Imprinted porous polymer adsorption material and preparation method and application thereof

Abstract

The present invention relates to the technical field of adsorption materials, and provides an imprinted porous polymer adsorption material and its preparation method and application. The present invention uses rubidium ions as template ions, nano-TiO2 / Fe3O4 as a composite carrier, and through silanization surface modification, uses crown ether-calixarene as a joint functional monomer to coordinate with the template ion, and then uses a cross-linking agent and an initiator to carry out polymerization to prepare a porous polymer, and then elutes the template ion to obtain an imprinted porous polymer adsorption material. The imprinted porous polymer adsorption material provided by the present invention can efficiently and selectively adsorb rubidium ions, and has high adsorption capacity and good stability, and can achieve efficient separation and enrichment of rubidium in a complex system. At the same time, the adsorption material can be recovered under the action of an external magnetic field to achieve rapid separation between the adsorbent and the adsorbed solution.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption materials, and in particular to an imprinted porous polymer adsorption material and a preparation method and application thereof. Background Art

[0002] Rubidium, a rare and precious metal element, exhibits broad application prospects and significant commercial value in electronics, energy, aviation, chemical catalysis, and medicine. Rubidium is abundant in nature, but there are no minerals with rubidium as its primary component. Rubidium often occurs as an associated element in minerals such as lepidolite and cesium garnet, or in salt lake brines, coexisting with numerous metal ions such as potassium, sodium, magnesium, and calcium, as well as impurities such as organic matter. Due to the extremely high value of rubidium ions, extracting and separating them from minerals or salt lake brines containing multiple components and impurities is a pressing challenge.

[0003] At present, common methods for separating and enriching rubidium include precipitation, extraction, and adsorption. The precipitation method is costly, some of the process is relatively complicated, and the precipitate is not very stable. In the extraction method, the extractant is expensive and easy to lose, the amount of water that needs to be treated during the extraction process is large, the corrosion is large, and it is easy to cause pollution during the production process. Compared with other methods, the adsorption method has the advantages of simple process, high recovery rate, and environmental friendliness. The core principle of the adsorption method is to use an adsorbent to selectively adsorb rubidium ions. After the adsorption is saturated, the enrichment of rubidium and the regeneration of the adsorbent are achieved by elution. However, there is currently little research and development on rubidium adsorbents, and existing adsorbents have poor selectivity for rubidium, making it difficult to adapt to the efficient separation and enrichment of rubidium in complex systems. Summary of the Invention

[0004] In view of this, the present invention provides an imprinted porous polymer adsorbent material, its preparation method, and its application. The imprinted porous polymer adsorbent provided by the present invention has high selectivity for rubidium ions, and has the advantages of high capacity and high stability, enabling efficient separation and enrichment of rubidium in complex systems.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for preparing an imprinted porous polymer adsorption material comprises the following steps:

[0007] Mixing a divalent iron salt, a trivalent iron salt, a titanium source, ammonia water and water to perform a coprecipitation reaction to obtain a coprecipitation product; calcining the coprecipitation product to obtain a nano-TiO2 / Fe3O4 composite carrier;

[0008] The nano-TiO2 / Fe3O4 composite carrier, 3-aminopropyltriethoxysilane and a solvent are mixed to carry out a surface silanization reaction to obtain a silanized composite carrier;

[0009] The silanized composite carrier, 18-crown-6-acrylate, an activator and a solvent are mixed to carry out a condensation reaction to obtain a crown etherified composite carrier;

[0010] The crown ether composite carrier, sulfonated calix[4]arene and solvent are mixed and self-assembled to obtain a crown ether-arene-composite carrier;

[0011] Mixing the crown ether-aromatic hydrocarbon-composite carrier and the rubidium salt solution to perform template preassembly to obtain a preassembled complex;

[0012] mixing the preassembled complex, methacrylic acid, a crosslinking agent and an initiator to perform ion imprinting polymerization to obtain a polymer;

[0013] The Rb in the polymer + After elution, the imprinted porous polymer adsorption material was obtained.

[0014] Preferably, the molar ratio of the divalent iron salt to the ferric iron salt is 1:2-2.5; the titanium source is titanium tetrachloride; and the molar ratio of the total molar amount of the divalent iron salt and the ferric iron salt to the titanium source is 1:4-6;

[0015] The coprecipitation reaction temperature is 50-70°C, the time is 5-7 hours, and the pH value is 10-11;

[0016] Preferably, the calcination temperature is 400-600° C. and the calcination time is 1-3 hours.

