A bismuth-loaded inorganic porous material, a preparation method thereof and application thereof in adsorbing iodomethane and / or gaseous elemental iodine

Abstract

The application relates to the technical field of spent fuel reprocessing, and discloses a bismuth-loaded inorganic porous material, a preparation method thereof and application of the material in adsorbing iodomethane and / or gaseous iodine element, the preparation of the material comprises the following steps: step 1, measuring the saturated water absorption rate of an inorganic porous carrier after calcination and activation; step 2, adding a bismuth ion-containing impregnation solution to the carrier according to 0.8-2 times the saturated water absorption rate of the carrier after activation, and grinding and ultrasonicating; and step 3, drying the material obtained in step 2 and treating the material under a reducing atmosphere to obtain the bismuth-loaded inorganic porous material; the inorganic porous material is at least one of beta molecular sieve with a silicon-aluminum ratio of 50-600, ZSM-5 molecular sieve, X / Y type molecular sieve, MCM-41 molecular sieve, 5A type molecular sieve and mordenite; the application finds that the bismuth-loaded inorganic porous material can simultaneously adsorb iodomethane and gaseous iodine element, overcomes the shortcoming that bismuth cannot react with organic iodine, and has high adsorption capacity of iodomethane and iodine element, so that the bismuth-loaded inorganic porous material can be used to replace the expensive silver-based adsorbent.

Description

Technical Field

[0001] This invention relates to the field of spent fuel reprocessing technology, specifically to a bismuth-supported inorganic porous material, its preparation method, and its application in the adsorption of iodomethane and / or gaseous iodine. Background Technology

[0002] Nuclear energy, as a green, clean, economical, and efficient new energy source, has attracted worldwide attention. Radioactive gaseous iodine ( 129 I, 131 I) Due to its extremely high migration and radiotoxicity, radioactive iodine must be filtered and purified. How to economically and effectively capture radioactive iodine has become an important research problem that urgently needs to be solved in the reprocessing of spent fuel.

[0003] Solid-phase adsorption primarily utilizes porous materials and their affinity for radioactive iodine to selectively remove it from dissolved exhaust gases. It typically boasts high removal efficiency and lower operating costs, thus attracting widespread attention and representing the forefront of radioactive iodine contaminant removal. Among these, silver-based zeolite adsorbents are the most mature iodine adsorbents, but their high cost limits their further application in post-treatment systems. In recent years, bismuth-based porous materials have gained significant attention due to their high iodine adsorption capacity and low material cost, and are expected to replace the currently widely used silver-based zeolite adsorbents.

[0004] CN113996267A discloses a method for preparing a silicon-based fiber felt-bismuth-based composite material and its application in radioactive iodine adsorption. By combining silicon-based fiber felt with elemental bismuth, the loss of bismuth particles is avoided, and the mechanical properties and stability of the material are improved.

[0005] CN113231045A discloses a composite adsorbent for removing radioactive iodine, which is prepared by solvothermal synthesis using polyethersulfone as a support. The material is composed of a large number of stacked nanosheets, possessing a porous structure with micron-sized dimensions, thus improving separation efficiency.

[0006] CN113926421A discloses a bismuth-supported inorganic porous iodine adsorbent material and its large-scale preparation method. By organically combining and improving methods such as equal-volume impregnation, milling and ultrasonic vibration, the problem that bismuth element is difficult to effectively load and difficult to scale up in conventional excessive impregnation methods is effectively overcome. The material has a high iodine adsorption capacity, but no adsorption effect on iodomethane.

