Imidazolyl anionic polymers, methods of making and using the same

Abstract

This invention discloses an imidazole-based anionic polymer, its preparation method, and its applications, belonging to the field of environmental protection technology. It solves the problems of limited adsorption capacity, slow adsorption rate, and poor reusability of existing adsorbent materials. The imidazole-based anionic polymer contains at least one porphyrin ring and at least one imidazole ring, and has a specific surface area of ​​10 m². 2 ·g ‑1 -30 m 2 ·g ‑1 The average pore size is 20 nm–35 nm, and the average particle size is 200 nm–1000 nm. The anionic polymer of this invention is synthesized using a two-step method with mild reaction conditions, low synthesis cost, high yield, and is suitable for large-scale production. The prepared anionic polymer exhibits excellent adsorption properties and is suitable for use in various scenarios such as high-level radioactive wastewater from nuclear facilities, nuclear medicine wastewater, and groundwater containing TcO4. ‑ / ReO4 ‑ The separation and recycling of technetium has significant advantages, especially in the treatment of low-concentration technetium pollution, and can also realize the recycling and reuse of technetium resources.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, specifically relating to an imidazole-based anionic polymer, its preparation method, and its application. Background Technology

[0002] With the widespread application of nuclear energy in fields such as power supply, medical treatment, and hydrogen production, the discharge of radioactive waste liquids continues to increase, among which technetium (Tc) is mainly TcO4. - It exists in a form with a long half-life (2.13 × 10⁻⁶). 5 Technetium, characterized by its high mobility, high biotoxicity, and tendency to accumulate through water and the food chain, poses a long-term potential threat to ecosystems and public health. At the same time, as a valuable nuclear medicine resource, its efficient recovery has significant economic value.

[0003] Traditional methods for treating radioactive waste (such as evaporation and concentration, vitrification, and decay cell storage) suffer from drawbacks including low efficiency, high cost, and significant safety risks. Adsorption, on the other hand, has become the preferred method for treating TcO4 due to its high selectivity, ease of operation, low waste volume, and reusable materials. - The mainstream research direction for separation. Among existing adsorption materials, porous organic polymers (POPs) have tunable structures and good stability, but most of them suffer from problems such as limited adsorption capacity, slow adsorption rate, and poor reusability. Summary of the Invention

[0004] In view of the above problems, the purpose of this invention is to provide an imidazole-based anionic polymer, its preparation method and application, which solves the problems of limited adsorption capacity, slow adsorption rate and poor reusability of existing adsorbent materials.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: An imidazole-based anionic polymer comprising at least one porphyrin ring and at least one imidazole ring, having a specific surface area of ​​10 m²·g⁻¹ to 30 m²·g⁻¹, an average pore size of 20 nm to 35 nm, and an average particle size of 200 nm to 1000 nm.

[0006] In some embodiments, the following steps are included: S1. Dissolve 1-(4-imidazol-1-ylphenyl)imidazolium and 1-chloro-2,4-dinitrobenzene in a solvent and heat to react, to obtain 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt; S2. The 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt prepared in S1, 5,10,15,20-tetra(aminophenyl)porphyrin and solvent are heated and reacted to prepare the imidazolium-based anionic polymer.

[0007] In some embodiments, the mass ratio of 1-(4-imidazol-1-ylphenyl)imidazole to 1-chloro-2,4-dinitrobenzene in S1 is 1:3.9; the mass-volume ratio of 1-(4-imidazol-1-ylphenyl)imidazole to the solvent in S1 is 1:(80-100).

[0008] In some embodiments, the solvent in S1 is any combination of acetonitrile and 1,4-dioxane.

[0009] In some embodiments, the heating temperature in S1 is 80°C-100°C, and the reaction is carried out under reflux in an inert gas atmosphere.

[0010] In some embodiments, the reaction time in S1 is 65h-80h.

[0011] In some embodiments, the mass ratio of 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt to 5,10,15,20-tetra(aminophenyl)porphyrin in S2 is 1.82:1, the mass-to-volume ratio of 5,10,15,20-tetra(aminophenyl)porphyrin to the solvent is 1:(80-100), and the solvent in S2 is methanol and 1,4-dioxane.

[0012] In some embodiments, the heating temperature in S2 is 110°C-130°C.

