A sodium alginate-gelatin composite porous antibacterial hydrogel spherical uranium adsorption material containing a phosphoric acid group and a preparation method thereof

Abstract

The application discloses a phosphorus acid group-containing sodium alginate-gelatin composite porous antibacterial hydrogel ball uranium adsorption material and a preparation method thereof, and relates to a uranium adsorption material and a preparation method thereof. In order to solve the problems of the existing amido oxime group materials for uranium adsorption, i.e., the reduction of adsorption sites due to the excessive combination of amido oxime groups and cross-linking agents, the reduction of adsorption capacity, the reduction of adsorption rate and the reduction of selectivity, the application firstly introduces gelatin and polyamide into sodium alginate to form a sodium alginate-polyamide-gelatin gel system. Then, the gel ball is grafted with phosphorus to strengthen the uranium adsorption effect. Finally, the gel ball is quaternized by iodomethane to enhance the antibacterial performance of the material. The prepared gel ball has the advantages of a relatively rich reticular porous structure, good mechanical performance, more adsorption sites, a high uranium adsorption capacity and certain antibacterial performance, and has a wide development prospect.

Description

Technical Field

[0001] This invention relates to a uranium adsorption material and its preparation method, specifically to a sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups and its preparation method. Background Technology

[0002] As society develops, human demand for energy is gradually increasing, and the finite nature of energy has become a significant factor limiting social development. In recent years, nuclear energy, as one of the clean energy sources, has received increasing attention. Its high energy density and low carbon emissions are more in line with the needs of sustainable energy development.

[0003] Uranium is the primary nuclear fuel required for nuclear power generation, and a stable supply of uranium resources is essential for the sustainable development of nuclear energy. To date, all countries have used uranium fuel from terrestrial uranium mines for nuclear energy development. However, the proven terrestrial uranium reserves (7.6 million tons) are insufficient to sustain the rapid development of nuclear energy worldwide, and uranium resources will be depleted within 100 years. Exploring sufficient and stable uranium resources is key to solving the current predicament of nuclear energy development. Research has found that the ocean contains abundant uranium resources, with total reserves of approximately 4.5 billion tons, more than 1,000 times the combined terrestrial uranium reserves of all countries. Furthermore, the ocean receives approximately 27,000 tons of uranium annually from river flows. If these marine uranium resources can be effectively extracted, they could support global nuclear fuel consumption for the next 10,000 years, providing a new approach to solving the current energy crisis facing humanity.

[0004] Currently, amine oxime-based materials for uranium adsorption have been widely applied and developed. These materials mainly utilize the unbonded lone pair electrons of the oxime oxygen atom and amino nitrogen atom in the amine oxime group to coordinate with uranium ions, forming stable chelates and thus achieving efficient uranium adsorption. Among them, amine oxime-modified fibers are a common type of uranium adsorption material. They are typically produced by treating polyacrylonitrile (PAN) fibers or resins with hydroxylamine (such as hydroxylamine hydrochloride) to convert the cyano groups into amine oxime groups. Both amine oxime-based chelating resins and amine oxime-modified fibers can form stable chelate products with uranium ions; therefore, amine oxime-based chelating resins are also frequently used for uranium adsorption. Besides fibers and resins, amine oxime groups can also be introduced into polymer materials, such as PVA and chitosan. These materials also exhibit good uranium adsorption performance.

[0005] Although amine oxime-based adsorbents exhibit high adsorption efficiency for uranium, a problem remains: excessive binding of the amine oxime groups to the crosslinking agent reduces the number of adsorption sites. When the amine oxime groups excessively bind to the crosslinking agent, sites that could otherwise be used to adsorb uranium ions may be occupied or masked, resulting in a reduction in the number of effective adsorption sites. This means the material's adsorption capacity may decrease, failing to adequately capture uranium ions in solution. Besides reducing adsorption sites, excessive crosslinking can also alter the material's pore structure. This can lead to narrowing or disordering of the pores, affecting the diffusion and transport of uranium ions within the material. Uranium ions must overcome greater diffusion resistance to reach the adsorption sites, thus reducing the adsorption rate and efficiency. In summary, excessive binding of the amine oxime groups to the crosslinking agent leads to a significant decrease in the material's adsorption performance. This manifests not only as a reduction in adsorption capacity but may also include a decrease in adsorption rate and selectivity. Summary of the Invention

[0006] To address the problem that existing amylopectin-based materials used for uranium adsorption suffer from reduced adsorption sites due to excessive binding of amylopectin groups to crosslinking agents, resulting in decreased adsorption capacity, lower adsorption rate, and reduced selectivity, this invention proposes a uranium adsorption material composed of phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres and its preparation method.

