Preparation method of zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane

Abstract

The application discloses a preparation method of a zein / cinnamaldehyde essential oil efficient low-resistance nanofiber air filtration membrane, and comprises the following steps: dissolving zein in a solvent, fully stirring to form a spinning solution, wherein the solvent is a mixed solution of ethanol and cinnamaldehyde essential oil; and performing electrostatic spinning on the spinning solution to obtain an antibacterial efficient low-resistance air filtration membrane with uniform beaded nanofibers. The preparation steps are simple and not complicated, the zein is rich in sulfur-containing amino acids, the protein molecules are connected by strong disulfide bonds and hydrophobic bonds, and the zein is easy to form a film. The high boiling point feature of cinnamaldehyde enables the mixed solution system to realize delayed volatilization, slows down the solidification of the solution caused by ethanol volatilization in the spinning process, and thus prevents the problem of needle blockage, so that the spinning process is smoother, the diameter of the prepared fiber is reduced, the fiber has a beaded structure, and high-efficiency low-resistance air filtration is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of air filtration membranes, in particular to a preparation method of a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane. BACKGROUND

[0002] With the rapid development of the global economy, air pollution problems are increasingly serious. At the same time, the rampant spread of other influenza also seriously threatens public health. The electrospinning nanofiber membrane prepared based on the electrospinning technology has the advantages of small fiber diameter, large specific surface area, high porosity and easy modification and is widely applied to the development of high-efficiency low-resistance air filtration membranes. The existing technology has disclosed many methods for preparing antibacterial nanofiber air filtration membranes, for example: a preparation method of antibacterial nanofiber (CN113638073A), a preparation and application of antibacterial electrospinning nanofiber air filtration material (CN108993167A) and the like. They all adopt the method of introducing natural base materials to endow the nanofiber membrane with antibacterial performance, however, they all have the common problem that high-efficiency low-resistance air filtration cannot be realized. A corn protein-based food packaging material and a preparation method thereof (CN106567143A) have prepared a green and environmentally friendly corn protein-based food packaging material through relevant technical improvement. However, the application of zein to the field of air filtration to realize high-efficiency low-resistance air filtration performance is relatively rare. The present application finds that, based on the zein material, the cinnamaldehyde essential oil is introduced to construct a solution system with delayed volatilization to prepare a nanofiber membrane, and the filtration effect on PM0.3 is remarkable. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a preparation method of a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane, which solves the problem that the existing air filtration materials in the prior art cannot realize high-efficiency low-resistance air filtration.

[0004] To achieve the above-mentioned purpose, the present application provides a preparation method of a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane, which comprises the following steps:

[0005] Dissolve the zein in a solvent, fully stir to form a spinning solution, and the solvent is a mixed solution of ethanol and cinnamaldehyde essential oil;

[0006] Carry out electrospinning on the spinning solution to obtain an antibacterial high-efficiency low-resistance air filtration membrane with uniform beaded nanofibers.

[0007] Further, the mass fraction of the zein in the spinning solution is 15-25%.

[0008] Further, the volume ratio of ethanol and cinnamaldehyde essential oil in the solvent is 2-10:1-6.

[0009] Further, the volume ratio of ethanol and cinnamaldehyde essential oil in the solvent is 2-10:1-6.

[0010] Further, the stirring time is 8-24h.

[0011] Further, the electrospinning temperature is 20-50℃, the humidity is 20-80%, the spinning voltage is 16-25kV, the receiving distance is 10-15cm, and the liquid supply rate is 0.15-0.5mL / h.

[0012] Correspondingly, the application also provides a corn protein zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane prepared by the above preparation method.

[0013] The above technical solution has the following beneficial effects:

[0014] (1) In the preparation method provided by the application, all components are selected from bio-based materials, which is expected to slow down energy consumption and environmental pollution. Corn protein zein is rich in sulfur-containing amino acids, and protein molecules are connected by strong disulfide bonds and hydrophobic bonds, which is easy to form a film. The high boiling point characteristics of cinnamaldehyde enable the mixed solution system to achieve delayed volatilization, slow down the problem of needle blockage caused by ethanol volatilization during the spinning process, and make the spinning process smoother. The prepared fiber has a smaller diameter, and a large number of extremely fine nanofibers with a diameter of less than 80nm are obtained, which is beneficial to realize high-efficiency low-resistance air filtration and antibacterial properties.

