A porous ion exchange resin, its preparation method and use

Abstract

The application discloses a synthesis method of a porous ion exchange resin, and comprises the following steps: (1) a material system containing monomers, a crosslinking agent, an initiator and a porogen is subjected to a polymerization reaction; (2) the product after the polymerization in step (1) is filtered to obtain resin microspheres; (3) the resin microspheres obtained in step (2) are subjected to removal of the porogen and sulfonation to obtain the final porous ion exchange resin; wherein the porogen in step (1) at least comprises an inorganic porogen, and preferably comprises the inorganic porogen and an organic porogen; the content of the inorganic porogen is 5wt%-50wt% based on the total mass of the monomers, the crosslinking agent, the initiator and the porogen; and the content of the organic porogen is 0wt%-35wt%. The method can realize efficient and controllable preparation of the porous ion exchange resin.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material preparation, and particularly relates to a porous ion exchange resin and a preparation method and application thereof. BACKGROUND

[0002] Ion exchange resin is a commonly used water treatment material in industry, and can be used for removal of various pollutants in wastewater. Among them, ion exchange resin prepared by taking styrene-divinylbenzene crosslinked copolymer as a skeleton is one of the most commonly used ion exchange resins. According to the different structures and morphologies, the resin can be divided into gel type ion exchange resin and macroporous ion exchange resin. Compared with the gel type ion exchange resin, the macroporous ion exchange resin has the advantages of fast exchange speed, large mechanical strength and good regeneration performance, and has a broader application prospect.

[0003] The main means for preparing the macroporous ion exchange resin at present is to add an organic solvent which does not participate in the polymerization reaction in the oil phase, and then remove the organic solvent in the resin ball after polymerization, so as to leave the pore structure.

[0004] CN103122044A respectively takes styrene, divinylbenzene, benzoyl peroxide and toluene solution containing linear polystyrene as monomer, crosslinking agent, initiator and porogen to prepare macroporous ion exchange resin white ball, and makes -SO3H connected with the benzene ring in the copolymer skeleton through -CH2- in the sulfonation process, so as to solve the problem that the effect as a deiodine agent is poor, and the amount of the organic porogen is 2 to 3 times of the amount of the monomer in the preparation process. Su YQ et al. (Preparation and properties of macroporous anion exchange resin [J]. Journal of Beijing University of Aeronautics and Astronautics, 2003, 29(6): 4.) prepared a macroporous anion exchange resin based on styrene-divinylbenzene, and added rubber solvent oil as a porogen in an amount of 70% of the weight of the monomer in the preparation process. The prepared resin has good adsorption capacity and selectivity for gold in cyanide ore pulp.

[0005] However, the above methods for synthesizing macroporous resin all have certain limitations. First, compared with the gel type resin, a large amount of organic porogen needs to be added for synthesizing the macroporous ion exchange resin, which not only increases the cost, but also may cause environmental risk; in addition, it is difficult to control the pore structure and size of the resin synthesized by using the organic porogen, and it is difficult to obtain a suitable macroporous ion exchange resin according to the demand. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a porous ion exchange resin and a preparation method and application thereof. The method can realize efficient and controllable preparation of the porous ion exchange resin.

[0007] A first aspect of the present application is to provide a synthesis method of a porous ion exchange resin, which comprises the following steps:

[0008] (1) the material system containing monomer, crosslinking agent, initiator and porogen is subjected to polymerization reaction;

[0009] (2) the product after polymerization in step (1) is filtered to obtain resin microspheres;

[0010] (3) the resin microspheres obtained in step (2) are subjected to removal of porogen and sulfonation to obtain the final porous ion exchange resin;

[0011] In step (1), the porogen at least comprises inorganic porogen, preferably contains inorganic porogen and organic porogen, and the content of the inorganic porogen is 5wt%-50wt% based on the total mass of monomer, crosslinking agent and initiator, preferably 10wt%-40wt%; the content of the organic porogen is 0wt%-35wt%, preferably 5-10wt%.

