Adsorbing material and method for directly extracting strontium from high-level liquid waste

Abstract

This invention provides an adsorbent material and a method for directly extracting strontium from high-level radioactive waste. The adsorbent material is vanadium or bismuth-doped modified polyantimony acid in powder form. The vanadium or bismuth-doped modified polyantimony acid adsorbent material is added to the strontium-containing high-level radioactive waste at a specific solid-liquid ratio, and the mixture is shaken in a constant-temperature water bath for a period of time to separate the adsorbent material from the solution. The adsorbent material provided by this invention can remain stable in high-concentration HNO3 solutions and exhibits good adhesion to strontium. 2+ It has a high removal efficiency, and its low surface potential and high stability are also beneficial for the removal of Sr in radioactive waste liquid. 2+ Adsorption.

Description

Technical Field

[0001] This invention belongs to the field of radioactive element extraction technology, specifically relating to an adsorption material and a method for directly extracting strontium from high-level radioactive waste liquid. Background Technology

[0002] Because nuclear energy does not produce greenhouse gases while generating electricity on a large scale, it is expected to continue its large-scale development in the coming decades due to stable energy demand and environmental protection pressures. Spent fuel reprocessing is crucial for the safety and sustainable development of nuclear energy. Currently, the PUREX process is a typical water-based reprocessing technology widely used in reprocessing plants worldwide. The PUREX process employs solvent extraction, based on the significant differences in the extraction capabilities of the extractant TBP for uranium, thorium, neptunium, plutonium, and fragmented elements in different oxidation states, thus purifying and separating these elements. The high-level radioactive waste generated in the PUREX process contains residual U and Pu (0.25%–0.50%), minor actinides Np, Am, and Cm, as well as long-lived fission products Sr and Cs, and contains over 95% of the radioactivity of spent fuel. It is a highly radioactive, toxic, high-heat-release, and highly acidic waste liquid. 90 Sr has a high fission yield ( 235 U nuclear fuel accounts for 5.73% and has a long half-life (T). 1 / 2 =28.8 years), highly chemically and biologically toxic, causing serious harm to ecosystems and humans. Furthermore, 90 Sr is osteotoxic and radioactive, readily accumulating in the bones of humans and animals, continuously releasing high-energy beta rays, which may lead to bone cancer. Typically... 90 Sr decays with the release of heat, which is one of the adverse factors affecting the vitrification of high-level radioactive waste liquids. Removing Sr from high-level radioactive waste liquids... 90 Sr offers several advantages for the final disposal of spent fuel: First, it eliminates most of the heat load and radiation, significantly reducing waste volume and saving storage capacity; second, it shortens the storage time for underground disposal of high-level radioactive waste. Furthermore, 90 Sr can decay into 90 Y, selectively separated from high-level radioactive waste liquid 90 Sr preparation 90 Sr- 90 Gamma generators can play an important role in applications of radiation medicine. Meanwhile, 90 Sr can be used as a raw material for isotope batteries and can be separated and extracted from high-level radioactive waste liquid. 90 Sr is a practical and feasible approach for my country to conduct research and production of Sr-90 fuel cells, which is of great significance to the development of my country's national defense and aerospace industry. Due to the complex composition and radioactivity of liquid radioactive waste, separation is necessary.90 Materials containing Sr should possess good adsorption selectivity, high acidity, and radiation resistance.

[0003] Currently, most high-level radioactive waste liquids are acidic. 90 Sr with Sr 2+ Strontium exists in solution in the form of organic compounds. Due to the complex composition of high-level radioactive waste and the fact that some elements share properties with strontium, the selective removal of strontium from such waste is quite challenging. Extensive research has been conducted both domestically and internationally to address this issue, employing methods primarily including precipitation, ion exchange, solvent extraction, chromatography, and membrane separation. While solvent extraction is a relatively mature method, it also suffers from drawbacks such as long operating procedures, the use of large quantities of organic solvents, the generation of significant waste, and the high cost, difficult synthesis, and high toxicity of some extractants, limiting its large-scale application. Adsorption methods have attracted widespread attention due to their short operating procedures, ease of operation, high selectivity, and strong adaptability. Organic ion exchange resins possess good mechanical properties, strong regeneration capabilities, and are relatively easy to operate, but their high-temperature and radiation resistance are poor, resulting in low adsorption capacity in strongly acidic solutions and a tendency to form secondary waste. Most inorganic adsorbents, while resistant to high temperatures and radiation, exhibit poor acid resistance, long adsorption equilibrium times, and low adsorption capacity. There are existing studies on the adsorption performance of polyantimony acid on strontium, but existing polyantimony acid materials do not effectively adsorb strontium onto strontium. 2+ The adsorption kinetics are slow, and the adsorption capacity is small. Currently, there is no method that fully meets the requirements for efficient removal of Sr from radioactive waste liquid under high acid and strong irradiation conditions. 2+ Adsorbent materials. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing an improved polyantimony acid adsorbent and a method for directly extracting strontium from high-level radioactive waste liquid. This material can remain stable in high-concentration HNO3 solutions and is effective against Sr. 2+ It has a highly efficient removal capability.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] An adsorbent material is a vanadium or bismuth-doped modified polyantimonic acid in powder form, wherein the molar ratio of elemental vanadium or bismuth to antimony is 0.1:1 to 1:1.

