A method for the stepwise preparation of an anti-aging modified nuclear grade adsorbent resin

Abstract

The present application relates to a kind of anti-aging modified nuclear grade adsorption resin step-by-step preparation method, comprising the following steps: step 1, pre-swelling treatment: chloromethylated polystyrene microspheres are placed in organic swelling reagent, and constant temperature pre-swelling is carried out;Step 2, anti-aging grafting: anti-aging agent and alkaline catalyst are added in swelling system, nucleophilic substitution reaction is carried out under nitrogen protection;After reaction, it is filtered, washed, dried, and anti-aging modified parent ball is prepared;Step 3, in situ adsorption functionalization: anti-aging modified parent ball is resuspended in deionized water phase, and metal salt precursor solution is added by batch feeding method, so that metal ions are complexed with residual benzyl chloride active site and diffuse to the interior of resin, then precipitant is added, and finished resin is prepared after filtration, washing, drying.The resin prepared by the present application realizes anti-aging modification on chloromethylated polystyrene microspheres, and simultaneously bonds inorganic functional crystal particle with selective adsorption.

Description

Technical Field

[0001] This invention relates to the technical field of stepwise preparation methods for nuclear-grade adsorption resins, specifically a stepwise preparation method for an anti-aging modified nuclear-grade adsorption resin. Background Technology

[0002] With the active and orderly development of the nuclear energy and nuclear fuel cycle industry, the safe and efficient treatment of radioactive wastewater has become a bottleneck restricting the sustainable development of nuclear energy and environmental protection. Large amounts of radioactive wastewater are inevitably generated during the treatment of radioactive liquids or the operation and maintenance of nuclear power plants. This wastewater contains highly active radionuclides, among which cesium-137 (Cs-137, half-life 30.17 years) and strontium-90 (Sr-90, half-life 28.8 years) are the main fission products. Because these two nuclides have extremely high solubility and biomigration in water, once they enter the ecosystem, they easily accumulate in organisms through the food chain, causing continuous internal radiation and disease hazards. Therefore, the selective and efficient removal of Cs-137 and Sr-90 from the wastewater, achieving downgrading and purification treatment, is of great strategic significance for ensuring environmental safety and reducing solid waste disposal costs.

[0003] Currently, adsorption separation is the most commonly used technology for treating radioactive wastewater due to its simple operation, high removal efficiency, and good economic benefits. However, actual radioactive waste liquids often have very complex operating conditions: The concentration of interfering ions is extremely high: the waste liquid is generally rich in high concentrations of non-radioactive group-one metal ions (such as sodium ions and potassium ions) and transition metal corrosion products (such as cobalt, nickel, and iron ions). Conventional ion exchange resins usually exhibit indiscriminate adsorption and have extremely poor selective adsorption capacity for trace amounts of radioactive cesium and strontium.

[0004] The extremely strong ionizing radiation environment: Radioactive waste liquids generate continuous and intense radiation (such as gamma rays) that bombards the polymer network of organic adsorption resins, causing irradiation degradation and producing a large number of destructive free radicals. This leads to the breaking of chemical bonds and rearrangement of molecular chains, macroscopically manifested as a sharp drop in resin strength, darkening of color, loss of functional groups, and shortened adsorption life. Frequent replacement of expired resins not only increases operating costs but also generates a large amount of highly induced radioactive waste resin secondary solid waste, placing even greater pressure on end-of-life disposal.

[0005] While inorganic ion exchange materials (such as ferrocyanides and polyvalent metal phosphates) possess good chemical and radiation stability and selectivity, their poor structural design, difficulty in molding, and brittleness under strong erosion easily clog industrial filtration pipelines and valves. Therefore, developing a "nuclear-grade adsorption resin" that combines the high selectivity of inorganic adsorbents with the toughness and moldability of organic polymers, while also exhibiting excellent radiation resistance, is a critical challenge urgently needing to be solved by the nuclear industry.

