Manganese-based gas adsorbent material, method for preparing same, and use thereof

Abstract

The application discloses a manganese-based gas adsorption material and a preparation method and application thereof, and belongs to the technical field of solid adsorbents. The manganese-based gas adsorption material is obtained by heating and reacting a sulfur source and a manganese salt in hydroxyethyl ethylenediamine to obtain slurry, and then separating the slurry with water, filtering and drying the obtained solid powder. 2‑ I2 is reduced into I ‑ , and I ‑ reacts with the manganese ion in the manganese-based sulfide to generate iodine salt, so that adsorption of radioactive iodine is realized, efficient removal of iodine vapor can be realized under different iodine vapor concentrations (as low as 400 ppm) and in a wide temperature range (25-75 DEG C), and there is no desorption of iodine due to long-term standing; meanwhile, the manganese-based gas adsorption material can also be used for adsorption of iodomethane and CO2 gas. The preparation method of the manganese-based gas adsorption material is simple, the preparation conditions are mild, the preparation cost is low, the yield is high, and the manganese-based gas adsorption material is easy to produce on a large scale and has great potential for commercial application.

Description

Technical Field

[0001] This invention belongs to the field of solid adsorbent technology, specifically relating to a manganese-based gas adsorbent material and its preparation method, as well as the application of this material in adsorbing radioactive iodine, iodomethane and CO2 gas. Background Technology

[0002] Currently, various processes have been developed for the removal of gaseous radioactive iodine in spent fuel reprocessing, primarily solid-phase adsorption. Solid-phase adsorption mainly utilizes porous materials, leveraging their affinity for radioactive iodine to selectively remove it from the exhaust gas. It typically boasts good removal efficiency and lower operating costs, thus attracting widespread attention. In the past decade, porous materials used as iodine adsorbents have included porous organic cages, ion-exchange zeolites, silver-based zeolites, and activated carbon. However, inorganic solid adsorbents such as silver-based zeolites are costly, have poor adsorption performance, and have adverse environmental impacts. Metal-organic frameworks (MOFs) and porous organic polymers (POPs) have higher iodine adsorption capacity than zeolites due to their high surface area, but their cost is high in actual production. Furthermore, during adsorption, the complex and irregular pores in porous materials often lead to pore blockage, thus failing to achieve the expected adsorption effect and limiting their practical application in iodine capture. The traditional industrial method for activated carbon adsorbents involves impregnating activated carbon with organic amines, such as tetraethylenetriamine. Tetraethylenetriamine is the most common impregnating agent used in activated carbon adsorbents to capture radioactive iodine. Compared to other adsorbents, tetraethylenetriamine-impregnated activated carbon exhibits excellent adsorption capacity and high purification efficiency, and the iodine capture process is relatively simple. However, its adsorption capacity decreases with increasing temperature, and organic amines are prone to sublimation, leading to a significant reduction in the iodine absorption efficiency of the impregnated carbon material. Furthermore, iodine adsorption is an exothermic process, and organic amines lower the ignition point of the impregnated carbon material, exacerbating potential safety hazards. Summary of the Invention

[0003] The purpose of this invention is to provide a manganese-based gas adsorbent material that can achieve efficient adsorption of radioactive iodine, iodomethane, and CO2 gas.

[0004] The manganese-based gas adsorbent material provided by this invention is prepared by the following method:

[0005] In step 1, the sulfur source is added to hydroxyethyl ethylenediamine, heated and stirred until the sulfur source is completely dissolved, then manganese salt powder is added, mixed evenly, and the temperature is raised to 40-70°C. The resulting mixture is then pumped into a jacketed pipeline reactor by a peristaltic pump and kept warm and circulated for 2-3 hours to obtain a slurry.

[0006] Step 2: Add water to the slurry obtained in Step 1, stir thoroughly until a precipitate is formed, centrifuge to separate it, and dry the precipitate to obtain manganese-based gas adsorbent powder; the manganese-based gas adsorbent is a mixture with manganese disulfide and manganese thiosulfate as the main phases and free sulfur element exists.

