A cationic adsorbent, its preparation method and application

Abstract

This invention discloses a cationic adsorbent, its preparation method, and its application. Under a protective atmosphere, compounds of formula 1 and formula 2 are mixed and reacted in a solvent containing a catalyst (Friedel-Crafts alkylation reaction) to obtain the cationic adsorbent. The structural formulas of compounds 1 and 2 are respectively: [formulas omitted for brevity], where n is 1 or 2, and X is selected from Cl or Br. This invention successfully synthesizes a structurally controllable ionic organic porous material with a high specific surface area through a combination of quaternization and Friedel-Crafts alkylation reactions. This material exhibits excellent specific surface area and achieves efficient adsorption of the dye Rhodamine B, diclofenac sodium, and carbon dioxide.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, specifically to a cationic adsorbent, its preparation method, and its application. Background Technology

[0002] Ionic organic porous materials, due to their strong covalent bonds, abundant ionic sites, and ion exchangeability, have shown broad application prospects in pollutant adsorption and carbon dioxide storage. The equilibrium ions in ionic organic porous materials can not only interact with specific guest molecules but also be tunable according to various application requirements. Furthermore, the weak electrostatic interaction between the host framework and the equilibrium ions promotes particle dispersion in water, while the framework structure incorporating specific functional groups can enhance the adsorption selectivity for pollutants. Compared with neutral porous materials and traditional ion exchange resins, ionic organic porous materials possess higher charge density and finely tunable ionic functional groups, thus exhibiting faster adsorption rates and higher adsorption capacities.

[0003] Although ionic organic porous materials have the advantages of abundant ion sites and ion exchangeability, most of them have a small specific surface area (<100), limiting their adsorption applications to specific ionic pollutants. Their adsorption capacity for organic pollutants and gases is weak, which greatly restricts their application in the field of pollutant adsorption.

[0004] Therefore, it is of great significance to study and develop an ionic organic porous material with controllable structure and high specific surface area to achieve efficient adsorption of pollutants and gases. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a cationic adsorbent, its preparation method, and its application. By combining quaternization and Friedel-Crafts alkylation reactions, a structurally controllable ionic organic porous material with a high specific surface area was successfully synthesized. This material exhibits excellent specific surface area and achieves efficient adsorption of dyes such as Rhodamine B, diclofenac sodium, and carbon dioxide.

[0006] To address the aforementioned technical problems, the first aspect of the present invention provides a cationic adsorbent having the following structure:

[0007] , where n is 1 or 2.

[0008] The cationic adsorbent of this invention has the advantages of large specific surface area, high stability, abundant adsorption sites, large adsorption capacity, and recyclability. It has successfully achieved highly efficient adsorption of the dye Rhodamine B, diclofenac sodium, and carbon dioxide; specifically, the maximum adsorption capacity for Rhodamine B reaches 728 mg / g, the maximum adsorption capacity for diclofenac sodium reaches 807 mg / g, and the maximum adsorption capacity for carbon dioxide reaches 54.8 cm⁻¹. 3 / g.

[0009] A second aspect of the present invention provides a method for preparing the cationic adsorbent described in the first aspect, comprising the following steps:

[0010] Under a protective atmosphere, compounds of formula 1 and formula 2 are mixed and reacted in a solvent containing a catalyst (Friedel-Crafts alkylation reaction) to obtain the cationic adsorbent;

[0011] The structural formulas of compounds of formula 1 and formula 2 are as follows:

[0012] , where n is 1 or 2, and X is selected from Cl or Br.

[0013] The synthesis method of this invention is simple to operate, and the synthesized cationic adsorbent has a high specific surface area, abundant exchangeable ion sites, and high thermal stability. It exhibits high activity in the adsorption of dye pollutants such as rhodamine B, diclofenac sodium, and carbon dioxide in water. Compared with the ionic porous material of Formula 1, its specific surface area is increased by 220 times, its carbon dioxide adsorption capacity is increased by 5 times, and it has excellent adsorption capacity for rhodamine B and diclofenac sodium. At the same time, the material also has excellent acid and alkali tolerance and recycling performance. Its excellent adsorption performance can be attributed to the large number of nitrogen-containing groups and ion sites introduced into the material, which can provide electrons, act as adsorption sites, enhance the electrostatic force between the adsorbent and the dye, and thus promote adsorption.