[0006] When modifying macroporous polystyrene-based resins for radiation resistance and adsorption functionalization, adding hindered amines (HALS) or phenols as anti-aging modifiers is an effective way to slow down radiation degradation. However, the grafting of anti-aging groups and the construction of selective adsorption active sites usually require the consumption of the same active benzyl chloride sites on the polymer backbone. How to synergistically regulate and achieve the dual optimization of "long lifetime (high radiation resistance)" and "high throughput (high selectivity)" on a limited number of active sites remains to be studied through systematic integrated synthetic pathways and mechanisms. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an anti-aging modified nuclear-grade adsorption resin and its preparation method, aiming to partially solve the aforementioned technical problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a stepwise preparation method for an anti-aging modified nuclear-grade adsorption resin, comprising the following steps: Step 1, Pre-swelling treatment: Chloromethylated polystyrene microspheres with an initial active benzyl chloride group content of 3.0 mmol / g to 5.5 mmol / g were placed in an organic swelling agent and pre-swelled at a constant temperature of 25℃ to 60℃ for 2 h to 12 h. Step 2, Anti-aging grafting: Add anti-aging agent and alkaline catalyst to the swelling system, and carry out nucleophilic substitution reaction under nitrogen protection at 50℃ to 90℃ for 4 h to 24 h; after the reaction, filter, wash and dry to obtain anti-aging modified mother ball; Step 3, In-situ Adsorption Functionalization: The anti-aging modified mother ball is resuspended in the deionized aqueous phase, and the metal salt precursor solution is added by batch feeding method, so that the metal ions complex with the residual benzyl chloride active sites and diffuse into the resin. Then, a precipitant is added, and the finished resin is obtained after filtration, washing and drying.

[0009] As a preferred technical solution, in step 2, the anti-aging agent is one of 4-amino-2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butyl-4-(hydroxymethyl)phenol, or a compound anti-aging agent of 2,2,6,6-tetramethyl-4-hydroxypiperidine alcohol and tris(2,4-di-tert-butylphenyl) phosphite.

[0010] As a preferred technical solution, in step 2, the molar ratio of the anti-aging agent to the initial active benzyl chloride group is 0.05:1 to 0.4:1.

[0011] As a preferred technical solution, the batch feeding method in step 3 is as follows: the metal salt precursor solution is slowly added in 3 to 6 batches, with each addition taking 5 to 10 minutes and the interval between each batch being 15 to 30 minutes.

[0012] As a preferred technical solution, the concentration of the metal salt precursor solution in step 3 is 0.05 mol / L to 0.5 mol / L.

[0013] As a preferred technical solution, in step 3, the metal ions in the metal salt precursor solution are magnesium ions, nickel ions, or zirconium ions, and the precipitant is potassium ferrocyanide or sodium phosphate or potassium phosphate.

[0014] As a preferred technical solution, the alkaline catalyst is anhydrous potassium carbonate, triethylamine, ethylenediamine, or sodium hydroxide.

[0015] As a preferred technical solution, the organic swelling agent in step 1 is dichloroethane or toluene.

[0016] As a preferred technical solution, the temperature for constant temperature pre-expansion in step 1 is 35°C to 50°C, and the time for constant temperature pre-expansion is 4 h to 8 h.

[0017] As a preferred technical solution, the reflux temperature in step 2 is 65°C to 80°C, and the nucleophilic substitution reaction time is 8 h to 16 h.

[0018] Compared with the prior art, the technical solution of this application has the following beneficial effects: (1) Integrated synergistic regulation of anti-aging and selective: This invention breaks through the technical limitations of traditional nuclear-grade resin anti-aging modification and adsorption modification being mutually exclusive and viciously competing for benzyl chloride sites. By stepwise regulating the feed ratio and mild reaction conditions, the non-destructive synergistic construction of "anti-aging groups" and "highly selective inorganic-organic hybrid adsorption centers" is achieved on the chloromethylated polystyrene microsphere framework.

[0019] (2) Radiation resistance stability: The anti-aging groups (such as hindered amine groups) introduced into the resin can act as "energy and free radical traps" to continuously capture free radicals such as carbon centers in the long-term, strong radiation radioactive wastewater environment. This allows the resin to maintain its adsorption capacity (capacity decay of less than 5%) after being subjected to strong gamma radiation of 1.0×105 Gy. The macroscopic mechanical strength and three-dimensional pore structure are intact, which greatly reduces the amount of radioactive solid waste generated and the material and labor costs of frequently replacing the resin.