[0012] In the method, the inorganic porogen is one or a mixture of several of calcium carbonate, magnesium hydroxide, aluminum oxide, aluminum hydroxide, zinc oxide, basic zinc carbonate and molecular sieve raw powder, and is preferably at least one of calcium carbonate, zinc oxide and molecular sieve raw powder. The molecular sieve raw powder comprises 4A molecular sieve and 13X molecular sieve raw powder.

[0013] In the method, the particle size of the inorganic porogen can be selected as required, and is generally 30-5000nm, preferably 50-1000nm.

[0014] In the method, the inorganic porogen is an oil-wet inorganic porogen after modification, and the oil-wet modification process is to contact the inorganic porogen with an oil-wet reagent to introduce oil-wet groups or oil-wet substances onto the surface of the inorganic porogen. The oil-wet reagent comprises but is not limited to one or any combination of silicone oil, hydrogen-containing silicone oil, stearic acid and sodium stearate.

[0015] In the method, a non-limiting oil-wet modification process of the inorganic porogen is as follows: the oil-wet reagent is dissolved in a solvent and fully mixed with the inorganic porogen, the powder obtained after mixing is heated, and the modified oil-wet inorganic porogen is obtained after reaction. The reaction temperature is 80-150℃, preferably 120℃; the reaction time is 5-60min, preferably 30min, and the mass ratio of the porogen to the oil-wet reagent in the material after fully mixing with the inorganic porogen is 100:5-100:10, preferably 100:7.5. The solvent is one or several of dichloromethane and dichloroethane.

[0016] In the method, step (1) first mixes the monomer, crosslinking agent and porogen to form an oil phase, and then adds the initiator; then the dispersant is dissolved in water to form an aqueous phase; finally, the oil phase and the aqueous phase are mixed for polymerization reaction.

[0017] In the method, the monomer is styrene, the addition amount is 40wt%-70wt%, preferably 50wt%-65wt%; the crosslinking agent is divinyl benzene, ethylene glycol dimethyl acrylate or a mixture thereof, the addition amount is 5%-30wt%, preferably 10wt%-16wt%; the initiator is benzoyl peroxide, azobisisobutyronitrile, the addition amount is 0.2wt%-1wt%, preferably 0.8wt%; the above addition amount is based on the total mass of the monomer, the crosslinking agent, the pore-forming agent and the initiator.

[0018] In the method, the organic pore-forming agent is one of cyclohexane, n-heptane, n-hexane, toluene, xylene or a mixture of any of them.

[0019] In the method, the dispersing agent is one of polyvinyl alcohol, gelatin, hydroxypropyl methyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose or a mixture of any of them, the addition amount is 0.01wt%-3wt%, the above mass is based on the mass of the aqueous phase.

[0020] In the method, the mass ratio of the oil phase and the aqueous phase is 1:2-1:5, preferably 1:3-1:4.

[0021] In the method, the polymerization reaction can be carried out under stirring and heating conditions, the stirring rate is 150-400 r / m, the reaction temperature is 60-95 ℃.

[0022] In the method, the removal of the pore-forming agent from the microspheres can be carried out before or simultaneously with the sulfonation; preferably, the resin microspheres obtained after polymerization are sulfonated using concentrated sulfuric acid, at the same time, the inorganic pore-forming agent in the resin is dissolved, obtaining a porous strong acid type cation exchange resin.

[0023] In the method, if the inorganic pore-forming agent used has low solubility in sulfuric acid (calcium carbonate), hydrochloric acid can be used to remove the inorganic pore-forming agent before sulfonation, and then the sulfonation reaction is carried out.

[0024] A porous ion exchange resin prepared by the above method, the exchange capacity of the porous ion exchange resin is 1.5-2.5meq / mL.

[0025] The porous ion exchange resin prepared by the above method can be used for removing heavy metal ions and hardness in water.