[0007] The structural formula of the sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups of the present invention is as follows:

[0008]

[0009] The preparation method of the above-mentioned sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups is carried out according to the following steps:

[0010] I. Synthesis of elastic gel balls using sodium alginate, gelatin, and polyamide as raw materials:

[0011] A mixture of gelatin aqueous solution and polyamide aqueous solution was added to sodium alginate aqueous solution to obtain a mixed solution. The mixed solution was mechanically stirred and allowed to stand to remove air bubbles. Then, under magnetic stirring, the gel solution was dropped into crosslinking agent solution I using a syringe to crosslink and form gel spheres. After forming, the gel spheres were filtered and washed. Then, the obtained gel spheres were shaken and soaked in crosslinking agent solution II for secondary crosslinking and forming. Finally, they were filtered and washed to obtain elastic gel spheres.

[0012] The mass ratio of sodium alginate to polyamide is 0.4-0.6:0.65-0.85;

[0013] The mass ratio of sodium alginate to gelatin is 0.4-0.6:2.3-2.7;

[0014] 2. Phosphorylate the elastic gel spheres obtained in step one to obtain phosphate-grafted elastic gel spheres:

[0015] The elastic gel spheres prepared in step one were washed with hydrochloric acid and deionized water respectively to remove calcium ions. The washed gel spheres were dissolved in deionized water, and then glyphosate was added and magnetically stirred. Then N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added and reacted in a water bath. Finally, the mixture was filtered and washed to obtain phosphate-grafted elastic gel spheres.

[0016] The mass ratio of sodium alginate to glyphosate is 0.4-0.6:1.5-3.0;

[0017] The mass ratio of sodium alginate to N-hydroxysuccinimide is 0.4-0.6:0.5-0.8;

[0018] The mass ratio of sodium alginate to 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 0.4-0.6:1.0-1.5;

[0019] 3. Quaternize the phosphate-grafted elastic gel spheres obtained in step 2 to obtain quaternized phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material:

[0020] The method for quaternizing the acid-grafted elastic gel spheres is as follows: the phosphate-grafted elastic gel spheres obtained in step two are mixed with methanol and solid sodium hydroxide. After the phosphate-grafted elastic gel spheres swell, iodomethane is added. Then, the mixture is placed in a constant temperature shaker and shaken at room temperature. After the reaction is completed, the gel spheres are soaked in deionized water. After the reaction is completed, quaternized acid-grafted elastic gel spheres are obtained, which are phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres uranium adsorption materials.

[0021] The mass ratio of sodium alginate to methanol is 0.4-0.6 g: 20-40 mL;

[0022] The mass ratio of sodium alginate to solid sodium hydroxide is 0.4-0.6:0.15-0.3;

[0023] The mass ratio of sodium alginate to the volume ratio of iodomethane is 0.4-0.6 g : 5-7 mL.

[0024] The principle and beneficial effects of this invention are as follows:

[0025] 1. The sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material of this invention contains abundant phosphate functional groups, exhibiting excellent adsorption capacity for uranium, with high adsorption rate and uranium ion selectivity; in Na... + K + Cu 2+ Mg2+ Co 2+ 、Sr 2+ Ba 2+ Ca 2+ It exhibits high selective adsorption of uranium ions in aqueous solutions containing coexisting ions. The optimal combined adsorption capacity is achieved when the gelatin addition is 2.5 g and the solid-liquid ratio of the uranium adsorbent to the uranium solution is 0.5, resulting in an adsorption capacity of 581.46 mg / g for uranium ions in a uranium solution with a concentration of C0 = 100 ppm and pH = 6. -1 above.

[0026] 2. This invention introduces gelatin to form a sodium alginate-polyamide-gelatin gel system (SA-HA-Gel). The triple helix structure of the gelatin molecules makes the gel spheres more elastic. Furthermore, the adsorbent material gel spheres successfully prepared by the two-step molding method of ionic crosslinking and covalent crosslinking and the means of grafting modification have higher stability, can reduce wear during adsorption, and maintain low loss under ionic solutions and stirring.

[0027] 3. This invention grafts bio-phosphorus sulfate (BPG) onto gel spheres to enhance uranium adsorption: Bio-phosphorus sulfate (BPG) is a small molecule compound with diphosphate, tertiary amine, and carboxyl groups. It can be grafted onto the gel through condensation of the carboxyl groups with numerous amino groups in gelatin and polyamide. The phosphate groups are another group with a high binding capacity for uranium, and the tertiary amine nitrogen atom supports quaternization modification. Finally, quaternization of the gel spheres with iodomethane enhances the material's antibacterial properties, exhibiting excellent inhibitory ability against Escherichia coli and Staphylococcus aureus. Furthermore, its effective adsorption in real seawater demonstrates its ability to maintain uranium extraction capacity under the interference of multiple microorganisms.

[0028] 4. The phosphate-grafted elastic antibacterial porous network gel sphere uranium adsorbent material prepared in this invention is used for uranium extraction from seawater. The porous network structure of the gel spheres, composed of gelatin and hyperbranched polyamide, optimizes its mechanical properties, and the quaternary ammonium salt modification endows it with certain antibacterial ability.

