Preparation method and application of high-activity hierarchical pore boric acid imprinted hydrogel microsphere adsorbent

Abstract

The invention discloses a preparation method of a high-activity hierarchical pore boric acid imprinted hydrogel microsphere adsorbent and application of the adsorbent to selective adsorption of a flavonoid compound naringin NRG. According to the invention, dopamine is used for modifying COFs so as to enhance surface functionalization of COFs; preparing a sulfydryl functionalized covalent organic framework microsphere; synthesizing sulfydryl microspheres by utilizing an emulsion interfacial polymerization method; preparing a COFs boron affinity imprinting microsphere adsorbent based on boron affinity interaction; the adsorbent is applied to selective adsorption of NRG in agricultural wastewater. The prepared adsorbent has a remarkable multilayer adsorption effect, and the adsorption capacity is remarkably improved through the boron affinity effect. The multi-stage pore structure of the COFs microspheres provides abundant sites for adsorption, and the mass transfer rate is remarkably improved. In addition, the prepared adsorbent shows remarkable specificity in the aspects of adsorption and separation of NRG, and a promising adsorption material is provided for industrial separation of NRG.

Description

Technical Field

[0001] The invention belongs to the field of environmental materials and relates to a preparation method of a multi-level pore structure boric acid affinity imprinted hydrogel microsphere adsorbent based on an emulsion template method through emulsion interface cross-linking interaction and an application thereof in the purification of agricultural environmental waste naringin. Background Art

[0002] Naringin is a bioactive compound that is abundantly present in byproducts of citrus fruit processing. The content of naringin in different parts of pomelo varies greatly, with the content of naringin in the peel accounting for about 70% of the total naringin content in the whole fruit. Naringin has excellent biomedical and industrial properties, such as antioxidant, anticancer, anti-inflammatory, improvement and alleviation of diabetes and its complications, and lowering of blood levels. However, how to effectively extract naringin from agricultural environmental waste is a major research hotspot. Traditional extraction techniques such as adsorption, Soxhlet, immersion and reflux methods are usually energy-intensive or require large amounts of organic solvents and long, non-reusable, costly, time-consuming, poor selectivity and negative environmental impact. The molecular structure of naringin promotes the development of borate affinity, forming a specific reversible covalent bond with the cis-dihydroxy structure of naringin (NRG). This innovative approach opens up new possibilities for the preparation of boron affinity adsorbents to separate NRG. Molecularly imprinted polymers (MIPs) have gained great attention in the field of separation technology. This is largely due to their innate ability to accurately recognize target molecules, as well as their excellent stability, wide range of applications and general appeal. Therefore, boron affinity and molecular imprinting polymers are combined to take advantage of the advantages of accessible specific surface-oriented recognition sites and rapid mass transfer kinetics. High specificity and selectivity for the target (NRG) are achieved by utilizing the boric acid affinity imprinting recognition sites. In addition, the rapid mass transfer kinetics enable efficient and rapid capture of boron affinity imprinted polymers, which are very suitable for NRG selective separation applications. The affinity materials that have been developed include cellulose nanocrystals, SiO2, carbon nanotubes, metal organic frameworks, etc. However, most of the above have defects such as small specific surface area, slow mass transfer rate, and inaccessible contact sites, resulting in low adsorption performance.

[0003] Covalent organic frameworks (COFs), as an important member of the porous material family, are formed by covalent bonds of molecular organic building blocks and have attracted increasing attention in recent years. COFs are widely used in specific adsorption due to their advantages such as good stability, large specific surface area, easy functionalization and permanent porosity. Microspheres (MCs) are a class of nanomaterials with hollow spherical structures. They have significant structural stability, biocompatibility, selective permeability, etc. and are widely used in drug delivery, molecular screening, and separation technology. Therefore, boron affinity imprinted adsorbents were prepared by combining COFs with microspheres through COFs functional group modification.

