High-efficiency phosphorus removal adsorption resin and preparation method thereof

Abstract

The application discloses a kind of high-efficiency phosphorus removal adsorption resin and preparation method thereof, belong to water treatment functional polymer material technical field.The adsorption resin is composed of the following components by weight parts:2-acryloyloxyethyl-3-methyl isoxazolinone 5~25 parts, modified polystyrene copolymer 40~70 parts, crosslinking agent 5~15 parts, hydrophilic regulator 3~10 parts, polymerization initiator 0.5~2 parts and organic solvent 30~80 parts.The resin is constructed by nitrogen-containing heterocyclic acrylate monomer and sulfonated modified polystyrene skeleton copolymerization to build adsorption network, cooperate crosslinking agent to adjust structural stability, hydrophilic regulator improves dispersibility in water, so as to significantly improve the selective adsorption capacity of phosphate and the stability of cyclic use.The adsorption resin preparation process is simple, and the material is environmentally friendly, suitable for sewage deep phosphorus removal multiple scenes, with broad engineering application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment materials, and particularly relates to a high-efficiency phosphorus removal adsorption resin and a preparation method thereof. BACKGROUND

[0002] Water body eutrophication is one of the outstanding environmental problems currently faced by the world, and the core reason is the enrichment of phosphorus in water. As a main limiting nutrient factor, phosphorus is accumulated in agricultural runoff, domestic sewage and part of industrial wastewater for a long time, which leads to the abnormal reproduction of algae in still water bodies such as lakes and reservoirs, frequent water bloom, destroys the balance of the ecological system, and seriously affects the sustainable use of water resources. Studies have shown that even a low phosphorus concentration of 0.02 mg / L is enough to trigger the eutrophication process, so efficient removal of low-concentration phosphorus has become a key technical difficulty in water environment management. At present, the methods for removing phosphorus mainly include chemical precipitation, biological treatment, electrochemical method and adsorption method. Among them, the adsorption method has shown good application prospects in water treatment technology due to its advantages such as simple operation, low energy consumption, strong effluent stability and renewable utilization. However, traditional adsorption materials such as activated alumina, natural zeolite and some resin materials generally have the following problems: limited adsorption capacity, poor selectivity, slow reaction rate, poor mechanical stability and difficulty in regeneration, which restricts their popularization in engineering phosphorus removal applications. In recent years, high molecular functional adsorption resin has become a research hotspot. By grafting functional groups with phosphorus affinity to the polymer skeleton, combined with porous structure design and cross-linked network regulation, the adsorption capacity, reaction rate and material regeneration capacity can be significantly improved. However, the existing resin materials still face the following challenges: insufficient activity of functional groups, uneven distribution, poor structural stability, high cost, and difficulty in balancing performance, economy and industrialization requirements.

[0003] Therefore, it is necessary to develop a high-efficiency adsorption resin material with clear structure, reasonable functional group distribution, simple and controllable preparation process, and high phosphorus selectivity and regeneration capacity, to meet the dual needs of efficient removal of low-concentration phosphorus and sustainable use of materials in modern water environment management. SUMMARY

[0004] In order to overcome the problems of low adsorption capacity, poor selectivity, uneven distribution of functional groups, poor regeneration performance and complex synthesis process of existing adsorption materials in the process of phosphorus removal, the application provides a kind of high-efficiency phosphorus removal adsorption resin and its preparation method, which can realize efficient and selective removal of low-concentration phosphorus in complex water environment, and has good structural stability and renewable ability. The application uses 2-acryloyloxyethyl-3-methyl isoxazolinone as a functional monomer, introduces modified polystyrene copolymer containing sulfonic group as a skeleton material, uses divinylbenzene and trimethylolpropane triacrylate composite crosslinking agent to construct a stable three-dimensional porous structure, at the same time, adds polyethylene glycol methacrylate and acrylamide to form a hydrophilic adjusting phase, uses azobis isobutyronitrile and benzoyl peroxide double initiator to initiate free radical polymerization, and finally obtains spherical adsorption resin material with a particle size of 0.15-0.35 mm. It shows excellent adsorption capacity and selectivity in low-concentration phosphate environment, the material structure is stable and can be repeatedly regenerated, the preparation process is simple and easy to control, the raw material cost is low, and it is suitable for practical engineering application, so it has wide popularization prospect.