[0029] 5. The amino groups on gelatin are the main grafting groups for glyphosate. A higher gelatin content provides sufficient grafting sites, resulting in more phosphate groups on the surface of the adsorbent material. Further increases in gelatin content provide even more grafting sites, leading to the grafting of more glyphosate. However, the supply of glyphosate is insufficient to cover all available grafting sites. Simultaneously, this increase also leads to a relative decrease in the concentration of glyphosate, which may negatively impact adsorption performance. Therefore, the supply of glyphosate also limits the comprehensiveness of grafting. The amount of gelatin used in this application is optimal, providing more grafting sites while ensuring that the supply of glyphosate is sufficient to cover all available grafting sites, thus guaranteeing adsorption performance. Attached Figure Description

[0030] Figure 1 The sodium alginate (SA), gelatin (Gel), biphosphoric acid phosphate (BPG), phosphorylated gel spheres (BPG-SHG), and phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres uranium adsorption material (Anti-BPG / SHG) are described in Example 1. 2.5 Infrared spectrum of )

[0031] Figure 2 For Anti-BPG / SHG 0.5 Anti-BPG / SHG 2.5 and Anti-BPG / SHG 3.5 Scanning electron microscope image;

[0032] Figure 3 pH affects Anti-BPG / SHG 2.5 The effect of uranium adsorption capacity on the adsorption capacity is shown in the figure.

[0033] Figure 4 The effect of adsorbent dosage on Anti-BPG / SHG 2.5 The effect of uranium adsorption performance is shown in the figure.

[0034] Figure 5 Is it the contact time for Anti-BPG / SHG? 2.5 The effect of uranium adsorption performance is shown in the figure. Detailed Implementation

[0035] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0036] Specific Implementation Method 1: The structural formula of the uranium adsorbent spheres containing phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres in this implementation method is as follows:

[0037]

[0038] This embodiment has the following beneficial effects:

[0039] 1. The sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups in this embodiment contains abundant phosphate functional groups, exhibiting excellent adsorption capacity for uranium, with high adsorption rate and uranium ion selectivity; in Na + K + Cu 2+ Mg 2+ Co 2+ 、Sr 2+ Ba 2+ Ca 2+It exhibits high selective adsorption of uranium ions in aqueous solutions containing coexisting ions. The optimal combined adsorption capacity is achieved when the gelatin addition is 2.5 g and the solid-liquid ratio of the uranium adsorbent to the uranium solution is 0.5, resulting in an adsorption capacity of 581.46 mg / g for uranium ions in a uranium solution with a concentration of C0 = 100 ppm and pH = 6. -1 above.

[0040] 2. This embodiment introduces gelatin to form a sodium alginate-polyamide-gelatin gel system (SA-HA-Gel). The triple helix structure of gelatin molecules makes the gel spheres more elastic. Furthermore, the adsorbent material gel spheres successfully prepared by the two-step molding method of ionic crosslinking and covalent crosslinking and the grafting modification method have higher stability, can reduce wear during adsorption, and maintain low loss under ionic solution and stirring.

[0041] 3. In this embodiment, phosphate-enhanced phosphorus (BPG) is grafted onto the gel spheres to enhance uranium adsorption. BPG is a small molecule compound with diphosphate, tertiary amine, and carboxyl groups. It can be grafted onto the gel through condensation of the carboxyl groups with a large number of amino groups in gelatin and polyamide. The phosphate group is another group with a high binding capacity for uranium, and the tertiary amine nitrogen atom supports quaternization modification. Finally, quaternization of the gel spheres with iodomethane enhances the antibacterial properties of the material, exhibiting excellent inhibitory ability against Escherichia coli and Staphylococcus aureus. Furthermore, its effective adsorption in real seawater demonstrates its ability to maintain uranium extraction capacity under the interference of multiple microorganisms.

[0042] 4. The phosphate-grafted elastic antibacterial porous network gel sphere uranium adsorbent material prepared in this embodiment is used for uranium extraction from seawater. The porous network structure of the gel spheres composed of gelatin and hyperbranched polyamide optimizes its mechanical properties, and the quaternary ammonium salt modification endows it with certain antibacterial ability.

[0043] 5. The amino groups on gelatin are the main grafting groups for glyphosate. A higher gelatin content provides sufficient grafting sites, resulting in more phosphate groups on the surface of the adsorbent material. Further increases in gelatin content provide even more grafting sites, leading to the grafting of more glyphosate. However, the supply of glyphosate is insufficient to cover all available grafting sites. Simultaneously, this increase also leads to a relative decrease in the concentration of glyphosate, which may negatively impact adsorption performance. Therefore, the supply of glyphosate also limits the comprehensiveness of grafting. In this embodiment, the amount of gelatin used is optimal, providing more grafting sites while ensuring that the supply of glyphosate is sufficient to cover all available grafting sites, thus guaranteeing adsorption performance.