[0004] Pickering emulsion is an emulsion stabilized by solid particles instead of surfactants. Compared with traditional emulsions, Pickering emulsions have their unique advantages. For example, compared with surfactants, solid particles have higher adsorption energy and ability to stabilize emulsions, so less amount is needed. Based on this, Pickering emulsions have been widely used in the field of adsorption. Pickering particles are tightly fixed between the oil and water interface, which can inhibit the aggregation of particles, provide the maximum specific surface area for catalysts, and improve the adsorption efficiency. Summary of the invention

[0005] In view of a series of defects in existing separation and extraction technologies, the present invention proposes a separation material-level preparation method with extremely high specific adsorption capacity for NRG. The technology is briefly described as follows: First, functionalized thiol COFs microspheres (BTCA-COF@-MC) are prepared through an emulsion interface assembly strategy, and then the ATRP initiator with a double bond is modified on its surface through a simple hot solvent method to provide accessible active sites for its subsequent ATRP imprinting. Finally, boric acid is used as a functional monomer and NRG is used as a template molecule through pre-assembly to prepare an imprinting cavity with NRG specificity, and COFs borate affinity imprinting microspheres are prepared by ATRP.

[0006] The preparation method of a high-activity multi-level porous boric acid imprinted hydrogel microsphere adsorbent comprises the following steps:

[0007] (1) 1,3,5-tri(4-aminophenyl)benzene and 1,3,5-triformaldehydebenzene are dissolved in a three-necked flask containing acetonitrile, and chiral phosphate-based benzaldehydeaniline is added, and ultrasonic dispersion is performed in a water bath; then, under nitrogen protection, acetonitrile containing Sc(OTfs)3 is continuously added, and mechanical stirring is performed for the first time; then, the obtained product BTCA-COFs is washed with acetonitrile and vacuum dried;

[0008] Dopamine hydrochloride was dissolved in Tris-HCl buffer and the pH was adjusted with sodium hydroxide solution; then, BTCA-COFs were added to the solution and stirred for a second time; subsequently, the resulting product was washed several times with methanol, centrifuged, and dried, and named BTCA-COF@PDA.

[0009] (2) BTCA-COF@PDA was dispersed in ultrapure water, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added. After stirring, thioglycolic acid was added and the mixture was stirred. Finally, the obtained sample was washed with ultrapure water and vacuum dried. The final product was named BTCA-COF@PDA-SH.

[0010] (3) BTCA-COF@PDA-SH was uniformly dispersed in mesitylene, and then Sc(OTf)3 was added dropwise. The mixture was sheared at high speed to obtain a stable oil-in-water (O / W) Pickering emulsion.

[0011] (4) The Pickering emulsion was transferred to a centrifuge tube and mesitylene was added. Subsequently, 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-triformaldehydebenzene were dissolved in chloroform, and then the competing substances benzaldehyde and aniline were added to prepare an emulsion dispersion. The mixed solution was placed in a centrifuge tube and allowed to stand at room temperature. The obtained microspheres were named MC BTCA-COF@PDA-SH.

[0012] (5) The functional monomer 3-acrylamidophenylboronic acid, the template molecule NRG and methanol were added to a flask, mixed and stirred for pre-assembly; then polydipentaerythritol pentaacrylate and benzoin dimethyl ether were added and ultrasonically treated; subsequently, the prepared MC BTCA-COF@PDA-SH was added to the mixed solvent and treated with nitrogen to prevent oxidation; the molecular imprinting polymerization was initiated by ultraviolet light, and after the reaction, the template molecule NRG was removed by washing with methanol and acetic acid solution, and then washed with ethanol and deionized water several times, respectively. The final product was dried in an oven to obtain a highly active multi-level porous boric acid imprinted hydrogel microsphere adsorbent, referred to as MC@PDA-SH@BA-MIPs.

[0013] In step (1), the dosage ratio of 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-triformaldehydebenzene, acetonitrile, chiral phosphate benzaldehyde, aniline and Sc(OTfs)3 is 17.6 mg:8.1 mg:39 mL:60.8 μL:54.4 μL:11.8 mg; the time of ultrasonic water bath dispersion is 30 minutes; the temperature of the first mechanical stirring is 25°C and the time is 24 h; the temperature of vacuum drying is 60°C and the drying time is 24 h.

[0014] In step (1), the ratio of BTCA-COFs to dopamine hydrochloride is 100 mg:75 mg; the concentration of Tris-HCl buffer is 10 mmol / L; the pH of the sodium hydroxide solution is adjusted to 8.5; the temperature of the second stirring is 25° C. and the time is 6 h.

[0015] In step (2), the usage ratio of BTCA-COF@PDA, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and thioglycolic acid is 20 mg: 10 mL: 10 mL: 52 μL.

[0016] In step (2), after adding thioglycolic acid, the mixture was stirred at 25° C. for 12 h.

[0017] In step (3), the usage ratio of BTCA-COF@PDA-SH, mesitylene and Sc(OTf)3 is 1.7 mg:4.0 mL:0.2 mL.