[0005] The object of the application can be achieved by the following technical solutions:

[0006] A kind of high-efficiency phosphorus removal adsorption resin, including the following weight parts of components: nitrogen-containing heterocyclic propylene acid ester monomer 5-25 parts, modified polystyrene copolymer 40-70 parts, crosslinking agent 5-15 parts, hydrophilic regulator 3-10 parts, polymerization initiator 0.5-2 parts, organic solvent 30-80 parts;The nitrogen-containing heterocyclic propylene acid ester monomer is 2-acryloyloxyethyl-3-methyl isoxazolinone.

[0007] Optionally, 2-acryloyloxyethyl-3-methyl isoxazolinone is synthesized from the following raw materials by weight: 3-methyl isoxazolinone 10-20 parts, 2-hydroxyethyl acrylate 12-24 parts, p-toluenesulfonic acid 0.3-0.8 parts, hydroquinone 0.01-0.05 parts, anhydrous toluene 40-80 parts.

[0008] Optionally, the modified polystyrene copolymer is composed of the following raw materials by weight: styrene 40-60 parts, divinylbenzene 5-15 parts, chlorosulfonic acid 3-8 parts, dichloromethane 80-150 parts, ice bath water 120-300 parts.

[0009] Optionally, the crosslinking agent is mixed from divinylbenzene and trimethylolpropane triacrylate in a mass ratio of 8:2-9:1;The hydrophilic regulator is mixed from polyethylene glycol methacrylate and acrylamide in a mass ratio of 6:4-7:3;The polymerization initiator is mixed from azobis isobutyronitrile and benzoyl peroxide in a mass ratio of 7:3-8:2;The organic solvent is mixed from ethanol and water in a mass ratio of 3:1-4:1.

[0010] Optionally, the method for preparing 2-acryloyloxyethyl-3-methylisoxazolinone comprises the following steps:

[0011] (a) 3-methylisoxazolinone and 2-hydroxyethyl acrylate are added into anhydrous toluene and mixed uniformly under stirring to form a uniform reaction solution; (b) p-toluenesulfonic acid is added into the uniform reaction solution as an esterification catalyst, and hydroquinone is added as a polymerization inhibitor to prevent free radical self-polymerization of 2-hydroxyethyl acrylate; (c) the reaction system is placed in an 85-90 ℃ oil bath for heating and reflux reaction for 5-7 hours, and byproduct water is continuously removed through a water trap to promote the esterification reaction; (d) after the reaction is completed, the reaction solution is cooled to room temperature, and saturated sodium bicarbonate solution is added to neutralize the residual acidic components in the system; (e) the neutralized reaction mixture is extracted with ethyl acetate, and the organic phase is separated, concentrated by rotary evaporation, and dried under reduced pressure to obtain 2-acryloyloxyethyl-3-methylisoxazolinone product.

[0012] Optionally, the mass ratio of 3-methylisoxazolinone to 2-hydroxyethyl acrylate in step (a) is 1:1.1-1:1.3.

[0013] Optionally, the method for preparing the modified polystyrene copolymer comprises the following steps:

[0014] (1) styrene and divinylbenzene are mixed, emulsifiers and dispersants are added, and suspension polymerization reaction is carried out at 80-90 ℃ for 4-6 hours to prepare spherical polystyrene copolymer microspheres; (2) the spherical polystyrene copolymer microspheres are dispersed in dichloromethane and uniformly suspended under stirring; (3) chlorosulfonic acid is slowly added dropwise under the condition of 0-5 ℃ ice water bath, the reaction temperature is maintained at 0-5 ℃, and sulfonic acid groups are uniformly introduced by continuously stirring the sulfonation reaction for 1-3 hours; (4) after the reaction is completed, ice water is added dropwise to terminate the reaction, and the reaction solution is washed with 1-2% sodium carbonate solution until neutral, and then repeatedly washed with deionized water to remove residual impurities; (5) finally, the obtained solid is filtered and vacuum dried at 50-60 ℃ for 12 hours to obtain the modified polystyrene copolymer.

[0015] Optionally, the mass ratio of styrene to divinylbenzene in step (1) is 4:1-8:1.

