Preparation method of molecularly imprinted magnetic cellulose gel microspheres
By modifying magnetic cellulose gel microspheres with β-cyclodextrin and synthesizing them through molecular imprinting technology, the problem of poor adsorption effect of phenolic substances in the prior art is solved, efficient adsorption and selectivity are achieved, and treatment costs are reduced.
Patent Information
- Application Number
- CN202510073313.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2025-04-25
AI Technical Summary
The prior art has poor adsorption effect when treating phenolic substances in petrochemical wastewater, and the binding sites of traditional molecularly imprinted polymers are unevenly distributed, resulting in low adsorption efficiency.
β-cyclodextrin is used as a functional monomer to modify magnetic cellulose gel microspheres, and molecularly imprinted polymers are synthesized through molecular imprinting technology to improve the distribution uniformity of adsorption sites and adsorption-desorption rate.
The adsorption capacity and selectivity of phenolic substances are significantly improved, efficient treatment of phenol-containing wastewater is achieved, and the material treatment cost is reduced through the introduction of magnetic nanoparticles.
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Figure CN119869475A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for preparing molecularly imprinted magnetic cellulose gel microspheres. Background Art
[0002] Petrochemical wastewater refers to wastewater discharged from petrochemical plants. Its components are complex and varied. It contains high levels of organic matter and its derivatives, and contains a variety of heavy metals. Phenol-containing wastewater mainly comes from atmospheric and vacuum, catalytic cracking, delayed coking, electro-refining and stacking devices. If it is not treated, it is very harmful and has a wide range of pollution, which will have serious impacts on human body, crops and natural water bodies.
[0003] Traditional treatment methods include physical adsorption, solvent extraction, chemical precipitation and biochemical methods. Chemical and biochemical methods often have problems such as low efficiency, high cost or secondary pollution. Physical adsorption is considered to be the preferred solution for wastewater treatment because of its advantages such as no secondary pollution during the adsorption process, simple operation, good adsorption effect, wide application range and varied use methods. It is widely used in wastewater treatment.
[0004] Molecular imprinting polymers have customized target recognition sites and excellent affinity and selectivity for specific molecules. They can be used as adsorption media in environmental governance fields such as physical adsorption treatment of wastewater. Molecular imprinting polymers are polymerized by molecular imprinting technology, which is inspired by the specific binding of antigens and antibodies. Currently, most molecular imprinting polymers used for pollutant adsorption are synthesized using conventional functional monomers such as acrylic acid and acrylamide, which have weak binding ability with template molecules and low specificity. In addition, most molecular imprinting polymers are synthesized by one-pot thermal polymerization. The resulting molecular imprinting polymers have problems such as uneven distribution of binding sites and excessive embedding, which leads to low efficiency of binding sites, directly affecting the adsorption treatment effect of wastewater. Summary of the invention
[0005] The purpose of the present invention is to solve the above technical problems and provide a method for preparing molecularly imprinted magnetic cellulose gel microspheres. The magnetic cellulose gel microspheres are modified with β-cyclodextrin as a functional monomer, and molecularly imprinted polymers are synthesized by molecular imprinting technology, thereby improving the adsorption capacity and selectivity of the magnetic gel microspheres for phenolic substances in wastewater, and having a better treatment effect on phenol-containing wastewater.
[0006] The method for preparing molecularly imprinted magnetic cellulose gel microspheres in the technical solution of the present invention comprises the following steps: (1) Adding cellulose microspheres to a magnetic ion solution, allowing the solution to react in ammonia at room temperature, and filtering and separating to obtain magnetic cellulose gel microspheres; (2) The template molecule, functional monomer, and β-cyclodextrin are added to the dispersion of magnetic cellulose gel microspheres and mixed evenly, and then a cross-linking agent and an initiator are added to carry out polymerization reaction, and finally desorption is carried out.
[0007] β-cyclodextrin has a cone-barrel structure, with a hydrophobic inner cavity and a hydrophilic outer surface. The cavity is of moderate size and can form stable inclusion complexes with a variety of guest molecules (phenol, etc.) through host-guest supramolecular interactions. Its binding ability is superior to traditional non-covalent interactions. Using β-cyclodextrin as a functional monomer to modify magnetic cellulose gel microspheres and then synthesizing molecular imprinting polymers through molecular imprinting technology can not only increase the adsorption rate of template molecules, but also achieve specific adsorption, and have a good treatment effect on phenol-containing wastewater. The introduction of magnetic nanoparticles makes the cellulose gel microsphere material easy to recycle and reduces the treatment cost.
