Method for preparing metal ion adsorbent from waste rock wool and application of the metal ion adsorbent in adsorption treatment of heavy metal wastewater

Abstract

The application discloses a method for preparing a metal ion adsorbent from waste rock wool and application of the metal ion adsorbent in adsorption treatment of heavy metal wastewater. First, the rock wool is treated at high temperature and acidification, the rock wool is soaked in a polyethyleneimine-polyethylene glycol dispersion liquid, the rock wool dispersion liquid is freeze-dried to prepare a porous material, the porous material is used to adsorb acrylic acid, epoxy propyl acrylate and an initiator, and then a polymerization reaction is initiated by heating, and the heavy metal ion adsorbent is obtained after washing and drying. The adsorbent uses waste rock wool as raw material, has low cost, high chemical stability, excellent adsorption performance on various heavy metal ions, and presents a block shape and is easy to recycle. The method can simultaneously solve the environmental problems caused by waste rock wool and heavy metal ions, and turns waste into treasure and achieves two goals at one time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heavy metal wastewater treatment, and particularly relates to a method for preparing a metal ion adsorbent from waste rock wool and application of the metal ion adsorbent in adsorption treatment of heavy metal wastewater. BACKGROUND

[0002] Due to the rapid development of industrialization in China, a large amount of heavy metal-containing wastewater is produced. These high-concentration heavy metal-containing wastewater is directly or indirectly discharged into the ecological environment. Since heavy metal ions are non-biodegradable, they accumulate in the ecological system through the food chain or drinking water, causing great harm to the ecological system and human health. When the intake of heavy metals in the human body exceeds the standard, various diseases or symptoms will be caused, such as nervous disorder, joint pain, and even kidney disease, cancer, etc.

[0003] Both physical and chemical methods can remove heavy metal ions in water, such as reverse osmosis, ion exchange, electrochemical precipitation, filtration, advanced oxidation, biological treatment and adsorption, etc. Among all the above methods, adsorption is usually the first choice for heavy metal ion removal because of its strong universality, high efficiency, easy handling, reversibility, etc. Since people realized that adsorption is one of the most convenient wastewater treatment methods, researchers have been focusing on developing cheap, effective, environmentally friendly and reusable adsorbents.

[0004] Rock wool is widely used in building exterior wall insulation due to its high chemical stability, non-flammability, low cost and other excellent properties. However, with the demolition of aging buildings, a large amount of waste rock wool is produced, which is directly dumped or buried in most cases, causing serious environmental pollution due to its difficulty in biodegradation. In recent years, developing waste rock wool into advanced functional materials has become a more attractive way to solve the problem of recycling. Due to the characteristics of high specific surface area, rock wool has certain advantages as an adsorbent substrate.

[0005] Polyethyleneimine (PEI) is a water-soluble organic base. Due to the rich amine groups in its structure, it has excellent chelating ability and has been widely used as a modifier to improve the adsorption performance. CN114887598B discloses a preparation method and application of a polyethyleneimine modified Fe3O4 magnetic adsorbent. The method first modifies Fe3O4 magnetic nanoparticles with a mercapto group, and then reacts with mercapto polyethyleneimine to obtain a polyethyleneimine modified Fe3O4 magnetic adsorbent connected by a disulfide bond. However, the chemical stability of magnetic Fe3O4 under strong acidic or alkaline conditions is low, which limits its application prospect in wastewater adsorption treatment. CN104624178A discloses a preparation method of a heavy metal ion adsorbent using polyethyleneimine modified sodium lignosulfonate. The method uses electrostatic or chemical cross-linking method to connect polyethyleneimine to sodium lignosulfonate, and prepares a stable polyethyleneimine-sodium lignosulfonate heavy metal ion adsorbent. However, the adsorbent prepared by this method is in powder form, which is slow to settle in water and difficult to recover, which is not convenient for actual use.

[0006] Therefore, it is urgent to seek a heavy metal adsorbent with simple preparation process, low cost, high chemical stability, easy recovery and reasonable utilization of rock wool waste. SUMMARY

[0007] In view of the above problems existing in the prior art, the present application provides a method for preparing a metal ion adsorbent from waste rock wool and its application in heavy metal wastewater adsorption treatment. The present application mainly uses waste rock wool as raw material, which is low in cost and realizes the value-added utilization of waste materials. The heavy metal adsorbent prepared by the present application is a blocky porous material, which is not easy to lose in water, easy to recover, high in chemical stability, convenient to use and has excellent adsorption effect on various heavy metal ions.

