Heterojunction mosquito repellent composite material based on plant extracts and preparation method and application thereof

Abstract

The present invention relates to the field of mosquito repellent technology, and discloses a heterojunction mosquito repellent composite material based on plant extracts and its preparation method and application, including: N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide are dissolved in anhydrous ethanol to obtain a mixture A; ZIF8 and polyethylene glycol are dissolved in a solvent to obtain a mixture B; Mixture A is added to mixture B, ultrasonic stirring is uniform, and it is continuously placed in an ultrasonic environment for 12-48h to obtain a mixture C; Bi2O3 powder is dissolved in an acid solution to obtain a mixture D, and mixture D is added to mixture C, ultrasonic stirring is uniform, and mixture E is obtained; Acorus calamus extract is added to mixture E, and after stirring, it is placed in a hydrothermal reactor for treatment; The product is centrifuged and washed to obtain a heterojunction mosquito repellent composite material. The present invention has a lasting mosquito repellent effect, has antibacterial and mildew-proof functions, is environmentally friendly and harmless to the human body.

Description

Technical Field

[0001] The present invention relates to the technical field of mosquito repellent, and in particular to a plant extract-based heterojunction mosquito repellent composite material and a preparation method and application thereof. Background Art

[0002] Mosquito repellents are widely used in many fields such as homes, outdoor activities and public health to effectively prevent mosquito bites and the spread of diseases. The current mosquito repellent products on the market mainly include mosquito repellent liquids, mosquito repellent sprays, mosquito repellent paints, etc., which usually rely on the volatility of chemical mosquito repellents (such as DEET, parcarbyl, lemon eucalyptus oil, etc.) to achieve the mosquito repellent effect. However, traditional chemical mosquito repellents have the following major problems: (1) The effect is not long-lasting: Traditional mosquito repellents usually evaporate in a short time, resulting in a short-term mosquito repellent effect. Especially in high temperature environments, the mosquito repellent evaporates faster and the mosquito repellent effect is significantly weakened; (2) Environmental and health risks: Many chemical mosquito repellents will pollute the environment during use, and some ingredients may have adverse effects on human health, such as skin allergies and respiratory irritation; (3) Poor stability: Under ultraviolet radiation and high temperature conditions, the mosquito repellent ingredients are easily decomposed, resulting in reduced mosquito repellent effect or even failure; (4) Lack of additional functions: Most existing mosquito repellent paints only have mosquito repellent functions, lack additional functions such as antibacterial and mildew resistance, and cannot provide comprehensive protection. Summary of the invention

[0003] One of the purposes of the present invention is to provide a heterojunction mosquito repellent composite material based on plant extracts and a preparation method thereof, wherein the heterojunction mosquito repellent composite material has a lasting mosquito repellent effect, and has antibacterial and mildew-proof functions, is environmentally friendly and harmless to human health.

[0004] The second purpose of the present invention is to provide an application of a heterojunction mosquito repellent composite material in a multifunctional coating, wherein the heterojunction mosquito repellent composite material can enable the multifunctional coating to have a lasting mosquito repellent effect.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] On the one hand, a method for preparing a heterojunction mosquito repellent composite material based on plant extracts is provided, comprising the following steps:

[0007] S10, dissolving N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) in anhydrous ethanol to prepare a mixture A; dissolving ZIF8 and polyethylene glycol in a solvent to prepare a mixture B;

[0008] S20, adding mixture A to mixture B, stirring evenly with ultrasound, and then placing in an ultrasonic environment for 12 h to 48 h to obtain mixture C;

[0009] S30, dissolving Bi2O3 powder in an acid solution to obtain a mixture D, and adding the mixture D to the mixture C, stirring uniformly with ultrasonic waves to obtain a mixture E;

[0010] S40, adding the plant extract to the mixture E, stirring evenly, and placing in a hydrothermal reactor for treatment;

[0011] S50, centrifuging and washing the product of step S40 to obtain a heterojunction mosquito repellent composite material;

[0012] Among them, the plant extract is Acorus calamus extract.