[0007] The present invention further provides a method for directly extracting strontium from high-level radioactive waste liquid using the above-mentioned adsorption material. The method involves adding vanadium or bismuth-doped modified polyantimonic acid adsorption material to the strontium-containing high-level radioactive waste liquid at a certain solid-liquid ratio, shaking it in a constant-temperature water bath for a period of time, and then separating the adsorption material from the solution.

[0008] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, vanadium-doped modified polyantimonic acid adsorbent material is preferred.

[0009] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, the solid-liquid ratio is 1:20 to 1:500.

[0010] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, the temperature of the constant temperature water bath is 25–55°C.

[0011] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, the adsorption time is 0.1 to 24 hours.

[0012] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, the nitric acid concentration of the high-level radioactive waste liquid is 0.1–4 mol / L.

[0013] Furthermore, in the method for directly extracting strontium from high-level radioactive waste liquid as described above, the adsorbent material is separated from the solution by filtration, and the concentration of strontium ions in the solution is determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0014] The beneficial effects of this invention are as follows: The polyantimony doped with bismuth or vanadium does not alter the original pyrochlore structure, and the channels in the (1 1 1) direction of the structure have exchangeable H... + It can be used to react with Sr in solution. 2+ This allows for the exchange of substances. Furthermore, the low surface potential and high stability of this material are also beneficial for the treatment of Sr in radioactive waste. 2+ The adsorption of vanadium-doped polyantimony acid on Sr at room temperature in a 3.0 mol / L nitric acid solution. 2+ The removal rate can reach up to 91.8%, with an allocation coefficient K. d It is 897.2 mL / g. Attached Figure Description

[0015] Figure 1 Polyantimonic acid with different bismuth doping molar ratios was used to treat Sr in 3 mol / L nitric acid. 2+ The amount of adsorption;

[0016] Figure 2 Polyantimonic acid with different vanadium doping molar ratios was used to treat Sr in 3 mol / L nitric acid. 2+ The amount of adsorption;

[0017] Figure 3 The reaction of undoped polyantimonic acid with bismuth- or vanadium-doped polyantimonic acid in 3 mol / L nitric acid with Sr 2+ Comparison of adsorption amounts;

[0018] Figure 4 The effect of bismuth-doped polyantimonic acid (0.1 molar ratio) on Sr in nitric acid solutions of different concentrations. 2+The amount of adsorption;

[0019] Figure 5 The effect of vanadium-doped polyantimonic acid (0.5 molar ratio) on Sr in nitric acid solutions of different concentrations. 2+ The amount of adsorption;

[0020] Figure 6 The reaction of Sr in a simulated high-level radioactive waste liquid with vanadium doping molar ratio of 0.5 using polyantimonic acid with a nitric acid concentration of 3 mol / L. 2+ The adsorption partition coefficient;

[0021] Figure 7 The reaction of bismuth-doped polyantimonic acid (0.1 molar ratio) with Sr in simulated high-level radioactive waste liquid with a nitric acid concentration of 3 mol / L. 2+ The adsorption partition coefficient. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] This invention provides an adsorbent material, which is vanadium or bismuth-doped modified polyantimonic acid in powder form, wherein the molar ratio of elemental vanadium or bismuth to antimony is 0.1:1 to 1:1.

[0024] Figure 1 The effects of different bismuth doping molar ratios (Bi / Sb = 0.1, Bi / Sb = 0.5, Bi / Sb = 1) on Sr in 3 mol / L nitric acid were investigated. 2+ A schematic diagram of the adsorption capacity.

[0025] Figure 2 The effects of different vanadium doping molar ratios (V / Sb = 0.1, V / Sb = 0.5, V / Sb = 1) on Sr in 3 mol / L nitric acid were investigated. 2+ A schematic diagram of the adsorption capacity.

[0026] Figure 3 The reaction of undoped polyantimonic acid with bismuth- or vanadium-doped polyantimonic acid in 3 mol / L nitric acid with Sr 2+ A comparison chart of adsorption amounts.

