Magnetic ion imprinted polymer as well as preparation method and application thereof

Abstract

The invention discloses a magnetic ion imprinted polymer as well as a preparation method and application thereof. The preparation method of the magnetic ion imprinted polymer comprises the following steps: 1) dispersing a functional monomer and template molecules in a solvent for pre-assembly to obtain a complex solution; 2) dispersing the oleic acid-coated modified Fe3O4 particles, a cross-linking agent and an initiator by using a solvent, and then adding into the complex solution for polymerization reaction to obtain a magnetic polymer; and 3) washing the magnetic polymer with an eluent to obtain the magnetic ion imprinted polymer. The magnetic ion imprinted polymer can specifically recognize and adsorb Sb oxygen-containing anions, is easy to separate from wastewater, is easy to regenerate, can be used for efficiently recovering and recycling antimony in antimony-containing wastewater, and is simple in preparation method, easy in raw material obtaining, low in production cost and suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a magnetic ion-imprinted polymer, its preparation method, and its application. Background Technology

[0002] Antimony (Sb) is an important metallic element that plays an irreplaceable role in high-temperature alloy preparation, semiconductor electronic component packaging, energy storage battery electrode materials, and the synthesis of polymer flame retardants. However, with the increasing scale of antimony mining and smelting, water pollution caused by antimony-containing wastewater has become increasingly serious, resulting in a significant waste of resources. Therefore, how to efficiently recover and reuse antimony-containing wastewater has become an urgent problem to be solved.

[0003] Ion-imprinted polymers (IIPs) are highly selective separation materials capable of specifically recognizing and adsorbing target ions, and hold promise for treating antimony-containing wastewater. However, existing IIPs primarily target organic pollutants (e.g., dyes, pesticide residues) or cationic heavy metals (e.g., copper, lead, cadmium), lacking IIPs capable of specifically recognizing and adsorbing anionic heavy metal ions (especially antimony ions, which often exist as Sb(III) / Sb(V) oxyanions and are easily affected by other anions in the water). Therefore, the treatment of heavy metal-polluted wastewater containing anionic heavy metal ions remains a significant challenge.

[0004] Therefore, it is of great significance to develop an ion-imprinted polymer that can specifically recognize and adsorb Sb oxygen-containing anions, is easy to separate from wastewater, is easy to regenerate, and has low production costs. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic ion-imprinted polymer, its preparation method, and its application.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing a magnetic ion-imprinted polymer includes the following steps: 1) The functional monomer and template molecule are dispersed in a solvent for pre-assembly. The functional monomer is at least one of 4-vinylpyridine, hydroxyethyl methacrylate, and methacrylic acid, and the template molecule is at least one of potassium antimony tartrate and potassium antimony pyroantimonate, to obtain a complex solution. 2) Oleic acid-coated modified Fe3O4 particles, crosslinking agent and initiator were dispersed in a solvent and then added to the complex solution for polymerization to obtain a magnetic polymer; 3) The magnetic polymer was washed with an eluent to obtain a magnetic ion-imprinted polymer.

[0008] Preferably, the ratio of the functional monomer, template molecule, oleic acid-coated modified Fe3O4 particles, and crosslinking agent is 1 mmol: 0.2 mmol to 0.3 mmol: 0.4 g to 0.6 g: 1.8 mmol to 2.2 mmol.

[0009] Preferably, the ratio of the functional monomer to the initiator is 1 mmol: 80 mg to 120 mg.

[0010] Preferably, the template molecule in step 1) is potassium antimony tartrate.

[0011] Preferably, the solvent in step 1) is dimethyl sulfoxide.

[0012] Preferably, the pre-assembly in step 1) is carried out at a temperature of 30℃ to 70℃, and the pre-assembly time is 0.5h to 2h.

[0013] More preferably, the pre-assembly in step 1) is carried out at a temperature of 50℃~60℃ for a time of 0.5h~1.5h.