[0007] However, the materials in CN111939770A and CN113231045A are synthesized using a solvothermal method, which generates a large amount of waste liquid during production. Large-scale preparation also places high demands on equipment and processes. The material carrier in CN113231045A is a polymer, whose radiation resistance is inferior to that of inorganic materials. Furthermore, organic iodine, such as iodomethane, is one of the forms in which radioactive iodine exists, and the materials described in the aforementioned patents do not have applications for adsorbing it. Therefore, developing an adsorbent material that can simultaneously adsorb elemental iodine and iodomethane, possessing high adsorption capacity and excellent thermal stability, is of significant value. Summary of the Invention

[0008] To address the problem that existing iodine adsorbents are mainly used for adsorbing gaseous iodine but have poor adsorption effects on organic iodine such as iodomethane, this invention provides an application of bismuth-supported inorganic porous material in the adsorption of iodomethane and / or gaseous iodine. It has been found that this material can simultaneously adsorb iodine and iodomethane adsorbents, and has good adsorption capacity, making it a promising replacement for the silver-based adsorbents currently widely used in industry.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] The application of a bismuth-supported inorganic porous material in the adsorption of iodomethane and / or gaseous iodine, wherein the preparation of the bismuth-supported inorganic porous material includes the following steps:

[0011] Step 1: Calcine and activate the inorganic porous support, and measure the saturated water absorption rate of the activated support;

[0012] Step 2: Prepare a bismuth ion-containing impregnation solution, add the bismuth ion-containing impregnation solution to the carrier at 0.8 to 2 times the saturated water absorption rate of the activated carrier, and grind and sonicate.

[0013] Step 3: After drying the material obtained in Step 2, treat it under a reducing atmosphere to obtain bismuth-supported inorganic porous material;

[0014] The inorganic porous material is at least one of the following: β molecular sieve, ZSM-5 molecular sieve, X / Y type molecular sieve, MCM-41 molecular sieve, 5A type molecular sieve, and mordenite, with a silica-alumina ratio of 50-600.

[0015] The bismuth-supported inorganic porous material can simultaneously adsorb iodomethane and gaseous iodine.

[0016] Further research in this invention revealed that the adsorbent material prepared with all-silica β-zeolite was almost less effective than that for iodomethane adsorption, while the adsorbent material prepared with silica-containing β-zeolite with a small amount of aluminum added exhibited a very good iodomethane adsorption effect. At the same time, it can also efficiently adsorb gaseous iodine with a larger adsorption capacity, overcoming the shortcoming of conventional bismuth-supported porous iodine adsorbent materials that are difficult to adsorb iodomethane.

[0017] Meanwhile, the applicant also found in the research that the adsorbent materials prepared by the above method using porous materials such as ZSM-5 molecular sieve, X / Y type molecular sieve, MCM-41 molecular sieve, 5A type, and mordenite can also adsorb iodomethane. The adsorption effect is better when the material combines acidic site carrier and nano-sized metallic bismuth particles.

[0018] Preferably, the inorganic porous material is a β-molecular sieve with a silica-to-alumina ratio of 50-300. A higher silica-to-alumina ratio results in better adsorption of iodine, but a decrease in adsorption of iodomethane. Adsorbents prepared from inorganic porous materials within this silica-to-alumina ratio range exhibit excellent adsorption capacity for both iodomethane and iodine.

[0019] In step 1, the calcination activation temperature is 200–600°C, and the time is 1–12 hours, carried out in an air atmosphere. Preferably, in step 1, the calcination activation temperature is 300–400°C, and the time is 2–6 hours, to remove residual moisture and organic template agent from the channels.

[0020] The saturated water absorption rate refers to the volume of solution required when the activated carrier and the impregnation solution are stirred and mixed to form a fluid state.

[0021] The testing process includes: adding the impregnation solution dropwise to the activated carrier and stirring and grinding until the mixture formed by the carrier and the solution becomes fluid, then stopping the addition of the solution and recording the ratio of the volume of the added solution to the mass of the carrier.

[0022] In step 2, the impregnation solution containing bismuth ions is a solution of bismuth-soluble salt;

[0023] The bismuth-soluble salts include bismuth nitrate, bismuth acetate, bismuth chloride, and their hydrates; solvents include ethylene glycol, concentrated nitric acid, concentrated hydrochloric acid, and dimethylformamide, such as bismuth nitrate ethylene glycol solution.

[0024] The concentration of bismuth ions in the impregnation solution is 0.1–5 g / mL.

