Pyridine resins, methods of making and uses thereof

Abstract

This invention discloses a pyridine resin, its preparation method, and its uses. The preparation method of the pyridine resin of this invention includes the following steps: 1) mixing styrene, divinylbenzene, an initiator, and a porogen to form an organic phase, adding the organic phase to a dispersant solution for reaction, to obtain styrene-based copolymer crosslinked microspheres; 2) swelling the styrene-based copolymer crosslinked microspheres obtained in step 1), then adding a Lewis acid catalyst for reaction, to obtain chloromethylated crosslinked microspheres; 3) swelling the chloromethylated crosslinked microspheres obtained in step 2), then adding pyridine and an acid-binding agent for reaction, to obtain the pyridine resin. The pyridine resin prepared by this invention has a good adsorption effect on uranium ions in acidic uranium-containing wastewater.

Description

Technical Field

[0001] This invention relates to a pyridine resin, its preparation method, and its uses. Background Technology

[0002] Uranium mining and industrial uranium extraction processes generate large amounts of uranium-containing wastewater, with uranium concentrations reaching 10–100 mg / L. Uranium is radioactive and chemically toxic; if released into the environment, it will cause serious harm.

[0003] Currently, methods for treating uranium-containing wastewater include ion exchange, chemical precipitation, evaporation and concentration, membrane separation, and biochemical methods. Among these, ion exchange is a relatively efficient, economical, and reliable method. The principle of ion exchange is that when an ion exchange resin comes into contact with radioactive wastewater, the exchangeable functional groups on the resin interact with the uranium ions in the wastewater, adsorbing them onto the resin and thus removing the uranium ions from the wastewater. Ion exchange resins are high-polymer electrolytes with a three-dimensional network structure containing functional groups. Their advantages include high treatment capacity, high adsorption capacity, ability to remove various ions, regeneration capability, and long service life.

[0004] However, due to the weak adsorption selectivity of the functional groups of existing ion exchange resins for uranium, the adsorption capacity and adsorption efficiency of ion exchange resins for uranium are not ideal. Summary of the Invention

[0005] In view of this, one object of the present invention is to provide a method for preparing a pyridine resin. The obtained pyridine resin has good uranium adsorption capacity. Another object of the present invention is to provide a pyridine resin obtained by the above-described preparation method. A further object of the present invention is to provide uses for the above-described pyridine resin.

[0006] The present invention achieves the above objectives using the following technical solutions.

[0007] On one hand, the present invention provides a method for preparing pyridine resin, comprising the following steps:

[0008] 1) Styrene, divinylbenzene, initiator and porogen are mixed to form an organic phase. The organic phase is added to a dispersant solution and reacted at 50-95°C to obtain styrene skeleton copolymer crosslinked microspheres.

[0009] Wherein, the weight of the divinylbenzene is 6-20 wt% of the total weight of styrene and divinylbenzene; the weight of the initiator is 0.1-2 wt% of the total weight of styrene and divinylbenzene; the weight ratio of the porogen to the total weight of styrene and divinylbenzene is (0.1-1):1; and the weight ratio of the dispersant solution to the organic phase is (1-6):1.

[0010] 2) The styrene skeleton copolymer cross-linked microspheres obtained in step 1) are swollen, and then Lewis acid catalyst is added. The reaction is carried out at 30-90°C to obtain chloromethylated cross-linked microspheres; wherein the weight ratio of the Lewis acid catalyst to the styrene skeleton copolymer cross-linked microspheres is (0.1-0.5):1.

[0011] 3) The chloromethylated cross-linked microspheres obtained in step 2) are swollen, and then pyridine and an acid-binding agent are added. The mixture is reacted at 50-90°C to obtain pyridine resin. The weight ratio of pyridine to chloromethylated cross-linked microspheres is (3-6):1; the weight ratio of acid-binding agent to chloromethylated cross-linked microspheres is (0.05-0.5):1.

[0012] According to one embodiment of the present invention, preferably, in step 1), the dispersant solution can be an aqueous dispersant solution with a mass concentration of 0.2 to 5 wt%, preferably 0.5 to 2 wt%.

