CN107441848B

CN107441848B - A kind of silk fibroin nanofiltration membrane with micro-nano structure on the surface, preparation method and application thereof

Info

Publication number: CN107441848B
Application number: CN201710671426.3A
Authority: CN
Inventors: 张玲; 李春忠; 高小超; 苟静
Original assignee: East China University of Science and Technology
Current assignee: East China University of Science and Technology
Priority date: 2017-08-08
Filing date: 2017-08-08
Publication date: 2020-04-03
Anticipated expiration: 2037-08-08
Also published as: CN107441848A

Abstract

The invention discloses a silk fibroin nanofiltration membrane with a micro-nano structure on the surface, a preparation method and an application thereof. The specific operation steps are as follows: degumming, dissolving, dialysis, filtering, centrifuging and concentrating silk fibroin to obtain silk fibroin. The protein solution and the polymer solution are mixed uniformly, and a silk fibroin nanofiber filter membrane with a micro-nano structure on the surface is prepared after electrospinning and post-processing. The diameter of the nanofibers is 100–1000nm, the thickness of the membrane is 2-10um, the porosity of the fiber membrane is 60–85%, and the pore size is 20–500nm. The filtration efficiency of PM2.5 and PM10 can reach more than 99%. The process of the invention is simple, the process is non-toxic and environmentally friendly, and has broad application prospects in the field of personal and industrial air filtration equipment.

Description

Silk fibroin nanofiltration membrane with micro-nano structure on surface, preparation method and application thereof

Technical Field

The invention belongs to the technical field of preparation of filter materials, and particularly relates to a silk fibroin nanofiltration membrane with a micro-nano structure on the surface, a preparation method and application thereof.

Background

In recent years, with the development of urban industry, the problem of air pollution is becoming more serious, and the problem is becoming one of the most serious environmental problems in society. As the main cause of severe haze weather, PM2.5 refers to ultrafine particles with a particle size of less than 2.5 microns, has a large specific surface area, is easy to adsorb a large amount of toxic and harmful substances, can enter a respiratory system through alveolus, and improves the incidence rate of cardiovascular diseases and respiratory system diseases. To some extent, urban life is moving away from the health goals pursued by people. Traditional gauze mask filter material can have higher filtration efficiency to the granule more than the micron order, but is difficult to realize the effective filtration to submicron order granule, can't effectively protect to the haze. The electrostatic spinning nanofiber membrane has the characteristics of controllable structure, small fiber diameter, small pore diameter, high porosity and the like, and has excellent barrier property, so that the electrostatic spinning nanofiber membrane can be used as a high-performance filter material and has wide application prospect. In recent years, researches on electrostatic spinning in the field of filter materials are gradually increased, and a method (CN 104711771A) for preparing a nanofiber membrane by electrostatic spinning, a single-layer supporting multifunctional air filter membrane (CN 105833744A), a high-efficiency low-resistance composite fiber PM2.5 filter membrane and an electrostatic spinning preparation method (CN104436865A) are disclosed, a novel screen window (CN 204782666U) capable of filtering and removing PM2.5, preparation of a nanofiber porous membrane and application thereof in air filtration (thesis), preparation of a high-efficiency low-resistance PAN electrostatic spinning micro-nano filter membrane and performance research (thesis) and the like are disclosed. Therefore, the existing air filter material is mainly prepared by polymerizing polyacrylonitrile, polyimide and the like through electrostatic spinning, and generally has the problems of low filter efficiency, large air resistance and poor comprehensive filter performance, so that a novel high-performance air filter material needs to be developed.

Disclosure of Invention

In order to solve the technical problems, one of the objectives of the present invention is to provide a silk fibroin nanofiltration membrane with a micro-nano structure on the surface; the parameters of the filter membrane are as follows: the diameter of the fiber is 100-1000 nm, the thickness of the membrane is 2-10um, the porosity of the fiber membrane is 60-85%, and the pore size is 20-500 nm.

