Metal ion modified amino modified TiO2-SiO2 aerogel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of strontium-containing radioactive wastewater treatment, in particular to metal ion modified amino-modified TiO2-SiO2 aerogel as well as a preparation method and application thereof. The method comprises the following steps: mixing a metal chloride aqueous solution, TiO2-SiO2 hydrosol and a 1, 3-propane diamine aqueous solution, adjusting the pH value to 7-8, and carrying out gelation-aging treatment to obtain aged wet gel; the aged wet gel is soaked in water, solvent exchange is carried out, then freeze drying is carried out, the obtained metal ion modified amino modified TiO2-SiO2 aerogel has high adsorption efficiency, large adsorption capacity and good environmental adaptability, the problems of poor selectivity and poor anti-interference ability in the prior art are solved, and the metal ion modified amino modified TiO2-SiO2 aerogel has good application prospects. The defects that in the prior art, high-efficiency adsorption of 80% or above is difficult to achieve, the saturation adsorption capacity is mostly lower than 50 mg / g, and the treatment requirement of the high-concentration strontium-containing waste liquid cannot be met are overcome.

Description

Technical Field

[0001] This invention relates to the field of strontium-containing radioactive wastewater treatment technology, specifically to a metal ion-modified amino-modified TiO2-SiO2 aerogel, its preparation method, and its application. Background Technology

[0002] Nuclear energy, as a clean energy source, occupies an important position in the global energy structure. However, the development of the nuclear industry, including fuel reprocessing, nuclear power plant operation, and nuclear facility decommissioning, generates a large amount of radioactive waste. Among these, strontium-90 (90Sr) is one of the most hazardous fission products. With a half-life of 28.9 years, 90Sr is a pure beta radionuclide with chemical properties similar to calcium ions. It easily enters the human body through the food chain and accumulates in the skeletal system. Through high-energy beta rays, it causes severe damage to bone marrow and bone tissue, inducing diseases such as leukemia and bone cancer, posing a serious threat to human health. Furthermore, strontium-containing radioactive waste often exhibits high salinity, with NaCl content reaching as high as 400 g / L to 500 g / L, posing a significant challenge to its treatment and disposal, and has become an internationally recognized "difficult-to-treat" waste.

[0003] Currently, containing Sr 2+ Wastewater treatment methods mainly include solvent extraction and ion exchange. Solvent extraction often uses crown ether compounds as extractants. Although it offers selectivity, crown ethers are expensive and pose environmental safety risks as organic compounds, limiting their large-scale application. Zeolite for Sr... 2+ It has adsorption capacity, but its adsorption performance is significantly affected by pH. Under acidic conditions, K d The value can drop drastically from hundreds of mL / g to tens of mL / g, making it difficult to adapt to complex waste liquid environments; although ion exchange resins are easy to operate, they are mostly organic materials with poor radiation stability and are difficult to cure, which can easily cause secondary pollution.

[0004] Aerogels, as lightweight materials with ultra-high specific surface area and hierarchical porous structure, are hailed as "solid smog" and have shown great potential in the field of radionuclide capture. TiO2-SiO2 composite aerogels combine the high specific surface area of ​​silica with the chemical stability of titanium dioxide, and their adsorption performance can be further enhanced through surface functionalization modification. However, TiO2-SiO2 aerogels prepared by existing technologies have few surface active sites, which limits their ability to capture Sr. 2+ The adsorption capacity is low; the selectivity and anti-interference ability of TiO2-SiO2 composite aerogel modified with a single amino group need to be improved. Although some modified materials can improve the adsorption performance, it is difficult to achieve high-efficiency adsorption of more than 80% under pH>4 conditions, and the saturated adsorption capacity is mostly less than 50mg / g, which cannot meet the treatment needs of high-concentration strontium-containing waste liquid. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a metal ion-modified amino-modified TiO2-SiO2 aerogel, its preparation method, and its applications. This invention uses TiO2-SiO2 hydrosol as a substrate and metal chloride and 1,3-propanediamine as modifiers. Through a gelation-aging treatment combined with freeze-drying, metal ion doping and amino modification are synergistically introduced into the TiO2-SiO2 hydrosol framework. The invention utilizes the regulation of surface charge characteristics by metal ions and the effect of amino groups on Sr... 2+ The specific coordination of amino groups creates bifunctional adsorption sites, enabling the prepared metal ion-modified amino-modified TiO2-SiO2 aerogel to possess high adsorption efficiency, large adsorption capacity, and good environmental adaptability. This not only solves the problems of poor selectivity and anti-interference ability in existing technologies, but also overcomes the difficulty of achieving high-efficiency adsorption of over 80% under pH>4 conditions, and the fact that the saturation adsorption capacity is mostly below 50 mg / g, which cannot meet the treatment requirements of high-concentration strontium-containing wastewater. Among them, amino modification can introduce basic groups to enhance the complexation ability of TiO2-SiO2 aerogel for metal ions, while metal ion doping can optimize the electronic structure and surface active site distribution of TiO2-SiO2 aerogel.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a method for preparing metal ion-modified amino-modified TiO2-SiO2 aerogel, comprising the following steps: S1. Using TiO2-SiO2 hydrosol as a substrate and metal chloride and 1,3-propanediamine as modifiers, the aqueous solutions of metal chloride, TiO2-SiO2 hydrosol, and 1,3-propanediamine were mixed. After adjusting the pH to 7-8, the mixture underwent gelation-aging treatment to obtain an aged wet gel. The purpose of the gelation-aging treatment is to make the skeleton of the aged wet gel more rigid.