[0026] Compared with the prior art, the method for synthesizing a porous ion exchange resin has the following beneficial effects:

[0027] (1) The present application can select inorganic powder with corresponding particle size range as pore-forming agent according to the requirement of pore diameter, the prepared resin pore structure is controllable, the use of organic pore-forming agent is significantly reduced or avoided, the cost is reduced, and the potential environmental pollution risk is reduced;

[0028] (2) The inorganic pore-forming agent is modified in the present application, the modifier is dispersed in the dispersant, can be more uniformly mixed with the pore-forming agent, grafted to the surface of the pore-forming agent under heating conditions, so that the pore-forming agent has strong lipophilicity, can be better dispersed in the oil phase, prevent the powder from diffusing too much to the water phase in the reaction process, and improve the pore-forming efficiency;

[0029] (3) The present application uses inorganic pore-forming agent at the same time, adds a small amount of organic pore-forming agent, avoids extruding part of the inorganic powder in the process of changing from liquid to solid during polymerization of the organic phase, and improves the pore-forming effect. Embodiment

[0030] The following examples and comparative examples will further illustrate the preparation method of the porous ion exchange resin and its effects. The examples are implemented on the premise of the technical scheme of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0031] In the following examples, the experimental methods are the conventional methods in the art unless otherwise specified. The experimental materials used in the following examples can be purchased from a biochemical reagent store unless otherwise specified. In the context of the present application, the percentage is mass percentage unless otherwise specified.

[0032] In the present application, the pore-forming efficiency is investigated by the utilization rate of inorganic pore-forming agent, and the calculation method is as follows:

[0033] Utilization rate=(m1-m2) / m1x100%

[0034] Wherein, m1 is the addition amount of inorganic pore-forming agent, and m2 is the mass of residual pore-forming agent in the water phase after reaction.

[0035] In the present application, the static method is used to determine the exchange capacity of the ion exchange resin.

[0036] Example 1

[0037] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloroethane, mixed with 8 g calcium carbonate powder (30 nm), and reacted at 120°C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and hydrogen-containing silicone oil modified calcium carbonate powder and cyclohexane were added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide, hydrogen-containing silicone oil modified calcium carbonate powder, and cyclohexane in the oil phase were 65 wt%, 16 wt%, 0.8 wt%, 10.2 wt%, and 8 wt%, respectively; hydroxypropyl methylcellulose and gelatin were added to deionized water to form an aqueous phase, and the contents were 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and the mixture was heated at 80°C to polymerize, and then filtered to obtain resin white balls. The utilization rate of the modified calcium carbonate pore former was 95.81% by calculation; the white balls were soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.95 meq / ml.

[0038] Example 2

[0039] 0.5 g silicone oil was dissolved in 2.4 g dichloroethane, mixed with 10 g nano-zinc oxide powder (50 nm), and reacted at 80°C for 5 min to obtain modified nano-zinc oxide powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and silicone oil modified nano-zinc oxide powder and n-hexane were added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide, silicone oil modified nano-zinc oxide powder, and n-hexane in the oil phase were 50 wt%, 30 wt%, 0.8 wt%, 5 wt%, and 14.2 wt%, respectively; carboxymethyl cellulose was added to deionized water to form an aqueous phase, and the content was 0.5 wt%; 1 part of the oil phase was added to 3 parts of the aqueous phase under stirring at 300 r / m, and the mixture was heated at 95°C to polymerize, and then filtered to obtain resin white balls. The utilization rate of the modified nano-zinc oxide pore former was 91.23% by calculation; sulfonation was performed to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.87 meq / ml.

