A full-silica zeolite confined thiadiazole iodine adsorption material, a preparation method and application thereof

Abstract

The application discloses a full-silicon zeolite limited thiazolium iodine adsorption material and a preparation method and application thereof. The adsorption material comprises a full-silicon zeolite carrier and thiazolium guest molecules limited in the pore, pore opening or interlamellar limited space of the full-silicon zeolite carrier. The preparation method comprises the following steps: dissolving the thiazolium guest molecules in an organic solvent to obtain an impregnation solution; adding the impregnation solution into the activated full-silicon zeolite carrier, and mixing, grinding or ultrasonic treatment to make the thiazolium guest molecules enter the limited space of the full-silicon zeolite; and drying and aging the sample to obtain the adsorption material. The thiazolium guest molecules can provide functional sites such as amino, heterocyclic nitrogen / sulfur, mercapto / sulfone tautomer structure or methyl-substituted thiazole skeleton, can occur charge transfer, polarization and N / S site related action with I2 or CH3I, and the adsorption material has high static adsorption capacity for I2 and CH3I and is suitable for iodine species trapping.

Description

Technical Field

[0001] This invention relates to the field of radioactive iodine pollution control and porous inorganic adsorption materials, specifically to an all-silica zeolite confined thiadiazole iodine adsorption material, its preparation method, and its application. Background Technology

[0002] Volatile iodine species, mainly elemental iodine and organic iodine, may be released during nuclear fuel reprocessing, nuclear facility operation, and nuclear accidents. Radioactive iodine is characterized by its high mobility, significant environmental hazards, and high risk of bioaccumulation. Therefore, developing adsorbent materials that can effectively capture iodine species is of great importance.

[0003] Porous adsorbent materials such as activated carbon, mesoporous materials, metal-organic frameworks, and zeolites have been used for iodine capture. All-silica zeolites, with their hydrophobic channels, good thermal stability, and inorganic framework stability, are excellent carriers for constructing iodine adsorbent materials. However, pure all-silica zeolites lack functional sites for strong interactions with iodine species, thus their adsorption capacity remains limited.

[0004] Thiadiazole molecules contain amino groups, heterocyclic nitrogen atoms, and sulfur atoms, which can interact with iodine species such as I2 or CH3I through charge transfer, polarization, or N / S site interactions. Introducing these molecules into the confined space of all-silica zeolites could potentially leverage both the hydrophobic confinement of the zeolite and the multi-site iodine interactions of the thiadiazole molecules, thereby enhancing iodine capture capacity. Summary of the Invention

[0005] The purpose of this invention is to provide a confined thiadiazole iodine adsorbent material in all-silica zeolite, its preparation method and application, in order to solve the problems of insufficient active sites, limited single nitrogen-containing small molecule action sites and low loading efficiency of nitrogen- and sulfur-containing heterocyclic molecules in existing all-silica zeolite materials.

[0006] 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.

[0007] To achieve the above objectives, the present invention provides a silica zeolite-confined thiadiazole iodine adsorbent material, the adsorbent material comprising a silica zeolite support and thiadiazole guest molecules confined in the channels, pores or interlayer confinement spaces of the silica zeolite support.

[0008] Preferably, the all-silica zeolite carrier is MFI structure all-silica zeolite, Silicalite-1, or all-silica zeolite nanosheets NSL-1; Preferably, the thiadiazole guest molecule is one or more of 2-amino-1,3,4-thiadiazole (hereinafter referred to as 2-ATD), 5-amino-1,2,4-thiadiazole (hereinafter referred to as 4-ATD), 5-amino-1,2,3-thiadiazole (hereinafter referred to as 5-ATD), and 2-mercapto-5-methyl-1,3,4-thiadiazole (hereinafter referred to as MMD).

[0009] Preferably, the mass fraction of the thiadiazole guest molecule in the adsorbent material is 1-60 wt%.

[0010] The present invention also provides a method for preparing the all-silica zeolite confined thiadiazole iodine adsorbent material as described above, comprising the following steps: The all-silica zeolite support is activated; thiadiazole guest molecules are dissolved in an organic solvent to obtain an impregnation solution; the impregnation solution is added to the activated all-silica zeolite support, and the thiadiazole guest molecules are mixed, ground or sonicated to allow them to enter the confined space of the all-silica zeolite; the resulting sample is dried and aged to obtain the adsorbent material.