[0007] S2. The aged wet gel was immersed in water and solvent exchanged, and then freeze-dried to obtain metal ion modified amino-modified TiO2-SiO2 aerogel.

[0008] Preferably, the volume ratio of the aqueous solution of metal chloride, the aqueous solution of TiO2-SiO2, and the aqueous solution of 1,3-propanediamine is 1:1 to 2:1; wherein, in the aqueous solution of 1,3-propanediamine, the mass fraction of 1,3-propanediamine is 0.5% to 1.5%; and in the aqueous solution of metal chloride, the concentration of metal ions is 0.2 mol / L.

[0009] Preferably, the metal ions in the aqueous solution of the metal chloride are selected from Cu. 2+ Al 3+ Zn 2+ or Fe 2+ .

[0010] Preferably, ammonia water is used to adjust the pH, and the concentration of ammonia water is 0.5 mol / L to 2 mol / L.

[0011] Preferably, the gelation-aging process is as follows: first, let it stand at room temperature for 2 to 4 hours until it is completely gelled, and then continue to stand for at least 24 hours until it ages.

[0012] Preferably, the volume ratio of water to aged wet gel is 2~5:1. The volume of water should be larger than the volume of the aged wet gel, and the water needs to be replaced during solvent exchange.

[0013] Preferably, the freeze-drying conditions are: vacuum drying at -50℃ to -40℃ for at least 24 hours.

[0014] Preferably, the TiO2-SiO2 hydrosol is prepared according to the following steps: Tetrabutyl orthosilicate and tetrabutyl titanate were dissolved together in ethanol and then mixed with water to obtain TiO2-SiO2 hydrosol; wherein the molar ratio of tetrabutyl orthosilicate to tetrabutyl titanate was 1~2:1, and the mass-volume ratio of tetrabutyl orthosilicate to water was 2.5g:2mL~3mL.

[0015] The second objective of this invention is to provide a metal ion-modified amino-modified TiO2-SiO2 aerogel prepared by the above-described method.

[0016] A third objective of this invention is to provide the application of the above-mentioned metal ion-modified amino-modified TiO2-SiO2 aerogel in the preparation of radioactive strontium ion adsorbents.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing metal ion-modified amino-modified TiO2-SiO2 aerogel. Using TiO2-SiO2 hydrosol as a substrate and metal chloride and 1,3-propanediamine as modifiers, the method involves mixing an aqueous solution of metal chloride, an aqueous solution of TiO2-SiO2 hydrosol, and an aqueous solution of 1,3-propanediamine. After adjusting the pH to 7-8, the mixture undergoes a gelation-aging treatment to obtain an aged wet gel. The aged wet gel is then immersed in water and subjected to solvent exchange, followed by freeze-drying to obtain the metal ion-modified amino-modified TiO2-SiO2 aerogel. The metal ions react with Ti... 4+ Isomorphic or heteromorphic substitution occurs, partially occupying the Ti positions in TiO2. This is due to the interaction between metal ions and Ti. 4+ Differences in ionic radius, charge number, and coordination preference can lead to substitution behavior that disrupts the periodic arrangement of the original crystal lattice, resulting in local lattice distortion or the creation of defect structures with oxygen vacancies. For example, Cu... 2 + Zn2+ The introduction of transition metal ions can modulate the surface charge properties of TiO2-SiO2 aerogel and promote the interaction with Sr. 2+ Electrostatic interactions and ion exchange reactions.

