Iron ion silicon-based adsorbent material, preparation method and application thereof

Abstract

The present application relates to a kind of iron ion silicon-based adsorption material and its preparation method and application.The iron ion silicon-based adsorption material is prepared as follows: S1, vinyl silane is coupled to the surface of silica sphere to obtain modified silica sphere;S2, modified silica sphere is copolymerized with acrylic monomer and crosslinking agent to obtain iron ion silicon-based adsorption material.The iron ion silicon-based adsorption material of the present application has high adsorption capacity and excellent adsorption selectivity for iron ions, significantly improves the adsorption capacity of iron ions and realizes the directional adsorption removal of iron impurities in rare earth solution, providing a simple, convenient and efficient method for removing trace iron ions in rare earth solution.

Description

Technical Field

[0001] This invention belongs to the field of adsorption material preparation technology and rare earth element separation and purification, and relates to an iron ion silicon-based adsorption material, its preparation method and application. Background Technology

[0002] Iron is ubiquitous in rare earth minerals and is one of the most common impurities. Its presence significantly impacts the performance, quality, and effectiveness of downstream high-end rare earth functional materials. For example, iron impurities strongly quench the luminescence of phosphors, reduce the optical performance of lanthanum oxide optical glass, decrease the dielectric constant of rare earth oxides, increase leakage current, and deteriorate dielectric properties. Therefore, reducing the iron impurity content in rare earths is crucial for improving the quality of high-precision rare earth products.

[0003] Commonly used iron removal methods in rare earth separation and purification processes include chemical precipitation, solvent extraction, and ion exchange. Chemical precipitation offers advantages such as low production cost and ease of operation, but it suffers from poor selectivity and difficulty in forming precipitates for low-concentration iron impurities, making it unsuitable for deep removal of trace amounts of iron. Solvent extraction boasts high production efficiency and good selectivity, but when used for deep iron impurity removal, it requires multi-stage cascade processes, resulting in complex equipment. Ion exchange offers excellent iron removal depth, but suffers from high main element loss, low yield, and long production cycle.

[0004] Adsorption is a method of separation that utilizes the different binding abilities of organic ligands to ions. In this method, target ions are adsorbed onto a solid-phase material during the contact between a functionalized adsorbent material and a solution containing a mixture of various ions. This method offers advantages such as high efficiency, environmental friendliness, high selectivity, and ease of desorption, and has become the most effective means of preparing high-purity rare earth elements in recent years.

[0005] CN101711975A discloses an iron-imprinted silica gel, which uses mercaptopropylsilane as a functional monomer and is prepared using molecular imprinting technology with iron ions as a template, enabling selective enrichment of ferric ions (Fe(III)). CN104130440A discloses a method for preparing an iron-imprinted polymer, in which iron ions are used as a template and acrylamide as a functional monomer, and an iron-imprinted polymer is synthesized using ion imprinting technology. This product exhibits high adsorption capacity and good adsorption selectivity for iron ions. CN104130440A also discloses a method for preparing an iron-imprinted polymer, in which iron ions are used as a template and acrylic monomers as functional monomers, and an iron-imprinted polymer is synthesized using ion imprinting technology. The resulting iron-imprinted polymer has a porous structure composed of small particles, exhibiting a high iron removal rate of over 90%. Summary of the Invention

[0006] The inventors studied the iron ion imprinted adsorbent materials reported in CN101711975A, CN104130440A, and CN110407976A, and found that although they have a certain selectivity for iron ions, they have low adsorption capacity, complex preparation process, and high cost. Therefore, it is necessary to develop new adsorbent materials.

[0007] This invention selects silicon spheres as the substrate for the adsorption material, modifies their surface with a silane coupling agent, and then grafts highly selective ligands onto their surface through chemical bonding. The selective effect of the ligands on iron ions is used to compensate for the poor selectivity of the adsorption material, thus preparing an iron ion silicon-based adsorption material. This significantly improves the iron ion adsorption capacity and achieves the directional adsorption and removal of iron impurities in rare earth solutions.

[0008] This invention modifies the surface of silicon spheres through grafting to obtain a silicon-based adsorbent material for iron ions. This adsorbent material has a high adsorption capacity and excellent adsorption selectivity for iron ions, providing a simple, convenient, and efficient method for removing trace amounts of iron ions from rare earth solutions.

