Preparation method and application of boron affinity surface imprinted adsorbent based on attapulgite

Abstract

The present invention belongs to the field of functional material preparation and discloses a method for preparing a nystatin adsorbent based on attapulgite. The specific preparation steps are: (1) pretreating the attapulgite; (2) coating the surface of the pretreated attapulgite with a layer of dopamine; (3) modifying the dopamine with a layer of bromine initiator; (4) preparing a surface-imprinted adsorption material with boron affinity by free radical polymerization; and (5) conducting a nystatin adsorption test on the material. The adsorption separation material obtained by this preparation method has excellent mass transfer kinetics and adsorption efficiency, is low in cost, is simple to prepare, has a specific adsorption effect on nystatin, and can be used to purify crude nystatin.

Description

Technical Field

[0001] The invention relates to a method for preparing an attapulgite surface imprinted adsorbent, and in particular to a method for preparing a molecularly imprinted adsorption material used for separation and purification of nystatin. Background Art

[0002] Attapulgite, also known as ATP, is a hydrous magnesium aluminum silicate mineral with a layered chain transition structure. Its theoretical chemical formula is Si8Mg5O 20 (OH)2(OH2)4·4H2O is a rare non-metallic mineral raw material. Its crystals are rod-shaped or fibrous, with both silicon-oxygen tetrahedrons and longitudinal side chains in the crystal structure. Each chain unit is connected by Si-O-Si bonds, forming zeolite-like channels with a cross-sectional size of 0.37nm × 0.64nm. Attapulgite, due to its rod-shaped crystal morphology, unique pore structure, and large specific surface area, has excellent adsorption, purification, and decolorization properties, making it widely used in the chemical industry, environmental protection, agriculture, metallurgy, and other fields. Attapulgite is inexpensive, has a large specific surface area, and is rich in surface silanol groups, making it an excellent adsorbent and adsorbent carrier. Furthermore, studies have revealed that charge imbalance exists on the surface of attapulgite, which improves its adsorption properties.

[0003] Molecular imprinting technology is one of the primary approaches currently used to develop highly selective materials. Its principle is to mimic the natural antigen-antibody reaction mechanism by introducing molecular recognition sites into polymer materials, thereby creating polymer compounds that spatially and spatially match specific target molecules and exhibit a specific, predetermined selectivity. During the preparation process, a template molecule and a functional monomer form a prepolymer through covalent, non-covalent, or metal-metal interactions. The functional monomer then polymerizes under the action of a crosslinker, anchoring the template molecule within the polymer. Finally, removal of the template molecule leaves behind a cavity in the polymer that is complementary to the template molecule in size, shape, and orientation of its functional groups. This cavity not only preserves the ordered arrangement of functional groups that complement the template molecule's chemical structure but also maintains its overall spatial conformation, enabling specific binding upon the next encounter with the template molecule. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a molecular imprinting adsorption separation material using attapulgite as a carrier, and to apply the material to the separation and purification of nystatin.

[0005] The technical solution adopted by the present invention is: a preparation method and application of a boron affinity surface imprinted adsorbent based on attapulgite, and the specific solution includes:

[0006] (1) Ultrasonic dispersion of attapulgite in hydrochloric acid solution, then adding surfactant, stirring and soaking at room temperature for 20 h, and filtering;

[0007] (2) calcining the filtered attapulgite under vacuum conditions to obtain activated attapulgite;

[0008] (3) The activated attapulgite was dispersed in a Tris-HCl (1.5 M, pH 8.8) buffer solution, and dopamine hydrochloride was added to initiate the dopamine self-polymerization reaction. After the reaction, the attapulgite was washed with ethanol and water, and finally dried in a vacuum oven at 50°C to obtain attapulgite coated with dopamine.