[0014] Preferably, the pre-assembly in step 1) is carried out in a protective atmosphere.

[0015] Preferably, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0016] Preferably, the particle size of the oleic acid-coated modified Fe3O4 particles in step 2) is <75μm.

[0017] Preferably, the oleic acid-coated modified Fe3O4 particles in step 2) are prepared by a method including the following steps: dispersing Fe3O4 particles in oleic acid, washing with ethanol, and then drying.

[0018] Preferably, the ratio of Fe3O4 particles to oleic acid is 1g:5mL to 10mL.

[0019] Preferably, the crosslinking agent in step 2) is ethylene glycol dimethacrylate (EGDMA).

[0020] Preferably, the initiator in step 2) is azobisisobutyronitrile (AIBN).

[0021] Preferably, the solvent in step 2) is methanol.

[0022] Preferably, the polymerization reaction in step 2) is carried out at a temperature of 50℃ to 80℃ for a reaction time of 15h to 30h.

[0023] More preferably, the polymerization reaction in step 2) is carried out at a temperature of 60℃~70℃ for a reaction time of 20h~24h.

[0024] Preferably, the polymerization reaction in step 2) is carried out in a protective atmosphere.

[0025] Preferably, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0026] Preferably, the eluent in step 3) is a hydrochloric acid solution.

[0027] Preferably, the concentration of the hydrochloric acid solution is 0.1 mol / L to 0.2 mol / L.

[0028] Preferably, the number of times the washing is performed in step 3) is 3 to 5.

[0029] A magnetic ion-imprinted polymer, which is prepared by the above-described method.

[0030] Application of a magnetic ion-imprinted polymer as described above in the treatment of antimony-containing wastewater.

[0031] The beneficial effects of this invention are: the magnetic ion-imprinted polymer of this invention can specifically recognize and adsorb Sb oxygen-containing anions, it is easy to separate from wastewater and easy to regenerate, and can be used for the efficient recovery and recycling of antimony in antimony-containing wastewater. Moreover, its preparation method is simple, the raw materials are readily available, and the production cost is low, making it suitable for large-scale industrial production and application.

[0032] Specifically: 1) This invention introduces specific template molecules through ion imprinting technology, enabling magnetic ion-imprinted polymers to have precise selectivity for target ions, and to achieve efficient identification and separation of Sb oxygen-containing anions in complex samples; 2) The magnetic ion-imprinted polymer of the present invention has high selective adsorption capacity, small particle size, strong adsorption capacity, and high adsorption efficiency. 3) The magnetic ion-imprinted polymer of the present invention has good magnetic response performance, and can be rapidly separated and recovered by an external magnetic field, which improves the ease of operation and practicality; 4) The magnetic ion-imprinted polymer of the present invention contains oleic acid-coated modified Fe3O4 particles. Oleic acid forms a dense hydrophobic coating layer on the surface of the Fe3O4 particles, which not only effectively prevents the aggregation of Fe3O4 particles, allowing the Fe3O4 particles to be uniformly dispersed in the reaction system during the polymerization reaction, but also effectively blocks H2O. +The penetration allows Fe3O4 particles to remain stable in an acidic environment. In addition, the coating layer formed by oleic acid can play a protective role in the repeated adsorption-desorption process, preventing the polymer shell from peeling off or the magnetic core from being oxidized. Thus, the magnetic ion-imprinted polymer can still maintain good performance after multiple adsorption-desorption cycles. 5) The preparation method of the magnetic ion-imprinted polymer of the present invention is simple, the raw materials are readily available, and the production cost is low, making it suitable for large-scale industrial production and application. Attached Figure Description

[0033] Figure 1 The images show SEM images of the magnetic ion-imprinted polymers in Example 1 and the comparative example before and after Sb adsorption.

[0034] Figure 2 The kinetic adsorption curves are for the magnetic ion-imprinted polymers of Examples 1-3 and the comparative examples.

