A method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization and its lead ion adsorption application

Abstract

The present invention belongs to the technical field of preparation of environmental functional materials, and discloses a method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent with a magnetic ferroferric oxide on the outer surface and a sulfonic acid functionalized concave interface by an emulsion interfacial polymerization method, and its lead ion adsorption application. The present invention first prepares amino magnetic ferroferric oxide, and then uses emulsion interfacial polymerization to prepare a crescent-shaped base material with a convex surface of carboxyl and a concave interface of polystyrene and polydivinylbenzene, and then prepares a magnetic mesoporous sulfonated crescent-shaped adsorbent by Friedel-crafts alkylation reaction, sulfonation reaction and aminocarboxyl dehydration condensation reaction. The adsorbent prepared by the present invention has uniform morphology and is easy to prepare in large quantities; at the same time, the presence of mesopores greatly improves the ability to adsorb Pb (II); secondly, magnetism is conducive to the separation and regeneration of materials, and maintains the stability of the structure in an acidic environment; finally, the sulfonic acid group has specific adsorption for Pb (II).

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of environmental functional materials, and relates to a method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by an emulsion interfacial polymerization method and its lead ion adsorption application. Background Art

[0002] Janus particles have been applied in many fields because of their special practicality and attractiveness due to their anisotropic shapes or properties. For example, amphiphilic Janus silica particles (JSP) effectively disperse oil pollutants in seawater; Janus nanofibrous porous membranes reported by Xu are used for directional water transport for particulate matter filtration and volatile organic compound adsorption; Janus silica nanosheets prepared by Liu simultaneously adsorb 2,6-dichlorophenol and Pb(II). In particular, when Janus particles are magnetic while being applied, the problems of separation and regeneration are easier to solve. Magnetic Janus particles composed of iron oxide particles and polystyrene have been reported to have potential applications in controlled interfacial catalysis.

[0003] Porous materials with pore sizes in the range of 2-50 nm are called mesoporous materials, such as aerogels, mesoporous silica, mesoporous carbon, etc. It is well known that mesoporous materials have the following excellent properties: (1) adjustable pore size, (2) high specific surface area, (3) modifiable pore inner wall, and (4) good chemical stability and thermal stability. Due to the above excellent properties, they have been applied in many fields such as separation, catalysis, drug delivery and environmental remediation. Among them, mesoporous polymers are mostly used as adsorbent carrier materials, and the adsorption sites are increased by modifying specific functional groups on the inner surface of the pore structure.

[0004] When the sulfonic acid group is not in strong acid conditions, its negative charge can produce electrostatic adsorption with metal ions. In recent years, functional group grafting and sulfonation modification are effective ways to graft sulfonic acid groups onto carriers. Liu used graft copolymerization to prepare cellulose-g-poly-(acrylamide-co-sulfonic acid) polymer biosorbent (CASA) for the adsorption of Cr(III) in leather wastewater. In order to improve the adsorption performance and achieve rapid separation, this work designed a magnetic mesoporous sulfonated polystyrene-polydivinylbenzene crescent-shaped composite material with surface modified sulfonic acid groups. Summary of the invention

[0005] The present invention solves the problems of separation and regeneration difficulties, batch preparation difficulties and poor adsorption selectivity in the prior art, and provides an emulsion interfacial polymerization method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent and its lead ion adsorption application.

[0006] The present invention adds a surfactant sodium dodecyl sulfate to a mixed solution of 1-chlorodecane and water to prepare an oil-in-water emulsion, then adds an aqueous solution containing non-crosslinked polystyrene particles and stirs for a certain period of time, then adds a single emulsion formed by ultrasound of styrene, divinylbenzene, acrylic acid and azobisisobutyronitrile to the above solution and continues to react for a certain period of time, and finally adds an aqueous solution containing PVA to the above reaction solution to form a crescent-shaped base material (PS-DVB / PAA) after emulsion interfacial polymerization. Then, by Friedel-crafts alkylation reaction, the prepared PS-DVB / PAA is reacted with anhydrous aluminum chloride using 1,2-dichloroethane as solvent, and a yellow-brown product is obtained after washing, which is a mesoporous crescent-shaped polymer (MP PS-DVB / PAA) to increase the specific surface area. Secondly, MP PS-DVB / PAA is reacted with concentrated sulfuric acid, and the black material obtained after sulfonation is a sulfonated crescent-shaped polymer (MP SPS-DVB / PAA). Finally, MP SPS-DVB / PAA, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) were added to the aqueous solution, and after activation, the prepared aminoferric oxide (NH2-Fe3O4) was added to react to obtain a magnetic mesoporous sulfonated crescent-shaped polymer adsorbent material (MMP SPS-DVB). The prepared material was used for the selective adsorption and separation of Pb(II) in wastewater solution.

[0007] In order to achieve the above technical purpose, the technical solution adopted by the present invention is:

[0008] The invention firstly provides a preparation method of a magnetic mesoporous sulfonated crescent-shaped adsorbent, and secondly provides a method for adsorbing lead ions in wastewater using the magnetic mesoporous sulfonated crescent-shaped adsorbent.