[0020] (3) Selective capture and anti-loss capability: The transition metal ferrocyanides and polyvalent metal phosphates introduced by in-situ precipitation not only have a unique lattice cavity size that can perfectly match the hydration radius of Cs+ and Sr2+, but also form high bond energy chemical coordination. Under the background of extremely high concentration of high salt and acid-base interference ions, it can still achieve deep selective removal of trace nuclides, and the in-situ loaded crystals have a very strong binding force with the modified resin skeleton, so there is no risk of loss and pipe blockage under high-speed water flow. Attached Figure Description

[0021] Figure 1 A stepwise preparation method of an anti-aging modified nuclear-level adsorption resin provided by the present invention is shown in the schematic diagram. Figure 2 This invention provides a stepwise preparation method for an anti-aging modified nuclear-grade adsorption resin. Figure 1 ; Figure 3 This invention provides a stepwise preparation method for an anti-aging modified nuclear-grade adsorption resin. Figure 2 . Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0023] like Figure 1-3 The present invention provides a stepwise preparation method for an anti-aging modified nuclear-level adsorption resin, comprising the following steps: Step 1, Pre-swelling treatment: Chloromethylated polystyrene microspheres with an initial active benzyl chloride group content of 3.0 mmol / g to 5.5 mmol / g are placed in an organic swelling agent (such as dichloroethane, toluene, etc.) and pre-swelled at a constant temperature of 25℃ to 60℃ for 2 h to 12 h. This step aims to relax the tightly wound cross-linked polymer chains and fully expose the active benzyl chloride sites that were previously hidden deep within the pores and the framework.

[0024] Step 2, the first step of anti-aging grafting: An anti-aging agent and an alkaline catalyst (such as anhydrous potassium carbonate, triethylamine, ethylenediamine, or sodium hydroxide) are added to the swollen system. Under nitrogen protection, a nucleophilic substitution reaction is carried out under reflux at 50°C to 90°C for 4 to 24 hours. The molar ratio of the anti-aging agent to the initial active benzyl chloride group is 0.05:1 to 0.4:1, controlling the grafting rate of the anti-aging group to 10% to 35%. After the reaction, the mixture is filtered, repeatedly washed with ethanol / deionized water, and dried to obtain the anti-aging modified mother sphere. This step aims to construct a highly efficient radiation free radical protection network while precisely reserving sufficient and uniformly distributed reaction sites for subsequent functionalization.

[0025] Step 3, Second step in-situ adsorption functionalization: The anti-aging modified mother ball is resuspended in the deionized aqueous phase, and the metal salt precursor solution is added by batch feeding method, so that the metal ions and the residual benzyl chloride active sites can be complexed and diffused into the resin. More specifically, the transition metal ions or polyvalent metal ions can be fully complexed and uniformly diffused into the resin with the residual benzyl chloride active sites and the basic modified ligands (such as hindered amine secondary amine groups) on the surface.

[0026] Then, a precipitant (such as potassium ferrocyanide, phosphoric acid, or sodium phosphate) is added to allow inorganic functional crystals (such as Prussian blue analogues or zirconium phosphate) to crystallize and be loaded in situ on the pore walls of the resin's three-dimensional porous framework. After filtration, washing, and drying, the finished resin is obtained.

[0027] Preferably, the anti-aging agent in step 2 is selected from one of the following: 4-amino-2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butyl-4-(hydroxymethyl)phenol, or a compound anti-aging agent of 2,2,6,6-tetramethyl-4-hydroxypiperidine alcohol and tris(2,4-di-tert-butylphenyl)phosphite.

[0028] Preferably, the batch feeding method in step 3 specifically involves slowly adding the metal salt precursor solution in 3 to 6 batches, with each addition taking 5 to 10 minutes, and an interval of 15 to 30 minutes between each batch. This is to prevent the inorganic components from precipitating out as blocky deposits on the outside of the resin due to excessively high local concentrations, and to ensure that the inorganic functional crystals are uniformly and nanoscale anchored within the pores of the resin.

[0029] Preferably, the concentration of the metal salt precursor solution in step 3 is from 0.05 mol / L to 0.5 mol / L.

[0030] Preferably, in step 3, the metal ions in the metal salt precursor solution are magnesium ions, nickel ions, or zirconium ions, and the precipitant is potassium ferrocyanide or phosphate.

[0031] Preferably, the temperature for constant temperature pre-swelling in step 1 is 35°C to 50°C, and the time for constant temperature pre-swelling is 4 h to 8 h.

[0032] Preferably, the reflux temperature in step 2 is 65°C to 80°C, and the nucleophilic substitution reaction time is 8 h to 16 h.

[0033] To enable those skilled in the art to better understand the technical solution and implementation details of the present invention, detailed experimental demonstrations are provided below through specific embodiments and comparative examples. The chemical reagents and resin raw materials used in this invention are all commercially available.

