阅读说明：本技术 一种形状记忆印迹凝胶的制备方法 (Preparation method of shape memory imprinting gel ) 是由 欧红香 李桥 贡晨霞 卫宁 郑旭东 黄如君 于 2019-11-19 设计创作，主要内容包括：本发明公开了一种形状记忆印迹凝胶的制备方法,属吸附材料制备技术领域。采用皮克林乳液法,以纳米二氧化硅为稳定粒子分散液作为水相,以甲基丙烯酸十八酯为油相,利用硼亲和作用,将制备的水溶性苯硼酸作为功能单体与河豚毒素聚合后引入乳液,最后利用紫外光引发聚合得到凝胶,洗脱模板分子后得到形状记忆印迹凝胶。将其应用于水溶液中河豚毒素的吸附分离,制得的形状记忆印迹凝胶具有良好的吸附分离性能,对河豚毒素有着显著的吸附分离效果。制得的印迹凝胶进入水体后能溶胀并与水体充分接触,形成的凝胶结构良好,不易分散,吸附完成后通过烘干能恢复原状,具有一定的形状记忆功能,便于TTX的富集且能重复使用和回收。(The invention discloses a preparation method of shape memory imprinted gel, belonging to the technical field of preparation of adsorption materials. The method comprises the steps of adopting a Pickering emulsion method, taking nano silicon dioxide as a stable particle dispersion liquid as a water phase, taking octadecyl methacrylate as an oil phase, introducing emulsion after polymerizing the prepared water-soluble phenylboronic acid serving as a functional monomer and tetrodotoxin by utilizing boron affinity, finally obtaining gel by utilizing ultraviolet light to initiate polymerization, and obtaining the shape memory imprinted gel after eluting template molecules. The shape memory imprinted gel prepared by applying the method to adsorption separation of tetrodotoxin in aqueous solution has good adsorption separation performance and obvious adsorption separation effect on tetrodotoxin. The prepared imprinted gel can swell after entering a water body and fully contacts with the water body, the formed gel has a good structure and is not easy to disperse, the original shape can be recovered through drying after adsorption is finished, and the imprinted gel has a certain shape memory function, is convenient for enriching TTX and can be repeatedly used and recovered.)

1. The preparation method of the shape memory imprinted gel is characterized by comprising the following steps of:

(1) preparation of phenylboronic acid functional monomer

Adding 3-aminophenylboronic acid into 40mL of 2M NaOH aqueous solution, continuously stirring until no solid particles exist, slowly dropwise adding acryloyl chloride under the condition of ice-water bath, and mechanically stirring for 15min after dropwise adding; then slowly dripping concentrated HCl into the reaction system to adjust the pH value of the system, generating a large amount of white precipitate, filtering the precipitate by using a Buchner funnel, and washing the precipitate by using cold deionized water; dissolving the crude product in deionized water, adding ethanol, and heating to 55-65 deg.C to dissolve soluble substances; filtering out residual insoluble impurities, and crystallizing the filtrate in a refrigerator for 12-16h to obtain a needle-shaped product; after the needle-shaped product is filtered, drying the needle-shaped product in a vacuum drying oven for 2 hours at room temperature; obtaining an acrylamide group phenylboronic acid monomer;

(2) preparation of shape memory blotting gel

Acrylamide group phenylboronic acid monomer is added into 20mL of the solution with the concentration of 40 mu g.L^-1Stirring for 30min, and standing at room temperature for 2-3h to obtain pre-assembled solution; adding nano silicon dioxide with the diameter of 30nm into the pre-assembly solution, and uniformly dispersing the nano silicon dioxide to obtain silicon dioxide dispersion liquid of the pre-assembly solution; sequentially adding N, N-Dimethylacrylamide (DMA) and 2, 2-Diethoxyacetophenone (DEOP) into the preassembly solution dispersion liquid and manually stirring for 1-2min to form a water phase A; shaking the mixed oil phase containing 2-methyl-2-octadecyl acrylate (SMA), ethylene glycol methacrylate (EGDMA), tween 80 and DEOP in ultrasound for 3-10min to obtain oil phase B; then oil phase B is added to water phase A and homogenized at 8000-; injecting the emulsion into a polytetrafluoroethylene mold with the thickness of the outer square and the inner circle of 1.5-2.5mm and the inner diameter of 2-5cm, sealing two sides of the mold by using polyethylene films, and polymerizing for 12-36h under 298-308K ultraviolet light to obtain the shape memory gel polymer.