[0009] The present invention also provides a method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent and its application in adsorbing lead ions, the method comprising the following steps:

[0010] (1) Preparation of aminoferric oxide (NH2-Fe3O4):

[0011] Ferric chloride hexahydrate, ethylene glycol, trisodium citrate and sodium acetate were added to a beaker, and ultrasonic treatment was performed for the first time until the solution was clear. Then, the solution was transferred to a high-pressure reactor and reacted for a period of time. After cooling to room temperature, the solution was washed with ethanol and water three times respectively, and vacuum dried to obtain spherical ferrosoferric oxide.

[0012] Then, ethanol, 3-aminopropyltriethoxysilane, glacial acetic acid and the ferrosoferric oxide prepared above were added to a three-necked flask and uniformly dispersed by ultrasonic for a second time, and then mechanically stirred in a water bath for reaction. The obtained product was washed three times with ethanol and vacuum dried overnight.

[0013] (2) Preparation of crescent-shaped mesoporous polymer (MP PS-DVB / PAA) by emulsion interfacial polymerization:

[0014] (2.1) Styrene, sodium chloride and ammonium persulfate were added to deionized water and ultrasonically dispersed uniformly. The solution was deoxygenated at room temperature and then thermally polymerized. After the product was cooled, it was washed several times with ethanol and water respectively and freeze-dried to obtain polystyrene spheres (PS).

[0015] (2.2) First, sodium dodecyl sulfate, PS balls and deionized water are mixed evenly to obtain dispersion A; sodium dodecyl sulfate, 1-chlorodecane and deionized water are ultrasonically treated for the third time to form an oil-in-water emulsion, which is solution B; then dispersion A and solution B are mixed, heated in a water bath and magnetically stirred for a certain period of time to obtain reaction system C;

[0016] (2.3) Subsequently, divinylbenzene, azobisisobutyronitrile and styrene were used as the mixed oil phase, sodium dodecyl sulfate, deionized water and acrylic acid were used as the mixed water phase, and the two were ultrasonically emulsified to form an oil-in-water emulsion (St / DVB-in-AA), which was then added to the above reaction system C and reacted at a certain temperature for a certain time to obtain a reaction system D. (2.4) Finally, the aqueous solution of PVA was added to the above reaction system D, N2 was introduced at room temperature for deoxygenation, and the reaction was carried out in an oil bath. The product was washed several times with deionized water and ethanol, respectively, to obtain a crescent-shaped polymer (PS-DVB / PAA).

[0017] (2.5) PS-DVB / PAA and 1,2-dichloroethane were added to a three-necked flask and reacted in a water bath. Then, 1,2-dichloroethane containing anhydrous aluminum chloride was added and reacted for a period of time under magnetic stirring. The obtained product was first washed several times with a hydrochloric acid acetone solution and then washed several times with methanol. The product was dried overnight by air blowing to obtain a crescent-shaped mesoporous polymer (MP PS-DVB / PAA).

[0018] (3) Preparation of mesoporous sulfonated crescent polymer (MP SPS-DVB / PAA):

[0019] The crescent-shaped mesoporous polymer MP PS-DVB / PAA and concentrated sulfuric acid were added into a three-necked flask, and reacted under magnetic stirring in an oil bath after ultrasonication. The reaction solution was diluted with a large amount of deionized water and washed to neutrality and then dried by blasting.

[0020] (4) Preparation of magnetic mesoporous sulfonated crescent-shaped polymer (MMP SPS-DVB):

[0021] Mesoporous sulfonated crescent polymer MP SPS-DVB / PAA, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) were added to a beaker containing deionized water, and reacted by magnetic stirring for the first time at room temperature, followed by adding NH2-Fe3O4 for the second magnetic stirring reaction. After washing with water several times, the final product, magnetic mesoporous sulfonated crescent polymer MMP SPS-DVB, was obtained.

[0022] In step (1), the amount ratio of ferric chloride hexahydrate, ethylene glycol, trisodium citrate and sodium acetate is 3.25g:100mL:1.3g:6g, the first ultrasonic time is 1.5-2.0h, the reaction temperature is 195-205°C, and the reaction time is 10h.

[0023] In step (1), the ratio of ethanol, 3-aminopropyltriethoxysilane, glacial acetic acid and ferrosoferric oxide used is 50mL:5mL:10μL:0.5g, the second ultrasonic time is 5-10min, the water bath temperature is 35-45°C, the mechanical stirring is 200-300rpm, the reaction time is 12h, and the vacuum drying temperature is 35-45°C.

[0024] In step (2.1), the ratio of styrene, sodium chloride, ammonium persulfate and deionized water used is 5.8324 g: 100 mg: 68.46 mg: 60 mL, the deoxygenation time is 30 to 60 min, the thermal polymerization reaction temperature is 70° C., and the reaction time is 24 to 24.5 h.

[0025] In step (2.2),

[0026] In dispersion A, the ratio of sodium dodecyl sulfate, PS spheres, and deionized water is 50 mg: 0.2 g to 0.25 g: 20 mL;

[0027] In solution B, the ratio of sodium dodecyl sulfate, 1-chlorodecane and deionized water is 25 mg: 0.1 mL: 9.9 mL, and the third ultrasonication time is 5 to 10 min;

[0028] The volume ratio of dispersion A to solution B is 2:1; the water bath heating temperature is 35-45° C., and the reaction time is 14 h to 20 h.

