nanocrystals; (2) React 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 to obtain a precursor material; and then use the precursor material The material is sequentially subjected to evaporation drying and de-double template processing to obtain the ion-imprinted mesoporous material. 2. The method according to claim 1, characterized in that in step (1), the pretreatment includes a purification process; Preferably, the purification process is to first soak the biomass waste in a strong acid solution with a concentration of 1 mol/L for 10-15 hours, and then soak it in a strong alkali solution with a concentration of 1 mol/L for 10-15 hours, and repeat the above operations. ; Preferably, the biomass waste includes biomass waste containing lignocellulose and/or chitin; Preferably, the biomass waste includes any one or a combination of at least two of wood chips, waste paper, crab shells, shrimp shells or insects; Preferably, the strong acid solution includes hydrochloric acid solution and/or sulfuric acid solution; Preferably, the strong alkaline solution includes sodium hydroxide solution; Preferably, in step (1), when the biomass waste is biomass waste containing lignocellulose, the pretreatment process also includes bleaching treatment; Preferably, in step (1), when the biomass waste is biomass waste containing chitin, the pretreatment process also includes bleaching and deacetylation in sequence; Preferably, the bleaching process includes decolorizing and deodorizing in a solution containing a bleaching reagent; Preferably, the bleaching agent includes sodium hypochlorite and/or hydrogen peroxide; Preferably, the mass concentration of the bleaching reagent is 5wt%; Preferably, the decolorization and deodorization temperature is 70°C and the time is 2 hours. 3. The method according to claim 1 or 2, characterized in that the process of deacetylation includes using sodium hydroxide solution for high temperature treatment; Preferably, the mass concentration of the sodium hydroxide solution is 35wt%; Preferably, the temperature of the high-temperature treatment is 90°C and the time is 0.5-4h; Preferably, in step (1), the hydrolysis treatment process is to use hydrochloric acid solution for hydrolysis treatment; Preferably, the concentration of the hydrochloric acid solution is 3mol/L; Preferably, in step (1), the temperature of the hydrolysis treatment is 90-100°C and the time is 1.5 h. 4. The method according to any one of claims 1-3, characterized in that in step (2), the mass concentration of the solution containing the chiral nanocrystals in step (1) is 2-4wt %; Preferably, in step (2), the structure of the functional monomer contains amino and/or carboxyl groups, preferably a combination of amino and carboxyl groups; Preferably, in step (2), the functional monomer includes any one or at least two of ethylenediaminetetraacetic acid, 4-vinylpyridine, p-aminobenzoic acid or dimethylaminoethyl methacrylate. combination; 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 the solution of the functional monomer containing amino and/or carboxyl groups to alkaline, cooling Then slowly add siloxane in batches, adjust the pH to acidity after the reaction, and obtain the silane coupling agent modified by the functional monomer; Preferably, the process of adjusting the pH to alkaline is to use sodium hydroxide solution to adjust the pH value to 11; Preferably, the concentration of the sodium hydroxide solution is 10 mol/L; Preferably, the cooling temperature is 0°C and the cooling time is 10 minutes; Preferably, the number of times of slowly adding silicone in batches is two times; Preferably, the temperature at which silicone is slowly added in batches is 0°C; Preferably, the siloxane includes 3-glycidoxypropyltrimethoxysilane; Preferably, the reaction temperature is 65°C and the reaction time is 6 hours; Preferably, the process of adjusting the pH to acidity is to use a nitric acid solution to adjust the pH value to 2.4. 5. The method according to any one of claims 1-4, wherein in step (2), the silicon source includes tetraethyl orthosilicate; 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), preferably (0.6-1.0): (9.0-9.4); Preferably, in step (2), the imprinted ion source includes any one or at least two of La ³⁺ , Ce ³⁺ , Pr ³⁺ , Nd ³⁺ , Sm ³⁺ or Eu ³⁺ rare earth ions. combination; Preferably, in step (2), the mass of the imprinted ion source is 20-100 mg, preferably 30-50 mg. 6. The method according to any one of claims 1 to 5, characterized in that in step (2), the reaction temperature is 60°C and the reaction time is 4 hours. 7. The method according to any one of claims 1-6, characterized in that in step (2), the evaporation and drying process is to pour the precursor material into a culture medium with a coating on the surface. In a dish, evaporate at room temperature to obtain a composite film; Preferably, the coating includes any one or a combination of at least two of fluorine-containing coatings, silicon-containing coatings or paraffin-containing coatings. 8. The method according to any one of claims 1 to 7, characterized in that in step (2), the method of removing double templates includes sulfuric acid elution and/or high-temperature calcination; Preferably, the sulfuric acid elution process involves reacting the composite membrane in a sulfuric acid solution with a concentration of 6 mol/L at 80-90°C for 5-8 hours; Preferably, the high-temperature calcination temperature is 500-600°C, the time is 5-7h, and the heating rate is 5-10°C/min. 9. An ion-imprinted mesoporous material, characterized in that the ion-imprinted mesoporous material is prepared by the method for preparing an ion-imprinted mesoporous material according to any one of claims 1 to 8. 10. A rare earth ion adsorbing material, characterized in that the rare earth ion adsorbing material includes the ion-imprinted mesoporous material according to claim 9.