Preparation method of resin for purifying heavy metal ions in wastewater

Abstract

The invention discloses a preparation method of resin for purifying heavy metal ions in wastewater, and belongs to the technical field of wastewater treatment.The preparation method comprises the steps that a polyvinyl alcohol aqueous solution and magnetic composite aerogel are mixed, sodium dodecyl sulfate, methylbenzene, divinyl benzene and benzoyl peroxide are added, vacuum drying is conducted after reaction, and the resin for purifying the heavy metal ions in the wastewater is obtained; the prepared resin for purifying the heavy metal ions in the wastewater has good purification capacity on the heavy metal ions and also has adsorption capacity on organic matters in the wastewater, and by preparing zirconium hydroxide / magnetic nanoparticles with magnetic nanoparticles as a core and zirconium hydroxide as a shell and utilizing Van der Waals force and hydrogen-bond interaction between the zirconium hydroxide and the organic matters, the heavy metal ions in the wastewater can be purified. The adsorption capacity of the resin on organic matters in wastewater is improved, and the resin has magnetism and can be recycled.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a preparation method of a resin for purifying heavy metal ions in wastewater. Background Art

[0002] In recent years, with the acceleration of the global industrialization process, the problem of heavy metal pollution has become increasingly prominent. Especially in the fields of wastewater treatment, mining and smelting, chemical industry, and electroplating, the emission of heavy metals has become one of the major challenges for global environmental protection. The produced wastewater usually needs to be filtered and purified by resin to meet the standards before being discharged. Polystyrene ion exchange resin is one of the most commonly used ion exchange resins at present, which has excellent properties such as good structural stability, recyclability, and easy surface modification, and is widely used in the field of wastewater treatment.

[0003] However, not only heavy metal ions exist in wastewater, but also toxic aromatic organic compounds often accompany them. Polystyrene ion exchange resin chelates with heavy metal cations in wastewater through functional groups, but its adsorption effect on organic compounds is only limited to the physical adsorption of porous resin, with low adsorption and purification efficiency, and it is difficult to elute, resulting in low reuse rate.

[0004] For example, the Chinese patent application with the publication number CN107043433A discloses a heavy metal wastewater treatment resin, its preparation method and application, which is a copolymer formed by two high molecular compounds, reacts with ammonia gas, and then uses chloroacetic acid to undergo a substitution reaction with amino groups to introduce carboxyl groups, improving the chelating ability with heavy metals and being reusable; however, this scheme has a low purification ability for wastewater containing organic pollutants.

[0005] For example, the Chinese patent application with the publication number CN115845555A discloses a method for treating volatile organic compounds using a super-high cross-linked adsorption resin, which is to prepare low cross-linked macroporous adsorption resin microspheres, and then perform chloromethylation and Friedel-Crafts post-cross-linking reactions on the microsphere matrix to obtain a resin with adsorption ability for organic compounds; however, this scheme uses a resin with a high cross-linking degree, and the effective contact area with wastewater in the wastewater is small. After macromolecular organic compounds occupy the adsorption sites, the adsorption ability for metal cations is weakened. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem of how to improve the purification ability of resin for organic compounds in wastewater, and to provide a preparation method of a resin for purifying heavy metal ions in wastewater.

[0007] The present invention prepares zirconium hydroxide / magnetic nanoparticles with magnetism, composites zirconium hydroxide / magnetic nanoparticles with carboxymethyl cellulose under the cross-linking action of citric acid, prepares a cellulose aerogel, and composites the cellulose aerogel with a resin to obtain a resin with a purification effect on heavy metal ions and organic substances.

[0008] The object of the present invention can be achieved by the following technical solutions: A preparation method of a resin for purifying heavy metal ions in wastewater, comprising the following steps:

[0009] In a reaction kettle, mix an aqueous solution of polyvinyl alcohol with a magnetic composite aerogel, dissolve sodium dodecyl sulfonate in deionized water and then add it to the reaction kettle, stir at 2000 - 2500 rpm for 2 - 3 min, then add toluene, divinylbenzene and benzoyl peroxide, heat up to 60 - 70 °C, stir at 50 - 60 rpm for 1 - 2 h, filter to obtain a polymer, wash it with hot water at 60 - 70 °C and then soak it in ethanol for 10 - 12 h, filter again and place it in a vacuum oven for vacuum drying at 40 - 50 °C for 20 - 24 h to obtain a resin for purifying heavy metal ions in wastewater.