[0018] The amino groups of this invention are firmly grafted onto the aerogel surface via covalent bonds (Si-N or Ti-N), avoiding the drawback of functional group loss in traditional physical impregnation methods. This composite structure of "inorganic framework-organic functional layer" enables metal ion-modified amino-modified TiO2-SiO2 aerogels to maintain structural integrity and adsorption activity under wide pH range (pH>4) and high salinity (NaCl 400g / L~500g / L) conditions. This overcomes the limitations of existing technologies, which struggle to achieve over 80% high-efficiency adsorption and have saturated adsorption capacities mostly below 50mg / g, failing to meet the treatment requirements of high-concentration strontium-containing wastewater. Furthermore, the defect sites induced by metal ion doping often exhibit high stability, maintaining structural integrity and functional activity even in complex aquatic environments. This overcomes the selectivity and anti-interference capabilities of existing technologies, providing a better foundation for the treatment of Sr. 2+ The selective recognition and efficient removal of [the substance] provide a reliable physicochemical basis.

[0019] 2. The metal ion-modified amino-modified TiO2-SiO2 aerogel of the present invention exhibits excellent structural stability and resistance to salt interference. This is attributed to: firstly, the TiO2-SiO2 aerogel forms a three-dimensional network structure through Si-O-Ti bonds, endowing the metal ion-modified amino-modified TiO2-SiO2 aerogel with high thermal stability and chemical inertness; secondly, the introduction of metal ions modulates the Zeta potential on the surface of TiO2-SiO2 aerogel, enhancing its resistance to Sr. 2+ The electrostatic attraction of Sr; while the amino group specifically recognizes Sr through coordination. 2+ The electrostatic-coordination bifunctional adsorption sites constructed by the two synergistically effectively reduce Na... + K + Interference from monovalent competing ions; thirdly, the introduction of metal ions can replace some of the Ti in TiO2, forming defect structures on the surface of metal ion-modified amino-modified TiO2-SiO2 aerogel. These defects not only increase the density of active sites on the surface of metal ion-modified amino-modified TiO2-SiO2 aerogel, but also change the surface electronic state distribution, making the defect region more susceptible to interference from Sr. 2+ It has a stronger electrostatic attraction or coordination binding ability.

[0020] Furthermore, the defect sites induced by metal ion doping often exhibit high stability, maintaining structural integrity and functional activity even in complex aquatic environments, thus providing a basis for Sr... 2+This provides a reliable physicochemical basis for the selective recognition and efficient removal of Sr. The defect modulation strategy further enhances the ability of metal ion-modified amino-modified TiO2-SiO2 aerogel to effectively remove Sr under competitive ion coexistence conditions. 2+ The specific adsorption capacity of the metal ion-modified amino-modified TiO2-SiO2 aerogel, together with its amino coordination and electrostatic attraction mechanism, forms multiple synergistic effects, which jointly enhance the application potential of metal ion-modified amino-modified TiO2-SiO2 aerogel in the actual treatment of strontium-containing wastewater. Attached Figure Description

[0021] Figure 1 The images show the XRD patterns of the Zn-amino-TiO2-SiO2 aerogel of Example 3, the TiO2-SiO2 aerogel of Comparative Example 1, and the Zn-TiO2-SiO2 aerogel of Comparative Example 4.

[0022] Figure 2 XPS images of Zn-amino-TiO2-SiO2 aerogel of Example 3, TiO2-SiO2 aerogel of Comparative Example 1, and Zn-TiO2-SiO2 aerogel of Comparative Example 4.

[0023] Figure 3 The TG curves are for Zn-amino-TiO2-SiO2 aerogel of Example 3, TiO2-SiO2 aerogel of Comparative Example 1, and Zn-TiO2-SiO2 aerogel of Comparative Example 4.

[0024] Figure 4 The nitrogen adsorption-desorption curves and pore size distribution diagrams of Zn-amino-TiO2-SiO2 aerogel of Example 3, TiO2-SiO2 aerogel of Comparative Example 1, and Zn-TiO2-SiO2 aerogel of Comparative Example 4 are shown, where a is the nitrogen adsorption-desorption curve and b is the pore size distribution diagram.