[0025] In step 2, the grinding time is 5 to 30 minutes and the ultrasonic time is 1 to 3 hours.

[0026] In step 3, the drying temperature is 60–160℃, and the drying time is 4–24 hours;

[0027] The treatment temperature is 200–400℃ under a reducing atmosphere, the treatment time is 1–24 h, and the treatment gas is hydrogen or a mixture of hydrogen and nitrogen.

[0028] The bismuth-supported inorganic porous material has an adsorption capacity of 44.9 mg / g or higher for iodomethane and an adsorption capacity of 136.5 mg / g or higher for gaseous iodine.

[0029] Preferably, the bismuth-supported inorganic porous material has an adsorption capacity of 80.5 mg / g or higher for iodomethane and an adsorption capacity of 136.5 mg / g or higher for gaseous iodine.

[0030] Preferably, the bismuth-supported inorganic porous material has an adsorption capacity of 216.5 mg / g or higher for iodomethane and an adsorption capacity of 477.7 mg / g or higher for gaseous iodine.

[0031] The bismuth loading in the bismuth-supported inorganic porous material is above 5 wt%, preferably above 10 wt%, such as above 20 wt%.

[0032] This invention also provides a method for preparing a bismuth-supported inorganic porous material that simultaneously adsorbs iodomethane and gaseous iodine, comprising the following steps:

[0033] Step 1: Calcine and activate the inorganic porous support, and measure the saturated water absorption rate of the activated support;

[0034] Step 2: Prepare a bismuth ion-containing impregnation solution, add the bismuth ion-containing impregnation solution to the carrier at 0.8 to 2 times the saturated water absorption rate of the activated carrier, and grind and sonicate.

[0035] Step 3: After drying the material obtained in Step 2, treat it under a reducing atmosphere to obtain bismuth-supported inorganic porous material;

[0036] The inorganic porous material is a β molecular sieve with a silicon-to-aluminum ratio of 50-600, preferably a β molecular sieve with a silicon-to-aluminum ratio of 50-300.

[0037] This invention also provides a bismuth-supported inorganic porous material prepared according to the described method. This material has a high bismuth loading and can simultaneously and efficiently adsorb elemental iodine and iodomethane. In a static adsorption experiment at 140℃, the material achieves adsorption capacities of 553 mg / g for gaseous elemental iodine and 294.3 mg / g for iodomethane, demonstrating a high simultaneous adsorption capacity for both gaseous elemental iodine and iodomethane. These values ​​are relatively high among existing adsorbent materials, making it a good alternative to existing adsorbents.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The adsorbent material prepared by the present invention using aluminum-based β molecular sieve with a small amount of aluminum can simultaneously adsorb elemental iodine and iodomethane, overcoming the disadvantage that bismuth does not react with organic iodine. Moreover, the adsorption capacity of iodomethane and elemental iodine is high, and it can be used to replace expensive silver-based adsorbents.

[0040] (2) The bismuth-supported porous adsorbent material containing acidic sites provided by the present invention does not require a high-pressure environment during the preparation process, does not generate a large amount of waste liquid, and is easy to prepare in large quantities. Attached Figure Description

[0041] Figure 1 The image shows a transmission electron microscope (TEM) image of the material prepared in Example 2.

[0042] Figure 2 The XRD patterns of the material prepared in Example 2 before the adsorption experiment, after adsorbing elemental iodine, and after adsorbing iodomethane are shown.

[0043] Figure 3 The bar chart shows the adsorption capacity of iodine after adsorption using β-zeolite adsorbents with different silica-to-alumina ratios as described in Example 1.

[0044] Figure 4 The bar chart shows the adsorption capacity of iodomethane after adsorption using β-zeolite adsorbents with different silica-to-alumina ratios in Example 2.

[0045] Figure 5 The bar chart shows the adsorption capacity of β-zeolite adsorbent materials with the same silicon-to-aluminum ratio as those in Example 1 and Example 10, after adsorption of gaseous iodine and iodomethane under different bismuth loadings.

