Disclosure of Invention
The invention aims to solve the technical problems of overcoming the defects of the prior art and providing the magnetic polydivinylbenzene microsphere resin which has the advantages of large specific surface area, narrow particle size distribution, good balling performance, high reusability, capability of efficiently removing nitrobenzene compounds and excellent adsorption performance; also provides a preparation method of the magnetic polydivinylbenzene microsphere resin, which has the advantages of simple operation, short process flow, short time consumption, simple raw materials and low cost.
In order to solve the technical problems, the invention adopts the following technical scheme:
the magnetic polydivinylbenzene microsphere resin comprises a polydivinylbenzene microsphere resin framework and magnetic particles, wherein the magnetic particles are uniformly distributed in the polydivinylbenzene microsphere resin framework, and the specific surface area of the magnetic polydivinylbenzene microsphere resin is 800m2/g~1200m2/g。
As a general disclosure, the present invention also provides a method for preparing magnetic polydivinylbenzene microsphere resin, comprising the following steps:
s1, dissolving a dispersing agent in water, wherein the dispersing agent is a mixture containing gelatin, trisodium phosphate and disodium hydrogen phosphate to obtain a dispersion liquid;
s2, adding oleic acid, succinic acid or fluoroether acid modified magnetic particles, divinylbenzene, a pore-forming agent and an initiator into the dispersion liquid, uniformly mixing, and then carrying out polymerization reaction;
and S3, after the reaction is finished, cleaning and drying a product obtained by the polymerization reaction to obtain the magnetic polydivinylbenzene microsphere resin.
In the above method for preparing magnetic polydivinylbenzene microsphere resin, preferably, in S2, the method for preparing magnetic particles modified with oleic acid, succinic acid or fluoroether acid comprises: activating magnetic particles by using ethanol or methanol, adding ammonia water and the activated magnetic particles into water to obtain alkaline mixed liquid, adding an organic solvent dissolved with oleic acid, succinic acid or fluoroether acid into the mixed liquid, stirring and modifying the mixed liquid, adjusting the pH value to 6-8 after modification is finished, separating the magnetic particles, cleaning and drying the obtained magnetic particles to obtain the modified magnetic particles.
In the above preparation method of the magnetic polydivinylbenzene microsphere resin, preferably, in S1, the addition amount of the dispersant is 1.6-14.5% of the mass of water; in the dispersing agent, the mass ratio of the gelatin to the trisodium phosphate to the disodium hydrogen phosphate is (1-3) to 1 to (2-5); the concentration of the trisodium phosphate in the obtained dispersion liquid is 2 g/L-8 g/L.
In the above preparation method of the magnetic polydivinylbenzene microsphere resin, preferably, in S2, the temperature of the polymerization reaction is 60 ℃ to 120 ℃; the time of the polymerization reaction is 6-24 h.
In the above method for preparing a magnetic polydivinylbenzene microsphere resin, preferably, the S1 further comprises a step of adding sodium chloride to the dispersion; the mass of the sodium chloride is 5-20% of the mass of the water.
In the above method for preparing magnetic polydivinylbenzene microsphere resin, preferably, in S2, the magnetic particles are iron oxide Fe3O4、γ-Fe2O3At least one of an oxide of nickel or an oxide of cobalt; the particle size of the magnetic particles is 5 nm-20 nm; the dosage of the magnetic particles is 1-10% of the mass of the divinylbenzene.
In the preparation method of the magnetic polydivinylbenzene microsphere resin, preferably, the dosage of the oleic acid, the succinic acid or the fluoroether acid is 1-10 times of the mass of the magnetic particles;
the concentration of the ammonia water is 25-28 wt.%; the volume ratio of the ammonia water to the water is 1: 50-100.
In the above preparation method of magnetic polydivinylbenzene microsphere resin, preferably, in S2, the pore-forming agent is at least one of cyclohexanol, pentanol, toluene, xylene, dodecanol, heptane and isooctane; the addition amount of the pore-foaming agent is 10-500% of the mass of the divinylbenzene;
in the above preparation method of the magnetic polydivinylbenzene microsphere resin, preferably, the initiator is benzoyl peroxide and/or azobisisobutyronitrile; the addition amount of the initiator is 0.5-8% of the mass of the divinylbenzene.