[0009] This invention provides a method for preparing iron-ion silicon-based adsorbent materials, comprising:

[0010] S1, Surface modification of silicon spheres: Vinylsilane is coupled to the surface of silicon spheres to obtain modified silicon spheres;

[0011] S2, Copolymerization: Modified silica spheres are copolymerized with acrylic monomers and crosslinking agents to obtain iron ion silicon-based adsorbent materials.

[0012] Step S1

[0013] In step S1, vinylsilane is first hydrolyzed to silanol, and then condensed with hydroxyl groups on the surface of the silicon sphere and dehydrated, thereby coupling to the surface of the silicon sphere.

[0014] Vinylsilanes are silanes containing one vinyl group in their molecules, and can be represented by the structure shown in Formula I:

[0015]

[0016] Wherein, R1 is a C1-C4 alkoxy or a C1-C4 alkoxy substituted with a C1-C4 alkoxy, particularly a C1-C2 alkoxy or a C1-C2 alkoxy substituted with a C1-C2 alkoxy;

[0017] R2 and R3 are each independently selected from C1-C4 alkoxy, C1-C4 alkoxy-substituted C1-C4 alkoxy, and C1-C4 alkyl, particularly C1-C2 alkoxy, C1-C2 alkoxy-substituted C1-C2 alkoxy, and C1-C2 alkyl.

[0018] In some embodiments, the vinylsilane is selected from vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltri(2-methoxyethoxy)silane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane.

[0019] In step S1, the ratio of vinylsilane to silicon balls can be 1 to 2 mL vinylsilane / g silicon balls, but is not limited to this.

[0020] In step S1, the coupling reaction is carried out in a solvent, which can be any solvent that does not affect the coupling reaction, such as water, methanol, ethanol, acetone, toluene, dimethylformamide, dimethyl sulfoxide, or combinations thereof, such as a mixture of water with methanol or ethanol, but is not limited thereto.

[0021] In step S1, the temperature of the coupling reaction is not particularly limited and can range from room temperature to 90°C, preferably 50–90°C. There is no particular limitation on the reaction time; lower temperatures require longer reaction times, while higher temperatures are beneficial for accelerating the reaction rate. Generally, the reaction time can be more than 2 hours, for example, 6–48 hours.

[0022] In some embodiments, step S1 further includes performing solid-liquid separation after the coupling reaction is completed, washing and drying the solid to obtain modified silicon spheres.

[0023] The method of solid-liquid separation is not limited, such as centrifugation, atmospheric pressure filtration, and vacuum filtration (e.g., vacuum filtration), but is not limited to these.

[0024] Washing can be performed using any suitable method, as long as it removes the reaction byproducts. For example, washing can be performed using solvents and / or water.

[0025] There are no particular restrictions on the drying method; vacuum drying, etc., can be used.

[0026] In some cases, the surface of the silicon spheres used may contain adsorbed impurities that affect the coupling reaction.

[0027] Therefore, in some embodiments, step S1 further includes a step of activating the silicon spheres before the coupling reaction.

[0028] There are no particular restrictions on the method of activating silicon spheres, as long as it can activate the surface groups of the silicon spheres and facilitate the coupling reaction. For example, it can be done by acid leaching or high-temperature calcination.

[0029] In some embodiments, activation of the silicon spheres is carried out by acid immersion. For example, the silicon spheres are soaked in an acid solution, washed until neutral, and then dried. The acid solution can be hydrochloric acid, sulfuric acid, or nitric acid, and the molar concentration of the acid solution is preferably 1–6 mol / L. The preferred ratio of silicon spheres to acid is 5–20 mL of acid per gram of silicon spheres. The acid immersion time can be 24–72 h, and the preferred drying temperature is 40–80 °C, and the preferred drying time is 8–24 h. It is preferably carried out under reduced pressure, but the invention is not limited thereto.

[0030] There are no particular restrictions on the particle size of the silica spheres, as long as they can be used as an adsorbent material. For example, the particle size of the silica spheres can be 500-500 mesh, 100-200 mesh, etc.

[0031] Step S2

[0032] In step S2, using acrylic monomers as functional monomers, functional polymer materials are grafted onto the surface of modified silicon spheres by copolymerizing with vinyl silane, thereby preparing iron ion silicon-based adsorbent materials.