[0010] Furthermore, the dosage ratio of the aqueous solution of polyvinyl alcohol, the magnetic composite aerogel, sodium dodecyl sulfonate, deionized water, toluene, divinylbenzene and benzoyl peroxide is 15 - 20 g : 1.5 - 2 g : 150 - 200 mg : 1 - 1.5 mL : 3 - 5 g : 1.5 - 2.5 g : 0.1 - 0.15 g; the mass fraction of the aqueous solution of polyvinyl alcohol is 10 - 15%.

[0011] Furthermore, the magnetic composite aerogel is prepared by the following steps:

[0012] In a reaction kettle, dissolve sodium carboxymethyl cellulose in deionized water, add citric acid to the reaction kettle, stir and react for 20 - 24 h, then add zirconium hydroxide / magnetic nanoparticles, ultrasonically disperse and then freeze-dry to obtain a cellulose aerogel, heat the cellulose aerogel in an oven to 120 - 140 °C for cross-linking reaction for 10 - 15 min to obtain a magnetic composite aerogel.

[0013] Furthermore, the dosage ratio of sodium carboxymethyl cellulose, deionized water, citric acid and zirconium hydroxide / magnetic nanoparticles is 3 - 5 g : 100 - 120 mL : 0.6 - 0.8 g : 0.5 - 1 g.

[0014] Furthermore, the zirconium hydroxide / magnetic nanoparticles are prepared by the following steps:

[0015] The magnetic nanoparticles were ultrasonically dispersed in an ethanol aqueous solution in a reaction kettle. Under stirring conditions, aqueous ammonia and an aqueous solution of zirconium nitrate dihydrate were added dropwise, and magnetically stirred at room temperature for 20 - 24 h. The precipitate was separated by magnetic separation, washed, and vacuum dried at 50 - 60 °C for 10 - 12 h to obtain zirconium hydroxide / magnetic nanoparticles.

[0016] Furthermore, the dosage ratio of the magnetic nanoparticles, ethanol aqueous solution, aqueous ammonia, and aqueous solution of zirconium nitrate dihydrate is 0.5 - 1 g : 50 - 60 mL : 1 - 2 mL : 5 - 8 mL.

[0017] Furthermore, the mass fraction of the ethanol aqueous solution is 90%, the mass fraction of the aqueous ammonia is 15 - 20%, and the mass fraction of the aqueous solution of zirconium nitrate dihydrate is 20%.

[0018] Furthermore, the magnetic nanoparticles were prepared by the following steps:

[0019] Ferric chloride hexahydrate and ferrous chloride tetrahydrate were dissolved in deionized water in a reaction kettle, heated to 70 - 80 °C, and 25 wt% aqueous ammonia was added dropwise until the pH reached 10. It was vigorously stirred for 2 - 2.5 h, the precipitate was separated by magnetic separation, washed, and vacuum dried at 50 - 60 °C for 10 - 12 h to obtain magnetic nanoparticles.

[0020] Furthermore, the dosage ratio of ferric chloride hexahydrate, ferrous chloride tetrahydrate, and deionized water is 2 - 3 g : 1 - 1.5 g : 45 - 50 mL.

[0021] Advantages of the present invention:

[0022] (1) The resin for purifying heavy metal ions in wastewater prepared by the present invention has good purification ability for heavy metal ions, and also has adsorption ability for organic matters in wastewater. By preparing zirconium hydroxide / magnetic nanoparticles with magnetic nanoparticles as the core and zirconium hydroxide as the shell, the van der Waals force and hydrogen bond interaction between zirconium hydroxide and organic matters are utilized to improve the adsorption ability of the resin for organic matters in wastewater, and it has magnetism and can be recycled.