[0011] Preferably, the organic solvent is acetonitrile, and the concentration of the thiadiazole guest molecules in the impregnation solution is 0.5-300 mg / mL.

[0012] Preferably, the mass-to-volume ratio of the thiadiazole guest molecule to the organic solvent is 100-180 mg:1 mL; and the mass ratio of the thiadiazole guest molecule to the activated all-silica zeolite carrier is 1-1.5:1.

[0013] Preferably, the activation treatment is drying at 80-180℃ for 6-24 h or calcining at 250-450℃ for 2-8 h; the drying treatment is drying at 40-120℃ for 2-24 h; and the aging treatment is treating at 70-130℃ for 6-96 h.

[0014] The present invention also provides an application of the all-silica zeolite confined thiadiazole iodine adsorbent material as described above in the capture of iodine species, characterized in that the iodine species include I2, CH3I, organic iodine, radioactive iodine isotopes and combinations thereof.

[0015] The present invention has at least the following beneficial effects: (1) The thiadiazole guest molecules contain amino groups, nitrogen atoms on the ring, sulfur atoms, methyl-substituted thiadiazole skeletons, etc., which can provide multi-site iodine interactions; (2) NSL-1 all-silica zeolite has a hydrophobic confined space, which helps to reduce the impact of water competition; (3) The acetonitrile impregnation-post-synthesis confinement method is simple to operate and can achieve a high guest loading capacity; (4) The prepared adsorbent material exhibits high static adsorption capacity for I2 and CH3I, and is suitable for iodine species capture.

[0016] 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

[0017] Figure 1 Scanning electron microscope image of 2-ATD@NSL-1 material.

[0018] Figure 2 SEM image and EDS elemental distribution map of 2-ATD@NSL-1 material after I2 adsorption.

[0019] Figure 3 SEM image and EDS elemental distribution map of 4-ATD@NSL-1 material after CH3I adsorption.

[0020] Figure 4 The XRD and FT-IR plots are for the ATD@NSL-1 material.

[0021] Figure 5 The N2 adsorption-desorption isotherm and pore size distribution diagram of ATD@NSL-1 material.

[0022] Figure 6 This is a graph showing the static adsorption performance of I2 on the ATD@NSL-1 material.

[0023] Figure 7 The static adsorption performance of ATD@NSL-1 material for CH3I is shown in the figure.

[0024] Figure 8 The image shows the XRD pattern of ATD@NSL-1 material after adsorption of I2 or CH3I.

[0025] Figure 9 Raman and FT-IR spectra of ATD@NSL-1 material after adsorption of I2 or CH3I.

[0026] Figure 10 XPS spectra of 4-ATD@NSL-1 before and after adsorption of I2 or CH3I.

[0027] Figure 11 Scanning electron microscope image of MMD@NSL-1 material.

[0028] Figure 12 SEM image and EDS elemental distribution map of MMD@NSL-1 material after I2 adsorption.

[0029] Figure 13SEM image and EDS elemental distribution map of MMD@NSL-1 material after CH3I adsorption.

[0030] Figure 14 The XRD and FT-IR plots are for the MMD@NSL-1 material.

[0031] Figure 15 The N2 adsorption-desorption isotherm and pore size distribution diagram of MMD@NSL-1 material.

[0032] Figure 16 The static adsorption performance of MMD@NSL-1 material for I2 is shown in the figure.

[0033] Figure 17 The static adsorption performance of MMD@NSL-1 material for CH3I is shown in the figure.

[0034] Figure 18 The image shows the XRD pattern of MMD@NSL-1 material after adsorption of I2 or CH3I.

[0035] Figure 19 Raman and FT-IR spectra of MMD@NSL-1 material after adsorption of I2 or CH3I.

[0036] Figure 20 XPS spectra of MMD@NSL-1 material before and after adsorption of I2 or CH3I.

[0037] Figure 21 The graph shows a comparison of the static adsorption capacity of blank NSL-1 and a representative thiadiazole confined composite material at 75℃. Detailed Implementation

[0038] 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.

