Calixarene-based azo polymer as well as preparation method and application thereof

Abstract

The invention discloses a calixarene-based azo polymer and a preparation method and application thereof, and the preparation method comprises the following steps: diazotizing 4, 4 '-(benzo [c] [1, 2, 5] thiadiazole-4, 7-diyl) diphenylamine in a solvent containing sodium nitrite and hydrochloric acid; adjusting the pH to be neutral, and adding a mixed solution of calixarene and sodium acetate for reaction to obtain the calixarene-based azo polymer. Calixarene with different cavity sizes and 4, 4 '-(benzo [c] [1, 2, 5] thiadiazole-4, 7-diyl) diphenylamine (BTD) are crosslinked through diazo coupling reaction, a series of novel calixarene-based azo polymers (MCAPs) are constructed, the MCAPs have excellent adsorption performance on iodine trianions (I3-) in water, and the MCAPs have important scientific significance and application value for promoting sustainable development of nuclear energy.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a calixarene-based azo polymer and its preparation method and application. Background Technology

[0002] Against the backdrop of continuously growing energy demand and increasingly severe climate change, nuclear energy, as an efficient and low-carbon energy form, is accelerating the transition to a low-carbon economy and gradually becoming an important alternative to fossil fuels.

[0003] However, the large-scale application of nuclear energy faces a key challenge: how to safely separate and dispose of spent fuel and radioactive nuclides released from nuclear accidents, especially iodine isotopes with high volatility and environmental mobility. This is particularly relevant for the safe separation and disposal of iodine tri-antion (I3) in water. - For the removal of [a substance], various technologies are currently available, including adsorption, precipitation, flocculation, membrane separation, biological treatment, and ion exchange. Among these, adsorption is considered one of the most promising treatment technologies due to its advantages such as high efficiency, low cost, simple operation, and easy regeneration.

[0004] Traditional adsorption materials (such as activated carbon and zeolite) generally suffer from limited adsorption capacity and insufficient selectivity; while emerging porous materials (such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) exhibit excellent performance in gas-phase iodine adsorption, but their adsorption of I3 in aqueous phase is limited. - The adsorption efficiency is generally not high, and is limited by factors such as complex synthesis process and high preparation cost.

[0005] Therefore, developing novel adsorption materials with high adsorption capacity, excellent selectivity, and good economic efficiency for the efficient removal of iodine tri-antions has become a key issue that urgently needs to be addressed in this field. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a calixarene-based azo polymer, its preparation method, and its applications. A series of novel calixarene-based azo polymers (MCAPs) are constructed by crosslinking calixarenes of different cavity sizes with 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine (BTD) via a diazo coupling reaction. - It has excellent adsorption properties and is of great scientific significance and application value for promoting the sustainable development of nuclear energy.

[0007] To address the aforementioned technical problems, the first aspect of the present invention provides a calixarene-based azo polymer having the following general structural formula:

[0008] ;

[0009] Where n is an integer between 1 and 10, preferably an integer between 1 and 5.

[0010] A second aspect of the present invention provides a method for preparing the calixarene-based azo polymer described in the first aspect, comprising the following steps:

[0011] S1, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine is diazotized in a solvent containing sodium nitrite and hydrochloric acid; wherein, sodium nitrite is used as a diazotizing agent, and under acidic conditions, sodium nitrite reacts with hydrochloric acid to generate nitrous acid, which then reacts with an aromatic primary amine to generate a diazonium salt, thereby converting the primary amino groups at both ends of the raw material 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine into diazonium salt groups;

[0012] S2. Adjust the pH to neutral and add a mixed solution of calixarene and sodium acetate to react and obtain the calixarene-based azo polymer; wherein, sodium acetate is used to adjust the pH to maintain a stable and suitable reaction environment during the coupling stage;

[0013] The structural formulas of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine and calixarenes are as follows:

[0014] , n is an integer between 1 and 10, preferably an integer between 1 and 5.

[0015] Calcineurins are a class of macrocyclic host molecules with unique cavity structures. Their upper and lower edges are easily functionalized, and the cavity size is adjustable. Among them, the cavity diameters of C[4]A (n=1), C[6]A (n=3), and C[8]A (n=5) are ~3.0 Å, ~7.6 Å, and ~11.7 Å, respectively, and they can selectively recognize guests of specific sizes through host-guest interactions. However, traditional calicineurins have problems such as high solubility, difficulty in recovery, and limited adsorption sites in adsorption applications. In this invention, calicineurins with different cavity sizes are crosslinked with 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine through a diazo coupling reaction to construct a series of novel calicineurin-based azo polymers, and their adsorption on I3 is studied. - The adsorption behavior reveals the crucial role of host-guest size matching in the adsorption process, where, when n=3, for I3 - The optimal adsorption capacity reached 664.10 mg g. -1 This is attributed to its moderate cavity size and I3 - The optimal matching of ions, the rich π-electron system and the charge transfer provided by the azo functional groups, and the rapid mass transfer channels provided by the unique hierarchical porous structure.