[0023] (2) The preparation method of the present invention is crosslinked and modified with citric acid and carboxymethyl cellulose and then compounded with magnetic zirconium hydroxide / magnetic nanoparticles. By utilizing the combination of zirconium hydroxide and citric acid groups, a cellulose aerogel is prepared after freeze-drying, and the zirconium hydroxide / magnetic nanoparticles are compounded with the cellulose aerogel. Under the action of high temperature, not only the crosslinking strength of citric acid and carboxymethyl cellulose is improved, but also the carboxymethyl cellulose crosslinked by citric acid is firmly compounded and fixed with the zirconium hydroxide / magnetic nanoparticles. After the carboxymethyl cellulose adsorbs metal cations, it can be separated by magnetic separation along with the zirconium hydroxide / magnetic nanoparticles, improving the heavy metal ion purification ability of the resin. Detailed implementation mode

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Embodiment 1: A preparation method of a resin for purifying heavy metal ions in wastewater, comprising the following steps:

[0026] S1. Dissolve 2.5 g of ferric chloride hexahydrate and 2 g of ferrous chloride tetrahydrate in 45 mL of deionized water in a reaction kettle, heat up to 75 °C, dropwise add 15 wt% ammonia water until the pH value reaches 10, stir for 2.5 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 12 h to obtain magnetic nanoparticles.

[0027] S2. Ultrasonically disperse 1.5 g of magnetic nanoparticles in 55 mL of 90 wt% ethanol aqueous solution in a reaction kettle, dropwise add 2 mL of 17.5 wt% ammonia water and 7 mL of 20 wt% zirconium nitrate dihydrate aqueous solution under stirring, magnetically stir at room temperature for 22 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 10 h to obtain zirconium hydroxide / magnetic nanoparticles.

[0028] S3. Dissolve 4 g of sodium carboxymethyl cellulose in 110 mL of deionized water in a reaction kettle, add 0.7 g of citric acid, stir and react for 24 h, then add 0.6 g of zirconium hydroxide / magnetic nanoparticles, ultrasonically disperse and freeze-dry to obtain cellulose aerogel, heat the cellulose aerogel in an oven to 130 °C for cross-linking reaction for 15 min to obtain magnetic composite aerogel.

[0029] S4. Mix 17 g of 10 wt% polyvinyl alcohol aqueous solution with 1.8 g of magnetic composite aerogel in a reaction kettle, add 3 mL of sodium dodecyl sulfonate dissolved in 0.8 mL of deionized water, stir for 2 min, add 4 g of toluene, 2 g of divinylbenzene and 0.15 g of benzoyl peroxide, heat up to 65 °C, stir for 1 h, filter to obtain a polymer, wash with 60 °C hot water and soak in ethanol for 12 h, filter again and place in a vacuum oven for vacuum drying at 45 °C for 24 h to obtain a resin for purifying heavy metal ions in wastewater.

[0030] Embodiment 2: A preparation method of a resin for purifying heavy metal ions in wastewater, comprising the following steps:

[0031] S1. Dissolve 3 g of ferric chloride hexahydrate and 2 g of ferrous chloride tetrahydrate in 45 mL of deionized water in a reaction kettle, heat up to 75 °C, dropwise add 25 wt% ammonia water until the pH value reaches 10, stir for 2.5 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 12 h to obtain magnetic nanoparticles.

[0032] S2. Ultrasonically disperse 1 g of magnetic nanoparticles in 50 mL of 90 wt% ethanol aqueous solution in a reaction kettle, dropwise add 2 mL of 15 wt% ammonia water and 5 mL of 20 wt% zirconium nitrate dihydrate aqueous solution under stirring conditions, magnetically stir at room temperature for 20 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 10 h to obtain zirconium hydroxide / magnetic nanoparticles.

[0033] S3. Dissolve 3 g of sodium carboxymethyl cellulose in 100 mL of deionized water in a reaction kettle, add 0.8 g of citric acid, stir and react for 24 h, then add 0.7 g of zirconium hydroxide / magnetic nanoparticles, ultrasonically disperse and freeze-dry to obtain cellulose aerogel, heat the cellulose aerogel in an oven to 120 °C for cross-linking reaction for 10 min to obtain magnetic composite aerogel.