[0025] Figure 5 SEM images of Zn-amino-TiO2-SiO2 aerogel of Example 3, TiO2-SiO2 aerogel of Comparative Example 1, and Zn-TiO2-SiO2 aerogel of Comparative Example 4 are shown, where a is Comparative Example 1, b is Comparative Example 4, and c is Example 3.

[0026] Figure 6 The graph shows the effect of pH value on the adsorption performance of Zn-amino-TiO2-SiO2 aerogel of Example 3, TiO2-SiO2 aerogel of Comparative Example 1, and Zn-TiO2-SiO2 aerogel of Comparative Example 4 at different Sr concentrations. In the graph, a represents an Sr concentration of 10 mg / L and b represents an Sr concentration of 100 mg / L.

[0027] Figure 7The graph shows the effect of contact time on the adsorption performance of Zn-amino-TiO2-SiO2 aerogel in Example 3, TiO2-SiO2 aerogel in Comparative Example 1, and Zn-TiO2-SiO2 aerogel in Comparative Example 4. In the graph, a represents the effect of time on adsorption efficiency, and b represents the kinetic fit.

[0028] Figure 8 The graph shows the effect of initial concentration on the adsorption performance of Zn-amino-TiO2-SiO2 aerogel in Example 3, TiO2-SiO2 aerogel in Comparative Example 1, and Zn-TiO2-SiO2 aerogel in Comparative Example 4. In the graph, a represents the effect of initial strontium concentration on adsorption capacity, and b represents the fitting of adsorption isotherms.

[0029] Figure 9 The graph shows the effect of coexisting ions on the adsorption performance of Zn-amino-TiO2-SiO2 aerogel in Example 3, TiO2-SiO2 aerogel in Comparative Example 1, and Zn-TiO2-SiO2 aerogel in Comparative Example 4.

[0030] Figure 10 The graph shows the effect of different water concentrations on the adsorption performance of Zn-amino-TiO2-SiO2 aerogel in Example 3, TiO2-SiO2 aerogel in Comparative Example 1, and Zn-TiO2-SiO2 aerogel in Comparative Example 4. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods.

[0033] ① Addressing the problem of limited adsorption capacity in traditional adsorption materials: Existing TiO2-SiO2 aerogels or single-amino modified adsorption materials suffer from insufficient number of surface active sites and the interaction between active groups and Sr. 2+ The effect intensity is limited, on Sr 2+ The saturated adsorption capacity is mostly at a low level, making it difficult to treat high concentrations of Sr. 2+ Wastewater requires frequent replacement or addition of adsorbent materials in practical applications, increasing treatment costs and operational complexity.

[0034] The metal ion-modified amino-modified TiO2-SiO2 aerogel of this invention achieves a saturated adsorption capacity of 80 mg / g and a low-mass concentration adsorption efficiency of 95% through a synergistic modification strategy of "metal ion-amino". This significantly improves the adsorption capacity of the metal ion-modified amino-modified TiO2-SiO2 aerogel for high-mass concentrations of Sr. 2+ Its load-bearing capacity effectively overcomes the aforementioned defects.

[0035] ② Regarding the issue of limited material modification processes: Existing technologies mostly employ single metal ion doping or single amino group modification, resulting in materials with limited sr... 2+ Its selective adsorption capacity and anti-interference ability are relatively weak, especially in actual wastewater containing other metal ions (such as Na+). + K + Ca 2+ Adsorption performance is easily degraded under competition from other substances (such as α, β, γ).

[0036] This invention utilizes metal ions (Cu) 2+ Al 3+ Zn 2+ Fe 2+ The synergistic design of doping and amino (1,3-propanediamine) modification allows metal ions to modulate the surface charge properties of the material to enhance electrostatic interactions, while amino groups provide specific coordination sites. Together, they construct bifunctional adsorption sites, significantly improving the material's adhesion to Sr. 2+ Its selective recognition capability and anti-interference performance.

[0037] ③ Regarding the imperfections in aerogel preparation and post-processing: In some existing aerogel preparation processes, insufficient sol hydrolysis, inadequate gel aging time, and incomplete solvent exchange result in underdeveloped aerogel pore structures and low specific surface areas. Furthermore, the drying process easily causes pore collapse, further reducing the material's adsorption performance and failing to fully utilize the structural advantages of aerogels—high specific surface area and high porosity—thus limiting their adsorption capacity for Sr. 2+ The adsorption efficiency and capacity.