[0016] Meanwhile, calixarene-based azo polymers exhibit excellent selective adsorption capabilities, enabling the selective adsorption of triiodide anions even when multiple anions (molar concentration ratios up to 100:1) coexist. Furthermore, they demonstrate efficient adsorption under varying pH conditions.

[0017] The method for preparing the calixarene-based azo polymer of this invention is simple. Based on its high stability and the ability to construct adsorption sites, the calixarene-based azo polymer is positioned as a very promising candidate for the remediation of iodine water pollution, which is helpful for water purification and environmental remediation.

[0018] Furthermore, in S1, the diazotization temperature is 0-5℃ and the time is 0.5-2h; in S2, the reaction temperature is room temperature (25℃) and the time is 12-18h.

[0019] Furthermore, in S1, the pH of the diazotization system is <2.

[0020] Furthermore, the molar ratio of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine to sodium nitrite is 1:(2-3).

[0021] Furthermore, the molar ratio of the calixarene to 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine is 1:(2-4).

[0022] Furthermore, the molar ratio of the calixarene to sodium acetate is 1:(15-25).

[0023] Furthermore, in S2, after the reaction is complete, the mixture is washed sequentially with dilute hydrochloric acid, NN'-dimethylformamide (DMF), water, methanol, tetrahydrofuran (THF), methanol, and water, then extracted with methanol using a Soxhlet extract, and finally freeze-dried.

[0024] Furthermore, in S1, the solvent is a mixture of deionized water and DMF; in S2, the solvent of the mixed solution of calixarene and sodium acetate is DMF.

[0025] The third aspect of this invention provides the application of the calixarene-based azo polymer described in the first aspect in the removal of iodine tri-antions.

[0026] Furthermore, the application specifically involves mixing the system containing iodine tri-antions with the calixarene-based azo polymer to achieve the removal of iodine tri-antions.

[0027] The beneficial effects of this invention are:

[0028] This invention constructs a series of novel calixarene-based azo polymers (MCAPs) by crosslinking calixarenes of different cavity sizes with 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine (BTD) via a diazo coupling reaction. For I3 - It has excellent adsorption properties and is of great scientific significance and application value for promoting the sustainable development of nuclear energy.

[0029] The calixarene-based azo polymer of this invention has excellent selective adsorption capacity, and can selectively adsorb iodide tri-antions even when multiple anions coexist; it can also perform efficient adsorption under different pH conditions.

[0030] The method for preparing the calixarene-based azo polymer of this invention is simple. Furthermore, based on its high stability and the ability to construct adsorption sites, it has good application prospects in the removal of iodine tri-antion, which is helpful for water purification and environmental remediation. Attached Figure Description

[0031] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The FT-IR spectra (a, c, e) of the calixarene-based azo polymers of Examples 1-3 of this invention are shown. 13 C NMR spectra (b, d, f);

[0033] Figure 2 This is an XPS image of the calixarene-based azo polymer of Example 1 of the present invention;

[0034] Figure 3 These are SEM images (af) and TEM images (hk) of the calixarene-based azo polymers of Examples 1-3 of the present invention.

[0035] Figure 4 The PXRD spectra (ac) and contact angle experimental results (df) of the calixarene-based azo polymers of Examples 1-3 of the present invention are shown.

[0036] Figure 5 The TGA (ac) and BET (df) diagrams and pore size distribution diagrams (hj) of the calixarene-based azo polymers of Examples 1-3 of the present invention are shown.

[0037] Figure 6The UV-Vis absorption spectra (ac) of the calixarene-based azo polymers in Examples 1-3 of this invention, the nonlinear fitting (df) of the kinetic model of the iodide triantium, and the fitting (hj) of the pseudo-second-order linear model are shown.

[0038] Figure 7 The Langmuir model and Freundlich model fitting of the calixarene-based azo polymers of Examples 1-3 of the present invention for the iodide triantium are shown.

[0039] Figure 8 Examples 1-3 of this invention show the adsorption rates (ac) of iodide tri-anthioneins by the calixarene-based azo polymers under different anions and the adsorption rates (df) of iodide tri-anthioneins under different pH conditions. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] This embodiment relates to a calixarene-based azo polymer having the following general structural formula:

[0042] ;

[0043] Where n is an integer between 1 and 10, preferably an integer between 1 and 5.