[0013] The present invention combines ZIF8, Bi2O3, PEG and Acorus calamus extract, and the synergistic effect between ZIF8, Bi2O3, PEG and Acorus calamus extract can significantly improve the durability, environmental friendliness and antibacterial efficacy of the mosquito repellent effect of the heterojunction mosquito repellent composite material. Among them, ZIF8 is a metal organic framework material with a highly ordered three-dimensional pore structure, and its pore size is usually between 0.34 and 0.38 nanometers. This unique pore structure provides a nano-confinement effect on the mosquito repellent molecules. After the mosquito repellent is loaded into the pores of ZIF8, the adsorption of the mosquito repellent molecules by the pore walls of ZIF8 can effectively reduce its volatilization rate and realize the slow release function. The role of polyethylene glycol (PEG) in this system is not only as a carrier of the mosquito repellent, but also in the bridging effect given by its molecular structure. The long-chain molecules of PEG can effectively reduce the interfacial energy between different materials and prevent the separation and agglomeration of the heterojunction by interacting with the interface of ZIF8 and Bi2O3. In addition, the ether bonds on the PEG molecular chain can form hydrogen bonds or van der Waals forces with the surface of Bi2O3, thereby enhancing the structural stability of the heterojunction mosquito repellent composite material and improving the dispersibility and stability of the mosquito repellent in different environments. Bi2O3 is an efficient photocatalytic material. After absorbing photons, electrons jump to the conduction band to generate electron-hole pairs. These excited electrons and holes can react with surrounding oxygen and water molecules to generate reactive oxygen species (ROS) such as superoxide anions (•O2⁻) and hydroxyl radicals (•OH). These ROS have extremely high oxidizing properties and can destroy bacterial cell walls and nucleic acids, thereby playing a bactericidal role. Acorus tatarinowii extract as a plant mosquito repellent. The heterojunction mosquito repellent composite material in the present invention forms multiple synergistic effects through the organic combination of ZIF8, Bi2O3 and PEG. First, the nano-confinement effect of ZIF8 and the sustained release effect of PEG synergize to significantly prolong the release time of the active ingredients with mosquito repellent efficacy in the Acorus tatarinowii extract, ensuring its long-lasting mosquito repellent. Secondly, the reactive oxygen species generated by Bi2O3 not only have a direct repellent effect on mosquitoes, but also kill pathogenic microorganisms in the environment through its efficient oxidation ability, thus providing dual protection. Finally, while improving the biocompatibility of the material, PEG also enhances the interaction between the mosquito repellent active ingredients in the Acorus calamus extract and other ingredients, ensuring the long-term stability of the entire material system in harsh environments such as high temperature and ultraviolet rays.

[0014] In step S20, ultrasonic treatment in this process can effectively promote the uniform dispersion and combination of different components and avoid the formation of large particle aggregates; secondly, the microbubbles generated by ultrasound during the reaction process can accelerate chemical reactions, improve synthesis efficiency, and enhance the structural uniformity and stability of the composite material.

[0015] In step S30, the acid solution is mainly used for dissolving and stabilizing Bi2O3.

[0016] In step S40, the hydrothermal reaction provides a high temperature and high pressure environment, which significantly promotes the interaction between the components in the composite material. Under this condition, the PEG molecules can effectively form a solid bond with the porous structure of ZIF8 and the surface of Bi2O3, and enhance the uniformity and structural stability of the material through intermolecular interactions such as hydrogen bonds and van der Waals forces, thereby reducing possible structural defects.

[0017] At the same time, the hydrothermal reaction enhances the physical adsorption and chemical stability of the mosquito repellent by improving its encapsulation efficiency in the porous structure of ZIF8. This efficient encapsulation enables the mosquito repellent to be gradually released in a slow-release manner during application, avoiding rapid degradation caused by high temperature or ultraviolet radiation, thereby extending the duration of the mosquito repellent effect.

[0018] On the other hand, a plant extract-based heterojunction mosquito repellent composite material is provided, which is prepared by the preparation method of the plant extract-based heterojunction mosquito repellent composite material.