[0018] In step (3), the high-speed shearing rate is 15000 rpm and the shearing time is 3 min.

[0019] In step (4), the amount ratio of Pickering emulsion, mesitylene, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-triformaldehydebenzene, chloroform, benzaldehyde and aniline is 2.0mL:4.0mL:3.5mg:1.6mg:2.0mL:12.1μL:10.8μL; and the standing time at room temperature is 24h.

[0020] In step (5), the usage ratio of 3-acrylamidophenylboronic acid, NRG, methanol, polydipentaerythritol pentaacrylate, benzoin dimethyl ether, and MC BTCA-COF@PDA-SH is 38 mg: 29 mg: 20.0 mL: 58 mg: 20 mg: 80 mg.

[0021] In step (5), the preassembly time is 3.0 h, the ultrasonic treatment time is 10 min, the nitrogen treatment time is 30 min, the molecular imprinting polymerization is initiated by 365 nm ultraviolet light for 60 min, and the volume ratio of methanol to acetic acid in the methanol and acetic acid solution is 9:1.

[0022] Furthermore, the drying temperature of the present invention is 40-60° C., and the drying time is not less than 12 hours.

[0023] As a control, non-imprinted microspheres (MC@PDA-SH@BA-NIPs) were prepared by the same method without adding NRG.

[0024] The high-activity multi-level porous boric acid imprinted hydrogel microsphere adsorbent MC@PDA-SH@BA-MIPs prepared by the present invention is used for adsorbing and separating the flavonoid compound naringin NRG.

[0025] The above technical solution is only an optimal feasible technical solution presented by the present invention. The protection scope of the present invention is not limited thereto. Professional and technical personnel in this field can reasonably adjust the technical design according to actual needs.

[0026] The adsorption principle of the present invention is:

[0027] The adsorbent of the present invention can selectively capture NRG from a waste solution of numerous cis-dihydroxy interfering substances, that is, NRG selectively forms a NRG-boric acid five-membered ring or a six-membered ester ring with the adsorbent, and other interfering substances remain in the original solution. This is because NRG can specifically bind to the specific imprinted cavity formed by the adsorbent, and due to covalent / non-covalent effects, it can highly selectively adsorb NRG in agricultural wastewater, while other interfering substances cannot enter the imprinted cavity and are retained in the waste solution, thereby achieving the purpose of improving selective adsorption.

[0028] The beneficial effects of the present invention are:

[0029] (1) The present invention prepares COFs boron affinity imprinted microspheres based on emulsion interfacial polymerization. The adsorbent has abundant multi-layer boron affinity imprinting sites and presents an obvious interface structure of particle adsorption.

[0030] (2) The adsorbent of the present invention is a spherical adsorbent, which has the characteristics of good stability, low dissolution rate, high adsorption capacity, and multiple mass transfer sites.

[0031] (3) The adsorbent prepared by the present invention adopts commercial raw materials, has a simple process and wide adaptability, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly explain the technical path of the present invention, the drawings used in the embodiments (Embodiment 1, Embodiment 2, Embodiment 1) are introduced below. The drawings in the following description are used as embodiments of the present invention. Those skilled in the art can obtain the drawings according to their needs without paying creative labor. Among them:

[0033] Figure 1 TEM images (a1, a2) of BTCA-COF@PDA-SH in Example 1;

[0034] Figure 2 Scanning images (b1, b2) of MC@PDA-SH@BA-MIPs (a1, a2) and MC@PDA-SH@BA-NIPs prepared in Example 1;

[0035] Figure 3 This is the energy spectrum analysis diagram of the MC@PDA-SH@BA-MIPs adsorbent prepared in Example 1;

[0036] Figure 4 Infrared spectra of MC@PDA-SH@BA-MIPs and MC@PDA-SH@BA-NIPs prepared in Example 1

[0037] Figure 5The adsorption kinetics fitting curves of MC@PDA-SH@BA-MIPs (a) and MC@PDA-SH@BA-NIPs (b) prepared in Example 1;

[0038] Figure 6 It is the adsorption isotherm curve of the boron affinity microsphere molecular imprinting adsorbent (MC@PDA-SH@BA-MIPs) in Example 2;

[0039] Figure 7 This is a competitive adsorption bar chart of the boron affinity microsphere molecular imprinting adsorbent (MC@PDA-SH@BA-MIPs and MC@PDA-SH@BA-NIPs) in Example 3. DETAILED DESCRIPTION

[0040] In order to make the research purpose, features, and results of the present invention more understandable, the examples of the present invention are further explained in detail below in conjunction with the claims.