As a general inventive concept, the invention also provides the magnetic polydivinylbenzene microsphere resin or the magnetic polydivinylbenzene microsphere resin prepared by the preparation method, which is used for adsorbing nitrobenzene compounds.
Compared with the prior art, the invention has the advantages that:
1. the magnetic polydivinylbenzene microsphere resin disclosed by the invention is good in balling property, large in specific surface area, narrow in particle size distribution, high in reusability, capable of efficiently removing nitrobenzene compounds and excellent in adsorption performance.
2. According to researches, the invention adopts a specific mixed dispersant, takes a single cross-linking agent, namely divinylbenzene, as a monomer raw material, adds the modified magnetic particles, and carries out polymerization reaction to prepare the magnetic polydivinylbenzene microsphere resin with good balling property, high specific surface area and narrow particle size distribution. The preparation method has the advantages of short process flow, short time consumption and low cost, simplifies the preparation procedure, and improves the specific surface area and the utilization rate of the benzene ring.
3. The invention adopts a specific process to modify the finished magnetic particle product, can modify in large scale, saves the process time, reduces the cost and has excellent modification effect.
4. The magnetic polydivinylbenzene microsphere resin disclosed by the invention has good adsorption performance on nitrobenzene compounds, can effectively remove nitrobenzene pollutants in water, and has important application value in the fields of adsorption separation such as organic chemical wastewater treatment and the like. The adsorption capacity of the magnetic polydivinylbenzene microsphere resin of the invention to 2-nitrotoluene, 2, 4-dinitrotoluene and 2,4, 6-trinitrotoluene can reach 394mg/g, 329mg/g and 244mg/g respectively.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples.
A preparation method of magnetic polydivinylbenzene microsphere resin comprises the following steps:
(1) modification of magnetic particles: the purpose of this step is to utilize the magnetic metal oxide nano-particles modified by lipophilic organic substances as magnetic cores. And (3) refluxing the magnetic nanoparticles with ethanol or methanol at 60-100 ℃ for 10-120 min, and drying to activate and clean the magnetic particles. Adding the dried magnetic nanoparticles into a three-neck round-bottom flask which is dropwise added with ammonia water and is filled with deionized water, wherein the concentration of the ammonia water is 25-28 wt.%; the volume ratio of the ammonia water to the deionized water is 1: 50-100. Adjusting the stirring speed to 200-1000 rpm, introducing nitrogen or argon into the solution to remove dissolved oxygen in the solution, then raising the temperature to 60-120 ℃ in a nitrogen or argon environment, dripping one of oleic acid, succinic acid or fluoroether acid dissolved in one of organic solvents such as acetone, ethanol or methanol into the mixed solution, reacting for 10-120 min, dripping one of oleic acid, succinic acid and fluoroether acid again to perform secondary complementary modification on the surface of the magnetic nano-particles, and continuing to react for 10-120 min. And after cooling, adjusting the pH value of the mixed solution to 6-8 by using hydrochloric acid or sulfuric acid, separating the modified magnetic material particles by using a magnet, washing by using methanol, and drying in vacuum. Wherein the nano magnetic particles are Fe3O4、γ-Fe2O3And nanoparticles having good magnetic properties such as nickel oxide and cobalt oxide.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin: one or more of o-divinylbenzene, m-divinylbenzene and p-divinylbenzene are taken as monomer raw materials, one or more of cyclohexanol, amyl alcohol, toluene, xylene, dodecanol, heptane and isooctane are taken as pore-forming agents, a mixture of gelatin, trisodium phosphate and disodium hydrogen phosphate is taken as a dispersing agent, sodium chloride can be added to reduce the solubility of the monomers in water, benzoyl peroxide and azodiisobutyronitrile are taken as initiators, a suspension polymerization method is adopted to carry out polymerization reaction to prepare the divinylbenzene polymer, the temperature of the polymerization reaction is 60-120 ℃, the time of the polymerization reaction is 6-24 h, the stirring speed of the polymerization reaction is 200-1000 rpm, distilled water, ethanol and acetone are selected to carry out repeated washing to remove the pore-forming agents and residual dispersing agents, organic matters and inorganic salts, and the magnetic polydivinylbenzene microsphere resin is obtained by drying.