[0040] Example 3

[0041] Stearic acid 0.6 g was dissolved in 2.4 g dichloroethane, mixed with 6 g molecular sieve raw powder (particle size 1000 nm), and reacted at 150 °C for 60 min to obtain modified molecular sieve raw powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and the modified molecular sieve raw powder of stearic acid was added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide, and modified molecular sieve raw powder of stearic acid in the oil phase were 70 wt%, 5 wt%, 0.2 wt%, and 24.8 wt%, respectively; polyvinyl alcohol was added to deionized water to form an aqueous phase, and the content was 3 wt%; 1 part of the oil phase was added to 5 parts of the aqueous phase under stirring at 150 r / m, and after polymerization under heating at 80 °C, filtration was performed to obtain resin white balls, and the utilization rate of the modified molecular sieve pore-forming agent was calculated to be 89.12%; sulfonation was performed to obtain a porous ion exchange resin. Detection showed that the exchange capacity of the ion exchange resin was 1.79 meq / ml.

[0042] Example 4

[0043] Stearic acid sodium 2 g was dissolved in 8 g dichloroethane, mixed with 20 g calcium carbonate powder (5000 nm), and reacted at 120 °C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and the modified calcium carbonate stearate was added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide, and modified calcium carbonate stearate in the oil phase were 40 wt%, 9 wt%, 1 wt%, and 50 wt%, respectively; methyl cellulose was added to deionized water to form an aqueous phase, and the content was 0.5 wt%; 1 part of the oil phase was added to 3 parts of the aqueous phase under stirring at 300 r / m, and after polymerization under heating at 60 °C, filtration was performed to obtain resin white balls, and the utilization rate of the modified calcium carbonate pore-forming agent was calculated to be 87.17%; the white balls were soaked in 5% hydrochloric acid to remove the pore-forming agent, and then sulfonation was performed to obtain a porous ion exchange resin. Detection showed that the exchange capacity of the ion exchange resin was 1.57 meq / ml.

[0044] Example 5

[0045] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloroethane, mixed with 8 g calcium carbonate powder (particle size 50 nm), and reacted at 120 °C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and hydrogen-containing silicone oil modified calcium carbonate powder and n-heptane were added to form an oil phase, so that the content of styrene, divinylbenzene, benzoyl peroxide, hydrogen-containing silicone oil modified calcium carbonate powder, and n-heptane in the oil phase was 40 wt%, 10 wt%, 0.5 wt%, 14.5 wt%, and 35 wt%, respectively; hydroxyethyl cellulose and polyvinyl alcohol were added to deionized water to form an aqueous phase, and the content of hydroxyethyl cellulose and polyvinyl alcohol was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 3 parts of the aqueous phase under stirring at 300 r / m, and the polymerization was carried out under heating at 80 °C, followed by filtration to obtain resin white balls, and the utilization rate of the modified calcium carbonate pore former was calculated to be 96.97%; the white balls were soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was detected to be 1.85 meq / ml.

[0046] Example 6

[0047] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloroethane, mixed with 8 g calcium carbonate powder (particle size 50 nm), and reacted at 120 °C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and hydrogen-containing silicone oil modified calcium carbonate powder and n-heptane were added to form an oil phase, so that the content of styrene, divinylbenzene, benzoyl peroxide, hydrogen-containing silicone oil modified calcium carbonate powder, and n-heptane in the oil phase was 40 wt%, 10 wt%, 0.5 wt%, 14.5 wt%, and 35 wt%, respectively; hydroxyethyl cellulose and polyvinyl alcohol were added to deionized water to form an aqueous phase, and the content of hydroxyethyl cellulose and polyvinyl alcohol was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 3 parts of the aqueous phase under stirring at 300 r / m, and the polymerization was carried out under heating at 80 °C, followed by filtration to obtain resin white balls, and the utilization rate of the modified calcium carbonate pore former was calculated to be 96.97%; the white balls were soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was detected to be 1.85 meq / ml.

