CN101948554A - Weak acid cation exchange microballoon resin of magnetic acrylic acid series and synthesis method thereof - Google Patents

Abstract

，其中n为1，2，3......；其弱酸体积交换容量为：1.0～5.0mol/L，平均粒径为20～500μm。其比饱和磁化强度为5.1～33.4emu/g，弱酸交换容量为1.0～5.0mol/L。本发明公开的微球树脂可用于多种水体的处理中，去除氨氮以及钙、镁、铜、镍、镉等多种金属离子。The invention discloses a magnetic acrylic weak acid cation exchange microsphere resin and a synthesis method thereof, belonging to the field of magnetic resins. By uniformly mixing magnetic particles with a size of 0.01-10 μm with the oil phase, carrying out suspension polymerization at a certain temperature and condition, and finally forming a magnetic weak acid cation exchange resin after hydrolysis. This microsphere resin is composed of a weak acid cation exchange microsphere resin framework and magnetic particles wrapped in it. The weight ratio of the resin framework to the magnetic particles is 1:0.05-1. The basic structural formula of the resin framework is as follows:

, where n is 1, 2, 3...; its weak acid volume exchange capacity is: 1.0-5.0 mol/L, and the average particle size is 20-500 μm. Its specific saturation magnetization is 5.1-33.4emu/g, and its weak acid exchange capacity is 1.0-5.0mol/L. The microsphere resin disclosed by the invention can be used in the treatment of various water bodies to remove various metal ions such as ammonia nitrogen and calcium, magnesium, copper, nickel, cadmium and the like.

Description

Magnetic acrylic weak acid cation exchange microsphere resin and its synthesis method

technical field

The invention discloses an acrylic weak acid cation exchange microsphere resin and a synthesis method thereof, more specifically an acrylic weak acid cation exchange microsphere resin containing magnetic particles and a synthesis method thereof.

Background technique

The particle size of the traditional weak acid cation exchange resin is 0.3mm ~ 1.2mm, and the fixed bed process is generally used in the application. If the powder microsphere resin with smaller particle size is synthesized, its desorption and adsorption performance can be further improved in application due to the increase of its external specific surface area. However, in the operation of the fixed bed process, the resin with too small particle size will increase the water resistance and reduce the amount of treated water. The magnetic particles are implanted into the resin with small particle size to make it magnetic, so as to solve the separation problem of the resin, and the traditional fixed bed process can be replaced by the fully mixed contact pool process, which not only improves the desorption and adsorption performance of the resin, but also The difficult problem of dealing with a small amount of water is avoided. At the same time, the contact tank process is easy to operate, low in operating costs, and can be quickly adjusted according to the resin treatment object and the standard after treatment, and has strong applicability to different water bodies.

However, the synthesis of magnetic weak acid cation exchange resins is still technically imperfect. The main difficulty lies in how to stably disperse the magnetic particles in the resin skeleton so that the resin maintains a certain degree of magnetism for a long time. The preparation of magnetic resin usually requires introducing magnetic particles into the oil phase and then carrying out polymerization reaction. The synthesis process of a magnetic ion exchange resin disclosed in US Pat. No. 2642514 and CN 101440166 all makes the magnetic particles uniform in the monomer Dispersion, but the particle size of this resin is not uniform, and the synthesis process is difficult to control. The methods disclosed in US Patent No.5900146 and CN 1699447 all use stabilizers containing amine groups to realize the dispersion of _Fe3O4 particles in the oil phase, and the defect is that the stabilizers react with the active groups in _the monomers , leading to low switching capacity. U.S. University of Florida Jennifer N.Apell et al. mentioned in the article published in the magazine "Water Research" in 2010 that the magnetic weak acid cation exchange resin (MIEX-Na resin) synthesized by Australia Orica company has a volume exchange capacity of 0.52 mmol/mL. Compared with conventional acrylic weak acid cation exchange resins, the exchange capacity is too low.

Contents of the invention

1. The technical problem to be solved by the invention

The purpose of the present invention is to realize the stable and uniform distribution of magnetic particles in the polymer by using low-cost raw materials and simple operation methods, and to synthesize a magnetic acrylic weak acid cation exchange material with high magnetic properties and high exchange capacity. microsphere resin.

2. Technical solution

Principle of the present invention: Utilize acrylic monomer, mix with cross-linking agent and porogen to form oil phase, mix oil phase with magnetic particles uniformly, carry out suspension polymerization; after polymerized magnetic polymer particles are hydrolyzed, form Magnetic acrylic weak acid cation exchange microsphere resin.