[0016] Optionally, a method for preparing a high-efficiency phosphorus removal adsorption resin comprises the following steps:

[0017] S1, 2-acryloyloxyethyl-3-methylisoxazolinone and modified polystyrene copolymer are added to an organic solvent formed by mixing ethanol and water in a mass ratio of 3:1 to 4:1, and stirred at room temperature to make them fully dispersed; S2, crosslinking agent and hydrophilic modifier are sequentially added, and continue to stir for 30 to 60 minutes to form a uniform polymer precursor solution; S3, azobisisobutyronitrile and benzoyl peroxide are added to the polymer precursor solution as polymerization initiators, and free radical polymerization is carried out at 80 to 90°C under a nitrogen atmosphere, and the reaction time is 6 to 10 hours; S4, after the polymerization is completed, it is cooled to room temperature, and solid-liquid separation is carried out, and then washed with anhydrous ethanol and deionized water for 3 to 5 times in sequence to remove unreacted components and impurities; S5, the washed resin is vacuum dried at 50 to 60°C for 12 to 24 hours to obtain high-efficiency phosphorus removal adsorption resin particles with a particle size of 0.15 to 0.35 mm.

[0018] Optionally, the mass ratio of 2-acryloyloxyethyl-3-methylisoxazolinone to modified polystyrene copolymer in step S1 is 1:2 to 1:10.

[0019] The beneficial effects of the present application are:

[0020] The present application introduces 2-acryloyloxyethyl-3-methylisoxazolinone as a functional monomer to construct dense phosphorus affinity sites in the polymer network, enhancing the specific recognition and binding capacity of the resin to phosphate. The nitrogen heterocycle and acyloxy in the structure form a synergistic effect, which can efficiently capture phosphate in water, especially showing excellent adsorption efficiency under low concentration conditions, meeting the technical needs of deep phosphorus removal of drinking water and surface water. The adsorption resin uses modified polystyrene copolymer as the skeleton material, and a stable three-dimensional crosslinked network is constructed by divinylbenzene and trimethylolpropane triacrylate, improving the mechanical strength and structural integrity of the material. Polyethylene glycol methacrylate and acrylamide are introduced as hydrophilic modifiers to effectively improve the wettability and water phase diffusion performance of the resin, speed up the adsorption kinetics process, and improve the phosphorus removal rate and the continuous stability of the resin operation. After multiple adsorption-regeneration cycles, the adsorption capacity retention rate still exceeds 90%, with good reusability. The prepared resin particles have a particle size of 0.15 to 0.35 mm, uniform particle size distribution and good dispersibility, reasonable particle size control helps to reduce the operating resistance, avoid blockage, and improve the system operation efficiency and stability. The material synthesis adopts a free radical polymerization method, the reaction conditions are mild, the process is simple, and the raw materials are widely available. The whole preparation process is controllable, easy to scale up, the product purity is high, the comprehensive preparation cost is low, and it has good industrial application prospect.

[0021] The high-efficiency phosphorus removal adsorption resin has significant advantages in adsorption performance, selectivity, structural stability and renewability, can effectively deal with the treatment demand of phosphorus pollution in complex water environment, and has wide practical application value and popularization potential. BRIEF DESCRIPTION OF DRAWINGS

[0022] The application will be further described below in combination with the drawings.

[0023] Figure 1 It is an infrared spectrum comparison chart of polystyrene copolymer and modified high-efficiency phosphorus removal adsorption resin particles;

[0024] Figure 2 It is a scanning electron microscope photo of the internal structure of the modified high-efficiency phosphorus removal adsorption resin particles;

[0025] Figure 3 It is a comparative fold line chart of the performance of high-efficiency phosphorus removal adsorption resin particles with different proportions. DETAILED DESCRIPTION

[0026] The application will be further described below in combination with the drawings.

[0027] Example 1:

[0028] In this example, 2-acryloyloxyethyl-3-methylisoxazolinone and modified polystyrene copolymer are compounded in a mass ratio of 1:5, and polymerization is carried out under the condition of standard crosslinking agent and hydrophilic regulator ratio, so as to investigate the structural uniformity, particle size control ability and basic phosphorus adsorption capacity of the resin under lower functional monomer content, and provide a reference for subsequent proportion optimization.