[0007] In a further preferred embodiment, in step 1 above, the sulfur source is added to hydroxyethyl ethylenediamine, heated and stirred at 30-40°C until the sulfur source is completely dissolved, then manganese salt powder is added, mixed evenly, and the temperature is raised to 50-60°C. The resulting mixture is then pumped into a jacketed pipeline reactor using a peristaltic pump and kept warm and circulated for 2-3 hours to obtain a slurry.

[0008] Further preferably, in step 1 above, the sulfur source is either sublimed sulfur powder or sodium thiosulfate.

[0009] Further preferably, in step 1 above, the manganese salt is any one of manganese nitrate, manganese sulfate, and manganese carbonate.

[0010] Further preferably, in step 1 above, the ratio of the sulfur source to hydroxyethyl ethylenediamine is 1 g: 6.5-8.5 mL.

[0011] In a further preferred embodiment, in step 1 above, the molar ratio of the manganese salt to the sulfur source is 1:5 to 8.

[0012] In a further preferred embodiment, in step 2 above, the volume ratio of the slurry to water is 1:2 to 3.

[0013] The present invention also provides the application of the manganese-based gas adsorbent as an adsorbent in the adsorption of radioactive iodine, iodomethane and CO2 gas.

[0014] Compared with traditional technologies, the beneficial effects of this invention are as follows:

[0015] 1. In this invention, hydroxyethyl ethylenediamine has higher reducing power and weak acidity, which enables the sulfide to adsorb iodine vapor, iodomethane and CO2 gas more efficiently and quickly during the adsorption process, thereby improving its adsorption capacity.

[0016] 2. This invention uses a jacketed pipe reactor as the reaction device. This device has good heat and mass transfer effects. For example, with the same volume of reactants, the heat transfer efficiency is 2 to 3 times that of a batch reactor because the pipe reactor has a larger heat transfer area and better insulation. When the same reactants participate in the reaction in the pipe, because they circulate in the pipe and are propelled by an external force provided by a peristaltic pump, this not only improves the mass transfer driving force between reactants, but also increases the mass transfer area. The mass transfer rate G is proportional to both the mass transfer area F and the mass transfer driving force Δ, and G=KFΔ (K is the mass transfer coefficient). Therefore, the mass transfer efficiency is greatly improved and the reaction time is shortened.

[0017] 3. This invention utilizes S in manganese-based gas adsorption materials. 2- Restore I2 to I - Then, through the manganese ions and I - The reaction produces iodized salt, thereby achieving the adsorption of radioactive iodine vapor. It can remove iodine vapor at different iodine vapor concentrations (down to 400 ppm) and over a wide temperature range (25–75 °C), and will not cause iodine desorption due to prolonged standing.

[0018] 4. The preparation method of the manganese-based gas adsorbent material of the present invention is simple and mild, can be synthesized at a lower temperature, is more energy-efficient, has high safety performance, and has low preparation cost, high yield, and is easy to scale up production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a jacketed pipeline reactor.

[0020] Figure 2 These are XRD patterns of different metal-based gas adsorbent materials.

[0021] Figure 3 The images are scanning electron microscope (SEM) images (a), EDS layered images (b), overall elemental distribution map (c), O elemental distribution map (d), S elemental distribution map (e), and Mn elemental distribution map (f) of MnxSy.

[0022] Figure 4 The images are: scanning electron microscope (SEM) image (a), EDS layered image (b), overall elemental distribution map (c), O elemental distribution map (d), S elemental distribution map (e), and W elemental distribution map (f) of WxSy.

[0023] Figure 5 These are scanning electron microscope (SEM) images of BixSy (a), EDS layered images (b), overall elemental distribution map (c), O elemental distribution map (d), S elemental distribution map (e), and Bi elemental distribution map (f).

[0024] Figure 6 The images are: scanning electron microscope (SEM) image (a), EDS layered image (b), overall elemental distribution map (c), O elemental distribution map (d), S elemental distribution map (e), and V elemental distribution map (f).