[0033] The acrylic monomers may be selected from acrylic acid, methacrylic acid, ethylacrylic acid, propylacrylic acid, phenylacrylic acid, benzylacrylic acid, etc., and are preferably acrylic acid.

[0034] The ratio of acrylic monomer to modified silica balls can be 1 to 27 mol acrylic monomer / g modified silica balls, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 mol acrylic monomer / g modified silica balls, preferably 9 to 27 mol acrylic monomer / g modified silica balls.

[0035] The crosslinking agent can be a monomer containing two vinyl groups in its molecule, such as diacrylate monomers, dimethacrylate monomers, divinylbenzene, and diacrylamide monomers, but is not limited thereto. In some embodiments, the crosslinking agent is selected from ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, pentaethylene glycol dimethacrylate, divinylbenzene, and N,N-methylenebisacrylamide, preferably ethylene glycol dimethacrylate.

[0036] Copolymerization can be initiated by an initiator. Any suitable initiator can be used without particular limitation. For example, the initiator can be a thermal initiator, such as an azo initiator, a peroxide initiator, or a persulfate initiator, such as azobisisobutyronitrile, ammonium persulfate, potassium persulfate, benzoyl peroxide, etc., with ammonium persulfate being preferred. When using a thermal initiator, the copolymerization temperature can be 50–100°C, and the time is preferably 1–48 hours. The specific temperature and time can be determined by conventional time based on the initiator used and its amount. Furthermore, copolymerization is usually carried out under a protective gas atmosphere to eliminate the negative impact of oxygen on the polymerization reaction. The protective gas can be nitrogen, helium, neon, or argon, with nitrogen being preferred.

[0037] Copolymerization can be carried out in a solvent. There are no particular limitations on the solvent, as long as it does not have a significant adverse effect on the polymerization. In some embodiments, the solvent may be water, methanol, ethanol, toluene, dimethyl sulfoxide, or combinations thereof, but is not limited thereto.

[0038] In some embodiments, step S2 further includes performing solid-liquid separation after the copolymerization reaction is completed, washing and drying the solid to obtain the iron ion adsorbent material.

[0039] The method of solid-liquid separation is not limited, such as centrifugation, atmospheric pressure filtration, and vacuum filtration (e.g., vacuum filtration), but is not limited to these.

[0040] Washing can be performed using any suitable method, as long as it removes the reaction byproducts. For example, washing can be performed using solvents and / or water.

[0041] There are no particular restrictions on the drying method; vacuum drying, etc., can be used.

[0042] The vacuum drying temperature is preferably 40–80°C, and the drying time is preferably 8–24 hours.

[0043] In another aspect, the present invention provides an iron-silicon-based adsorbent material prepared by the above method.

[0044] Experiments show that the iron ion silicon-based adsorbent material of the present invention can selectively adsorb iron ions from rare earth solutions and remove trace iron ion impurities from rare earth solutions.

[0045] Therefore, another aspect of the present invention provides the application of the iron ion silicon-based adsorbent material of the present invention for removing iron ions from rare earth solutions.

[0046] Another aspect of the present invention provides a method for removing iron ions from a rare earth solution, the method comprising the step of contacting the rare earth solution with the iron-ion silicon-based adsorbent of the present invention. By contacting the rare earth solution with the iron-ion silicon-based adsorbent of the present invention, the iron-ion silicon-based adsorbent of the present invention can selectively adsorb iron ions from the rare earth solution, thereby separating the iron ions from the rare earth element ions.

[0047] In this invention, the iron ion refers to the Fe(Ⅲ) ion.

[0048] The rare earth solution in this invention refers to a solution containing rare earth elements. The rare earth elements are trivalent and selected from one or more of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), promethium (Pm), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y), and scandium (Sc).

[0049] Beneficial effects:

[0050] 1) This invention uses acrylic acid as a functional monomer to graft iron ion silicon-based adsorbent material onto the surface of modified silicon spheres to achieve selective adsorption of iron ions, providing a simple new method for the selective separation of iron ions in rare earth solutions.