[0013] The dispersant may be selected from at least one of polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyethylene glycol, sodium lauryl sulfate, carboxymethyl cellulose, and carboxypropyl methyl cellulose; preferably, it may be selected from at least one of polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and sodium lauryl sulfate.

[0014] According to one embodiment of the present invention, preferably, the method for preparing the dispersant solution is as follows:

[0015] Add the dispersant to the solvent and heat until the dispersant is completely dissolved.

[0016] The heating temperature can be 40–90℃; preferably 50–80℃. The heating time can be 0.5–3 hours; preferably 1–2 hours.

[0017] According to the preparation method of the present invention, preferably, in step 1), the initiator is selected from at least one of benzoyl peroxide and azobisisobutyronitrile; preferably benzoyl peroxide or azobisisobutyronitrile. The pore-forming agent is selected from at least one of liquid paraffin and petroleum ether; preferably liquid paraffin or petroleum ether.

[0018] In step 1), styrene is used as a monomer and divinylbenzene is used as a crosslinking agent. The weight of the divinylbenzene can be 6-20 wt% of the total weight of styrene and divinylbenzene; preferably 9-18 wt%. The weight of the initiator can be 0.1-2 wt% of the total weight of styrene and divinylbenzene; preferably 0.5-1.5 wt%. The weight ratio of the porogen to the total weight of styrene and divinylbenzene can be (0.1-1):1; preferably (0.5-1):1. The weight ratio of the dispersant solution to the organic phase can be (1-8):1; preferably (2-6):1.

[0019] In step 1), the reaction is a curing reaction, and the reaction temperature can be 50–95°C; preferably 60–90°C. The reaction time can be 6–20 h, preferably 8–18 h.

[0020] According to one embodiment of the present invention, after the reaction in step 1) is completed, the product can be boiled at 100°C and dried to obtain styrene skeleton copolymer crosslinked microspheres.

[0021] In this invention, the boiling time can be 1 to 5 hours, preferably 2 to 3 hours. The drying temperature can be 50 to 95°C, preferably 60 to 90°C; the drying time can be 1 to 5 hours, preferably 2 to 4 hours.

[0022] In step 1), controlling the ratio of reaction raw materials and reaction conditions within the above range is beneficial to the progress of the curing reaction and more conducive to the generation of qualified styrene skeleton copolymer crosslinked microspheres.

[0023] According to the preparation method of the present invention, preferably, in step 2), the Lewis acid catalyst is selected from at least one of FeCl3, TiCl4, ZnCl2, and AlCl3; more preferably, it is selected from at least one of FeCl3, ZnCl2, and AlCl3.

[0024] In this invention, the weight ratio of the Lewis acid catalyst to the styrene skeleton copolymer crosslinked microspheres can be (0.1-0.5):1; preferably (0.2-0.5):1.

[0025] According to the preparation method of the present invention, preferably, in step 2), the styrene skeleton copolymer crosslinked microspheres obtained in step 1) are swollen with chloromethyl ether. The weight ratio of chloromethyl ether to styrene skeleton copolymer crosslinked microspheres can be (2-8):1, preferably (3-6):1.

[0026] In step 2), the swelling time of the styrene skeleton copolymer crosslinked microspheres obtained in step 1) with chloromethyl ether can be 1 to 5 hours, preferably 1 to 3 hours.

[0027] In step 2), the reaction is a reflux reaction and can be carried out in any reflux reaction apparatus known in the art. The reaction temperature can be 30–90°C; preferably 40–80°C. The reaction time can be 8–36 h, preferably 10–30 h.

[0028] According to one embodiment of the present invention, after the reaction in step 2) is completed, the product can be washed and dried with an aqueous solution of C1 to C5 alkyl alcohols to obtain chloromethylated crosslinked microspheres.

[0029] In this invention, the C1-C5 alkyl alcohol is a C1-C3 n-alkyl alcohol; preferably, it is at least one of methanol and ethanol. The volume ratio of the C1-C5 alkyl alcohol to water can be 1:2 to 2:1; preferably 1:1.

[0030] The drying process is vacuum drying, and the drying temperature can be 30-90℃, preferably 45-85℃; the drying time can be 1-5 hours, preferably 2-4 hours.

[0031] In step 2), controlling the ratio of reactants and reaction conditions within the above range is beneficial to the reaction and more conducive to the substitution of chloromethyl groups, resulting in qualified chloromethylated cross-linked microspheres.