[0034] Example 1: Preparation of potassium ferrocyanide modified nuclear-grade HALS-polystyrene adsorbent resin Step 1, Pre-swelling treatment: Weigh 20.0 g of commercially available chloromethylated polystyrene microspheres (benzyl chloride group content 4.8 mmol / g), place them in a three-necked flask, and add 150 mL of 1,2-dichloroethane as a swelling agent. Turn on the stirrer and let it stand in a 35℃ constant temperature water bath for 6 h to pre-swell, allowing the resin polymer backbone to expand and fully expose the active benzyl chloride reaction sites hidden in its internal pores.

[0035] Step 2, First step of anti-aging modification: 2.25 g of 4-amino-2,2,6,6-tetramethylpiperidine (TAD, with the molar ratio controlled at 15% of the initial total benzyl chloride groups) and 2.50 g of anhydrous potassium carbonate as an alkaline catalyst were added to the above pre-swelled system. The mixture was refluxed under nitrogen protection and reacted at 80℃ for 12 h. After the reaction, the system was cooled to room temperature, the resin was filtered out, washed three times with anhydrous ethanol, and then repeatedly washed with deionized water until the washing liquid was colorless and neutral. The resin was then dried in a vacuum drying oven at 60℃ for 12 h to obtain HALS covalently grafted anti-aging modified mother spheres. The nitrogen content was 1.82%, and the benzyl chloride group retention rate was 82%. The remaining benzyl chloride groups were additionally lost due to dialkylation and partial thermal decomposition.

[0036] Step 3, Second Step: In-situ Adsorption Functionalization (Loading of Potassium Ferrocyanide): The dried 15.0 g of the anti-aging modified mother spheres were resuspended in 150 mL of deionized water and slowly stirred at a constant temperature of 50 °C. A batch addition method was used: 50 mL of a 0.15 mol / L magnesium chloride (MgCl2) solution was prepared and added in four portions. The first addition was 12.5 mL, and the reaction was allowed to proceed for 20 min; subsequently, 12.5 mL was added dropwise every 20 min. After the addition was complete, stirring was continued at a constant temperature for 1.5 h to allow the MgCl2 to fully absorb the potassium chloride. 2+ Ions are evenly distributed within the resin channels through chelation and ion exchange.

[0037] Subsequently, 50 mL of a 0.15 mol / L potassium ferrocyanide (K4Fe(CN)6) solution was slowly added dropwise in batches, and the in-situ precipitation reaction was carried out at 50 °C for 3 h. After the reaction was completed, the mixture was filtered, thoroughly washed with warm water and anhydrous ethanol to remove residual free salts on the surface, and then vacuum dried at 55 °C for 15 h to obtain the finished anti-aging modified nuclear-grade adsorption resin.

[0038] Example 2: Preparation of nickel ferrocyanide modified nucleus-grade hindered phenol-polystyrene adsorbent resin Step 1, Pre-swelling treatment: Weigh 20.0 g of chloromethylated polystyrene microspheres (benzyl chloride group content of 4.2 mmol / g) and place them in a three-necked flask. Add 120 mL of dichloromethane and swell at 25 °C for 10 h to allow the molecular chains to stretch and the reaction sites to be exposed.

[0039] Step 2, First step of anti-aging modification: Add 1.98 g of 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (the molar ratio of the feed is controlled at 10% of the total initial benzyl chloride groups) and 1.50 g of sodium hydroxide alkaline catalyst, and react at 50℃ for 18 h. After the reaction is complete, filter out the modified mother ball, wash it alternately with deionized water and ethanol, and dry it under vacuum at 50℃ for 12 h to obtain hindered phenol covalently modified resin mother ball.

[0040] Step 3, Second Step: In-situ Adsorption Functionalization (Loading of Nickel Ferrocyanide): The obtained modified mother spheres were suspended in 120 mL of water and the temperature was adjusted to 60 °C. Using a batch feeding method, 40 mL of a 0.2 mol / L nickel nitrate (Ni(NO3)2) solution was slowly added dropwise in 5 batches (18 min intervals) over 1.5 h; then, 40 mL of a 0.2 mol / L potassium ferrocyanide (K4Fe(CN)6) solution was slowly added dropwise in 5 batches, and the reaction was stirred for 4 h to generate nano-sized nickel ferrocyanide crystals uniformly embedded in the pores of the resin. After filtration, washing, and vacuum drying, the finished adsorption resin was obtained.

