Preparation method of bismuth silicate adsorption material and application of bismuth silicate adsorption material in methyl iodine adsorption

Abstract

The application discloses a preparation method of a bismuth silicate adsorption material and application of the bismuth silicate adsorption material in methyl iodide adsorption, and comprises the following steps: dissolving Bi(NO3)3.5H2O in ethylene glycol, stirring until completely dissolved to obtain solution A; dissolving Na2SiO3.9H2O in deionized water, stirring until completely dissolved to obtain solution B; adding the solution B into the solution A drop by drop, continuously stirring, adjusting pH to obtain a reaction solution; transferring the reaction solution into a hydrothermal reaction kettle, heating and keeping warm, naturally cooling to room temperature, and then filtering, washing and drying to obtain the bismuth silicate adsorption material, namely Bi2O2SiO3. The prepared bismuth silicate adsorption material Bi2O2SiO3 has excellent methyl iodide adsorption performance, the adsorption amount of the bismuth silicate adsorption material to methyl iodide reaches 1426 mg / g, and the bismuth silicate adsorption material can form stable BiI3 after adsorbing CH3I, so that secondary pollution is effectively avoided; in addition, the preparation method is simple, the production cost is low, and the bismuth silicate adsorption material is easy to mass-produce.

Description

Technical Field

[0001] This invention belongs to the field of radioactive waste treatment technology. More specifically, this invention relates to a method for preparing bismuth silicate adsorbent material and its application in methyl iodine adsorption. Background Technology

[0002] Nuclear power plant operation and spent fuel reprocessing generate significant amounts of radioactive waste gas. Besides molecular iodine, nitric acid vapor, NO2, and N2O5, another radioactive gas (methyl iodine, CH3I) is produced. Due to its extremely long half-life, high environmental mobility, and biotoxicity, it has received widespread attention in nuclear emergency response and radioactive waste gas management. Therefore, how to economically and effectively treat radioactive CH3I gas is crucial for the environment and human health, as well as the future development and safe production of nuclear energy. However, due to the weak intermolecular forces, effectively capturing radioactive CH3I is extremely challenging.

[0003] Compared to research on radioactive molecular iodine (I2), research on the treatment of radioactive organic iodine (CH3I) is relatively limited. Solid-phase adsorption is considered one of the effective methods for treating gaseous iodine. Currently available adsorbents, including impregnated activated carbon, Ag ion-exchange zeolites, silver-containing alumina, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), mostly suffer from low adsorption capacity, high cost, and a tendency to cause secondary pollution. Therefore, developing novel iodine adsorbents with low cost, high adsorption capacity, and stable adsorption products is of great significance for the treatment of radioactive iodine gas and the healthy development of nuclear energy. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these objectives and other advantages of the present invention, a method for preparing a bismuth silicate adsorbent material is provided, comprising the following steps:

[0006] Step 1: Dissolve Bi(NO3)3·5H2O in ethylene glycol and stir until completely dissolved to obtain solution A; dissolve Na2SiO3·9H2O in deionized water and stir until completely dissolved to obtain solution B;

[0007] Step 2: Add solution B dropwise to solution A, stir continuously, adjust the pH, and obtain the reaction solution;

[0008] Step 3: Transfer the reaction solution to a hydrothermal reactor, heat and keep warm, and let it cool naturally to room temperature. After filtration, washing and drying, bismuth silicate adsorbent material, namely Bi2O2SiO3, is obtained.

[0009] Preferably, in step one, the molar volume ratio of Bi(NO3)3·5H2O to ethylene glycol is 4-8 mmol: 30-50 mL.

[0010] Preferably, in step one, the molar volume ratio of Na2SiO3·9H2O to deionized water is 2–5 mmol: 30–50 mL.

[0011] Preferably, in step two, the molar ratio of Bi(NO3)3·5H2O to Na2SiO3·9H2O is 4-8:2-5.

[0012] Preferably, in step two, stirring is continued for 20 to 40 minutes; the pH is adjusted to 11 to 13 using NaOH solution.

[0013] Preferably, the concentration of the NaOH solution is 1–3 mol / L.

[0014] Preferably, in step three, the temperature is raised to 150–250°C and held for 8–12 hours.