[0041] Example 1

[0042] (1) Preparation of BTCA-COF@PDA particles:

[0043] 1,3,5-tris(4-aminophenyl)benzene (17.6 mg) and 1,3,5-triformaldehydebenzene (8.1 mg) were dissolved in a three-necked flask containing 39 mL of acetonitrile, and chiral phosphate benzaldehyde (60.8 μL) and aniline (54.4 μL) were added, and dispersed in an ultrasonic water bath for 30 minutes. Subsequently, under nitrogen protection, acetonitrile containing Sc(OTfs)3 was added to the above solution, and mechanically stirred at 25°C for 24 hours. Subsequently, the resulting product (BTCA-COFs) was washed with acetonitrile and dried in a vacuum oven at 60°C for 24 hours. 75 mg of dopamine was dissolved in 50 mL of Tris-HCl buffer (concentration of 10 mmol / L), and the pH was adjusted to 8.5 with sodium hydroxide solution. Then, 100 mg of BTCA-COFs was added to the solution and stirred at 25°C for 6 hours. Subsequently, the resulting product was washed three times with methanol and centrifuged at 10,000 rpm. The product was dried in an oven and named BTCA-COF@PDA.

[0044] (2) Preparation of thiol-functionalized BTCA-COF@PDA-SH particles: 20 mg of BTCA-COF@PDA was dispersed in 30 mL of ultrapure water, and then 10 mL of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 10 mL of N-hydroxysuccinimide (6.0 mg / L) were added. After stirring for 2 h, 52 μL of thioglycolic acid was added to the above reaction system. The mixture was stirred at 25 °C for 12 h. Finally, the obtained sample was washed with ultrapure water and dried in a vacuum drying oven. The final product was named BTCA-COF@PDA-SH.

[0045] (3) Preparation of Pickering emulsion: First, 1.7 mg BTCA-COF@PDA-SH was uniformly dispersed in 4.0 mL trimethylol. Then, 0.2 mL Sc(OTf)3 was added dropwise to the mixture. The mixture was sheared at high speed to obtain a stable oil-in-water (O / W) Pickering emulsion.

[0046] (4) Preparation of COFs microspheres by emulsion interfacial polymerization:

[0047] Transfer 2 mL of Pickering emulsion to a centrifuge tube and add 4 mL of mesitylene. Subsequently, 3.5 mg of 1,3,5-tris(4-aminophenyl)benzene and 1.6 mg of 1,3,5-triformaldehydebenzene were dissolved in 2 mL of chloroform, and then competitors (12.1 μL of benzaldehyde and 10.8 μL of aniline) were added to prepare an emulsion dispersion. The mixed solution was placed in a 10 mL centrifuge tube and allowed to stand at room temperature for 24 h. The resulting microspheres were named MC BTCA-COF@PDA-SH.

[0048] (5) Preparation of COFs boron affinity imprinted microspheres: The functional monomer (3-acrylamidophenylboronic acid, 38 mg), template molecule (NRG, 29 mg) and methanol (20.0 mL) were added to a 50 mL flask and mixed and stirred for 3.0 h for pre-assembly. Then, 58 mg of polydipentaerythritol pentaacrylate and 20 mg of benzoin dimethyl ether were added and ultrasonically treated for 10 min. Subsequently, the prepared MCBTCA-COF@PDA-SH was added to the mixed solvent and treated with nitrogen for 30 min to prevent oxidation. Molecular imprinting polymerization was initiated by 365 nm UV light for 60 min. The prepared MC@PDA-SH@BA-MIPs imprinted microspheres were washed with methanol / acetic acid (9:1, v / v) solution to remove the template molecule NRG, and then washed several times with ethanol and deionized water respectively. The final product was dried in an oven. As a control, non-imprinted microspheres (MC@PDA-SH@BA-NIPs) were prepared by the same method, but without adding NRG.

[0049] like Figure 1As shown in the transmission image of BTCA-COF@PDA-SH, the size of the COFs monomer is about 120nm, the size is uniform and the surface is rough, which can be attributed to the growth of dopamine on the outer layer of COFs. In Figure a2, it can be seen that BTCA-COF@PDA-SH shows uniform pores.