[0008] Furthermore, the magnetic ions in step (1) are ferric ions and cobalt ions or ferrous ions mixed in a molar ratio of 1 to 5:1.
[0009] Preferably, the iron ions and the cobalt ions or the ferrous ions are derived from any one of the corresponding chlorides and sulfides.
[0010] Furthermore, the molar concentration of the magnetic ions in the magnetic ion solution in step (1) is 0.01-0.5 mol / L.
[0011] Preferably, the solvent of the magnetic ion solution is water.
[0012] Furthermore, in step (1), the mass ratio of cellulose microspheres to magnetic ion solution is 1:20-50.
[0013] Furthermore, in step (1), the reaction time in ammonia gas at room temperature is 10 to 30 hours.
[0014] Preferably, in step (1), the magnetic cellulose gel microspheres are separated by a magnet and rinsed with water.
[0015] Furthermore, in step (2), the template molecule is a phenolic compound, including but not limited to one or more of phenol, p-methylphenol, and p-tert-butylphenol.
[0016] Furthermore, the functional monomer in step (2) is an acrylic compound, including but not limited to one or more of acrylic acid, methacrylic acid, methyl methacrylate, and acrylamide.
[0017] Preferably, the cross-linking agent in step (2) includes, but is not limited to, one or more of N,N-methylenebisacrylamide, diethylenetriamine, and 2-ethyl-4-methylimidazole.
[0018] Preferably, the initiator in step (2) is a peroxide initiator, including but not limited to one or more of potassium persulfate, hydrogen peroxide, and ammonium persulfate.
[0019] Preferably, the molecular structure of the β-cyclodextrin in step (2) contains a carbon-carbon double bond, including but not limited to one or more of 6-acrylamide-β-cyclodextrin, N-isopropylacrylamide-β-cyclodextrin, and 6-acetylamino-β-cyclodextrin.
[0020] Furthermore, in step (2), the masses of the magnetic cellulose gel microspheres, the template molecules, the functional monomers and the β-cyclodextrin are 5-10 parts, 0.5-2.0 parts, 1.0-5.0 parts and 1.0-5.0 parts respectively.
[0021] Furthermore, the total mass of the magnetic cellulose gel microspheres, the template molecules, the functional monomers and β-cyclodextrin is not less than 10 parts.
[0022] Preferably, the solvent of the dispersion of magnetic cellulose gel microspheres in step (2) is water, wherein the mass fraction of the magnetic cellulose gel microspheres is 5-10%.
[0023] Furthermore, in step (2), the mass of the cross-linking agent is 0.1-1.0% of the sum of the mass of the functional monomer and the mass of β-cyclodextrin.
[0024] Furthermore, in step (2), the mass of the initiator is 0.5-1.5% of the sum of the mass of the functional monomer and β-cyclodextrin.
[0025] Furthermore, in step (2), the polymerization reaction temperature is 50-70° C., and the reaction time is 4-6 h.
[0026] Preferably, in step (2), desorption is performed until no phenol is detected in the desorption solution, and the desorption solution is a mixed solution of ethanol and acetic acid, wherein the volume ratio of ethanol to acetic acid is 0.5-1.5: 0.5-1.5.
[0027] The invention also provides molecularly imprinted magnetic cellulose gel microspheres, which are prepared by the preparation method of the molecularly imprinted magnetic cellulose gel microspheres.
[0028] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) The present invention uses β-cyclodextrin as a functional monomer to modify magnetic cellulose gel microspheres, and then synthesizes molecular imprinting polymers through molecular imprinting technology to obtain molecular imprinted magnetic cellulose gel microspheres; (2) By utilizing supramolecular effects and surface molecular imprinting technology, the distribution uniformity of adsorption sites and the adsorption-desorption rate were improved. The resulting molecularly imprinted magnetic cellulose gel microspheres have high adsorption efficiency and selectivity and can effectively enrich and separate phenol from phenol-containing wastewater. (3) β-cyclodextrin has a cone-barrel structure with a hydrophobic inner cavity and a hydrophilic outer surface. The cavity size is moderate and it can form stable inclusion complexes with a variety of guest molecules (phenol, etc.) through host-guest supramolecular interactions. As a functional monomer to modify magnetic cellulose gel microspheres, it can not only increase the adsorption rate of template molecules, but also achieve specific adsorption. (4) The introduction of magnetic nanoparticles makes the obtained molecularly imprinted magnetic cellulose gel microsphere material easy to recycle, thus reducing the processing cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 This is a data diagram of the adsorption selectivity of the molecularly imprinted magnetic cellulose gel microspheres obtained in Example 1 and Comparative Example 3. DETAILED DESCRIPTION
[0030] The technical scheme of the present invention is further described below by specific examples and accompanying drawings. It should be understood that the specific examples described herein are only used to help understand the present invention and are not intended for specific limitations of the present invention. The accompanying drawings used herein are only for better illustrating the disclosed content of the present invention and do not have a limiting effect on the scope of protection. If not otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.