[0027] Among them, the adsorption amount q, the removal rate RE, and the partition coefficient K d The calculation formula is as follows:

[0028]

[0029]

[0030]

[0031] In the formula:

[0032] C0 represents the initial Sr in the aqueous phase. 2+ The concentration, mg / L;

[0033] C e For Sr in the aqueous phase after adsorption equilibrium 2+ The concentration, mg / L;

[0034] V is the volume of the solution, in L;

[0035] m is the mass of the adsorbent, in grams.

[0036] from Figure 1 , Figure 2 , Figure 3 As can be seen, vanadium or bismuth-doped polyantimony acid exhibits better performance on Sr compared to undoped polyantimony acid. 2+ Vanadium-doped polyantimonic acid has a stronger adsorption capacity, and its adsorption performance is better than that of bismuth-doped polyantimonic acid. Therefore, vanadium-doped polyantimonic acid is the preferred embodiment.

[0037] As a specific implementation method, the preparation method of the above-mentioned vanadium or bismuth-doped modified polyantimonic acid adsorbent material is as follows:

[0038] According to a certain doping ratio, bismuth trichloride or ammonium metavanadate is mixed with antimony trichloride in a round-bottom flask containing a certain volume of anhydrous ethanol, and then the round-bottom flask is placed in a constant temperature magnetic stirring water bath and thoroughly stirred and mixed.

[0039] After the raw materials are fully dissolved and mixed, a certain volume of 30% hydrogen peroxide solution is added to the round-bottom flask. After stirring and mixing thoroughly, the water bath is heated to 90°C and reacted for 3-5 hours. Then, the mixture is reacted at 60°C for a period of time (e.g., 12-24 hours) and filtered. The filtered product is dried in an oven to obtain vanadium or bismuth-doped modified polyantimonic acid powder.

[0040] The aforementioned vanadium or bismuth-doped modified polyantimonic acid adsorbent can be directly used to extract strontium ions from high-level radioactive waste liquid. The specific method is as follows: The vanadium or bismuth-doped modified polyantimonic acid adsorbent is added to a strontium-containing high-level radioactive waste liquid (nitric acid concentration 0.1–4 mol / L) at a certain solid-liquid ratio (1:20–1:500). The mixture is then shaken in a constant-temperature water bath for a period of time (25–55℃) for 0.1–24 hours. The adsorbent is then separated from the solution by filtration. After separation, the concentration of strontium ions in the solution is determined using inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0041] The extraction method of strontium ions from simulated feed solutions is described below through some specific experimental examples.

[0042] Specific experimental example 1:

[0043] Add 0.05 g of Bi-doped polyantimony BiSb (Bi / Sb = 0.1) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 24 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 56.5%, K d It is 129.8 mL / g.

[0044] Specific experimental example 2:

[0045] Add 0.05 g of Bi-doped polyantimony BiSb (Bi / Sb = 0.1) to a vial, then add Sr containing 0.1 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 8 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 97.5%, K d It is 3816.1 mL / g.

[0046] Specific experimental example 3:

[0047] Add 0.05 g of Bi-doped polyantimony BiSb (Bi / Sb = 0.1) to a vial, then add Sr containing 0.1 mol / L nitric acid. 2+ Five mL of a simulated feed solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 16 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 99.5%, K d The value was 19328.2 mL / g.

[0048] Specific experimental example 4:

[0049] Add 0.05 g of Bi-doped polyantimony BiSb (Bi / Sb = 0.1) to a vial, then add Sr containing 0.1 mol / L nitric acid.2+ Five mL of a simulated feed solution with a concentration of 500 mg / L (solid-liquid ratio 1:100) was placed in a 45℃ constant temperature water bath shaker and shaken for 16 hours. After shaking, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 98.8%, K d It is 8279.9 mL / g.

[0050] Figure 4 This reflects the effect of polyantimonic acid with a bismuth doping molar ratio of 0.1 on Sr in nitric acid solutions of different concentrations. 2+ The amount of adsorption.

[0051] Figure 7 This reflects the effect of bismuth-doped polyantimonic acid (0.1 molar ratio) on Sr in a simulated high-level radioactive waste solution with a nitric acid concentration of 3 mol / L in the presence of interfering ions. 2+ The adsorption partition coefficient.

[0052] Specific experimental example 5:

[0053] Add 0.05 g of V-doped polyantimonic acid (VSb) (V / Sb = 0.5) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 8 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 94.6%, K d It is 1746.1 mL / g.

[0054] Specific Experiment Example 6:

[0055] Add 0.05 g of V-doped polyantimonic acid (VSb) (V / Sb = 0.5) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 24 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 99.6%, K d It is 23832.9 mL / g.

[0056] Specific experimental example 7:

[0057] Add 0.05 g of V-doped polyantimonic acid (VSb) (V / Sb = 0.1) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 24 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 92.9%, K d It is 1311.5 mL / g.