[0029] In step (2.3),

[0030] In the mixed oil phase, the mixing ratio of divinylbenzene, azobisisobutyronitrile and styrene is 0.9113 g: 0.0394 g: 1.3539 g;

[0031] In the mixed aqueous phase, the ratio of sodium dodecyl sulfate, deionized water, and acrylic acid was 25 mg: 8 mL: 0.504 g;

[0032] Ultrasonic emulsification for 10 to 20 minutes, reaction temperature 35 to 45°C, reaction time 6 hours;

[0033] In the mixed oil phase and the mixed water phase, the dosage ratio of divinylbenzene to sodium dodecyl sulfate is 0.9113 g:25 mg.

[0034] In step (2.4), the volume ratio of the aqueous solution of PVA to the reaction system D is 5:40; in the aqueous solution of PVA, the dosage ratio of PVA to deionized water is 50 mg:5 mL, N2 deoxygenation is performed for 15 to 30 min, the oil bath reaction temperature is 65-75°C, and the reaction time is 13.5 to 14.5 h.

[0035] In step (2.5), the ratio of PS-DVB / PAA, 1,2-dichloroethane and 1,2-dichloroethane containing anhydrous aluminum chloride is 1 g: 14.3 mL: 18 mL, wherein 18 mL of 1,2-dichloroethane contains 1.06 g of anhydrous aluminum chloride. In step (2.5), the reaction temperature in the water bath is 25°C, the reaction time is 12 to 13 hours, and the concentration of the hydrochloric acid in acetone solution is 0.5 M.

[0036] In step (2.5), the magnetic stirring speed is 800-900 rpm, the reaction temperature is 75-85°C, the reaction time is 24-25h, and the air drying temperature is 60°C-70°C.

[0037] In step (3), the ratio of MP PS-DVB / PAA to concentrated sulfuric acid is 1 g:30 mL; the ultrasonic time is 30 to 60 min, the oil bath temperature is 45 to 55° C., the magnetic stirring is 300 to 500 rpm, the reaction time is 7 to 7.5 h, and the air drying temperature is 60 to 70° C.

[0038] In step (4), the ratio of MP SPS-DVB / PAA, EDC, NHS, deionized water and NH2-Fe3O4 used is 100mg~200mg: 25mg~50mg: 12.5mg~25mg: 10mL: 25mg~100mg; the magnetic stirring speed is 800~1000rpm, the first magnetic stirring reaction time is 2~2.5h; the second magnetic stirring reaction time is 11~13h.

[0039] The magnetic mesoporous sulfonated crescent-shaped polymer MMP SPS-DVB prepared by the present invention is used for adsorbing lead ions in wastewater. The specific usage is: placing the magnetic mesoporous sulfonated crescent-shaped polymer MMP SPS-DVB in lead ion wastewater, shaking it to adsorb the lead ions, and detecting the adsorbed solution with an atomic absorption spectrophotometer.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] The present invention uses crescent-shaped microspheres as the base material, and constructs a magnetic mesoporous sulfonated crescent-shaped adsorbent (MMP SPS-DVB) through Friedel-Crafts alkylation reaction, sulfonation reaction and aminocarboxyl dehydration condensation reaction, which has good selectivity and adsorption performance; the mesoporous structure prepared by Friedel-Crafts alkylation reaction greatly increases the Pb 2+ adsorption sites; at the same time, the grafting of magnetic ferroferric oxide magnetic particles (NH2-Fe3O4) makes the adsorbent easy to separate and regenerate. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The SEM images of (a) PS particles and (b) PS-DVB / PAA in Example 1, (c) EDX image of MP SPS-DVB / PAA, and (d) TEM image of PS-DVB / PAA.

[0043] Figure 2 SEM images of (a) Fe3O4 nanoparticles, (b) MP SPS-DVB / PAA and (c) MMP SPS-DVB in Example 1.

[0044] Figure 3 These are the infrared spectra of (a) ferrosoferric oxide before and after amination, and (b) PS-DVB / PAA, MP PS-DVB / PAA, MP SPS-DVB / PAA and MMP SPS-DVB in Example 1.

[0045] Figure 4 XPS spectra of PS-DVB / PAA, MP SPS-DVB / PAA, and MMP SPS-DVB in Example 1 (a), high-resolution spectra of C1s (b), O1s (c), and S2p (d) in MPSPS-DVB / PAA, and high-resolution spectra of N1s (e), C1s (f), O1s (g), and S2p (h) in MMP SPS-DVB.

[0046] Figure 5 ] are the hysteresis loops of NH2-Fe3O4 and MMP SPS-DVB in Example 1.

[0047] Figure 6 The effect of solution pH value in Example 1 on the adsorption performance (a) and Zeta potential (b) of MP PS-DVB / PAA, MP SPS-DVB / PAA and MMP SPS-DVB.

[0048] Figure 7The adsorption kinetics data and fitting model of MP SPS-DVB / PAA and MMP SPS-DVB in Example 1 (a) and the adsorption equilibrium and thermodynamic adsorption data and fitting model of MMP PS-DVB (b).

[0049] Figure 8 Competitive adsorption diagram of MMP PS-DVB in Example 1 in a pairwise ion mixture (a) and a mixed ion solution (b).