[0048] Example 7

[0049] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloroethane, mixed with 8 g calcium carbonate powder (particle size 50 nm), and reacted at 120°C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and hydrogen-containing silicone oil modified calcium carbonate powder and toluene were added to form an oil phase, so that the content of styrene, divinylbenzene, benzoyl peroxide, hydrogen-containing silicone oil modified calcium carbonate powder, and toluene in the oil phase was 65 wt%, 16 wt%, 0.8 wt%, 10 wt%, and 8.2 wt%, respectively; hydroxypropyl methylcellulose and gelatin were added to deionized water to form an aqueous phase, and the content of hydroxypropyl methylcellulose and gelatin was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and the polymerization was carried out under heating at 80°C, followed by filtration to obtain resin white balls, and the utilization rate of the modified calcium carbonate pore former was calculated to be 94.79%; the white balls were soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.88 meq / ml.

[0050] Example 8

[0051] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloroethane, mixed with 8 g calcium carbonate powder (particle size 50 nm), and reacted at 120°C for 30 min to obtain modified calcium carbonate powder; styrene, divinylbenzene, and benzoyl peroxide were mixed, and hydrogen-containing silicone oil modified calcium carbonate powder and toluene were added to form an oil phase, so that the content of styrene, divinylbenzene, benzoyl peroxide, hydrogen-containing silicone oil modified calcium carbonate powder, and toluene in the oil phase was 65 wt%, 16 wt%, 0.8 wt%, 10 wt%, and 8.2 wt%, respectively; hydroxypropyl methylcellulose and gelatin were added to deionized water to form an aqueous phase, and the content of hydroxypropyl methylcellulose and gelatin was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and the polymerization was carried out under heating at 80°C, followed by filtration to obtain resin white balls, and the utilization rate of the modified calcium carbonate pore former was calculated to be 94.79%; the white balls were soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.88 meq / ml.

[0052] Example 9

[0053] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloromethane, mixed with 8 g of aluminum oxide powder (1000 nm), and reacted at 120°C for 30 min to obtain modified aluminum oxide powder; styrene, divinylbenzene, and azobisisobutyronitrile were mixed, and hydrogen-containing silicone oil modified aluminum oxide powder and n-heptane were added to form an oil phase, so that the content of styrene, divinylbenzene, azobisisobutyronitrile, hydrogen-containing silicone oil modified aluminum oxide powder, and n-heptane in the oil phase was 65 wt%, 16 wt%, 1 wt%, 10 wt%, and 8 wt%, respectively; hydroxypropyl methyl cellulose and gelatin were added to deionized water to form an aqueous phase, and the content of hydroxypropyl methyl cellulose and gelatin was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and after polymerization under heating at 80°C, the resin white ball was obtained by filtration, and the utilization rate of the modified aluminum oxide pore former was calculated to be 95.87%; the white ball was soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.89 meq / ml.

[0054] Example 10

[0055] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloromethane, mixed with 8 g of aluminum oxide powder (1000 nm), and reacted at 120°C for 30 min to obtain modified aluminum oxide powder; styrene, divinylbenzene, and azobisisobutyronitrile were mixed, and hydrogen-containing silicone oil modified aluminum oxide powder and n-heptane were added to form an oil phase, so that the content of styrene, divinylbenzene, azobisisobutyronitrile, hydrogen-containing silicone oil modified aluminum oxide powder, and n-heptane in the oil phase was 65 wt%, 16 wt%, 1 wt%, 10 wt%, and 8 wt%, respectively; hydroxypropyl methyl cellulose and gelatin were added to deionized water to form an aqueous phase, and the content of hydroxypropyl methyl cellulose and gelatin was 0.05 wt% and 0.5 wt%, respectively; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and after polymerization under heating at 80°C, the resin white ball was obtained by filtration, and the utilization rate of the modified aluminum oxide pore former was calculated to be 95.87%; the white ball was soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.89 meq / ml.