[0035] Figure 3 The graph shows the final removal rate test results of Sb(III) by the magnetic ion-imprinted polymers in Examples 1-3 and the comparative examples.

[0036] Figure 4 The magnetic ion-imprinted polymers of Examples 1-3 are based on cationic Mn 2+ Cu 2+ Fe 2+ and Zn 2+ The figure shows the results of specific adsorption tests under interference.

[0037] Figure 5 The magnetic ion-imprinted polymers of Examples 1-3 are based on anionic AsO3. 3- The specific adsorption test results under interference are shown in the figure.

[0038] Figure 6 The magnetic ion-imprinted polymers of Examples 1-3 are based on anionic PO4. 3- The figure shows the results of specific adsorption tests under interference.

[0039] Figure 7 The graph shows the reusability test results of the magnetic ion-imprinted polymer in Example 1.

[0040] Figure 8 The graph shows the test results of the removal rate of Sb by the magnetic ion-imprinted polymer in actual wastewater in Example 1. Detailed Implementation

[0041] The present invention will be further explained and described below with reference to specific embodiments.

[0042] Example 1: A magnetic ion-imprinted polymer is prepared by the following method: 1) Dissolve 1 mmol of hydroxyethyl methacrylate and 0.25 mmol of potassium antimony tartrate in 25 mL of dimethyl sulfoxide, and then stir at 60 °C for 1 h under a nitrogen atmosphere to obtain a complex solution. 2) 0.5 g of oleic acid-coated modified Fe3O4 particles, 2 mmol of ethylene glycol dimethacrylate and 100 mg of azobisisobutyronitrile were added to 25 mL of methanol and ultrasonically dispersed for 5 min. Then the mixture was added to the complex solution and stirred at 70 °C for 24 h under a nitrogen atmosphere. After filtration, the solid was washed repeatedly with methanol and deionized water to obtain the magnetic polymer. 3) The magnetic polymer was washed four times with a 0.1 mol / L hydrochloric acid solution, then washed with deionized water until the washing solution was neutral, and then freeze-dried to obtain the magnetic ion-imprinted polymer (denoted as 2-IIP).

[0043] Note: The preparation method of oleic acid coated modified Fe3O4 particles is as follows: Fe3O4 particles are stirred and dispersed in oleic acid, with a Fe3O4 particle to oleic acid ratio of 1g:5mL. The particles are then washed with ethanol, air-dried naturally, and passed through a 200-mesh sieve to obtain oleic acid coated modified Fe3O4 particles (particle size <75μm).

[0044] Example 2: A magnetic ion-imprinted polymer (denoted as 4-IIP) is identical to that in Example 1, except that the hydroxyethyl methacrylate in step 1) is replaced with an equimolar amount of 4-vinylpyridine during preparation.

[0045] Example 3: A magnetic ion-imprinted polymer (denoted as M-IIP) is identical to that in Example 1, except that the hydroxyethyl methacrylate in step 1) is replaced with an equimolar amount of methacrylic acid during preparation.

[0046] Comparative example: A magnetic ion-imprinted polymer (denoted as 2-NIP) is identical to that in Example 1 except that potassium antimony tartrate was not added in step 1) of its preparation.

[0047] Performance testing: 1) 4 mg of the magnetic ion-imprinted polymers (2-IIP and 2-NIP) from Example 1 and the comparative example were added to 40 mL of simulated heavy metal wastewater (pH 5) with a Sb(III) concentration of 1 ppm. The mixture was then placed on a shaker at 25°C and 150 rpm for adsorption. After 120 min, the magnetic ion-imprinted polymers were separated and observed using a scanning electron microscope (SEM). The SEM images of the magnetic ion-imprinted polymers before and after Sb adsorption are shown below. Figure 1 (a is the SEM image of 2-IIP before Sb adsorption, b is the SEM image of 2-IIP after Sb adsorption, c is the SEM image of 2-NIP before Sb adsorption, and d is the SEM image of 2-NIP after Sb adsorption.)