[0044] This embodiment relates to a method for preparing a calixarene-based azo polymer, comprising the following steps:

[0045] S1,4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine is diazotized in a solvent in the presence of sodium nitrite and hydrochloric acid; wherein the diazotization is carried out at a temperature of 0-5°C for a time of 0.5-2 h.

[0046] S2. Adjust the pH to neutral and add a mixed solution of calixarene and sodium acetate to react and obtain the calixarene-based azo polymer; wherein the reaction temperature is room temperature (25°C) and the time is 12-18h;

[0047] The structural formulas of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine and calixarenes are as follows:

[0048] , n is an integer between 1 and 10, preferably an integer between 1 and 5.

[0049] In a preferred embodiment, the molar ratio of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine to sodium nitrite is 1:(2-3); the molar ratio of calixarene to 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine is 1:(2-4); and the molar ratio of calixarene to sodium acetate is 1:(15-25).

[0050] In a preferred embodiment, in S2, after the reaction is completed, the mixture is washed sequentially with dilute hydrochloric acid, DMF, water, methanol, THF, methanol, and water, then extracted with methanol using a Soxhlet extract, and finally freeze-dried.

[0051] In a preferred embodiment, in S1, the solvent is a mixture of deionized water and DMF; in S2, the solvent of the mixed solution of calixarene and sodium acetate is DMF.

[0052] Another embodiment provides the application of the calixarene-based azo polymer described in the above embodiments in the removal of iodine tri-antions, specifically: mixing the system containing iodine tri-antions with the calixarene-based azo polymer to achieve the removal of iodine tri-antions.

[0053] Example 1

[0054] This embodiment relates to a method for preparing the calixarene-based azo polymer C[4]A-Azo-BTD (n=1), which includes the following steps:

[0055] (1) Add 1.5 mmol (477 mg) of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine, 25 mL of deionized water, 25 mL of DMF, and 0.7 mL of concentrated hydrochloric acid to a 250 mL round-bottom flask. Stir the mixture for 30 min and then transfer it to a cryogenic reactor to cool. At 0–5 °C, slowly add 10 mL of sodium nitrite aqueous solution (3.1 mmol, 217 mg), controlling the dropping rate to maintain the temperature, and continue stirring for 30 min to complete the diazotization.

[0056] (2) The reaction solution was neutralized with dilute Na2CO3 solution and kept at 0-5 °C in a low-temperature reactor. A DMF solution (30 mL) containing calixarene C[4]A (0.75 mmol, 318 mg) and NaOAc·3H2O (15 mmol, 2.04 g) was slowly added. The reaction mixture was stirred overnight at room temperature, and a red solid precipitated. The precipitate was collected by filtration and washed successively with dilute hydrochloric acid, DMF, water, methanol, THF, methanol, and water. The product was then extracted with methanol by Soxhlet for 24 h and freeze-dried to obtain the product calixarene-based azo polymer C[4]A-Azo-BTD with a yield of 56%.

[0057] Example 2

[0058] This embodiment relates to the preparation method of calixarene-based azo polymer C[6]A-Azo-BTD (n=3). The difference from Example 1 is that C[4]A in step (2) is replaced with C[6]A, while other steps and parameters remain unchanged.

[0059] Example 3

[0060] This embodiment relates to the preparation method of calixarene-based azo polymer C[8]A-Azo-BTD (n=5). The difference from Example 1 is that C[4]A in step (2) is replaced with C[8]A, while other steps and parameters remain unchanged.

[0061] Test case

[0062] The reaction substrates C[4]A, C[6]A, C[8]A, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine and the products C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD from Examples 1-3 were subjected to FT-IR spectroscopy and 13 C NMR spectroscopy test results are referenced. Figure 1 In the FT-IR spectrum, a, c, and e are located in the 3100-3300 cm⁻¹ range. -1 The broad absorption band of the amino group almost completely disappears in the polymer spectrum; meanwhile, at 1412 cm⁻¹... -1 Characteristic stretching vibration peaks belonging to newly formed azo bonds (–N=N–) appeared at the location; the disappearance and appearance of these key functional group signals jointly confirm that the diazo coupling reaction has successfully occurred. Furthermore, refer to... Figure 1 b, d, f, solid state 13In the C NMR spectrum, the broad signal appearing in the 100-160 ppm range is attributed to carbon atoms on the aromatic ring, indicating the presence of benzene ring and heteroaromatic ring structures; the signal at about 31 ppm can be identified as the carbon atom of the methylene bridge (–CH2) in the calixarene skeleton; in addition, the characteristic peak observed near 122 ppm can be attributed to the aromatic ring carbon atom directly connected to the azo bond (–N=N–), which provides strong evidence for the successful covalent connection between calixarene and the azo unit. Figure 2 XPS images of C[4]A-Azo-BTD showed the presence of O, N and S elements, further verifying the success of the polymerization reaction.