[0056] Example 11

[0057] 0.6 g hydrogen-containing silicone oil was dissolved in 2.4 g dichloromethane, and mixed with 8 g of basic zinc carbonate powder (1000 nm) to obtain modified basic zinc carbonate powder after reaction at 120 °C for 30 min; styrene, divinylbenzene, azobisisobutyronitrile were mixed, and the modified basic zinc carbonate powder containing hydrogen silicone oil and n-heptane were added to form an oil phase, so that the contents of styrene, divinylbenzene, azobisisobutyronitrile, modified basic zinc carbonate powder containing hydrogen silicone oil and n-heptane in the oil phase were 40 wt%, 14 wt%, 1 wt%, 40 wt% and 5 wt% respectively; 0.01 wt% of hydroxypropyl methyl cellulose was added to deionized water to form an aqueous phase; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and the resin white ball was obtained after polymerization at 80 °C and filtration; the utilization rate of the modified basic zinc carbonate pore former was 94.88% by calculation; the white ball was soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.81 meq / ml.

[0058] Comparative Example 1

[0059] The resin preparation conditions were the same as in Example 1, except that the inorganic pore former was unmodified calcium carbonate powder. Styrene, divinylbenzene, and benzoyl peroxide were mixed, and unmodified calcium carbonate powder and cyclohexane were added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide, unmodified calcium carbonate powder and cyclohexane in the oil phase were 65 wt%, 16 wt%, 0.8 wt%, 10.2 wt% and 8 wt% respectively; 0.05 wt% of hydroxypropyl methyl cellulose and 0.5 wt% of gelatin were added to deionized water to form an aqueous phase; 1 part of the oil phase was added to 4 parts of the aqueous phase under stirring at 300 r / m, and the resin white ball was obtained after polymerization at 80 °C and filtration; a large amount of calcium carbonate powder was found in the aqueous phase after polymerization, and the utilization rate of the modified calcium carbonate pore former was 45.12% by calculation; the white ball was soaked in 5% hydrochloric acid to remove the pore former, and then sulfonated to obtain a porous ion exchange resin. The exchange capacity of the ion exchange resin was 1.77 meq / ml.

[0060] Comparative Example 2

[0061] The resin preparation conditions are the same as those in Example 1, except that the pore-forming agent is an organic pore-forming agent. Styrene, divinylbenzene, benzoyl peroxide are mixed, and cyclohexane is added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide and cyclohexane in the oil phase are 65 wt%, 16 wt%, 0.8 wt% and 18.2 wt%, respectively. Hydroxypropyl methyl cellulose and gelatin are added to deionized water to form an aqueous phase, and the contents are 0.05 wt% and 0.5 wt%, respectively. One part of the oil phase is added to four parts of the aqueous phase under stirring at 300 r / m, and after polymerization at 80°C, the resin white ball is obtained by filtration. The resin white ball is sulfonated, and a porous ion exchange resin is not obtained. It is detected that the resin is a gel-type ion exchange resin.

[0062] Comparative Example 3

[0063] Styrene, divinylbenzene, benzoyl peroxide are mixed, and cyclohexane is added to form an oil phase, so that the contents of styrene, divinylbenzene, benzoyl peroxide and cyclohexane in the oil phase are 40 wt%, 20 wt%, 1 wt% and 39 wt%, respectively. Hydroxypropyl methyl cellulose and gelatin are added to deionized water to form an aqueous phase, and the contents are 0.05 wt% and 0.5 wt%, respectively. One part of the oil phase is added to four parts of the aqueous phase under stirring at 300 r / m, and after polymerization at 80°C, the resin white ball is obtained by filtration. The resin white ball is sulfonated, and a porous ion exchange resin is obtained. It is detected that the exchange capacity of the resin is 1.71 meq / mL. Since only an organic solvent is used as a pore-forming agent, its amount must be greater than the critical value to obtain a porous ion exchange resin. Therefore, a large amount of organic pore-forming agent is required to synthesize a macroporous resin by this method.