[0017] Preferably, the usage ratio of the nano-TiO2 / Fe3O4 composite carrier and 3-aminopropyltriethoxysilane is 5g:1~3mL; the temperature of the surface silanization reaction is 70~90℃, and the time is 7~9h.

[0018] Preferably, the mass ratio of the nano-TiO2 / Fe3O4 composite carrier to 18-crown-6-acrylate is 5:0.1-0.2; the activator includes carbodiimide and N-hydroxysuccinimide; the temperature of the condensation reaction is 50-70°C, and the time is 10-15 hours.

[0019] Preferably, the molar ratio of the 18-crown-6-acrylate to the sulfonated calix[4]arene is 1:0.2-3, and the self-assembly time is 20-30 hours.

[0020] Preferably, the concentration of the rubidium salt solution is 0.1-0.3 mol / L; the pH value of the template pre-assembly is 7-8, and the time is 10-15 hours;

[0021] The usage ratio of the nano-TiO2 / Fe3O4 composite carrier and methacrylic acid is 1g:0.1~0.2mL;

[0022] The volume ratio of the methacrylic acid to the cross-linking agent is 1:3-5; the cross-linking agent is ethylene glycol dimethacrylate; and the initiator is an azo initiator;

[0023] The elution agent used in the elution is an acid solution; and the elution is carried out under ultrasonic oscillation conditions. The present invention also provides an imprinted porous polymer adsorption material prepared by the preparation method described in the above scheme.

[0024] The present invention also provides the use of the imprinted porous polymer adsorption material described in the above solution in the adsorption of rubidium ions.

[0025] The present invention also provides a method for separating and enriching rubidium in a solution after lithium extraction from lepidolite, comprising the following steps:

[0026] The lithium-extracted solution from lepidolite is mixed with the imprinted porous polymer adsorption material described in the above scheme to adsorb rubidium ions.

[0027] The present invention provides a preparation method of an imprinted porous polymer adsorption material, comprising the following steps: mixing a divalent iron salt, a trivalent iron salt, a titanium source, ammonia water and water for coprecipitation reaction to obtain a coprecipitation product; calcining the coprecipitation product to obtain a nano-TiO2 / Fe3O4 composite carrier; mixing the nano-TiO2 / Fe3O4 composite carrier, 3-aminopropyltriethoxysilane and a solvent for surface silanization reaction to obtain a silanized composite carrier; mixing the silanized composite carrier, 18-crown-6-acrylate, an activator and a solvent for condensation reaction to obtain a crown ether composite carrier; mixing the crown ether composite carrier, sulfonated calix[4]arene and a solvent for self-assembly to obtain a crown ether-arene-composite carrier; mixing the crown ether-arene-composite carrier and a rubidium salt solution for template pre-assembly to obtain a pre-assembled composite; mixing the pre-assembled composite, methacrylic acid, a cross-linking agent and an initiator for ion imprinting polymerization to obtain a polymer; and + The present invention uses nano-TiO2 / Fe3O4 as a composite carrier. On the one hand, the high specific surface area of ​​nano-TiO2 can provide a large number of active sites to enhance the adsorption capacity. At the same time, the magnetic properties of Fe3O4 are utilized to enable the adsorption material of the present invention to be recovered under the action of an external magnetic field, thereby achieving rapid separation between the adsorbent and the adsorbed solution. The present invention uses crown ether-calixarene as a combined functional monomer and template (Rb +) coordination, compared with a single functional monomer, the dual coordination of crown ether-calixarene can form cavity complementarity and multiple force synergy, thereby improving the selectivity of the adsorbent material for rubidium ions and greatly improving the adsorption capacity. In summary, the imprinted porous polymer adsorbent prepared by the present invention has high selectivity, high capacity and high stability, and can achieve efficient separation and enrichment of rubidium in complex systems; at the same time, the preparation method provided by the present invention has a simple process, low cost, strong operability, and is suitable for industrial production. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing an imprinted porous polymer adsorption material, comprising the following steps:

[0029] Mixing a divalent iron salt, a trivalent iron salt, a titanium source, ammonia water and water to perform a coprecipitation reaction to obtain a coprecipitation product; calcining the coprecipitation product to obtain a nano-TiO2 / Fe3O4 composite carrier;

[0030] The nano-TiO2 / Fe3O4 composite carrier, 3-aminopropyltriethoxysilane and a solvent are mixed to carry out a surface silanization reaction to obtain a silanized composite carrier;