2. The method for preparing the shape memory imprinted gel according to claim 1, wherein the mass ratio of the 3-aminophenylboronic acid to the acryloyl chloride in the step (1) is 1:1.5-1:2, and the pH value of the system is adjusted to 0.6-2.0 by dropwise adding concentrated HCl.

3. The method for preparing the shape memory imprinted gel according to claim 1, wherein the mass ratio of the crude product in the step (1) to the deionized water and ethanol is 1:20: 1-1: 30: 3.

4. the method for preparing a shape memory imprinted gel according to claim 1, wherein the polymerization mass ratio of the phenylboronic acid monomer and tetrodotoxin (TTX) in the step (2) is 75:1-112.5: 1.

5. The method for preparing shape memory imprinted gel according to claim 1, wherein the SiO of step (2)₂Accounting for 3-6 wt% of the total mass of the water phase.

6. The method for preparing a shape memory imprinting gel according to claim 1, wherein the mass ratio of the N, N-Dimethylacrylamide (DMA) and the 2, 2-Diethoxyacetophenone (DEOP) in the step (2) to the amount of the pre-assembly solution dispersion is 300:1: 2000: 350:1: 1000.

7. The method for preparing shape memory imprinting gel according to claim 1, wherein the components of the oil phase B in step (2) are used in amounts of 6.1-6.9g of octadecyl 2-methyl-2-acrylate (SMA), 0.0260-0.0348g of ethylene glycol methacrylate (EGDMA), 0.6-1.3g of Tween, 0.7-1.3mg of DEOP, and the amount of the phase A and the phase B is such that the ratio of phase B is more than 74% of the total volume of the phases A and B.

8. Use of a shape memory blotting gel prepared according to the method of claim 1 for selective adsorption of tetrodotoxin.

Technical Field

The invention belongs to the technical field of preparation of adsorption materials, and particularly relates to a method for preparing gel with shape memory imprinting by using a Pickering emulsion method.

Background

Shape memory materials (Shape memory materials) refer to materials that are deformed and then restored to their original Shape by physical or chemical stimulation treatment such as heat, light, electricity, etc. Common shape memory materials comprise polyurethane foam and epoxy resin, are usually applied to the field of adsorption separation, and have the advantages of simple separation and adsorption operation, easy recovery, large pore diameter, good dynamic performance and the like. A Flexible Material (FM) refers to a material whose skeleton structure can stretch, bend, twist and remain intact under external stimuli (such as pressure, temperature, guest molecules, etc.). Common flexible materials are polyurethane foam, polypropylene fiber, gel, and the like. The advantage that the flexible material is not easy to damage and can be repeated is favored by the majority of researchers. Among them, the preparation of flexible gel and its adsorption separation application have been widely studied. The preparation of graphene gel for adsorbing and separating heavy metal ions in sewage is taught by the paragraph of great profits. Professor wang seas creatively prepared polyacrylic acid gel by HIPEs and successfully used for the adsorption recovery of copper ions. The general idea of the work is as follows: an oil-in-water high internal phase emulsion system is constructed, a polymerization monomer and a cross-linking agent are added into a water phase, and the flexible columnar polymer is obtained through thermal initiation polymerization. However, this approach has a common drawback that the channels tend to collapse, thereby reducing diffusion efficiency and weakening the separation kinetics.

Tetrodotoxin (TTX) is an amino perhydroquinazoline alkaloid contained in dolphin fish and other organisms. A large number of research results show that the trace TTX preparation can be used as a high-efficiency local anesthesia analgesic clinically, has the effect of remarkably enhancing the effect of resisting arrhythmia and renal failure, and has potential great medicine development value. The globefish yield is high, the slaughter wastewater generated by the globefish flows into the water area, which not only causes environmental damage and certain threat, but also wastes resources due to the discarding of tetrodotoxin. By using the simple and easy separation and extraction method of adsorption, tetrodotoxin can be effectively separated from a complex mixture.