[0025] Figure 7 These are scanning electron microscope (SEM) images of FexSy (a), EDS layered images (b), overall elemental distribution map (c), O elemental distribution map (d), S elemental distribution map (e), and Fe elemental distribution map (f).

[0026] Figure 8 These are the isothermal adsorption-desorption curves of different metal sulfides.

[0027] Figure 9 This is a diagram showing the equilibrium adsorption capacity of different metal-based gas adsorbents under low concentrations of iodine vapor.

[0028] Figure 10 This is a diagram showing the equilibrium adsorption capacity of different metal-based gas adsorbents under low concentrations of iodomethane.

[0029] Figure 11 This is a graph showing the dynamic adsorption capacity of iodine vapor by a manganese-based gas adsorbent at 75°C. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0031] Example 1

[0032] Step 1: Add 64 g (4 mol) of sulfur powder to 500 mL of hydroxyethyl ethylenediamine, heat and stir at 30°C until the sulfur powder is completely dissolved, then add 107 g (0.75 mol) of manganese sulfate monohydrate powder, mix well, raise the temperature to 60°C, and pump the resulting mixture into a jacketed pipeline reactor (e.g., Figure 1 The slurry was obtained by circulating it in a heated environment for 3 hours (as shown in the figure).

[0033] Step 2: Add 1200 mL of water to the slurry obtained in Step 1, stir thoroughly until a precipitate is formed, centrifuge to separate the precipitate, and dry the precipitate at 60℃ to obtain manganese-based gas adsorbent material powder (denoted as MnxSy).

[0034] Comparative Example 1

[0035] The manganese sulfate monohydrate powder in Example 1 was replaced with equimolar amounts of sodium metavanadate, bismuth chloride, ferric nitrate, and tungstic acid, respectively. The other steps were the same as in Example 1, and vanadium-based iodine adsorbent powder (denoted as VxSy), bismuth-based iodine adsorbent powder (denoted as BixSy), iron-based iodine adsorbent powder (denoted as FexSy), and tungsten-based iodine adsorbent powder (denoted as WxSy) were obtained respectively.

[0036] Comparative Example 2

[0037] In step 1 of Example 1, 64 g (2 mol) of sulfur powder was added to 500 mL of hydroxyethyl ethylenediamine, heated and stirred at 30°C until the sulfur powder was completely dissolved, and then 107.5 g (0.75 mol) of manganese sulfate monohydrate powder was added. After mixing evenly, the mixture was placed in a high-pressure reactor and heated to 60°C under sealed conditions, and stirred for 3 h to obtain a slurry. The other steps were the same as in Example 1 to obtain manganese-based gas adsorbent powder.

[0038] Comparative Example 3

[0039] The hydroxyethyl ethylenediamine in Example 1 was replaced with equal volumes of diethylenetriamine and oleylamine, respectively, and the other steps were the same as in Example 1, to obtain manganese-based gas adsorbent powder.

[0040] The different metal-based gas adsorbent powders obtained in Example 1 and Comparative Example 1 were subjected to SEM scanning, XRD phase analysis, and physical adsorption-desorption experiments. The results are as follows: Figures 2-8 As shown in Table 1.

[0041] Table 1

[0042]

[0043] Depend on Figure 2 It is known that manganese-based gas adsorbents are mixtures with manganese disulfide and manganese thiosulfate as the main phases and containing free elemental sulfur. Through... Figures 3-7 Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses of different metal-based gas adsorbents revealed that all materials consisted primarily of metal sulfides and contained free elemental sulfur. Figure 8 It can be seen that different metal-based gas adsorbents all have hysteresis loops.

[0044] At 75℃, powders of different metal-based gas adsorbent materials were placed in a high-concentration iodine vapor atmosphere (16000 ppm) for 60 h to test the adsorption capacity of the materials for iodine vapor. The results are as follows: Figure 9 As shown in the figure. Different metal-based gas adsorbent powders were placed in a high-concentration iodomethane (400 ppm) atmosphere at 75℃ for 24 h. The adsorption capacity of the materials for iodomethane was then tested, and the results are shown in the figure. Figure 10 As shown.