[0013] In some embodiments, the reaction time in S2 is 65h-80h.

[0014] Another technical solution of the present invention is implemented as follows: Application of the imidazole-based anionic polymer as an adsorbent for pertechnetate and / or perrhenate.

[0015] Compared with existing technologies, the anionic polymer of this invention is synthesized using a two-step method with mild reaction conditions, low synthesis cost, high yield, and is easy to scale up for production. The prepared anionic polymer exhibits excellent adsorption properties and is suitable for TcO4 in various scenarios such as high-level radioactive waste liquids from nuclear facilities, nuclear medicine wastewater, and groundwater. - / ReO4 - The separation and recycling of technetium has significant advantages, especially in the treatment of low-concentration technetium pollution, and can also realize the recycling and reuse of technetium resources. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a synthesis diagram of a 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt provided in Example 1 of the present invention; Figure 2 This is a synthesis diagram of an imidazole-based porous organic polymer (TAPI) provided in Example 1 of the present invention; Figure 3 The 160 mg·L provided in Example 1 of this invention -1 Adsorption capacity at different pH values ​​at initial concentrations; Figure 4 The TAPI material provided in Embodiment 1 of the present invention in ReO4 - Adsorption capacity plots at different initial concentrations; Figure 5 This is a fitting diagram of the adsorption isotherm model of the TAPI material provided in Embodiment 1 of the present invention; Figure 6 This is a curve showing the change in TAPI adsorption capacity over equilibrium time, provided in Example 1 of the present invention. Figure 7 The image shows the linear fitting of the TAPI quasi-first-order dynamic model provided in Embodiment 1 of the present invention. Figure 8 The image shows the linear fitting of the TAPI quasi-second-order dynamic model provided in Embodiment 1 of the present invention. Figure 9 The graph shows the desorption rates measured under different desorption solutions; Figure 10a This is a composite image of the SEM images of TAPI material. Figure 10b This is an elemental distribution diagram of Cl; Figure 10c EDS spectrum of TAPI material; Figure 11 Fourier transform infrared spectra of TAP, I-Zincke salt, and TAPI materials; Figure 12a The N2 adsorption-desorption isotherm curve of TAPI; Figure 12b A pore size distribution diagram of TAPI; Figure 13 This is a nanoparticle size distribution diagram of TAPI; Figure 14TAG curve for TAPI; Figure 15a This is a composite image of the SEM images of TAPI-Re. Figure 15b This is a plot showing the element distribution of Re; Figure 15c EDS spectrum of TAPI-Re; Figure 16 Fourier transform infrared spectra of TAPI and TAPI-Re; Figure 17a XPS spectra of TAPI and TAPI-Re materials; Figure 17b This is the spectra of Re 4f after adsorption.

[0018] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation

[0019] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0021] An imidazole-based anionic polymer comprises at least one porphyrin ring and at least one imidazole ring. The number of porphyrin rings may be two, three, or four, and the number of imidazole rings may be two, four, six, or eight, or other numbers. The imidazole-based anionic polymers synthesized in Examples 1-3 have four porphyrin rings and eight imidazole rings.

[0022] Example 1 Synthesis of 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt (I-Zincke salt): 1 g of 1-(4-imidazol-1-ylphenyl)imidazolium and 3.9 g of 1-chloro-2,4-dinitrobenzene were dissolved in 100 mL of acetonitrile (CH3CN). The solution was refluxed at 90 °C for 72 h under a nitrogen atmosphere. After cooling, the solution was washed with an appropriate amount of acetonitrile and dried. 2.15 g of the product was obtained, with a yield of 73%. Figure 1 As shown.

[0023] Synthesis of imidazole-based porous organic polymer (TAPI): 1.82 g of I-Zincke salt and 1 g of 5,10,15,20-tetra(aminophenyl)porphyrin (TAP) were weighed and placed in a 250 mL round-bottom flask. 50 mL of methanol (MeOH) and 50 mL of 1,4-dioxane were added. The mixture was refluxed at 120 °C for 72 h. After washing with appropriate amounts of methanol and deionized water and drying, 1.36 g of the product was obtained, with a yield of 78.3%. Figure 2 As shown.

