阅读说明：本技术 一种环丙沙星选择性分离膜的制备方法及其应用 (Preparation method and application of ciprofloxacin selective separation membrane ) 是由 韩子轩 卢健 秦莹莹 闫永胜 李春香 于 2020-06-16 设计创作，主要内容包括：本发明属功能材料制备技术领域,具体涉及一种环丙沙星选择性分离膜的制备方法及其应用；制备步骤为：将聚偏氟乙烯和β-环糊精相结合,构建兼具有良好柔韧性、抗污性、亲水性、耐用性的柔性基底材料,配合多巴胺自聚合过程在基底外围形成次级改性平台,以环丙沙星为模板分子,基于光引发“巯基-烯”点击化学分子印迹聚合过程,制备得到环丙沙星选择性分离膜；本发明制备的环丙沙星选择性分离膜有效解决了现有环丙沙星选择性分离材料所存在的难回收、易产生二次污染、能耗高等不足,并对环丙沙星具有良好的特异性吸附和分离的能力。(The invention belongs to the technical field of functional material preparation, and particularly relates to a preparation method and application of a ciprofloxacin selective separation membrane; the preparation steps are as follows: the method comprises the following steps of combining polyvinylidene fluoride and beta-cyclodextrin to construct a flexible substrate material with good flexibility, stain resistance, hydrophilicity and durability, forming a secondary modification platform on the periphery of the substrate by matching with a dopamine self-polymerization process, and preparing the ciprofloxacin selective separation membrane by using ciprofloxacin as a template molecule and based on a photoinitiated sulfydryl-alkene click chemical molecular imprinting polymerization process; the ciprofloxacin selective separation membrane prepared by the invention effectively overcomes the defects of difficult recovery, easy generation of secondary pollution, high energy consumption and the like of the existing ciprofloxacin selective separation material, and has good specific adsorption and separation capabilities for ciprofloxacin.)

1. A preparation method of a ciprofloxacin selective separation membrane is characterized by comprising the following steps:

s1, preparation of a hydrophilic base membrane: uniformly mixing polyvinylidene fluoride powder and beta-cyclodextrin powder, adding the mixture into dimethylacetamide, heating and stirring the mixture for a period of time to obtain a casting solution, cooling the casting solution, defoaming the casting solution under a vacuum condition, leveling the defoamed casting solution on a flat plate to form a liquid film with a certain thickness, quickly placing the flat plate in water for phase inversion for a period of time, and drying to obtain a hydrophilic base film;

s2, preparing a modified platform composite membrane: preparing a mixed solution of tris (hydroxymethyl) aminomethane and dopamine, adjusting the pH value of the solution, then immersing the solution into the hydrophilic substrate membrane prepared in S1, slowly stirring the mixture in the air for a period of time, and washing and drying the mixture to obtain a modified platform composite membrane;

s3, preparing a vinyl modified film: preparing a mixed solution of ethanol and water, then immersing the mixed solution into the modified platform composite membrane prepared by S2, adding a certain amount of 3- (methacryloyloxy) propyl trimethoxy silane, heating and refluxing, and then washing and drying by ethanol to obtain a vinyl modified membrane;

s4, preparing the ciprofloxacin selective separation membrane: dissolving ciprofloxacin and trifluoromethyl acrylic acid in acetonitrile, stirring for a period of time to obtain a prepolymerization system, adding dipentaerythritol penta-/hexa-acrylic acid, tetra (3-mercaptopropionic acid) pentaerythritol ester and 2, 2-dimethoxy-2-phenylacetophenone to obtain a mixed solution, finally immersing the vinyl modified membrane prepared by S3 in the mixed solution, discharging oxygen by using nitrogen, sealing, carrying out imprinting polymerization reaction under ultraviolet irradiation, washing with alcohol, washing with water, eluting template molecules by using an eluent, and drying to obtain the ciprofloxacin selective separation membrane.

2. The method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S1, the dosage ratio of polyvinylidene fluoride powder, beta-cyclodextrin powder and dimethylacetamide is 19 g: 1 g: 100 mL.

3. The method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S1, in step S1, the heating time is 24h, and the heating temperature is 50 ℃; the defoaming treatment time is 30 min; the thickness of the liquid film is 100-400 mu m; the phase inversion time is 30-360 min.

4. The method of claim 1, wherein in step S2, the ratio of the amounts of tris (hydroxymethyl) aminomethane, dopamine and water is 1 mmol: 1 mmol: 100 mL.