[0014] Furthermore, the molar ratio of the compound of formula 1, the compound of formula 2, and the catalyst is 1:(1-20):(1-24).

[0015] Furthermore, the catalyst is AlCl3 and / or FeCl3.

[0016] Furthermore, the reaction temperature is 85-120 °C, and the reaction time is 0.5-24 h. Preferably, the solvent is 1,2-dichloroethane and / or dichloromethane.

[0017] Furthermore, the reaction of compounds of formula 1 and formula 2 further includes filtration, washing, and vacuum drying steps. Preferably, the washing is performed sequentially with ethanol, tetrahydrofuran, N,N-dimethylformamide, methanol, and anhydrous acetone; the vacuum drying temperature is 50-120°C, and the time is 2-24 hours.

[0018] Furthermore, the preparation method of the compound of formula 1 includes the following steps:

[0019] Under a protective atmosphere, compounds of formula 3 and 4 are mixed and reacted in a solvent to obtain compound of formula 1.

[0020] The structural formulas of compounds of formula 3 and formula 4 are as follows:

[0021] .

[0022] Furthermore, the molar ratio of Br in compound 4 to amino group in compound 3 is 1:(0.8-1.2).

[0023] Furthermore, the reaction temperature of the compounds of formula 3 and formula 4 is 60-80°C, and the reaction time is 48-96 h. Preferably, the solvent is acetonitrile and / or N-methylpyrrolidone.

[0024] Furthermore, the reaction of compounds of formula 3 and formula 4 further includes filtration, washing, and vacuum drying steps. Preferably, the washing is performed sequentially with acetonitrile, tetrahydrofuran, and dichloromethane; the vacuum drying temperature is 50-120°C, and the time is 2-24 hours.

[0025] The third aspect of this invention provides the application of the cationic adsorbent described in the first aspect in pollutant absorption and carbon dioxide storage.

[0026] Furthermore, the contaminant is rhodamine B or diclofenac sodium.

[0027] The beneficial effects of this invention are:

[0028] The cationic adsorbent of this invention has the advantages of large specific surface area, high stability, abundant adsorption sites, large adsorption capacity, and recyclability, and has successfully achieved efficient adsorption of dyes Rhodamine B, diclofenac sodium, and carbon dioxide.

[0029] The synthesis method of this invention has simple operation steps. The introduction of a large number of nitrogen-containing groups and ionic sites can provide electrons, act as adsorption sites, enhance the electrostatic interaction between the adsorbent and the dye, thereby promoting adsorption and exhibiting excellent adsorption capacity. Attached Figure Description

[0030] 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.

[0031] Figure 1 This is the Fourier transform infrared spectrum of CON-1, the cationic organic porous material obtained in Example 1 of the present invention;

[0032] Figure 2 This is a powder X-ray diffraction pattern of CON-1, a cationic organic porous material obtained in Example 1 of the present invention;

[0033] Figure 3 The nitrogen adsorption-desorption curve of CON-1, a cationic organic porous material obtained in Example 1 of this invention;

[0034] Figure 4 The electron microscopy analysis results are those of CON-1, a cationic organic porous material obtained in Example 1 of this invention.

[0035] Figure 5 This is the solid-state carbon NMR spectrum of HC-CON-1, a cationic organic porous material obtained in Example 3 of the present invention;

[0036] Figure 6 This is the Fourier transform infrared spectrum of HC-CON-1, a cationic organic porous material obtained in Example 3 of the present invention.

[0037] Figure 7 This is a powder X-ray diffraction pattern of HC-CON-1, a cationic organic porous material obtained in Example 3 of the present invention;

[0038] Figure 8 The nitrogen adsorption-desorption curve of HC-CON-1, a cationic organic porous material obtained in Example 3 of this invention;

[0039] Figure 9 The electron microscopy analysis results are those of HC-CON-1, a cationic organic porous material obtained in Example 3 of this invention.