[0039] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0040] In an embodiment of the present invention, the preparation method of the NSL-1 carrier is as follows: 16.7 mL of tetraethyl orthosilicate (TEOS, 98%), 5.55 mL of tetrapropylammonium hydroxide aqueous solution (TPAOH, 2.0 mol / L), and 50 mL of deionized water were mixed and stirred at 90 °C for 24 h to obtain a mixture. Subsequently, 2.73 g of ammonium fluoride (NH4F) was dissolved in 95 mL of deionized water to form an aqueous solution of approximately 28.7 mg / mL (approximately 0.78 mol / L based on NH4F), which was added to the above mixture to obtain a gel system. The mixture was stirred at 90 °C for another 24 h. The resulting gel was transferred to a high-pressure reactor and hydrothermally crystallized at 120 °C for 4 days. After crystallization, the product was filtered, washed with water, and dried, and then calcined at 550 °C for 6 h to obtain hydrophobic all-silica zeolite NSL-1. Example 1: Preparation of 4-ATD@NSL-1 adsorbent material: Weigh 100 mg of hydrophobic all-silica zeolite NSL-1, which has been calcined and activated at 350 °C for 4 h, and immediately transfer it to a desiccator after cooling. Dissolve 116.4 mg of 5-amino-1,2,4-thiadiazole in 0.9 mL of anhydrous acetonitrile to prepare 4-ATD acetonitrile impregnation solution. Add the 4-ATD acetonitrile impregnation solution dropwise to NSL-1 while grinding. After the addition is complete, continue manual grinding for 10 min and ultrasonic treatment for 30 min. Then dry under vacuum or dry nitrogen at 60 °C for 6 h and age at 90 °C for 12 h to obtain 4-ATD@NSL-1 adsorbent material.

[0041] Example 2: Following the method in Example 1, 5-amino-1,2,4-thiadiazole was replaced with 2-amino-1,3,4-thiadiazole to obtain 2-ATD@NSL-1 adsorbent material.

[0042] Example 3: Following the method in Example 1, 5-amino-1,2,4-thiadiazole was replaced with 5-amino-1,2,3-thiadiazole to obtain 5-ATD@NSL-1 adsorbent material.

[0043] Example 4: Preparation of MMD@NSL-1 adsorbent material: Weigh 100 mg of hydrophobic all-silica zeolite NSL-1, which has been calcined and activated at 350 °C for 4 h, and immediately transfer it to a desiccator after cooling. Dissolve 132.9 mg of 2-mercapto-5-methyl-1,3,4-thiadiazole in 0.9 mL of anhydrous acetonitrile to prepare MMD acetonitrile impregnation solution. Add the MMD acetonitrile impregnation solution dropwise to NSL-1 while grinding. After the addition is complete, continue manual grinding for 10 min and ultrasonic treatment for 30 min. Then dry under vacuum or dry nitrogen at 60 °C for 6 h and age at 90 °C for 12 h to obtain MMD@NSL-1 adsorbent material.

[0044] The adsorption materials prepared in Examples 1-4 were characterized by SEM, XRD, FT-IR, N2 adsorption-desorption and TGA. Figure 1 The microstructure of the ATD@NSL-1 material is shown, among which... Figure 1 (a) and Figure 1 (b) Displaying the 2-ATD@NSL-1 sample after confinement treatment; Figure 1 (c) Displaying the 4-ATD@NSL-1 sample after confinement treatment; Figure 1 (d) Shows the 5-ATD@NSL-1 sample after confinement treatment.

[0045] Figure 2 The images show the SEM images and EDS elemental distribution maps of the 2-ATD@NSL-1 material after I2 adsorption; Figure 2 (a) is a SEM image of the 2-ATD@NSL-1 material after I2 adsorption; Figure 2 (b) is a mapping diagram of the 2-ATD@NSL-1 material after I2 adsorption, showing the distribution of silicon elements; Figure 2 (c) is a mapping diagram of the 2-ATD@NSL-1 material after I2 adsorption, showing the distribution of sulfur. Figure 2 (d) is a mapping diagram of 2-ATD@NSL-1 material after I2 adsorption, showing the distribution of iodine; Figure 2 (e) is a mapping diagram of the 2-ATD@NSL-1 material after I2 adsorption, showing the distribution of nitrogen.