[0050] like Figure 2 As shown in Figure 2, MC@PDA-SH@BA-MIPs and MC@PDA-SH@BA-NIPs exhibit uniform spherical morphology. Through layer-by-layer modification, the surface of the microspheres becomes rough and has many COFs particles. Imprinted microspheres and non-imprinted microspheres show similar morphologies, indicating that MC@PDA-SH@BA-MIPs were successfully synthesized.

[0051] like Figure 3 As shown in the energy spectrum analysis diagram, it can be seen that the C, N, O and B elements show obvious peaks in the binding energy, indicating that COFs boron affinity imprinted polymer microspheres MC@PDA-SH@BA-MIPs were successfully prepared by UV-photopolymerization.

[0052] like Figure 4 As shown in the infrared spectrum, it can be clearly seen that at 1389cm -1 The stretching peak of BO was shown, indicating that MC@PDA-SH@BA-MIPs were successfully synthesized by ATRP reaction of boric acid.

[0053] Example 2

[0054] 5 mg of MC@PDA-SH@BA-MIPs was weighed and added to 5 mL of NRG solution with a concentration of 35 mg / L and a pH value of 7.4, and then placed in a 308K water bath for oscillation. The contact time between the adsorbent and the solution was 5 to 360 min. The residual NRG concentration at each time point was determined by the UV-Vis method, and the adsorption capacity was calculated based on the measured results. Figure 5 As shown in the figure, MC@PDA-SH@BA-MIPs exhibited rapid adsorption characteristics from 0 to 120 minutes, and the adsorption rate gradually slowed down over time and tended to adsorption equilibrium at 120 minutes. This is because as time goes by, the imprinted cavity is gradually occupied by the target molecules, and the adsorption capacity continues to increase until it reaches a state of equilibrium.

[0055] Weigh 5 mg of MC@PDA-SH@BA-MIPs, add 5 mL of NRG solution (pH = 7.4) of different concentrations (10, 15, 25, 35, 50 mg / L), and oscillate in a constant temperature water bath at 25, 30 and 35 ° C for 360 minutes. After the adsorption reaction, the residual concentration of NRG was determined by UV-Vis method, and the adsorption capacity was calculated based on the measured data. The adsorption capacity of MC@PDA-SH@BA-MIPs was calculated by the same method. Figure 6 As shown in the figure, under different initial concentrations and temperatures, the adsorption capacity of the boron affinity porous microsphere imprinted adsorbent MC@PDA-SH@BA-MIPs gradually increases with the increase of temperature, indicating that the adsorption type of NRG on MC@PDA-SH@BA-MIPs is an endothermic reaction.

[0056] Example 3

[0057] 5.0 mg of MC@PDA-SH@BA-MIPs were immersed in 5.0 mL of the above-mentioned aqueous solution of hydroxyl compounds (pH = 7.4, concentration of 35 mg / L), including rutin, quercetin, o-nitrophenol, alizarin red and hydroquinone. Subsequently, the mixture was adsorbed in a 308K water bath for 6.0 hours. After the adsorption, the supernatant was separated by centrifugation, and the concentration of the competitive molecule was determined by UV-Vis method. Figure 7 As shown in the figure, compared with other competitors, MC@PDA-SH@BA-MIPs has a significantly stronger adsorption ability for NRG, which is attributed to the abundant imprinted recognition sites on its surface, indicating that the material has a significant specific recognition ability for NRG.