[0031] The silanized composite carrier, 18-crown-6-acrylate, an activator and a solvent are mixed to carry out a condensation reaction to obtain a crown etherified composite carrier;

[0032] The crown ether composite carrier, sulfonated calix[4]arene and solvent are mixed and self-assembled to obtain a crown ether-arene-composite carrier;

[0033] Mixing the crown ether-aromatic hydrocarbon-composite carrier and the rubidium salt solution to perform template preassembly to obtain a preassembled complex;

[0034] mixing the preassembled complex, methacrylic acid, a crosslinking agent and an initiator to perform ion imprinting polymerization to obtain a polymer;

[0035] The Rb in the polymer + After elution, the imprinted porous polymer adsorption material was obtained.

[0036] The present invention comprises mixing a ferrous salt, a ferric salt, a titanium source, ammonia, and water to perform a coprecipitation reaction to obtain a coprecipitation product; the coprecipitation product is calcined to obtain a nano-TiO2 / Fe3O4 composite carrier. In the present invention, the ferrous salt is preferably ferric dichloride, and the ferric salt is preferably ferric chloride; the molar ratio of the ferrous salt to the ferric salt is preferably 1:2-2.5, more preferably 1:2; the titanium source is preferably titanium tetrachloride; the molar ratio of the total molar amount of the ferrous salt and the ferric salt to the titanium source is preferably 1:4-6, more preferably 1:5; the water is preferably deoxygenated water; the coprecipitation reaction temperature is preferably 50-70°C, more preferably 60°C, the reaction time is preferably 5-7 hours, more preferably 6 hours, and the pH value is preferably 10-11. In a specific embodiment of the present invention, it is preferred to first dissolve the divalent iron salt and the trivalent iron salt in water, then add a titanium source, then add ammonia water to adjust the pH value to 10~11, and then heat to the above temperature to carry out a co-precipitation reaction; the co-precipitation product is specifically a hydroxide precursor of the composite support; after the co-precipitation reaction is completed, the present invention preferably performs solid-liquid separation on the obtained product liquid, washes the obtained co-precipitation product, and then calcines it.

[0037] In the present invention, the calcination temperature is preferably 400~600℃, more preferably 500℃, and the calcination time is preferably 1~3h, more preferably 2h; during the calcination process, the hydroxide precursor forms a stable crystalline oxide to obtain a nano-TiO2 / Fe3O4 composite support; the nano-TiO2 / Fe3O4 composite support includes Fe3O4 and TiO2 nanoparticles coated on the surface of the Fe3O4.

[0038] After obtaining the nano-TiO2 / Fe3O4 composite support, the present invention mixes the nano-TiO2 / Fe3O4 composite support, 3-aminopropyltriethoxysilane (APTES) and a solvent to perform a surface silanization reaction to obtain a silanized composite support (denoted as NH2-TiO2 / Fe3O4). In the present invention, the amount ratio of the nano-TiO2 / Fe3O4 composite carrier and 3-aminopropyltriethoxysilane is preferably 5g:1~3mL; the solvent used for the surface silanization reaction is preferably toluene; the temperature of the surface silanization reaction is preferably 70~90°C, more preferably 80°C. In a specific embodiment of the present invention, the surface silanization reaction is preferably carried out under reflux conditions; the time of the surface silanization reaction is preferably 7~9h, more preferably 8h. The surface silanization reaction is preferably carried out under protective gas, and the protective gas is preferably nitrogen; after the surface silanization reaction is completed, the present invention preferably magnetically separates the obtained product liquid, washes the solid product and then dries it to obtain the silylated composite carrier, and the washing is preferably carried out using toluene, ethanol and deionized water in sequence, and the drying temperature is preferably 60°C.

[0039] After obtaining the silylated composite support, the present invention combines the silylated composite support with 18-crown-6-acrylate, an activator, and a solvent for a condensation reaction to obtain a crown-ether composite support (denoted as crown-TiO2 / Fe3O4). The present invention has no particular requirements for the source of the 18-crown-6-acrylate; it can be prepared using a commercially available product or methods well known to those skilled in the art. In a specific embodiment of the present invention, the 18-crown-6-acrylate can be prepared by the following method: 18-crown-6, acryloyl chloride, and DMF are mixed and subjected to an esterification reaction to obtain 18-crown-6-acrylate. The molar ratio of 18-crown-6 to acryloyl chloride is preferably 1:1.2. The esterification reaction temperature is preferably 60°C, and the reaction time is preferably 12 hours. The mass ratio of the TiO2 / Fe3O4 composite support and 18-crown-6-acrylate is preferably 5:0.1~0.2, specifically 5:0.19; the activator preferably includes dicarboxylic diimide (EDC) and N-hydroxysuccinimide (NHS); the amount ratio of 18-crown-6-acrylate, EDC and NHS is preferably 0.5mmol:0.05~0.15g:0.05~0.1g, specifically 0.5mmol:0.1g:0.06g; the solvent used in the condensation reaction is preferably dimethylformamide (DMF); the temperature of the condensation reaction is preferably 50~70℃, more preferably 60℃, and the time of the condensation reaction is preferably 10~15h, more preferably 12h; in the present invention, 18-crown-6-acrylate is modified on the surface of the composite support through a condensation reaction.