[0024] Example 2 Synthesis of 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt (I-Zincke salt): 1 g of 1-(4-imidazol-1-ylphenyl)imidazolium and 3.9 g of 1-chloro-2,4-dinitrobenzene were dissolved in 100 mL of acetonitrile (CH3CN). The solution was refluxed at 100 °C for 78 h under a nitrogen atmosphere. After cooling, the solution was washed with an appropriate amount of acetonitrile and dried. 2.1 g of the product was obtained, with a yield of 71%.

[0025] Synthesis of imidazole-based porous organic polymer (TAPI): 1.82 g of I-Zincke salt and 1 g of 5,10,15,20-tetra(aminophenyl)porphyrin (TAP) were weighed and placed in a 250 mL round-bottom flask. 40 mL of methanol (MeOH) and 40 mL of 1,4-dioxane were added. The mixture was refluxed at 130 °C for 78 h. After washing with appropriate amounts of methanol and deionized water and drying, 1.36 g of the product was obtained, with a yield of 77.8%.

[0026] Example 3 Synthesis of 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt (I-Zincke salt): 1 g of 1-(4-imidazol-1-ylphenyl)imidazolium and 3.9 g of 1-chloro-2,4-dinitrobenzene were dissolved in 100 mL of acetonitrile (CH3CN). The solution was refluxed at 80 °C for 65 h under a nitrogen atmosphere. After cooling, the solution was washed with an appropriate amount of acetonitrile and dried. 2.13 g of the product was obtained, with a yield of 71%.

[0027] Synthesis of imidazole-based porous organic polymer (TAPI): 1.82 g of I-Zincke salt and 1 g of 5,10,15,20-tetra(aminophenyl)porphyrin (TAP) were weighed and placed in a 250 mL round-bottom flask. 60 mL of methanol (MeOH) and 60 mL of 1,4-dioxane were added. The mixture was refluxed at 110 °C for 65 h. After washing with appropriate amounts of methanol and deionized water and drying, 1.35 g of the product was obtained, with a yield of 77.3%.

[0028] Example 4: Effect of solution pH on adsorption performance Weigh 2 mg of TAPI material into a 15 mL centrifuge tube and add 10 mL of 160 mg·L⁻¹. -1 ReO4 - The solutions were prepared by adjusting the pH to 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 with nitric acid or ammonia, respectively. After shaking for 16 h at room temperature (25 ℃), the solutions were centrifuged, and the supernatant was collected for analysis. The ReO4 content of the adsorbed solutions was determined by ICP-MS. - Concentration, and calculate the adsorption capacity under different pH conditions.

[0029] To investigate the effect of different pH values ​​on adsorption performance, nitric acid and ammonia were used to adjust the pH value of the solution, and the effect of TAPI on ReO4 at different pH values ​​was measured. - The adsorption capacity of TAPI for ReO4 at pH=3. - The adsorption capacity increased rapidly, reaching a peak of 205.23 mg·g⁻¹. -1 Then, with increasing pH, TAPI's effect on ReO4... - The adsorption capacity of TAPI for ReO4 gradually decreases. Under alkaline conditions, TAPI's adsorption capacity for ReO4... - The solution has almost no adsorption capacity. This may be due to the presence of OH groups. - The effect is significant; when the pH value is high, a large amount of OH- - Will with ReO4 - Competing for ion exchange sites. Simultaneously, the adsorption process is affected by protonation; the lone pair of electrons on the nitrogen atom of the imidazole ring readily interacts with H+ in the solution. +They combine to form positively charged cations, which then interact electrostatically with anions. As the pH increases, the H+ in the solution... + As the concentration decreases, the nitrogen atom of the imidazole ring undergoes deprotonation, reducing the positive charge and thus no longer attracting ReO4 via electrostatic interactions. - This resulted in poor adsorption capacity. Subsequent experiments were conducted at pH=3. Figure 3 As shown.

[0030] Example 5: Effect of initial concentration on adsorption performance Since the above pH results all showed peak adsorption capacity at pH=3, we chose to investigate the effect of initial concentration on adsorption capacity at pH=3.

[0031] Weigh 2 mg of the TAPI material prepared in Example 1 into a 15 mL centrifuge tube, and add 10 mL of the following concentrations: 20, 40, 80, 100, 120, 160, 250, 280, and 320 mg·L⁻¹, respectively. -1 ReO4 - The solution was prepared, pH adjusted to 3, and centrifuged after shaking at room temperature for 16 h. The supernatant was collected for analysis. The ReO4 content of the post-adsorption solution was determined by ICP-MS. - The solution was analyzed and the adsorption capacity at different initial concentrations was calculated.