The magnetic particles being Fe3O4、γ-Fe2O3Nickel oxide, cobalt oxide; the particle size of the magnetic particles is 5 nm-20 nm; the dosage of the magnetic material particles is 1-10% of the mass of the monomer.
The pore-foaming agent is one or more of cyclohexanol, amyl alcohol, toluene, xylene, dodecanol, heptane and isooctane, preferably toluene, xylene or heptane, and the adding amount of the pore-foaming agent is 10-500%, preferably 150-200% of the mass of divinylbenzene.
The addition amount of the initiator is 0.5 to 8 percent of the mass of the monomer.
The addition amount of the dispersant is 1.6-14.5% of the mass of the deionized water and is 20-40% of the mass of the monomer; in the dispersing agent, the mass ratio of gelatin to trisodium phosphate to disodium hydrogen phosphate is (1-3) to 1 to (2-5), and the concentration of trisodium phosphate is 2-8 g/L. Wherein the disodium hydrogen phosphate is Na2HPO4·12H2O。
The using amount of the oleic acid, the succinic acid or the fluoroether acid is 1-10 times of the mass of the magnetic particles;
the adding amount of the sodium chloride is 5-20% of the mass of the deionized water.
The temperature of the polymerization reaction is preferably 80 ℃ to 95 ℃, and the time of the polymerization reaction is preferably 6h to 12 h.
The obtained magnetic polydivinylbenzene microsphere resin contains a large number of benzene ring structures, and has high specific surface area, the particle size is preferably 100-200 mu m, and the specific surface area is 800m2/g~1200m2A value of/g, for example, 800 to 900m2/g。
The magnetic polydivinylbenzene microsphere resin mainly has a benzene ring structure, so that adsorption can be realized through pi-pi action between the resin and nitrobenzene compounds, and hydrophobic adsorption can also be realized through hydrophobic property of a resin skeleton and hydrophobic parts of the nitrobenzene compounds. The invention can effectively utilize the bridging bond generated by divinylbenzene in the reaction to increase the number of pore channels and increase the specific surface area of the resin.
Example 1
The invention relates to a preparation method of magnetic polydivinylbenzene microsphere resin, which comprises the following steps:
(1) synthesis of oil-soluble magnetic material:
mixing nano magnetic Fe3O4Refluxing with 100mL of ethanol at 80 deg.C for 30min, cooling and drying. Drying 5g of magnetic Fe3O4Adding the mixture into a 500mL three-neck flask containing 250mL deionized water dropwise added with 2.5mL ammonia water (25 wt.% to 28 wt.%), adjusting the stirring speed to 450rpm, introducing nitrogen, stirring for 30min, removing dissolved oxygen in water, raising the temperature to 85 ℃, adding 25mL acetone dissolved with 5g oleic acid dropwise, reacting for 10min, adding 5g oleic acid dropwise, and adopting a mode of modifying magnetic nanoparticles for multiple times to ensure that the modification effect is better, and continuing to react for 30 min. Cooling, adjusting pH of the mixed solution to 7 with hydrochloric acid, removing self-assembly of modified particles, settling, and adding magnet to magnetic Fe3O4The particles were separated, washed with methanol and dried under vacuum.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin:
s1, mixing 4g of gelatin, 2g of trisodium phosphate and 10g of Na2HPO4·12H2Dissolving O in 500mL of ionized water to serve as a dispersed phase, adding 70g of sodium chloride into the dispersed phase, and then placing the mixture into a 1000mL three-neck round-bottom flask;
s2, adding 50g of p-divinylbenzene and 5g of oleic acid modified Fe into a three-neck round-bottom flask3O4An oil phase consisting of the particles, 125g of toluene and 1g of benzoyl peroxide was stirred at a stirring speed of 400rpm, gradually heated to 95 ℃ for polymerization, and discharged after 12 hours.