[0048] Depend on Figure 1 It can be known that: a) Both 2-IIP and 2-NIP have a microstructure of agglomerated irregular small spheres attached to the surface of Fe3O4 particles. The reason is that the molecularly imprinted materials undergo a polymerization reaction on the surface of Fe3O4 particles. b) The surface of 2-IIP is uneven and the size is 1μm to 10μm. Compared with 2-NIP, it can provide a larger adsorption area, which is beneficial to the adsorption and removal of pollutants.

[0049] 2) 4 mg of the magnetic ion-imprinted polymers (2-IIP, 4-IIP, M-IIP, and 2-NIP) from Examples 1-3 and the comparative examples were added to 40 mL of simulated heavy metal wastewater (pH 5) with a Sb(III) concentration of 1 ppm. The mixture was then placed on a shaker at 25°C and 150 rpm for adsorption experiments. Supernatants were collected at different reaction times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 120 min, and 240 min) and filtered through a 0.22 μm polyethersulfone filter. The Sb(III) concentration was then determined using flame atomic absorption spectrometry. The adsorption capacity was calculated according to Formula 1, and the kinetics were fitted using a Lagrange pseudo-first-order kinetic model (Formula 2) and a Lagrange pseudo-second-order kinetic model (Formula 3). The adsorption effect and final adsorption rate of the magnetic ion-imprinted polymers on Sb(III) obtained after calculation and fitting are shown below. Figure 2 (a is a pseudo-first-order dynamic model, b is a pseudo-second-order dynamic model) and Figure 3 As shown in Tables 1 and 2, the pseudo-first-order and pseudo-second-order kinetic fitting parameters of the magnetic ion-imprinted polymer during the Sb(III) removal process are obtained.

[0050] Formula 1: q e =(C0-C)V / M, where q eThe adsorption amount of the magnetic ion-imprinted polymer on the target analyte at equilibrium is expressed in mg / g. C0 is the initial concentration of Sb(III) in mg / L, C is the equilibrium concentration of Sb(III) in mg / L, V is the volume of the Sb(III) solution in mL, and M is the amount of magnetic ion-imprinted polymer added in mg.

[0051] Formula 2: In the formula, q e The amount of adsorption of the target analyte by the magnetic ion-imprinted polymer at equilibrium is expressed in mg / g, q. t K is the adsorption amount at time t, in mg / g, and k1 is the pseudo-first-order rate constant, in min. -1 .

[0052] Formula 3: q t =(q e 2 k2t) / (1+q e k2t), where q e The amount of adsorption of the target analyte by the magnetic ion-imprinted polymer at equilibrium is expressed in mg / g, q. t t represents the amount of adsorption at time t, in mg / g, and k2 is the pseudo-second-order rate constant, in mg / (g / min).

[0053] Table 1. Pseudo-first-order dynamic fitting parameters

[0054] Table 2 Pseudo-second-order dynamic fitting parameters

[0055] Depend on Figure 2 and Figure 3 It can be seen that: within the first 60 minutes, the adsorption rates of Sb by IIP (2-IIP, 4-IIP, and M-IIP) and NIP are rapid; after 60 minutes, the adsorption rate decreases, and adsorption equilibrium is basically reached after 120 minutes; the goodness of fit (R0) of the pseudo-second-order kinetic models of each magnetic ion-imprinted polymer is shown to be... 2 The goodness of fit (R0) compared to the pseudo-first-order dynamics model 2 The higher adsorption capacity indicates that the adsorption mechanism is mainly chemical adsorption. From the perspective of theoretical adsorption saturation capacity, the maximum adsorption capacity of 2-IIP can reach 8.42 mg / g, which is significantly higher than other magnetic ion-imprinted polymers. The adsorption effect of non-imprinted material Fe3O4 is the worst, indicating that ion imprinting technology has more imprinted adsorption sites and can significantly improve the adsorption efficiency of Sb(III).