[0015] Preferably, in step three, the washing process involves washing with anhydrous ethanol and deionized water 2 to 5 times in sequence.

[0016] Preferably, in step three, the drying temperature is 60–100°C.

[0017] Preferably, steps one and two are replaced as follows: Step one: Dissolve Bi(NO3)3·5H2O in ethylene glycol and stir until completely dissolved to obtain solution A; dissolve Na2SiO3·9H2O in deionized water and stir until completely dissolved to obtain solution B; dissolve polyethylene glycol 400 and polyvinylpyrrolidone in deionized water and stir until completely dissolved to obtain solution C; Step two: Add solution C dropwise to solution A and stir for 10-20 min to obtain solution D; add solution B dropwise to solution D, continue stirring, adjust the pH, and subject the resulting mixture to ultrasonic-magnetic field coupling treatment to obtain the reaction solution.

[0018] Preferably, in solution C, the molar volume ratio of polyethylene glycol 400, polyvinylpyrrolidone, and deionized water is 1–3 mmol: 0.3–1 mmol: 30–50 mL.

[0019] Preferably, the specific method of the ultrasonic-magnetic field coupling treatment is as follows: the obtained mixture is placed in an ultrasonic-magnetic field coupling environment for 10 to 30 minutes, the ultrasonic power is 200 to 400 W, the ultrasonic frequency is 35 to 50 kHz, the magnetic field is a constant magnetic field, and the magnetic field strength is 100 to 300 mT.

[0020] Application of a bismuth silicate adsorbent prepared by the method described above in the adsorption of methyl iodine.

[0021] The present invention has at least the following beneficial effects: Using Bi(NO3)3·5H2O as the bismuth source, Na2SiO3·9H2O as the silicon source, and ethylene glycol as an additive, the present invention employs a simple and efficient hydrothermal method to synthesize bismuth silicate adsorbent material Bi2O2SiO3, which exhibits excellent methyl iodine adsorption performance, achieving an adsorption capacity of 1426 mg / g, superior to existing inorganic adsorbent materials. Furthermore, after adsorbing CH3I, it can form stable BiI3, effectively avoiding secondary pollution. In addition, the preparation method of the present invention is simple, has low production costs, and is easy to achieve large-scale preparation of the material.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0023] Figure 1 The XRD pattern of Bi2O2SiO3 prepared in Example 1 of this invention;

[0024] Figure 2 The XRD pattern of Bi2O2SiO3 after adsorption of methyl iodine prepared in Example 1 of this invention;

[0025] Figure 3 This is a scanning electron microscope image of Bi2O2SiO3 prepared in Example 1 of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0027] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0028] Example 1

[0029] A method for preparing a bismuth silicate adsorbent material includes the following steps:

[0030] Step 1: Dissolve 6 mmol Bi(NO3)3·5H2O in 40 mL of ethylene glycol and stir until completely dissolved to obtain solution A; dissolve 3 mmol Na2SiO3·9H2O in 40 mL of deionized water and stir until completely dissolved to obtain solution B.

[0031] Step 2: Add solution B dropwise to solution A, stir continuously for 30 minutes, and adjust the pH to 12 using 2 mol / L NaOH solution to obtain the reaction solution;

[0032] Step 3: Transfer the reaction solution to a hydrothermal reactor and place it in an oven to heat to 200°C. After holding at this temperature for 10 hours, allow it to cool naturally to room temperature. After filtration, wash the solution four times with anhydrous ethanol and deionized water, and dry it at 70°C to obtain the bismuth silicate adsorbent material, namely Bi2O2SiO3.

[0033] The scanning electron microscope image of Bi2O2SiO3 prepared in this embodiment is shown below. Figure 3 As shown.