S3, after the reaction system is cooled, separating the prepared magnetic copolymer from the reaction system by using a magnet, washing the copolymer for 3-5 times by using deionized water, washing the copolymer for 2 times by using ethanol, washing the copolymer for 1 time by using acetone, and drying the copolymer for 8 hours in vacuum at the temperature of 60 ℃, wherein the obtained resin is the magnetic polydivinylbenzene microsphere resin.
Example 2
The invention relates to a preparation method of magnetic polydivinylbenzene microsphere resin, which comprises the following steps:
(1) synthesis of oil-soluble magnetic material:
nano magnetic gamma-Fe2O3Refluxing with 100mL of ethanol at 80 deg.C for 30min, cooling and drying. Taking dried 5g of magnetic gamma-Fe2O3Adding a 500mL three-neck flask containing 250mL of deionized water dropwise added with 2.5mL of ammonia water (25 wt.% to 28 wt.%), adjusting the stirring speed to 450rpm, introducing nitrogen, stirring for 30min, removing dissolved oxygen in water, raising the temperature to 85 ℃, dropwise adding 25mL of acetone dissolved with 5g of oleic acid, reacting for 10min, dropwise adding 5g of oleic acid, and continuing to react for 30 min. After cooling, the pH of the mixed solution was adjusted to 7 with hydrochloric acid, and then magnetic γ -Fe was aligned using a magnet2O3The particles were separated, washed with methanol and dried under vacuum.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin:
s1, mixing 4g of gelatin, 2g of trisodium phosphate and 8g of Na2HPO4·12H2O was dissolved in 500mL of deionized water as a dispersed phase, and 70g of sodium chloride was added to the dispersed phase, which was then placed in a 1000mL three-necked round-bottomed flask.
S2, adding 50g of o-divinylbenzene and 5g of oleic acid modified gamma-Fe into a three-neck round-bottom flask2O3An oil phase consisting of the particles, 125g of xylene and 1g of benzoyl peroxide is stirred at a stirring speed of 400rpm, the temperature is gradually increased to 95 ℃, polymerization reaction is carried out, and discharging is carried out after 12 hours.
S3, after the reaction system is cooled, separating the prepared magnetic copolymer from the reaction system by using a magnet, washing the copolymer for 3-5 times by using deionized water, washing the copolymer for 2 times by using ethanol, washing the copolymer for 1 time by using acetone, and drying the copolymer for 8 hours in vacuum at the temperature of 60 ℃, wherein the obtained resin is the magnetic polydivinylbenzene microsphere resin.
Comparative example 1
A preparation method of magnetic polydivinylbenzene microsphere resin comprises the following steps:
(1) synthesis of oil-soluble magnetic material:
mixing nano magnetic Fe3O4Through 100Refluxing in mL ethanol at 80 deg.C for 30min, cooling and drying. Taking 5g of dried magnetic Fe3O4Adding a 500mL three-neck flask containing 250mL of deionized water dropwise added with 2.5mL of ammonia water (25 wt.% to 28 wt.%), adjusting the stirring speed to 450rpm, introducing nitrogen, stirring for 30min, removing dissolved oxygen in water, raising the temperature to 85 ℃, dropwise adding 25mL of acetone dissolved with 5g of oleic acid, reacting for 10min, dropwise adding 5g of oleic acid, and continuing to react for 30 min. After cooling, the mixed solution was adjusted to pH 7 with hydrochloric acid, and then magnetic Fe was aligned using a magnet3O4The particles were separated, washed with methanol and dried under vacuum.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin:
s1, 2g of polyvinyl alcohol was dissolved in 500mL of deionized water as a dispersed phase, and the dispersed phase was charged into a 1000mL three-necked round bottom flask.