5. The method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S2, the pH value of the solution is 8.5, and the stirring time is 1-12 h.

6. The method of claim 1, wherein in step S3, the volume ratio of ethanol to water to 3- (methacryloyloxy) propyltrimethoxysilane in the mixed solution is 80: 20: 3.

7. the method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S3, in step S3, the heating reflux temperature is 80 ℃; the heating reflux time is 12 h.

8. A method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S4, the ratio of the amounts of ciprofloxacin, trifluoromethyl acrylic acid and acetonitrile is 0.1 mmol: 0.6 mmol: 60 mL; the dosage ratio of the trifluoromethyl acrylic acid, the dipentaerythritol penta-/hexa-acrylic acid, the tetra (3-mercaptopropionic acid) pentaerythritol ester and the 2, 2-dimethoxy-2-phenylacetophenone is 0.6 mmol: 0.6 mL: 0.2 mL: 20 mg.

9. The method for preparing a ciprofloxacin selective separation membrane according to claim 1, wherein in step S4, the prepolymerization is stirred for a period of 2 h; the time of the imprinting polymerization reaction is 1-4 h.

10. The membrane material prepared by the method according to any one of claims 1 to 9 is applied to selective recognition and separation of ciprofloxacin in a mixed solution of ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin.

Technical Field

The invention belongs to the technical field of functional material preparation, and particularly relates to a preparation method and application of a ciprofloxacin selective separation membrane.

Background

The method has the advantages that the method has a vital role in maintaining human life and sustainable development of society, and is an important resource on which earth life depends. However, with the rapid growth of the population and the rapid development of society, the water pollution situation is becoming more serious, and the antibiotic pollution has attracted more attention in recent years. Among common antibiotics, ciprofloxacin has the characteristics of long half-life and high chemical stability, and particularly has non-biodegradability, so that the ciprofloxacin is difficult to effectively remove by the traditional water treatment process. Under such circumstances, it is urgent to develop a method capable of effectively removing ciprofloxacin in an environmental water body. Common antibiotic pollution treatment methods mainly comprise a chemical precipitation method, an electrolysis method, an adsorption method, a membrane separation method, a distillation method, an extraction method, a biodegradation method and the like. Wherein, the precipitation method, the electrolysis method, the adsorption method and the like are easy to generate secondary pollution; distillation, extraction and biodegradation processes are complicated to operate and have high operating costs. In contrast, the membrane separation method has the advantages of low energy consumption, simple operation, no phase change, convenient material recovery, no secondary pollution, high separation efficiency and the like, thereby being an ideal method for treating the ciprofloxacin pollution in water.

Considering that a large amount of good carbon sources needing to be reserved are contained in the water body, the ciprofloxacin has potential recycling value, and the concentration of the target object is often lower than that of a non-target object, the method has important social and scientific significance for the research on the single selective separation of the ciprofloxacin in the water. The molecularly imprinted membrane is a material with high-efficiency molecular selectivity developed by combining a membrane separation technology and a molecularly imprinted technology in recent years. The method takes a porous filter membrane as a carrier, combines a molecular selective recognition site constructed on the surface and in a pore passage by a molecular imprinting technology, and utilizes the characteristic that the molecular selective recognition site allows one part of substances to pass and prevents the other part of substances from passing to realize the efficient separation, enrichment or purification of target molecules in a solution by selective recognition and adsorption of specific molecules.

Although the work of realizing selective separation of antibiotics based on the molecularly imprinted membrane has been reported, due to the lack of optimization of the imprinting strategy and the lack of compatibility of the imprinting recognition sites and the membrane material, the selective separation performance of the obtained material still needs to be enhanced. Based on this, a proper imprinting strategy needs to be designed according to the characteristics and the existing environment of the target object, and a molecularly imprinted membrane with good compatibility is constructed, so that the separation performance of the molecularly imprinted membrane is effectively improved, and the potential comprehensive characteristics of the molecularly imprinted membrane are exerted to the maximum extent.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to overcome the technical defects in the prior art, make up the defect of poor compatibility between the imprinting recognition site and the membrane material of the existing molecularly imprinted membrane, and enable the molecularly imprinted membrane to exert the comprehensive performance to the maximum extent while ensuring high selectivity and high adsorption capacity on target molecules (ciprofloxacin).

The present invention achieves the above-described object by the following technical means.