[0032] The adsorption capacity of TAPI material at different initial concentrations was determined. The results showed that the adsorption capacity increased with increasing initial concentration C0. When the initial concentration was approximately 250 mg·L⁻¹, the adsorption capacity increased. -1 At that time, the adsorption capacity was 319.57 mg·g. -1 ,like Figure 4 As shown.

[0033] The experimental results were fitted using the Langmuir model, Freundlich model, and Temkin model to further explore the effect of TAPI material on ReO4. - Adsorption performance. C e (mg·L) -1 () represents the ReO4 in the solution at adsorption equilibrium. - Concentration. By comparing the fitting results of the three models... R 2 The Freundlich model showed the highest goodness of fit and was better suited to describing the TAPI-ReO4 pair. - The adsorption process indicates that the surface of the material is non-uniform, and the adsorption process likely occurs in the form of multilayer adsorption. (Freundlich model parameters) n=2.91>2, indicating that the adsorption process is more likely to occur under these adsorption conditions. The fitting results of the TAPI adsorption isotherm model are as follows: Figure 5 As shown in Table 1, the fitting parameters are as follows.

[0034] Table 1 Fitting parameters of the adsorption isotherm model

[0035] Example 6: Effect of equilibrium time on adsorption performance Weigh 2 mg of TAPI material into a 15 mL centrifuge tube, and add 10 mL of 80 mg·L⁻¹. -1 ReO4 - The solution was adjusted to pH 3 with nitric acid and shaken at room temperature for 30 min, 1 h, 2 h, 4 h, 12 h, 24 h, 48 h, and 72 h, respectively. After shaking, the solution was centrifuged, and the supernatant was used to determine the ReO4 content after adsorption by ICP-MS. - The concentration was determined, and the adsorption capacity at different shaking times was calculated. The results showed that the adsorption capacity gradually increased with increasing reaction time until equilibrium was reached. TAPI for ReO4 - The adsorption rate is relatively slow, and the adsorption capacity reaches equilibrium after 24 hours, stabilizing at approximately 200 mg·g⁻¹. -1 Approximately 16.19 m². After characterization, TAPI's BET specific surface area is only 16.19 m². 2 ·g -1 This indicates that the material provides a limited number of effective adsorption sites. Although its average pore size is relatively large at 29.19 nm, which is beneficial for ReO4 in solution... - Rapid diffusion, but due to the limited number of adsorption sites, ReO4 - It is difficult to capture quickly. This is likely the main reason for the slow adsorption rate, such as... Figure 6 As shown.

[0036] To further analyze the effect of TAPI on ReO4 - The adsorption behavior was assessed using pseudo-first-order and pseudo-second-order kinetic models to fit the experimental data. The two fitting models... R 2 The results were 0.9518 and 0.9994, respectively, for TAPI against ReO4. - The adsorption process is more consistent with the pseudo-second-order kinetic model, indicating that its adsorption process is mainly chemisorption with ion exchange as the primary mode, such as... Figure 7 and Figure 8 As shown.

[0037] Example 7: Ion Selectivity Weigh 2 mg of the TAPI material prepared in Example 1 into a 15 mL centrifuge tube, and add 10 mL of 160 mg·L⁻¹.-1 ReO4 - The solution was prepared by adding competing ions NO3- in molar ratios of 1:1, 10:1, and 100:1, respectively. - SO4 2- The pH was adjusted to 3, and the mixture was shaken at room temperature for 16 h before centrifugation. The supernatant was collected for analysis. The ReO4 content of the solution after adsorption was determined by ICP-MS. - Concentration, calculate NO3 - SO4 2- The adsorption capacities when present separately and together. The partition coefficient is calculated using the following formula. K d value.

[0038]

[0039] in, It is ReO4 - The initial concentration of the solution, It is ReO4 - The equilibrium concentration of the solution, It is the volume of the solution. It refers to the quality of the TAPI material.