S2, adding 50g of o-divinylbenzene and 5g of oleic acid modified Fe into a three-neck round-bottom flask3O4An oil phase consisting of the particles, 125g of dodecanol and 1g of benzoyl peroxide was stirred at a stirring speed of 400rpm, gradually heated to 95 ℃ for polymerization, and discharged after 12 hours.
And S3, after the reaction system is cooled, separating the prepared magnetic copolymer from the reaction system by using a magnet, washing the magnetic copolymer for 3-5 times by using deionized water, washing the magnetic copolymer for 2 times by using ethanol, and washing the magnetic copolymer for 1 time by using acetone. Vacuum drying at 60 deg.c for 8 hr to obtain magnetic polydivinylbenzene microballoon resin.
In the comparative example, in the actual preparation process, when the same amount of sodium chloride was added, the magnetic polydivinylbenzene microsphere resin with good spheronization could not be obtained.
In this comparative example, in the actual preparation process, when the amount of the polyvinyl alcohol is too large, the magnetic polydiethylene microsphere resin with good spheronization cannot be obtained, and this comparative example is an example in which the addition amount of the polyvinyl alcohol is preferable.
Comparative example 2
A preparation method of magnetic polydivinylbenzene microsphere resin comprises the following steps:
(1) synthesis of oil-soluble magnetic material:
mixing nano magnetic Fe3O4Refluxing with 100mL of ethanol at 80 deg.C for 30min, cooling and drying. Taking 5g of dried magnetic Fe3O4Adding a 500mL three-neck flask containing 250mL of deionized water dropwise added with 2.5mL of ammonia water (25 wt.% to 28 wt.%), adjusting the stirring speed to 450rpm, introducing nitrogen, stirring for 30min, removing dissolved oxygen in water, raising the temperature to 85 ℃, dropwise adding 25mL of acetone dissolved with 5g of oleic acid, reacting for 10min, dropwise adding 5g of oleic acid, and continuing to react for 30 min. After cooling, the pH of the mixed solution obtained after the reaction was adjusted to 7 with hydrochloric acid, and then magnetic Fe was magnetized using a magnet3O4The particles were separated, washed with methanol and dried under vacuum.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin:
s1, 0.6g of nonylphenol polyoxyethylene ether and 1.2g of polyvinyl alcohol were dissolved in 500mL of deionized water as a dispersed phase. The dispersed phase was placed in a 1000mL three-necked round bottom flask.
S2, adding 50g of p-divinylbenzene and 5g of oleic acid modified Fe into a three-neck round-bottom flask3O4An oil phase consisting of the particles, 125g of toluene and 1g of benzoyl peroxide was stirred at a stirring speed of 400rpm, gradually heated to 95 ℃ for polymerization, and discharged after 12 hours.
And S3, after the reaction system is cooled, separating the prepared magnetic copolymer from the reaction system by using a magnet, washing the magnetic copolymer for 3-5 times by using deionized water, washing the magnetic copolymer for 2 times by using ethanol, and washing the magnetic copolymer for 1 time by using acetone. Vacuum drying at 60 deg.c for 8 hr to obtain magnetic polydivinylbenzene microballoon resin.
In the comparative example, in the actual preparation process, when sodium chloride is added, the magnetic polydivinylbenzene microsphere resin with good balling property cannot be obtained.
In this comparative example, in the actual preparation process, when the amounts of nonylphenol polyoxyethylene ether and polyvinyl alcohol were too large, a magnetic polydivinylbenzene microsphere resin with good spheronization could not be obtained.