[0008] The method for preparing a metal ion adsorbent from waste rock wool of the present application comprises the following steps:

[0009] Step 1: heat the waste rock wool in a muffle furnace at high temperature for a period of time, and then soak it in a hydrochloric acid solution after cooling to obtain acidified rock wool;

[0010] Step 2: wash, filter and dry the acidified rock wool, mix it with a polyethyleneimine and polyethylene glycol solution and stir for a period of time to obtain a rock wool dispersion;

[0011] Step 3: freeze-dry the rock wool dispersion to obtain modified rock wool;

[0012] Step 4: immerse the modified rock wool in an aqueous solution containing ammonium persulfate initiator, acrylic monomer and epoxypropyl acrylate monomer for a period of time, then take it out and heat the rock wool to initiate polymerization;

[0013] Step 5: The rock wool material is washed with deionized water to remove polyethylene glycol, and after drying, a porous polyethyleneimine-polyacrylic acid modified waste rock wool based heavy metal adsorbent is obtained.

[0014] In step 1, the temperature of the muffle furnace high-temperature heating is set to 425 DEG C, and the treatment time is 25 min. The initial temperature is 25 DEG C, and the temperature rising speed is 16 DEG C / min.

[0015] In step 1, the concentration of the hydrochloric acid solution is 2.5 mol / L, and the acid treatment time is 12 min.

[0016] In step 2, the mass ratio of the acidified rock wool to polyethyleneimine is 1:7.2, the mass ratio of the polyethylene glycol to polyethyleneimine is 1:3.6, and the solid-liquid mass volume ratio of the polyethyleneimine to the aqueous solution is 1.2 g:10 mL.

[0017] In step 3, the freeze-drying temperature is -55 DEG C, and the freeze-drying time is 32 h.

[0018] In step 4, the acrylic monomer is selected from acrylic acid and methacrylic acid; the propylene glycol acrylate monomer is selected from propylene glycol acrylate and methacrylic acid propylene glycol acrylate; and the mass ratio among ammonium persulfate, the acrylic monomer and the propylene glycol acrylate monomer is 0.1:5:5, wherein the concentration of ammonium persulfate in water is 0.05 mol / L.

[0019] In step 4, the polymerization temperature is 80 DEG C, and the polymerization time is 3 h.

[0020] The metal ion adsorbent of the application is applied to the adsorption treatment of heavy metal wastewater, and the system pH is 2-7, preferably pH is 4-7, and the optimal pH is 6. When the pH is 6, the adsorption capacity of the metal ion adsorbent to Cd 6+ , Cu 2+ , Pb 2+ and other heavy metal ions is close to 1000 mg / g, and the metal ion adsorbent has good practicability.

[0021] The beneficial effects of the application are as follows:

[0022] 1. The application mainly uses waste rock wool and polyethyleneimine as raw materials, realizes the value-added utilization of waste materials at low cost, solves the environmental pollution problem of waste rock wool, and is economic and environmentally friendly.

[0023] 2. The heavy metal adsorbent prepared by the application is a blocky porous material, is not easy to flow away in water, is easy to recycle and has high chemical stability, and is convenient to use. The waste rock wool based heavy metal adsorbent obtained by the method has the adsorption capacity of 1000 mg / g to Cd 6+ , Cu 2+ , Pb 2+The adsorption amount of various heavy metal ions is close to 1000 mg / g, and the adsorption amount is close to 1000 mg / g, and the adsorption amount is close to 1000 mg / g. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The adsorption amount of the waste rock wool-based heavy metal adsorbent prepared in the embodiment of the application under different pH conditions on Cd 6+ , Cu 2 + , Pb 2+ .

[0025] Figure 2 The adsorption amount of the waste rock wool-based heavy metal adsorbent prepared in the embodiment of the application under different time conditions on Pb 2+ .