[0015] (2) The prepared corn protein zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane has a higher specific surface area, a smaller pore size, and an enhanced electrostatic effect caused by extremely fine diameter, which can effectively intercept and adsorb particles, greatly improve the air filtration performance, and the filtration efficiency of PM0.3 reaches more than 99%, and the resistance pressure drop is not more than 70Pa, successfully realizing high-efficiency low-resistance air filtration.

[0016] (3) The air filtration membrane uses corn protein zein as the basic raw material, has a certain hydrophobic ability, can effectively avoid the adhesion of bacteria, and indirectly improves the antibacterial ability. The high loading amount of cinnamaldehyde in the air filtration membrane makes the prepared air filtration membrane have good antibacterial performance, and due to the functional groups of cinnamaldehyde, the bacteria can be inactivated due to the rupture of the cell membrane. Therefore, the prepared corn protein zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane can realize high-efficiency antibacterial performance, and the antibacterial rates of Escherichia coli and Staphylococcus aureus are not less than 99%.

[0017] (4) Delayed volatile solution system to achieve efficient low resistance nanofiber air filtration membrane, using one-step electrospinning blended polymer solution preparation, effectively avoid nanotoxicity, improve the preparation efficiency, reduce the preparation threshold, will help to greatly promote its batch preparation, promote its commercial application. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Preparation process of corn alcohol soluble protein / cinnamaldehyde essential oil efficient low resistance nanofiber air filtration membrane.

[0019] Figure 2 Preparation flow chart of corn alcohol soluble protein / cinnamaldehyde essential oil efficient low resistance nanofiber air filtration membrane.

[0020] Figure 3 Scanning electron microscope photos of corn alcohol soluble protein / cinnamaldehyde essential oil efficient low resistance nanofiber air filtration membrane.

[0021] Figure 4 Scanning electron microscope photos of corn alcohol soluble protein / deionized water nanofiber membrane.

[0022] Figure 5 Solution volatilization of corn alcohol soluble protein / cinnamaldehyde essential oil and corn alcohol soluble protein / deionized water.

[0023] Figure 6 Water contact angle of corn alcohol soluble protein / cinnamaldehyde essential oil efficient low resistance nanofiber air filtration membrane and corn alcohol soluble protein / deionized water nanofiber membrane. DETAILED DESCRIPTION

[0024] In order to make the technical content, structural features, purposes and effects of the technical scheme clear, the following will be described in detail in combination with specific embodiments and with reference to the drawings.

[0025] Please refer to Figures 1 to 6 , the embodiment provides a preparation method of corn alcohol soluble protein / cinnamaldehyde essential oil efficient low resistance nanofiber air filtration membrane, comprising the following steps:

[0026] (1) Dissolve corn alcohol soluble protein in solvent, fully stir to form spinning solution, and the solvent is a mixed solution of ethanol and cinnamaldehyde essential oil;

[0027] (2) Electrospinning the spinning solution obtained in (1) to obtain a high-efficiency low-resistance air filtration membrane with uniform bead string-shaped nanofiber structure and stable performance.

[0028] The flow of the preparation process is shown in Figure 1 and Figure 2 , the spinning solution is electrospun to obtain a large number of extremely fine nanofibers with bead string structure, as shown in Figure 3As shown, the average diameter of the fibers is 80 nm, wherein the average diameter of the ultrafine fibers is 50 nm, and the coverage is 100%.

[0029] According to a preferred embodiment of the present application, the mass fraction of zein in the spinning solution is 15-25%.

[0030] According to a preferred embodiment of the present application, the volume ratio of ethanol to cinnamaldehyde essential oil in the solvent is 2-10: 1-6.

[0031] According to a preferred embodiment of the present application, the volume ratio of ethanol to cinnamaldehyde essential oil in the solvent is 3-6: 2-5.