[0040] After obtaining the crown ether composite carrier, the present invention mixes the crown ether composite carrier, sulfonated calix[4]arene and a solvent for self-assembly to obtain a crown ether-arene-composite carrier (denoted as crown ether-arene-TiO2 / Fe3O4). In the present invention, the solvent used for the self-assembly is preferably an alcohol, specifically methanol; the molar ratio of the 18-crown-6-acrylate to the sulfonated calix[4]arene is preferably 1:0.2-3, specifically 1:1 or 1:2; the self-assembly time is preferably 20-30 hours, specifically 24 hours, and the self-assembly can be carried out at room temperature; during the self-assembly process, the amino groups in the crown ether composite carrier and the sulfonic acid groups in the sulfonated calix[4]arene undergo electrostatic self-assembly to obtain the crown ether-arene-composite carrier.

[0041] After obtaining the crown ether-aromatic hydrocarbon-composite carrier, the present invention mixes the crown ether-aromatic hydrocarbon-composite carrier and a rubidium salt solution to perform template preassembly to obtain a preassembled complex. In the present invention, the rubidium salt in the rubidium salt solution is preferably RbNO3; the concentration of the rubidium salt solution is preferably 0.1~0.3mol / L, more preferably 0.1mol / L; the solvent of the rubidium salt solution is preferably an acetonitrile-water mixed solvent, and the volume ratio of acetonitrile and water in the acetonitrile-water mixed solvent is preferably 3~5:1, more preferably 4:1; the amount ratio of the nano-TiO2 / Fe3O4 composite support and the rubidium salt solution is preferably 1g:5~15mL, more preferably 1g:10mL; the pH value of the template preassembly is preferably 7~8, and the time of the template preassembly is preferably 10~15h, specifically 12h; the template preassembly can be carried out at room temperature; in a specific embodiment of the present invention, the crown ether-aromatic hydrocarbon-composite support and the rubidium salt solution are preferably ultrasonically dispersed, and then the pH value of the system is adjusted to 7~8, and then the template preassembly is carried out under static conditions.

[0042] After obtaining the preassembled complex, the present invention mixes the preassembled complex, methacrylic acid (MAA), a crosslinking agent and an initiator to perform ion imprinting polymerization to obtain a polymer (denoted as Rb + -IIP@TiO2 / Fe3O4). In the present invention, the amount ratio of the nano-TiO2 / Fe3O4 composite carrier and methacrylic acid is preferably 1g:0.1~0.2mL; the cross-linking agent is preferably ethylene glycol dimethacrylate (EGDMA); the volume ratio of methacrylic acid to the cross-linking agent is preferably 1:3~5, more preferably 1:4; the initiator is preferably an azo initiator, specifically azobisisobutyronitrile (AIBN); the amount ratio of methacrylic acid to the initiator is preferably 0.1mL:0.01~0.02g; in a specific embodiment of the present invention, after the template is pre-assembled, methacrylic acid, the cross-linking agent, and the initiator are directly added to the feed solution without any treatment to carry out the polymerization reaction; the polymerization reaction temperature is preferably 50~70°C, more preferably 60°C, and the time is preferably 20~30h, more preferably 24h; the polymerization reaction is preferably carried out under a protective atmosphere, and the protective atmosphere is preferably nitrogen. After the polymerization reaction is completed, the product is preferably subjected to magnetic separation and then washed with acetonitrile three times, and then dried at 60° C. to obtain a polymer.