[0050] Fig. 9 (a) and SEM image (b) of the adsorption-desorption cycle of MMP PS-DVB in Example 1. DETAILED DESCRIPTION

[0051] In the specific embodiment of the present invention, the recognition performance evaluation is carried out according to the following method: a static adsorption experiment is performed. MP PS-DVB / PAA (5 mg) and MMP PS-DVB (5 mg) are added to 5 mL of 200 mg / L Pb in the pH range of 1-6. 2+ The optimal adsorption pH condition of the adsorbed solution was determined by atomic absorption spectrophotometer; 5 mg MP PS-DVB / PAA and 5 mg MMP PS-DVB adsorbent were added to 5 mL (pH = 6) Pb 2+ In the solution, the adsorption time was controlled to explore the adsorption kinetics, and the adsorption data were fitted using pseudo-first-order and pseudo-second-order kinetics to determine the adsorption equilibrium time. In order to explore the adsorption equilibrium and thermodynamic properties, Pb 2+ The initial concentration was controlled at 200-750 mg / L, and the adsorption temperatures were set to 15°C, 25°C and 35°C, respectively. The adsorption data were fitted with the Langmuir model and the Freundlich model to explore the adsorption mechanism of the MMP PS-DVB adsorbent; finally, the adsorption selectivity, regeneration performance and adsorption mechanism of the MMP PS-DVB were discussed.

[0052] The present invention will be further described below in conjunction with specific implementation examples.

[0053] Embodiment 1:

[0054] (1) Preparation of Aminoferric Oxide (NH2-Fe3O4)

[0055] 3.25 g of ferric chloride hexahydrate, 100 mL of ethylene glycol, 1.3 g of trisodium citrate and 6 g of sodium acetate were added to a 250 mL beaker, and ultrasonicated for 1.5 h until the solution was clarified. Then, the solution was transferred to a 200 mL high-pressure reactor and reacted at 200 ° C for 10 h. After cooling to room temperature, the solution was washed three times with ethanol and water respectively, and vacuum dried at 45 ° C for 12 h to obtain spherical ferrosoferric oxide with a size of about 100 nm.

[0056] 0.5 g of the above-prepared ferrosoferric oxide, 50 mL of ethanol, 5 mL of 3-aminopropyltriethoxysilane and 10 μL of glacial acetic acid were added to a 100 mL three-necked flask, and dispersed evenly by ultrasonication for 5 min, and then mechanically stirred (200 rpm) in a 40°C water bath for 12 h. The product was washed three times with ethanol and vacuum dried at 45°C overnight.

[0057] (2) Preparation of crescent-shaped mesoporous polymer (MP PS-DVB / PAA) by emulsion interfacial polymerization

[0058] 5.8324 g of styrene, 100 mg of sodium chloride and 68.46 mg of ammonium persulfate were added to 60 mL of deionized water and dispersed evenly by ultrasonication. The mixture was deoxygenated with N2 at room temperature for 30 min, and then the solution was polymerized at 70 °C for 24 h. After the product was cooled, it was washed with ethanol and water three times each, and freeze-dried to obtain polystyrene spheres (PS) with a size of 1 μm.

[0059] 25 mg of sodium dodecyl sulfate, 0.1 mL of 1-chlorodecane and 9.9 mL of deionized water were added to a 25 mL beaker and ultrasonicated for 5 min to form an oil-in-water emulsion. The emulsion was then added to a 100 mL three-necked flask containing 50 mg of sodium dodecyl sulfate, 0.2 g of PS balls and 20 mL of deionized water and magnetically stirred in a 40 °C water bath for 20 h.

[0060] Subsequently, a mixture of 0.9113 g of divinylbenzene, 0.0394 g of azobisisobutyronitrile and 1.3539 g of styrene oil phase was added to an aqueous phase consisting of 25 mg of sodium dodecyl sulfate, 8 mL of deionized water and 0.504 g of acrylic acid, and after ultrasonic emulsification for 10 min to form an oil-in-water emulsion (St / DVB-in-AA), it was added to the above reaction system and reacted at 40°C for 6 h.

[0061] Finally, 5 mL of an aqueous solution containing 50 mg of PVA was added to the above solution, N2 was introduced for deoxygenation at room temperature for 15 min, and the reaction was carried out at 70°C for 14 h. The product was washed three times with deionized water and ethanol respectively to obtain a 2-3 μm crescent-shaped polymer (PS-DVB / PAA).

[0062] 1 g PS-DVB / PAA and 14.3 mL 1,2-dichloroethane were added to a 100 mL three-necked flask and reacted in a water bath at 25°C for 12 h. Then, 18 mL 1,2-dichloroethane containing 1.06 g anhydrous aluminum chloride was added and reacted at 80°C for 24 h under 800 rpm magnetic stirring. The obtained product was first washed 3 times with 0.5 M hydrochloric acid in acetone solution and then washed 3 times with methanol. It was dried overnight at 60°C to obtain a crescent-shaped mesoporous polymer (MP PS-DVB / PAA).

[0063] (3) Preparation of mesoporous sulfonated crescent-shaped polymer (MP SPS-DVB / PAA)

[0064] 1 g MP PS-DVB / PAA and 30 mL concentrated sulfuric acid were added to a 100 mL three-necked flask. After ultrasonic treatment for 30 min, the mixture was reacted for 7 h in a 50 °C oil bath with magnetic stirring at 330 rpm. The reaction solution was diluted with a large amount of deionized water, washed to neutrality, and dried at 60 °C with air.

[0065] (4) Preparation of magnetic mesoporous sulfonated crescent-shaped polymer (MMP SPS-DVB)

[0066] 100 mg MP SPS-DVB / PAA, 25 mg EDC and 12.5 mg NHS were added into a 25 mL beaker containing 10 mL deionized water, and reacted with magnetic stirring at 1000 rpm at room temperature for 2 h. Subsequently, 25 mg NH2-Fe3O4 was added and magnetic stirring was performed for 12 h. The final product was obtained after washing with water three times.