[0032] According to the preparation method of the present invention, preferably, in step 3), the chloromethylated cross-linked microspheres obtained in step 1) are swollen with C1-C5 alkyl alcohols. The weight ratio of C1-C5 alkyl alcohols to chloromethylated cross-linked microspheres can be (2-6):1, preferably (3-5):1.

[0033] In step 3), the swelling time of the chloromethylated cross-linked microspheres obtained in step 2) with C1-C5 alkyl alcohols can be 1-5 hours, preferably 1-3 hours.

[0034] In this invention, the C1-C5 alkyl alcohol can be a C1-C3 n-alkyl alcohol; preferably at least one of methanol and ethanol.

[0035] According to the preparation method of the present invention, preferably, the acid-binding agent is selected from at least one of triethylamine, anhydrous sodium carbonate, anhydrous potassium carbonate, and anhydrous sodium acetate; more preferably, it is selected from at least one of triethylamine and anhydrous sodium carbonate.

[0036] In this invention, the weight ratio of the acid-binding agent to the methylated cross-linked microspheres can be (0.05-0.5):1; preferably (0.1-0.3):1.

[0037] In this invention, the weight ratio of pyridine to chloromethylated crosslinked microspheres can be (3-6):1; preferably (3-5):1.

[0038] In step 3), the reaction temperature can be 50–90°C; preferably 60–80°C. The reaction time can be 8–24 h, preferably 10–20 h.

[0039] According to one embodiment of the present invention, the product can also be washed and dried after the reaction in step 3) is completed to obtain pyridine resin.

[0040] In step 3), washing can be performed using an aqueous solution of C1-C5 alkyl alcohols. The number of washes can be 1-5 times, preferably 3-4 times. Drying can be performed using any drying method known in the art; preferably, vacuum drying at 30-60°C for 1-5 hours.

[0041] The C1-C5 alkyl alcohols are C1-C3 n-alkyl alcohols; preferably, at least one of methanol and ethanol. The volume ratio of the C1-C5 alkyl alcohols to water can be 1:2 to 2:1; preferably 1:1.

[0042] In step 3), controlling the ratio of reaction raw materials and reaction conditions within the above range is beneficial to the reaction and more conducive to the pyridine functionalization of chloromethylated crosslinked microspheres, resulting in qualified pyridine resin.

[0043] In this invention, the water used in the preparation method can be deionized water or ultrapure water; preferably, it is deionized water.

[0044] On the other hand, the present invention also provides a pyridine resin prepared by the above preparation method.

[0045] The pyridine resin has a sphericity of at least 97%, preferably at least 97.2%. The pyridine resin has an adsorption rate of at least 95% for uranium in an acidic uranium-containing solution, preferably at least 99%.

[0046] Pyridine resins exhibit good uranium adsorption capacity when adsorbing uranium from acidic uranium-containing solutions.

[0047] In another aspect, the present invention also provides the use of the above-mentioned pyridine resin in removing uranium from acidic uranium-containing wastewater.

[0048] The acidic uranium-containing wastewater can be acidic uranium-containing industrial wastewater; preferably, it is acidic uranium-containing industrial wastewater with a pH value ≤ 5.

[0049] This invention successfully grafts pyridine functional groups onto a resin backbone using suspension polymerization and chemical modification methods to prepare a pyridine resin. This pyridine resin exhibits good wear resistance and mechanical properties, and demonstrates good adsorption performance for uranium in acidic uranium-containing wastewater. Attached Figure Description

[0050] Figure 1The infrared spectrum of the chloromethylated cross-linked microspheres and pyridine resin prepared in Example 1 of the present invention is shown; wherein, chlorospheres represent chloromethylated cross-linked microspheres. Detailed Implementation

[0051] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0052] <Testing Methods>

[0053] Uranium adsorption capacity test

[0054] 0.2 g of the prepared pyridine resin was used to conduct a static adsorption experiment in 100 mL of uranyl nitrate adsorption stock solution with a pH of 1 for 6 h. The concentration of uranyl ions in the stock adsorption solution and the concentration of uranyl ions in the adsorption tail liquid were measured.