Technical scheme of the present invention:

Magnetic acrylic weak acid cation exchange microsphere resin is composed of weak acid cation exchange microsphere resin framework and magnetic particles wrapped in it. The weight ratio of resin framework to magnetic particles is 1:0.05~1. The basic structural formula of resin framework is as follows:

其中n为1，2，3......；其弱酸体积交换容量为：1.0～5.0mol/L，平均粒径为20～500μm。

Wherein, n is 1, 2, 3...; the weak acid volume exchange capacity is 1.0-5.0 mol/L, and the average particle size is 20-500 μm.

The weight ratio of the above-mentioned resin skeleton to the magnetic particles is preferably 1:0.1 to 1:0.4;

The particle size of the novel magnetic acrylic weak acid cation exchange microsphere resin is preferably 100-200 μm;

The magnetic particles refer to Fe ₃ O ₄ , γ-Fe ₂ O ₃ , stainless steel powder, iron-nickel alloy particles, the size of which is 0.01-10 μm, preferably 0.1-3 μm;

The novel magnetic acrylic weak acid cation exchange microsphere resin has a specific saturation magnetization of 5-35 emu/g;

The novel magnetic acrylic weak acid cation exchange microsphere resin has a weak acid volume exchange capacity of 1.0-5.0 mmol/mL;

The present invention provides the synthetic method of above-mentioned magnetic acrylic series weak acid cation exchange microsphere resin, and its steps are as follows:

(a) adding 0.2% to 3% of the dispersant and 8 to 23% of the water phase by mass in the water phase;

(b) The oil phase is composed of a reactant and a porogen, and the weight ratio of the reactant to the porogen is 1: 0.1 to 1: 1.5, wherein the reactant includes a monomer and a cross-linking agent, and the ratio of the monomer and the cross-linking agent is The weight ratio is 1:0.02～1:0.2;

(c) adding 0.4% to 3% benzoyl peroxide or azobisisobutyronitrile in the oil phase, stirring to fully dissolve the initiator;

(d) adding magnetic particle dispersants accounting for 0.5% to 5% by weight of the oil phase into the oil phase, and adding magnetic particles with a particle diameter of 0.01 to 10 μm into the oil phase, the weight ratio of the magnetic particles to the reactants is 1:20～1:1;

(e) Add the oil phase containing the initiator and magnetic particles into the stirred water phase. During the addition, the stirring speed is 100-500rpm, the temperature is controlled at 50-80°C, and the reaction temperature is 85-95°C after 2-8 hours of reaction. Keep it warm for 1-15 hours, cool down and treat to get black or reddish-brown microsphere resin, extract or wash and then dry;

(f) mixing the microsphere resin obtained in step (d) with ethanol and sodium hydroxide aqueous solution. The mass ratio of microsphere resin to ethanol is 1:1-1:5; the ratio of microsphere resin to sodium hydroxide aqueous solution is 1:2-1:5; the concentration of sodium hydroxide aqueous solution is 10-30%;

(g) Stir and heat the system in step (e) to 60-100°C, keep it warm for 4-16 hours and discharge;

(h) After discharging, wash to neutral with deionized water. It can be converted into hydrogen-type magnetic weak acid cation exchange microsphere resin with hydrochloric acid solution, and can also be converted into sodium type magnetic weak acid cation exchange microsphere resin with sodium hydroxide solution.

The dispersing agent used in step (a) is selected from gelatin, polyvinyl alcohol, activated calcium phosphate, guar gum, hydroxyethyl cellulose, methyl cellulose, sodium dodecylbenzene sulfonate, lignin sulfonic acid One or more mixtures of sodium;

The monomer used in the step (b) is selected from one or more mixtures of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate;

The crosslinking agent in step (b) is selected from ethylene glycol dimethacrylate, ethylene glycol diethyl diallyl ester, trimethacrylic acid (trimethylolpropyl) ester, triallyl One or more mixtures of cyanurate and divinylbenzene;

The main component of the porogen used in the step (b) is toluene, xylene, ethyl acetate, 200 ^# solvent naphtha, Virahol, n-butanol, cyclohexanol, liquid wax, n-heptane, n-octane One or more mixtures of , isooctane and n-decane;

The magnetic particle dispersant mentioned in step (d) refers to one or more of various silane coupling agents, titanate coupling agents, hyperdispersants, and surfactants;

The magnetic particles mentioned in steps (d) and (e) refer to Fe ₃ O ₄ , γ-Fe ₂ O ₃ , stainless steel powder, iron-nickel alloy particles, the size of which is 0.01-10 μm.