[0009] (4) dispersing the dopamine-coated attapulgite in an organic solvent, adding BIBB and triethylamine, stirring and reacting, washing with ethanol and water after the reaction, and finally drying in a vacuum oven at 50° C. to obtain surface-modified attapulgite;

[0010] (5) adding an organic solvent, surface-modified attapulgite, nystatin template molecules, and functional monomers into a reactor for pre-assembly, and then adding a crosslinker EGDMA and an initiator to initiate free radical polymerization on the surface of the attapulgite at 50°C;

[0011] (6) The reaction solution was filtered, and the template molecules were eluted with methanol: water = 3:1, and then washed with water, and dried in a vacuum oven at 50°C to obtain a attapulgite-based surface imprinted adsorbent with boron affinity;

[0012] (7) The nystatin sample was prepared into a solution, an adsorbent was added, and the adsorption of the adsorbent was tested by ultraviolet spectroscopy.

[0013] The present invention has the following characteristics:

[0014] (1) Attapulgite is used as the carrier of the adsorbent. Attapulgite has the advantages of low price, uniform pore size, and large relative area. At the same time, a special pretreatment method is used to match the pore size with the molecular size of nystatin, which helps to increase the mass transfer rate and adsorption capacity of nystatin.

[0015] (2) Using molecularly imprinted polymers as adsorbents for nystatin, the recognition sites formed in the molecularly imprinted polymers and the template molecules have a specific matching relationship similar to that between a key and a lock. This matching relationship has strong specificity and good selectivity, resulting in excellent separation effects.

[0016] (3) Using a benzene triboronic acid derivative with an alkenyl group and three boronic acid groups on the benzene ring as a functional monomer, the direction of interaction with nystatin can be precisely adjusted by the boronic acid at different positions, thereby greatly increasing the adsorption selectivity for nystatin. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a flow chart for the preparation of the attapulgite-based molecularly imprinted adsorption material of the present invention.

[0018] Figure 2 Schematic diagram of the interaction between the adsorbent and nystatin in the present invention. DETAILED DESCRIPTION

[0019] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0020] Example 1

[0021] (1) Add 10 g of attapulgite and 500 mL of 10% hydrochloric acid to a round-bottom flask, disperse by ultrasonication for 10 min, then add 500 mg of stearyl polyoxyethylene (2) ether, stir and soak for 20 h, and filter.

[0022] (2) The filtered attapulgite was calcined at a vacuum of 50 mmHg for 4 h, with the temperature controlled at about 300°C.

[0023] (3) 1 g of activated attapulgite and 30 mL of Tris-HCl (1.5 M, pH 8.8) buffer solution were added to the reactor and ultrasonically dispersed for 10 min. Then, 5 g of dopamine hydrochloride was added to initiate the dopamine self-polymerization reaction. After the reaction, the mixture was washed with ethanol and water and finally dried in a vacuum oven at 50°C to obtain attapulgite coated with dopamine.

[0024] (4) Add the dopamine-coated attapulgite and 30 mL of tetrahydrofuran into the reactor, ultrasonically disperse for 10 min, then add 0.5 mL of BIBB and 1 mL of triethylamine, and stir at room temperature for 2 h. After the reaction, wash with ethanol and water, and finally dry in a vacuum oven at 50 °C to obtain surface-modified attapulgite.

[0025] (5) 1 g of bromine-attached attapulgite and 20 mL of methanol were added to the reactor and ultrasonically dispersed for 10 min. Then, 1 mmol of nystatin template molecule and 5 mmol of functional monomer 5-alkenyl-1,2,3-benzenetriboric acid were added for pre-assembly. Then, 10 mmol of cross-linker EGDMA and 0.5 mmol of initiator BPO were added to initiate free radical polymerization on the attapulgite surface at 50 °C.

[0026] (6) The reaction solution was filtered, and the template molecules were eluted with methanol: water = 3:1 as an eluent, and then washed with water. After drying in a vacuum oven at 50°C, a attapulgite-based surface imprinted adsorbent with boron affinity was obtained.