[0063] Figure 3 The image in af is a SEM image of the calixarane-based azo polymers C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD from Examples 1-3. Figure 3 The image in hk is a TEM image of the calixarane-based azo polymers C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD in Examples 1-3. It can be seen that the material is a loose amorphous powder composed of a large number of submicron-sized spherical particles.

[0064] The crystallinity of C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD was analyzed by powder X-ray diffraction (PXRD). Figure 4 The medium AC value shows a broad peak at approximately 20-25° in the spectrum, confirming that the polymer is an amorphous material. Contact angle experiments yielded (…). Figure 4 The contact angles of the calixarene-based azo polymers C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD were 117°, 151°, and 133°, respectively, confirming their hydrophobicity.

[0065] Thermogravimetric analysis (TGA) was used to test the thermal stability of covalent organic polymers C[4]A-Azo-BTD, C[6]A-Azo-BTD, and C[8]A-Azo-BTD under a nitrogen atmosphere. Figure 5 The thermal degradation temperatures (corresponding to 10% mass loss) were 358.25 ℃ (C[4]A-BTD), 383.16 ℃ (C[6]A-BTD), and 344.64 ℃ (C[8]A-BTD), respectively, indicating that the polymer has excellent thermal stability. Furthermore, the BET and pore size distribution diagrams are shown in the figure. Figure 5As shown in the figure, the material structure contains both micropores and mesopores. The specific surface areas calculated by the model are: C[4]A-Azo-BTD is 48.93 m²·g⁻¹, C[6]A-Azo-BTD is 81.70 m²·g⁻¹, and C[8]A-Azo-BTD is 28.69 m²·g⁻¹. The total pore volumes evaluated at relative pressure P / P0 = 0.99 are 0.36 cm³·g⁻¹, 0.57 cm³·g⁻¹, and 0.21 cm³·g⁻¹, respectively. The pore size distribution curves obtained by fitting with nonlocal density functional theory (NLDFT) show that the material has a wide pore size distribution in the range of 1-120 nm. Among them, C[6]A-Azo-BTD has the highest specific surface area, the largest pore volume, and a relatively more concentrated pore size distribution. This is for I3 - Ions entering the pores provide the necessary spatial conditions.

[0066] Application examples

[0067] To investigate the adsorption behavior of the polymer as an adsorbent for removing iodine trioxide (IoD) contaminants from water, 30 mg of calixarene-based azo polymer was dispersed in 30 mL of a contaminant solution (25 ppm) at room temperature for adsorption kinetics studies. The mixture was then magnetically stirred at 600 rpm. Samples were taken at different time points and filtered through a 0.22 µm syringe filter to monitor the adsorption process. The concentration of IoD was analyzed by UV-Vis spectrophotometry. Figure 6 The adsorption kinetics of calixarene-based azo polymers were evaluated using a 25 ppm iodine tri-antion solution. Experimental data were fitted to pseudo-first-order and pseudo-second-order kinetic models, respectively. Figure 6 (dj). Compared with the pseudo-first-order dynamics model, the pseudo-second-order dynamics model shows a better fit (R0). 2 The results are closer to 1), and the theoretical adsorption capacity matches the experimental results more closely; detailed data are shown in Table 1. The data indicate that the adsorption of iodide trianoates by calixarene-based azo polymers follows pseudo-second-order kinetics, classifying it as chemisorption. The pseudo-second-order kinetic rate constant (k²) for iodide trianoates by calixarene-based azo polymers is 6.9 × 10⁻⁶. -3 g mg -1 min -1 6.37×10 -3 g mg -1 min -1 4.28×10 -3 g mg -1 min -1 .