[0046] Figure 3 The images show the SEM images and EDS elemental distribution maps of the 4-ATD@NSL-1 material after CH3I adsorption; among them, Figure 3 (a) is a SEM image of the 4-ATD@NSL-1 material after adsorption of CH3I; Figure 3 (b) is a mapping diagram of the 4-ATD@NSL-1 material after I2 adsorption, showing the distribution of silicon elements; Figure 3(c) is a mapping diagram of the 4-ATD@NSL-1 material after I2 adsorption, showing the distribution of sulfur. Figure 3 (d) is a mapping diagram of 4-ATD@NSL-1 material after I2 adsorption, showing the distribution of iodine; Figure 3 (e) is a mapping diagram of the 4-ATD@NSL-1 material after I2 adsorption, showing the distribution of nitrogen.

[0047] Figure 4 The XRD and FT-IR plots are for the ATD@NSL-1 material. Figure 4 (a) This shows that the sample still retains the main crystal structure features of NSL-1 after confinement treatment; Figure 4 (b) Infrared characteristic absorption peaks of ATD-like guest molecules are shown. For 4-ATD@NSL-1, an infrared peak at approximately 3396 cm⁻¹ is observed. -1 Approximately 1618 cm -1 Approximately 1529 cm -1 Approximately 1461 cm -1 The characteristic peak at that location.

[0048] Figure 5 The diagram shows the N2 adsorption-desorption isotherm and pore size distribution of the ATD@NSL-1 material. Figure 5 (a) is the N2 adsorption-desorption isotherm and pore size distribution diagram of 2-ATD@NSL-1 material; Figure 5 (b) is the N2 adsorption-desorption isotherm and pore size distribution diagram of the 4-ATD@NSL-1 material; Figure 5 (c) is the N2 adsorption-desorption isotherm and pore size distribution diagram of the 5-ATD@NSL-1 material; Figure 5 The changes in specific surface area, pore volume, and pore size distribution of the material after confinement indicate that ATD-type guest molecules have entered or occupied the confinement space of NSL-1. Thermogravimetric analysis shows that the weight loss ratio of the main organic component of 4-ATD@NSL-1 is approximately 46.58%, which is higher than that of 2-ATD@NSL-1 and 5-ATD@NSL-1, indicating that 4-ATD@NSL-1 has a higher guest loading capacity under the current conditions.

[0049] I2 static adsorption test: A certain mass of ATD@NSL-1, MMD@NSL-1, or NSL-1 sample is placed in a weighing bottle or sample boat, and together with I2 crystals, placed in a sealed container, ensuring that the sample and I2 crystals do not come into direct contact. The sealed container is placed at 75°C for adsorption, and the sample is periodically removed for weighing or iodine content analysis.

[0050] Figure 6 The static adsorption performance of ATD@NSL-1 material for I2 is shown; Figure 6 (a) Static adsorption performance of 2-ATD@NSL-1 for I2 (I2-2-ATD@NSL-1 in the figure). Figure 6 (b) shows the static adsorption performance of 4-ATD@NSL-1 for I2 (I2-4-ATD@NSL-1 in the figure). Figure 6 (c) shows the static adsorption performance of 5-ATD@NSL-1 for I2 (I2-5-ATD@NSL-1 in the figure); existing experimental results show that the maximum static adsorption capacity of the preferred 2-ATD@NSL-1 sample for I2 can reach 4069.04±115 mg / g, and equilibrium is reached in about 8 h.

[0051] CH3I static adsorption test: A certain mass of ATD@NSL-1, MMD@NSL-1, or NSL-1 sample was placed in a closed adsorption system containing CH3I, and static adsorption tests were performed at 75℃. After adsorption, the adsorption capacity was calculated by mass change, iodine content analysis, or related indirect quantitative methods.

[0052] Figure 7 The static adsorption performance of ATD@NSL-1 material for CH3I is shown; Figure 7 (a) Static adsorption performance of 2-ATD@NSL-1 for CH3I (CH3I-2-ATD@NSL-1 in the figure); Figure 7 (b) shows the static adsorption performance of 4-ATD@NSL-1 on CH3I (CH3I-4-ATD@NSL-1 in the figure). Figure 7 (c) shows the static adsorption performance of 5-ATD@NSL-1 for CH3I (CH3I-5-ATD@NSL-1 in the figure); existing experimental results show that the maximum static adsorption capacity of the preferred 4-ATD@NSL-1 sample for CH3I can reach 1212±53 mg / g, and equilibrium is reached in about 16 h.

[0053] Post-adsorption structure and mechanism analysis: Figure 2 and Figure 3 The typical SEM and EDS results of ATD@NSL-1 material after adsorption of I2 and CH3I are shown, indicating that the samples still maintain a solid morphology after adsorption and the distribution of iodine can be observed.