[0032] According to a preferred embodiment of the present application, the stirring time is 8-24 h.

[0033] According to a preferred embodiment of the present application, the temperature for electrospinning is 20-50℃, the humidity is 20-80%, the spinning voltage is 16-25kV, the receiving distance is 10-15cm, and the liquid supply rate is 0.15-0.5mL / h.

[0034] The specific embodiments of the present application are as follows:

[0035] Example 1

[0036] At room temperature, 4.4g of ethanol and 3.6g of cinnamaldehyde essential oil are prepared into a compound organic solvent with a volume ratio of 5 / 4. 2g of zein with a mass concentration of 20wt% is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 20%.

[0037] Under the conditions of a temperature of 24℃, a humidity of 50%, a spinning voltage of 24kV, a receiving distance of 12cm, and a liquid supply rate of 0.15mL / h, electrospinning is carried out, and a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane is obtained.

[0038] Example 2

[0039] At room temperature, 4.4g of ethanol and 3.6g of cinnamaldehyde essential oil are prepared into a compound organic solvent with a volume ratio of 5 / 4. 1.76g of zein with a mass concentration of 18wt% is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 18%.

[0040] Under the conditions of a temperature of 30℃, a humidity of 60%, a spinning voltage of 22kV, a receiving distance of 10cm, and a liquid supply rate of 0.3mL / h, electrospinning is carried out, and a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane is obtained.

[0041] Example 3

[0042] Take 5.3g ethanol, 2.6g cinnamaldehyde essential oil to prepare a compound organic solvent with a volume ratio of 6 / 3 at room temperature. According to the mass concentration of 21wt%, 2.1g of zein is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 21%.

[0043] Under the conditions of temperature 40℃, humidity 40%, spinning voltage 20kV, receiving distance 12cm, and liquid supply rate 0.2mL / h, electrospinning is carried out to obtain a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane.

[0044] Example 4

[0045] Take 5.3g ethanol, 2.6g cinnamaldehyde essential oil to prepare a compound organic solvent with a volume ratio of 6 / 3 at room temperature. According to the mass concentration of 21wt%, 2.1g of zein is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 21%.

[0046] Under the conditions of temperature 35℃, humidity 65%, spinning voltage 18kV, receiving distance 15cm, and liquid supply rate 0.4mL / h, electrospinning is carried out to obtain a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane.

[0047] Example 5

[0048] Take 5.3g ethanol, 2.6g cinnamaldehyde essential oil to prepare a compound organic solvent with a volume ratio of 6 / 3 at room temperature. According to the mass concentration of 21wt%, 2.1g of zein is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 21%.

[0049] Under the conditions of temperature 30℃, humidity 60%, spinning voltage 16kV, receiving distance 13cm, and liquid supply rate 0.2mL / h, electrospinning is carried out to obtain a zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane.

[0050] Example 6

[0051] Take 5.3g ethanol, 2.6g cinnamaldehyde essential oil to prepare a compound organic solvent with a volume ratio of 6 / 3 at room temperature. According to the mass concentration of 21wt%, 2.1g of zein is weighed and added to the compound organic solvent, and continuously stirred with a magnetic stirrer for 12h until fully dissolved, to obtain a zein spinning solution with a mass fraction of 21%.

[0052] The electrospinning is carried out under the conditions of a temperature of 40℃, a humidity of 70%, a spinning voltage of 25kV, a receiving distance of 16cm, and a liquid supply rate of 0.5mL / h, so that the zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane is obtained.

[0053] The air filtration membranes prepared in Examples 1-6 are tested for air filtration performance using 300nm-diameter sodium chloride aerosol particles, and the filtration efficiency is above 99% and the resistance pressure drop is not more than 70Pa. The air filtration membranes prepared in Examples 1-6 are tested for antibacterial performance according to GB / T 20944.3-2008 using E. coli and Staphylococcus aureus, and the antibacterial rates for E. coli and Staphylococcus aureus are not less than 99%, and the specific test results are shown in Table 1.