[0034] S4. Mix 15 g of 12.5 wt% polyvinyl alcohol aqueous solution with 1.5 g of magnetic composite aerogel in a reaction kettle, add 2 mL of sodium dodecyl sulfonate dissolved in 0.8 mL of deionized water, stir for 2 min, add 3 g of toluene, 2 g of divinylbenzene and 0.1 g of benzoyl peroxide, heat up to 65 °C, stir for 1 h, filter to obtain the polymer, wash with 60 °C hot water and soak in ethanol for 12 h, filter again and place in a vacuum oven for vacuum drying at 45 °C for 24 h to obtain the resin for purifying heavy metal ions in wastewater.

[0035] Example 3: A preparation method of a resin for purifying heavy metal ions in wastewater, comprising the following steps:

[0036] S1. Dissolve 2 g of ferric chloride hexahydrate and 3 g of ferrous chloride tetrahydrate in 45 mL of deionized water in a reaction kettle, heat up to 75 °C, dropwise add 25 wt% ammonia water until the pH value reaches 10, stir for 2.5 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 12 h to obtain magnetic nanoparticles.

[0037] S2. Ultrasonically disperse 2 g of magnetic nanoparticles in 50 mL of 90 wt% ethanol aqueous solution in a reaction kettle, dropwise add 2 mL of 17.5 wt% ammonia water and 7 mL of 20 wt% zirconium nitrate dihydrate aqueous solution under stirring conditions, magnetically stir at room temperature for 22 h, magnetically separate the precipitate, wash the precipitate with deionized water and ethanol, and vacuum dry at 50 °C for 10 h to obtain zirconium hydroxide / magnetic nanoparticles.

[0038] S3. Dissolve 4 g of sodium carboxymethyl cellulose in 110 mL of deionized water in a reaction kettle, add 0.8 g of citric acid, stir and react for 24 h, then add 0.6 g of zirconium hydroxide / magnetic nanoparticles, ultrasonically disperse and freeze-dry to obtain cellulose aerogel. Heat the cellulose aerogel in an oven to 130 °C for cross-linking reaction for 15 min to obtain magnetic composite aerogel.

[0039] S4. Mix 17 g of 15 wt% polyvinyl alcohol aqueous solution with 1.8 g of magnetic composite aerogel in a reaction kettle, add 3 mL of sodium dodecyl sulfonate dissolved in 0.8 mL of deionized water, stir for 2 min, add 4 g of toluene, 2 g of divinylbenzene and 0.15 g of benzoyl peroxide, heat up to 65 °C, stir for 1 h, filter to obtain the polymer, wash with 60 °C hot water and soak in ethanol for 12 h, filter again and place in a vacuum oven at 45 °C for vacuum drying for 24 h to obtain the resin for purifying heavy metal ions in wastewater.

[0040] Principle of the invention:

[0041] In the present invention, magnetic nanoparticles are synthesized, and zirconium hydroxide is in-situ generated on the surface of the magnetic nanoparticles to form zirconium hydroxide / magnetic nanoparticles with magnetic nanoparticles as the core and zirconium hydroxide as the shell. Zirconium hydroxide can adsorb organic compounds in saline solution through van der Waals force and hydrogen bond in wastewater, improving the removal ability of the resin for organic pollutants in wastewater. The magnetic nanoparticles have the effect of enhancing catalytic binding sites, which helps to improve the catalytic binding effect on heavy metal ions and enhance the heavy metal chelating ability. The magnetic nanoparticles catalyzed by ammonia water and the zirconium hydroxide formed by common ammonia water have good binding uniformity and high binding strength, and the surface contains basic functional groups.

[0042] Carboxymethyl cellulose can be used as an adsorbent for heavy metal ions. It contains hydroxyl groups and carboxymethyl groups, which have a binding effect on metal cations. However, nano-scale carboxymethyl cellulose is easily soluble in water, and it is difficult to separate from wastewater after binding metal cations. In the present invention, carboxymethyl cellulose is cross-linked and modified with citric acid and then compounded with magnetic zirconium hydroxide / magnetic nanoparticles. By using the combination of zirconium hydroxide and citric acid groups, cellulose aerogel is prepared after freeze-drying, and zirconium hydroxide / magnetic nanoparticles are compounded with cellulose aerogel. Under the action of high temperature, not only the cross-linking strength of citric acid and carboxymethyl cellulose is improved, but also the carboxymethyl cellulose cross-linked by citric acid is firmly compounded and fixed with zirconium hydroxide / magnetic nanoparticles. After carboxymethyl cellulose adsorbs metal cations, it can be separated by magnetic separation with zirconium hydroxide / magnetic nanoparticles, improving the heavy metal ion purification ability of the resin.