[0054] Figure 8 The XRD patterns after adsorption of I2 or CH3I are shown. Figure 8 (a) is the XRD pattern of 2-ATD@NSL-1 after adsorption of I2 or CH3I; Figure 8 (b) is the XRD pattern of 4-ATD@NSL-1 after adsorption of I2 or CH3I; Figure 8(c) is the XRD pattern of 5-ATD@NSL-1 after adsorption of I2 or CH3I; indicating that the sample still retains the main structural features of NSL-1 after adsorption.

[0055] Figure 9 The Raman and FT-IR results were used to analyze the state of iodine species and changes in characteristic peaks of ATD molecules after adsorption; among them Figure 9 (a) is the Raman spectroscopy diagram of ATD@NSL-1 after I2 adsorption; Figure 9 (b) is the FT-IR spectrum of 5-ATD@NSL-1 after adsorption of I2 or CH3I; Figure 9 (c) is the FT-IR spectrum of 4-ATD@NSL-1 after adsorption of I2 or CH3I; Figure 9 (d) is the FT-IR spectrum of 2-ATD@NSL-1 after adsorption of I2 or CH3I; Figure 10 XPS results showed that iodine was present in the sample after adsorption, and the changes in S 2p and N 1s spectra indicated that sulfur and nitrogen sites in 4-ATD@NSL-1 were involved in I2 or CH3I adsorption; these results are consistent with the interaction between sulfur and nitrogen sites in 4-ATD@NSL-1 and I2 or CH3I. Figure 10 (a) XPS images of 4-ATD@NSL-1 before and after adsorption of I2 or CH3I; Figure 10 (b) is the S 2p spectrum of 4-ATD@NSL-1 before and after adsorption of I2 or CH3I; Figure 10 (c) is the N 1s spectrum of 4-ATD@NSL-1 before and after adsorption of I2 or CH3I; Figure 10 (d) is the I 3d spectrum of 4-ATD@NSL-1 before and after adsorption of I2 or CH3I; Figure 11 The microstructure of the MMD@NSL-1 material is shown at different magnifications.

[0056] Figure 12 The images show the SEM image and EDS elemental distribution of the MMD@NSL-1 material after I2 adsorption; Figure 12 (a) is a SEM image of MMD@NSL-1 material after I2 adsorption; Figure 12 (b) is a mapping diagram of MMD@NSL-1 material after I2 adsorption, showing the distribution of silicon elements; Figure 12 (c) is a mapping diagram of the MMD@NSL-1 material after I2 adsorption, showing the distribution of sulfur. Figure 12 (d) is a mapping diagram of MMD@NSL-1 material after I2 adsorption, showing the distribution of iodine; Figure 12(e) is a mapping diagram of the MMD@NSL-1 material after I2 adsorption, showing the distribution of nitrogen.

[0057] Figure 13 The images show the SEM image and EDS elemental distribution of the MMD@NSL-1 material after CH3I adsorption. Figure 13 (a) is a SEM image of MMD@NSL-1 material after adsorption of CH3I; Figure 13 (b) is a mapping diagram of MMD@NSL-1 material after I2 adsorption, showing the distribution of silicon elements; Figure 13 (c) is a mapping diagram of the MMD@NSL-1 material after I2 adsorption, showing the distribution of sulfur. Figure 13 (d) is a mapping diagram of MMD@NSL-1 material after I2 adsorption, showing the distribution of iodine; Figure 13 (e) is a mapping diagram of the MMD@NSL-1 material after I2 adsorption, showing the distribution of nitrogen.

[0058] Figure 12 and Figure 13 The SEM and EDS results of MMD@NSL-1 material after adsorption of I2 and CH3I are shown respectively. As can be seen from the figure, the sample still maintains the solid particle or plate-like morphology after adsorption, and the distribution of iodine in the material can be observed, indicating that iodine species are captured by MMD@NSL-1 sample and retained in the adsorbent material.

[0059] Figure 14 The XRD and FT-IR plots are for the MMD@NSL-1 material. Figure 14 (a) This shows that the sample still retains the main crystal structure features of NSL-1 after confinement treatment; Figure 14 (b) Displays the characteristic infrared absorption peaks of MMD guest molecules. MMD@NSL-1 can reach approximately 1570 cm⁻¹. -1 Vibrations in the thiadiazole ring skeletal framework and C=N / CN-related absorptions were observed nearby, at approximately 1460 cm⁻¹. -1 Absorption associated with methyl deformation vibration and ring skeleton vibration was observed nearby; approximately 608 cm⁻¹ -1 The nearby absorption peaks can be attributed to CSC stretching, CS-related vibrations, or thiadiazole ring deformation vibrations.