[0055] The concentration of uranyl ions was determined in accordance with GB / T11225-1989.

[0056] Determination of the sphericity of the polished surface

[0057] Take 50g of the prepared pyridine resin and determine the sphericity of the resin according to GB / T 12598-2001.

[0058] Elemental analysis and characterization determination

[0059] The elemental analysis was performed using a Various EL / micro cube elemental analyzer manufactured by Elementar.

[0060] Infrared spectroscopy characterization determination

[0061] Using a Tensor II infrared spectrometer manufactured by Bruker GmbH, Germany, at wavenumbers of 4000–400 cm⁻¹ -1 Testing will be conducted within the specified range.

[0062] <Ingredient Description>

[0063] Unless otherwise specified, all raw materials used in the following examples are commercially available products.

[0064] Example 1

[0065] 1. Preparation of styrene-based copolymer crosslinked microspheres

[0066] Add 8g of polyvinyl alcohol to 400mL of deionized water and heat at 60℃ for 1h to completely dissolve the polyvinyl alcohol, thus obtaining a polyvinyl alcohol aqueous solution.

[0067] Take 34.92g of styrene, 5.08g of divinylbenzene, 0.6g of benzoyl peroxide, and 40g of petroleum ether, and mix them evenly to form the organic phase. Add the organic phase to the above-mentioned polyvinyl alcohol aqueous solution, stir to form beads, and then heat at 85℃ for 12 hours to carry out the curing reaction. After the reaction is completed, boil the reaction product in water at 100℃ for 2 hours, filter, and then dry the reaction product at 80℃ for 4 hours to obtain styrene skeleton copolymer crosslinked microspheres.

[0068] 2. Preparation of chloromethylated cross-linked microspheres

[0069] Take 20g of styrene-based copolymer crosslinked microspheres, add 100g of chloromethyl ether to fully swell for 2h, then add 8g of zinc chloride, and reflux the mixture at 50℃ for 16h. After the reaction is complete, wash the reaction product three times with methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, vacuum dry the reaction product at 50℃ for 3h to obtain chloromethylated crosslinked microspheres.

[0070] 3. Preparation of pyridine resin

[0071] 20g of chloromethylated crosslinked microspheres were added to 60g of anhydrous methanol and allowed to swell for 2 hours. Then, 60g of pyridine and 3g of triethylamine were added, and the mixture was stirred and heated at 80℃ for 14 hours to carry out the reaction. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain pyridine resin.

[0072] Example 2

[0073] 1. Preparation of styrene-based copolymer crosslinked microspheres

[0074] Add 8g of polyvinyl alcohol to 400mL of deionized water and heat at 60℃ for 1h to completely dissolve the polyvinyl alcohol, thus obtaining a polyvinyl alcohol aqueous solution.

[0075] Take 33.66g of styrene, 6.34g of divinylbenzene, 0.6g of benzoyl peroxide, and 40g of petroleum ether, and mix them evenly to form the organic phase. Add the organic phase to the above-mentioned polyvinyl alcohol aqueous solution, stir to form beads, and then heat at 85℃ for 12 hours to carry out the curing reaction. After the reaction is completed, boil the reaction product in water at 100℃ for 2 hours, filter, and dry the reaction product at 80℃ for 4 hours to obtain styrene skeleton copolymer crosslinked microspheres.

[0076] 2. Preparation of chloromethylated cross-linked microspheres

[0077] 20g of styrene-based copolymer crosslinked microspheres were added to 120g of chloromethyl ether and allowed to swell for 2 hours. Then, 10g of zinc chloride was added, and the mixture was stirred and heated at 50℃ for 24 hours under reflux. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain chloromethylated crosslinked microspheres.

[0078] 3. Preparation of pyridine resin

[0079] 20g of chloromethylated crosslinked microspheres were added to 60g of anhydrous methanol and allowed to swell for 2 hours. Then, 80g of pyridine and 4g of anhydrous sodium carbonate were added, and the mixture was stirred and heated at 80℃ for 18 hours to carry out the reaction. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain pyridine resin.

[0080] Comparative Example 1

[0081] 1. Preparation of styrene-based copolymer crosslinked microspheres

[0082] Add 1g of polyvinyl alcohol to 200mL of deionized water and heat at 60℃ for 1h to completely dissolve the polyvinyl alcohol, thus obtaining a polyvinyl alcohol aqueous solution.