[0043] Due to the too low density of aerogel, it is not easy to settle in wastewater, resulting in insufficient contact with heavy metal ions and organic pollutants and affecting the purification ability. In the present invention, zirconium hydroxide / magnetic nanoparticles are compounded with cellulose aerogel to increase the density of cellulose aerogel and improve the settling ability of cellulose aerogel in wastewater; cellulose aerogel and polyvinyl alcohol are uniformly compounded under the action of surfactant sodium dodecyl sulfonate, and then, by using the stabilizing effect of polyvinyl alcohol in the preparation of polystyrene resin, cellulose aerogel and polystyrene resin are uniformly compounded to improve the purification ability of polystyrene resin for heavy metal ions and organic pollutants. The magnetic zirconium hydroxide / magnetic nanoparticles can also be recycled and reused, with high economic value.

[0044] Comparative Example 1: The difference from Example 1 is that in S3, zirconium hydroxide is used to replace zirconium hydroxide / magnetic nanoparticles to prepare a resin for purifying heavy metal ions in wastewater.

[0045] Comparative Example 2: The difference from Example 1 is that in S4, zirconium hydroxide / magnetic nanoparticles are used to replace the magnetic composite aerogel to prepare a resin for purifying heavy metal ions in wastewater.

[0046] Comparative Example 3: The difference from Example 1 is that in S3, citric acid is not added to prepare a resin for purifying heavy metal ions in wastewater.

[0047] Performance tests were carried out on the resins for purifying heavy metal ions in wastewater prepared in Examples 1 - 3 and Comparative Examples 1 - 3. The resins for purifying heavy metal ions in wastewater were swollen in ethanol and then filtered and rinsed with deionized water by suction filtration. After replacing ethanol with deionized water, the resins were obtained. 5 mL of the resins were weighed and filled into a resin column (Φ36 mm * 550 mm). 100 mL of wastewater was prepared, with the phenol concentration in the wastewater being 6 g / L, the concentrations of copper ions, lead ions, and cadmium ions all being 100 mg / L, and the total heavy metal concentration being 300 mg / L. The pH value of the wastewater was adjusted to 5, and the wastewater was passed through the resin column at a flow rate of 3 mL / min. The concentrations of phenol, copper ions, lead ions, and cadmium ions in the water were detected, and the purification rates of heavy metal ions and organic matters were calculated; the resins for purifying heavy metal ions in wastewater were eluted with 2M nitric acid solution, the phenol content and heavy metal ion content in the eluate were detected, and the elution rate was calculated. The results are shown in Table 1:

[0048] Table 1: Test results of the wastewater treatment performance of the resins for purifying heavy metal ions in wastewater

[0049] Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Heavy metal ion purification rate (%) 99.83 99.87 99.88 96.34 93.42 97.73 Organic matter purification rate (%) 98.52 98.58 98.61 94.21 72.17 96.25 Heavy metal ion elution rate (%) 98.41 98.54 98.57 97.62 96.45 97.91 Organic matter elution rate (%) 97.23 97.33 97.37 96.51 96.13 96.34

[0050] As can be seen from Table 1, the resin for purifying heavy metal ions in wastewater prepared by the present invention has high purification efficiency and high elution rate for heavy metal ions, indicating good recyclability. Moreover, it also has an adsorption and removal effect on organic matters and good purification ability for metal wastewater containing organic matters.

[0051] In Comparative Example 1, since zirconium hydroxide was not compounded with magnetic nanoparticles to form a core-shell structure, the specific surface area decreased, and the catalytic effect of magnetic nanoparticles on binding sites was lacking, resulting in lower purification rates of heavy metal ions and organic matters.

[0052] In Comparative Example 2, due to the absence of the composite aerogel, the adsorption ability of the resin for organic matters was greatly reduced, and the purification rate of organic matters was significantly decreased. Moreover, the adsorption of organic matters occupied the adsorption sites of the resin, reducing the purification rate of heavy metal ions.