[0026] Figure 3 The removal rate and adsorption amount of the waste rock wool-based heavy metal adsorbent prepared in the embodiment of the application under different initial concentration conditions on Pb 2+ . DETAILED DESCRIPTION

[0027] In order to make the technical problems to be solved by the application, the technical solutions and beneficial effects more clear and explicit, the application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0028] Embodiment 1:

[0029] 1. Place the waste rock wool in a muffle furnace for high temperature treatment, set the muffle furnace temperature to 425℃, the initial temperature is 25℃, the temperature rising speed is 16℃ / min, and the high temperature treatment time is 25min, to remove the colloid on the surface of the rock wool; after the rock wool is cooled, immerse the rock wool in a 2.5mol / L hydrochloric acid solution, and the acid treatment time is 12min, to expose the hydroxyl groups of the rock wool, and obtain acidified rock wool;

[0030] 2. After washing, filtering and drying the acidified rock wool, mix and stir the acidified rock wool with a polyethyleneimine solution and a polyethylene glycol solution for a period of time, wherein the mass ratio between the acidified rock wool and the polyethyleneimine is 1:7.2, the solid-liquid mass volume ratio of the polyethyleneimine and the aqueous solution is 1.2g:10mL, and the mass ratio between the polyethylene glycol and the polyethyleneimine is 1:3.6;

[0031] 3. Treat the rock wool dispersion liquid by freeze-drying method, the freeze-drying temperature is-55℃, and the freeze-drying time is 32h, to obtain polyethyleneimine modified rock wool;

[0032] 4. Immersing the polyethyleneimine modified rock wool in an aqueous solution containing ammonium persulfate initiator, acrylic monomer and acrylic glycidyl acrylate monomer for a period of time, wherein the acrylic monomer and the acrylic glycidyl acrylate monomer include acrylic acid, methacrylic acid, acrylic glycidyl acrylate, methacrylic glycidyl acrylate and combinations thereof, the mass ratio among the ammonium persulfate, the acrylic monomer and the acrylic glycidyl acrylate monomer is 0.1:5:5, and the concentration of the ammonium persulfate in the water is 0.05 mol / L; then taking out the rock wool; and then heating the rock wool to initiate a polymerization reaction, wherein the polymerization temperature is 80°C and the polymerization time is 3 h;

[0033] 5. Washing the rock wool material with deionized water to remove the polyethylene glycol, and drying to obtain the polyethyleneimine-polyacrylic acid modified waste rock wool based heavy metal adsorbent with a porous structure.

[0034] Example 2:

[0035] 1. Placing the waste rock wool in a muffle furnace for high temperature treatment, wherein the temperature of the muffle furnace is set to 425°C, the initial temperature is 25°C, the temperature rising speed is 16°C / min, and the high temperature treatment time is 25 min, to remove the colloidal substance on the surface of the rock wool;

[0036] 2. Mixing and stirring the high temperature treated rock wool with a polyethyleneimine solution and a polyethylene glycol solution for a period of time, wherein the mass ratio between the rock wool and the polyethyleneimine is 1:7.2, the solid-liquid mass volume ratio of the polyethyleneimine and the aqueous solution is 1.2 g:10 mL, and the mass ratio between the polyethylene glycol and the polyethyleneimine is 1:3.6;

[0037] 3. Treating the rock wool dispersion solution by freeze-drying, wherein the freeze-drying temperature is -55°C and the freeze-drying time is 32 h, to obtain the polyethyleneimine modified rock wool;

[0038] 4. Immersing the polyethyleneimine modified rock wool in an aqueous solution containing ammonium persulfate initiator, acrylic monomer and acrylic glycidyl acrylate monomer for a period of time, wherein the acrylic monomer and the acrylic glycidyl acrylate monomer include acrylic acid, methacrylic acid, acrylic glycidyl acrylate, methacrylic glycidyl acrylate and combinations thereof, the mass ratio among the ammonium persulfate, the acrylic monomer and the acrylic glycidyl acrylate monomer is 0.1:5:5, and the concentration of the ammonium persulfate in the water is 0.05 mol / L; then taking out the rock wool; and then heating the rock wool to initiate a polymerization reaction, wherein the polymerization temperature is 80°C and the polymerization time is 3 h;

[0039] 5. Washing the rock wool material with deionized water to remove the polyethylene glycol, and drying to obtain the polyethyleneimine-polyacrylic acid modified waste rock wool based heavy metal adsorbent with a porous structure.