[0043] After obtaining the polymer, the present invention converts the Rb +Elution to obtain an imprinted porous polymer adsorption material. In the present invention, the eluent used for the elution is preferably an acid solution, specifically a nitric acid solution or a hydrochloric acid solution; the concentration of the acid solution is preferably 0.1~0.2mol / L, more preferably 0.1mol / L; the number of elutions is preferably 1~3 times, and the single elution time is preferably 1~2h; the elution is preferably carried out under ultrasonic oscillation conditions; the present invention performs elution under ultrasonic oscillation conditions, which can improve the elution efficiency of rubidium ions. After the elution is completed, the present invention preferably centrifuges the obtained product liquid and then washes it with water until it is neutral, and then vacuum-dries it to obtain an imprinted porous polymer adsorption material.

[0044] In the present invention, during the template preassembly process, the functional monomers (18-crown-6-acrylate and sulfonated calix[4]arene) are combined with the template ion (Rb + ) are assembled to form a complex, and then a porous polymer is formed through polymerization reaction. The template ions are then eluted to obtain an imprinted porous polymer adsorption material with rubidium ion imprinting.

[0045] The present invention also provides an imprinted porous polymer adsorption material prepared by the preparation method described in the above scheme.

[0046] The present invention also provides the use of the imprinted porous polymer adsorption material described in the above solution in the adsorption of rubidium ions. In the present invention, the adsorption capacity of the imprinted porous polymer adsorption material for rubidium ions is 1.8-2.2 mmol / g.

[0047] The present invention also provides a method for separating and enriching rubidium in a solution after lithium extraction from lepidolite, comprising the following steps:

[0048] The lithium-extracted solution from lepidolite is mixed with the imprinted porous polymer adsorption material described in the above scheme to adsorb rubidium ions.

[0049] In the present invention, the lithium-extracted solution from lepidolite is specifically the mother liquor remaining after lithium-extracted from lepidolite; in the present invention, the lithium-extracted solution from lepidolite includes rubidium ions and impurity ions, and the impurity ions can specifically be Li + 、Na + , K + and Cs + One or more of the following: the adsorption time is preferably 1h~8h; the adsorption can be carried out at room temperature; during the adsorption process, the cavities in the imprinted porous polymer adsorption material selectively capture Rb through size screening and chemical coordination + , repelling other ions, thereby achieving Rb + selective adsorption.

[0050] After the adsorption is completed, the present invention preferably desorbs the imprinted porous polymer adsorption material after adsorption, and the desorption preferably includes: using an eluent to remove Rb + Elution, recovery of cavity activity, the eluted imprinted porous polymer adsorption material is recycled; the eluent and specific elution conditions are the same as those for eluting Rb when preparing the imprinted porous polymer adsorption material + The ion steps are the same and will not be repeated here. The imprinted porous polymer adsorption material provided by the present invention can be repeatedly adsorbed and desorbed, and after 10 cycles, the adsorption capacity retention rate is greater than 90%.

[0051] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] In the following examples and comparative examples, the nano-TiO2 / Fe3O4 composite support was prepared by dissolving FeCl2 and FeCl3 in water at a molar ratio of 1:2, adding TiCl4 so that the total molar ratio of FeCl2 and FeCl3 to TiCl4 was 1:5. Ammonia was slowly added to adjust the pH to 10. The reaction was carried out at 60°C for 6 hours, followed by solid-liquid separation of the resulting product. The resulting coprecipitated product was washed and calcined at 500°C for 2 hours to obtain the nano-TiO2 / Fe3O4 composite support.

[0053] Example 1

[0054] 5 g of pre-synthesized nano-TiO2 / Fe3O4 composite carrier was dispersed in 100 mL of toluene, 2 mL of APTES was added, and the mixture was refluxed at 80 ° C for 8 h under nitrogen protection. Magnetic separation was performed, and the mixture was washed with toluene, ethanol, and deionized water in sequence, and dried in vacuum at 60 ° C to obtain NH2-TiO2 / Fe3O4. Then 0.5 mmol (0.19 g) of 18-crown-6-acrylate and NH2-TiO2 / Fe3O4 were dispersed in 50 mL of DMF, 0.1 g of EDC and 0.06 g of NHS were added, and the mixture was reacted at 60 ° C for 12 h. Magnetic separation was performed, and the mixture was washed with DMF three times to obtain crown ether-TiO2 / Fe3O4. 0.5 mmol (0.43 g) of sulfonated calix[4]arene and crown ether-TiO2 / Fe3O4 were dispersed in 50 mL of methanol and stirred at room temperature for 24 h. Magnetic separation and methanol washing were performed to obtain crown ether-arene-TiO2 / Fe3O4 (the molar ratio of functional monomer 18-crown-6-acrylate to sulfonated calix[4]arene was 1:1). Crown ether-arene-TiO2 / Fe3O4 was dispersed in 50 mL of acetonitrile / water (the volume ratio of acetonitrile and water was 4:1) solution containing 0.1M RbNO3, ultrasonicated for 30 minutes, adjusted to pH 8.0, and allowed to stand at 25°C for 12 hours. 0.5 mL of methyl acrylic acid (MAA), 2 mL of EGDMA (crosslinking agent), and 0.05 g of AIBN were added, nitrogen was passed through to deoxygenate, and polymerized in a water bath at 60°C for 24 hours. Magnetic separation was performed, washed with acetonitrile three times, and dried at 60°C to obtain Rb + -IIP@TiO2 / Fe3O4. + -IIP@TiO2 / Fe3O4 was immersed in 0.1M HNO3 and treated with oscillation ultrasound for 1 h, repeated 3 times, washed with deionized water until neutral, and vacuum dried to obtain a blank imprinted porous polymer adsorbent material.