3. Beneficial effect

The invention provides magnetic acrylic weak acid cation exchange microsphere resin and its synthesis method. The magnetic acrylic weak acid cation exchange microsphere resin synthesized by the present invention has an exchange capacity higher than that of current literature reports and any magnetic Weak acid cation exchange microsphere resin. Its high weak acid exchange capacity, its excellent adsorption and desorption kinetic properties and easier separation characteristics due to its small particle size can replace traditional weak acid cation exchange resins, especially suitable for water hardness, ammonia nitrogen and various heavy metals, etc. Removal of cationic contaminants.

Detailed ways

Example 1

Add 500 g of 3% gelatin by weight and 23% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 100-150 rpm. The mixed solution of 100g methyl acrylate, 2g trimethacrylic acid (trimethylolpropyl) ester, 1.0g azobisisobutyronitrile, 100g toluene, 53g ethyl acetate and 102g particle size of about 0.1μm four After the iron oxide magnetic particles are evenly mixed, add them to a three-necked flask and raise the temperature to 50°C, keep for 8 hours, then raise the temperature to 85°C, keep for 15 hours, and then discharge; wash with ethanol and dry, add 2 times the amount of resin Ethanol by weight and 20% sodium hydroxide aqueous solution that is 2 times the weight of the resin are kept at 60°C for 16 hours and then discharged; washed with deionized water to neutrality, washed with hydrochloric acid solution to obtain hydrogen-type magnetic weak acid cations Exchange microsphere resin.

The obtained weak acid cation exchange microsphere resin is composed of weak acid cation exchange microsphere resin skeleton and magnetic particles wrapped in it, the particle size is mainly distributed in 300-400μm, the volume exchange capacity of weak acid can reach 4.00mmol/ml, and the specific saturation The magnetic strength is 33.4emu/g, and the basic structural formula of the resin skeleton is as follows:

Example 2

Add 500 g of 1% polyvinyl alcohol and 8% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 100-150 rpm. A mixed solution of 100g methyl acrylate, 2g trimethacrylate (trimethylolpropyl) ester, 1.0g benzoyl peroxide, 100g toluene, 53g ethyl acetate and 102g γ- After the ferric oxide particles are uniformly mixed, they are added to a three-necked flask and heated to 50°C, kept for 8 hours, then heated to 85°C, kept for 15 hours, and then discharged; washed with ethanol and dried, added 2 times the amount of resin Ethanol by weight and 20% sodium hydroxide aqueous solution that is 2 times the weight of the resin are kept at 60°C for 16 hours and then discharged; washed with deionized water to neutrality, washed with hydrochloric acid solution to obtain hydrogen-type magnetic weak acid cations Exchange microsphere resin.

The obtained weak acid cation exchange microsphere resin, the particle size is mainly distributed in 20 ~ 60 μm, the volume exchange capacity of weak acid can reach 4.00mol/L, the specific saturation magnetic intensity is 33.4emu/g, and the remanence is 150Oe. Its basic structure is the same as that of the embodiment 1.

Example 3

Add 500 g of polyvinyl alcohol with a weight ratio of 0.2% and 5% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 150-200 rpm. 90g methyl acrylate, 10g methacrylic acid, 15g trimethacrylic acid (trimethylolpropyl) ester, 5g triallyl cyanurate, 0.36g benzoyl peroxide, 10g toluene, 2g 200 ^# The mixed solution of solvent oil and 6g ferroferric oxide magnetic particles with a particle size of about 0.1μm are uniformly mixed, then added to a three-necked flask and heated to 55°C, kept for 8 hours, heated to 85°C, kept for 10 hours, and then discharged . Wash the material with ethanol and dry it, add 3 times the ethanol of the resin weight and 4 times the 30% sodium hydroxide solution, keep it at 90°C for 10h, then discharge the material, wash it with deionized water until it is neutral, and wash it with sodium hydroxide After the solution is transformed, it is washed and the sodium-type magnetic weak acid cation exchange microsphere resin is obtained.

The obtained magnetic weak acid cation exchange microsphere resin mainly has a particle size of 200-300 μm, a weak acid volume exchange capacity of 3.67 mmol/ml, and a specific saturation magnetic strength of 9.2 emu/g. Its basic structural formula is the same as in Example 1.