[0019] On the other hand, there is provided an application of a heterojunction mosquito repellent composite material in a multifunctional coating, wherein the heterojunction mosquito repellent composite material is prepared by the preparation method of the heterojunction mosquito repellent composite material based on plant extracts.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention controls the release rate of the mosquito repellent through the porous structure of ZIF8, and combined with the slow-release effect of PEG, can significantly prolong the duration of the mosquito repellent effect of the heterojunction mosquito repellent composite material. The present invention uses Bi2O3 and plant extracts as main components, reduces the negative impact on the environment and human body, and has good environmental friendliness.

[0022] The present invention proposes a heterojunction mosquito repellent composite material based on plant extracts and its coating application, which significantly improves the durability of the mosquito repellent effect and its additional functions by combining ZIF8, Bi2O3 and PEG. The heterojunction mosquito repellent composite material of the present invention is applied to the coating, which can enable the coating to continuously generate active oxygen species under light, not only prolonging the release time of the mosquito repellent, but also providing additional antibacterial protection, and is suitable for mosquito repellent applications under various environmental conditions.

[0023] The heterojunction mosquito repellent composite material of the present invention has not only the mosquito repellent effect, but also the antibacterial and anti-mildew functions, thereby providing comprehensive protection.

[0024] The heterojunction mosquito repellent composite material of the present invention exhibits good stability under high temperature and ultraviolet irradiation, ensuring long-term effectiveness.

[0025] The present invention can significantly improve the durability, environmental friendliness and antibacterial efficacy of the mosquito repellent effect of the heterojunction mosquito repellent composite material, thereby increasing the service life of the multifunctional coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the antibacterial and mosquito repellent heterojunction composite material according to Example 2 of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the following is described in detail in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0028] The present invention provides a method for preparing a heterojunction mosquito repellent composite material based on plant extracts, comprising the following steps:

[0029] S10, dissolving N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide in anhydrous ethanol to prepare a mixture A; dissolving ZIF8 and polyethylene glycol in a solvent to prepare a mixture B;

[0030] S20, adding mixture A to mixture B, stirring evenly with ultrasound, and then placing in an ultrasonic environment for 12-48 hours to obtain mixture C;

[0031] S30, dissolving Bi2O3 powder in an acid solution to obtain a mixture D, and adding the mixture D to the mixture C, stirring uniformly with ultrasonic waves to obtain a mixture E;

[0032] S40, adding the Acorus calamus extract to the mixture E, stirring evenly, and placing in a hydrothermal reactor for treatment;

[0033] S50, centrifuging and washing the product of step S40 to obtain a heterojunction mosquito repellent composite material.

[0034] Further, in step S10, the mass ratio of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide is (1-2): (1-3), for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1.5:1, 1.5:2, 1.5:2.5, 2:1, 2:1.5, 2:3, etc.; the mass ratio of ZIF8 to the solvent is 0.3%-0.8%, for example, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.4 2%, 0.45%, 0.48%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, etc., the mass ratio of polyethylene glycol to the solvent is 240%~160%, for example, 240%, 235%, 230%, 225%, 220%, 215%, 210%, 205%, 200%, 195%, 190%, 180%, 170%, 160%, etc.; the solvent is a mixture of glycerol and deionized water, and the volume ratio of glycerol to deionized water is 1:2.

[0035] Furthermore, the amount of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride added per 100 ml of anhydrous ethanol is 1.5 g-4.5 g, preferably 2 g-4 g; the amount of N-hydroxysuccinimide added per 100 ml of anhydrous ethanol is 1.5 g-4.5 g, preferably 2 g-4 g.

[0036] Further, in step S30, the mass ratio of Bi2O3 powder to acid solution is 0.3%-0.8%, for example, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, 0.48%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, etc.; the acid solution is selected from nitric acid or hydrochloric acid, and the concentration of the acid solution is 1wt.%-2wt.%, for example, 1.1wt.%, 1.2wt.%, 1.3wt.%, 1.4wt.%, 1.5wt.%, 1.6wt.%, 1.7wt.%, 1.8wt.%, 1.9wt.%, 2wt.%, etc.