[0058] Specific experimental example 8:

[0059] Add 0.05 g of V-doped polyantimonic acid (VSb) (V / Sb = 0.5) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ 5 mL of a simulated feed solution with a concentration of 500 mg / L (solid-liquid ratio 1:100) was placed in a 55℃ constant temperature water bath shaker and shaken. After shaking for 24 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 77.6%, K d It is 346.4 mL / g.

[0060] Specific experimental example 9:

[0061] Add 0.05 g of V-doped polyantimonic acid (VSb) (V / Sb = 1) to a vial, then add Sr containing 3.0 mol / L nitric acid. 2+ Five mL of a simulated solution with a concentration of 100 mg / L (solid-liquid ratio 1:100) was placed in a 25°C water bath and shaken. After shaking for 24 hours, the liquid in the vial was transferred to a centrifuge tube and centrifuged. The supernatant was collected for analysis. The ion concentrations before and after adsorption were measured using inductively coupled plasma atomic emission spectrometry (ICP). The Sr concentration was calculated based on the measurement results. 2+ The removal rate was 52.6%, K d It is 111.0 mL / g.

[0062] Figure 5 This reflects the effect of polyantimonic acid with a vanadium doping molar ratio of 0.5 on Sr in nitric acid solutions of different concentrations. 2+ The amount of adsorption.

[0063] Figure 6This reflects the effect of polyantimonylic acid with a vanadium doping molar ratio of 0.5 on Sr in a simulated high-level radioactive waste liquid with a nitric acid concentration of 3 mol / L. 2+ The adsorption partition coefficient.

[0064] Comparative Example 1:

[0065] The adsorbent used in Specific Example 1 was changed to undoped polyantimony acid (PAA), while all other experimental conditions remained the same as in Specific Example 1. Based on the measurement results, Sr can be calculated. 2+ The removal rate was 42.5%, K d It is 73.9 mL / g.

[0066] Comparative Example 2: (Objective: To compare with specific experimental examples 1 and 5)

[0067] The adsorbent used in specific experimental examples 1 and 5 was changed to undoped polyantimony acid (PAA), while all other experimental conditions remained the same as in specific experimental examples 1 and 5. Based on the measurement results, Sr can be calculated. 2+ The removal rate was 42.5%, K d It is 73.9 mL / g.

[0068] Comparative Example 3: (Objective: To compare with specific experimental examples 1 and 5)

[0069] The adsorbent used in specific experimental examples 1 and 5 was changed to Co-doped polyantimony acid (Co / Sb = 0.1), while all other experimental conditions remained the same as in specific experimental examples 1 and 5. Based on the measurement results, Sr can be calculated. 2+ The removal rate was 23.3%, K d It is 30.4 mL / g.

[0070] Comparative Example 4: (Objective: To compare with specific experimental examples 1 and 5)

[0071] The adsorbent used in specific experimental examples 1 and 5 was changed to Cu-doped polyantimony acid (Cu / Sb = 0.1), while all other experimental conditions remained the same as in specific experimental examples 1 and 5. Based on the measurement results, Sr can be calculated. 2+ The removal rate was 16.7%, K d It is 20.0 mL / g.

[0072] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. Thus, the invention also intends to include such variations and adaptations if they fall within the scope of the claims and their equivalents.

[0073] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of protection of the present invention should be defined by the claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A method for directly extracting strontium from high-level liquid waste, characterized by, Vanadium or bismuth-doped modified polyantimonic acid is used as the adsorbent material in powder form. The vanadium or bismuth-doped modified polyantimonic acid adsorbent material is added to a high-level radioactive waste liquid containing strontium at a certain solid-liquid ratio. The nitric acid concentration of the high-level radioactive waste liquid is 0.1-4 mol / L. The mixture is shaken in a constant-temperature water bath for a period of time to separate the adsorbent material from the solution. The molar ratio of vanadium to antimony in the vanadium-doped modified polyantimonic acid adsorbent material is 0.1:1 to 1:

1. The molar ratio of bismuth to antimony in the bismuth-doped modified polyantimonic acid adsorbent material is 0.1:

1.

2. The method for directly extracting strontium from high-level radioactive waste liquid as described in claim 1, characterized in that, The solid-liquid ratio is 1:20 to 1:

500.

3. The method for directly extracting strontium from high-level radioactive waste liquid as described in claim 1, characterized in that, The temperature of the constant temperature water bath is 25-55℃.

4. The method for directly extracting strontium from high-level radioactive waste liquid as described in claim 1, characterized in that, The adsorption time is 0.1–24 h.

5. The method for directly extracting strontium from high-level radioactive waste liquid as described in claim 1, characterized in that, The adsorbent material was separated from the solution by filtration, and the concentration of strontium ions in the solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

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