[0029] Preparation steps:

[0030] (1) Preparation of 2-acryloyloxyethyl-3-methylisoxazolinone: 3-methylisoxazolinone 10 parts and 2-hydroxyethyl acrylate 12 parts are weighed and added into 40 parts of anhydrous toluene, and mixed under magnetic stirring to form a uniform reaction solution; 0.4 parts of p-toluenesulfonic acid is added as an esterification catalyst, and 0.02 parts of hydroquinone is added as a polymerization inhibitor; the reaction solution is refluxed in an 85°C oil bath for 6 hours, and a water separator is used to continuously remove water to promote the esterification reaction; after the reaction is completed, the temperature is lowered, saturated sodium bicarbonate solution is added to neutralize the acidic components, and then ethyl acetate is used to extract and separate the organic phase, which is rotary evaporated and dried under reduced pressure to obtain a light yellow transparent 2-acryloyloxyethyl-3-methylisoxazolinone product.

[0031] (2) Preparation of modified polystyrene copolymer: 40 parts of styrene and 10 parts of divinylbenzene were mixed, and an appropriate amount of emulsifier and dispersant were added. The mixture was subjected to suspension polymerization at 85°C for 6 hours to obtain spherical copolymer microspheres. The microspheres were dispersed in 100 parts of dichloromethane, and 6 parts of chlorosulfonic acid were slowly added dropwise under 0°C ice-water bath conditions. The mixture was stirred for 1.5 hours to carry out sulfonation reaction. After the reaction was terminated, ice water was added dropwise, the mixture was neutralized with sodium carbonate solution, and the mixture was repeatedly washed with water until neutral. Finally, the mixture was dried under vacuum to obtain the modified polystyrene copolymer with sulfonic acid groups introduced on the surface.

[0032] (3) Take 10 parts of 2-acryloyloxyethyl-3-methylisooxazolinone and 50 parts of modified polystyrene copolymer, add them to 60 parts of organic solvent prepared by mixing ethanol and deionized water, and disperse them under magnetic stirring for 30 minutes to obtain a uniform mixture.

[0033] (4) Add 10 parts of crosslinking agent and 5 parts of hydrophilicity regulator to the homogeneous mixture, and continue stirring for 30 minutes to form a precursor polymerization solution;

[0034] (5) Add 1 part of polymerization initiator and polymerize at 85°C for 8 hours under nitrogen protection;

[0035] (6) After the reaction is complete, cool to room temperature and perform solid-liquid separation. Wash three times with anhydrous ethanol and deionized water respectively to remove unreacted substances and residual impurities.

[0036] (7) The washed resin was placed in a vacuum dryer at 55°C for 18 hours to obtain a high-efficiency phosphorus removal adsorption resin with a particle size of 0.18–0.30 mm.

[0037] Example 2:

[0038] To increase the adsorption site density, the mass ratio of 2-acryloyloxyethyl-3-methylisoxazolinone to the backbone was increased to 1:3 in this embodiment, while keeping the ratio of crosslinking agent to hydrophilic regulator unchanged. The effects of high functional group conditions on the microporous structure, specific surface area and phosphorus removal efficiency of the adsorption resin were observed to verify the positive driving effect of functional monomer concentration on performance.

[0039] Preparation steps:

[0040] (1) Synthesis of 2-acryloyloxyethyl-3-methylisoxazolinone: Take 3-methylisoxazolinone 15 parts and 2-hydroxyethyl acrylate 18 parts, add 60 parts of anhydrous toluene, mix uniformly under magnetic stirring to form a transparent reaction solution; add p-toluenesulfonic acid 0.6 parts as esterification catalyst, and hydroquinone 0.03 parts to inhibit self-polymerization; heat to reflux at 85°C oil bath for 6 hours, continuously remove water with a water trap to promote esterification; after the reaction is completed, cool down, add saturated sodium bicarbonate solution to neutralize residual acidic components; then extract with ethyl acetate, concentrate by rotary evaporation, and finally dry under reduced pressure to obtain the target product as a light yellow transparent liquid.