[0037] Further, the added amount of Acorus calamus extract is 2wt.%-8wt.%, for example, 2wt.%, 2.1wt.%, 2.2wt.%, 2.3wt.%, 2.5wt.%, 2.8wt.%, 3wt.%, 3.2wt.%, 3.5wt.%, 3.8wt.%, 4wt.%, 4.2wt.%, 4.5wt.%, 4.75wt.%, 5wt.%, 5.5wt.%, 6wt.%, 6.5wt.%, 7wt.%, 7.5wt.%, etc.

[0038] Further, step S40 is specifically as follows: adding the Acorus calamus extract to the mixture E, stirring evenly and placing in a hydrothermal reactor, reacting at 100° C.-150° C. for 4 h-12 h, and then cooling to room temperature.

[0039] Furthermore, in step S50, the centrifugal speed is 6000 rpm-10000 rpm, and ethanol and deionized water are used alternately for washing to obtain a heterojunction mosquito repellent composite material.

[0040] Furthermore, in step S20, the ultrasonic stirring time is 10 min-30 min.

[0041] Provided is a heterojunction mosquito repellent composite material, which is prepared by adopting the preparation method of the heterojunction mosquito repellent composite material based on plant extracts.

[0042] Provided is an application of a heterojunction mosquito repellent composite material in a multifunctional coating. The heterojunction mosquito repellent composite material is prepared by the preparation method of the heterojunction mosquito repellent composite material based on plant extracts.

[0043] Furthermore, the addition amount of the heterojunction mosquito repellent composite material in the multifunctional coating is 2wt.%-15wt.%, preferably 3wt.%-10wt.%, and further preferably 4wt.%-8wt.%.

[0044] Next, the present invention will be described in detail using more specific embodiments.

[0045] Example 1

[0046] Preparation of solution A: Mixture A was prepared by dissolving 2 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride (EDC) and 2 g of N-hydroxysuccinimide (NHS) in 200 ml (about 124 g) of anhydrous ethanol.

[0047] Preparation of solution B: 0.5 g ZIF8 (0.5% by weight of the solvent) and 200 g polyethylene glycol (PEG, 200% by weight of the solvent) were dissolved in 100 g of a solvent consisting of glycerol and deionized water (volume ratio 1:2) to prepare a mixture B.

[0048] Preparation of solution C: Mixture C was prepared by dissolving 0.5 g of Bi2O3 powder in 99.5 g of 2 wt.% dilute nitric acid.

[0049] Mixing: Mixture A was slowly added to mixture B, stirred for 20 minutes under ultrasonic environment, and then continued to be treated in ultrasonic environment for 24 hours to obtain mixture D. Mixture C was slowly added to mixture D and stirred for 12 minutes under ultrasonic environment to obtain mixture E (total mass 528.5 g).

[0050] Reaction: Add 26.4 g of Acorus calamus extract (5% of the total mass) to mixture E, stir evenly and place in a hydrothermal reactor, react at 120°C for 10 hours, and then cool to room temperature.

[0051] Separation and purification: The reaction product was centrifuged at 8000 rpm and washed alternately with ethanol and deionized water for several times to finally obtain the ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material.

[0052] Example 2

[0053] Preparation of solution A: 4 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride (EDC) and 4 g of N-hydroxysuccinimide (NHS) were dissolved in 400 ml (about 248 g) of anhydrous ethanol at a mass ratio of 1:1 to prepare a mixture A.

[0054] Preparation of solution B: Mixture B was prepared by dissolving 0.8 g ZIF8 (0.8% of the solvent mass) and 240 g polyethylene glycol (PEG, 240% of the solvent mass) in 100 g of a solvent consisting of glycerol and deionized water (volume ratio 1:2).

[0055] Preparation of solution C: Mixture C was prepared by dissolving 0.8 g of Bi2O3 powder in 99.2 g of 1 wt.% dilute nitric acid.