[0060] Figure 15 The N2 adsorption-desorption isotherm and pore size distribution diagram of MMD@NSL-1 material; Figure 15 The specific surface area, pore volume, and pore size distribution of the material changed significantly after confinement. The BET specific surface area of ​​the NSL-1 support is approximately 367.633 m². 2 / g, total pore volume is approximately 0.260 cm³. 3 / g, pore size approximately 3.822 nm; BET specific surface area of ​​the MMD@NSL-1 sample approximately 8.648 m² / g. 2 / g, total pore volume is approximately 0.023 cm³. 3 The pore size is approximately 3.407 nm, indicating that MMD has entered or occupied the confined space of NSL-1. Thermogravimetric analysis shows that the weight loss ratio of the main organic components of MMD@NSL-1 is approximately 60.67%, indicating that a high MMD loading can be obtained under the conditions of this invention.

[0061] Figure 16 The static adsorption performance of MMD@NSL-1 material for I2 was demonstrated. Current experimental results show that the maximum static adsorption capacity of the MMD@NSL-1 sample for I2 can reach 4634±131 mg / g, and adsorption equilibrium is reached in approximately 12 h. Figure 16 (a) Static adsorption diagrams of NSL-1:MMD (1:1 (MMD-1), 1:2 (MMD-2), 1:3 (MMD-3), 1:4 (MMD-4)) at different ratios; Figure 16 (b) is the adsorption kinetic diagram of thiadiazole I2 vapor confined in all-silica zeolite in Example 4.

[0062] Figure 17 The static adsorption performance of MMD@NSL-1 material for CH3I was demonstrated. Current experimental results show that the maximum static adsorption capacity of the MMD@NSL-1 sample for CH3I can reach 1154±22 mg / g, and adsorption equilibrium is reached in approximately 18 h. Figure 17 (a) Static adsorption diagrams of NSL-1:MMD (1:1 (MMD-1), 1:2 (MMD-2), 1:3 (MMD-3), 1:4 (MMD-4)) at different ratios; Figure 17 (b) is the vapor kinetics adsorption diagram of CH3I confined in all-silica zeolite in Example 4.

[0063] Figure 18 The XRD patterns after adsorption of I2 or CH3I are shown, indicating that the samples still retain the main structural features of the NSL-1 host after adsorption.

[0064] Figure 19 The Raman results were used to analyze the state of iodine species after I2 adsorption in MMD@NSL-1. They can be used to determine the charge transfer or multiiodine species signal formed after the interaction between I2 and sulfur and nitrogen sites in MMD molecules. The relevant signals are consistent with the possibility of charge transfer, polarization and formation of multiiodine species at sulfur / nitrogen sites of I2 and MMD.