[0038] This invention utilizes metal ions (Cu) 2+ Al 3+ Zn 2+ Fe 2+ The synergistic modification process of doping and amino (1,3-propanediamine) was used to optimize the preparation and post-treatment parameters of TiO2-SiO2 aerogel, and finally an adsorption material with an adsorption efficiency of 95% and an adsorption capacity of 80 mg / g for strontium ions under pH>4 conditions was obtained, which also has good structural stability and anti-interference ability, in order to meet the actual needs of efficient and stable treatment of strontium ion-containing wastewater.

[0039] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: Example 1 A method for preparing a metal ion-modified amino-modified TiO2-SiO2 aerogel includes the following steps: S1. Add 0.012 mol tetraethyl orthosilicate and 0.008 mol tetrabutyl titanate to 20 mL of ethanol, stir at room temperature for 15 min, then add 2 mL of deionized water and continue stirring for 30 min to obtain TiO2-SiO2 hydrosol.

[0040] S2. Dissolve 10 mL of 0.2 mol / L CuCl2 in 10 mL of deionized water and stir until completely dissolved to obtain a metal ion solution; dissolve 0.1 g of 1,3-propanediamine (mass fraction 1%) in 10 mL of deionized water and stir at room temperature for 5 min to obtain an aqueous solution of 1,3-propanediamine.

[0041] S3. Mix 1 part (20 mL) of TiO2-SiO2 hydrosol and 10 mL of metal ion solution, and stir at 500 r / min at room temperature for 30 min to ensure uniform dispersion and obtain a mixed solution. Add 10 mL of 1,3-propanediamine aqueous solution to the mixed solution, continue stirring for 5 min, and then adjust the pH to 7 with 1 mol / L ammonia water at a dropping rate of 0.5 mL / min. Let stand at room temperature for 2 h until complete gelation, when the solution does not flow and no liquid drips when the bottle is inverted. After gelation, continue to stand for 24 h to obtain aged wet gel.

[0042] S4. The aged wet gel was immersed in deionized water and solvent exchanged at room temperature for 24 hours, during which the deionized water was replaced once to remove impurities such as residual ethanol and ammonia, resulting in a solvent-exchanged gel. The volume ratio of deionized water to the aged wet gel was 5:1. Subsequently, the solvent-exchanged gel was placed in a freeze dryer and dried under vacuum at -50°C for 24 hours to obtain a metal ion-modified amino-modified TiO2-SiO2 aerogel, denoted as Cu-amino-TiO2-SiO2 aerogel.

[0043] Example 2 A method for preparing a metal ion-modified amino-modified TiO2-SiO2 aerogel is the same as the preparation method in Example 1, except that CuCl2 in S2 is replaced with AlCl3 to obtain a metal ion-modified amino-modified TiO2-SiO2 aerogel, denoted as Al-amino-TiO2-SiO2 aerogel.

[0044] Example 3 A method for preparing a metal ion-modified amino-modified TiO2-SiO2 aerogel is the same as the preparation method in Example 1, except that CuCl2 in S2 is replaced with ZnCl2 to obtain a metal ion-modified amino-modified TiO2-SiO2 aerogel, denoted as Zn-amino-TiO2-SiO2 aerogel.

[0045] Example 4 A method for preparing a metal ion-modified amino-modified TiO2-SiO2 aerogel is the same as the preparation method in Example 1, except that CuCl2 in S2 is replaced with FeCl2 to obtain a metal ion-modified amino-modified TiO2-SiO2 aerogel, denoted as Fe-amino-TiO2-SiO2 aerogel.

[0046] Comparative Example 1 A method for preparing TiO2-SiO2 aerogel includes the following steps: S1. Add 0.012 mol tetraethyl orthosilicate and 0.008 mol tetrabutyl titanate to 20 mL of ethanol, stir at room temperature for 15 min, then add 2 mL of deionized water and continue stirring for 30 min to obtain TiO2-SiO2 hydrosol.

[0047] S2. Adjust the pH of the TiO2-SiO2 hydrosol to 7 using 1mol / L ammonia water at a dropping rate of 0.5mL / min. Let it stand at room temperature for 2h until it is completely gelled. The solution does not flow and no liquid slips when the bottle is inverted. After gelation, continue to let it stand for 24h to obtain aged wet gel.