[0040] Figure 10 This is the solid-state carbon NMR spectrum of HC-CON-2, a cationic organic porous material obtained in Example 4 of the present invention;

[0041] Figure 11 This is the Fourier transform infrared spectrum of HC-CON-2, a cationic organic porous material obtained in Example 4 of the present invention;

[0042] Figure 12This is a powder X-ray diffraction pattern of HC-CON-2, a cationic organic porous material obtained in Example 4 of the present invention;

[0043] Figure 13 This is the nitrogen adsorption-desorption curve of HC-CON-2, a cationic organic porous material obtained in Example 4 of the present invention;

[0044] Figure 14 Electron microscopy analysis of HC-CON-2, a cationic organic porous material obtained in Example 4 of this invention;

[0045] Figure 15 These are the adsorption curves of HC-CON-2 for Rhodamine B at different times in Application Example 1 of the present invention;

[0046] Figure 16 This is the isothermal adsorption characterization of different concentrations of Rhodamine B by HC-CON-2 in Application Example 2 of the present invention;

[0047] Figure 17 This is an example of the adsorption characterization of Rhodamine B by HC-CON-2 at different pH values ​​in Application Example 3 of the present invention.

[0048] Figure 18 This is the cyclic adsorption test of HC-CON-2 for Rhodamine B in Application Example 4 of the present invention;

[0049] Figure 19 The adsorption curves of diclofenac sodium by HC-CON-2 at different times are shown in Application Example 5 of the present invention.

[0050] Figure 20 This is the isothermal adsorption characterization of diclofenac sodium at different concentrations by HC-CON-2 in Application Example 6 of the present invention;

[0051] Figure 21 This is an application example 7 of the present invention, which studies the adsorption of carbon dioxide by CON-1, HC-CON-1, and HC-CON-2. Detailed Implementation

[0052] 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.

[0053] This embodiment relates to a cationic adsorbent, which has the following structure:

[0054] Where n is 1 or 2. This cationic adsorbent has the advantages of large specific surface area, high stability, abundant adsorption sites, large adsorption capacity, and recyclability. It has successfully achieved efficient adsorption of the dye Rhodamine B, diclofenac sodium, and carbon dioxide; the maximum adsorption capacity for Rhodamine B can reach 728 mg / g, the maximum adsorption capacity for diclofenac sodium can reach 807 mg / g, and the maximum adsorption capacity for carbon dioxide can reach 54.8 cm⁻¹. 3 / g.

[0055] Another embodiment provides a method for preparing the cationic adsorbent described in the above embodiments, comprising the following steps:

[0056] Under a protective atmosphere, compounds of formula 1 and formula 2 are reacted in a solvent containing a catalyst (Friedel-Crafts alkylation reaction) to obtain the cationic adsorbent; wherein the structural formulas of compounds of formula 1 and formula 2 are:

[0057] Where n is 1 or 2, and X is selected from Cl or Br. The synthesis method in this embodiment is simple to operate, and the synthesized cationic adsorbent has a high specific surface area, abundant exchangeable ion sites, and high thermal stability. It exhibits high activity in the adsorption of dye pollutants such as rhodamine B, diclofenac sodium, and carbon dioxide in water. Compared with the ionic porous material of Formula 1, its specific surface area is increased by 220 times, its carbon dioxide adsorption capacity is increased by 5 times, and it has excellent adsorption capacity for rhodamine B and diclofenac sodium. Simultaneously, this material also has excellent acid and alkali tolerance and recyclability. Its excellent adsorption performance can be attributed to the large number of nitrogen-containing groups and ion sites introduced into the material, which can provide electrons, act as adsorption sites, enhance the electrostatic interaction between the adsorbent and the dye, thereby promoting adsorption.

[0058] In a preferred embodiment, the molar ratio of the compound of formula 1, the compound of formula 2, and the catalyst is 1:(1-20):(1-24); the catalyst is AlCl3 and / or FeCl3; the reaction temperature is 85-120 °C, and the reaction time is 0.5-24 h. Preferably, the solvent is 1,2-dichloroethane and / or dichloromethane. After the reaction of the compound of formula 1 and the compound of formula 2, the reaction further includes filtration, washing, and vacuum drying steps. Preferably, the washing is specifically performed sequentially with ethanol, tetrahydrofuran, N,N-dimethylformamide, methanol, and anhydrous acetone; the vacuum drying temperature is 50-120 °C, and the time is 2-24 h.

[0059] In a preferred embodiment, the preparation method of the compound of formula 1 includes the following steps:

[0060] Under a protective atmosphere, compound 3 (triethylenediamine) and compound 4 (1,2,4,5-tetra(bromomethyl)benzene) were reacted in a solvent to give compound 1; the structural formulas of compounds 3 and 4 are as follows:

[0061] .