A preparation method of a ciprofloxacin selective separation membrane comprises the following steps:

s1, preparation of a hydrophilic base membrane: uniformly mixing polyvinylidene fluoride powder and beta-cyclodextrin powder, adding the mixture into dimethylacetamide, heating and stirring the mixture for a period of time to obtain a casting solution, cooling the casting solution, defoaming the casting solution under a vacuum condition, leveling the defoamed casting solution on a flat plate to form a liquid film with a certain thickness, immediately placing the flat plate in water for phase inversion for a period of time, and drying to obtain a hydrophilic base film;

s2, preparing a modified platform composite membrane: preparing a mixed solution of tris (hydroxymethyl) aminomethane and dopamine, adjusting the pH value of the solution, then immersing the solution into the hydrophilic substrate membrane prepared in S1, slowly stirring the mixture in the air for a period of time, and washing and drying the mixture to obtain a modified platform composite membrane;

s3, preparing a vinyl modified film: preparing a mixed solution of ethanol and water, then immersing the mixed solution into the modified platform composite membrane prepared by S2, adding a certain amount of 3- (methacryloyloxy) propyl trimethoxy silane, heating and refluxing, and then washing and drying by ethanol to obtain a vinyl modified membrane;

s4, preparing the ciprofloxacin selective separation membrane: dissolving ciprofloxacin and trifluoromethyl acrylic acid in acetonitrile, stirring for a period of time to obtain a prepolymerization system, adding dipentaerythritol penta-/hexa-acrylic acid, tetra (3-mercaptopropionic acid) pentaerythritol ester and 2, 2-dimethoxy-2-phenylacetophenone to obtain a mixed solution, finally immersing the vinyl modified membrane prepared by S3 in the mixed solution, discharging oxygen by using nitrogen, sealing, carrying out imprinting polymerization reaction under ultraviolet irradiation, washing with alcohol, washing with water, eluting template molecules by using an eluent, and drying to obtain the ciprofloxacin selective separation membrane.

Preferably, in step S1, the usage ratio of the polyvinylidene fluoride powder, the beta-cyclodextrin powder and the dimethylacetamide is 19 g: 1 g: 100 mL.

Preferably, in step S1, the heating time is 24h, and the heating temperature is 50 ℃.

Preferably, in step S1, the defoaming treatment time is 30 min.

Preferably, in step S1, the liquid film has a thickness of 100 to 400 μm.

Preferably, in step S1, the phase inversion time is 30-360 min.

Preferably, in step S2, the ratio of the tris (hydroxymethyl) aminomethane to the dopamine to the water is 1 mmol: 1 mmol: 100 mL.

Preferably, in step S2, the pH of the solution is 8.5, and the stirring time is 1 to 12 hours.

Preferably, in step S3, the volume ratio of ethanol, water and 3- (methacryloyloxy) propyltrimethoxysilane in the mixed solution is 80: 20: 3.

preferably, in step S3, the heating reflux temperature is 80 ℃; the heating reflux time is 12 h.

Preferably, in step S4, the ratio of the ciprofloxacin, the trifluoromethyl acrylic acid and the acetonitrile is 0.1 mmol: 0.6 mmol: 60 mL.

Preferably, in step S4, the prepolymerization is stirred for a period of 2 h; the time of the imprinting polymerization reaction is 1-4 h.

Preferably, in step S4, the ratio of the amounts of the trifluoromethyl acrylic acid, the dipentaerythritol penta-/hexa-acrylic acid, the tetra (3-mercaptopropionic acid) pentaerythritol ester and the 2, 2-dimethoxy-2-phenylacetophenone is 0.6 mmol: 0.6 mL: 0.2 mL: 20 mg.

Preferably, in step S4, the wavelength of the ultraviolet light is 365 nm; the time of the imprinting polymerization reaction is 1-4 h.

Preferably, in step S4, the sealing method is to seal with a vacuum plug, a degreasing tape and a preservative film; the eluent is a mixed solution of methanol and acetic acid, and the volume ratio of the methanol to the acetic acid is 95: 5; the elution mode is that oscillation is carried out at room temperature, and ciprofloxacin can not be detected in eluent.

The polyvinylidene fluoride powder in the technical scheme is used as a film making material.

The beta-cyclodextrin powder in the technical scheme is used as a basement membrane hydrophilic modification material.

The dimethylacetamide in the technical scheme is used as a casting solution solvent.