Claims

1. A method for preparing a highly active multi-level porous boric acid imprinted hydrogel microsphere adsorbent, characterized in that: The steps include: (1) 1,3,5-tri(4-aminophenyl)benzene and 1,3,5-triformaldehydebenzene are dissolved in a three-necked flask containing acetonitrile, and chiral phosphate-based benzaldehydeaniline is added, and ultrasonic dispersion is performed in a water bath; then, under nitrogen protection, acetonitrile containing Sc(OTfs)3 is continuously added, and mechanical stirring is performed for the first time; then, the obtained product BTCA-COFs is washed with acetonitrile and vacuum dried; Dopamine hydrochloride was dissolved in Tris-HCl buffer and the pH was adjusted with sodium hydroxide solution. Then, BTCA-COFs were added to the solution and stirred for a second time. Subsequently, the resulting product was washed several times with methanol, centrifuged, and dried, and named BTCA-COF@PDA. (2) BTCA-COF@PDA was dispersed in ultrapure water, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added. After stirring, thioglycolic acid was added and the mixture was stirred. Finally, the obtained sample was washed with ultrapure water and vacuum dried. The final product was named BTCA-COF@PDA-SH. (3) BTCA-COF@PDA-SH was uniformly dispersed in mesitylene, and then Sc(OTf)3 was added dropwise, and the mixture was sheared at high speed to obtain a stable oil-in-water (O / W) Pickering emulsion; (4) The Pickering emulsion was transferred to a centrifuge tube, and mesitylene was added. Subsequently, 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-triformaldehydebenzene were dissolved in chloroform, and then the competing substances benzaldehyde and aniline were added to prepare an emulsion dispersion. The mixed solution was placed in a centrifuge tube and allowed to stand at room temperature. The obtained microspheres were named MC BTCA-COF@PDA-SH. (5) The functional monomer 3-acrylamidophenylboronic acid, the template molecule NRG and methanol were added to a flask, mixed and stirred for pre-assembly; then polydipentaerythritol pentaacrylate and benzoin dimethyl ether were added and ultrasonically treated; subsequently, the prepared MC BTCA-COF@PDA-SH was added to the mixed solvent and treated with nitrogen to prevent oxidation; the molecular imprinting polymerization was initiated by ultraviolet light, and after the reaction, the template molecule NRG was removed by washing with methanol and acetic acid solution, and then washed with ethanol and deionized water several times, respectively. The final product was dried in an oven to obtain a highly active multi-level porous boric acid imprinted hydrogel microsphere adsorbent, referred to as MC@PDA-SH@BA-MIPs.

2. The preparation method according to claim 1, characterized in that In step (1), the dosage ratio of 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-triformaldehydebenzene, acetonitrile, chiral phosphate benzaldehyde, aniline and Sc(OTfs)3 is 17.6 mg:8.1 mg:39 mL:60.8 μL:54.4 μL:11.8 mg; the time of ultrasonic water bath dispersion is 30 minutes; the temperature of the first mechanical stirring is 25°C and the time is 24 h; the temperature of vacuum drying is 60°C and the drying time is 24 h.

3. The preparation method according to claim 1, characterized in that: In step (1), the ratio of BTCA-COFs to dopamine hydrochloride is 100 mg:75 mg; the concentration of Tris-HCl buffer is 10 mmol / L; the pH of the sodium hydroxide solution is adjusted to 8.5; the temperature of the second stirring is 25° C. and the time is 6 h.

4. The preparation method according to claim 1, characterized in that: In step (2), the ratio of BTCA-COF@PDA, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and thioglycolic acid is 20 mg: 10 mL: 10 mL: 52 μL; In step (2), after adding thioglycolic acid, the mixture was stirred at 25° C. for 12 h.

5. The preparation method according to claim 1, characterized in that: In step (3), the dosage ratio of BTCA-COF@PDA-SH, mesitylene and Sc(OTf)3 is 1.7 mg:4.0 mL:0.2 mL; the high-speed shear rate is 15000 rpm, and the shear time is 3 min.

6. The preparation method according to claim 1, characterized in that: In step (3) and step (4), the amount ratio of Pickering emulsion, mesitylene, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-triformaldehydebenzene, chloroform, benzaldehyde and aniline is 2.0 mL: 4.0 mL: 3.5 mg: 1.6 mg: 2.0 mL: 12.1 μL: 10.8 μL; and the standing time at room temperature is 24 h.

7. The preparation method according to claim 1, characterized in that: In step (5), the usage ratio of 3-acrylamidophenylboronic acid, NRG, methanol, polydipentaerythritol pentaacrylate, benzoin dimethyl ether, and MC BTCA-COF@PDA-SH is 38 mg: 29 mg: 20.0 mL: 58 mg: 20 mg: 80 mg.

8. The preparation method according to claim 1, characterized in that: In step (5), the preassembly time is 3.0 h, the ultrasonic treatment time is 10 min, the nitrogen treatment time is 30 min, and the molecular imprinting polymerization is initiated by 365 nm ultraviolet light for 60 min. In the methanol and acetic acid solution, the volume ratio of methanol to acetic acid is 9:

1.

9. A highly active multi-level porous boric acid imprinted hydrogel microsphere adsorbent, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the highly active multi-level porous boric acid imprinted hydrogel microsphere adsorbent MC@PDA-SH@BA-MIPs according to claim 9 for adsorption and separation of flavonoid compound naringin NRG.

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