[0041] (2) Preparation of modified polystyrene copolymer: Mix styrene 45 parts with divinylbenzene 7.5 parts, add appropriate amount of emulsifier and dispersant, and perform suspension polymerization at 85°C for 5 hours to obtain spherical polymer microspheres; disperse the microspheres in 120 parts of dichloromethane, slowly add chlorosulfonic acid 5 parts under 0-5°C ice bath, keep low temperature stirring for 1.5 hours to introduce sulfonic acid groups; after the reaction is completed, add ice water to terminate the reaction, wash with 1.5% sodium carbonate solution until neutral, then wash with deionized water, and finally dry at 55°C under vacuum for 12 hours to obtain surface sulfonated modified polystyrene copolymer.

[0042] (3) Take 2-acryloyloxyethyl-3-methylisoxazolinone 15 parts, modified polystyrene copolymer 45 parts, and add 70 parts of organic solvent mixed with ethanol and deionized water, stir for 30 minutes at room temperature to obtain a uniform dispersion;

[0043] (4) Add crosslinking agent 12 parts, hydrophilic modifier 6 parts, and stir to form the precursor system;

[0044] (5) Add 1.2 parts of initiator, and polymerize at 85°C for 9 hours after nitrogen purging;

[0045] (6) Cool down, collect the product after filtration, and wash with ethanol and water for 3 times;

[0046] (7) The drying condition is 55°C vacuum drying for 20 hours, and the final resin particle size is 0.20-0.32 mm, with BET specific surface area increased to 134 m² / g.

[0047] Example 3:

[0048] In this example, based on the same nitrogen-containing monomer ratio as in Example 2, the proportion of triacrylate in the crosslinking agent is adjusted from 1 / 10 to 1.5 / 10, and the proportion of polyethylene glycol methacrylate in the hydrophilic modifier is increased, aiming to improve the flexibility of the polymer network and the formation efficiency of hydrophilic permeable channels, further enhancing the mass transfer rate and binding capacity of phosphate.

[0049] The polystyrene copolymer in Example 3 was tested by infrared spectroscopy with modified high-efficiency phosphorus removal adsorption resin particles, and the results are shown in Figure 1 The polystyrene copolymer before modification mainly has benzene ring skeleton vibration characteristic absorption peaks at 1600 cm -1 and 1450 cm -1 After modification, a clear carbonyl (C=0) stretching vibration absorption peak appears near 1730 cm -1 , indicating that ester groups are successfully introduced; a strong S=0 stretching vibration peak appears at 1220 cm -1 , indicating that sulfonic acid groups are introduced into the polymer; in addition, C-O-C characteristic absorption peaks appear in the range of 1100-1000 cm -1 , proving that the system contains polyether structure. The above changes fully show that the target functional groups have been successfully grafted onto the polystyrene skeleton, providing abundant complexation sites and hydrophilic properties for the adsorption material, which is conducive to achieving high-efficiency phosphorus removal.

[0050] The scanning diagram can more intuitively show the microstructure of the modified high-efficiency phosphorus removal adsorption resin particles, as shown in Figure 2 .

[0051] Preparation steps:

[0052] (1) Add 2-acryloyloxyethyl-3-methylisoxazolinone 15 parts, modified polystyrene copolymer 45 parts, and ethanol water mixed solvent 70 parts into the mixture, stir at room temperature for 30 minutes;

[0053] (2) Add crosslinking agent 12 parts, hydrophilic modifier 6 parts, and stir for 30 minutes to form a uniform precursor solution;

[0054] (3) The amount of initiator added is 1.2 parts, and the polymerization conditions are 85°C for 8 hours, and the reaction is carried out under nitrogen atmosphere;

[0055] (4) After completion, filter and wash 3 times, and dry at 50°C under vacuum for 24 hours;

[0056] (5) The obtained adsorption resin particle size is 0.17-0.29 mm, and the surface area reaches 142 m² / g.

[0057] Comparative Example 1:

[0058] This comparative example does not add any nitrogen-containing functional monomer, but only uses modified polystyrene copolymer, crosslinking agent and hydrophilic modifier for polymerization, aiming to investigate the physical adsorption capacity of the matrix itself for phosphate, and to compare with the resin of the example, highlighting the important role of 2-acryloyloxyethyl-3-methylisoxazolinone in forming coordination adsorption sites.