[0068] Table 1

[0069]

[0070] A calixarene-based azo polymer (5 mg) was dispersed in 10 mL solutions containing different initial concentrations of iodine trioxide ions to test the polymer's maximum adsorption capacity for pollutants. To ensure equilibrium was established, the mixture was stirred at room temperature for 48 h. Furthermore, the adsorption data were fitted using Freundlich and Langmuir models to obtain the corresponding maximum adsorption capacity. The thermodynamic adsorption behavior was analyzed using Langmuir and Freundlich adsorption isotherm models. Figure 7 The fitting yielded the R of the calixarene-based azo polymer. 2 The values ​​are 0.934, 0.908, 0.932 and 0.977, 0.977, 0.975, respectively. The R-squared values ​​for the Freundlich model are... 2 The result is closer to 1. Referring to Table 2, this indicates that the adsorption behavior of calixarene-based azo polymers for iodine tri-antions is more consistent with the Freundlich model, indicating that the adsorption is multilayer adsorption. In addition, the maximum adsorption capacities of calixarene-based azo polymers C[4]A-Azo-BTD, C[6]A-Azo-BTD and C[8]A-Azo-BTD for iodine are 609.64 mg·g⁻¹, 664.10 mg·g⁻¹ and 563.76 mg·g⁻¹, respectively.

[0071] Table 2

[0072]

[0073] To investigate the selective adsorption performance of calixarene-based azo polymers for iodide trioxides under different anion interferences, 10 mg of calixarene-based azo polymers and 10 mL of solutions containing different anions (Br⁻, Cl⁻, HCO₃⁻, SO₄²⁻, and NO⁻) were mixed with I₃. - A multi-component mixed solution with a molar concentration ratio as high as 100:1 was stirred at room temperature for 24 h. The residual concentration of each ion in the solution was determined using a UV-Vis spectrophotometer. Figure 8 As shown in Figure ac, even under the coexistence of multiple interfering ions, the calixarene-based azo polymer can still efficiently and selectively adsorb iodine tri-antions, demonstrating that the calixarene-based azo polymer has excellent selective adsorption performance for iodine tri-antions.

[0074] To investigate the effect of different pH values ​​on the adsorption of iodine trioxide ions by calixarene-based azopolymer, 10 mg of calixarene-based azopolymer and 10 mL of iodine aqueous solutions at different pH values ​​were stirred at room temperature for 24 h. The residual concentrations of each ion in the solution were determined using a UV-Vis spectrophotometer. Figure 8As shown in the figure, even over a wide pH range, calixarene-based azo polymers can still efficiently adsorb iodide trioxide ions, demonstrating that calixarene-based azo polymers exhibit excellent adsorption performance for iodide trioxide ions over a wide pH range.

[0075] In summary, this invention uses calixarene as the main component and 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine as a crosslinking agent to obtain a calixarene-based azo polymer via a diazo coupling reaction, enabling it to adsorb iodine trioxide ions from water. The synthesis steps of the calixarene-based azo polymer are simple, and it possesses active sites. Furthermore, it exhibits excellent adsorption performance, with a maximum adsorption capacity reaching 664.10 mg / g. -1 Furthermore, it possesses excellent selective adsorption capabilities, enabling the selective adsorption of iodine trianoates even in the presence of multiple coexisting anions. Therefore, calixarene-based azo polymers are positioned as highly promising candidates for the remediation of iodine-contaminated water, contributing to water purification and environmental restoration.

[0076] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A calixarene-based azo polymer, characterized in that, It has the following general structural formula: ； Where n is an integer between 1 and 10.

2. A method for preparing the calixarene-based azo polymer according to claim 1, characterized in that, Includes the following steps: S1,4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine was diazotized in a solvent in the presence of sodium nitrite and hydrochloric acid; S2. Adjust the pH to neutral and add a mixed solution of calixarene and sodium acetate to react and obtain the calixarene-based azo polymer; The structural formulas of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine and calixarenes are as follows: , n is an integer between 1 and 10.

3. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, In S1, the diazotization temperature is 0-5℃ and the time is 0.5-2h; in S2, the reaction temperature is room temperature and the time is 12-18h.

4. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, The molar ratio of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine to sodium nitrite is 1:(2-3).

5. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, The molar ratio of the calixarene to 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diphenylamine is 1:(2-4).

6. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, The molar ratio of the calixarene to sodium acetate is 1:(15-25).

7. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, In S2, after the reaction is complete, the mixture is washed sequentially with dilute hydrochloric acid, NN'-dimethylformamide, water, methanol, tetrahydrofuran, methanol, and water, then extracted with methanol using a Soxhlet extract, and finally freeze-dried.

8. The method for preparing the calixarene-based azo polymer as described in claim 2, characterized in that, In S1, the solvent is a mixture of deionized water and NN'-dimethylformamide; in S2, the solvent for the mixture of calixarene and sodium acetate is NN'-dimethylformamide.

9. The application of the calixarene-based azo polymer of claim 1 in the removal of iodine tri-antions.

10. The application as described in claim 9, characterized in that, The specific application is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a missing section.] - The system is mixed with the calixarene-based azo polymer to achieve I3 - The removal of.

Images