[0065] Figure 19The FT-IR results were used to compare the shifts and intensities of MMD characteristic peaks before and after I2 or CH3I adsorption. Figure 19 (a) is the Raman spectroscopy diagram of MMD@NSL-1 after I2 adsorption; Figure Figure 19 (b) is the FT-IR spectrum of MMD@NSL-1 after adsorption of I2 or CH3I; Figure 20 XPS results showed the presence of iodine in the post-adsorption sample, and changes in the S 2p, N 1s, and I 3d spectra indicated that the sulfur and nitrogen sites in MMD@NSL-1 participated in I2 or CH3I adsorption. For I2 adsorption, the sulfur and nitrogen sites in the MMD molecule can undergo charge transfer, polarization, or polyiodine species stabilization with I2; for CH3I adsorption, the sulfur and nitrogen sites in the MMD molecule can participate in nucleophilic substitution, methylation, or iodide-related interactions, thereby achieving the capture of organic iodine. Figure 20 (a) XPS images of MMD@NSL-1 before and after adsorption of I2 or CH3I; Figure 20 (b) is the S 2p spectrum of MMD@NSL-1 before and after adsorption of I2 or CH3I; Figure 20 (c) is the N 1s spectrum of MMD@NSL-1 before and after adsorption of I2 or CH3I; Figure 20 (d) is the I 3d spectrum of MMD@NSL-1 before and after adsorption of I2 or CH3I; Figure 21 This is a comparison of the static adsorption capacities of blank NSL-1 and a representative thiadiazole-confined composite material at 75℃. Figure 21 (a) The adsorption capacity of NSL-1, 2-ATD@NSL-1 and MMD@NSL-1 for I2; Figure 21 (b) The adsorption capacities of NSL-1, 4-ATD@NSL-1, and MMD@NSL-1 for CH3I. To evaluate the contribution of thiadiazole guests to iodine capture performance, the static adsorption capacities of blank NSL-1 and representative confined composite materials were compared. Figure 21 As shown in (a), the apparent adsorption capacity of blank NSL-1 for I2 is approximately 516.28 mg / g, while the maximum static adsorption capacities of 2-ATD@NSL-1 and MMD@NSL-1 for I2 reach 4069.04±115 mg / g and 4634±131 mg / g, respectively. Figure 21As shown in (b), the apparent adsorption capacity of blank NSL-1 for CH3I was approximately 221.37 mg / g, while the maximum static adsorption capacities of 4-ATD@NSL-1 and MMD@NSL-1 for CH3I reached 1212±53 mg / g and 1154±22 mg / g, respectively. These results indicate that, under the existing test conditions, the introduction of thiadiazole guests containing N / S functional sites significantly improved the static adsorption capacity of the materials for both I2 and CH3I.

[0066] The above embodiments illustrate that the present invention introduces MMD or ATD-like molecules into the confinement space of NSL-1 all-silica zeolite through acetonitrile impregnation-post-synthesis confinement method. The resulting adsorbent material has both the hydrophobic framework of all-silica zeolite and the N / S multi-site interaction ability of MMD and ATD molecules, and can be used for the static adsorption and capture of I2, CH3I and radioactive iodine species.

[0067] 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. A silica zeolite-confined thiadiazole-based iodine adsorbent, characterized in that, The adsorbent material includes a silica zeolite support and thiadiazole guest molecules confined in the channels, pores, or interlayer confinement spaces of the silica zeolite support.

2. The all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 1, characterized in that, The all-silica zeolite carrier is an MFI-structured all-silica zeolite, Silicalite-1, or all-silica zeolite nanosheets NSL-1.

3. The all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 1, characterized in that, The thiadiazole guest molecule is one or more of 2-amino-1,3,4-thiadiazole, 5-amino-1,2,4-thiadiazole, 5-amino-1,2,3-thiadiazole, and 2-mercapto-5-methyl-1,3,4-thiadiazole.

4. The all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 1, characterized in that, The mass fraction of the thiadiazole guest molecules in the adsorbent material is 1-60 wt%.

5. A method for preparing the all-silica zeolite confined thiadiazole iodine adsorbent material according to any one of claims 1-4, characterized in that, Includes the following steps: The all-silica zeolite support is activated; thiadiazole guest molecules are dissolved in an organic solvent to obtain an impregnation solution; the impregnation solution is added to the activated all-silica zeolite support, and the thiadiazole guest molecules are mixed, ground or sonicated to allow them to enter the confined space of the all-silica zeolite; the resulting sample is dried and aged to obtain the adsorbent material.

6. The preparation method of the all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 5, characterized in that, The organic solvent is acetonitrile, and the concentration of thiadiazole guest molecules in the impregnation solution is 0.5-300 mg / mL.

7. The preparation method of the all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 5, characterized in that, The mass-to-volume ratio of the thiadiazole guest molecule to the organic solvent is 100-180 mg:1 mL; the mass ratio of the thiadiazole guest molecule to the activated all-silica zeolite carrier is 1-1.5:

1.

8. The preparation method of the all-silica zeolite confined thiadiazole iodine adsorbent material according to claim 5, characterized in that, The activation treatment is drying at 80-180℃ for 6-24 h or calcining at 250-450℃ for 2-8 h; the drying treatment is drying at 40-120℃ for 2-24 h; the aging treatment is treating at 70-130℃ for 6-96 h.

9. The application of the all-silica zeolite confined thiadiazole iodine adsorbent material according to any one of claims 1-4 in the capture and concentration of iodine species, characterized in that, The iodine species include I2, CH3I, organic iodine, radioactive iodine isotopes, and combinations thereof.

Images