[0044] Specific Implementation Method Two: The preparation method of the phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material in this implementation method is carried out according to the following steps:

[0045] I. Synthesis of elastic gel balls using sodium alginate, gelatin, and polyamide as raw materials:

[0046] A mixture of gelatin aqueous solution and polyamide aqueous solution was added to sodium alginate aqueous solution to obtain a mixed solution. The mixed solution was mechanically stirred and allowed to stand to remove air bubbles. Then, under magnetic stirring, the gel solution was dropped into crosslinking agent solution I using a syringe to crosslink and form gel spheres. After forming, the gel spheres were filtered and washed. Then, the obtained gel spheres were shaken and soaked in crosslinking agent solution II for secondary crosslinking and forming. Finally, they were filtered and washed to obtain elastic gel spheres.

[0047] The mass ratio of sodium alginate to polyamide is 0.4-0.6:0.65-0.85;

[0048] The mass ratio of sodium alginate to gelatin is 0.4-0.6:2.3-2.7;

[0049] 2. Phosphorylate the elastic gel spheres obtained in step one to obtain phosphate-grafted elastic gel spheres:

[0050] The elastic gel spheres prepared in step one were washed with hydrochloric acid and deionized water respectively to remove calcium ions. The washed gel spheres were dissolved in deionized water, and then glyphosate was added and magnetically stirred. Then N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added and reacted in a water bath. Finally, the mixture was filtered and washed to obtain phosphate-grafted elastic gel spheres.

[0051] The mass ratio of sodium alginate to glyphosate is 0.4-0.6:1.5-3.0;

[0052] The mass ratio of sodium alginate to N-hydroxysuccinimide is 0.4-0.6:0.5-0.8;

[0053] The mass ratio of sodium alginate to 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 0.4-0.6:1.0-1.5;

[0054] 3. Quaternize the phosphate-grafted elastic gel spheres obtained in step 2 to obtain quaternized phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material:

[0055] The method for quaternizing the acid-grafted elastic gel spheres is as follows: the phosphate-grafted elastic gel spheres obtained in step two are mixed with methanol and solid sodium hydroxide. After the phosphate-grafted elastic gel spheres swell, iodomethane is added. Then, the mixture is placed in a constant temperature shaker and shaken at room temperature. After the reaction is completed, the gel spheres are soaked in deionized water. After the reaction is completed, quaternized acid-grafted elastic gel spheres are obtained, which are phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres uranium adsorption materials.

[0056] The mass ratio of sodium alginate to methanol is 0.4-0.6 g: 20-40 mL;

[0057] The mass ratio of sodium alginate to solid sodium hydroxide is 0.4-0.6:0.15-0.3;

[0058] The mass ratio of sodium alginate to the volume ratio of iodomethane is 0.4-0.6 g : 5-7 mL.

[0059] This embodiment has the following beneficial effects:

[0060] 1. The sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups in this embodiment contains abundant phosphate functional groups, exhibiting excellent adsorption capacity for uranium, with high adsorption rate and uranium ion selectivity; in Na + K + Cu 2+ Mg 2+ Co 2+ 、Sr 2+ Ba 2+ Ca 2+ It exhibits high selective adsorption of uranium ions in aqueous solutions containing coexisting ions. The optimal combined adsorption capacity is achieved when the gelatin addition is 2.5 g and the solid-liquid ratio of the uranium adsorbent to the uranium solution is 0.5, resulting in an adsorption capacity of 581.46 mg / g for uranium ions in a uranium solution with a concentration of C0 = 100 ppm and pH = 6. -1 above.

[0061] 2. This embodiment introduces gelatin to form a sodium alginate-polyamide-gelatin gel system (SA-HA-Gel). The triple helix structure of gelatin molecules makes the gel spheres more elastic. Furthermore, the adsorbent material gel spheres successfully prepared by the two-step molding method of ionic crosslinking and covalent crosslinking and the grafting modification method have higher stability, can reduce wear during adsorption, and maintain low loss under ionic solution and stirring.

[0062] 3. In this embodiment, phosphate-enhanced phosphorus (BPG) is grafted onto the gel spheres to enhance uranium adsorption. BPG is a small molecule compound with diphosphate, tertiary amine, and carboxyl groups. It can be grafted onto the gel through condensation of the carboxyl groups with a large number of amino groups in gelatin and polyamide. The phosphate group is another group with a high binding capacity for uranium, and the tertiary amine nitrogen atom supports quaternization modification. Finally, quaternization of the gel spheres with iodomethane enhances the antibacterial properties of the material, exhibiting excellent inhibitory ability against Escherichia coli and Staphylococcus aureus. Furthermore, its effective adsorption in real seawater demonstrates its ability to maintain uranium extraction capacity under the interference of multiple microorganisms.

[0063] 4. The phosphate-grafted elastic antibacterial porous network gel sphere uranium adsorbent material prepared in this embodiment is used for uranium extraction from seawater. The porous network structure of the gel spheres composed of gelatin and hyperbranched polyamide optimizes its mechanical properties, and the quaternary ammonium salt modification endows it with certain antibacterial ability.