[0062] In a preferred embodiment, the molar ratio of Br in Formula 4 to amino group in Formula 3 is 1:(0.8-1.2); the reaction temperature of Formula 3 and Formula 4 is 60-80°C, and the reaction time is 48-96 h. Preferably, the solvent is acetonitrile and / or N-methylpyrrolidone; after the reaction of Formula 3 and Formula 4, the reaction further includes filtration, washing, and vacuum drying steps. Preferably, the washing is specifically performed using acetonitrile, tetrahydrofuran, and dichloromethane sequentially; the vacuum drying temperature is 50-120°C, and the reaction time is 2-24 h.

[0063] Another embodiment provides the application of the cationic adsorbent described in the above embodiments in pollutant absorption and carbon dioxide storage, wherein the pollutant is rhodamine B or diclofenac sodium.

[0064] Example 1

[0065] This embodiment relates to a method for preparing a cationic organic porous material, including the following steps:

[0066] Under a nitrogen atmosphere, 1,2,4,5-tetra(bromomethyl)benzene (450 mg, 0.8 mmol), triethylenediamine (112 mg, 1.6 mmol), and 15 mL of acetonitrile were added sequentially to a round-bottom flask, and the reaction was carried out at 80 °C for 72 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed sequentially with acetonitrile, tetrahydrofuran, and dichloromethane, and dried at 80 °C for 10 h to obtain the cationic organic porous material CON-1 (compound of formula 1) in 81% yield.

[0067] Example 2

[0068] The difference between this embodiment and Example 1 is that the solvent acetonitrile is replaced with N-methylpyrrolidone, while other steps and parameters remain unchanged, to prepare the cationic organic porous material CON-2 with a yield of 83%.

[0069] Example 3

[0070] This embodiment relates to a method for preparing a cationic organic porous material with a large specific surface area, comprising the following steps:

[0071] Under a nitrogen atmosphere, the material CON-1 (101 mg, 0.13 mmol) prepared in Example 1, along with 1,4-dichlorobenzyl (222 mg, 1.3 mmol), ferric chloride (FeCl3, 421 mg, 2.6 mmol), and 15 mL of 1,2-dichloroethane, were added to a round-bottom flask, and the mixture was then reacted at 85 °C for 24 h. After the reaction was complete, the mixture was cooled to room temperature, filtered, and washed sequentially with ethanol, tetrahydrofuran, N,N-dimethylformamide, methanol, and anhydrous acetone. The resulting solid was extracted with tetrahydrofuran for 24 h, and then dried under vacuum at 80 °C for 10 h to obtain the high specific surface area cationic organic porous material HC-CON-1, with a yield of 71%.

[0072] Example 4

[0073] This embodiment relates to a method for preparing a cationic organic porous material with a large specific surface area, comprising the following steps:

[0074] Under a nitrogen atmosphere, CON-1 (198 mg, 0.25 mmol), 4,4'-bis(chloromethyl)biphenyl (628 mg, 2.5 mmol), ferric chloride (811 mg, 5.0 mmol), and 25 mL of 1,2-dichloroethane prepared in Example 1 were added to a round-bottom flask, and the mixture was reacted at 85 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed sequentially with ethanol, tetrahydrofuran, N,N-dimethylformamide, methanol, and anhydrous acetone. The resulting solid was extracted with tetrahydrofuran for 24 h and then dried at 80 °C for 10 h to obtain HC-CON-2, a high specific surface area ionic organic porous material with a yield of 78%.

[0075] Figure 1 The Fourier transform infrared spectrum of CON-1, the cationic organic porous material obtained in Example 1, proves the successful synthesis of material CON-1. Figure 2 The powder X-ray diffraction pattern of CON-1, the cationic organic porous material obtained in Example 1, shows that CON-1 has no crystalline form. Figure 3 The nitrogen adsorption-desorption curves for CON-1, the cationic organic porous material obtained in Example 1, show that the specific surface area of ​​CON-1 is 7.5 m². 2 / g, which is relatively small. Figure 4 Electron microscopy analysis of CON-1, the cationic organic porous material obtained in Example 1, shows that CON-1 has a spherical packing configuration.