[0059] Preparation steps:

[0060] (1) Take 50 parts of modified polystyrene copolymer, add 60 parts of ethanol water mixed solvent and stir evenly;

[0061] (2) Add 10 parts of crosslinking agent and 5 parts of hydrophilic modifier, continue to stir to form a precursor solution;

[0062] (3) Add 1 part of initiator, polymerize at 85°C for 8 hours;

[0063] (4) After reaction, filter, wash and dry (55°C, 18 hours);

[0064] (5) The resulting product has a particle size of 0.22-0.34 mm and a significantly reduced phosphorus adsorption capacity of only 16.2 mg / g.

[0065] Comparative Example 2:

[0066] This comparative example keeps the nitrogen-containing functional monomer unchanged, but replaces the sulfonated skeleton with unmodified ordinary polystyrene microspheres to strip the synergistic effect of sulfonic acid groups, and observes the influence of resin polarity difference on specific surface area, interfacial wettability and phosphate radical fixation effect, further verifying the key role of sulfonation modification in enhancing interfacial hydrophilicity and electronic adsorption force.

[0067] Preparation steps:

[0068] (1) Take 50 parts of ordinary unmodified polystyrene microspheres, 10 parts of 2-acryloyloxyethyl-3-methylisoxazolinone, and 60 parts of ethanol water mixed solvent, stir;

[0069] (2) Add 10 parts of crosslinking agent and 5 parts of hydrophilic modifier, stir for 30 minutes;

[0070] (3) The amount of initiator added is 1 part, the reaction condition is 85°C, and the polymerization time is 8 hours;

[0071] (4) After cooling, filter, wash and dry, the temperature is 55°C, and the time is 18 hours;

[0072] (5) The final product has a particle size of 0.25-0.40 mm and a decreased phosphorus adsorption capacity with a maximum adsorption capacity of 26.5 mg / g.

[0073] Performance test

[0074] Phosphorus adsorption capacity test

[0075] Adsorption experiment with simulated phosphorus-containing wastewater: 100 mL of phosphate solution (prepared with KH2PO4) with an initial concentration of 50 mg / L was added to a 250 mL conical flask, and the pH was adjusted to 6.5; 0.2 g of dry weight of the adsorbent resin sample was added, and placed in a constant temperature oscillator (150 rpm, 25°C) for oscillation for 24 hours; after the adsorption was completed, the residual phosphate concentration in the filtrate was determined by filtering with a 0.45 μm filter membrane, and the residual phosphate concentration in the filtrate was determined by the ammonium molybdate spectrophotometric method at a wavelength of 880 nm; the phosphorus adsorption capacity (mg / g) was calculated according to the concentration difference before and after adsorption.

[0076] Specific surface area and pore size test (BET method)

[0077] The samples were dried under vacuum, and the BET specific surface area and average pore size distribution were determined using a specific surface area analyzer (N2 adsorption-desorption method); the correlation between the adsorption performance and the pore structure parameters of the material was analyzed.

[0078] Regeneration and recycling performance

[0079] After the resin sample was saturated with adsorption, it was eluted with 0.1 mol / L NaOH solution, and then neutralized and washed with deionized water; after vacuum drying, the next round of adsorption experiment was performed, and the adsorption capacity retention rate was calculated after 5 cycles to evaluate the regeneration stability.

[0080] Resin particle size and dispersity evaluation

[0081] The particle size distribution of the sample was determined using an optical microscope combined with a laser particle size analyzer, and the dispersion state and sedimentation behavior in a static water system were observed; combined with the actual use scenario, it was determined whether the material had good mixing and distribution ability.

[0082] Table 1 Performance test results of adsorbent resin samples

[0083] Sample Particle size range (mm) Specific surface area (m2 / g) Maximum phosphorus adsorption capacity (mg / g) Adsorption capacity retention rate (%) Example 1 0.18–0.30 126 48.7 91.2 Example 2 0.20–0.32 134 52.4 93.7 Example 3 0.17–0.29 142 56.8 95.1 Comparative Example 1 0.22–0.34 89 16.2 66.4 Comparative Example 2 0.25–0.40 95 26.5 71.3

[0084] According to the table and Figure 3 As shown in the table and

[0085] In terms of recycling performance, the adsorption capacity retention rate of the product of the embodiment can still be maintained at 91.2% to 95.1% after 5 adsorption-desorption cycles, while the retention rates of Comparative Example 1 and Comparative Example 2 are reduced to 66.4% and 71.3%, respectively. This shows that the adsorption resin prepared by the application has good structural stability and reversible adsorption performance, is suitable for continuous recycling in industrial scenarios, and has strong potential for recycling.