The invention also aims to provide a preparation method of the silk fibroin nanofiltration membrane with the surface having the micro-nano structure, which comprises the following specific operation steps:

(1) preparing a silk fibroin solution: degumming silk by using a sodium carbonate aqueous solution to obtain degummed silk, dissolving the degummed silk in a lithium bromide solution to obtain a silk fibroin-lithium bromide solution, dialyzing, filtering, centrifuging and concentrating the silk fibroin-lithium bromide solution to obtain the silk fibroin solution with the mass percentage of 5-20;

(2) preparation of the polymer solution: dissolving a polymer in deionized water, and fully stirring at room temperature until the polymer is completely dissolved to obtain a polymer solution with the mass percentage of 2-10%;

(3) preparing a silk fibroin and polymer mixed electrostatic spinning solution: blending silk fibroin solution and polymer solution, fully and uniformly stirring at room temperature to obtain blended electrostatic spinning solution, wherein the concentration of the formed uniform and stable mixed spinning solution is 5-15%;

(4) preparing a nanofiber filtering membrane through electrostatic spinning: and (3) carrying out electrostatic spinning on the spinning solution to obtain the nanofiber filtering membrane.

(5) And (3) post-treatment of a nanofiber filtering membrane: soaking the prepared nanofiber filter membrane in ethanol for 10-20 minutes to complete phase transformation, so that the nanofiber filter membrane is insoluble in water. And soaking the filtering membrane in deionized water to dissolve and etch the polymer phase, and finally obtaining the silk fibroin nanofiber filtering membrane with the surface having the micro-nano structure.

As a preferred technical scheme of the invention:

the mass percent of the sodium carbonate aqueous solution in the step (1) is 0.5-1%, the degumming time is 30-60 minutes, and the molar concentration of the lithium bromide aqueous solution is 8.5-9.5M.

The polymer in the step (2) comprises one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol and polyacrylamide.

The mass ratio of the silk fibroin solution to the polymer solution in the step (3) is (1: 1) - (6: 1).

The electrostatic spinning process parameters in the step (4) are as follows: spinning voltage is 7-20kV, receiving distance is 15-30cm, flow rate of spinning solution is 0.1-2.0ml/h, ambient temperature is 25-30 ℃, ambient relative humidity is 25-55%, and spinning time is 10-30 minutes.

In the step (5), the concentration of the ethanol is 80-100%, and the soaking and etching time is 12-36 hours.

The nanofiber filtering membrane can be applied to preparation of civil or industrial air filtering equipment, including masks, air conditioners, air purifiers and filter elements thereof.

Has the advantages that:

1. the raw material of the invention is silk fibroin, the whole preparation process does not involve any substances which are not friendly to the environment and human beings, and simultaneously the product can be biodegraded, thus being a pure green production process.

2. The surface of the silk fibroin nanofiber membrane prepared by the method has rich micro-nano structures, large specific surface area and strong adsorption force, and the characteristic structure of the material enables the silk fibroin nanofiber membrane to have high filtering efficiency and low air resistance.

3. The silk fibroin nano-filtration membrane with the micro-nano structure on the surface prepared by the invention has the filtration efficiency of more than 99 percent on PM2.5 and PM10, and the comprehensive filtration performance of the silk fibroin nano-filtration membrane is superior to that of the existing nano-fiber filtration material.

4. The preparation method provided by the invention can be used for production on a conventional electrostatic spinning machine, and has the advantages of simple process and wide application range.

Drawings

Fig. 1 is a scanning electron microscope photograph of the silk fibroin nanofiltration membrane with the micro-nano structure on the surface prepared in example 1;

fig. 2 is a scanning electron microscope photograph of the silk fibroin nanofiltration membrane with the micro-nano structure on the surface prepared in example 2.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

(1) Firstly, putting natural domestic silkworm silk into a boiled sodium carbonate solution with the mass percentage of 0.5%, degumming for 30 minutes, removing surface sericin, cleaning to obtain silk fibroin, and placing the silk fibroin in a vacuum oven at the temperature of 30 ℃ for vacuum drying for 2 days; dissolving degummed fibroin in 9.5M lithium bromide aqueous solution at 60 ℃, dissolving for 3 hours, filtering, placing the fibroin solution in a dialysis box, sealing, soaking in deionized water for dialysis, wherein the dialysis time is 72 hours, and changing water every 3 hours to prepare the fibroin solution with the mass percentage of 5%; 0.8g of polyethylene oxide was dissolved in 9.2g of deionized water, and stirred for 12 hours to be completely dissolved, to obtain a polyethylene oxide solution having a mass percentage of 8%.