Comparative example 3
A preparation method of magnetic polydivinylbenzene microsphere resin comprises the following steps:
(1) synthesis of oil-soluble magnetic material:
mixing nano magnetic Fe3O4Refluxing with 100mL of ethanol at 80 deg.C for 30min, cooling and drying. Drying, and mixing 5g of magnetic Fe3O4Adding the mixture into a 500mL three-neck flask containing 250mL deionized water dropwise added with 2.5mL ammonia water (25 wt.% to 28 wt.%), adjusting the stirring speed to 450rpm, introducing nitrogen, stirring for 30min, removing dissolved oxygen in water, raising the temperature to 85 ℃, adding 25mL acetone dissolved with 5g oleic acid dropwise, reacting for 10min, adding 5g oleic acid dropwise, and continuing to react for 30 min. After cooling, the pH of the mixed solution obtained after the reaction was adjusted to 7 with hydrochloric acid, and then magnetic Fe was magnetized using a magnet3O4The particles were separated, washed with methanol and dried under vacuum.
(2) Synthesizing magnetic polydivinylbenzene microsphere resin:
s1, 8g of gelatin was dissolved in 500mL of deionized water as a dispersed phase, and the dispersed phase was placed in a 1000mL three-necked round bottom flask.
S2, adding 50g of m-divinylbenzene and 5g of oleic acid modified Fe into a three-neck round-bottom flask3O4An oil phase consisting of the particles, 125g of toluene and 1g of benzoyl peroxide was stirred at a stirring speed of 400rpm, gradually heated to 95 ℃ for polymerization, and discharged after 12 hours.
S3, after the reaction system is cooled, separating the prepared magnetic copolymer from the reaction system by using a magnet, washing the copolymer for 3-5 times by using deionized water, washing the copolymer for 2 times by using ethanol, washing the copolymer for 1 time by using acetone, and drying the copolymer for 8 hours in vacuum at the temperature of 60 ℃, wherein the obtained resin is the magnetic polydivinylbenzene microsphere resin.
In the comparative example, in the actual preparation process, when sodium chloride is added, the magnetic polydivinylbenzene microsphere resin with good balling property cannot be obtained.
In the comparative example, in the actual preparation process, when the amount of gelatin is too much, the magnetic polydivinylbenzene microsphere resin with good balling property cannot be obtained, and the comparative example is an example with a better gelatin adding amount.
Example 1 Fe before modification with oleic acid3O4Modified Fe3O4The IR contrast with oleic acid is shown in FIG. 1, where Fe is present in FIG. 13O4At a wave number of 546cm-1Has a strong vibration absorption peak belonging to Fe3O4Characteristic peak of (2). Oleic acid modified O-Fe3O4The wave number of the particles is 2971cm-1And 2877cm-1In this case, the-CH of the weak oleic acid molecule appears3and-CH2A stretching vibration peak; at wave number of 3381cm-1Is Fe3O4Stretching vibration peak of-OH on the surface of nanoparticle, 538cm-1Strong absorption peak at (C) relative to Fe3O4At 546cm-1The characteristic peak of the resin microsphere is shifted to a certain extent, because the mutual action between COO-Fe influences the bond energy of Fe-O bonds, the oleic acid successfully modifies the magnetic particles, so that lipophilic long-chain alkyl groups are wrapped on the surfaces of the magnetic particles, the magnetic particles can be well fused with organic phases, and the magnetic particles can be uniformly dispersed in the polymerization process of the resin microsphere and well dispersed in the resin microsphere.
FIG. 2 shows Fe before modification with oleic acid in example 13O4O-Fe obtained by modification with oleic acid3O4XRD contrast pattern of (a). The figure has 6 characteristic peaks such as (220), (311), (400), (422), (511), (440), and the like, and the comparative map of figure 2 shows that O-Fe modified by oleic acid3O4Diffraction peak and Fe3O4The positions of (a) and (b) are consistent, indicating that the surface-modified magnetic particles do not cause structural changes. FIG. 3 is Fe before modification with oleic acid in example 13O4O-Fe obtained by modification with oleic acid3O4Hysteresis loop comparison of (1), Fe in FIG. 33O4And oleic acid modified O-Fe3O4The specific saturation magnetization is 64.11emu/g and 49.66emu/g respectively, as can be seen from figure 3, hysteresis loops do not appear before and after modification, which shows that the obtained material has no remanence and superparamagnetism, and the oleic acid modified O-Fe3O4The specific saturation magnetization of the particles decreased by 22.54%,the reason for this is probably that the mass of the magnetic nanoparticles in unit mass is reduced due to the existence of the oleic acid coating layer, so that the phenomenon of reduction of saturation magnetization is generated, which indicates that the modification is successful, and the successfully modified magnetic material can be better applied to the polymerization of resin microspheres, so that the resin can be collected by using a magnet in subsequent use.