[0054] Table 1 Performance of the uniform beaded antibacterial high-efficiency low-resistance air filtration membranes prepared in Examples 1-6

[0055]

[0056]

[0057] As shown in Table 1, the antibacterial air filtration membranes prepared by the method of the present application have high filtration efficiency, low air resistance, and strong antibacterial performance, and have a filtration efficiency of above 99% for 300nm-sized sodium chloride particles under a pressure drop of less than 70Pa; at the same time, the bactericidal rates for E. coli and Staphylococcus aureus are not less than 99%. In addition, the air filtration membranes have no nanotoxicity, meeting the safety requirements for personal protection; at the same time, they are all degradable components and can be completely degraded in a natural environment. Therefore, the zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filtration membrane can achieve safe personal protection under the premise of meeting the requirements of high-efficiency low-resistance air filtration, while reducing the environmental burden of waste air filtration materials.

[0058] Example 7

[0059] Compared with Example 1, the different point is that in the preparation: the mass fraction of zein in the spinning solution is 15%, the mass ratio of ethanol to cinnamaldehyde essential oil in the spinning solution is 4 / 3, the electrospinning is carried out under the conditions of a temperature of 50℃, a humidity of 30%, a spinning voltage of 16kV, a receiving distance of 13cm, and a liquid supply rate of 0.45mL / h, so that the air filtration membrane is obtained.

[0060] Example 8

[0061] The different point compared with Example 1 is that, during preparation: the mass fraction of zein in the spinning solution is 23%, the spinning mass ratio of ethanol and cinnamaldehyde essential oil in the spinning solution is 8 / 5, electrospinning is carried out under the conditions of temperature 20℃, humidity 50%, spinning voltage 19kV, receiving distance 11cm, and liquid supply rate 0.5mL / h, and thus the air filtration membrane is obtained.

[0062] Example 9

[0063] The different point compared with Example 1 is that, during preparation: the mass fraction of zein in the spinning solution is 24%, the spinning mass ratio of ethanol and cinnamaldehyde essential oil in the spinning solution is 10 / 7, electrospinning is carried out under the conditions of temperature 25℃, humidity 45%, spinning voltage 22kV, receiving distance 14cm, and liquid supply rate 0.25mL / h, and thus the air filtration membrane is obtained.

[0064] Example 10

[0065] The different point compared with Example 1 is that, during preparation: the mass fraction of zein in the spinning solution is 17%, the spinning mass ratio of ethanol and cinnamaldehyde essential oil in the spinning solution is 5 / 5, electrospinning is carried out under the conditions of temperature 50℃, humidity 40%, spinning voltage 17kV, receiving distance 12cm, and liquid supply rate 0.3mL / h, and thus the air filtration membrane is obtained.

[0066] Example 11

[0067] The different point compared with Example 1 is that, during preparation: the mass fraction of zein in the spinning solution is 21%, the spinning mass ratio of ethanol and cinnamaldehyde essential oil in the spinning solution is 5 / 6, electrospinning is carried out under the conditions of temperature 30℃, humidity 75%, spinning voltage 20kV, receiving distance 14cm, and liquid supply rate 0.35mL / h, and thus the air filtration membrane is obtained.

[0068] Example 12

[0069] The different point compared with Example 1 is that, during preparation: the mass fraction of zein in the spinning solution is 23%, the spinning mass ratio of ethanol and cinnamaldehyde essential oil in the spinning solution is 2 / 5, electrospinning is carried out under the conditions of temperature 40℃, humidity 65%, spinning voltage 18kV, receiving distance 15cm, and liquid supply rate 0.15mL / h, and thus the air filtration membrane is obtained.

[0070] To further prove that the cinnamaldehyde with high boiling point introduced by the prepared air filter membrane of the application brings the effect of delaying volatilization of the solution system, two kinds of electrospinning systems with delayed volatilization and normal volatilization are constructed, wherein the delayed volatilization electrospinning system is composed of ethanol and cinnamaldehyde essential oil, and the volume ratio is 6 / 3 (5.3 g of ethanol and 2.6 g of cinnamaldehyde essential oil are taken to prepare); the normal volatilization electrospinning system is composed of ethanol and deionized water, and the volume ratio is 6 / 3 (5.3 g of ethanol and 2.6 g of deionized water are taken to prepare). Then 2 g of zein is weighed and added into the compounded organic solvent, and a magnetic stirrer is used for continuous stirring for 12 h until the zein is fully dissolved, to obtain a zein spinning solution. The electrospinning is carried out under the conditions of a temperature of 24 ℃, a humidity of 50%, a spinning voltage of 24 kV, a receiving distance of 12 cm, and a liquid supply rate of 0.15 mL / h.