(2) 4g of silk fibroin solution and 1g of polyoxyethylene solution are uniformly mixed, and after 30 minutes of mixing, electrostatic spinning is carried out, wherein the spinning voltage is 7kV, the receiving distance is 15cm, the flow rate of a spinning solution is 1ml/h, the ambient temperature is 30 ℃, the ambient relative humidity is 25%, and the spinning time is 15 minutes. And soaking the obtained nanofiber filter membrane in ethanol for 10 minutes to complete phase transformation so that the nanofiber filter membrane is insoluble in water. And then soaking the filtering membrane in deionized water for 24 hours to dissolve and etch the polymer phase, thereby obtaining the silk fibroin nanofiber filtering membrane with the surface having the micro-nano structure. Fig. 1 is a scanning electron microscope photograph of a silk fibroin nanofiltration membrane with a micro-nano structure on the surface.

Example 2

(1) Firstly, putting natural domestic silkworm silk into a boiled sodium carbonate solution with the mass percentage of 0.5%, degumming for 60 minutes, removing surface sericin, cleaning to obtain silk fibroin, and placing the silk fibroin in a vacuum oven at 30 ℃ for vacuum drying for 2 days; dissolving degummed fibroin in 9.5M lithium bromide aqueous solution at 60 ℃, dissolving for 3 hours, filtering, placing the fibroin solution in a dialysis box, sealing, soaking in deionized water for dialysis, wherein the dialysis time is 48 hours, and changing water every 3 hours to prepare the fibroin solution with the mass percentage of 9%; 0.4g of polyethylene oxide was dissolved in 9.6g of deionized water, and stirred for 12 hours to be completely dissolved, to obtain a 4% by mass polyethylene oxide solution.

(2) 4g of silk fibroin solution and 1g of polyoxyethylene solution are uniformly mixed, and after 30 minutes of mixing, electrostatic spinning is carried out, wherein the spinning voltage is 13kV, the receiving distance is 30cm, the flow rate of a spinning solution is 1ml/h, the ambient temperature is 25 ℃, the ambient relative humidity is 45%, and the spinning time is 15 minutes. And soaking the obtained nanofiber filter membrane in ethanol for 15 minutes to complete phase transformation so that the nanofiber filter membrane is insoluble in water. And then soaking the filtering membrane in deionized water for 36 hours to dissolve and etch the polymer phase, thereby obtaining the silk fibroin nanofiber filtering membrane with the surface having the micro-nano structure. Fig. 2 is a scanning electron microscope photograph of the silk fibroin nanofiltration membrane with the surface having the micro-nano structure.

Example 3

(1) Firstly, putting natural domestic silkworm silk into a boiled sodium carbonate solution with the mass percentage of 0.5%, degumming for 60 minutes, removing surface sericin, cleaning to obtain silk fibroin, and placing the silk fibroin in a vacuum oven at 30 ℃ for vacuum drying for 2 days; dissolving degummed fibroin in 9M lithium bromide aqueous solution at 60 ℃, dissolving for 3 hours, filtering, placing the fibroin solution in a dialysis box, sealing, and immersing in deionized water for dialysis, wherein the dialysis time is 72 hours, and water is changed every 6 hours to prepare 8% fibroin solution by mass percentage; 0.8g of polyvinyl alcohol is dissolved in 9.2g of deionized water, and the mixture is stirred for 12 hours until the polyvinyl alcohol is completely dissolved, so that a polyvinyl alcohol solution with the mass percent of 8% is obtained.

(2) 2g of silk fibroin solution and 2g of polyvinyl alcohol solution are uniformly mixed, and after 30 minutes of mixing, electrostatic spinning is carried out, wherein the spinning voltage is 10kV, the receiving distance is 22cm, the flow rate of a spinning solution is 0.8ml/h, the ambient temperature is 28 ℃, the ambient relative humidity is 35%, and the spinning time is 20 minutes. And soaking the obtained nanofiber filter membrane in ethanol for 10 minutes to complete phase transformation so that the nanofiber filter membrane is insoluble in water. And then soaking the filtering membrane in deionized water for 48 hours to dissolve and etch the polymer phase, thereby obtaining the silk fibroin nanofiber filtering membrane with the surface having the micro-nano structure.

Example 4

(1) Firstly, putting natural domestic silk into a boiled sodium carbonate solution with the mass percentage of 1%, degumming for 30 minutes, removing surface sericin, cleaning to obtain silk fibroin, and placing the silk fibroin in a vacuum oven with the temperature of 30 ℃ for vacuum drying for 2 days; dissolving degummed fibroin in 9.5M lithium bromide aqueous solution at 60 ℃, dissolving for 3 hours, filtering, placing the fibroin solution in a dialysis box, sealing, soaking in deionized water for dialysis, wherein the dialysis time is 48 hours, and changing water every 4 hours to prepare 6% fibroin solution by mass percent; dissolving 1g of polyacrylamide into 9g of deionized water, and stirring for 12 hours at 60 ℃ until the polyacrylamide is completely dissolved to obtain a polyacrylamide solution with the mass percentage of 10%.