[0040] Example 3:

[0041] 1. The waste rock wool is placed in a muffle furnace for high temperature treatment, the muffle furnace temperature is set to 425℃, the initial temperature is 25℃, the heating rate is 16℃ / min, and the high temperature treatment time is 25min to remove the colloidal on the surface of the rock wool; after the rock wool is cooled, the rock wool is soaked in a 2.5mol / L hydrochloric acid solution, and the acid treatment time is 12min to expose the hydroxyl groups of the rock wool, obtaining acidified rock wool;

[0042] 2. After the acidified rock wool is washed, filtered, and dried, it is mixed with a polyethyleneimine and a polyethylene glycol solution and stirred for a period of time, wherein the mass ratio between the acidified rock wool and the polyethyleneimine is 1:7.2, the solid-liquid mass-volume ratio of the polyethyleneimine and the aqueous solution is 1.2g:10mL, and the mass ratio between the polyethylene glycol and the polyethyleneimine is 1:3.6;

[0043] 3. The polyethyleneimine modified rock wool is obtained by filtration, and is immersed in an aqueous solution containing an ammonium persulfate initiator, an acrylic monomer, and an epoxy propyl acrylate monomer for a period of time, and then taken out, wherein the acrylic monomer and the epoxy propyl acrylate monomer include acrylic acid, methacrylic acid, epoxy propyl acrylate, epoxy propyl methacrylate, and combinations thereof, the mass ratio among the ammonium persulfate, the acrylic monomer, and the epoxy propyl acrylate monomer is 0.1:5:5, and the concentration of the ammonium persulfate in water is 0.05mol / L; then the rock wool is heated to initiate the polymerization reaction, and the polymerization temperature is 80℃ and the polymerization time is 3h;

[0044] 5. The rock wool material is washed with deionized water to remove the polyethylene glycol, and after drying, a polyethyleneimine-polyacrylic acid modified waste rock wool based heavy metal adsorbent is obtained.

[0045] Example 4:

[0046] 1. The waste rock wool is placed in a muffle furnace for high temperature treatment, the muffle furnace temperature is set to 425℃, the initial temperature is 25℃, the heating rate is 16℃ / min, and the high temperature treatment time is 25min to remove the colloidal on the surface of the rock wool; after the rock wool is cooled, the rock wool is soaked in a 2.5mol / L hydrochloric acid solution, and the acid treatment time is 12min to expose the hydroxyl groups of the rock wool, obtaining acidified rock wool;

[0047] 2. After the acidified rock wool is washed, filtered, and dried, it is mixed with a polyethyleneimine and a polyethylene glycol solution and stirred for a period of time, wherein the mass ratio between the acidified rock wool and the polyethyleneimine is 1:7.2, the solid-liquid mass-volume ratio of the polyethyleneimine and the aqueous solution is 1.2g:10mL, and the mass ratio between the polyethylene glycol and the polyethyleneimine is 1:3.6;

[0048] 3. The polyethyleneimine modified rock wool is obtained by treating the rock wool dispersion with a freeze-drying method, the freeze-drying temperature is -55 DEG C, and the freeze-drying time is 32 h.

[0049] Example 5: Comparative experiment of adsorption of heavy metal ions

[0050] 10 mg of each of the waste rock wool based heavy metal adsorbents obtained in Examples 1-4 is taken, and the adsorbents are respectively put into 100 mL of simulated wastewater with a concentration of 50 mg / L of Cd 6+ , Cu 2+ , Pb 2+ (pH is 6), under the conditions of a temperature of 25 DEG C and a rotating speed of 150 rpm, oscillation reaction is carried out for 24 hours, then 0.45 mu m filter membrane is used for filtration, and the remaining concentrations of Cd 6+ , Cu 2+ , Pb 2+ in the solution are respectively determined by using an ultraviolet spectrophotometer, and the adsorption efficiency results are shown in the following table.

[0051]

[0052] It can be seen from the above table that the best adsorption effect is obtained in Example 1. This is because acidification treatment is beneficial to the exposure of the hydroxyl group on the surface of the rock wool, so as to increase the grafting amount of polyethyleneimine on the surface of the rock wool; the freeze-drying treatment gives the material a porous structure, and the porous structure can effectively increase the specific surface area of the material, so as to improve the adsorption performance of the material; the modified rock wool is immersed in an aqueous solution containing ammonium persulfate initiator, acrylic monomer and acrylic acid glycidyl ester monomer, and then polymerization is initiated by heating, so that polyacrylic acid is generated on the surface of the rock wool, and the adsorption effect of the material is further improved, so that the heavy metal adsorbent prepared in the application has good adsorption performance.