[0064] 5. The amino groups on gelatin are the main grafting groups for glyphosate. A higher gelatin content provides sufficient grafting sites, resulting in more phosphate groups on the surface of the adsorbent material. Further increases in gelatin content provide even more grafting sites, leading to the grafting of more glyphosate. However, the supply of glyphosate is insufficient to cover all available grafting sites. Simultaneously, this increase also leads to a relative decrease in the concentration of glyphosate, which may negatively impact adsorption performance. Therefore, the supply of glyphosate also limits the comprehensiveness of grafting. In this embodiment, the amount of gelatin used is optimal, providing more grafting sites while ensuring that the supply of glyphosate is sufficient to cover all available grafting sites, thus guaranteeing adsorption performance.

[0065] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that: the crosslinking agent solution I mentioned in step one is a calcium chloride solution with a mass fraction of 2-4%; the crosslinking time in the crosslinking agent solution I is 1-3 hours.

[0066] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Two in that: the crosslinking agent solution II mentioned in step one is a glutaraldehyde solution with a mass fraction of 1-4%; the crosslinking molding time of the crosslinking agent solution II is 7-9 hours.

[0067] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Two in that the mechanical stirring speed in step one is 500-700 r·min. -1 The time is 20-30 minutes.

[0068] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Two in that the temperature of the deionized water used in the preparation of the gelatin aqueous solution in step one is 50-60℃.

[0069] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Two in that: the concentration of hydrochloric acid in step two is 0.1-0.2 mol / L, and the hydrochloric acid washing time is 20-30 min; after the hydrochloric acid washing is completed, deionized water is used for washing 3 times, and the time for each deionized water washing is 10-15 min.

[0070] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Two in that the temperature of the water bath reaction in step two is 50-70℃ and the time is 5-7h.

[0071] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Two in that the time for room temperature oscillation in the constant temperature shaker described in step three is 10-14 hours.

[0072] Specific Implementation Method 10: This implementation method differs from Specific Implementation Method 2 in that the gel balls described in step 3 are soaked in deionized water for 2-4 hours, and the deionized water is replaced every 1-2 hours during this period.

[0073] Experimental Example 1

[0074] The preparation method of the uranium adsorbent material containing phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres in this embodiment is carried out according to the following steps:

[0075] Step 1: Accurately weigh 0.5g of sodium alginate (SA) and add it to a 50mL beaker. Add 10mL of deionized water and stir until dissolved to obtain a sodium alginate (SA) solution. Weigh 2.5g of gelatin into a 25mL beaker and add 10mL of 60℃ deionized water. Stir until dissolved to obtain a gelatin (Gel) solution. Weigh 0.75g of polyamide (HA) and sonicate it into 5mL of deionized water to obtain a polyamide (HA) solution.

[0076] A mixed solution was obtained by adding gelatin (Gel) solution and polyamide (HA) solution to sodium alginate (SA) solution, and the solution was stirred at a speed of 500 r·min. -1 Under the conditions of mechanical stirring for 20 min, the mixture was allowed to stand to remove air bubbles. Under magnetic stirring, the mixed solution was dropped into a 2.5 wt.% calcium chloride solution using a 1 mL syringe for cross-linking and molding for 2 h. The mixture was then filtered and washed three times with deionized water. The resulting gel balls were then immersed in a 2% glutaraldehyde (GA) solution for secondary cross-linking and molding for 8 h. Finally, the mixture was filtered and washed three times with deionized water to obtain elastic gel balls (SA-HA-Gel).

[0077] Step 2: Wash the elastic gel spheres (SA-HA-Gel) prepared in Step 1 in 50 mL of 0.1 mol / L HCl solution for 20 min, then wash three times with deionized water for 10 min each time. Place the calcium-removed gel spheres in a 50 mL round-bottom flask, add 20 mL of deionized water, accurately add 2.0 g of phosphate grafted polyphosphate (BPG) to the flask and stir magnetically for 4 h. At the same time, accurately weigh 0.63 g of N-hydroxysuccinimide (NHS) and 1.25 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), add them to the flask after stirring, and heat in a water bath to 60 °C for 5 h. After that, filter and wash with deionized water to obtain phosphate-grafted elastic gel spheres (BPG-SHG).

[0078] Step 3: Place the phosphate-grafted elastic gel spheres prepared in Step 2 into a 100mL Erlenmeyer flask, add 30mL of methanol and 0.2g of solid NaOH. After the gel spheres swell, add 6mL of iodomethane. Completely wrap the Erlenmeyer flask with tin foil and place it in a constant temperature shaker at room temperature (25℃) for 12 hours. After the reaction is complete, soak the gel spheres in 500mL of deionized water for 3 hours, changing the water every hour, to obtain phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material (Anti-BPG / SHG). 2.5 Freeze-dry for later use.