[0040] In actual radioactive waste liquids and groundwater, there are often various interfering anions, among which NO3- - and SO4 2- Especially common. Therefore, NO3 was selected. - and SO4 2- As competing ions, the influence of the presence of competing ions on adsorption performance was investigated.

[0041] When there are no interfering anions in the solution, TAPI has an effect on ReO4. - Allocation coefficient K d It is 1.97×10 3 The relative adsorption capacity percentage is calculated based on this. (Single NO3) - When it exists, when NO3 - With ReO4 - When the molar ratio is 1:1 and 10:1, the relative adsorption capacity can reach over 90%. K d The values ​​are 1.77 × 10 3 and 1.80×10 3 NO3 - With ReO4 - With a molar ratio of 100:1, the relative adsorption capacity decreased to 46.50%. K d Decreased to 7.57×10 2 Single SO42- When present, with a molar ratio of 10:1, the relative adsorption capacity can still be maintained above 90%. K d It is 1.73×10 3 When the molar ratio is 100:1, the relative adsorption capacity decreases to 74.36%. K d The value is 1.33 × 10 3 Compared to NO3 - SO4 2- The effect on adsorption performance is relatively small. When NO3... - and SO4 2- When both are present, under the condition of 100 times excess anion, the relative adsorption capacity is 49.93%. K d The value can still reach 8.22×10 2 It still exhibits good adsorption capacity. The results show that TAPI material has good adsorption capacity for ReO4. - It exhibits good selectivity and anti-interference capabilities, as shown in Table 2.

[0042] Table 2 TAPI Material NO3 - SO4 2- Adsorption rate and partition ratio at different molar ratios in the presence of

[0043] Example 8: Low-concentration adsorption experiment Weigh 2 mg of the TAPI material prepared in Example 1 into a 15 mL centrifuge tube, and add ReO4. - The solution concentration is 1 mg·L -1 With a pH of 3, the mixture was continuously shaken overnight (16 h). The removal rate of the imidazole material was calculated using the following formula. (%).

[0044]

[0045] The TAPI material was measured at an initial concentration of 1 mg·L⁻¹. -1 Adsorption performance under certain conditions. Results show that TAPI materials can also adsorb solution concentrations from the ppm level (mg·L⁻¹). -1 The concentration of ng·mL decreased to the ppb level. -1 ), for ReO4 - The removal rate reached 64.05%, demonstrating high adsorption capacity, as shown in Table 3.

[0046] Table 3. Adsorption capacity and removal rate at low concentrations under pH=3 conditions.

[0047] Example 9: Desorption and Repeatability Experiment Selection of elution buffer: Weigh 2 mg of the TAPI material prepared in Example 1 into a 15 mL centrifuge tube, and add ReO4. - The solution concentration is 80 mg·L -1 After adjusting the pH to 3 and shaking continuously overnight, the ReO4 content after adsorption was measured. - Given the solution concentration, calculate the adsorption capacity. (0.1 mol·L⁻¹) -1 HCl, 1 mol·L -1 HCl, 3 mol·L -1 HCl, 1 mol·L -1 NaCl solution was used as the eluent. 10 mL of each solution was added to the adsorbed material for desorption, and ReO4 was measured. - Solution concentrations were determined and desorption rates were calculated. Results showed that the desorption effects of 0.1M HCl, 1M HCl, and 3M HCl were essentially the same, with desorption rates only exceeding 70%, indicating poor desorption performance of the TAPI material. Furthermore, experiments revealed that when using low-acidity 0.1M HCl as the eluent, complete separation could not be achieved during desorption centrifugation, resulting in slight dissolution in the acidic solution. Significant material mass loss occurred during the second adsorption-desorption cycle. Therefore, the TAPI material does not possess reusable properties. Desorption rate results are as follows: Figure 9 As shown.

[0048] Scanning electron microscopy and elemental analysis were performed on the synthesized TAPI material, as shown in Figure 10. Figure 10a These are SEM images of TAPI material. Figure 10b This is an elemental distribution diagram of Cl. Figure 10c This is the EDS spectrum of the TAPI material. The SEM image reveals that the TAPI material has a rough surface, with tightly bound particles forming a clump-like structure that is stacked on top of each other, and large internal pores. The EDS spectrum shows characteristic peaks for chlorine, and the chlorine element exhibits a uniform and relatively dense distribution in the elemental distribution map. The experiment demonstrates that Cl was successfully grafted onto the TAPI material. The SEM and EDS results of TAPI are shown in Figure 10, and the elemental analysis results are shown in Table 4.