[0048] S3. The aged wet gel was immersed in deionized water and solvent exchanged at room temperature for 24 hours, during which the deionized water was replaced once to remove impurities such as residual ethanol and ammonia, to obtain a solvent-exchanged gel; wherein the volume ratio of deionized water to aged wet gel was 5:1. Subsequently, the solvent-exchanged gel was placed in a freeze dryer and dried under vacuum conditions at -50℃ for 24 hours to obtain TiO2-SiO2 aerogel.

[0049] Comparative Example 2 A method for preparing metal ion-modified TiO2-SiO2 aerogel includes the following steps: S1. Add 0.012 mol tetraethyl orthosilicate and 0.008 mol tetrabutyl titanate to 20 mL of ethanol, stir at room temperature for 15 min, then add 2 mL of deionized water and continue stirring for 30 min to obtain TiO2-SiO2 hydrosol.

[0050] S2. Dissolve 10 mL of 0.2 mol / L CuCl2 in 10 mL of deionized water and stir until completely dissolved to obtain a metal ion solution. Mix 20 mL of TiO2-SiO2 hydrosol with 10 mL of the metal ion solution and stir at 500 r / min at room temperature for 30 min to ensure uniform dispersion to obtain a mixed solution. Then, adjust the pH to 7 with 1 mol / L ammonia water at a dropping rate of 0.5 mL / min and let it stand at room temperature for 2 h until it is completely gelled. The solution does not flow and there is no liquid dripping when the bottle is inverted. After gelation, continue to let it stand for 24 h to obtain an aged wet gel.

[0051] S3. The aged wet gel was immersed in deionized water and solvent exchanged at room temperature for 24 hours, during which the deionized water was replaced once to remove impurities such as residual ethanol and ammonia, resulting in a solvent-exchanged gel. The volume ratio of deionized water to the aged wet gel was 5:1. Subsequently, the solvent-exchanged gel was placed in a freeze dryer and dried under vacuum at -50°C for 24 hours to obtain a metal ion-modified amino-modified TiO2-SiO2 aerogel, denoted as Cu-TiO2-SiO2 aerogel.

[0052] Comparative Example 3 A method for preparing metal ion modified TiO2-SiO2 aerogel is the same as that for Comparative Example 2, except that CuCl2 in S2 is replaced with AlCl3 to obtain metal ion modified TiO2-SiO2 aerogel, denoted as Al-TiO2-SiO2 aerogel.

[0053] Comparative Example 4 A method for preparing metal ion modified TiO2-SiO2 aerogel is the same as that for Comparative Example 2, except that CuCl2 in S2 is replaced with ZnCl2 to obtain metal ion modified TiO2-SiO2 aerogel, denoted as Zn-TiO2-SiO2 aerogel.

[0054] Comparative Example 5 A method for preparing metal ion modified TiO2-SiO2 aerogel is the same as that for Comparative Example 2, except that CuCl2 in S2 is replaced with FeCl2 to obtain metal ion modified TiO2-SiO2 aerogel, denoted as Fe-TiO2-SiO2 aerogel.

[0055] Depend on Figure 1 It was found that the metal ion modified amino-modified TiO2-SiO2 aerogel of Example 3, the TiO2-SiO2 aerogel of Comparative Example 1, and the metal ion modified TiO2-SiO2 aerogel of Comparative Example 4 all exhibited an amorphous state, indicating that their particle size was very small and they were nanomaterials.

[0056] Depend on Figure 2 The observed peaks for Zn and N indicate that Zn 2+ Successful doping and successful amino modification.

[0057] Depend on Figure 3 It was observed that after 200℃, the TiO2-SiO2 aerogel of Comparative Example 1 showed almost no weight loss, while the metal ion-modified amino-modified TiO2-SiO2 aerogel of Example 3 and the metal ion-modified TiO2-SiO2 aerogel of Comparative Example 4 exhibited continuous weight loss within the temperature range of 200℃ to 600℃. This weight loss characteristic is attributed to the decomposition of metal ion-coordinated water and amino functional groups. Compared with Comparative Example 1, the number of surface functional groups in Examples 3 and 4 was significantly increased, providing more Sr. 2+ The adsorption active sites are beneficial to enhancing the aerogel's ability to capture strontium ions.