[0079] The structural formula of the phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material prepared in this embodiment is as follows:

[0080]

[0081] Figure 1 The sodium alginate (SA), gelatin (Gel), biphosphoric acid phosphate (BPG), phosphorylated gel spheres (BPG-SHG), and phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres uranium adsorption material (Anti-BPG / SHG) are described in Example 1. 2.5 The infrared spectrum of SA; the characteristic peak of SA's infrared spectrum is at 1626 cm⁻¹. -1 and 1413cm -1 They belong to the ionized carboxyl group (-COO) - Symmetric and asymmetric stretching vibrations of Gel; the infrared spectrum of Gel at 1535 cm⁻¹ -1 and 1330cm -1 The peaks for the NH bending and CN stretching vibrations of primary amines are shown at 1626 cm⁻¹. -1 and 1413cm -1 The characteristic peak of the carboxyl group was observed at 1240-1090 cm⁻¹, indicating that gelatin contains both amino and carboxyl groups; the infrared spectrum of BPG is in the range of 1240-1090 cm⁻¹. -1 and 879cm -1 Characteristic peaks are displayed at 1240 cm⁻¹, corresponding to vibrations at P=O and POH, respectively. After grafting BPG-SHG with Anti-BPG / SHG, characteristic peaks are observed at 1240 cm⁻¹. -1 The appearance of a broad peak at 1450 cm⁻¹ indicates successful BPG grafting. Anti-BPG / SHG is similar to BPG-SHG, but after quaternization, it shows a peak at 1450 cm⁻¹. -1 The newly added peak indicates that the quaternary ammonium salt group reacted successfully. Therefore, Figure 1 This demonstrates the successful preparation of Anti-BPG / SHG gel ball adsorbents.

[0082] Experimental Example 2

[0083] This embodiment differs from Experimental Example 1 in that, in step one, 0.5 g of gelatin was weighed into a 25 mL beaker, and 10 mL of 60 °C deionized water was added and stirred until dissolved to obtain a gelatin (Gel) solution; other steps and parameters were the same as in Experimental Example 1. Experimental Example 2 prepared a sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorbent material containing phosphate groups (Anti-BPG / SHG). 2.5 )

[0084] Experimental Example 3

[0085] This embodiment differs from Experimental Example 1 in that, in step one, 3.5g of gelatin was weighed into a 25mL beaker, and 10mL of 60℃ deionized water was added and stirred until dissolved to obtain a gelatin (Gel) solution; other steps and parameters were the same as in Experimental Example 1. Experimental Example 3 prepared a sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorbent material containing phosphate groups (Anti-BPG / SHG). 3.5 )

[0086] Figure 2 For Anti-BPG / SHG 0.5 Anti-BPG / SHG 2.5 and Anti-BPG / SHG 3.5 Scanning electron microscope image; When a small amount of gelatin is added, the gel adheres to the gelatin chains due to the gelatin's toughness. Anti-BPG / SHG 0.5 It exhibits a grooved porous structure, characterized by a porous structure combining fibers and lamellar layers. Increasing the gelatin content enhances the properties of Anti-BPG / SHG. 2.5 The porous structure is more pronounced, with abundant and nested pores, due to the full cross-linking of gelatin and HA to form a three-dimensional network. Furthermore, with the addition of large amounts of gelatin, Anti-BPG / SHG... 3.5 The surface becomes smooth and pore-free because excessive gelatin dilutes the HA, hindering the formation of the three-dimensional network, while the gelling ability of gelatin results in a compact structure.

[0087] Uranium adsorption performance evaluation process:

[0088] Preparation of adsorption solution:

[0089] Preparation of Solution 1 (initial uranium solution): Accurately weigh 2.110 g of uranium nitrate hexahydrate using an electronic balance. Transfer the solution to a 250 mL beaker and rinse thoroughly with deionized water several times. Then add 100 mL of deionized water and stir until the uranium nitrate is completely dissolved. Transfer the solution to a 1000 mL volumetric flask and rinse the beaker several times to ensure complete transfer of uranium ions. Add 3-5 drops of concentrated nitric acid to acidify the solution, and dilute to the mark to obtain a uranium solution with a concentration of 1000 ppm. Uranium solutions of different concentrations required for adsorption experiments are obtained by diluting this uranium solution.

[0090] Preparation of Solution 2 (Ion Competition Solution): The steps for preparing the coexisting ion solution required for the ion competition experiment are as follows: Weigh out the same amount of Na as uranyl ions using an electronic balance. + K + Cu 2+ Mg 2+ Co 2+ 、Sr 2+ Ba 2+ Ca 2+ The nitrate was placed in a 250 mL beaker, and 100 mL of deionized water was added to dissolve it. The mixture was sonicated for 15 min until completely dissolved, and then transferred to a 1000 mL volumetric flask and diluted to volume for later use.

[0091] Preparation of Solution 3 (Simulated Seawater): The preparation steps for the simulated seawater required for the experiment are as follows: Accurately weigh 3.33g of simulated sea salt (Tianjin Kemeio Chemical Reagent Co., Ltd.) on an electronic balance and dissolve it in 500mL of deionized water. Sonicate until the solid is completely dissolved in the water. Pour the solution into a 1L volumetric flask, add 100ppm of uranium standard solution 33, and then add water to make up the volume to obtain the simulated seawater solution. Adjust the pH to the range of 8.0-8.4.