[0031] The cellulose microspheres used in the following examples and comparative examples are from Xi'an Qiyue Biotechnology Co., Ltd.
[0032] Example 1
[0033] The method for preparing molecularly imprinted magnetic cellulose gel microspheres in this embodiment comprises the following steps: (1) Add 50 g of cellulose microspheres to 1000 mL of a mixed solution containing FeCl3+ and CoCl2, where the molar concentrations of Fe3+ and Co2+ are 0.2 mol / L and 0.1 mol / L, respectively. Allow the mixture to react in ammonia gas at room temperature for 24 h. After filtration, separate the magnetic cellulose gel microspheres with a magnet and rinse with water. (2) Disperse 5 g of magnetic cellulose gel microspheres in 100 mL of deionized water, add 1.0 g of phenol, 2.0 g of acrylamide, and 4.0 g of 6-acrylamide-β-cyclodextrin and mix well, then add 30 mg of N,N-methylenebisacrylamide and 60 mg of potassium persulfate, and polymerize at 60 °C for 6 h. Finally, desorb with ethanol-acetic acid solution with a volume ratio of ethanol to acetic acid of 1:1 until no phenol is detected in the desorption solution.
[0034] Example 2
[0035] The method for preparing molecularly imprinted magnetic cellulose gel microspheres in this embodiment comprises the following steps: (1) 40 g of cellulose microspheres were added to 1000 mL of a mixed solution containing FeCl3 and FeCl2, where the molar concentrations of Fe3+ and Fe2+ were 0.2 mol / L and 0.1 mol / L, respectively. The mixture was allowed to react in ammonia gas at room temperature for 24 h. After filtration, the magnetic cellulose gel microspheres were separated using a magnet and rinsed with water. (2) Disperse 6 g of magnetic cellulose gel microspheres in 100 mL of deionized water, add 1.0 g of p-methylphenol, 2.0 g of methacrylic acid, and 4.0 g of N-isopropylacrylamide-β-cyclodextrin and mix well, then add 30 mg of N,N-methylenebisacrylamide and 60 mg of potassium persulfate, and polymerize at 65 °C for 6 h. Finally, desorb with ethanol-acetic acid solution with a volume ratio of ethanol to acetic acid of 1:1 until no phenol is detected in the desorption solution.
[0036] Example 3
[0037] The method for preparing molecularly imprinted magnetic cellulose gel microspheres in this embodiment comprises the following steps: (1) Add 50 g of cellulose microspheres to 1000 mL of a mixed solution containing FeCl3+ and CoCl2, where the molar concentrations of Fe3+ and Co2+ are 0.30 mol / L and 0.15 mol / L, respectively. Allow the mixture to react in ammonia gas at room temperature for 24 h. After filtration, separate the magnetic cellulose gel microspheres with a magnet and rinse with water. (2) Disperse 8 g of magnetic cellulose gel microspheres in 100 mL of deionized water, add 1.0 g of p-methylphenol, 2.0 g of methacrylic acid, and 2.0 g of 6-acrylamide-β-cyclodextrin and mix well, then add 20 mg of N,N-methylenebisacrylamide and 40 mg of ammonium persulfate, and polymerize at 70 °C for 6 h. Finally, desorb with ethanol-acetic acid solution with a volume ratio of ethanol to acetic acid of 1:1 until no phenol is detected in the desorption solution.