[0058] Depend on Figure 4 The specific surface area of ​​the TiO2-SiO2 aerogel in Comparative Example 1 was found to be 46.6 μm. 2 / g, the specific surface area of ​​the metal ion modified TiO2-SiO2 aerogel in Comparative Example 4 is 462.8 μm. 2 / g, the specific surface area of ​​the metal ion-modified amino-modified TiO2-SiO2 aerogel in Example 3 is 416.2m². 2 The concentration of Zn / g indicates that Zn doping significantly increases the specific surface area of ​​a single TiO2-SiO2 aerogel. The pore volume of the TiO2-SiO2 aerogel in Comparative Example 1 is 0.027 cm³ / g. 3 / g, the pore volume of the metal ion-modified TiO2-SiO2 aerogel in Comparative Example 4 is 0.290 cm³ / g. 3 / g, the pore volume of the metal ion-modified amino-modified TiO2-SiO2 aerogel in Example 3 is 0.230 cm³. 3 / g; The average pore size of the TiO2-SiO2 aerogel in Comparative Example 1 was 17.05 nm, the average pore size of the metal ion modified TiO2-SiO2 aerogel in Comparative Example 4 was 1.69 nm, and the pore volume of the metal ion modified amino-modified TiO2-SiO2 aerogel in Example 3 was 1.41 nm. The increase in pore volume and the decrease in pore size contribute to the growth of Sr 2+ Transport during the adsorption process enhances adsorption performance.

[0059] Depend on Figure 5 The results showed that the surface of the TiO2-SiO2 aerogel in Comparative Example 1 was relatively smooth, while the surfaces of the metal ion-modified TiO2-SiO2 aerogel in Comparative Example 4 and the metal ion-modified amino-modified TiO2-SiO2 aerogel in Example 3 were rough, which was beneficial for Sr 2 + The capture.

[0060] application: Sr 2+ Adsorption performance test: Using the metal ion modified amino-modified TiO2-SiO2 aerogels of Examples 1-4, the TiO2-SiO2 aerogel of Comparative Example 1, and the metal ion modified TiO2-SiO2 aerogels of Comparative Examples 2-5 as aerogel samples, the nine aerogel samples were placed in an atmosphere containing Sr. 2+ In simulated wastewater (with uniform initial mass concentration, temperature, and other conditions), the adsorption effect of each aerogel sample on Sr was determined according to the standard adsorption experimental procedure (such as oscillatory adsorption, centrifugal separation, and atomic absorption spectroscopy detection). 2+ The adsorption efficiency and adsorption capacity were compared, and the effects of different metal ion doping and amino modification on the adsorption performance were investigated.

[0061] Depend on Figure 6 It was found that when the mass concentration of Sr was 10 mg / L, the adsorption efficiency of the metal ion modified amino-modified TiO2-SiO2 aerogel of Example 3 of the present invention reached 98.6%, and when the mass concentration of Sr was 100 mg / L, the adsorption efficiency reached 79.2%, which far exceeded that of existing adsorption materials (the reported conventional materials such as TiO2 have an adsorption efficiency of 85% when the mass concentration of Sr is 10 mg / L, and 85% when the mass concentration of Sr is 100 mg / L).

[0062] Depend on Figure 7 It was found that when the Sr mass concentration was 10 mg / L, the metal ion-modified amino-modified TiO2-SiO2 aerogel of Example 3 of this invention reached adsorption equilibrium after 100 min of adsorption, exhibiting excellent surface adsorption kinetics performance. This rapid adsorption characteristic is beneficial for shortening the actual wastewater treatment cycle and improving treatment efficiency. Furthermore, the adsorption process conforms to a pseudo-second-order kinetic model, indicating that the adsorption is chemisorption.

[0063] Depend on Figure 8 The results show that the saturated adsorption capacity of the metal ion-modified amino-modified TiO2-SiO2 aerogel in Example 3 of this invention is significantly better than that of the TiO2-SiO2 aerogel in Comparative Example 1 and the metal ion-modified TiO2-SiO2 aerogel in Comparative Example 4. This fully verifies that the synergistic modification strategy of "metal ion doping-amino modification" can improve the adsorption capacity of Sr. 2+ Feasibility and superiority in terms of adsorption performance. This synergistic effect is achieved through Zn. 2+ Regulation of surface charge properties of amino-modified TiO2-SiO2 aerogel by metal ion modification and the effect of amino functional groups on Sr 2+ The specific coordination effect effectively increases the number of active adsorption sites and enhances adsorption affinity.