[0067] (5) Selective adsorption of lead ions in wastewater by MMP SPS-DVB

[0068] The magnetic mesoporous sulfonated crescent polymer (MMP SPS-DVB) was placed in lead ion wastewater to adsorb the lead ions, and the adsorbed solution was detected using an atomic absorption spectrophotometer.

[0069] Embodiment 2:

[0070] (1) Preparation of Aminoferric Oxide (NH2-Fe3O4)

[0071] 3.25 g of ferric chloride hexahydrate, 100 mL of ethylene glycol, 1.3 g of trisodium citrate and 6 g of sodium acetate were added to a 250 mL beaker, and ultrasonicated for 1.5 h until the solution was clarified. Then, the solution was transferred to a 200 mL high-pressure reactor and reacted at 200 ° C for 10 h. After cooling to room temperature, the solution was washed three times with ethanol and water respectively, and vacuum dried at 45 ° C for 12 h to obtain spherical ferrosoferric oxide with a size of about 100 nm.

[0072] 0.5 g of the above-prepared ferrosoferric oxide, 50 mL of ethanol, 5 mL of 3-aminopropyltriethoxysilane and 10 μL of glacial acetic acid were added to a 100 mL three-necked flask, and dispersed evenly by ultrasonication for 5 min, and then mechanically stirred (200 rpm) in a 40°C water bath for 12 h. The product was washed three times with ethanol and vacuum dried at 45°C overnight.

[0073] (2) Preparation of crescent-shaped mesoporous polymer (MP PS-DVB / PAA) by emulsion interfacial polymerization

[0074] 5.8324 g of styrene, 100 mg of sodium chloride and 68.46 mg of ammonium persulfate were added to 60 mL of deionized water and dispersed evenly by ultrasonication. The mixture was deoxygenated with N2 at room temperature for 30 min, and then the solution was polymerized at 70 °C for 24 h. After the product was cooled, it was washed with ethanol and water three times each, and freeze-dried to obtain polystyrene spheres (PS) with a size of 1 μm.

[0075] 25 mg of sodium dodecyl sulfate, 0.1 mL of 1-chlorodecane and 9.9 mL of deionized water were added to a 25 mL beaker and ultrasonicated for 5 min to form an oil-in-water emulsion. The emulsion was then added to a 100 mL three-necked flask containing 50 mg of sodium dodecyl sulfate, 0.25 g of PS balls and 20 mL of deionized water and magnetically stirred in a 40 °C water bath for 20 h.

[0076] Subsequently, a mixture of 0.9113 g of divinylbenzene, 0.0394 g of azobisisobutyronitrile and 1.3539 g of styrene oil phase was added to an aqueous phase consisting of 25 mg of sodium dodecyl sulfate, 8 mL of deionized water and 0.504 g of acrylic acid, and after ultrasonic emulsification for 10 min to form an oil-in-water emulsion (St / DVB-in-AA), it was added to the above reaction system and reacted at 40°C for 6 h.

[0077] Finally, 50 mg of PVA aqueous solution (5 mL) was added to the above solution, N2 was introduced for deoxygenation at room temperature for 15 min, and the reaction was carried out at 70°C for 14 h. The product was washed three times with deionized water and ethanol respectively to obtain a 2-3 μm crescent-shaped polymer (PS-DVB / PAA).

[0078] 1 g PS-DVB / PAA and 14.3 mL 1,2-dichloroethane were added to a 100 mL three-necked flask and reacted in a water bath at 25°C for 12 h. Then, 18 mL 1,2-dichloroethane containing 1.06 g anhydrous aluminum chloride was added and reacted at 80°C for 24 h under 800 rpm magnetic stirring. The obtained product was first washed 3 times with 0.5 M hydrochloric acid in acetone solution and then washed 3 times with methanol. It was dried overnight at 60°C to obtain a crescent-shaped mesoporous polymer (MP PS-DVB / PAA).

[0079] (3) Preparation of mesoporous sulfonated crescent-shaped polymer (MP SPS-DVB / PAA)

[0080] 1 g MP PS-DVB / PAA and 30 mL concentrated sulfuric acid were added to a 100 mL three-necked flask. After ultrasonic treatment for 30 min, the mixture was reacted for 7 h in a 50 °C oil bath with magnetic stirring at 330 rpm. The reaction solution was diluted with a large amount of deionized water, washed to neutrality, and dried at 60 °C with air.

[0081] (4) Preparation of magnetic mesoporous sulfonated crescent-shaped polymer (MMP SPS-DVB)

[0082] 200 mg MP SPS-DVB / PAA, 50 mg EDC and 25 mg NHS were added into a 25 mL beaker containing 10 mL deionized water, and reacted with magnetic stirring at 1000 rpm at room temperature for 2 h. Subsequently, 100 mg NH2-Fe3O4 was added and magnetic stirring was performed for 12 h. The final product was obtained after washing with water three times.

[0083] (5) Selective adsorption of lead ions in wastewater by MMP SPS-DVB

[0084] The magnetic mesoporous sulfonated crescent polymer (MMP SPS-DVB) was placed in lead ion wastewater to adsorb the lead ions, and the adsorbed solution was detected using an atomic absorption spectrophotometer.