Example 4

Add 500 g of 3% active calcium phosphate and 20% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 400-500 rpm. A mixed solution of 90g methyl acrylate, 10g butyl methacrylate, 5g trimethacrylic acid (trimethylolpropyl) ester, 5g divinylbenzene, 0.68g azobisisobutyronitrile, 22g 200 ^# solvent oil After being uniformly mixed with 8 g of ferroferric oxide magnetic particles with a particle size of about 0.1 μm, it was added to a three-necked flask and heated to 60° C., kept for 5 hours, then raised to 88° C. and kept for 12 hours. After washing and discharging the material with ethanol and drying it, add 3 times the ethanol of the resin weight and 10% sodium hydroxide solution 5 times the resin weight, react at 100°C for 4 hours, and then discharge the material, and wash it with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin has a particle size mainly distributed in the range of 80-140 μm, a weak acid volume exchange capacity of 3.49 mol/L, a specific saturation magnetic strength of 5.1 emu/g, and its basic structural formula is the same as in Example 1.

Example 5

Add 500 g of 1.5% gull gum by weight and 20% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 250-300 rpm. 80g ethyl acrylate, 20g acrylic acid, 5g trimethacrylate (trimethylolpropyl) ester, 10g ethylene glycol dimethacrylate, 3.45g benzoyl peroxide, 50g xylene, 65g isopropanol After uniformly mixing the mixed solution with 80g of γ-Fe ₂ O ₃ magnetic particles with a particle size of about 0.2μm, add it into a three-necked flask and raise the temperature to 65°C, keep it for 6 hours, raise the temperature to 90°C and keep it for 5 hours, then discharge . Wash and discharge the material with ethanol and dry it, add 1 times the weight of the resin in ethanol and 15% sodium hydroxide solution that is 4 times the weight of the resin, react at 70°C for 14 hours, and then discharge the material, wash with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin mainly has a particle size of 300-500 μm, a weak acid volume exchange capacity of 3.13 mol/L, and a specific saturation magnetic strength of 33.4 emu/g. Its basic structural formula is the same as in Example 1.

Example 6

Add 500 g of hydroxyethyl cellulose with a weight ratio of 0.5% and 15% sodium chloride aqueous solution into a 2L three-neck flask, and control the stirring speed at 300-400 rpm. 90g methyl methacrylate, 30g methyl acrylate, 30g ethyl acrylate, 5g ethylene glycol dimethacrylate, 2.5g triallyl cyanurate, 0.9g azobisisobutyronitrile, 30g n- The mixed solution of butanol, 30g liquid wax and 13g stainless steel powder magnetic particles with a particle size of about 0.6μm are uniformly mixed, then added to a three-necked flask and heated to 60°C, kept for 5 hours, then raised to 90°C, kept for 8 hours Discharge. After cleaning and discharging the material with ethanol and drying it, add 3 times the ethanol of the resin weight and 1.5 times the 30% sodium hydroxide solution of the resin weight, react at 95 ° C for 6 hours, and then discharge the material, and wash it with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin is composed of a weak acid cation exchange microsphere resin framework and magnetic particles wrapped in it, the particle size is mainly distributed in the range of 120-150 μm, and the weak acid volume exchange capacity reaches 1.8mol/L, which is relatively The saturation magnetic intensity is 15.1emu/g, the remanence is 30Oe, and the basic structural formula of the resin skeleton is as follows:

Example 7

Add 500 g of 0.1% by weight methylcellulose and 15% sodium chloride aqueous solution into a 2L three-necked flask, and control the stirring speed at 250-300 rpm. 140g methyl acrylate, 40g butyl methacrylate, 10g trimethacrylate (trimethylolpropyl) ester, 5g triallyl cyanurate, 1g azobisisobutyronitrile, 80g xylene, The mixed solution of 60g of n-heptane and 11g of iron-nickel alloy magnetic particles with a particle size of about 0.8μm are uniformly mixed, then added to a three-necked flask and heated to 70°C, kept for 4 hours, then heated to 92°C, kept for 3 hours and then released material. After washing and discharging the material with ethanol and drying it, add 1.5 times the ethanol of the resin weight and 3.5 times the 20% sodium hydroxide solution of the resin weight, react at 75°C for 10 hours, and then discharge the material, and wash it with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin, the particle size is mainly distributed in 180-250 μm, the volume exchange capacity of weak acid reaches 2.06mol/L, the specific saturation magnetic intensity is 7.5emu/g, and the remanence is 79Oe. Its basic structural formula is the same as that of the implementation example 1.