[0046] Figure 6 The bar chart shows the adsorption capacity of iodine after adsorption using other molecular sieves as carriers in Example 1.

[0047] Figure 7 The bar chart shows the adsorption capacity of iodomethane after adsorption using other molecular sieves as supports in Example 2. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0049] All raw materials used in the following specific embodiments were purchased commercially. Specifically, bismuth nitrate pentahydrate, ethylene glycol, and iodine were purchased from Shanghai Maclean Biochemical Technology Co., Ltd., and hydrochloric acid and nitric acid were purchased from Sinopharm Chemical Reagent Co., Ltd., requiring no further purification before direct use. Porous carrier materials such as β-molecular sieves were purchased from Tianjin Nanhua Catalyst Co., Ltd.

[0050] Example 1

[0051] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material with a silicon-to-aluminum ratio of 50 using a β-molecular sieve includes the following steps:

[0052] Step 1, Activation of the carrier: Take 20g of β molecular sieve with a silicon-to-aluminum ratio of 50 and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0053] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0054] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-loaded porous material containing acidic sites is obtained, with a bismuth loading of 20 wt%.

[0055] Example 2

[0056] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material with a silicon-to-aluminum ratio of 80 using a β-molecular sieve includes the following steps:

[0057] Step 1, Activation of the carrier: Take 20g of β molecular sieve with a silicon-to-aluminum ratio of 80 and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0058] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0059] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0060] Example 3

[0061] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material based on a β-molecular sieve with a silicon-to-aluminum ratio of 300 includes the following steps:

[0062] Step 1, Activation of the carrier: Take 20g of β molecular sieve with a silicon-to-aluminum ratio of 300 and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0063] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0064] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0065] Example 4

[0066] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material with a silicon-to-aluminum ratio of 600 using a β-molecular sieve includes the following steps:

[0067] Step 1, Activation of the carrier: Take 20g of β molecular sieve with a silicon-to-aluminum ratio of 600 and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0068] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0069] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0070] Example 5

[0071] A method for preparing 13X molecular sieve bismuth-based porous iodine and iodomethane adsorbent materials includes the following steps:

[0072] Step 1, Carrier activation: Take 20g of 13X molecular sieve and heat it to 350℃ in air at a rate of 5℃ / min, and keep it for 4h;

[0073] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0074] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0075] Example 6

[0076] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material based on ZSM-5 molecular sieve includes the following steps:

[0077] Step 1, Activation of the carrier: Take 20g of ZSM-5 molecular sieve and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0078] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 20.55mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 1.1mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0079] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0080] Example 7

[0081] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material based on a 5A molecular sieve includes the following steps:

[0082] Step 1, Activation of the carrier: Take 20g of 5A molecular sieve and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0083] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0084] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0085] Example 8

[0086] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material from mordenite zeolite includes the following steps:

[0087] Step 1, Carrier activation: Take 20g of mordenite and heat it to 350℃ in air at a rate of 5℃ / min, and keep it for 4h;

[0088] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 20.55mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 1.1mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0089] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0090] Example 9

[0091] A method for preparing bismuth-based porous iodine and iodomethane adsorbent materials using MCM-41 molecular sieve includes the following steps:

[0092] Step 1, Activation of the carrier: Take 20g of MCM-41 molecular sieve and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0093] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 48.20mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution required for the saturated water absorption of 1g of carrier is 2.6mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0094] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0095] Example 10

[0096] A method for preparing a bismuth-based porous iodine and iodomethane adsorbent material based on a β-molecular sieve with low bismuth loading and a silicon-to-aluminum ratio of 50 includes the following steps:

[0097] Step 1, Activation of the carrier: Take 20g of β molecular sieve with a silicon-to-aluminum ratio of 50 and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it for 4h;

[0098] Step 2: Dissolve 3.16g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0099] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-loaded porous material containing acidic sites is obtained, with a bismuth loading of 5 wt%.