[0064] Furthermore, the adsorption process conforms to the Langmuir isotherm model, and the active sites on the surface of the metal ion-modified amino-modified TiO2-SiO2 aerogel in Example 3 of this invention are uniformly distributed, and Sr 2+ It is uniformly adsorbed in the form of a monolayer on the surface of metal ion-modified amino-modified TiO2-SiO2 aerogel, and there is no interaction between the adsorption sites.

[0065] like Figure 9 As shown, the metal ion-modified amino-modified TiO2-SiO2 aerogel of Example 3 of the present invention is almost unaffected by Na+. + K + Mg 2+ The effects of coexistence only occur at high concentrations of Ca. 2+ The adsorption efficiency decreases slightly when Zn is present, proving that Zn 2+ Synergistic modification with amino groups enhances the adhesion of TiO2-SiO2 aerogel to Sr. 2+ The selectivity further demonstrates that the metal ion-modified amino-modified TiO2-SiO2 aerogel of the present invention has excellent ion selectivity and reliability in practical applications.

[0066] Depend on Figure 10 The results show that the metal ion-modified amino-modified TiO2-SiO2 aerogel of Example 3 of this invention exhibits excellent adsorption performance under simulated actual water quality conditions: Sr in surface water and tap water... 2+ The adsorption efficiencies reached 75.9% and 70.3%, respectively. Although slightly lower than the adsorption efficiency in deionized water (79.2%), the decrease was limited (<10%). This result indicates that the metal ion-modified amino-modified TiO2-SiO2 aerogel of this invention exhibits good tolerance and adaptability to complex water environments (containing multiple coexisting ions and organic impurities). Its "metal ion-amino" synergistic adsorption mechanism can effectively resist the interference of competing ions in actual water bodies and maintain a high Sr content. 2+ Selective capture capability. The above performance fully demonstrates Zn 2+ TiO2-SiO2 aerogels synergistically modified with amino groups have significant application potential and engineering value in practical treatment scenarios of radioactive strontium wastewater.

[0067] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for preparing a metal ion-modified amino-modified TiO2-SiO2 aerogel, characterized in that, Includes the following steps: Using TiO2-SiO2 hydrosol as a substrate and metal chloride and 1,3-propanediamine as modifiers, the aqueous solutions of metal chloride, TiO2-SiO2 hydrosol and 1,3-propanediamine were mixed, the pH was adjusted to 7-8, and then subjected to gelation-aging treatment to obtain aged wet gel. The aged wet gel was immersed in water and subjected to solvent exchange, followed by freeze drying to obtain metal ion-modified amino-modified TiO2-SiO2 aerogel.

2. The preparation method according to claim 1, characterized in that, The volume ratio of the aqueous solution of metal chloride, the aqueous solution of TiO2-SiO2 sol, and the aqueous solution of 1,3-propanediamine is 1:1 to 2:

1. In the aqueous solution of 1,3-propanediamine, the mass fraction of 1,3-propanediamine is 0.5%~1.5%; in the aqueous solution of metal chloride, the concentration of metal ions is 0.2 mol / L.

3. The preparation method according to claim 1, characterized in that, The metal ions in the aqueous solution of metal chloride are selected from Cu. 2+ Al 3+ Zn 2+ or Fe 2+ .

4. The preparation method according to claim 1, characterized in that, The pH was adjusted using ammonia solution with a concentration of 0.5 mol / L to 2 mol / L.

5. The preparation method according to claim 1, characterized in that, The gelation-aging process is as follows: first, let it stand at room temperature for 2 to 4 hours until it is completely gelled, and then continue to stand for at least 24 hours until it is aged.

6. The preparation method according to claim 1, characterized in that, The volume ratio of water to aged wet gel is 2~5:

1.

7. The preparation method according to claim 1, characterized in that, The freeze-drying conditions are: vacuum drying at -50℃ to -40℃ for at least 24 hours.

8. The preparation method according to claim 1, characterized in that, TiO2-SiO2 hydrosol was prepared according to the following steps: Tetrabutyl orthosilicate and tetrabutyl titanate were dissolved together in ethanol and then mixed with water to obtain TiO2-SiO2 hydrosol; wherein the molar ratio of tetrabutyl orthosilicate to tetrabutyl titanate was 1~2:1, and the mass-volume ratio of tetrabutyl orthosilicate to water was 2.5g:2mL~3mL.

9. A metal ion-modified amino-modified TiO2-SiO2 aerogel prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the metal ion-modified amino-modified TiO2-SiO2 aerogel according to claim 1 in the preparation of a radioactive strontium ion adsorbent.

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