Example 8

Add 500 g of 0.8% gelatin by weight, 0.1% sodium dodecylbenzenesulfonate, and 15% sodium bicarbonate aqueous solution into a 2L three-necked flask, and control the stirring speed at 450-500 rpm. 140g methyl acrylate, 20g glycidyl methacrylate, 10g trimethacrylate (trimethylolpropyl) ester, 20g triallyl cyanurate, 2.0g benzoyl peroxide, 200g n- The mixed solution of octane, 25g of n-decane and 13g of ferroferric oxide magnetic particles with a particle size of about 0.1-5μm are uniformly mixed, then added to a three-necked flask and heated to 75°C, kept for 4 hours, and then heated to 92°C, Discharge after keeping 6 hours. After cleaning and discharging the material with ethanol and drying it, add 2 times the ethanol of the weight of the resin and 25% sodium hydroxide solution of 1 times the weight of the resin, react at 85°C for 8 hours and then discharge the material, wash with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin, the particle size is mainly distributed in 150-200 μm, the strong base exchange capacity reaches 2.89mol/L, the specific saturation magnetic intensity is 24emu/g, and the remanence is 200Oe. Its basic structural formula is the same as that of the embodiment 1.

Example 9

500 g of gelatin containing 2.4% by weight, 0.5% sodium lignosulfonate, and 15% sodium chloride aqueous solution were added into a 2L three-necked flask, and the stirring speed was controlled at 250-300 rpm. A mixed solution of 151g methyl acrylate, 29g divinylbenzene, 20g triallyl cyanurate, 2.55g benzoyl peroxide, 60g toluene, 5g isooctane and 40g iron nickel with a particle size of about 0.5μm After the alloy powder is uniformly mixed, it is added into a three-necked flask and heated to 60°C, kept for 5 hours, then raised to 95°C, kept for 1 hour, and discharged. After washing and discharging the material with ethanol and drying it, add 2 times the ethanol of the resin weight and 10% sodium hydroxide solution 5 times the resin weight, react at 80°C for 9 hours, and then discharge the material, and wash it with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin, the particle size is mainly distributed in 200～300 μm, the volume exchange capacity of weak acid reaches 4.94mol/L, the specific saturation magnetic intensity is 19.1emu/g, and the remanence is 90Oe. Its basic structural formula is the same as that of the embodiment 1.

Example 10

500 g of gelatin containing 2.4% by weight, 0.5% sodium lignosulfonate, and 15% sodium chloride aqueous solution were added into a 2L three-necked flask, and the stirring speed was controlled at 250-300 rpm. A mixed solution of 150g methyl acrylate, 50g acrylic acid, 20g divinylbenzene, 5g triallyl cyanurate, 2.55g benzoyl peroxide, 150g xylene, 50g isooctane and 40g particle size of about 0.5 After uniform mixing of μm iron-nickel alloy powder, it was added into a three-necked flask and the temperature was raised to 60°C, kept for 5 hours, then raised to 95°C, kept for 1 hour, and discharged. After washing and discharging the material with ethanol and drying it, add 2 times the ethanol of the resin weight and 10% sodium hydroxide solution 5 times the resin weight, react at 80°C for 9 hours and discharge the material, and wash it with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin mainly has a particle size of 150-200 μm, a weak acid volume exchange capacity of 3.28 mol/L, and a specific saturation magnetic strength of 19.1 emu/g. Its basic structural formula is the same as in Example 1.

Example 11

In embodiment 6, 10g trimethacrylate (trimethylolpropyl) ester, 5g triallyl cyanurate are replaced with 30g trimethacrylate (trimethylolpropyl) ester, all the other oil phase components With embodiment 6. Add the oil phase to a 2L three-neck flask, heat up to 60°C and stir for 10 minutes, then add 500g of active calcium phosphate and 2% sodium chloride aqueous solution containing 0.3% by weight, raise the temperature to 68°C, and keep the temperature for 4 hours. Keep at 95°C for 8 hours and then discharge. Wash and discharge the material with ethanol and dry it, add ethanol 5 times the weight of the resin and 20% sodium hydroxide solution 5 times the weight of the resin, react at 65°C for 11 hours and then discharge the material, wash with deionized water until neutral , transform with hydrochloric acid solution and wash to obtain hydrogen-type magnetic weak acid cation exchange microsphere resin.

The obtained magnetic weak acid cation exchange microsphere resin has a particle size mainly distributed in 180-250 μm, a weak acid volume exchange capacity of 2.23 mol/L, and a specific saturation magnetic strength of 10.31 emu/g. Its basic structural formula is the same as in Example 1.