[0100] Comparative Example 1:

[0101] Preparation of bismuth-supported all-silica β-molecular sieve bismuth-iodine adsorbent:

[0102] Step 1, Activation of the carrier: Take 20g of all-silica β molecular sieve and heat it to 350℃ at a rate of 5℃ / min in air atmosphere, and keep it at this temperature for 4h;

[0103] Step 2: Dissolve 15g of bismuth nitrate pentahydrate in 16.85mL of ethylene glycol to prepare the required impregnation solution. Add the impregnation solution dropwise to 5g of activated carrier until it becomes fluid. At this point, the amount of impregnation solution used to saturate the water absorption of 1g of carrier is 0.9mL. Grind the fluid in a mortar for 10min and then sonicate it in an ultrasonic machine for 1h.

[0104] Step 3: After ultrasonication in Step 2, the sample is dried in an oven at 130°C for 3 hours and then ground into powder. Finally, it is placed in a tube furnace and reduced in a high-purity hydrogen stream. The temperature is increased to 320°C at 5°C / min and held for 6 hours. After natural cooling to room temperature, the bismuth-supported porous material containing acidic sites is obtained.

[0105] Application Example 1:

[0106] 0.05 g of the materials prepared in Examples 1-10 and Comparative Example 1 were placed in 200 ml glass apparatuses, maintaining an initial concentration of gaseous iodine of 1 g / L and a temperature of 140 °C. After adsorption for 3 h, the samples were re-exposed to air for 10 min to remove uncaptured iodine. Finally, the iodine adsorption capacity was calculated by weighing the change in mass of the adsorbent before and after the reaction using a balance. The calculation was performed according to the following formula:

[0107] Iodine adsorption capacity = (mass after reaction - mass before reaction) / mass before reaction.

[0108] Application Example 2:

[0109] 0.05 g of the materials prepared in Examples 1-10 and Comparative Example 1 were placed in 200 ml glass apparatuses, maintaining an initial concentration of gaseous iodomethane of 4.56 g / L and a temperature of 140 °C. After adsorption for 12 h, the samples were re-exposed to air for 10 min to remove uncaptured iodine. Finally, their iodine adsorption capacity was calculated by weighing the mass change of the adsorbent before and after the reaction using a balance. The calculation was performed according to the following formula:

[0110] Iodine adsorption capacity = (mass after reaction - mass before reaction) / mass before reaction.

[0111] Data on the adsorption of elemental iodine and iodomethane by the materials prepared in the examples and comparative examples are as follows: Figures 1-7 And Table 1 and Table 2, Figure 1 The bismuth-supported porous adsorbent material containing acidic sites prepared in Example 2 shows nano-sized black particles, which are metallic bismuth particles.

[0112] Figure 2 The XRD patterns of the bismuth-supported porous adsorbent material (denoted as Bi-BEA-80) containing acidic sites prepared in Example 2 before adsorption, after adsorption of elemental iodine, and after adsorption of iodomethane. Before adsorption, the material shows a very obvious Bi diffraction peak, indicating successful bismuth loading onto the support. After adsorption, the material shows a very obvious BiI3 diffraction peak and a weak BiOi diffraction peak, indicating that bismuth reacted with elemental iodine and iodomethane during adsorption to form a bismuth-iodine compound.

[0113] Figure 3It can be seen that the silicon-to-aluminum ratio affects the adsorption capacity of iodine. The higher the silicon-to-aluminum ratio of the support, the greater the adsorption capacity of iodine. However, this difference is not significant in materials with a high silicon-to-aluminum ratio.

[0114] Figure 4 As can be seen, compared with materials prepared from all-silica β-zeolite, bismuth-supported porous adsorbent materials containing acidic sites, by introducing aluminum atoms, have a significant effect on the adsorption of iodomethane.

[0115] Figure 5 It can be seen that the adsorption capacity of the material with high bismuth loading is significantly higher.

[0116] Figure 6 As can be seen, compared with materials prepared from β-zeolite, bismuth-supported porous adsorbent materials containing other molecular sieves as supports have a worse adsorption effect on gaseous iodine.