[0092] Uranium adsorption experimental method (the uranium adsorption experimental method is the same in subsequent examples and will not be repeated):

[0093] Adsorption solution extraction experiment: 10 mg of dry gel beads adsorbent material was placed in a 150 mL conical flask containing 50 mL of initial uranium solution. The adsorption device was placed in a constant temperature shaker and shaken for a specific time while maintaining a constant temperature. After adsorption, the solution was filtered using a 0.22 mL aqueous syringe filter membrane. The concentration of uranium in the filtrate was determined by ICP-MS. The unit adsorption capacity (Qe, mg) and solution removal rate (Removal Rate, %) of the adsorbent material were calculated using formulas (1) and (2), respectively.

[0094]

[0095] Where C e This represents the concentration of uranyl ions in the solution at adsorption equilibrium, expressed in mg. -1 C0 represents the initial uranium solution concentration, in mg initial concentration. -1 m represents the mass of the adsorbent material in mg, and V represents the volume of the solution in mL.

[0096] 1. Uranium adsorption experiments under different pH environments:

[0097] First, test with 0.5 mol: -1 Na2CO3 solution and 0.5 mol test:-1 The pH values ​​of the diluted 100 ppm uranium solution were adjusted to 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, and 9.0 using HNO3 solution and a pH meter, respectively. Then, 10 mg of dry weight of gel beads adsorbent material was added to 50 mL of uranium solution at each pH value, sealed, and placed in a constant-temperature shaker at 25°C for 24 h of adsorption. After adsorption, the uranium solution was separated by filtration using a 0.22 μm aqueous needle filter membrane. 10 mL of the supernatant was taken before and after adsorption, and the initial and residual concentrations of uranium ions in the solution were determined by ICP-MS. The uranium removal rate was calculated according to formula (2) to investigate the effect of solution pH on uranium ion adsorption.

[0098] Figure 3 pH affects Anti-BPG / SHG 2.5 The effect of uranium adsorption capacity on adsorption capacity; Anti-BPG / SHG 2.5 Adsorption experiments of gel beads in solutions with pH values ​​of 3-9 for 24 h and 48 h showed that the adsorption capacity first increased and then decreased with increasing pH, reaching its highest value (581.46 mg·g⁻¹) at pH = 6. -1 The reason is that the H group of phosphate group changes under acidic conditions. + It is not easily dissociated, reducing the number of negatively charged adsorption sites; under alkaline conditions, uranyl ions form negatively charged ion clusters, which repel the adsorption sites. However, the adsorption capacity does not change much in the pH range of 3-9 (416.90-581.46 mg·g). -1 Furthermore, the adsorption capacity remained high (533.24 mg·g) even at pH=8. -1 This indicates that phosphate groups have good adsorption performance over a wide pH range, making them more suitable for complex environments.

[0099] 2. Effect of adsorption material dosage on adsorption performance

[0100] First, take eight 150mL Erlenmeyer flasks and add 50mL of 100ppm uranium solution (pH=6) to each. Then, accurately weigh 5, 10, 15, 20, 25, 30, 35, and 40mg of dry weight of gel beads as absorbent material and add them sequentially to the uranium solution, controlling the solid-liquid ratio at 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8g of gel beads respectively. -1 Then, the uranium solution was adsorbed at a constant temperature of 25°C for 24 hours. The uranium solution was then separated by filtration using a 0.22°C water-based needle filter membrane. 10 mL of the supernatant was collected before and after adsorption, and the initial and residual uranium concentrations in the solution were determined by ICP-MS. The unit adsorption capacity and overall removal rate were calculated according to formulas (1) and (2).

[0101] Figure 4 The effect of adsorbent dosage on Anti-BPG / SHG 2.5The graph shows the effect of adsorbent dosage on uranium adsorption performance; as the adsorbent dosage increases from 0.05 to 0.4, the uranium removal efficiency rapidly rises from 39.94% to 84.31%, because more adsorbent provides more adsorption sites. When the dosage increases from 0.5 to 0.8, the removal efficiency slowly increases from 93.40% to 98.24%. Meanwhile, Anti-BPG / SHG... 2.5 The adsorption capacity per unit volume of the gel beads ranged from 799.2 mg·g⁻¹. -1 It rapidly decreased to 122.77 mg / g. -1 This is because the increased adsorbent concentration leads to intensified competition for uranium ions on the adsorption surface. Overall, at a solid-liquid ratio of 0.3 g / L, the adsorbent exhibits higher adsorption capacity and uranium removal rate.

[0102] 3. Effect of contact time on adsorption performance and kinetic study

[0103] First, prepare 400 mL of uranium solutions with concentrations of 25 ppm, 50 ppm, and 100 ppm (ppm refers to mass content), respectively. Adjust the pH of the solution to 6.0. Transfer the prepared uranium solutions to 500 mL beakers. Weigh 80 mg of gel ball adsorbent material and quickly add it to the solution while stirring magnetically at 25 m. Draw the solution after timing and filter it using a 0.22 μm aqueous syringe filter. Determine the concentration of the uranium solution using ICP-MS. Calculate the corresponding uranium adsorption capacity according to formula (2-1).