Claims (10)

1. A magnetic acrylic acid series weak-acid cation-exchange microsphere resin is characterized in that it is made of weak-acid cation-exchange microsphere resin skeleton and magnetic particles wrapped therein, and the weight ratio of resin skeleton and magnetic particle is 1: 0.05～1 , the basic structural formula of the resin skeleton is as follows:

Wherein, n is 1, 2, 3...; the weak acid volume exchange capacity is 1.0-5.0 mol/L, and the average particle size is 20-500 μm. 2. The magnetic acrylic weak acid cation exchange microsphere resin according to claim 1, characterized in that its specific saturation magnetization is 5.1～33.4emu/g; 3. The magnetic acrylic weak acid cation exchange microsphere resin according to claim 2, characterized in that its remanence is 2～200Oe; 4. according to the synthetic method of magnetic acrylic acid series weak acid cation exchange microsphere resin described in any one in claim 1～3, its steps are as follows: (a) adding 0.2% to 3% of the dispersant and 8 to 23% of the water phase by mass in the water phase; (b) The oil phase is composed of a reactant and a porogen, and the weight ratio of the reactant to the porogen is 1: 0.1 to 1: 1.5, wherein the reactant includes a monomer and a cross-linking agent, and the ratio of the monomer and the cross-linking agent is The weight ratio is 1:0.02～1:0.2; (c) adding 0.4% to 3% benzoyl peroxide or azobisisobutyronitrile in the oil phase, stirring to fully dissolve the initiator; (d) adding magnetic particle dispersants accounting for 0.5% to 5% by weight of the oil phase into the oil phase, and adding magnetic particles with a particle diameter of 0.01 to 10 μm into the oil phase, the weight ratio of the magnetic particles to the reactants is 1:20～1:1. (e) Add the oil phase containing the initiator and magnetic particles into the stirred water phase. During the addition, the stirring speed is 100-500rpm, the temperature is controlled at 50-80°C, and the reaction temperature is 85-95°C after 2-8 hours of reaction. Keep it warm for 1-15 hours, cool down and treat to get black or reddish-brown microsphere resin, extract or wash and then dry; (f) mixing the microsphere resin obtained in step (d) with ethanol and sodium hydroxide aqueous solution. The mass ratio of microsphere resin to ethanol is 1:1-1:5; the ratio of microsphere resin to sodium hydroxide aqueous solution is 1:2-1:5; the concentration of sodium hydroxide aqueous solution is 10-30%; (g) Stir and heat the system in step (e) to 60-100°C, keep it warm for 4-16 hours and discharge; (h) After discharging, wash to neutral with deionized water. It can be converted into hydrogen-type magnetic weak acid cation exchange microsphere resin with hydrochloric acid solution, and can also be converted into sodium type magnetic weak acid cation exchange microsphere resin with sodium hydroxide solution. 5. according to the synthetic method described in claim 4, it is characterized in that the dispersant used in the step (a) selects gelatin, polyvinyl alcohol, activated calcium phosphate, gull gum, hydroxyethyl cellulose, methyl cellulose for use one or a mixture of sodium dodecylbenzenesulfonate, sodium lignosulfonate; 6. according to the synthetic method described in claim 4 or 5, it is characterized in that the monomer adopted in the step (b) is selected from acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methyl One or more mixtures of methyl acrylate and butyl methacrylate; 7. according to the synthetic method described in claim or 5, it is characterized in that the linking agent in the synthetic step (b) is selected from ethylene glycol dimethacrylate, ethylene glycol diethyl diallyl ester, One or more mixtures of (trimethylolpropyl) trimethacrylate, triallyl cyanurate, and divinylbenzene; 8. according to the synthetic method described in claim or 5, it is characterized in that the main component of the porogen used in the synthetic step (b) is toluene, xylene, ethyl acetate, 200 ^# solvent naphtha, Virahol, One or more mixtures of n-butanol, cyclohexanol, liquid wax, n-heptane, n-octane, isooctane and n-decane; 9. according to the synthetic method described in claim or 5, it is characterized in that the magnetic particle dispersant mentioned in its synthetic step (d) refers to silane coupling agent, titanate coupling agent, hyperdispersant, One or more of surfactants. 10. The synthesis method according to claim or 5, characterized in that the magnetic particles mentioned in the synthesis steps (d) and (e) are Fe ₃ O ₄ , γ-Fe ₂ O ₃ , stainless steel powder or The iron-nickel alloy particles have a size of 0.01-10 μm.