[0085] Embodiment 3:

[0086] (1) Preparation of Aminoferric Oxide (NH2-Fe3O4)

[0087] 3.25 g of ferric chloride hexahydrate, 100 mL of ethylene glycol, 1.3 g of trisodium citrate and 6 g of sodium acetate were added to a 250 mL beaker, and ultrasonicated for 1.5 h until the solution was clarified. Then, the solution was transferred to a 200 mL high-pressure reactor and reacted at 200 ° C for 10 h. After cooling to room temperature, the solution was washed three times with ethanol and water respectively, and vacuum dried at 45 ° C for 12 h to obtain spherical ferrosoferric oxide with a size of about 100 nm.

[0088] 0.5 g of the above-prepared ferrosoferric oxide, 50 mL of ethanol, 5 mL of 3-aminopropyltriethoxysilane and 10 μL of glacial acetic acid were added to a 100 mL three-necked flask, and dispersed evenly by ultrasonication for 5 min, and then mechanically stirred (200 rpm) in a 40°C water bath for 12 h. The product was washed three times with ethanol and vacuum dried at 45°C overnight.

[0089] (2) Preparation of crescent-shaped mesoporous polymer (MP PS-DVB / PAA) by emulsion interfacial polymerization

[0090] 5.8324 g of styrene, 100 mg of sodium chloride and 68.46 mg of ammonium persulfate were added to 60 mL of deionized water and dispersed evenly by ultrasonication. The mixture was deoxygenated with N2 at room temperature for 30 min, and then the solution was polymerized at 70 °C for 24 h. After the product was cooled, it was washed with ethanol and water three times each, and freeze-dried to obtain polystyrene spheres (PS) with a size of 1 μm.

[0091] 25 mg of sodium dodecyl sulfate, 0.1 mL of 1-chlorodecane and 9.9 mL of deionized water were added to a 25 mL beaker and ultrasonicated for 5 min to form an oil-in-water emulsion. The emulsion was then added to a 100 mL three-necked flask containing 50 mg of sodium dodecyl sulfate, 0.2 g of PS balls and 20 mL of deionized water and magnetically stirred in a 40 °C water bath for 20 h.

[0092] Subsequently, a mixture of 0.9113 g of divinylbenzene, 0.0394 g of azobisisobutyronitrile and 1.3539 g of styrene oil phase was added to an aqueous phase consisting of 25 mg of sodium dodecyl sulfate, 8 mL of deionized water and 0.504 g of acrylic acid, and after ultrasonic emulsification for 10 min to form an oil-in-water emulsion (St / DVB-in-AA), it was added to the above reaction system and reacted at 40°C for 6 h.

[0093] Finally, 50 mg of PVA aqueous solution (5 mL) was added to the above solution, N2 was introduced for deoxygenation at room temperature for 15 min, and the reaction was carried out at 70°C for 14 h. The product was washed three times with deionized water and ethanol respectively to obtain a 2-3 μm crescent-shaped polymer (PS-DVB / PAA).

[0094] 1 g PS-DVB / PAA and 14.3 mL 1,2-dichloroethane were added to a 100 mL three-necked flask and reacted in a water bath at 25°C for 12 h. Then, 18 mL 1,2-dichloroethane containing 1.06 g anhydrous aluminum chloride was added and reacted at 80°C for 24 h under 800 rpm magnetic stirring. The obtained product was first washed 3 times with 0.5 M hydrochloric acid in acetone solution and then washed 3 times with methanol. It was dried overnight at 60°C to obtain a crescent-shaped mesoporous polymer (MP PS-DVB / PAA).

[0095] (3) Preparation of mesoporous sulfonated crescent-shaped polymer (MP SPS-DVB / PAA)

[0096] 1 g MP PS-DVB / PAA and 30 mL concentrated sulfuric acid were added to a 100 mL three-necked flask. After ultrasonic treatment for 30 min, the mixture was reacted for 7 h in a 50 °C oil bath with magnetic stirring at 330 rpm. The reaction solution was diluted with a large amount of deionized water, washed to neutrality, and dried at 60 °C with air.

[0097] (4) Preparation of magnetic mesoporous sulfonated crescent-shaped polymer (MMP SPS-DVB)

[0098] 200 mg MP SPS-DVB / PAA, 50 mg EDC and 25 mg NHS were added into a 25 mL beaker containing 10 mL deionized water, and reacted with magnetic stirring at 1000 rpm at room temperature for 2 h. Subsequently, 100 mg NH2-Fe3O4 was added and magnetic stirring was performed for 12 h. The final product was obtained after washing with water three times.

[0099] (5) Selective adsorption of lead ions in wastewater by MMP SPS-DVB

[0100] The experimental steps are the same as in Example 2.

[0101] Figure 1 (b) proves that the crescent-shaped structure was successfully synthesized. (c) EDX analysis of PS-DVB / PAA shows the presence of O element in the material, indicating that acrylic acid is polymerized on the material. Figure 1 (d) is the TEM image of PS-DVB / PAA, demonstrating that the outer surface is an acrylic polymer layer.

[0102] Figure 2 (a) shows Fe3O4 nanoparticles with a size of about 100 nm. (b) After the Friedel-Crafts alkylation and sulfonation reaction of MP SPS-DVB / PAA, the morphology of the material did not change. (c) The SEM image of MMP SPS-DVB shows that aminoferric tetroxide successfully reacted with carboxyl groups and grafted onto the outer surface of the material.