[0041] Example 3: Preparation of zirconium phosphate modified nuclear-grade hindered amine / phosphite composite anti-aging polystyrene adsorbent resin Step 1, Pre-swelling treatment: Weigh 20.0 g of chloromethylated polystyrene microspheres (benzyl chloride group content of 4.5 mmol / g) and place them in 150 mL of chloroform solution. Swell at 45℃ for 5 h to allow the polymer chains to fully expand.

[0042] Step 2, First step of anti-aging modification: Add 1.40 g of a compound anti-aging system of 2,2,6,6-tetramethyl-4-hydroxypiperidinol and 0.90 g of tris(2,4-di-tert-butylphenyl) phosphite (total molar ratio of the compound feed is 12% of the initial benzyl chloride group) to the swelling solution, and add 2.2 g of triethylamine basic catalyst. Reflux at 75°C for 16 h. After completion, filter, thoroughly wash with deionized water and ethanol, and vacuum dry to obtain the compound anti-aging modified mother spheres.

[0043] Step 3, Second Step: In-situ Adsorption Functionalization (Loading of Nano-Zirconium Phosphate): The modified mother spheres were suspended in 150 mL of deionized water and the temperature was adjusted to 65 °C. Under slow stirring, 30 mL of 0.3 mol / L zirconium oxychloride (ZrOCl2) solution was added dropwise in three batches (30 min apart) to allow diffusion and chelation within the resin channels. Subsequently, 30 mL of 0.3 mol / L disodium hydrogen phosphate (Na2HPO4) solution was added dropwise to precipitate highly stable amorphous or microcrystalline zirconium phosphate (ZrP) in situ. After filtration, washing to neutrality, and vacuum drying, an adsorption resin with excellent radiation resistance and strontium removal capability was obtained.

[0044] Example 4: Preparation of nickel ferrocyanide modified nucleus-grade hindered phenol-polystyrene adsorbent resin This embodiment is the same as Embodiment 2 in terms of steps and raw materials, except that the molar ratio of the anti-aging agent is adjusted to the percentage of the total amount of the initial benzyl chloride groups, i.e., the molar ratio.

[0045] Step 1, Pre-swelling treatment: Weigh 20.0 g of chloromethylated polystyrene microspheres (benzyl chloride group content of 4.2 mmol / g) and place them in a three-necked flask. Add 120 mL of dichloromethane and swell at 25 °C for 10 h to allow the molecular chains to stretch and the reaction sites to be exposed.

[0046] Step 2, First step of anti-aging modification: Add 7.94 g of 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (the molar ratio of the feed is controlled at 40% of the total initial benzyl chloride groups) and 5.50 g of sodium hydroxide alkaline catalyst, and react at 50 °C for 18 h. After the reaction is complete, filter out the modified mother ball, wash it alternately with deionized water and ethanol, and dry it under vacuum at 50 °C for 12 h to obtain hindered phenol covalently modified resin mother ball.

[0047] Step 3, Second Step: In-situ Adsorption Functionalization (Loading of Nickel Ferrocyanide): The obtained modified mother spheres were suspended in 480 mL of water and the temperature was adjusted to 60 °C. Using a batch feeding method, 160 mL of 0.2 mol / L nickel nitrate (Ni(NO3)2) solution was slowly added dropwise in 5 batches (18 min intervals) over 1.5 h; then, 160 mL of 0.2 mol / L potassium ferrocyanide (K4Fe(CN)6) solution was slowly added dropwise in 5 batches, and the reaction was stirred for 4 h to generate nano-sized nickel ferrocyanide crystals uniformly embedded in the pores of the resin. After filtration, washing, and vacuum drying, the finished adsorption resin was obtained.

[0048] Comparative Example 1: Preparation of control resin without anti-aging modifier On the same chloromethylated polystyrene microspheres (benzyl chloride group content 4.8 mmol / g) framework, no first-step anti-aging modification reaction was performed. Instead, 20.0 g of the mother spheres were directly subjected to the same Mg treatment as in Example 1 after swelling. 2+ Complexation and in-situ precipitation of potassium ferrocyanide were used to obtain a hybrid adsorption resin without anti-aging agent loading, which was used for performance control experiments.