[0027] (7) A 0.5 mmol nystatin sample was dissolved in 20 mL DMF to prepare a solution, 1 g of adsorbent was added, and the solution was stirred and adsorbed for 1 h. After filtration, the adsorption efficiency of the adsorbent was tested by UV spectroscopy.

[0028] Example 2

[0029] (1) Add 10 g of attapulgite and 350 mL of 20% hydrochloric acid to a round-bottom flask, disperse by ultrasonication for 10 min, then add 300 mg of oleyl polyoxyethylene (10) ether, stir and soak for 20 h, and filter.

[0030] (2) The filtered attapulgite was calcined at a vacuum of 30 mmHg for 4 h, with the temperature controlled at about 400°C.

[0031] (3) 1 g of activated attapulgite and 30 mL of Tris-HCl (1.5 M, pH 8.8) buffer solution were added to the reactor and ultrasonically dispersed for 10 min. Then, 5 g of dopamine hydrochloride was added to initiate the dopamine self-polymerization reaction. After the reaction, the mixture was washed with ethanol and water and finally dried in a vacuum oven at 50°C to obtain attapulgite coated with dopamine.

[0032] (4) Add the dopamine-coated attapulgite and 30 mL of dichloromethane into the reactor and ultrasonically disperse for 10 min. Then, add 0.5 mL of BIBB and 1 mL of triethylamine and stir at room temperature for 2 h. After the reaction, wash with ethanol and water, and finally dry in a vacuum oven at 50 °C to obtain surface-modified attapulgite.

[0033] (5) 1 g of bromine-attached attapulgite and 20 mL of acetone were added to the reactor and ultrasonically dispersed for 10 min. Then, 1 mmol of nystatin template molecule and 5 mmol of functional monomer 6-alkenyl-1,2,4-benzenetriboric acid were added for pre-assembly. Then, 10 mmol of cross-linker EGDMA and 0.5 mmol of initiator AIBN were added to initiate free radical polymerization on the attapulgite surface at 50 °C.

[0034] (6) The reaction solution was filtered, and the template molecules were eluted with methanol: water = 3:1 as an eluent, and then washed with water. After drying in a vacuum oven at 50°C, a attapulgite-based surface imprinted adsorbent with boron affinity was obtained.

[0035] (7) 0.5 mmol of nystatin sample was dissolved in 20 mL of DMSO to prepare a solution, 1 g of adsorbent was added, and the solution was stirred and adsorbed for 1 h. After filtration, the adsorption efficiency of the adsorbent was tested by ultraviolet spectroscopy.

[0036] Example 3

[0037] (1) Add 10 g of attapulgite and 200 mL of 30% hydrochloric acid to a round-bottom flask, disperse by ultrasonication for 10 min, then add 100 mg of cetyl polyoxyethylene (20) ether, stir and soak for 20 h, and filter.

[0038] (2) The filtered attapulgite was calcined at a vacuum of 10 mmHg for 4 h at a temperature of about 500°C.

[0039] (3) 1 g of activated attapulgite and 30 mL of Tris-HCl (1.5 M, pH 8.8) buffer solution were added to the reactor and ultrasonically dispersed for 10 min. Then, 5 g of dopamine hydrochloride was added to initiate the dopamine self-polymerization reaction. After the reaction, the mixture was washed with ethanol and water and finally dried in a vacuum oven at 50°C to obtain attapulgite coated with dopamine.

[0040] (4) Add the dopamine-coated attapulgite and 30 mL of cyclohexane into the reactor and ultrasonically disperse for 10 min. Then, add 0.5 mL of BIBB and 1 mL of triethylamine and stir at room temperature for 2 h. After the reaction, wash with ethanol and water, and finally dry in a vacuum oven at 50 °C to obtain surface-modified attapulgite.

[0041] (5) 1 g of bromine-attached attapulgite and 20 mL of acetonitrile were added to the reactor and ultrasonically dispersed for 10 min. Then, 1 mmol of nystatin template molecule and 5 mmol of functional monomer 6-alkenyl-1,3,5-benzenetriboric acid were added for pre-assembly. Then, 10 mmol of cross-linker EGDMA and 0.5 mmol of initiator BPB were added to initiate free radical polymerization on the attapulgite surface at 50 °C.