[0056] 3) 4 mg of the magnetic ion-imprinted polymers (2-IIP, 4-IIP, and M-IIP) from Examples 1-3 were added to 40 mL of a pentagonal mixed heavy metal wastewater (pH 2) with a Sb(III) concentration of 1 ppm and Fe, Cu, Mn, and Zn concentrations of 10 ppm, and to 40 mL of a binary mixed heavy metal wastewater (pH 5) with an arsenate concentration of 1 ppm and a phosphate concentration of 1 ppm. The solutions were then placed on a shaker at 25°C and 150 rpm for adsorption experiments. After 120 min, the supernatant was filtered through a 0.22 μm polyethersulfone filter, and the Sb concentration was determined using a flame atomic absorption spectrometer. The adsorption amount was calculated according to Formula 1, and the partition coefficient K was used. d The selective absorption performance of magnetic ion-imprinted polymers is evaluated using (Formula 4) and the selectivity coefficient K (Formula 5). d-Sb / K d-M >1 indicates preferential adsorption of Sb), the effect of metal cations on the Sb(III) removal efficiency of magnetic ion-imprinted polymers is shown in Table 3 (magnetic ion-imprinted polymers with Mn cations 2+ Cu 2+ Fe 2+ and Zn 2+ Specific adsorption test results under interference are as follows Figure 4 As shown in Table 4, the effect of oxygen-containing anions on the removal of Sb(III) by magnetic ion-imprinted polymers is shown in Table 4 (magnetic ion-imprinted polymers with AsO3 anions). 3- Specific adsorption test results under interference are as follows Figure 5 As shown, in the anion PO4 3- Specific adsorption test results under interference are as follows Figure 6 (As shown).

[0057] Formula 4: K d =Q e / C e In the formula, Q e The adsorption capacity of heavy metal ions at equilibrium is expressed in mg / g, C. e The concentration of heavy metal ions at equilibrium is expressed in mg / L.

[0058] Formula 5: K=K d-Sb / K d-M In the formula, K is the selectivity coefficient. d-Sb Let K be the allocation coefficient for Sb. d-M The sum of the partition coefficients of competing ions (representing Cu) 2+ +Zn 2+ +Fe 2+ +Mn 2+ AsO3 3- PO43- ).

[0059] Table 3. Effect of metal cations on the Sb(III) removal efficiency of magnetic ion-imprinted polymers

[0060] Table 4. Effect of oxygen-containing anions on the Sb(III) removal efficiency of magnetic ion-imprinted polymers

[0061] Depend on Figures 4-6 Tables 3 and 4 show that, despite interference from various cations and arsenate and phosphate groups with similar electronic configurations, the magnetic ion-imprinted polymers still exhibit high selectivity for Sb. Specifically, the partition coefficient of 2-IIP for Sb is significantly higher than that of competing ions, particularly in the Sb / Cu ratio. 2+ / Zn 2+ / Fe 2+ / Mn 2+ System, Sb / AsO3 3- System and Sb / PO4 3- The selectivity coefficients K in the system were 3.76, 21.91 and 21.55, respectively, indicating that it has the advantage of specific adsorption of Sb.

[0062] 4) 4 mg of the magnetic ion-imprinted polymer (2-IIP) from Example 1 was added to 40 mL of simulated heavy metal wastewater (pH 5) with an Sb(III) concentration of 1 ppm. The solution was then placed on a shaker at 25°C and 150 rpm for adsorption. After 120 min, the supernatant was filtered through a 0.22 μm polyethersulfone filter, and the Sb concentration was determined using flame atomic absorption spectrometry. The adsorption amount was calculated according to Formula 1. The magnetic ion-imprinted polymer was then filtered out and added to a 0.1 mol / L hydrochloric acid solution. The solution was then placed on a shaker at 25°C and 150 rpm for elution for 24 h. After freeze-drying, the adsorption experiment was repeated. A total of 5 adsorption experiments were conducted. The reusability test results of the obtained magnetic ion-imprinted polymer are shown below. Figure 7 As shown.