[0083] 48.22 g of styrene, 5.07 g of divinylbenzene, 0.27 g of benzoyl peroxide, and 26.7 g of liquid paraffin were mixed evenly to form the organic phase. The organic phase was added to the above-mentioned polyvinyl alcohol aqueous solution, and after stirring to form beads, the mixture was heated at 85°C for 12 hours to carry out the curing reaction. After the reaction was completed, the reaction product was boiled in water at 100°C for 2 hours, filtered, and then dried at 80°C for 4 hours to obtain styrene-based copolymer crosslinked microspheres.

[0084] 2. Preparation of chloromethylated cross-linked microspheres

[0085] 20g of styrene-based copolymer crosslinked microspheres were added to 60g of chloromethyl ether and allowed to swell for 2 hours. Then, 4g of ferric chloride was added, and the mixture was stirred and heated at 50℃ for 12 hours under reflux. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain chloromethylated crosslinked microspheres.

[0086] 3. Preparation of pyridine resin

[0087] 20g of chloromethylated cross-linked microspheres were added to 60g of anhydrous ethanol and allowed to swell for 2 hours. Then, 40g of pyridine and 2g of anhydrous sodium carbonate were added, and the mixture was stirred and heated at 60℃ for 10 hours to carry out the reaction. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain pyridine resin.

[0088] Comparative Example 2

[0089] 1. Preparation of styrene-based copolymer crosslinked microspheres

[0090] Add 3g of polyvinyl alcohol to 300mL of deionized water and heat at 60℃ for 1h to completely dissolve the polyvinyl alcohol, thus obtaining a polyvinyl alcohol aqueous solution.

[0091] 46.53 g of styrene, 6.76 g of divinylbenzene, 0.53 g of azobisisobutyronitrile (AIBN), and 26.7 g of petroleum ether were mixed thoroughly to form the organic phase. This organic phase was added to the aforementioned polyvinyl alcohol aqueous solution, and after stirring to form beads, the mixture was heated at 85°C for 12 hours to allow for curing. After the reaction was complete, the reaction product was boiled in water at 100°C for 2 hours, filtered, and then dried at 80°C for 4 hours to obtain styrene-based copolymer crosslinked microspheres.

[0092] 2. Preparation of chloromethylated cross-linked microspheres

[0093] 20g of styrene-based copolymer crosslinked microspheres were added to 80g of chloromethyl ether and allowed to swell for 2 hours. Then, 6g of aluminum chloride was added, and the mixture was stirred and heated at 50℃ for 12 hours under reflux. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50℃ for 3 hours to obtain chloromethylated crosslinked microspheres.

[0094] 3. Preparation of pyridine resin

[0095] 20g of chloromethylated crosslinked microspheres were added to 60g of anhydrous methanol and allowed to swell for 2 hours. Then, 40g of pyridine and 2g of triethylamine were added, and the mixture was stirred and heated at 60°C for 10 hours to carry out the reaction. After the reaction was completed, the reaction product was washed three times with a methanol-water solution (methanol to deionized water volume ratio of 1:1). After washing, the reaction product was vacuum dried at 50°C for 3 hours to obtain pyridine resin.

[0096] Experimental Example 1

[0097] 0.2 g each of the styrene skeleton copolymer crosslinked microspheres, chloromethylated crosslinked microspheres and pyridine resin prepared in Example 1 were measured and elemental analysis was performed. The results are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] Table 1 shows that compared with styrene skeleton copolymer crosslinked microspheres, the C and H content of chloromethylated crosslinked microspheres is reduced, while the Cl content increases to 21.4 wt%, proving that the chloromethylation reaction proceeds normally. Compared with chloromethylated crosslinked microspheres, the N content of pyridine resin is significantly increased, proving that the pyridine group has been successfully grafted onto the resin.

[0102] 0.1 g each of the chloromethylated crosslinked microspheres and pyridine resin prepared in Example 1 were measured and directly subjected to infrared spectroscopy characterization without tableting. The results are as follows. Figure 1 As shown.