FIG. 4 is an infrared contrast chart of divinylbenzene and magnetic polydivinylbenzene microsphere resin prepared in example 1 of the present invention. Divinylbenzene 1630cm-1In the form of-CH ═ CH2The infrared spectrogram of the magnetic polydivinylbenzene microsphere resin is weakened, and the success of the synthesis of the magnetic polydivinylbenzene microsphere resin is judged by combining the appearance of the resin.
FIG. 5 is a scanning electron microscope image of the magnetic polydivinylbenzene microsphere resin prepared in example 1 of the present invention. The monomer adopted by the embodiment of the invention only contains divinylbenzene, and the surface of the obtained resin is smooth and the particle size distribution of the resin is narrow as shown under an electron microscope.
The particle size distribution diagrams of the magnetic polydivinylbenzene microsphere resins prepared in examples 1, 2, 1, 2 and 3 of the invention are shown in sequence in (a), (b), (c), (d) and (e) in fig. 6, and as can be seen from fig. 6, the particle size distribution of the resins in examples 1 and 2 is basically 100 μm to 250 μm, the particle size distribution is narrow, the particle size distribution of the resins in comparative examples 1, 2 and 3 is wide, and some of the resins even reach more than 1000 μm, which shows that the resins in the examples have obvious advantages in the aspect of the distribution width of the particle size. The specific dispersant adopted by the invention and the monomer act together, and the dispersant component in the embodiment can enable the monomer to be scattered by the stirring paddle, and then wrap scattered small monomer droplets, so that the small monomer droplets do not form large particles and are not aggregated suddenly in the polymerization process, and the particle size is moderate. The divinylbenzene is used as a monomer, and the divinylbenzene has two suspended double bonds, so that the resin microspheres can be subjected to three-dimensional crosslinking in the forming process, the internal structure of the resin is compact, and the resin is favorable for forming the condition of narrow particle size. The narrow particle size is an important expression of excellent process of the resin microspheres, the physicochemical properties of the resin microspheres with narrow particle size distribution are closer, and the reproducibility of subsequent research is higher.
The magnetic polydivinylbenzene microsphere resins prepared in examples 1-2 and comparative examples 1-3 were measured by a BELSORP type specific surface area and pore analyzer manufactured by BEL of Japan to obtain a nitrogen adsorption-desorption isotherm thereof, and the total adsorption Vm and the specific surface area a were obtained by analyzing the isotherm by the BET methods,BETTotal pore volume (p/p)00.990) and average pore diameter.
TABLE 1 physical parameters of magnetic polydivinylbenzene microsphere resins prepared in examples 1-2 and comparative examples 1-3
Table 1 shows physical parameters measured on the magnetic polydivinylbenzene microsphere resins prepared in examples 1-2 and comparative examples 1-3 of the present invention, wherein Vm is total adsorption amount, as,BETIs the specific surface area.
In fig. 7, (a), (b), (c), (d), and (e) are nitrogen adsorption-desorption curves of the magnetic polydivinylbenzene microsphere resins prepared in example 1, example 2, comparative example 1, comparative example 2, and comparative example 3 of the present invention in this order. As can be seen from FIG. 7, the nitrogen adsorption effect of examples 1 and 2 is significantly higher than that of the comparative example during the nitrogen adsorption-desorption process, which indicates that the resin of the example has a more abundant cell structure and the N of the resin of the example2The change trend of the adsorption capacity can judge that large, medium and small holes exist in the resin, and the characteristic is favorable for the adsorption of the resin to various adsorbates in the embodiment.