[0076] Figure 5 Solid-state carbon NMR spectrum of HC-CON-1, a cationic organic porous material obtained in Example 3; Figure 6The Fourier transform infrared spectrum of HC-CON-1, a cationic organic porous material obtained in Example 3, is shown below. Figure 5-6 This proves the successful synthesis of material HC-CON-1. Figure 7 The powder X-ray diffraction pattern of HC-CON-1, a cationic organic porous material obtained in Example 3, shows that HC-CON-1 has no crystalline form. Figure 8 The nitrogen adsorption-desorption curve of HC-CON-1, a cationic organic porous material obtained in Example 3, shows that the specific surface area of ​​HC-CON-1 is 1058.2 m². 2 / g, which is 140 times that of the porous material CON-1 obtained in Example 1 before modification; Figure 9 Electron microscopy analysis of the cationic organic porous material HC-CON-1 obtained in Example 3 shows that HC-CON-1 has a honeycomb porous structure.

[0077] Figure 10 This is the solid-state carbon NMR spectrum of HC-CON-2, the ionic organic porous material obtained in Example 4. Figure 11 The Fourier transform infrared spectrum of HC-CON-2, the ionic organic porous material obtained in Example 4, is shown below. Figure 10-11 This proves the successful synthesis of material HC-CON-2. Figure 12 The powder X-ray diffraction pattern of HC-CON-2, the ionic organic porous material obtained in Example 4, shows that the material has no crystalline form. Figure 13 The nitrogen adsorption-desorption curve of HC-CON-2, the ionic organic porous material obtained in Example 4, shows that the specific surface area of ​​HC-CON-2 is 1659.9 m². 2 / g, which is 220 times that of the porous material CON-1 obtained in Example 1 before modification; Figure 14 Electron microscopy analysis of the ionic organic porous material HC-CON-2 obtained in Example 4 shows that HC-CON-2 has a honeycomb porous structure.

[0078] Application Example 1

[0079] The organic porous material HC-CON-2 obtained in Example 4 was dispersed in 5 mL of Rhodamine B (400 ppm) aqueous solution. After thorough stirring and adsorption for a certain period of time, the mixture was filtered through a needle filter (0.45 µm). The UV absorption peak of the filtrate was measured using a UV-Vis spectrophotometer. The adsorption efficiency was determined by comparing the intensity of the UV characteristic absorption peak before and after adsorption. Figure 15 As shown, the adsorption percentage of Rhodamine B by material HC-CON-2 gradually increased over time, reaching an adsorption rate of over 99% in 16 minutes, indicating that material HC-CON-2 can rapidly and effectively adsorb Rhodamine B in water.

[0080] Application Example 2

[0081] HC-CON-2 (5 mg) was dispersed in 6 mL of Rhodamine B aqueous solutions of different concentrations (200, 400, 600, 800, 1000, 1200 ppm). After thorough stirring and adsorption for 2.5 hours, the mixture was filtered through a 0.45 µm syringe filter. The UV absorption peak of the filtrate was measured using a UV-Vis spectrophotometer. The adsorption efficiency was determined by comparing the intensity of the characteristic UV absorption peaks before and after adsorption. Figure 16 As shown in the final equilibrium concentration after adsorption, the maximum adsorption capacity of material HC-CON-2 for Rhodamine B is 728 mg / g, indicating that material HC-CON-2 is an excellent dye adsorbent with potential application value.

[0082] Application Example 3

[0083] The organic porous material HC-CON-2 obtained in Example 4 was dispersed in 5 mL of Rhodamine B (200 ppm) aqueous solutions at different pH values ​​(pH=1, 3, 5, 7, 9, 12). After thorough stirring and adsorption for a certain period of time, the mixture was filtered through a needle filter (0.45 µm). The UV absorption peak of the filtrate was measured using a UV-Vis spectrophotometer. The adsorption efficiency was determined by comparing the intensity of the characteristic UV absorption peaks before and after adsorption. Figure 17 As shown, the adsorption rate of Rhodamine B by material HC-CON-2 did not change significantly under different pH conditions, indicating that material HC-CON-2 has excellent acid and alkali tolerance.

[0084] Application Example 4

[0085] The organic porous material HC-CON-2 obtained in Example 4 was dispersed in 50 mL of Rhodamine B (200 ppm) aqueous solution. After stirring thoroughly for 2 hours, the mixture was filtered through filter paper. The resulting solid was washed with ethanol solution until the filtrate was colorless to achieve regeneration. After drying, it could be recycled. The filtrate was analyzed using a UV-Vis spectrophotometer to determine the UV absorption peak. The adsorption efficiency was determined by comparing the intensity of the characteristic UV absorption peaks before and after adsorption. Figure 18 As shown, the adsorption efficiency of material HC-CON-2 remained above 85% after 5 cycles of adsorbing Rhodamine B, indicating that material HC-CON-2 has excellent recyclability.