[0049] Table 4 Elemental Analysis of TAPI Materials

[0050] Fourier transform infrared (FT-IR) spectroscopy analysis was performed on the matrix and the synthesized materials. The black curve represents the FT-IR spectrum of the matrix porphyrin material TAP, the red curve represents the FT-IR spectrum of the synthesized product TAPI, and the blue curve represents the FT-IR spectrum of I-Zincke salt. Comparison of the three FT-IR curves shows that the spectrum at 3216.81 cm⁻¹... -1 The absorption peak at 1530.82 cm⁻¹ corresponds to the stretching vibration of -NH₂ in TAP. This characteristic peak disappears in the FT-IR curve of TAPI, indicating that -NH₂ has successfully participated in the reaction. -1 The absorption peak originates from the stretching vibration peak of -NO2 in the I-Zincke salt. This characteristic peak shows a significant decrease in intensity in the FT-IR curve of TAPI, but does not completely disappear, indicating that the -NO2 portion participated in the synthesis reaction, with a small amount remaining after the reaction. The imidazolyl Zincke salt was successfully grafted onto the porphyrin matrix, and the target product TAPI was successfully synthesized, as shown below. Figure 11 As shown.

[0051] N2 adsorption-desorption analysis was performed on TAPI materials. Figure 12a This is the N2 adsorption-desorption isotherm of TAPI. Its specific surface area is calculated to be 16.19 m². 2 ·g -1 . Figure 12b Figure 12 shows the pore size distribution of TAPI. The calculated average pore size is 29.19 nm. TAPI is a mesoporous material.

[0052] Nanoparticle size analysis was performed on the TAPI material. The results showed that the particles were mainly concentrated between approximately 200-1000 nm, with an average particle size of 618.70 nm. The material exhibited particle aggregation. Figure 13 As shown.

[0053] Thermogravimetric analysis (TGA) was performed on the synthesized TAPI material. Under a nitrogen atmosphere, the TAPI material was heated to 800°C at a heating rate of 10 °C / min, and the curves showed three distinct weight loss stages. The first stage occurred around 160 °C, with a mass loss of approximately 0.92%, corresponding to the evaporation of moisture and residual solvent in the material. The second stage (160–410 °C) saw a mass loss of approximately 22.98%, mainly attributed to the thermal decomposition of unreacted nitro and amino residues in the matrix material. The weight loss was more significant in this stage, reasonably suggesting that the material's backbone may retain more unreacted groups at its ends. Furthermore, it was found that imidazole-related ligands cleaved above approximately 300 °C, suggesting a possible mass loss due to the decomposition of the imidazole ring. The third stage (410–800 °C) saw a mass loss of approximately 27.52%, attributed to the cleavage of the porphyrin backbone and imidazole ring in the TAPI material at high temperatures. After heating to 800 °C, the residual weight of the material still reached 48.58%. The results show that TAPI materials possess excellent thermal stability, such as Figure 14 As shown.

[0054] To further explore the effect of TAPI on ReO4 - The adsorption mechanism of the adsorption process was also characterized, and the adsorbed material (TAPI-Re) was also characterized, with the following results: Scanning electron microscopy (SEM) and elemental analysis of TAPI-Re were performed, as shown in Figure 15. The SEM morphology reveals an irregular, paper-like structure with interlaced, tilted stacked layers and numerous pores. The elemental distribution diagram shows a uniform distribution of Re, and the EDS spectrum also shows peaks for rhenium and Cl. - ReO4 - The transfer was successful onto the material. The SEM and EDS results of TAPI-Re are shown in Figure 15, and the elemental analysis results are shown in Table 5.

[0055] Table 5 Elemental Analysis of TAPP Materials

[0056] Fourier transform infrared spectroscopy analysis was performed on TAPI-Re. The black curve represents the infrared spectrum of TAPI before adsorption, and the red curve represents the infrared spectrum of TAPI-Re after adsorption. Comparison revealed that at 908.76 cm⁻¹... -1 The TAPI-Re curve shows an appearance originating from ReO4. - The stretching vibration peak of Re-O indicates that Re(VII) is in the form of ReO4. - The form of exchange is applied to the material, such as Figure 16 As shown.