[0086] The specific surface area test results show that the specific surface areas of Examples 1, 2 and 3 are 126 m² / g, 134 m² / g and 142 m² / g, respectively, which are much higher than 89 m² / g of Comparative Example 1 and 95 m² / g of Comparative Example 2. The increase in specific surface area is conducive to providing more active sites and enhancing adsorption efficiency. In particular, Example 3, by adjusting the hydrophilic component and crosslinking density, further promotes the formation of microporous structure, thereby significantly improving the overall adsorption performance.

[0087] In terms of particle size control and dispersibility, the particle size distribution of the product of the embodiment is concentrated between 0.17 and 0.32 mm, the particles are uniform and of moderate size, have good dispersion stability and water suspension, and are conducive to maintaining efficient liquid-solid contact during actual operation. The particle size of the non-sulfonated polystyrene microspheres used in Comparative Example 2 is large, reaching 0.25 to 0.40 mm, and is prone to agglomeration and sedimentation, affecting its actual application effect.

[0088] In summary, the adsorption resin material designed by the application has significant advantages in terms of adsorption capacity, regeneration stability, pore structure and dispersibility, especially the comprehensive performance of Example 3 is the best. The above results fully prove that the adsorption resin structure constructed by using nitrogen-containing heterocyclic functional monomers and sulfonated polystyrene skeleton can effectively improve the phosphorus removal capacity, and has good application prospect and popularization value.

Claims

1. A high-efficiency phosphorus removal adsorption resin, characterized in that, The product comprises the following components by weight: 5-25 parts of nitrogen-containing heterocyclic acrylate monomers, 40-70 parts of modified polystyrene copolymer, 5-15 parts of crosslinking agent, 3-10 parts of hydrophilicity modifier, 0.5-2 parts of polymerization initiator, and 30-80 parts of organic solvent. The modified polystyrene copolymer is obtained by suspension polymerization of styrene and divinylbenzene at 80-90°C for 4-6 hours under the action of an emulsifier and dispersant to obtain spherical copolymer microspheres. The microspheres are dispersed in dichloromethane, and chlorosulfonic acid is slowly added dropwise at 0-5°C, followed by sulfonation with stirring for 1-3 hours. After the reaction is complete, ice water is added dropwise to terminate the reaction. The product is washed successively with sodium carbonate solution and deionized water until neutral, and finally vacuum dried at 50-60°C for 12 hours to obtain the modified polystyrene copolymer. The hydrophilicity modifier is composed of polyethylene glycol methacrylate and acrylamide in a mass ratio of 6:4-7:

3. Mixing; The high-efficiency phosphorus removal adsorption resin particles are prepared by adding 2-acryloyloxyethyl-3-methylisooxazolinone and modified polystyrene copolymer to an organic solvent formed by mixing ethanol and water in a mass ratio of 3:1 to 4:1, and stirring at room temperature to ensure full dispersion; then adding a crosslinking agent and a hydrophilicity regulator in sequence, and continuing to stir for 30 to 60 minutes to form a uniform polymerization precursor solution; adding azobisisobutyronitrile and benzoyl peroxide as polymerization initiators to the polymerization precursor solution, and carrying out a free radical polymerization reaction at 80 to 90°C under a nitrogen atmosphere for 6 to 10 hours; after polymerization, cooling to room temperature, performing solid-liquid separation, and washing with anhydrous ethanol and deionized water 3 to 5 times in sequence to remove unreacted components and impurities; and then vacuum drying the washed resin at 50 to 60°C for 12 to 24 hours to obtain a particle size of 0.15 to 0.35 mm.

2. The high-efficiency phosphorus removal adsorption resin according to claim 1, characterized in that, The 2-acryloyloxyethyl-3-methylisooxazolinone is synthesized from the following raw materials in parts by weight: 10-20 parts of 3-methylisooxazolinone, 12-24 parts of 2-hydroxyethyl acrylate, 0.3-0.8 parts of p-toluenesulfonic acid, 0.01-0.05 parts of hydroquinone, and 40-80 parts of anhydrous toluene.