[0055] Adsorption test: 5 g of blank imprinted porous polymer adsorption material was added to 500 mL of lithium-extracted lepidolite solution, stirred at 25 ° C for 6 h, and after magnetic separation, the Rb content of the supernatant was determined. + The adsorption capacity of rubidium ions is calculated based on the concentration of rubidium and other impurity concentrations. Among them, the adsorption capacity Q of the adsorbent material for rubidium ions at time t is t Calculated by the following equation:

[0056] Q t =(C0-C t )V / W

[0057] Where: the initial solubility of rubidium ions is C0 (mg / L), and the concentration of rubidium ions after adsorption is C t (mg / L); W is the mass of the imprinted porous polymer adsorption material (g); V is the volume of the solution after lithium extraction (L).

[0058] The ion concentrations of the lithium-extracted solution before and after adsorption are shown in Table 1.

[0059] Cyclic stability experiment: The imprinted porous polymer adsorbent material after adsorption was immersed in 0.1M HNO3 and treated with oscillation ultrasound for 1 h, repeated 3 times, the eluate was washed with deionized water until neutral, and vacuum dried. The adsorption test was repeated on the desorbed imprinted porous polymer adsorbent material under the same adsorption conditions as above. After testing, the adsorption capacity retention rate of the adsorbent material was 92% after 10 repeated adsorption-desorption cycles.

[0060] Comparative Example 1

[0061] 0.5 mmol (0.19 g) of 18-crown-6-acrylate was dispersed in 50 mL of DMF and reacted at 60 °C for 12 h to obtain a crown ether coordination monomer. The monomer was then dispersed in 50 mL of acetonitrile-water (4:1, volume ratio) containing 0.1 M RbNO3, sonicated for 30 min, adjusted to pH 8.0, and allowed to stand at 25 °C for 12 h. 0.5 mL of methacrylic acid (MAA), 2 mL of EGDMA (crosslinker), and 0.05 g of AIBN were added, nitrogen was passed through to deoxygenate, and the product was polymerized in a water bath at 60 °C for 24 h. It was washed with acetonitrile three times and dried at 60 °C to obtain Rb + The material was immersed in 0.1 M HNO3 and subjected to oscillation and ultrasonic treatment for 1 h, repeated 3 times, washed with deionized water until neutral, and vacuum dried to obtain a blank imprinted adsorption material.

[0062] Adsorption test: 5 g of blank imprinted adsorption material was added to 500 mL of lithium-extracted lepidolite solution, stirred at 25 ° C for 6 h, and after magnetic separation, the Rb content of the supernatant was determined. + The adsorption capacity of rubidium ions was calculated by using the concentration of lithium and other impurities. The calculation method was the same as in Example 1. The ion concentrations of the solution before and after adsorption after lithium extraction are shown in Table 1.

[0063] Cyclic stability experiment: An adsorption-desorption cycle experiment was carried out in the manner of Example 1. The results showed that after 10 repeated adsorption-desorption cycles, the adsorption capacity retention rate of the adsorption material was 80%.

[0064] Table 1 Ion concentrations before and after adsorption of the lithium-extracted solution in Example 1 and Comparative Example 1

[0065]

[0066] According to the data in Table 1, it can be seen that the adsorption material in Example 1 has a higher selectivity for rubidium and a larger adsorption capacity.