[0042] (6) The reaction solution was filtered, and the template molecules were eluted with methanol: water = 3:1 as an eluent, and then washed with water. After drying in a vacuum oven at 50°C, a attapulgite-based surface imprinted adsorbent with boron affinity was obtained.

[0043] (7) 0.5 mmol of nystatin sample was dissolved in 20 mL of methanol to prepare a solution, 1 g of adsorbent was added, and the solution was stirred and adsorbed for 1 h. After filtration, the adsorption efficiency of the adsorbent was tested by ultraviolet spectroscopy.

Claims

1. A method for preparing a nystatin molecularly imprinted adsorbent, characterized in that: include: (1) Ultrasonic dispersion of attapulgite in hydrochloric acid solution, then adding surfactant, stirring and soaking for 20 h, and filtering; (2) calcining the filtered attapulgite under vacuum conditions to obtain activated attapulgite; (3) dispersing the activated attapulgite in a Tris-HCl buffer solution, adding dopamine hydrochloride to initiate dopamine self-polymerization, washing with ethanol and water after the reaction, and finally drying in a vacuum oven to obtain attapulgite coated with dopamine; (4) dispersing the dopamine-coated attapulgite in an organic solvent, adding 2-bromoisobutyryl bromide (BIBB) and triethylamine, stirring and reacting, washing with ethanol and water after the reaction, and finally drying in a vacuum oven to obtain surface-modified attapulgite; (5) An organic solvent, surface-modified attapulgite, a nystatin template molecule, and a functional monomer are added to a reactor for pre-assembly. Then, a crosslinker, ethylene glycol dimethyl ether acrylate (EGDMA), and an initiator are added to initiate free radical polymerization on the surface of the attapulgite under heating conditions. The functional monomer is benzenetriboric acid containing an alkenyl group on the benzene ring, and its structural formula is as follows: ； (6) filtering the reaction solution, eluting the template molecules with an eluent, washing with water, and drying in a vacuum oven to obtain a attapulgite-based surface imprinted adsorbent with boron affinity; (7) The nystatin sample was prepared into a solution, an adsorbent was added, and the adsorption of the adsorbent was tested by ultraviolet spectroscopy.

2. The preparation method according to claim 1, characterized in that In step (1), the concentration of the hydrochloric acid solution is 10-30%.

3. The preparation method according to claim 1, characterized in that In step (1), the surfactant includes one of stearyl polyoxyethylene (2) ether, stearyl polyoxyethylene (10) ether, stearyl polyoxyethylene (20) ether, stearyl polyoxyethylene (21) ether, oleyl polyoxyethylene (2) ether, oleyl polyoxyethylene (10) ether, oleyl polyoxyethylene (20) ether, cetyl polyoxyethylene (2) ether, cetyl polyoxyethylene (10) ether, cetyl polyoxyethylene (20) ether, lauryl polyoxyethylene (4) ether, and lauryl polyoxyethylene (23) ether.

4. The preparation method according to claim 1, characterized in that In step (2), the vacuum degree is 10-50 mmHg.

5. The preparation method according to claim 1, characterized in that In step (2), the calcination temperature is 300-500°C.

6. The preparation method according to claim 1, characterized in that In step (4), the organic solvent is one or two of acetonitrile, tetrahydrofuran, methyl tert-butyl ether, dichloromethane, n-hexane, and cyclohexane.

7. The preparation method according to claim 1, characterized in that In step (5), the organic solvent is one or two of methanol, ethanol, propanol, butanol, isopropanol, acetonitrile, and acetone.

8. The preparation method according to claim 1, characterized in that In step (5), the free radical polymerization initiator is one of benzoyl peroxide (BPO), diisopropyl peroxide (DIBP), tert-butyl peroxide (TBP), azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), and tert-butyl perbenzoate (BPB).

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