[0051] 2) The iron ion silicon-based adsorbent material of the present invention has the advantages of fast adsorption rate, good iron removal depth, high adsorption selectivity and simple preparation method. It can reach adsorption equilibrium within 45 minutes and reduce iron ion concentration from 60 mg / L to below 0.2 mg / L. It has excellent selectivity for iron ions in rare earth solutions and removes iron ions to below 0.3 mg / L while not adsorbing or adsorbing low rare earth ions. Attached image description:

[0052] Figure 1 The infrared spectra of the activated silicon spheres ASG and the obtained iron ion silicon-based adsorbent material in Example 2 of the present invention are shown.

[0053] Figure 2 This shows the effect of the iron ion silicon-based adsorbent material synthesized in Example 2 of the present invention on the iron adsorption capacity at different oscillation times.

[0054] Figure 3 This shows the effect of the iron ion silicon-based adsorbent material synthesized in Example 2 of the present invention on the iron ion adsorption capacity under different initial iron ion concentrations.

[0055] Figure 4 This shows the effect of the iron ion silicon-based adsorbent material synthesized in Example 2 of the present invention on the iron ion adsorption capacity at different solid-liquid ratios. Detailed implementation method:

[0056] To facilitate understanding of the present invention, the technical solutions of the present invention are further illustrated below with reference to embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as specific limitations thereof.

[0057] Example

[0058] Reagents and equipment

[0059] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0060] The microsphere silica gel was purchased from Macklin (catalog number: C875066), with a particle size of 100-200 mesh and a specific surface area of ​​400-500 m². 2 / g.

[0061] Vinyltrimethoxysilane, structural formula Purchased from Aladdin.

[0062] The acrylic monomer was purchased from Adamas.

[0063] Ethylene glycol dimethacrylate, structural formula Purchased from Macklin.

[0064] The contents of iron ions and rare earth elements in the solution were determined by inductively coupled plasma atomic emission spectrometry (ICP-OES) (instrument model: PQ9000, manufacturer: Jena).

[0065] Infrared spectra were measured on a Fourier transform infrared spectrometer (instrument model: IS-5, manufacturer: Thermo Fisher Scientific, USA).

[0066] Example 1

[0067] Take 50g of coarse-pore silica microspheres and soak them in 500mL of 3mol / L hydrochloric acid aqueous solution for 48h. Then wash them repeatedly with distilled water until neutral, filter them, and dry them under vacuum to obtain activated silica spheres ASG.

[0068] 10g of activated silicon spheres were placed in 100mL of 50% ethanol aqueous solution, and 10mL of vinyltrimethoxysilane (VTMS) was added. The mixture was stirred continuously at 50℃ for 24h. After the reaction was completed, the mixture was repeatedly washed with ethanol and distilled water, filtered, and dried under vacuum to obtain the product ASG-VTMS.

[0069] 18 mol of acrylic acid (AA) was placed in 100 mL of 50% ethanol aqueous solution, 2.5 g of ASG-VTMS was added, and the mixture was stirred for 2 h. Then, 1.5 mL of ethylene glycol dimethacrylate and 1 mmol of ammonium persulfate were added, and the mixture was stirred continuously at 60 °C under a nitrogen atmosphere for 24 h. After the reaction was completed, the mixture was repeatedly washed with ethanol and distilled water, filtered, and dried under vacuum to obtain the iron ion silicon-based adsorbent material.

[0070] The adsorption performance of the adsorbent material prepared in this embodiment was tested as follows: 10 mg of the prepared adsorbent material was weighed and added to 20 mL of 20 mg / L FeCl3 solution. The solution was shaken at 300 r / min for 90 min at 30 °C. The adsorbent material was filtered, and the filtrate was collected. The iron ion content in the filtrate was measured. The adsorption capacity of the iron ion adsorbent material was calculated by calculating the decrease in iron ions in the solution before and after adsorption. The adsorption capacity Q of the adsorbent material was calculated according to formula (1).

[0071]

[0072] Where Q represents the adsorption capacity (mg / g), c i With c e represents the initial and equilibrium concentrations of iron ions (mg / L), respectively; V represents the solution volume (L); and m represents the amount of adsorbent material used (g).

[0073] The test results show that the adsorption capacity of the adsorbent material prepared in this embodiment for Fe(III) is 23.41 mg / g, indicating that the obtained product has good adsorption performance for Fe(III).