[0034] Example 2

[0035] A method for preparing a bismuth silicate adsorbent material includes the following steps:

[0036] Step 1: Dissolve 6 mmol Bi(NO3)3·5H2O in 40 mL of ethylene glycol and stir until completely dissolved to obtain solution A; dissolve 3 mmol Na2SiO3·9H2O in 40 mL of deionized water and stir until completely dissolved to obtain solution B; dissolve 2 mmol polyethylene glycol 400 and 0.5 mmol polyvinylpyrrolidone in 40 mL of deionized water and stir until completely dissolved to obtain solution C;

[0037] Step 2: Add solution C dropwise to solution A and stir for 10 min to obtain solution D; add solution B dropwise to solution D and stir continuously for 30 min. Adjust the pH to 12 using 2 mol / L NaOH solution, and then subject the resulting mixture to ultrasonic-magnetic field coupling treatment to obtain the reaction solution. The specific method of ultrasonic-magnetic field coupling treatment is as follows: place the obtained mixture in an ultrasonic-magnetic field coupling environment for 20 min, with an ultrasonic power of 300 W, an ultrasonic frequency of 40 kHz, a constant magnetic field, and a magnetic field strength of 200 mT.

[0038] Step 3: Transfer the reaction solution to a hydrothermal reactor and place it in an oven to heat to 200°C. After holding at this temperature for 10 hours, allow it to cool naturally to room temperature. After filtration, wash the solution four times with anhydrous ethanol and deionized water, and dry it at 70°C to obtain the bismuth silicate adsorbent material, namely Bi2O2SiO3.

[0039] In this embodiment, the mixture is subjected to ultrasonic-magnetic field coupling treatment, and polyethylene glycol 400 and polyvinylpyrrolidone are used as active additives. Under the synergistic effect of ultrasonic waves and magnetic fields, the uniformity and solubility of the substances in the mixture can be promoted, and a large number of active groups can be generated in the mixture, which can enhance the reactivity, make the subsequent reaction more complete, and make the product more stable, thereby further improving its adsorption capacity for methyl iodine.

[0040] Example 3

[0041] A method for preparing a bismuth silicate adsorbent material includes the following steps:

[0042] Step 1: Dissolve 6 mmol Bi(NO3)3·5H2O in 40 mL of ethylene glycol and stir until completely dissolved to obtain solution A; dissolve 3 mmol Na2SiO3·9H2O in 40 mL of deionized water and stir until completely dissolved to obtain solution B.

[0043] Step 2: Add solution B dropwise to solution A, stir continuously for 30 min, adjust the pH to 12 using 2 mol / L NaOH solution, and subject the resulting mixture to ultrasonic-magnetic field coupling treatment to obtain the reaction solution. The specific method of ultrasonic-magnetic field coupling treatment is as follows: place the obtained mixture in an ultrasonic-magnetic field coupling environment for 20 min, with an ultrasonic power of 300 W, an ultrasonic frequency of 40 kHz, a constant magnetic field, and a magnetic field strength of 200 mT.

[0044] Step 3: Transfer the reaction solution to a hydrothermal reactor and place it in an oven to heat to 200°C. After holding at this temperature for 10 hours, allow it to cool naturally to room temperature. After filtration, wash the solution four times with anhydrous ethanol and deionized water, and dry it at 70°C to obtain the bismuth silicate adsorbent material, namely Bi2O2SiO3.

[0045] Example 4

[0046] A method for preparing a bismuth silicate adsorbent material includes the following steps:

[0047] Step 1: Dissolve 6 mmol Bi(NO3)3·5H2O in 40 mL of ethylene glycol and stir until completely dissolved to obtain solution A; dissolve 3 mmol Na2SiO3·9H2O in 40 mL of deionized water and stir until completely dissolved to obtain solution B; dissolve 2 mmol polyethylene glycol 400 and 0.5 mmol polyvinylpyrrolidone in 40 mL of deionized water and stir until completely dissolved to obtain solution C;

[0048] Step 2: Add solution C dropwise to solution A and stir for 10 minutes to obtain solution D; add solution B dropwise to solution D and stir continuously for 30 minutes, then adjust the pH to 12 using 2 mol / L NaOH solution to obtain the reaction solution;

[0049] Step 3: Transfer the reaction solution to a hydrothermal reactor and place it in an oven to heat to 200°C. After holding at this temperature for 10 hours, allow it to cool naturally to room temperature. After filtration, wash the solution four times with anhydrous ethanol and deionized water, and dry it at 70°C to obtain the bismuth silicate adsorbent material, namely Bi2O2SiO3.