[0067] Example 2

[0068] 5 g of pre-synthesized nano-TiO2 / Fe3O4 composite support was dispersed in 100 mL of toluene, 2 mL of APTES was added, and the mixture was refluxed at 80 ° C for 8 h under nitrogen protection. Magnetic separation was performed, and the mixture was washed with toluene, ethanol, and deionized water in sequence, and dried in vacuum at 60 ° C to obtain NH2-TiO2 / Fe3O4. Then 0.5 mmol (0.19 g) of 18-crown-6-acrylate and NH2-TiO2 / Fe3O4 were dispersed in 50 mL of DMF, 0.1 g of EDC and 0.06 g of NHS were added, and the mixture was reacted at 60 ° C for 12 h. Magnetic separation was performed, and the mixture was washed with DMF three times to obtain crown ether-TiO2 / Fe3O4. 1 mmol (0.86 g) of sulfonated calix[4]arene and crown ether-TiO2 / Fe3O4 were dispersed in 50 mL of methanol and stirred at room temperature for 24 h. Magnetic separation and methanol washing were performed to obtain crown ether-arene-TiO2 / Fe3O4 (the molar ratio of functional monomer 18-crown-6-acrylate to sulfonated calix[4]arene was 1:2). Crown ether-arene-TiO2 / Fe3O4 was dispersed in 50 mL of acetonitrile-water (the volume ratio of acetonitrile and water was 4:1) solution containing 0.1M RbNO3, ultrasonicated for 30 min, adjusted to pH 8.0, and allowed to stand at 25°C for 12 h. 0.5 mL of methyl acrylic acid (MAA), 2 mL of EGDMA (crosslinking agent), and 0.05 g of AIBN were added, nitrogen was passed through to deoxygenate, and polymerized in a water bath at 60°C for 24 h. Magnetic separation was performed, washed with acetonitrile three times, and dried at 60°C to obtain Rb + -IIP@TiO2 / Fe3O4. + -IIP@TiO2 / Fe3O4 was immersed in 0.1M HNO3 and treated with oscillation ultrasound for 1 h, repeated 3 times, washed with deionized water to neutrality, and vacuum dried to obtain a blank imprinted porous polymer adsorption material.

[0069] Adsorption test: 5 g of blank imprinted porous polymer adsorption material was added to 500 mL of lithium-extracted lepidolite solution, stirred at 25 ° C for 6 h, and after magnetic separation, the Rb content of the supernatant was determined. + The adsorption capacity of rubidium ions was calculated by using the concentration of lithium and other impurities. The calculation method was the same as in Example 1. The ion concentrations of the solution before and after adsorption after lithium extraction are shown in Table 2.

[0070] Cyclic stability experiment: An adsorption-desorption cycle experiment was carried out in the same manner as in Example 1. The results showed that after 10 repeated adsorption-desorption cycles, the adsorption capacity retention rate of the adsorption material was 90%.

[0071] Comparative Example 2

[0072] 0.5 mmol (0.43 g) of sulfonated calix[4]arene was dispersed in 50 mL of methanol and stirred at room temperature for 24 h to obtain an aromatic coordination monomer. The monomer was then dispersed in 50 mL of acetonitrile-water (acetonitrile and water volume ratio is 4:1) solution containing 0.1 M RbNO3, ultrasonicated for 30 min, adjusted to pH 8.0, and allowed to stand at 25 ° C for 12 h. 0.5 mL of methacrylic acid (MAA), 2 mL of EGDMA (crosslinker), and 0.05 g of AIBN were added, nitrogen was passed through to deoxygenate, and polymerization was carried out in a water bath at 60 ° C for 24 h. It was washed with acetonitrile three times and dried at 60 ° C to obtain Rb + -IIP. The material was immersed in 0.1 M HNO3 and subjected to oscillation and ultrasonic treatment for 1 h, repeated 3 times, washed with deionized water until neutral, and vacuum dried to obtain a blank imprinted adsorption material.

[0073] Adsorption test: 5 g of blank imprinted adsorption material was added to 500 mL of lithium-extracted lepidolite solution, stirred at 25 ° C for 6 h, and after magnetic separation, the Rb content of the supernatant was determined. + The adsorption capacity of rubidium ions was calculated by using the concentration of lithium and other impurities. The calculation method was the same as in Example 1. The ion concentrations of the solution before and after adsorption after lithium extraction are shown in Table 2.

[0074] Cyclic stability experiment: An adsorption-desorption cycle experiment was carried out in the manner of Example 1. The results showed that after 10 repeated adsorption-desorption cycles, the adsorption capacity retention rate of the adsorption material was 84%.