3. The high-efficiency phosphorus removal adsorption resin according to claim 1, characterized in that, The modified polystyrene copolymer is composed of the following raw materials in parts by weight: 40-60 parts styrene, 5-15 parts divinylbenzene, 3-8 parts chlorosulfonic acid, 80-150 parts dichloromethane, and 120-300 parts ice bath water.

4. The high-efficiency phosphorus removal adsorption resin according to claim 1, characterized in that, The crosslinking agent is a mixture of divinylbenzene and trimethylolpropane triacrylate in a mass ratio of 8:2 to 9:1; the hydrophilicity modifier is a mixture of polyethylene glycol methacrylate and acrylamide in a mass ratio of 6:4 to 7:3; the polymerization initiator is a mixture of azobisisobutyronitrile and benzoyl peroxide in a mass ratio of 7:3 to 8:2; and the organic solvent is a mixture of ethanol and water in a mass ratio of 3:1 to 4:

1.

5. The high-efficiency phosphorus removal adsorption resin according to claim 1 or 2, characterized in that, The preparation method of the 2-acryloyloxyethyl-3-methylisoxazolinone is as follows: 3-Methylisoxazolinone and 2-hydroxyethyl acrylate were added to anhydrous toluene and stirred. After adding p-toluenesulfonic acid and hydroquinone, the mixture was refluxed at 85–90 °C for 5–7 hours, and the esterification reaction was continuously promoted by dehydration using a water separator. After the reaction was completed, the mixture was cooled, the residual acidic components were neutralized, and the mixture was extracted with ethyl acetate, rotary evaporated, and dried under reduced pressure to obtain 2-acryloyloxyethyl-3-methylisoxazolinone.

6. The high-efficiency phosphorus removal adsorption resin according to claim 5, characterized in that, In the preparation method described above, the mass ratio of 3-methylisoxazolinone to 2-hydroxyethyl acrylate is 1:1.1 to 1:1.

3.

7. The high-efficiency phosphorus removal adsorption resin according to claim 1 or 3, characterized in that, The method for preparing the modified polystyrene copolymer is as follows: Styrene and divinylbenzene were subjected to suspension polymerization at 80–90 °C for 4–6 hours under the action of emulsifier and dispersant to obtain spherical copolymer microspheres. The microspheres were dispersed in dichloromethane, and chlorosulfonic acid was slowly added dropwise at 0–5 °C, followed by stirring and sulfonation for 1–3 hours. After the reaction was completed, ice water was added dropwise to terminate the reaction. The mixture was washed successively with sodium carbonate solution and deionized water until neutral, and finally vacuum dried at 50–60 °C for 12 hours to obtain the modified polystyrene copolymer.

8. The high-efficiency phosphorus removal adsorption resin according to claim 7, characterized in that, In the preparation method, the mass ratio of styrene to divinylbenzene is 4:1 to 8:

1.

9. A method for preparing a high-efficiency phosphorus removal adsorption resin, characterized in that, Includes the following steps: S1, 2-Acryloyloxyethyl-3-methylisoxazolinone and modified polystyrene copolymer are added to an organic solvent formed by mixing ethanol and water in a mass ratio of 3:1 to 4:1, and stirred at room temperature to disperse them fully; S2, add crosslinking agent and hydrophilic regulator in sequence, and continue stirring for 30 to 60 minutes to form a homogeneous polymerization precursor solution; S3, Azobisisobutyronitrile and benzoyl peroxide are added to the polymerization precursor solution as polymerization initiators, and free radical polymerization is carried out under nitrogen atmosphere at 80-90°C for 6-10 hours. S4. After polymerization, cool to room temperature and perform solid-liquid separation. Wash with anhydrous ethanol and deionized water 3 to 5 times in sequence to remove unreacted components and impurities. S5. The washed resin is vacuum dried at 50-60°C for 12-24 hours to obtain high-efficiency phosphorus removal and adsorption resin particles with a particle size of 0.15-0.35 mm.

10. The method for preparing a high-efficiency phosphorus removal adsorption resin according to claim 9, characterized in that, In step S1, the mass ratio of 2-acryloyloxyethyl-3-methylisoxazolinone to the modified polystyrene copolymer is 1:2 to 1:10.

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