[0038] Example 4
[0039] The difference between this embodiment and embodiment 1 is that in step (2), 5 g of magnetic cellulose gel microspheres are dispersed in 100 mL of deionized water, 2.0 g of phenol, 2.0 g of acrylamide, and 2.0 g of 6-acrylamide-β-cyclodextrin are added and mixed evenly, and then 20 mg of N,N-methylenebisacrylamide and 40 mg of potassium persulfate are added, and polymerization reaction is carried out at 60° C. for 6 h, and finally desorption is carried out with ethanol-acetic acid solution, the volume ratio of ethanol to acetic acid being 1:1, until phenol is no longer detected in the desorption solution.
[0040] Example 5
[0041] The difference between this embodiment and embodiment 1 is that in step (2), 5 g of magnetic cellulose gel microspheres are dispersed in 100 mL of deionized water, 2.0 g of phenol, 3.0 g of acrylamide, and 0.5 g of 6-acrylamide-β-cyclodextrin are added and mixed evenly, and then 30 mg of N,N-methylenebisacrylamide and 60 mg of potassium persulfate are added, and polymerization reaction is carried out at 60° C. for 6 h, and finally desorption is carried out with ethanol-acetic acid solution, the volume ratio of ethanol to acetic acid being 1:1, until phenol is no longer detected in the desorption solution.
[0042] Example 6
[0043] The difference between this embodiment and embodiment 1 is that in step (2), 5 g of magnetic cellulose gel microspheres are dispersed in 100 mL of deionized water, 1.0 g of phenol, 2.0 g of acrylamide, and 6.0 g of 6-acrylamide-β-cyclodextrin are added and mixed evenly, and then 30 mg of N,N-methylenebisacrylamide and 80 mg of potassium persulfate are added, and polymerization reaction is carried out at 60° C. for 6 h, and finally desorption is carried out with ethanol-acetic acid solution, the volume ratio of ethanol to acetic acid being 1:1, until phenol is no longer detected in the desorption solution.
[0044] Comparative Example 1 The preparation method of molecularly imprinted magnetic cellulose gel microspheres in this comparative example comprises the following steps: 5 g of cellulose microspheres were dispersed in 100 mL of deionized water, and 1.0 g of phenol, 2.0 g of acrylamide, and 4.0 g of 6-acrylamide-β-cyclodextrin were added and mixed evenly. Then 30 mg of N,N-methylenebisacrylamide and 60 mg of potassium persulfate were added, and the polymerization reaction was carried out at 60 ° C for 6 h. Finally, ethanol-acetic acid solution was used for desorption, and the volume ratio of ethanol to acetic acid was 1:1, until phenol was no longer detected in the desorption solution.
[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that in step (2), 5 g of magnetic cellulose gel microspheres are dispersed in 100 mL of deionized water, 1.0 g of phenol and 2.0 g of acrylamide are added and mixed evenly, 30 mg of N,N-methylenebisacrylamide and 60 mg of potassium persulfate are added, polymerization reaction is carried out at 60° C. for 6 h, and finally desorption is carried out with ethanol-acetic acid solution, the volume ratio of ethanol to acetic acid is 1:1, until phenol is no longer detected in the desorption solution.
[0046] Comparative Example 3 The difference between this comparative example and Example 1 is that in step (2), 8 g of magnetic cellulose gel microspheres are dispersed in 100 mL of deionized water, 2.0 g of acrylamide and 2.0 g of 6-acrylamide-β-cyclodextrin are added and mixed evenly, and then 20 mg of N,N-methylenebisacrylamide and 40 mg of potassium persulfate are added, and polymerization reaction is carried out at 60° C. for 6 h, and finally desorption is carried out with ethanol-acetic acid solution, the volume ratio of ethanol to acetic acid is 1:1, until phenol is no longer detected in the desorption solution.
[0047] The molecularly imprinted magnetic cellulose gel microspheres obtained in the above embodiments and comparative examples were subjected to adsorption performance test and adsorption selectivity test, wherein the adsorption performance test was performed by weighing 10 mg of cellulose gel microspheres and placing them into 1000 mL of a phenol solution with a phenol concentration of 150 mg / L, stirring and adsorbing them with a magnetic stirrer, and sampling and analyzing the concentration of phenol in the solution every 30 minutes, and the results are shown in Table 1; the adsorption selectivity test was performed by taking hydroquinone, p-nitrophenol and p-tert-butylphenol, which are common and structurally similar in petrochemical wastewater, as interfering molecules, and determining the adsorption selectivity of the gel microspheres for phenol: a mixed solution of hydroquinone, p-nitrophenol, p-tert-butylphenol and phenol was prepared, with a mass concentration of 150 mg / L, 10 mg of cellulose gel microspheres was weighed and placed into 1000 mL of the solution, stirring and adsorbing them with a magnetic stirrer, and sampling and analyzing the concentrations of various phenolic substances in the solution every 30 minutes.