[0071] The delayed volatilization system increases the boiling point of the solution system due to the addition of cinnamaldehyde essential oil, effectively delays the jet solidification in the electrospinning process, and improves the preparation efficiency and morphology of the zein / cinnamaldehyde nanofiber. The fiber is finer (see Figure 3 ), and has a pearl string structure, thereby improving the air filtration performance. Under the same conditions, the natural volatilization system uses ethanol and deionized water as solvents, and the boiling point of the obtained solution system is lower, and the volatility is stronger, which leads to jet solidification in the electrospinning process, resulting in the presence of particles, and increasing the overall fiber diameter (see Figure 4 ).

[0072] The solution volatilization of the zein / cinnamaldehyde essential oil high-efficiency low-resistance nanofiber air filter membrane (see Figure 5 ), and the water contact angle (see Figure 6 ). After 5 g of the electrospinning solution of zein / cinnamaldehyde essential oil is placed in air for 120 min, the mass of the solution remains 4.89 g; and after 5 g of the electrospinning solution of zein / deionized water is placed in air for 120 min, the mass of the solution remains 4.77 g. The water contact angle of the nanofiber membrane obtained from the electrospinning solution of zein / cinnamaldehyde essential oil is 50°, which is higher than the water contact angle of the nanofiber membrane obtained from the electrospinning solution of zein / deionized water, which is 30°. It is proved that the addition of cinnamaldehyde essential oil helps to improve the delayed volatilization characteristics of the solution system, and improves the hydrophobicity of the nanofiber membrane.

[0073] It is to be noted that, in the present text, terms such as first and second, and the like, merely serve to identify a difference between one entity or action and another entity or action, and do not necessarily require or imply that there is any such actual relationship or order between these entities or actions. Moreover, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or apparatuses that comprise a list of elements are not required to comprise only those elements, but can include other elements not expressly listed or inherent to such processes, methods, articles, or apparatuses. Without further limitation, an element preceded by "comprises a" or "comprises" does not, without more limitations, preclude the existence of further elements of the process, method, article, or apparatus that includes the element. Furthermore, in the present text, "greater than", "less than", "exceed", and the like are understood to exclude the number itself; "and above", "and below", "and within", and the like are understood to include the number itself.

[0074] Although the above-mentioned embodiments have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept, so the above description is only for the embodiments of the present application, and does not limit the patent protection scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a high-efficiency, low-resistance nanofiber air filter membrane of zein / cinnamaldehyde essential oil, characterized in that, Includes the following steps: (1) Dissolve zein in a solvent and stir thoroughly to form a spinning solution. The solvent is a mixture of ethanol and cinnamaldehyde oil. The mass fraction of zein in the spinning solution is 15-25%, and the volume ratio of ethanol to cinnamaldehyde oil in the solvent is 2-10:1-6. (2) The spinning solution is electrospun to obtain an antibacterial, high-efficiency, low-resistance air filter membrane with uniform beaded nanofibers.

2. The preparation method according to claim 1, characterized in that, The volume ratio of ethanol to cinnamaldehyde essential oil in the solvent is 3-6:2-5.

3. The preparation method according to claim 1, characterized in that, The stirring time is 8-24 hours.

4. The preparation method according to claim 1, characterized in that, The electrospinning temperature is 20-50℃, the humidity is 20-80%, the spinning voltage is 16-25kV, the receiving distance is 10-15cm, and the liquid supply rate is 0.15-0.5mL / h.

5. A high-efficiency, low-resistance nanofiber air filter membrane made of zein / cinnamaldehyde essential oil, characterized in that, It is prepared by the preparation method described in claim 1.

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