[0104] Figure 5 Is it the contact time for Anti-BPG / SHG? 2.5 The effect of uranium adsorption performance is shown in the figure. The gel spheres rapidly adsorb uranium ions. Adsorption reaches equilibrium after 1440 minutes. The equilibrium adsorption capacities for uranium solutions of 50, 70, and 100 ppm are 157.8, 371.4, and 774.8 mg·g⁻¹, respectively. -1 This shows that the gel spheres can effectively adsorb uranium at different concentrations.

Claims

1. A sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material containing phosphate groups, characterized in that: The structural formula of the uranium adsorbent material, which is a phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere, is as follows:

2. The preparation method of the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups as described in claim 1, characterized in that: The preparation method of uranium adsorbent material containing phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres is carried out according to the following steps: I. Synthesis of elastic gel balls using sodium alginate, gelatin, and polyamide as raw materials: A mixture of gelatin aqueous solution and polyamide aqueous solution was added to sodium alginate aqueous solution to obtain a mixed solution. The mixed solution was mechanically stirred and allowed to stand to remove air bubbles. Then, under magnetic stirring, the gel solution was dropped into crosslinking agent solution I using a syringe to crosslink and form gel spheres. After forming, the gel spheres were filtered and washed. Then, the obtained gel spheres were shaken and soaked in crosslinking agent solution II for secondary crosslinking and forming. Finally, they were filtered and washed to obtain elastic gel spheres. The mass ratio of sodium alginate to polyamide is 0.4-0.6:0.65-0.85; The mass ratio of sodium alginate to gelatin is 0.4-0.6:2.3-2.7; 2. Phosphorylate the elastic gel spheres obtained in step one to obtain phosphate-grafted elastic gel spheres: The elastic gel spheres prepared in step one were washed with hydrochloric acid and deionized water respectively to remove calcium ions. The washed gel spheres were dissolved in deionized water, and then glyphosate was added and magnetically stirred. Then N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added and reacted in a water bath. Finally, the mixture was filtered and washed to obtain phosphate-grafted elastic gel spheres. The mass ratio of sodium alginate to glyphosate is 0.4-0.6:1.5-3.0; The mass ratio of sodium alginate to N-hydroxysuccinimide is 0.4-0.6:0.5-0.8; The mass ratio of sodium alginate to 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 0.4-0.6:1.0-1.5; 3. Quaternize the phosphate-grafted elastic gel spheres obtained in step 2 to obtain quaternized phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel sphere uranium adsorption material: The method for quaternizing the acid-grafted elastic gel spheres is as follows: the phosphate-grafted elastic gel spheres obtained in step two are mixed with methanol and solid sodium hydroxide. After the phosphate-grafted elastic gel spheres swell, iodomethane is added. Then, the mixture is placed in a constant temperature shaker and shaken at room temperature. After the reaction is completed, the gel spheres are soaked in deionized water. After the reaction is completed, quaternized acid-grafted elastic gel spheres are obtained, which are phosphate-containing sodium alginate-gelatin composite porous antibacterial hydrogel spheres uranium adsorption materials. The mass ratio of sodium alginate to methanol is 0.4-0.6 g: 20-40 mL; The mass ratio of sodium alginate to solid sodium hydroxide is 0.4-0.6:0.15-0.3; The mass ratio of sodium alginate to the volume ratio of iodomethane is 0.4-0.6 g : 5-7 mL.

3. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The crosslinking agent solution I mentioned in step one is a calcium chloride solution with a mass fraction of 2-4%; the crosslinking time in the crosslinking agent solution I is 1-3 hours.

4. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The crosslinking agent solution II mentioned in step one is a glutaraldehyde solution with a mass fraction of 1-4%; the crosslinking molding time of the crosslinking agent solution II is 7-9 hours.

5. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The mechanical stirring speed in step one is 500-700 r·min. -1 The time is 20-30 minutes.

6. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The temperature of the deionized water used in the preparation of the gelatin aqueous solution in step one is 50-60℃.

7. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The concentration of hydrochloric acid in step two is 0.1-0.2 mol / L, and the hydrochloric acid washing time is 20-30 min. After the hydrochloric acid washing is completed, wash with deionized water 3 times, and the washing time of deionized water each time is 10-15 min.

8. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The water bath reaction in step two is carried out at a temperature of 50-70℃ for 5-7 hours.

9. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The time for room temperature oscillation in the constant temperature shaker described in step three is 10-14 hours.

10. The method for preparing the uranium adsorbent material of sodium alginate-gelatin composite porous antibacterial hydrogel spheres containing phosphate groups according to claim 2, characterized in that: The gel balls described in step three are soaked in deionized water for 2-4 hours, with the deionized water being changed every 1-2 hours during this period.

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