[0045] Depend on Figure 9 It can be seen that, within the same adsorption time, the manganese-based gas adsorbent material can adsorb 9.26 g / g of iodine, which is much higher than that of other metal-based gas adsorbent materials. This is because manganese has a high oxidation state and many valence changes, making redox reactions more likely to occur during iodine ion adsorption, and allowing it to react with a larger amount of iodine. Figure 10 It can be seen that different metal-based gas adsorbents all possess a certain adsorption capacity within the same adsorption time under high-concentration iodomethane conditions, with manganese-based gas adsorbents exhibiting the most significant adsorption effect, reaching an adsorption capacity of 4.26 g / g. However, by comparing the specific surface area, pore size, and pore volume of different metal-based gas adsorbents in Table 1, manganese-based gas adsorbents have the smallest pore size and pore volume, and their specific surface area is not the largest. Further consideration... Figure 8 This indicates that the adsorption effect of different metal-based gas adsorbents is not significantly related to the size of their pores, and is dominated by chemisorption.

[0046] Furthermore, at 75°C, the manganese-based gas adsorbent powder was placed under an iodine vapor concentration at a carrier gas flow rate of 200 mL / min to test the dynamic adsorption capacity of iodine vapor. The test results are as follows: Figure 11 As shown, the dynamic adsorption capacity of iodine vapor was 3.64 g / g, and the breakthrough time was 7.12 h.

[0047] The manganese-based gas adsorbent powders obtained in Example 1, Comparative Examples 2 and 3 were subjected to iodine vapor, iodomethane, and CO2 gas adsorption experiments according to the above method. The results are shown in Tables 2 and 3.

[0048] Table 2

[0049]

[0050] As shown in Table 2, the manganese-based gas adsorbent prepared in Example 1 using a jacketed tubular reactor with circulating flow exhibits greater adsorption capacity for iodine vapor, iodomethane, and CO2 gas than the manganese-based gas adsorbent prepared in Comparative Example 2 using a high-pressure reactor with stirring. This is because the circulating flow of reactants within the jacketed tubular reactor increases the reaction rate between solutes, significantly shortens the reaction time, and increases heat transfer efficiency, thus stabilizing the adsorption efficiency of the manganese-based gas adsorbent during pilot-scale and scale-up processes.

[0051] Table 3

[0052]

[0053] As shown in Table 3, compared with the manganese-based gas adsorbent prepared using diethylenetriamine and oleylamine as template agents in Comparative Example 3, the manganese-based gas adsorbent prepared using hydroxyethylethylenediamine as a template agent exhibits a higher adsorption capacity for iodine vapor. This is because hydroxyethylethylenediamine contains hydroxyl groups, which have higher reducing power and weak acidity, making it easier for the manganese-based gas adsorbent to reduce iodide ions to iodide salts during adsorption and allowing ammonium ions to be better attached to the pores of the manganese-based gas adsorbent. Furthermore, the manganese-based gas adsorbent prepared using hydroxyethylethylenediamine as a template agent in Example 1 also showed significantly higher adsorption capacities for iodomethane and CO2 gases compared to the manganese-based gas adsorbent prepared using diethylenetriamine and oleylamine as template agents in Comparative Example 3.

[0054] Example 2

[0055] In this embodiment, the sulfur powder in Example 1 was replaced with an equimolar amount of sodium thiosulfate, and the rest was the same as in step 1, to obtain manganese-based gas adsorbent powder.

[0056] Example 3

[0057] In this embodiment, manganese sulfate monohydrate in Example 1 is replaced with an equimolar amount of manganese nitrate tetrahydrate, and the rest is the same as in step 1, to obtain manganese-based gas adsorbent powder.

[0058] Example 4

[0059] In this embodiment, manganese sulfate monohydrate in Example 1 is replaced with an equimolar amount of manganese carbonate, and the rest is the same as in step 1, to obtain manganese-based gas adsorbent powder.