The molecular imprinting technology is a technology for preparing a polymer with specific selectivity for a specific target molecule, namely, Molecular Imprinted Polymers (MIPs), and is widely applied in the aspects of extraction/separation, chemical/biological sensing, artificial antibodies and the like at the present stage, and the introduction of a shape memory gel material into the molecular imprinting technology can effectively perform specific adsorption on the target, so that the adsorption efficiency is higher. However, in the prior art, there is a certain limitation in applying the molecular imprinting technology to adsorption separation, and the preparation method of the molecular imprinting polymer has a certain limitation, so that the types of the functional monomers and the cross-linking agents selected for research are few, and the requirements of practical application cannot be met, and further research on the synthesis of various different types of functional monomers and cross-linking agents is urgently needed.

Disclosure of Invention

The invention aims to provide a preparation method of a shape memory imprinted gel, which is used for improving the adsorption and separation performance of a product. In order to solve the problems, the invention uses nano-silica as stable particles, utilizes the affinity effect of a Pickering high-internal emulsion template method and boron, adopts a self-assembly surface molecular imprinting technology to prepare the imprinted gel polymer with high selectivity, high adsorption capacity, good dynamic performance and shape memory function, and is used for selective recognition and separation of tetrodotoxin in solution.

The technical scheme adopted by the invention is as follows:

the method for preparing the shape memory imprinted gel by stable Pickering emulsion polymerization of the nano-silica nanoparticles comprises the following steps:

(1) preparation of phenylboronic acid functional monomer

Adding 2.59-3.0g of 3-aminophenylboronic acid into 40mL of 2M NaOH aqueous solution, continuously stirring until no solid particles exist, slowly dropwise adding 3.0-3.6mL of acryloyl chloride under the condition of ice-water bath, and mechanically stirring for 15min after dropwise adding; slowly dripping concentrated HCl into the reaction system, adjusting the pH value of the system to about 0.6-2.0, generating a large amount of white precipitate, filtering the precipitate by using a Buchner funnel, and washing the precipitate by using cold deionized water; dissolving the crude product in 60-90mL of deionized water, adding 3-8mL of ethanol, and heating to 55-65 ℃ to dissolve soluble substances; filtering out residual insoluble impurities, and crystallizing the filtrate in a refrigerator for 12-16h to obtain a needle-shaped product; after the needle-shaped product is filtered, drying the needle-shaped product in a vacuum drying oven for 2 hours at room temperature; to obtain the acrylamide group phenylboronic acid monomer.

(2) Preparation of shape memory blotting gel

0.06-0.09g of acrylamide group phenylboronic acid monomer is added into 20mL of the mixture with the concentration of 40 mu g.L^-1Stirring for 30min, and standing at room temperature for 2-3h to obtain pre-assembled solution; adding a proper amount of nano silicon dioxide with the diameter of 30nm into the preassembly solution to uniformly disperse the nano silicon dioxide (SiO)₂3-6 wt% of the total system) to obtain a silica dispersion of a pre-assembled solution; then adding 0.3-0.7g of N, N-Dimethylacrylamide (DMA) and 1.0-2.0mg of 2, 2-Diethoxyacetophenone (DEOP) into the preassembly solution dispersion liquid in sequence and manually stirring for 1-2min to form a water phase A; shaking the mixed oil phase containing 6.1-6.9g 2-methyl-2-propenoic acid octadecyl ester (SMA), 0.0260-0.0348g ethylene glycol methacrylate (EGDMA), 0.6-1.3g Tween 80 and 0.7-1.3mg DEOP in ultrasound for 3-10min to obtain oil phase B; oil phase B was then added to water phase A and homogenized at 8000-20000rpm for 5-8min to form an oil-in-water emulsion; injecting the emulsion into a polytetrafluoroethylene mold with the thickness of the outer square and the inner circle of 1.5-2.5mm and the inner diameter of 2-5cm, sealing two sides of the mold by using polyethylene films, and polymerizing for 12-36h under 298-308K ultraviolet light to obtain the shape memory gel polymer.