[0063] Depend on Figure 7 It can be seen that 2-IIP still maintains a high adsorption performance for Sb after 5 cycles, indicating that it has good regeneration ability and stability, and is suitable for repeated use in practical applications.

[0064] 5) 4 mg of the magnetic ion-imprinted polymer (2-IIP) from Example 1 was added to 40 mL of actual Sb-containing wastewater from a mining area (wastewater samples from six different sampling points in the Sb mining area, sampling locations being T2, T7, T8, T19, T21, and Q2, with wastewater quality indicators shown in Table 5). The sample was then placed on a shaker at 25°C and 150 rpm for adsorption. After 120 min, the supernatant was filtered through a 0.22 μm polyethersulfone filter, and the Sb concentration was determined using flame atomic absorption spectrometry. The adsorption amount was calculated according to Formula 1, and the Sb removal rate was calculated. The test results are shown in Table 5. Figure 8 As shown.

[0065] Table 5 Wastewater Quality Indicators Place initial Sb concentration( mg / L ） After adsorption Sb concentration( mg / L ） pH value T2 3.45 1.68 7.97 T7 0.21 0.037 8.17 T8 0.53 0.038 8.54 T19 1.15 0.26 7.71 T21 0.79 0 8.39 Q2 0.96 0 8.32 Depend on Figure 8 It can be seen that the Sb removal rate of wastewater samples at each sampling point exceeded 95%, and the Sb concentration in the wastewater decreased from the initial 0.21 mg / L to 3.45 mg / L to 0 mg / L to 1.68 mg / L, indicating that 2-IIP can still maintain excellent antimony removal performance in complex water environments.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a magnetic ion-imprinted polymer, characterized in that, Includes the following steps: 1) The functional monomer and template molecule are dispersed in a solvent for pre-assembly. The functional monomer is at least one of 4-vinylpyridine, hydroxyethyl methacrylate, and methacrylic acid, and the template molecule is at least one of potassium antimony tartrate and potassium antimony pyroantimonate, to obtain a complex solution. 2) Oleic acid-coated modified Fe3O4 particles, crosslinking agent and initiator were dispersed in a solvent and then added to the complex solution for polymerization to obtain a magnetic polymer; 3) The magnetic polymer was washed with an eluent to obtain a magnetic ion-imprinted polymer.

2. The preparation method according to claim 1, characterized in that: The ratio of the functional monomer, template molecule, oleic acid-coated modified Fe3O4 particles, and crosslinking agent is 1 mmol: 0.2 mmol to 0.3 mmol: 0.4 g to 0.6 g: 1.8 mmol to 2.2 mmol.

3. The preparation method according to claim 1 or 2, characterized in that: The solvent in step 1) is dimethyl sulfoxide.

4. The preparation method according to claim 1 or 2, characterized in that: Step 1) The pre-assembly is carried out at a temperature of 30℃~70℃ for a time of 0.5h~2h.

5. The preparation method according to claim 1 or 2, characterized in that: Step 2) The oleic acid-coated modified Fe3O4 particles are prepared by a method including the following steps: dispersing Fe3O4 particles in oleic acid, washing with ethanol, and then drying.

6. The preparation method according to claim 1 or 2, characterized in that: The crosslinking agent in step 2) is ethylene glycol dimethacrylate; the initiator in step 2) is azobisisobutyronitrile; the solvent in step 2) is methanol.

7. The preparation method according to claim 1 or 2, characterized in that: Step 2) The polymerization reaction is carried out at a temperature of 50℃ to 80℃ for a reaction time of 15h to 30h.

8. The preparation method according to claim 1 or 2, characterized in that: Step 3) The eluent is a hydrochloric acid solution.

9. A magnetic ion-imprinted polymer, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. The application of the magnetic ion-imprinted polymer as described in claim 9 in the treatment of antimony-containing wastewater.

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