[0057] X-ray photon energy dispersive spectroscopy (XPS) analysis was performed on TAPI and TAPI-Re materials, as shown in Figure 17. Figure 17a These are the XPS spectra of the material before and after adsorption. The characteristic peak of Cl 2p is at 196.23 eV, which disappears after adsorption, and a characteristic peak of Re 4f appears at 44.77 eV, indicating that Cl in the TAPI material... - With ReO4 - Ion exchange occurred. Figure 17b This is the spectra of Re 4f after adsorption, compared with the standard KReO4 XPS spectrum (BE). 4f 7 / 2 Compared to 46.2 eV, the peak value decreased by 1.43 eV, which may be due to the interaction with the adsorption sites. During the adsorption process, rhenium is converted into ReO4. - The forms are interchanged as shown in Figure 17.

[0058] It should be understood that the above are merely illustrative examples and do not constitute any limitation on the technical solutions of the present invention. In specific applications, those skilled in the art can make settings as needed, and the present invention does not impose any restrictions on this.

[0059] It should be noted that the steps described above are merely illustrative and do not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of them to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here. The steps of the method described in this application are not limited to being executed sequentially according to the order in the specification; without changing the core technical solution, the execution order of some steps can be adjusted, or they can be implemented in parallel, or steps can be omitted or added in different scenarios. The above modifications or equivalent substitutions do not affect the substantive content of the technical solution of this application and should all fall within the scope of protection of this application.

[0060] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. The scope of protection of this application should be determined by the scope of the claims. Although this application has disclosed the preferred embodiment above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall fall within the scope of the technical solution of this application.

Claims

1. An imidazole-based anionic polymer, characterized in that, The imidazole-based anionic polymer contains at least one porphyrin ring and at least one imidazole ring, and has a specific surface area of ​​10 m². 2 ·g -1 -30 m 2 ·g -1 The average pore size is 20 nm-35 nm, and the average particle size is 200 nm-1000 nm.

2. A method for preparing the imidazole-based anionic polymer as described in claim 1, characterized in that, Includes the following steps: S1. Dissolve 1-(4-imidazol-1-ylphenyl)imidazolium and 1-chloro-2,4-dinitrobenzene in a solvent and heat to react, to obtain 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt; S2. The 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt prepared in S1, 5,10,15,20-tetra(aminophenyl)porphyrin and solvent are heated and reacted to prepare the imidazolium-based anionic polymer.

3. The method for preparing the imidazole-based anionic polymer according to claim 2, characterized in that, The mass ratio of 1-(4-imidazol-1-ylphenyl)imidazole to 1-chloro-2,4-dinitrobenzene in S1 is 1:3.9; the mass-volume ratio of 1-(4-imidazol-1-ylphenyl)imidazole to the solvent in S1 is 1:(80-100).

4. The method for preparing the imidazole-based anionic polymer according to claim 2 or 3, characterized in that, The solvent in S1 is any combination of acetonitrile and 1,4-dioxane.

5. The method for preparing the imidazole-based anionic polymer according to claim 2 or 3, characterized in that, The heating temperature in S1 is 80℃-100℃, and the reaction is carried out under reflux in an inert gas atmosphere.

6. The method for preparing the imidazole-based anionic polymer according to claim 4, characterized in that, The reaction time in S1 is 65-80 hours.

7. The method for preparing the imidazole-based anionic polymer according to claim 4, characterized in that, In S2, the mass ratio of 1-(4-imidazol-1-ylphenyl)imidazolium Zincke salt to 5,10,15,20-tetra(aminophenyl)porphyrin is 1.82:1, the mass-to-volume ratio of 5,10,15,20-tetra(aminophenyl)porphyrin to the solvent is 1:(80-100), and the solvent in S2 is methanol and 1,4-dioxane.

8. The method for preparing the imidazole-based anionic polymer according to claim 6, characterized in that, The heating temperature in S2 is 110℃-130℃.

9. The method for preparing the imidazole-based anionic polymer according to claim 7, characterized in that, The reaction time in S2 is 65-80 hours.

10. The use of the imidazole-based anionic polymer as described in any one of claims 2-9 as an adsorbent for pertechnetate and / or perrhenate.

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