[0103] Depend on Figure 1 It can be seen that there is a significant difference between the two curves. In the infrared curve of pyridine resin, at a wavenumber of 1264 cm⁻¹... -1 With 670cm -1 The peak at 1360 cm⁻¹ has almost disappeared. -1 The presence of CN stretching vibrations indicates that pyridine underwent a substitution reaction with -Cl in the chloromethylated crosslinked microspheres (chlorospheres) to form pyridine resin.

[0104] Experiment Example 2

[0105] The sphericity of the pyridine resins prepared in Examples 1-2 and Comparative Examples 1-2 was determined by milling, and the results are shown in Table 2.

[0106] Table 2

[0107] serial number Spherical sphere ratio obtained from grinding (%) Example 1 97.4 Example 2 98.2 Comparative Example 1 93.7 Comparative Example 2 95.8

[0108] As shown in Table 2, the sphericity of the pyridine resin prepared in the examples is higher than that in the comparative examples, indicating that the pyridine resin prepared in the examples has better wear resistance and mechanical properties.

[0109] The pyridine resins prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to uranium adsorption capacity tests. Specific parameters and test results are shown in Table 3.

[0110] Table 3

[0111]

[0112]

[0113] As shown in Table 3, the pyridine resin prepared in the examples has a significantly higher adsorption capacity than that of the comparative example when adsorbing uranium ions in acidic uranium-containing solutions.

[0114] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A method for preparing a pyridine resin, comprising the following steps: 1) Styrene, divinylbenzene, initiator and porogen are mixed to form an organic phase. The organic phase is added to a dispersant solution and reacted at 50-95°C to obtain styrene skeleton copolymer crosslinked microspheres. The weight of divinylbenzene is 6-20 wt% of the total weight of styrene and divinylbenzene; the weight of the initiator is 0.1-2 wt% of the total weight of styrene and divinylbenzene; the weight ratio of the porogen to the total weight of styrene and divinylbenzene is (0.1-1):1; the weight ratio of the dispersant solution to the organic phase is (1-8):1; the porogen is selected from at least one of liquid paraffin and petroleum ether. The dispersant solution is an aqueous dispersant solution with a mass concentration of 0.2–5 wt%; the dispersant is selected from at least one of polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyethylene glycol, sodium dodecyl sulfate, carboxymethyl cellulose, and carboxypropyl methyl cellulose. 2) The styrene skeleton copolymer crosslinked microspheres obtained in step 1) are swollen with chloromethyl ether, wherein the weight ratio of chloromethyl ether to styrene skeleton copolymer crosslinked microspheres is (2-8):

1. Then, Lewis acid catalyst is added, and the reaction is carried out at 30-90°C to obtain chloromethylated crosslinked microspheres; wherein the weight ratio of Lewis acid catalyst to styrene skeleton copolymer crosslinked microspheres is (0.1-0.5):

1. 3) The chloromethylated cross-linked microspheres obtained in step 2) are swollen with at least one of methanol and ethanol, and then pyridine and an acid-binding agent are added. The mixture is reacted at 50-90°C to obtain pyridine resin. The weight ratio of pyridine to chloromethylated cross-linked microspheres is (3-6):1; the weight ratio of acid-binding agent to chloromethylated cross-linked microspheres is (0.05-0.5):1; the acid-binding agent is selected from at least one of triethylamine, anhydrous sodium carbonate, anhydrous potassium carbonate, and anhydrous sodium acetate.

2. The preparation method according to claim 1, characterized in that, In step 1), the initiator is selected from at least one of benzoyl peroxide and azobisisobutyronitrile.

3. The preparation method according to claim 1, characterized in that, In step 2), the Lewis acid catalyst is selected from at least one of FeCl3, TiCl4, ZnCl2, and AlCl3.

4. The preparation method according to claim 1, characterized in that: In step 1), the reaction time is 6–20 hours; In step 2), the reaction time is 8–36 hours; In step 3), the reaction time is 8 to 24 hours.

5. A pyridine resin prepared by the preparation method according to any one of claims 1 to 4, characterized in that, The pyridine resin has a sphericity of at least 97% and an adsorption rate of at least 95% for uranium in an acidic uranium-containing solution.

6. The use of the pyridine resin according to claim 5 in removing uranium from acidic uranium-containing wastewater.

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