[0053] Example 6: Adsorption experiment of different mass ratios between acidified rock wool and polyethyleneimine

[0054] The mass ratio between acidified rock wool and polyethyleneimine is changed to prepare a heavy metal adsorbent, and the remaining conditions are the same as in Example 1. 10 mg of the obtained adsorbent is respectively put into 100 mL of simulated wastewater with a concentration of 50 mg / L of Cd 6+ , Cu 2+ , Pb 2+ (pH is 6), under the conditions of a temperature of 25 DEG C and a rotating speed of 150 rpm, oscillation reaction is carried out for 24 hours, then 0.45 mu m filter membrane is used for filtration, and the remaining concentrations of Cd 6+ , Cu 2+ , Pb 2+ in the solution are respectively determined by using an ultraviolet spectrophotometer, and the adsorption efficiency results are shown in the following table.

[0055]

[0056] As shown in the table above, the best adsorption effect was achieved when the mass ratio of acidified rock wool to polyethyleneimine was 1:7.2. With the gradual increase of the mass ratio of acidified rock wool to polyethyleneimine, the content of grafted and cross-linked polyethyleneimine on the rock wool surface increased, and the content of amine groups also increased. However, when the mass ratio of acidified rock wool to polyethyleneimine further increased, the content of grafted and cross-linked polyethyleneimine on the rock wool surface reached saturation, so the adsorption efficiency did not change significantly. Conversely, when the mass ratio of acidified rock wool to polyethyleneimine was small, the limited content of grafted and cross-linked polyethyleneimine on the rock wool surface led to a lower adsorption efficiency. Therefore, a mass ratio of 1:7.2 between acidified rock wool and polyethyleneimine was considered a more suitable ratio.

[0057] Example 7: Adsorption experiments under different pH conditions

[0058] Prepare 100 mL of Cd solution with a concentration of 100 mg / L. 6+ Cu 2+ Pb 2+ Simulated wastewater was prepared by adding 10 mg of the waste rock wool-based heavy metal adsorbent prepared according to the method in Example 1 to each group of simulated wastewater. After shaking for 24 hours at pH values ​​of 2, 3, 4, 5, 6, and 7, a temperature of 25°C, and a rotation speed of 150 rpm, the solution was filtered through a 0.45 μm filter membrane, and the Cd concentration in the solution was determined using a UV spectrophotometer. 6+ Cu 2+ Pb 2+ The remaining concentration was determined to assess its adsorption capacity.

[0059] The above experimental test results are as follows Figure 1 As shown, Figure 1 The above-described waste rock wool-based heavy metal adsorbent prepared in Example 1 is shown to exhibit its effect on Cd under different pH conditions. 6+ Cu 2+ Pb 2+ Results of removal rate and adsorption capacity tests. The optimal pH value is 6; at pH = 6, the adsorption of Pb... 2+ The maximum adsorption capacity was 986.23 mg / g for Cu. 2+ The maximum adsorption capacity was 963.87 mg / g for Cd. 6+ The maximum adsorption capacity was 959.39 mg / g, and the adsorption capacities were all close to 1000 mg / g. Even under strongly acidic conditions (pH=2), the adsorption capacity for Cd was [not specified]. 6+ Cu 2+ Pb 2+The adsorption capacity can reach approximately 350 mg / g, and the adsorbent maintains its complete physical state even under strongly acidic conditions. It can be seen that the waste rock wool-based heavy metal adsorbent prepared in Example 1 exhibits good adsorption capacity for Cd at pH = 6. 6+ Cu 2+ Pb 2+ All of them have good removal capabilities and high chemical stability.

[0060] Example 8: Adsorption experiments under different time conditions

[0061] Prepare Pb solutions with pH=6 and concentrations of 50, 75, and 100 mg / L per 100 mL. 2+ The simulated wastewater was treated with 10 mg of the waste rock wool-based heavy metal adsorbent prepared by the method in Example 1. Other conditions were the same as in Example 2.