[0074] Example 2

[0075] 27 mol of acrylic acid (AA) was placed in 100 mL of 50% ethanol aqueous solution, and 2.5 g of ASG-VTMS prepared in Example 1 was added. The mixture was stirred for 2 h, and then 2.65 mL of ethylene glycol dimethacrylate and 1 mmol of ammonium persulfate were added. The mixture was stirred continuously at 60 °C under a nitrogen atmosphere for 24 h. After the reaction was completed, the mixture was repeatedly washed with ethanol and distilled water, filtered, and dried under vacuum to obtain the iron ion silicon-based adsorbent material.

[0076] The infrared spectra of the activated silicon spheres ASG prepared in Example 1 and the iron ion silicon-based adsorbent material obtained in this example were measured, as follows: Figure 1 As shown.

[0077] Figure 1In the infrared spectra of both the activated silicon spheres ASG and the obtained iron-ion silicon-based adsorbent material, three Si-O-Si characteristic peaks appeared, and no significant change in peak position was observed before and after grafting, proving that grafting does not affect the chemical structure of the silicon sphere substrate. Furthermore, the infrared spectrum of the iron-ion silicon-based adsorbent material showed C=O and CH characteristic peaks, which were not present in the raw material ASG, indicating that acrylic acid successfully adhered to the silicon sphere surface.

[0078] Example 3

[0079] This embodiment examines the effect of different oscillation times on the adsorption capacity of iron ion silicon-based adsorbent materials.

[0080] Weigh 10 mg of the iron ion silicon-based adsorbent material synthesized in Example 2, add it to 20 ml of 20 mg / L FeCl3 solution, and place it at 30°C and shake at 300 r / min for different times. Filter the adsorbent material, collect the filtrate, determine the iron ion content in the filtrate, and calculate the adsorption capacity Q according to formula (1) in Example 1.

[0081] Test results are as follows Figure 2 As shown, this indicates that the adsorbent material has rapid adsorption kinetics. The adsorption capacity increases rapidly at first and then tends to level off, finally reaching adsorption equilibrium at 45 min, with an adsorption capacity as high as 24.34 mg / g.

[0082] Example 4

[0083] This embodiment investigates the effect of FeCl3 solutions of different concentrations on the adsorption capacity of iron ion silicon-based adsorbent materials.

[0084] Weigh 10 mg of the iron ion silicon-based adsorbent material synthesized in Example 2, add it to 20 ml of FeCl3 solution of different concentrations, and place it at 30°C and shake at 300 r / min for 45 min. Filter the adsorbent material, collect the filtrate, determine the iron ion content in the filtrate, and calculate the adsorption capacity Q according to formula (1) in Example 1.

[0085] Test results are as follows Figure 3 As shown, with the increase of the initial iron ion concentration, the adsorption capacity of the adsorbent material first increases rapidly and then tends to level off. When the iron ion concentration reaches 54 mg / L, the adsorption of the adsorbent material reaches saturation, and the maximum adsorption capacity can reach 43.71 mg / g.

[0086] Example 5

[0087] This embodiment examines the effect of different solid-liquid ratios on the adsorption capacity of iron ion silicon-based adsorbent materials.

[0088] Different masses of the iron-silicon-based adsorbent material synthesized in Example 2 were weighed according to solid-liquid ratios of 0.5, 1, 2, 3, 4, and 5 g / L, respectively. They were added to 20 ml of 60 mg / L FeCl3 solution and then placed at 30°C and shaken at 300 r / min for 45 min. The adsorbent material was filtered, the filtrate was collected, the iron ion content in the filtrate was determined, and the adsorption capacity Q was calculated according to formula (1) in Example 1.

[0089] Test results are as follows Figure 4 As shown, when the solid-liquid ratio is greater than 3 g / L, the iron ion removal rate reaches over 99%, with a maximum of 99.70%. The iron ion concentration can be reduced from 60 mg / L to below 0.2 mg / L, indicating that the obtained product has a good iron removal depth for Fe(III).

[0090] Example 6

[0091] This embodiment examines the selective adsorption performance of iron ion silicon-based adsorbents for iron ions in rare earth solutions.

[0092] A rare earth solution containing approximately 4 mg / L Fe(Ⅲ) (excluding Sc and Pm, with the remaining rare earth ions La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y each having a concentration of approximately 20 mg / L) is prepared as follows: Take 15 single solutions of rare earth chlorides of known concentration and ferric chloride solution in a volumetric flask according to the dosage calculated based on the given concentration, and then dilute to the mark with distilled water.