Claims

1. A method for synthesizing a porous ion exchange resin, characterized in that: The method includes the following steps: (1) First, the monomer, crosslinking agent, and pore-forming agent are mixed to form an oil phase, and an initiator is added; then the dispersant is dissolved in water to form an aqueous phase; finally, the oil phase and the aqueous phase are mixed to carry out the polymerization reaction; (2) The polymerized product from step (1) is filtered to obtain resin microspheres; (3) The resin microspheres obtained in step (2) are deporinated and sulfonated to obtain the final porous ion exchange resin; Wherein, the monomer mentioned in step (1) is styrene, and the addition amount is 40wt%-70wt%; the crosslinking agent is divinylbenzene, ethylene glycol dimethacrylate or a mixture thereof, and the addition amount is 5%-30wt%; the initiator is benzoyl peroxide and / or azobisisobutyronitrile, and the addition amount is 0.2wt%-1wt%; the addition amount is based on the total mass of monomer, crosslinking agent, porogen and initiator; The porogen mentioned in step (1) includes at least an inorganic porogen, which is a modified lipophilic inorganic porogen. The lipophilic modification process involves contacting the inorganic porogen with a lipophilic reagent to introduce lipophilic groups or lipophilic substances onto the surface of the inorganic porogen. The inorganic porogen is one or a mixture of several of the following: calcium carbonate, magnesium hydroxide, aluminum oxide, aluminum hydroxide, zinc oxide, basic zinc carbonate, and molecular sieve powder. The content of the inorganic porogen is 5wt%-50wt%, based on the total mass of the monomer, crosslinking agent, and initiator.

2. The method according to claim 1, characterized in that: The inorganic pore-forming agent is at least one of calcium carbonate, zinc oxide, and molecular sieve powder.

3. The method according to claim 2, characterized in that: The molecular sieve raw powder is 4A molecular sieve raw powder or 13X molecular sieve raw powder.

4. The method according to claim 1, characterized in that: The particle size of the inorganic porogen is 30-5000 nm.

5. The method according to claim 1, characterized in that: The lipophilic reagent is one or any combination of silicone oil, hydrogen-containing silicone oil, stearic acid, and sodium stearate.

6. The method according to claim 1, characterized in that: The process of lipophilic modification of inorganic porogen is as follows: dissolve the lipophilic reagent in a solvent and mix it thoroughly with the inorganic porogen. Heat the powder obtained after mixing and react to obtain the modified lipophilic inorganic porogen.

7. The method according to claim 6, characterized in that: The reaction temperature is 80-150℃; the reaction time is 5-60 min; the mass ratio of porogen to lipophilic reagent in the material after thorough mixing with the inorganic porogen is 100:5-100:10; and the solvent is one or more of dichloromethane and dichloroethane.

8. The method according to claim 1, characterized in that: The monomer addition amount is 50wt%-65wt%; the crosslinking agent addition amount is 10%-16wt%.

9. The method according to claim 1, characterized in that: The dispersant is one or any mixture of polyvinyl alcohol, gelatin, hydroxypropyl methylcellulose, methylcellulose, hydroxyethyl cellulose, and carboxymethyl cellulose, and the addition amount is 0.01wt%-3wt%, with the above mass based on the mass of the aqueous phase.

10. The method according to claim 1, characterized in that: The mass ratio of the oil phase to the water phase is 1:2 to 1:

5.

11. The method according to claim 1, characterized in that: The polymerization reaction was carried out under stirring and heating conditions, with a stirring rate of 150-400 r / m and a reaction temperature of 60-95 ℃.

12. The method according to claim 1, characterized in that: The removal of pore-forming agents by microspheres is carried out before or simultaneously with sulfonation.

13. A porous ion exchange resin prepared by any one of claims 1-12, characterized in that: The porous ion exchange resin has an exchange capacity of 1.5-2.5 meq / mL.

14. The porous ion exchange resin of claim 13 is used for the removal of heavy metal ions and hardness from water.