[0049] Comparative Example 2: Comparative resin prepared by simultaneous addition method without stepwise process 20.0 g of chloromethylated polystyrene microspheres were weighed and swollen in a swelling solution. Then, in a three-necked flask, the same proportions of 4-amino-2,2,6,6-tetramethylpiperidine as in Example 1 and the MgCl2 and K4Fe(CN)6 solutions required in the second step were added all at once, and the mixture was refluxed at 80°C. During the reaction, it was found that the hindered amine molecules and inorganic ions competed severely for reaction sites on the benzyl chloride groups, and the basic hindered amine readily caused a large-scale, transient, heterogeneous precipitation of inorganic metal salts on the outside of the resin bulk phase. After final washing and vacuum drying, the resulting resin had a surface covered with a large amount of uneven, blocky precipitate, internal pores with many vacancies, and extremely low specific surface area and ion exchange capacity.

[0050] Performance evaluation and testing methods To verify the application performance of the anti-aging modified nuclear-grade adsorption resin of this invention under actual working conditions and strong radiation, the following tests were conducted: Radiation resistance aging test: The dry resin samples prepared in Examples 1-3 and Comparative Examples 1-2 were placed under a Cobalt-60 gamma-ray irradiation source and bombarded with high-energy rays in a simulated radioactive waste environment (1.0 M sodium nitrate high-salt medium). The cumulative irradiation dose was set to 1.0 × 10⁻⁶. 5Gy. The sphere integrity rate of the resin before and after irradiation was observed by scanning electron microscopy, the degradation rate of anti-aging groups and functional ligands was determined by Fourier transform infrared spectroscopy, and the retention rate of single sphere compressive strength after irradiation was tested.

[0051] Test Result Comparison Table

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A stepwise preparation method for an anti-aging modified nuclear-grade adsorption resin, characterized in that, Includes the following steps: Step 1, Pre-swelling treatment: Chloromethylated polystyrene microspheres with an initial active benzyl chloride group content of 3.0 mmol / g to 5.5 mmol / g were placed in an organic swelling agent and pre-swelled at a constant temperature of 25℃ to 60℃ for 2 h to 12 h. Step 2, Anti-aging grafting: Add anti-aging agent and alkaline catalyst to the swelling system, and carry out nucleophilic substitution reaction under nitrogen protection at 50℃ to 90℃ for 4 h to 24 h; after the reaction, filter, wash and dry to obtain anti-aging modified mother ball; Step 3, In-situ Adsorption Functionalization: The anti-aging modified mother ball is resuspended in the deionized aqueous phase, and the metal salt precursor solution is added by batch feeding method, so that the metal ions complex with the residual benzyl chloride active sites and diffuse into the resin. Then, a precipitant is added, and the finished resin is obtained after filtration, washing and drying.

2. The preparation method according to claim 1, characterized in that, In step 2, the anti-aging agent is one of 4-amino-2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butyl-4-(hydroxymethyl)phenol, or a compound anti-aging agent of 2,2,6,6-tetramethyl-4-hydroxypiperidine alcohol and tris(2,4-di-tert-butylphenyl)phosphite.

3. The preparation method according to claim 1, characterized in that, In step 2, the molar ratio of the anti-aging agent to the initial active benzyl chloride group is 0.05:1 to 0.4:

1.

4. The preparation method according to claim 1, characterized in that, The batch feeding method described in step 3 is as follows: the metal salt precursor solution is slowly added in 3 to 6 batches, with each addition taking 5 to 10 minutes and the interval between each batch being 15 to 30 minutes.

5. The preparation method according to claim 1, characterized in that, The concentration of the metal salt precursor solution in step 3 is from 0.05 mol / L to 0.5 mol / L.

6. The preparation method according to claim 1, characterized in that, The metal ions in the metal salt precursor solution in step 3 are magnesium ions, nickel ions, or zirconium ions, and the precipitant is potassium ferrocyanide or sodium phosphate or potassium phosphate.

7. The preparation method according to claim 1, characterized in that, The alkaline catalyst is anhydrous potassium carbonate, triethylamine, ethylenediamine, or sodium hydroxide.

8. The preparation method according to claim 1, characterized in that, The organic swelling agent mentioned in step 1 is dichloroethane or toluene.

9. The preparation method according to claim 1, characterized in that, The temperature for the isothermal pre-expansion in step 1 is 35°C to 50°C, and the isothermal pre-expansion time is 4 h to 8 h.

10. The preparation method according to claim 1, characterized in that, The reflux temperature in step 2 is 65°C to 80°C, and the nucleophilic substitution reaction time is 8 h to 16 h.

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