[0103] Figure 3 (a) 595.35cm -1 The characteristic absorption peak at 879.34 cm is the vibration of Fe-O bond. -1 and 1087cm -1 A new characteristic peak appears at (b), which belongs to the characteristic absorption peak of Si-O-Si, proving that the modification of amino silane coupling agent is successful. -1 The appearance of -CH2 stretching vibration at 1162.51 cm -1 and 1034.47cm -1 The characteristic peaks of -SO3H and 624.07cm -1 The broad peak nearby is the characteristic peak of Fe-O bond, indicating the successful grafting of sulfonic acid group and ferrosoferric oxide.

[0104] Figure 4 The full XPS spectrum in the figure shows the presence of C1s and O1s in all samples. In addition, the new signal peaks at 168.11eV, 400.36eV ​​and 711.16eV correspond to S2p, N1s and Fe4f, respectively, proving that the S element and amino-ferrous oxide have been successfully modified.

[0105] Figure 5 The saturation magnetization value of MMP SPS-DVB is 10.48emu g -1 , the external magnetic field can still quickly separate MMP SPS-DVB from the solution.

[0106] Test Example 1:

[0107] Solution pH is an important factor affecting ion adsorption. Figure 6 As shown, PS-DVB / PAA has a significant effect on Pb 2+ There is basically no adsorption effect. MP SPS-DVB / PAA and MMP SPS-DVB have no adsorption effect on Pb 2+ The adsorption capacity increases with the increase of pH, and the adsorption effect is best at pH=6.

[0108] Test Example 2:

[0109] The water bath oscillation time of MP SPS-DVB / PAA and MMP SPS-DVB adsorbents and lead ion solution was controlled to be 3min, 8min, 13min, 23min, 33min, 60min and 120min respectively. Figure 7 In (a), both MP SPS-DVB / PAA and MMP SPS-DVB reached kinetic adsorption equilibrium at 33 min. The pseudo-second-order kinetic model is more consistent with the actual kinetic adsorption process, which also indicates that Pb 2+ The adsorption process between the adsorbent and the adsorbent is mainly dominated by chemical reactions. Figure 7 (b) The increase in temperature is conducive to the increase in lead ion adsorption capacity. 2+ The electrostatic interaction and coordination interaction between them are the main adsorption mechanisms, while multi-molecular layer adsorption is a secondary process.

[0110] Test Example 3:

[0111] Experimental selection Cd 2+ 、Co 2+ , Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ As a competitive ion to study the effect of MMP PS-DVB on Pb 2+ selectivity. Figure 8 Medium Pb 2+ K d The value is close to 204.37, which is much higher than other competing ions, proving that MMP PS-DVB has a strong affinity for Pb 2 + Has strong affinity. In addition, Fig. 9 (a) After three adsorption-desorption cycles, the desorption efficiency of MMP PS-DVB remained above 90%, and Fig. 9 (b) After several acid washes, the MMP PS-DVB has good reusability and stability.

[0112] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization, characterized in that: The steps include: (1) Prepare aminoferric oxide NH2-Fe3O4 for standby use: (2) Preparation of crescent-shaped mesoporous polymer MP PS-DVB / PAA by emulsion interfacial polymerization: (2.1) Styrene, sodium chloride and ammonium persulfate are added to deionized water and ultrasonically dispersed uniformly, and deoxygenated at room temperature. The solution is then heated for polymerization. After the product is cooled, it is washed several times with ethanol and water, and freeze-dried to obtain polystyrene spheres PS; (2.2) First, sodium dodecyl sulfate, PS balls and deionized water are mixed evenly to obtain dispersion A; sodium dodecyl sulfate, 1-chlorodecane and deionized water are ultrasonically formed into an oil-in-water emulsion to obtain solution B; then dispersion A and solution B are mixed, heated in a water bath and magnetically stirred for a certain period of time to obtain reaction system C; (2.3) Subsequently, divinylbenzene, azobisisobutyronitrile and styrene were used as a mixed oil phase, sodium dodecyl sulfate, deionized water and acrylic acid were used as a mixed water phase, and the two were ultrasonically emulsified to form an oil-in-water emulsion St / DVB-in-AA, which was then added to the above reaction system C and reacted at 35-45°C for 6 hours to obtain a reaction system D; (2.4) Finally, an aqueous solution of PVA was added to the above reaction system D, N2 was introduced at room temperature for deoxygenation, and the reaction was carried out in an oil bath. The product was washed several times with deionized water and ethanol, respectively, to obtain a crescent-shaped polymer PS-DVB / PAA; (2.5) PS-DVB / PAA and 1,2-dichloroethane were added to a three-necked flask, reacted in a water bath, and then 1,2-dichloroethane containing anhydrous aluminum chloride was added. The reaction was carried out under magnetic stirring for 12 to 13 hours. The obtained product was first washed several times with a hydrochloric acid acetone solution, and then washed several times with methanol, and dried overnight by forced air to obtain a crescent-shaped mesoporous polymer MP PS-DVB / PAA; (3) Preparation of mesoporous sulfonated crescent-shaped polymer MP SPS-DVB / PAA: Add crescent-shaped mesoporous polymer MP PS-DVB / PAA and concentrated sulfuric acid into a three-necked flask, react under magnetic stirring in an oil bath after ultrasonication, and dilute the reaction solution with a large amount of deionized water and wash it to neutrality and then blow dry it; The ratio of MP PS-DVB / PAA to concentrated sulfuric acid is 1 g:30 mL; the ultrasonic time is 30 to 60 min, the oil bath temperature is 45 to 55° C., the magnetic stirring is 300 to 500 rpm, the reaction time is 7 to 7.5 h, and the blast drying temperature is 60 to 70° C.; (4) Preparation of magnetic mesoporous sulfonated crescent-shaped polymer MMP SPS-DVB: The mesoporous sulfonated crescent polymer MP SPS-DVB / PAA, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide EDC and N-hydroxysuccinimide NHS were added into a beaker containing deionized water, and the reaction was carried out by magnetic stirring for the first time at room temperature, and then NH2-Fe3O4 was added for the second time to carry out magnetic stirring reaction, and the final product, the magnetic mesoporous sulfonated crescent polymer MMPSPS-DVB, was obtained after washing with water for several times; The ratio of MP SPS-DVB / PAA, EDC, NHS, deionized water and NH2-Fe3O4 used is 100mg~200mg: 25mg~50mg: 12.5mg~25mg: 10mL: 25mg~100mg; the magnetic stirring speed is 800~1000rpm, the first magnetic stirring reaction time is 2~2.5h; the second magnetic stirring reaction time is 11~13h.

2. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (1), the preparation steps of aminoferric oxide are: Add ferric chloride hexahydrate, ethylene glycol, trisodium citrate and sodium acetate into a beaker, perform ultrasonic treatment for the first time until the solution is clear, then transfer to a high-pressure reactor to react for a period of time, cool to room temperature, wash with ethanol and water three times respectively, and vacuum dry to obtain spherical ferrosoferric oxide; Then, ethanol, 3-aminopropyltriethoxysilane, glacial acetic acid and the ferrosoferric oxide prepared above were added to a three-necked flask and uniformly dispersed by ultrasonic for a second time, and then mechanically stirred in a water bath for reaction. The obtained product was washed three times with ethanol and vacuum dried overnight. in, The amount ratio of ferric chloride hexahydrate, ethylene glycol, trisodium citrate and sodium acetate used is 3.25g:100mL:1.3g:6g, the first ultrasonic time is 1.5-2.0h, the reaction temperature is 195-205℃, and the reaction time is 10h; The ratio of ethanol, 3-aminopropyltriethoxysilane, glacial acetic acid and ferrosoferric oxide used is 50mL:5mL:10μL:0.5g, the second ultrasonic time is 5-10min, the water bath temperature is 35-45°C, the mechanical stirring is 200-300rpm, the reaction time is 12h, and the vacuum drying temperature is 35-45°C.

3. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (2.1), the ratio of styrene, sodium chloride, ammonium persulfate and deionized water used is 5.8324 g: 100 mg: 68.46 mg: 60 mL, the deoxygenation time is 30 to 60 min, the thermal polymerization reaction temperature is 70° C., and the reaction time is 24 to 24.5 h.

4. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (2.2), In dispersion A, the ratio of sodium dodecyl sulfate, PS spheres, and deionized water is 50 mg: 0.2 g to 0.25 g: 20 mL; In solution B, the ratio of sodium dodecyl sulfate, 1-chlorodecane and deionized water is 25 mg: 0.1mL: 9.9mL, ultrasonic time 5-10min; The volume ratio of dispersion A to solution B is 2:1; the water bath heating temperature is 35-45° C., and the reaction time is 14 h to 20 h.

5. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (2.3), In the mixed oil phase, the mixing ratio of divinylbenzene, azobisisobutyronitrile and styrene is 0.9113 g: 0.0394 g: 1.3539 g; In the mixed aqueous phase, the ratio of sodium dodecyl sulfate, deionized water, and acrylic acid was 25 mg: 8 mL: 0.504 g; Ultrasound emulsification 10-20 minutes; In the mixed oil phase and the mixed water phase, the dosage ratio of divinylbenzene to sodium dodecyl sulfate is 0.9113 g:25 mg.

6. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (2.4), the volume ratio of the aqueous solution of PVA to the reaction system D is 5:40; in the aqueous solution of PVA, the dosage ratio of PVA to deionized water is 50 mg:5 mL, N2 deoxygenation is performed for 15 to 30 min, the oil bath reaction temperature is 65-75°C, and the reaction time is 13.5 to 14.5 h.

7. The method for preparing a magnetic mesoporous sulfonated crescent-shaped adsorbent by emulsion interfacial polymerization as claimed in claim 1, characterized in that: In step (2.5), the ratio of PS-DVB / PAA, 1,2-dichloroethane and 1,2-dichloroethane containing anhydrous aluminum chloride is 1 g: 14.3 mL: 18 mL, wherein 18 mL of 1,2-dichloroethane contains 1.06 g of anhydrous aluminum chloride; the reaction temperature in the water bath is 25°C, and the concentration of the hydrochloric acid in acetone solution is 0.5 M; The magnetic stirring speed is 800-900 rpm. Under the magnetic stirring condition, the reaction temperature is 75-85°C, the reaction time is 24-25h, and the blast drying temperature is 60°C-70°C.

8. Use of the magnetic mesoporous sulfonated crescent-shaped adsorbent prepared by the method according to any one of claims 1 to 7 for adsorbing lead ions in wastewater.

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