The tris (hydroxymethyl) aminomethane in the technical scheme has the function of dopamine autopolymerization buffer solution.

The dopamine in the technical scheme is used as a modified platform construction material.

The 3- (methacryloyloxy) propyl trimethoxysilane in the technical scheme is used as a film surface vinyl modification reagent.

The ethanol in the technical scheme is used as a solvent.

The ciprofloxacin in the technical scheme is used as a template molecule.

The trifluoromethyl acrylic acid in the technical scheme is used as a functional monomer.

The acetonitrile in the technical scheme is used as a molecular imprinting polymerization solvent.

The pentaerythritol tetrakis (3-mercaptopropionate) described in the above technical scheme acts as a cross-linking agent.

The dipentaerythritol penta-/hexa-acrylic acid in the technical scheme is used as an auxiliary crosslinking agent.

The 2, 2-dimethoxy-2-phenylacetophenone in the technical scheme has the function of an initiator.

The invention also comprises the application of the ciprofloxacin selective separation membrane in selective adsorption and separation of ciprofloxacin in the ciprofloxacin-containing mixed solution, in particular to the selective adsorption and separation of ciprofloxacin in the mixed solution of ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin.

And (3) testing the material performance:

(1) selective adsorption experiment

Weighing 8 parts of ciprofloxacin selective separation membrane, respectively placing the ciprofloxacin selective separation membrane into test tubes, respectively adding 10mL of mixed solution of ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin with the concentration of 5, 10, 25, 50, 75, 100, 150 and 200mg/L, standing and adsorbing for 180min at room temperature, measuring the concentration of the unadsorbed ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin in the solution by an ultraviolet-visible spectrophotometer after adsorption is finished, and calculating the adsorption quantity (Q, mg/g) according to the result:

Q＝(C₀-C_e)×V/m (1)

wherein C is₀(mg/L) and C_e(mg/L) are adsorption respectivelyConcentration of the same molecule in the previous and subsequent solutions, V (mL) is the volume of the adsorption solution, and m (g) is the mass of the ciprofloxacin-selective separation membrane added.

(2) Permselectivity experiments

The prepared ciprofloxacin selective separation membrane is arranged in the center of a static penetration device, the device is divided into two cavities which are completely the same by the prepared ciprofloxacin selective separation membrane, 100mL of mixed solution of ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin with the concentration of 100mg/L is added into one cavity, 100mL of water is added into the other cavity, 5mL of solution (penetrating fluid) is respectively taken from a pure solvent cavity at the time of 5 min, 10 min, 15 min, 30min, 60min, 90 min, 120 min and 180min, 5mL of water is immediately backfilled to ensure that the two cavities of solution have no height difference, and the concentrations of ciprofloxacin, enrofloxacin, norfloxacin and ofloxacin in the sampling penetrating fluid are measured by an ultraviolet-visible spectrophotometer.

The invention has the advantages and technical effects that:

(1) compared with the existing ciprofloxacin selective separation material, the ciprofloxacin selective separation membrane prepared by the invention has the advantages of high separation efficiency, strong selectivity, easy recovery of materials, no need of phase change in the separation process and the like, and effectively solves the defects of difficult recovery, easy generation of secondary pollution, high energy consumption and the like of the existing ciprofloxacin selective separation material.

(2) Compared with the traditional molecularly imprinted membrane, the invention combines polyvinylidene fluoride and beta-cyclodextrin to construct a flexible substrate material with good flexibility, stain resistance, hydrophilicity and durability; forming a secondary modified platform at the periphery of the substrate in cooperation with a dopamine self-polymerization process, and constructing a macroscopic core-shell type modified platform composite membrane; on the basis, the ciprofloxacin selective separation membrane is obtained based on a photoinitiated sulfydryl-alkene click chemical molecular imprinting polymerization process. The construction strategy of the invention ensures the high selectivity of the obtained separation material, and greatly improves the overall comprehensive performance of the material, so that the material is more suitable for the application conditions required by the selective separation of ciprofloxacin.

Drawings

FIG. 1 is a selective permeation curve of the ciprofloxacin selective separation membrane in example 1.

The selective permeation curve of the ciprofloxacin selective separation membrane in example 2 in fig. 2.

The selective permeation curve of the ciprofloxacin selective separation membrane in example 3 in fig. 3.

Detailed Description

The invention is further described with reference to the drawings and the detailed description.