[0075] Table 2 Ion concentrations before and after adsorption of the lithium-extracted solution in Example 2 and Comparative Example 2

[0076]

[0077] According to the data in Table 2, it can be seen that the adsorption material in Example 2 has a higher selectivity for rubidium and a larger adsorption capacity.

[0078] In summary, the present invention uses rubidium ions as template ions and nano-TiO2 / Fe3O4 as composite carriers, and through silanization surface modification, crown ether-calixarene is used as a combined functional monomer to coordinate with the template ion, and then a polymerization reaction is carried out by a cross-linking agent and an initiator. After that, the imprinted porous polymer adsorption material is obtained through template elution and post-treatment, which can efficiently and selectively absorb rubidium ions. The preparation method provided by the present invention is simple to operate, the obtained adsorption material has a large specific surface area and a stable structure, and through dual coordination synergy, the adsorption sites of the material are increased, and the adsorption performance and repeatability of the material are improved. At the same time, the adsorption material can be recovered under the action of an external magnetic field to achieve rapid separation between the adsorbent and the adsorbed solution.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an imprinted porous polymer adsorption material, characterized in that: The following steps are involved: Mixing a divalent iron salt, a trivalent iron salt, a titanium source, ammonia water and water to perform a coprecipitation reaction to obtain a coprecipitation product; calcining the coprecipitation product to obtain a nano-TiO2 / Fe3O4 composite carrier; The nano-TiO2 / Fe3O4 composite carrier, 3-aminopropyltriethoxysilane and a solvent are mixed to carry out a surface silanization reaction to obtain a silanized composite carrier; The silanized composite carrier, 18-crown-6-acrylate, an activator and a solvent are mixed to carry out a condensation reaction to obtain a crown etherified composite carrier; The crown ether composite carrier, sulfonated calix[4]arene and solvent are mixed and self-assembled to obtain a crown ether-arene-composite carrier; Mixing the crown ether-aromatic hydrocarbon-composite carrier and the rubidium salt solution to perform template preassembly to obtain a preassembled complex; mixing the preassembled complex, methacrylic acid, a crosslinking agent and an initiator to perform ion imprinting polymerization to obtain a polymer; The Rb in the polymer + After elution, the imprinted porous polymer adsorption material was obtained.

2. The preparation method according to claim 1, characterized in that The molar ratio of the divalent iron salt to the ferric iron salt is 1:2-2.5; the titanium source is titanium tetrachloride; the molar ratio of the total molar amount of the divalent iron salt and the ferric iron salt to the titanium source is 1:4-6; The coprecipitation reaction temperature is 50-70° C., the reaction time is 5-7 hours, and the pH value is 10-11.

3. The preparation method according to claim 1, characterized in that The calcination temperature is 400-600° C., and the calcination time is 1-3 hours.

4. The preparation method according to claim 1, characterized in that The dosage ratio of the nano-TiO2 / Fe3O4 composite carrier and 3-aminopropyltriethoxysilane is 5g:1-3mL; the temperature of the surface silanization reaction is 70-90°C, and the time is 7-9h.

5. The preparation method according to claim 1, characterized in that The mass ratio of the nano-TiO2 / Fe3O4 composite carrier to 18-crown-6-acrylate is 5:0.1-0.2; the activator includes carbodiimide and N-hydroxysuccinimide; the temperature of the condensation reaction is 50-70°C, and the time is 10-15 hours.

6. The preparation method according to claim 1, characterized in that The molar ratio of the 18-crown-6-acrylate to the sulfonated calix[4]arene is 1:0.2-3, and the self-assembly time is 20-30 hours.

7. The preparation method according to claim 1, characterized in that The concentration of the rubidium salt solution is 0.1-0.3 mol / L; the pH value of the template pre-assembly is 7-8, and the time is 10-15 hours; The usage ratio of the nano-TiO2 / Fe3O4 composite carrier and methacrylic acid is 1g:0.1~0.2mL; The volume ratio of the methacrylic acid to the cross-linking agent is 1:3-5; the cross-linking agent is ethylene glycol dimethacrylate; and the initiator is an azo initiator; The eluent used for the elution is an acid solution; the elution is carried out under ultrasonic oscillation conditions.

8. The imprinted porous polymer adsorption material prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the imprinted porous polymer adsorption material according to claim 8 in rubidium ion adsorption.

10. A method for separating and enriching rubidium in a solution after lithium extraction from lepidolite, characterized in that: The following steps are involved: The lithium-extracted solution from lepidolite and the imprinted porous polymer adsorption material according to claim 8 are mixed to adsorb rubidium ions.

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