[0060] Example 5

[0061] In step 1 of this embodiment, 96 g (6 mol) of sulfur powder was added to 500 mL of hydroxyethyl ethylenediamine, heated and stirred at 30°C until the sulfur powder was completely dissolved, then 107 g (0.75 mol) of manganese sulfate monohydrate powder was added, mixed evenly, and the temperature was raised to 60°C. The resulting mixture was then pumped into a jacketed pipeline reactor using a peristaltic pump and kept at the temperature for 3 hours to obtain a slurry. The other steps were the same as in Example 1, resulting in manganese-based gas adsorbent powder.

[0062] Example 6

[0063] In step 1 of this embodiment, 80 g (5 mol) of sulfur powder is added to 500 mL of hydroxyethyl ethylenediamine, heated and stirred at 60°C until the sulfur powder is completely dissolved, then 107 g (0.75 mol) of manganese sulfate monohydrate powder is added, mixed evenly, and heated to 50°C. The resulting mixture is then pumped into a jacketed pipeline reactor using a peristaltic pump and kept at the temperature for 2 hours to obtain a slurry. The other steps are the same as in Example 1 to obtain manganese-based gas adsorbent powder.

[0064] The manganese-based gas adsorbent powders obtained in Examples 2-6 were tested for adsorption performance of iodine vapor, iodomethane, and CO2 gas using the methods described above. The results are shown in Table 4.

[0065] Table 4

[0066]

Claims

1. A method for preparing a manganese-based gas adsorbent material, characterized in that: The preparation method includes the following steps: In step 1, the sulfur source is added to hydroxyethyl ethylenediamine, heated and stirred until the sulfur source is completely dissolved, then manganese salt powder is added, mixed evenly, and the temperature is raised to 40-70°C. The resulting mixture is then pumped into a jacketed pipeline reactor by a peristaltic pump and kept warm and circulated for 2-3 hours to obtain a slurry. Step 2: Add water to the slurry obtained in Step 1, stir thoroughly until a precipitate is formed, centrifuge to separate it, and dry the precipitate to obtain manganese-based gas adsorbent powder; the manganese-based gas adsorbent is a mixture with manganese disulfide and manganese thiosulfate as the main phases and free sulfur element exists.

2. The method for preparing the manganese-based gas adsorbent material according to claim 1, characterized in that: In step 1, the sulfur source is added to hydroxyethyl ethylenediamine and heated and stirred at 30-40°C until the sulfur source is completely dissolved. Then, manganese salt powder is added, mixed evenly, and the temperature is raised to 50-60°C. The resulting mixture is then pumped into a jacketed pipeline reactor using a peristaltic pump and kept warm and circulated for 2-3 hours to obtain a slurry.

3. The method for preparing the manganese-based gas adsorbent material according to claim 1, characterized in that: In step 1, the sulfur source is any one of sublimed sulfur powder and sodium thiosulfate, and the manganese salt is any one of manganese nitrate, manganese sulfate, and manganese carbonate.

4. The method for preparing the manganese-based gas adsorbent material according to claim 1, characterized in that: In step 1, the ratio of the sulfur source to hydroxyethyl ethylenediamine is 1 g: 6.5–8.5 mL.

5. The method for preparing the manganese-based gas adsorbent material according to claim 1, characterized in that: In step 1, the molar ratio of the manganese salt to the sulfur source is 1:5 to 8.

6. The method for preparing the manganese-based gas adsorbent material according to claim 1, characterized in that: In step 2, the volume ratio of the slurry to water is 1:2 to 3.

7. The manganese-based gas adsorbent material obtained by the preparation method according to any one of claims 1 to 6.

8. The use of the manganese-based gas adsorbent according to claim 7 as an adsorbent in the adsorption of radioactive iodine.

9. The use of the manganese-based gas adsorbent according to claim 7 as an adsorbent in the adsorption of radioactive iodomethane.

10. The application of the manganese-based gas adsorbent material according to claim 7 as an adsorbent in the adsorption of CO2.

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