(3) Preparation of non-blotting gels

Adding 30nm diameter nanometer silicon dioxide into water to disperse uniformly (SiO)₂3-6 wt% of the total system) to obtain a dispersion; 0.3-0.7g of N, N-Dimethylacrylamide (DMA) and 1-2mg of 2, 2-Diethoxyacetophenone (DEOP) were added to the dispersion in this order and stirred manually for 1-2min to form an aqueous phase A. Mixing oil phase containing 6.1-6.9g octadecyl 2-methyl-2-acrylate (SMA), 0.0260-0.0348g ethylene glycol methacrylate (EGDMA), 0.6-1.3g Tween 80 and 0.7-1.3mg DEOP, and shaking in ultrasound for 3-10min to obtain oil phase B, adding oil phase B into water phase A, and homogenizing at 8000-20000rpm for 5-8min to form oil-in-water emulsion. Injecting the emulsion into a polytetrafluoroethylene mold with the thickness of the outer square and the inner circle of 1.5-2.5mm and the inner diameter of 2-5cm, sealing two sides of the mold by using polyethylene films, and polymerizing for 12-36h under 298-308K ultraviolet light to obtain the non-imprinted gel polymer.

The method for analyzing and testing the adsorption performance in the technical scheme comprises the following steps:

(1) static adsorption test

Adding the shape memory imprinted gel into 10mL of tetrodotoxin solution with a certain concentration, placing the tetrodotoxin solution in a 298K constant-temperature gas bath shaking table for oscillation for a certain time, and investigating the influence of the initial concentration of TTX in the test solution and the change of adsorption time on the TTX adsorption of the imprinted gel; after saturation adsorption, the blotting gel was separated with an inorganic filter, and the concentration of non-adsorbed TTX was measured by high performance liquid chromatography. And calculating the adsorption capacity (Q) from the result_e，mg g^-1)：

Wherein C is₀(mg L^-1) And C_e(mg L^-1) The concentrations of tetrodotoxin before and after adsorption, V (mL) is the volume of the test solution, M (g) is the dosage of the adsorbent, and M is the molecular weight of tetrodotoxin.

(2) Selective adsorption test

Selecting norfloxacin and erythromycin solution as selective adsorption substances to perform a single-component selective adsorption test, respectively preparing template molecules with certain concentration and solutions of the above two antibiotics, respectively taking 10ml of the solutions, respectively adding 0.4g of shape memory imprinted gel and non-imprinted gel adsorbent, standing for a period of time at 25 ℃, and after adsorption is completed, measuring the concentrations of the antibiotics and TTX in the supernatant by using an ultraviolet spectrophotometer and a high performance liquid chromatograph.

Has the advantages that:

the shape memory imprinted gel prepared by utilizing the boron affinity effect of the phenylboronic acid monomer and combining the Pickering emulsion has good adsorption and separation functions and has a remarkable adsorption and separation effect on tetrodotoxin; the obtained product can be dissolved and expanded after entering the water body and fully contacts the water body, the formed gel has a good structure and is not easy to disperse, the original shape can be recovered through drying after the adsorption is finished, and the product has a certain shape memory function, and is convenient for enriching TTX and reusing and recycling the product.

A flexible porous skeleton is constructed by polymerization of an aqueous phase monomer N, N-Dimethylacrylamide (DMA), and a pore structure is effectively supported by polymerization of a small amount of oil-soluble monomer octadecyl methacrylate (SMA) in an inner phase, so that the pore structure of the flexible imprinted polymer is maintained, and the problem of pore collapse of the traditional flexible polymer is solved.

Drawings

FIG. 1 is a H-NMR chart of a water-soluble phenylboronic acid monomer;

FIG. 2 is a FTIR plot of water-soluble phenylboronic acid monomers;

FIG. 3 is an electron micrograph of a imprinted gel at different magnification, wherein a and b are SEM images of the gel at 100 μm, and c and d are SEM images of the surface of the gel at 1 μm;

FIG. 4 is a graph showing the change in size and volume of the imprinted gel adsorbent after standing in a water body for 6 hours;

FIG. 5 shows the isothermal adsorption results of imprinted gels (MIPs) and non-imprinted gels (NIPs) at 298K;

FIG. 6 shows the kinetic adsorption results of imprinted gels (MIPs) and non-imprinted gels (NIPs) at 298K.

Detailed Description

The present invention will be described in detail with reference to specific examples.