[0117] Figure 7 As can be seen, compared with materials prepared from all-silica β-zeolite, other carrier bismuth-supported porous adsorbent materials containing acidic sites have better adsorption effects on iodomethane.

[0118] Table 1. Adsorption capacity of iodine and iodomethane in materials prepared in Examples 1-10 and Comparative Example 1.

[0119]

[0120] Table 2. Adsorption capacities of iodine and iodomethane in materials prepared in Examples 5-9

[0121]

[0122] In summary, the bismuth-supported porous adsorbent material containing acidic sites prepared in this invention can be used to simultaneously adsorb elemental iodine and iodomethane, and can be effectively applied to the adsorption of gaseous radioactive iodine, replacing expensive silver-based adsorbents.

[0123] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Use of a bismuth-loaded inorganic porous material for adsorbing methyl iodide and gaseous iodine elemental, characterized in that, The preparation of the bismuth-loaded inorganic porous material comprises the following steps: Step 1: calcination and activation of the inorganic porous carrier, and measurement of the saturated water absorption of the carrier after activation; Step 2: preparation of a bismuth ion-containing impregnation solution, addition of the bismuth ion-containing impregnation solution to the carrier at 0.8-2 times the saturated water absorption of the carrier after activation, and grinding and ultrasonic treatment; Step 3: drying of the material obtained in Step 2 and treatment in a reducing atmosphere to obtain the bismuth-loaded inorganic porous material; The inorganic porous material is at least one of a β molecular sieve with a silica-alumina ratio of 50-300, a ZSM-5 molecular sieve, an X / Y type molecular sieve, an MCM-41 molecular sieve, a 5A molecular sieve, and a mordenite; The bismuth-loaded inorganic porous material can simultaneously adsorb iodomethane and gaseous iodine; The adsorption capacity of the bismuth-loaded inorganic porous material for iodomethane is above 44.9 mg / g, and the adsorption capacity for gaseous iodine is above 136.5 mg / g. The saturated water absorption refers to the volume of the solution required when the carrier after activation is mixed with the impregnation solution by stirring to form a fluid.

2. Use of the bismuth-loaded inorganic porous material according to claim 1 for the adsorption of methyl iodide and gaseous iodine elementary substance, characterized in that, In Step 1, the calcination and activation temperature is 200-600°C, and the time is 1-12 h, and the process is carried out in an air atmosphere.

3. The bismuth-loaded inorganic porous material according to claim 1 for use in adsorbing iodomethane and gaseous iodine, characterized in that, The saturated water absorption test process comprises: adding the impregnation solution dropwise to the carrier after activation and stirring and grinding until the mixture of the carrier and the solution forms a fluid, then stopping the addition of the solution, and recording the ratio of the volume of the added solution to the mass of the carrier.

4. Use of the bismuth-loaded inorganic porous material according to claim 1 for the adsorption of methyl iodide and gaseous iodine elementary substance, characterized in that, In Step 2, the bismuth ion-containing impregnation solution is a solution of a bismuth-soluble salt; The bismuth-soluble salt includes one of bismuth nitrate, bismuth acetate, bismuth chloride, and hydrates thereof; and the solvent includes one of ethylene glycol, concentrated nitric acid, concentrated hydrochloric acid, and dimethylformamide. And / or, the concentration of bismuth ions in the bismuth ion-containing impregnation solution is 0.1-5 g / mL.

5. Use of the bismuth-loaded inorganic porous material according to claim 1 for the adsorption of methyl iodide and gaseous iodine elemental, characterized in that, In Step 2, the grinding time is 5-30 min, and the ultrasonic treatment time is 1-3 h.

6. Use of the bismuth-loaded inorganic porous material according to claim 1 for the adsorption of methyl iodide and gaseous iodine elemental, characterized in that, In Step 3, the drying temperature is 60-160°C, and the drying time is 4-24 h; The treatment temperature in the reducing atmosphere is 200-400°C, the treatment time is 1-24 h, and the treatment gas is hydrogen or a mixture of hydrogen and nitrogen.

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