[0093] Weigh 10 mg of the iron ion silicon-based adsorbent material synthesized in Example 2, add 10 ml of rare earth solution, and place it at 30°C and shake at 300 r / min for 45 min. Filter the adsorbent material and collect the filtrate. Measure the iron ion and rare earth element ion content in the filtrate and calculate the removal rate. The results are shown in Table 1.

[0094] The removal rate R of metal ions is calculated according to formula (2).

[0095]

[0096] Among them, c i With c e These represent the initial and equilibrium concentrations (mg / L) of the metal ions, respectively.

[0097] Table 1 Removal rates of different ions by iron-silicon-based adsorbent materials

[0098] metal ions Initial concentration c i (mg / L) Equilibrium concentration c e (mg / L) Removal rate (%) Fe 4.234 0.2487 94.13 La 20.86 21.19 0 Ce 21.21 21.42 0 Pr 17.79 18.05 0 Nd 23.42 23.80 0 Sm 22.06 22.15 0 Eu 22.55 22.76 0 Gd 22.84 22.82 0 Tb 17.12 17.42 0 Dy 23.39 23.82 0 Ho 23.13 23.42 0 Er 19.17 19.22 0 Tm 22.06 22.73 0 Yb 22.67 22.67 0 Lu 22.26 22.81 0 Y 22.89 23.44 0

[0099] The iron-silicon-based adsorbent of this invention exhibits excellent adsorption selectivity for iron ions in rare earth solutions. After adsorption, the iron ion concentration drops to below 0.3 mg / L, while the concentration of rare earth ions remains unchanged. As shown in Table 1, the iron-silicon-based adsorbent of this invention can remove 94.13% of iron ions without adsorbing rare earth ions, thereby increasing the rare earth ion to iron ion concentration ratio in the solution from 76.4 to 1317.7, thus achieving the removal of trace iron ion impurities in rare earth solutions.

[0100] Comparative Example 1

[0101] 3 mmol Fe(NO3)3·9H2O and 18 mol acrylic acid (AA) were placed in 100 mL of 50% ethanol aqueous solution. 2.5 g of ASG-VTMS prepared in Example 1 was added and stirred for 2 h. Then 1.5 mL of ethylene glycol dimethacrylate and 1 mmol of ammonium persulfate were added. The mixture was stirred continuously at 60 °C under a nitrogen atmosphere for 24 h. After the reaction was completed, the sample was repeatedly washed with ethanol and distilled water, filtered, and vacuum dried. The dried sample was then repeatedly washed with HCl solution to remove template ions and vacuum dried to obtain the iron ion imprinted adsorbent material.

[0102] The adsorbent material prepared in this comparative example was subjected to the same adsorption performance test as in Example 1. The test results showed that the adsorbent material prepared in this comparative example had an adsorption capacity of 10.42 mg / g for iron ions, which was not as good as that of Example 1.

[0103] Comparative Example 2

[0104] 3 mmol Fe(NO3)3·9H2O and 27 mol acrylic acid (AA) were placed in 100 mL of 50% ethanol aqueous solution. 2.5 g of ASG-VTMS prepared in Example 1 was added and stirred for 2 h. Then 2.65 mL of ethylene glycol dimethacrylate and 1 mmol of ammonium persulfate were added. The mixture was stirred continuously at 60 °C under a nitrogen atmosphere for 24 h. After the reaction was completed, the sample was repeatedly washed with ethanol and distilled water, filtered, and vacuum dried. The dried sample was then repeatedly washed with HCl solution to remove template ions and vacuum dried to obtain the iron ion imprinted adsorbent material.

[0105] The adsorption material prepared in this comparative example was subjected to the same adsorption performance test as in Example 2. The test results showed that the adsorption capacity of the adsorption material prepared in this comparative example for Fe(III) was 19.56 mg / g, which was not as good as that of Example 2.

[0106] The adsorbent material prepared in this comparative example was subjected to the same selective adsorption performance test as in Example 6. The test results showed that the adsorbent material prepared in this comparative example had a removal rate of 0% for rare earth ions and a removal rate of 75.25% for iron ions. The iron ion concentration after adsorption was still greater than 1 mg / L, and the iron ion removal effect was not as good as that in Example 6.