[0062] The above experimental test results are as follows Figure 2 As shown, Figure 2 The waste rock wool-based heavy metal adsorbent prepared in Example 1 above is shown to adsorb Pb at pH=6 under different time conditions. 2+ The adsorption capacity is shown in the figure. The adsorption capacity almost reaches its peak within 400 minutes, and then tends to reach equilibrium, exhibiting excellent adsorption performance.

[0063] Example 9: Adsorption experiments under different initial concentration conditions

[0064] Prepare Pb solutions with pH=6 and concentrations of 20, 50, 100, 150, and 200 mg / L per 100 mL. 2+ The simulated wastewater was treated with 10 mg of the waste rock wool-based heavy metal adsorbent prepared by the method in Example 1. Other conditions were the same as in Example 2.

[0065] The above experimental test results are as follows Figure 3 As shown, Figure 3 The waste rock wool-based heavy metal adsorbent prepared in Example 1 above is shown to exhibit its effect on Pb at different initial concentrations at pH=6. 2+ The removal rate and adsorption capacity of Pb. As shown in the figure, with the increase of Pb... 2+ With increasing initial concentration, the adsorbent's effect on Pb 2+ The removal rate decreased slightly, but remained above 95%, and the total adsorption capacity increased significantly with increasing initial concentration, particularly in Pb. 2+ At an initial concentration of 200 mg / L, the adsorption capacity can even reach 1808.34 mg / g. This indicates that the adsorbent provided by this invention has a large adsorption potential.

[0066] The application utilizes waste rock wool to prepare a metal ion adsorbent, and uses waste rock wool generated in industrial production and daily life as raw material, so that the cost is low, the chemical stability is high, the prepared adsorbent has excellent adsorption performance on various heavy metal ions, and the adsorbent is in block shape and is easy to recycle, effectively solves the problem that waste rock wool is difficult to handle, and plays an important role in water environment protection.

[0067] The above only describes the preferred embodiments of the present application and is not used to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a metal ion adsorbent using waste rock wool, characterized by The method comprises the following steps: Step 1: placing waste rock wool in a muffle furnace for high-temperature heating for a period of time, and then soaking the cooled waste rock wool in a hydrochloric acid solution to obtain acidified rock wool; Step 2: washing, filtering and drying the acidified rock wool, mixing the dried acidified rock wool with a polyethyleneimine solution and a polyethylene glycol solution, and stirring for a period of time to obtain a rock wool dispersion; Step 3: freeze-drying the rock wool dispersion to obtain modified rock wool; Step 4: immersing the modified rock wool in an aqueous solution containing an ammonium persulfate initiator, an acrylic monomer and an epoxypropyl acrylate monomer for a period of time, then taking out the rock wool, and heating the rock wool to initiate a polymerization reaction; Step 5: washing the rock wool material with deionized water to remove the polyethylene glycol, and drying to obtain a porous polyethyleneimine-polyacrylic modified waste rock wool-based heavy metal adsorbent.

2. The method of claim 1, wherein in step 1, the temperature of the high-temperature heating of the muffle furnace is set to 425°C, and the treatment time is 25 min.

3. The method of claim 1, wherein in step 1, the concentration of the hydrochloric acid solution is 2.5 mol / L, and the acid treatment time is 12 min.

4. The method of claim 1, wherein in step 2, the mass ratio of the acidified rock wool to the polyethyleneimine is 1:3.6-9, and the mass ratio of the polyethylene glycol to the polyethyleneimine is 1:3.

6.

5. The method of claim 4, wherein in step 2, the mass ratio of the acidified rock wool to the polyethyleneimine is 1:7.

2.

6. The method of claim 1, wherein in step 4, the acrylic monomer is selected from acrylic acid and methacrylic acid, and the epoxypropyl acrylate monomer is selected from epoxypropyl acrylate and methacrylic acid epoxypropyl ester.

7. The method of claim 6, wherein the mass ratio of the ammonium persulfate, the acrylic monomer and the epoxypropyl acrylate monomer is 0.1:5:

5.

8. The method of claim 1, wherein in step 4, the polymerization reaction temperature is 80°C, and the polymerization time is 3 h.

9. Use of the metal ion adsorbent prepared by any one of the methods of claims 1-8 in the adsorption treatment of heavy metal wastewater.

10. The use of claim 9, wherein in the adsorption treatment of heavy metal wastewater, the system pH is 4-7. ​ ​ ​ ​ ​ ​ ​ ​

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