[0048]
[0049] As shown in Table 1, the molecularly imprinted magnetic cellulose gel microspheres obtained in Examples 1-4 have a faster adsorption rate and a higher equilibrium adsorption amount because the molecular imprinting technology can improve the uniformity of the distribution of adsorption sites, thereby improving the efficiency of the adsorption sites in the cellulose gel microspheres and increasing the adsorption rate. At the same time, it can also improve the utilization rate of the adsorption sites, making the equilibrium adsorption amount higher; like Figure 1As shown, compared with the magnetic cellulose gel microspheres synthesized in Comparative Example 3 without using molecular imprinting technology, the gel microspheres synthesized in Example 1 using molecular imprinting technology have higher adsorption selectivity. This is because molecular imprinting technology can create specific adsorption sites, thereby improving the specific selectivity of adsorption.
[0050] In Example 5, less β-cyclodextrin is used to modify the magnetic cellulose gel microspheres, and the adsorption rate of the obtained magnetic cellulose gel microspheres for the template molecules is reduced, and the specific adsorption performance is also reduced; in Example 6, an excess of β-cyclodextrin is used to modify the magnetic cellulose gel microspheres, and the excess β-cyclodextrin cannot be effectively repaired on the magnetic cellulose gel microspheres, and the distribution is uneven, which reduces the adsorption selectivity of the molecularly imprinted magnetic cellulose gel microspheres; in Comparative Example 1, no magnetic ions are added, and the cellulose microspheres are directly modified with β-cyclodextrin, and the obtained cellulose gel microspheres are not easy to separate; in Comparative Example 2, β-cyclodextrin is not used to modify the magnetic cellulose gel microspheres, and the adsorption rate and specific adsorption performance of the obtained magnetic cellulose gel microspheres for the template molecules are sharply reduced; in Comparative Example 3, molecular imprinting technology is not used to synthesize gel microspheres, and the obtained magnetic cellulose gel microspheres have no specific adsorption points and poor adsorption selectivity.
[0051] Finally, it should be noted that the specific embodiments described herein are merely examples of the spirit of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art of the present invention may make various modifications or supplements to the described embodiments or replace them in similar ways. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.
Claims
1. A method for preparing molecularly imprinted magnetic cellulose gel microspheres, characterized in that: The following steps are involved: (1) Adding cellulose microspheres to a magnetic ion solution, allowing the solution to react in ammonia at room temperature, and filtering and separating to obtain magnetic cellulose gel microspheres; (2) The template molecule, functional monomer, and β-cyclodextrin are added to the dispersion of magnetic cellulose gel microspheres and mixed evenly, and then a cross-linking agent and an initiator are added to carry out polymerization reaction, and finally desorption is carried out.
2. The preparation method according to claim 1, characterized in that: In step (1), the magnetic ions are ferric ions and cobalt ions or ferrous ions mixed in a molar ratio of 1 to 5:
1.
3. The preparation method according to claim 1, characterized in that: The molar concentration of the magnetic ions in the magnetic ion solution in step (1) is 0.01-0.5 mol / L.
4. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of cellulose microspheres to magnetic ion solution is 1:20-50.
5. The preparation method according to claim 1, characterized in that: In step (2), the template molecule is a phenolic compound; and / or the functional monomer is an propylene compound.
6. The preparation method according to claim 1, characterized in that: In step (2), the masses of magnetic cellulose gel microspheres, template molecules, functional monomers and β-cyclodextrin are 5-10 parts, 0.5-2.0 parts, 1.0-5.0 parts and 1.0-5.0 parts respectively.
7. The preparation method according to claim 1, characterized in that: The mass of the cross-linking agent in step (2) is 0.1-1.0% of the sum of the mass of the functional monomer and β-cyclodextrin.
8. The preparation method according to claim 1, characterized in that: The mass of the initiator in step (2) is 0.5-1.5% of the sum of the mass of the functional monomer and β-cyclodextrin.
9. The preparation method according to claim 1, characterized in that: The polymerization reaction temperature in step (2) is 50-70° C., and the reaction time is 4-6 hours.
10. A molecularly imprinted magnetic cellulose gel microsphere, characterized in that: The method is prepared according to claim 1.