[0107] While iron-imprinted adsorbents exhibit some selectivity for iron ions, their adsorption capacity is low, and their preparation process is complex, leading to high costs. The iron-silicon-based adsorbent of this invention adsorbs only iron and not rare earth ions in rare earth solutions, exhibiting a very high partition coefficient ratio between the target iron ion and competing ions. This excellent adsorption selectivity for iron is a significant advantage of the silicon-based adsorbent of this invention. Furthermore, the iron-silicon-based adsorbent of this invention has a high adsorption capacity for iron ions and a simple preparation process, reducing costs.

[0108] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An application of iron ion silicon-based adsorbent material for removing iron ions from rare earth solutions, characterized in that, The iron-ion silicon-based adsorbent material is prepared using a method comprising the following steps: S1, Surface modification of silicon spheres: Modified silicon spheres are obtained by coupling vinyl silane to the surface of silicon spheres; wherein... Vinylsilane is represented by the structure shown in Formula I: (I) Wherein, R1 is a C1-C4 alkoxy or a C1-C4 alkoxy substituted with a C1-C4 alkoxy; R2 and R3 are each independently selected from C1-C4 alkoxy, C1-C4 alkoxy-substituted C1-C4 alkoxy, and C1-C4 alkyl; S2, Copolymerization: Modified silica spheres are copolymerized with acrylic monomers and crosslinking agents to obtain an iron-ion silicon-based adsorbent material, wherein, The acrylic monomers are selected from acrylic acid, methacrylic acid, ethylacrylic acid, propylacrylic acid, phenylacrylic acid, and benzylacrylic acid; The crosslinking agent is selected from diacrylate monomers, dimethacrylate monomers, divinylbenzene, and diacrylamide monomers.

2. The application according to claim 1, characterized in that, R1 is a C1-C2 alkoxy or a C1-C2 alkoxy substituted with a C1-C2 alkoxy. R2 and R3 are each independently selected from C1-C2 alkoxy, C1-C2 alkoxy-substituted C1-C2 alkoxy, and C1-C2 alkyl.

3. The application according to claim 1, characterized in that, Vinylsilane is selected from vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltri(2-methoxyethoxy)silane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane.

4. The application according to claim 1, characterized in that, In step S1, The ratio of vinylsilane to silicon spheres is 1-2 mL vinylsilane / g silicon spheres; and / or The coupling reaction is carried out in a solvent; and / or The coupling reaction temperature is from room temperature to 90 °C; the reaction time is more than 2 hours.

5. The application according to claim 4, characterized in that, In step S1, The solvent is selected from water, methanol, ethanol, acetone, toluene, dimethylformamide, dimethyl sulfoxide, or combinations thereof; and / or The coupling reaction temperature is 50~90 ℃; the reaction time is 6~48 h.

6. The application according to claim 1, characterized in that, Step S1 also includes performing solid-liquid separation after the coupling reaction is completed, washing and drying the solid to obtain modified silicon spheres.

7. The application according to claim 1, characterized in that, Step S1 also includes activating the silicon spheres before the coupling reaction.

8. The application according to claim 7, characterized in that, Silicon spheres are activated by acid leaching.

9. The application according to claim 1, characterized in that, In step S2, The acrylic monomer is acrylic acid; and / or The ratio of the acrylic monomer to the modified silica spheres is 1~27 mol acrylic monomer / g modified silica spheres; and / or The crosslinking agent is selected from ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, pentaethylene glycol dimethacrylate, divinylbenzene, and N,N-methylenebisacrylamide; and / or Copolymerization is carried out in a solvent.

10. The application according to claim 9, characterized in that, The ratio of the acrylic monomer to the modified silica spheres is 9-27 mol acrylic monomer / g modified silica spheres; and / or The crosslinking agent is ethylene glycol dimethacrylate; and / or The solvent is selected from water, methanol, ethanol, toluene, dimethyl sulfoxide, or combinations thereof.

11. The application according to claim 1, characterized in that, Step S2 also includes performing solid-liquid separation after the copolymerization reaction is completed, washing and drying the solid to obtain the iron ion adsorbent material.

12. A method for removing iron ions from a rare earth solution, the method comprising the step of contacting the rare earth solution with the iron ion silicon-based adsorbent material as described in any one of claims 1-11.

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