[0053] In Comparative Example 3, due to the absence of citric acid, the degree of compounding of carboxymethyl cellulose with zirconium hydroxide / magnetic nanoparticles was low, and the binding strength was low. Zirconium hydroxide / magnetic nanoparticles were prone to detach from the aerogel during the preparation of the resin, reducing the synergistic effect on the adsorption of organic matters and resulting in a decrease in the purification rate of organic matters.

[0054] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a resin for purifying heavy metal ions in wastewater, characterized in that: The steps include: In a reaction kettle, a polyvinyl alcohol aqueous solution is mixed with a magnetic composite aerogel, sodium dodecyl sulfate is dissolved in deionized water and added into the reaction kettle, stirred for 2-3 minutes, then toluene, divinylbenzene and benzoyl peroxide are added, the temperature is raised to 60-70°C, stirred at a speed of 50-60rpm for 1-2 hours, filtered to obtain a polymer, washed with 60-70°C hot water, immersed in ethanol for 10-12 hours, filtered again, and placed in a vacuum oven at 40-50°C for vacuum drying for 20-24 hours to obtain a resin for purifying heavy metal ions in wastewater.

2. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 1, characterized in that: The dosage ratio of the polyvinyl alcohol aqueous solution, magnetic composite aerogel, sodium dodecyl sulfonate, deionized water, toluene, divinylbenzene and benzoyl peroxide is 15-20g: 1.5-2g: 150-200mg: 1-1.5mL: 3-5g: 1.5-2.5g: 0.1-0.15g; the mass fraction of the polyvinyl alcohol aqueous solution is 10-15%.

3. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 2, characterized in that: The magnetic composite aerogel is prepared by the following steps: Sodium carboxymethyl cellulose was dissolved in deionized water in a reactor, citric acid was added into the reactor, stirred for 20-24 hours, and then zirconium hydroxide / magnetic nanoparticles were added, and cellulose aerogel was obtained by freeze-drying after ultrasonic dispersion. The cellulose aerogel was heated to 120-140° C. in an oven for cross-linking reaction for 10-15 minutes to obtain a magnetic composite aerogel.

4. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 3, characterized in that: The dosage ratio of the sodium carboxymethyl cellulose, deionized water, citric acid and zirconium hydroxide / magnetic nanoparticles is 3-5 g: 100-120 mL: 0.6-0.8 g: 0.5-1 g.

5. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 4, characterized in that: The zirconium hydroxide / magnetic nanoparticles are prepared by the following steps: The magnetic nanoparticles are ultrasonically dispersed in an ethanol aqueous solution in a reaction kettle, and ammonia water and a zirconium nitrate dihydrate aqueous solution are added dropwise under stirring. The mixture is magnetically stirred at room temperature for 20-24 hours, the precipitate is magnetically separated, the precipitate is washed, and vacuum dried at 50-60° C. for 10-12 hours to obtain zirconium hydroxide / magnetic nanoparticles.

6. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 5, characterized in that: The usage ratio of the magnetic nanoparticles, the ethanol aqueous solution, the ammonia water and the zirconium nitrate dihydrate aqueous solution is 0.5-1 g: 50-60 mL: 1-2 mL: 5-8 mL.

7. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 6, characterized in that: The mass fraction of the ethanol aqueous solution is 90%, the mass fraction of the ammonia water is 15-20%, and the mass fraction of the zirconium nitrate dihydrate aqueous solution is 20%.

8. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 6, characterized in that: The magnetic nanoparticles are prepared by the following steps: Dissolve ferric chloride hexahydrate and ferrous chloride tetrahydrate in deionized water in a reaction kettle, heat to 70-80°C, add ammonia water dropwise until the pH value reaches 10, stir vigorously for 2-2.5 hours, separate the precipitate by magnetic force, wash the precipitate, and vacuum dry at 50-60°C for 10-12 hours to obtain magnetic nanoparticles.

9. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 8, characterized in that: The usage ratio of the ferric chloride hexahydrate, ferrous chloride tetrahydrate and deionized water is 2-3 g: 1-1.5 g: 45-50 mL.

10. The method for preparing a resin for purifying heavy metal ions in wastewater according to claim 8, characterized in that: The mass fraction of the ammonia water is 25%.