[0050] Methyl iodine adsorption experiment:

[0051] (1) Measure 0.6 mL of CH3I and place it in a 100 mL hydrothermal reactor;

[0052] (2) Place Bi2O2SiO3 (mass m0, g) in a crucible and put it into a hydrothermal reactor containing CH3I;

[0053] (3) The hydrothermal reactor was placed in an oven and kept at different temperatures (150℃, 200℃) for different times (16h, 6h) to test the methyl iodine adsorption performance of Bi2O2SiO3;

[0054] (4) The adsorption amount is determined by weighing method, by weighing the mass m of the material after adsorption. t The adsorption capacity Q (mg / g) is calculated using the following formula:

[0055] Q(mg / g)=(m t -m0) / m0×1000

[0056] Figure 1 The image shows the XRD pattern of the bismuth silicate adsorbent material prepared in Example 1 of this invention. The characteristic XRD diffraction peaks in the pattern are Bi2O2SiO3 phase, indicating the successful preparation of Bi2O2SiO3.

[0057] Figure 2 The image shows the XRD pattern of the bismuth silicate adsorbent material prepared in Example 1 of this invention after adsorbing methyl iodine. It can be seen that the characteristic peaks of pure Bi₂O₂SiO₃ disappear after adsorbing methyl iodine, completely transforming into the characteristic peaks of BiI₃. This indicates that the Bi₂O₂SiO₃ material underwent a chemical reaction with methyl iodine, demonstrating that the adsorption mechanism of this invention is the chemical reaction between Bi₂O₂SiO₃ and CH₃I to generate stable BiI₃.

[0058] The methyl iodine adsorption performance of the bismuth silicate adsorbent material prepared in Example 1 of this invention is shown in Table 1. It can be seen that the Bi₂O₂SiO₃ of this invention exhibits a methyl iodine adsorption capacity of 1350 mg / g at 150℃ with an equilibrium time of 16 h; and an adsorption capacity of 1370 mg / g at 200℃ with an equilibrium time of 6 h. The results indicate that a higher adsorption temperature helps to improve the adsorption rate of methyl iodine by this material. Table 2 lists the methyl iodine adsorption performance of some existing adsorbent materials. It can be seen that the methyl iodine adsorption capacity of the Bi₂O₂SiO₃ of this invention is as high as 1370 mg / g, which is far higher than that of existing inorganic adsorbent materials.

[0059] Table 1

[0060]

[0061] Table 2

[0062]

[0063] The methyl iodine adsorption performance of the bismuth silicate adsorbent materials prepared in Examples 1 to 3 was tested. All adsorption was carried out at 200℃ for 6 hours. The results are shown in Table 3. It can be seen that the adsorption capacity of Examples 2 to 3 is higher than that of Example 1, with Example 2 having the highest adsorption capacity, reaching 1426 mg / g.

[0064] Table 3

[0065]

[0066] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An application of a bismuth silicate adsorbent, characterized in that, The bismuth silicate adsorbent material is used for methyl iodine adsorption; The preparation method of the bismuth silicate adsorbent material includes the following steps: Step 1: Dissolve Bi(NO3)3·5H2O in ethylene glycol and stir until completely dissolved to obtain solution A; dissolve Na2SiO3·9H2O in deionized water and stir until completely dissolved to obtain solution B; Step 2: Add solution B dropwise to solution A, stir continuously, adjust the pH, and obtain the reaction solution; Step 3: Transfer the reaction solution to a hydrothermal reactor, heat and keep warm, and let it cool naturally to room temperature. After filtration, washing and drying, bismuth silicate adsorbent material, namely Bi2O2SiO3, is obtained.

2. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step one, the molar volume ratio of Bi(NO3)3·5H2O to ethylene glycol is 4~8 mmol: 30~50 mL.

3. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step one, the molar volume ratio of Na2SiO3·9H2O to deionized water is 2~5mmol:30~50mL.

4. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step two, stirring is continued for 20-40 minutes; the pH is adjusted to 11-13 using NaOH solution.

5. The application of the bismuth silicate adsorbent material as described in claim 4, characterized in that, The concentration of the NaOH solution is 1~3 mol / L.

6. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step three, the temperature is raised to 150-250°C and kept at that temperature for 8-12 hours.

7. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step three, the washing process involves washing with anhydrous ethanol and deionized water 2 to 5 times in sequence.

8. The application of the bismuth silicate adsorbent material as described in claim 1, characterized in that, In step three, the drying temperature is 60~100℃.

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