(2) 5g of silk fibroin solution and 1g of polyacrylamide solution are uniformly mixed, and after 30 minutes of mixing, electrostatic spinning is carried out, the spinning voltage is 10kV, the receiving distance is 22cm, the flow rate of a spinning solution is 0.8ml/h, the ambient temperature is 28 ℃, the ambient relative humidity is 35%, and the spinning time is 20 minutes. And soaking the obtained nanofiber filter membrane in ethanol for 10 minutes to complete phase transformation so that the nanofiber filter membrane is insoluble in water. And then soaking the filtering membrane in deionized water for 36 hours to dissolve and etch the polymer phase, thereby obtaining the silk fibroin nanofiber filtering membrane with the surface having the micro-nano structure.

Claims

1. a preparation method of the silk fibroin nanofiltration membrane with micro-nano structure on the surface, is characterized in that, comprises the following steps:

(1) Preparation of silk fibroin solution: first degumming the silk through a sodium carbonate aqueous solution to obtain degummed silk, dissolving the degummed silk in a lithium bromide solution to obtain a silk fibroin-lithium bromide solution, and dialysis the silk fibroin-lithium bromide solution, Filtration, centrifugation and concentration to obtain a silk fibroin solution with a mass percentage of 5-20;

(2) Preparation of polymer solution: Dissolve the polymer in deionized water, stir at room temperature until it is completely dissolved, and obtain a polymer solution with a mass percentage of 2-10%; the polymer includes polyethylene oxide, polyethylene One or a combination of alcohol, polyvinyl alcohol and polyacrylamide;

(3) Preparation of silk fibroin and polymer mixed electrospinning solution: blending silk fibroin solution and polymer solution, fully stirring at room temperature to obtain a blended electrospinning solution, and the formed uniform and stable mixed spinning solution The silk fluid concentration is 5-15%; the mass ratio of the silk fibroin solution and the polymer solution is (1:1)-(6:1);

(4) Electrospinning to prepare nanofiber filter membrane: electrospin the above spinning solution to obtain nanofiber filter membrane;

(5) Post-treatment of nanofiber filter membrane: soak the prepared nanofiber filter membrane in ethanol for 10-20 minutes to complete the phase transition and make it insoluble in water; then soak the filter membrane in deionized water to dissolve and etch away the polymer phase , finally obtaining a silk fibroin nanofiber filter membrane with a micro-nano structure on the surface; the ethanol concentration is 80-100%, and the soaking etching time is 12-36 hours.

2. the preparation method of the silk fibroin nanofiltration membrane that a kind of surface has micro-nano structure according to claim 1, is characterized in that: the mass percent of the sodium carbonate aqueous solution in described step (1) is 0.5-1% , the degumming time is 30-60 minutes, and the molar concentration of the lithium bromide aqueous solution is 8.5-9.5M.

3. the preparation method of the silk fibroin nanofiltration membrane of a kind of surface with micro-nano structure according to claim 1, is characterized in that: in described step (4), electrospinning technological parameter is: spinning voltage is 7 -20kV, receiving distance 15-30cm, spinning solution flow rate 0.1-2.0ml/h, ambient temperature 25-30°C, ambient relative humidity 25-55%, spinning time 10-30 minutes.

4. A silk fibroin nanofiltration membrane with micro-nano structure on the surface obtained by the preparation method according to claim 1.

5 . The silk fibroin nanofiltration membrane with a micro-nano structure on the surface according to claim 4 , wherein the parameters of the filtering membrane are: the fiber diameter is 100-1000 nm, and the membrane thickness is 2-1 . 0um, the fiber membrane porosity is 60–85%, and the pore size is 20–500nm.

6. The application of the silk fibroin nanofiltration membrane with micro-nano structure on the surface according to claim 4 or 5, characterized in that, it is applied in the preparation of civil or industrial air filtration equipment.

7. The application of the silk fibroin nanofiltration membrane with a micro-nano structure on the surface according to claim 6, characterized in that it is applied to a mask, an air conditioner, an air purifier or its filter element.