Example 3
The magnetic polydivinylbenzene microsphere resin prepared in example 1 was used to adsorb several nitrobenzene compounds, such as 2-nitrotoluene, 2, 4-dinitrotoluene, and 2,4, 6-trinitrotoluene, to determine the adsorption kinetics curve. The concentration of nitrobenzene compounds in the solution after adsorption needs to be determined by using a standard curve.
The determination method utilized in the embodiment is a static adsorption characterization method, the narrow particle size distribution makes the reproducible probability of the experimental results in the adsorption process of different batches higher, and in the adsorption research method not adopted in the invention, namely the research of dynamic adsorption, the narrow particle size distribution has more advantages for filling, so that the packed column is more compact, and the material is more fully utilized.
Determination of the standard curve:
TNT, DNT and o-MNT are dissolved by a small amount of ethanol, and deionized water is added to dilute the solution to 1000mL to prepare 150mg/L TNT solution, 250mg/L DNT solution and 250mg/L o-MNT solution. The solutions are respectively diluted to be prepared into the following series of concentration solutions (namely 0mg/L, 10mg/L, 20mg/L, 30mg/L and 40mg/L), ultraviolet absorbance test is carried out, and a standard curve of absorbance to concentration is drawn.
Determination of adsorption kinetics:
0.06g of the resin prepared in example 1 was taken and placed in 250mL Erlenmeyer flasks, and 180mL of 150mg/L TNT solution, 250mg/L DNT solution or 250mg/L o-MNT solution was added. Oscillating at 298K, 200rpm, sampling at different times, performing ultraviolet absorbance test, finding out the corresponding concentration of the solution through a standard curve, and calculating the adsorption capacity of the resin according to the following formula:
Qt=(c0-ce)·V/W
in the formula, QtThe adsorption capacity (mg/g) of the resin at time t (min), the ce is the concentration (mg/L) of the solution at time t (min), c0Is the initial concentration of the solution (mg/L), V is the volume of the solution (L), and W is the mass of the resin (g).
Fig. 8 is a graph showing the adsorption performance of the magnetic polydivinylbenzene microsphere resin on 2,4, 6-trinitrotoluene, which is obtained by the determination in example 3, and it can be seen from fig. 8 that the magnetic polydivinylbenzene microsphere resin basically reaches the adsorption equilibrium within 240min, and at the initial stage, the adsorption rate rapidly increases with time, and reaches the adsorption equilibrium after gradually slowing down. Because the resin has abundant pore channel structures inside, the resin needs a long time for 2,4, 6-trinitrotoluene with larger molecular volume to reach adsorption balance. According to the effect in the figure, the equilibrium adsorption capacity of the magnetic polydivinylbenzene microsphere resin to the 2,4, 6-trinitrotoluene is about 244mg/g, which shows that the resin microsphere has excellent adsorption performance.
FIG. 9 is a graph showing the adsorption performance of 2, 4-dinitrotoluene by magnetic polydivinylbenzene microsphere resin measured in example 3, and it can be seen from FIG. 9 that the resin reaches the adsorption equilibrium substantially within 140min, and the adsorption rate increases rapidly in the initial stage, increases with time, and reaches the adsorption equilibrium after gradually slowing down. The equilibrium adsorption capacity of the magnetic polydivinylbenzene microsphere resin to the 2, 4-dinitrotoluene is about 329mg/g, which shows that the resin has excellent adsorption performance to the 2, 4-dinitrotoluene.
FIG. 10 is a graph showing the adsorption performance of 2-nitrotoluene by magnetic polydivinylbenzene microsphere resin obtained by the determination in example 3, and it can be seen from FIG. 10 that the resin reaches the adsorption equilibrium basically within 60min, and the adsorption rate increases rapidly in the initial stage, increases with time, and reaches the adsorption equilibrium after gradually slowing down. From fig. 10, it can also be known that, for 2-nitrotoluene with a small molecular volume, the resin microspheres can reach adsorption equilibrium within 60min, wherein 1g of the resin microspheres can adsorb 2-nitrotoluene up to 394mg, and thus the resin has excellent adsorption performance on 2-nitrotoluene.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.