[0086] Application Example 5

[0087] The organic porous material HC-CON-2 obtained in Example 4 was dispersed in 5 mL of diclofenac sodium (200 ppm) aqueous solution. After thorough stirring and adsorption for a certain period of time, the mixture was filtered through a needle filter (0.45 µm). The ultraviolet absorption peak of the filtrate was measured using a UV-Vis spectrophotometer. The adsorption efficiency was determined by comparing the intensity of the characteristic ultraviolet absorption peak before and after adsorption. Figure 19 As shown, the adsorption percentage of diclofenac sodium by material HC-CON-2 gradually increases with time, reaching an adsorption rate of over 95% in 30 minutes, indicating that material HC-CON-2 can rapidly and effectively adsorb diclofenac sodium in water.

[0088] Application Example 6

[0089] The organic porous material HC-CON-2 obtained in Example 4 was dispersed in 6 mL of aqueous solutions of diclofenac sodium at different concentrations (200, 400, 600, 800, and 1000 ppm). After thorough stirring and adsorption for 2.5 hours, the mixture was filtered through a 0.45 µm needle filter. The UV absorption peak of the filtrate was measured using a UV-Vis spectrophotometer. The adsorption efficiency was determined by comparing the intensity of the characteristic UV absorption peaks before and after adsorption. Figure 20 As shown, the maximum adsorption capacity of material CON-LDU-2 for diclofenac sodium is 807 mg / g, indicating that material CON-LDU-2 is an excellent adsorbent with potential application value.

[0090] Application Example 7

[0091] Materials CON-1, HC-CON-1, and HC-CON-2 were applied to carbon dioxide adsorption, such as Figure 21 As shown, at 273 K, the adsorption capacities of materials CON-1, HC-CON-1, and HC-CON-2 for carbon dioxide are 11.6 cm⁻¹, respectively. 3 / g, 47.7 cm 3 / g and 54.8cm 3 / g, it can be seen that after the specific surface area modification, the carbon dioxide adsorption capacity of the materials in Examples 3 and 4 was greatly improved.

[0092] 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 cationic adsorbent, characterized in that, The cationic adsorbent has the following structure: , where n is 1 or 2.

2. A method for preparing the cationic adsorbent according to claim 1, characterized in that, Includes the following steps: Under a protective atmosphere, compounds of formula 1 and formula 2 are mixed and reacted in a solvent containing a catalyst to obtain the cationic adsorbent. The structural formulas of compounds of formula 1 and formula 2 are as follows: , where n is 1 or 2, and X is selected from Cl or Br.

3. The method for preparing the cationic adsorbent as described in claim 2, characterized in that, The molar ratio of the compound of Formula 1, the compound of Formula 2, and the catalyst is 1:(1-20):(1-24).

4. The method for preparing the cationic adsorbent as described in claim 2, characterized in that, The catalyst is AlCl3 and / or FeCl3.

5. The method for preparing the cationic adsorbent as described in claim 2, characterized in that, The reaction temperature is 85-120 ℃, and the reaction time is 0.5-24 h.

6. The method for preparing the cationic adsorbent as described in claim 2, characterized in that, The preparation method of the compound of Formula 1 includes the following steps: Under a protective atmosphere, compounds of formula 3 and 4 are mixed and reacted in a solvent to obtain compound of formula 1. The structural formulas of compounds of formula 3 and formula 4 are as follows: 。 7. The method for preparing the cationic adsorbent as described in claim 6, characterized in that, The molar ratio of Br in compound 4 to amino group in compound 3 is 1:(0.8-1.2).

8. The method for preparing the cationic adsorbent as described in claim 6, characterized in that, The reaction temperature of the compounds of formula 3 and formula 4 is 60-80℃, and the reaction time is 48-96h.

9. The application of the cationic adsorbent of claim 1 in pollutant absorption and carbon dioxide storage.

10. The application as described in claim 9, characterized in that, The contaminant is either Rhodamine B or diclofenac sodium.

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