[0056] Mixing: Slowly add mixture A to mixture B, stir under ultrasonic environment for 30 minutes, and then continue to treat in ultrasonic environment for 48 hours to obtain mixture D; slowly add mixture C to mixture D and stir under ultrasonic environment for 10 minutes to obtain mixture E (total mass 696.8 g).

[0057] Reaction: 41.8 g of Acorus calamus extract (6% of the total mass) was added to mixture E, stirred evenly, and placed in a hydrothermal reactor to react at 150°C for 5 hours, and then cooled to room temperature.

[0058] Separation and purification: The reaction product was centrifuged at 10,000 rpm and washed several times with ethanol and deionized water alternately to obtain a ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material, the structure of which is shown in Figure 1 shown.

[0059] Example 3

[0060] Preparation of solution A: 3 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride (EDC) and 4.5 g of N-hydroxysuccinimide (NHS) were dissolved in 300 ml (about 236 g) of anhydrous ethanol at a mass ratio of 1:1.5 to prepare mixture A.

[0061] Preparation of solution B: Mixture B was prepared by dissolving 0.58 g ZIF8 (0.58% of the solvent mass) and 215 g polyethylene glycol (PEG, 215% of the solvent mass) in 100 g of a solvent consisting of glycerol and deionized water (volume ratio 1:2).

[0062] Preparation of Solution C: Mixture C was prepared by dissolving 0.6 g of Bi2O3 powder in 99.4 g of 1.5 wt.% dilute nitric acid.

[0063] Mixing: Mixture A was slowly added to mixture B, stirred for 25 minutes under ultrasonic environment, and then continued to be treated in ultrasonic environment for 36 hours to obtain mixture D. Mixture C was slowly added to mixture D and stirred for 15 minutes under ultrasonic environment to obtain mixture E (total mass 659.08 g).

[0064] Reaction: 34.6 g of Acorus calamus extract (accounting for 5.25% of the total mass) was added to mixture E, stirred evenly, and placed in a hydrothermal reactor to react at 130°C for 8 hours, and then cooled to room temperature.

[0065] Separation and purification: The reaction product was centrifuged at 9000 rpm and washed alternately with ethanol and deionized water for several times to finally obtain the ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material.

[0066] Comparative Example 1

[0067] This comparative example is basically the same as the above-mentioned Example 2, except that in the preparation of solution B, the added amount of ZIF8 is 2 grams and the added amount of PEG is 10 grams.

[0068] Comparative Example 2

[0069] This comparative example is basically the same as the above-mentioned Example 2, except that Solution C is prepared by dissolving 0.2 g of Bi2O3 powder in 99.8 g of 1 wt.% dilute nitric acid to prepare Solution C.

[0070] Comparative Example 3

[0071] This comparative example is basically the same as the above-mentioned Example 2, except that the mixing step is as follows: Solution A is poured into Solution B, ultrasonically stirred for 15 minutes, and ultrasonic treatment is continued at room temperature for 2 hours. Solution C is slowly added, and ultrasonic stirring is continued for 6 hours.

[0072] Comparative Example 4

[0073] This comparative example is basically the same as the above-mentioned Example 2, except that solution B is prepared as follows: 1 gram of ZIF8 is dissolved in 100 grams of a solvent consisting of deionized water and glycerol (volume ratio 1:2) at a mass fraction to form solution B, without adding PEG.

[0074] Comparative Example 5

[0075] This comparative example is basically the same as the above-mentioned Example 2, except that the amount of the mosquito repellent (Acorus calamus extract) added in the reaction step is 6.97 grams, so that the mass fraction of the mosquito repellent is 1%, and stirring is continued to be uniform.

[0076] Comparative Example 6

[0077] This comparative example is basically the same as the above-mentioned Example 2, except for the mixing and reaction steps: Solution A, Solution B, and Solution C are mixed and ultrasonically stirred for 12 hours.

[0078] The materials prepared in Examples 1-3 and Comparative Examples 1-6 and conventional mosquito repellent material DEET (as Comparative Example 7) were added to a coating (RL-Runli Grass Interior Wall Water Paint) at a mass fraction of 3% and dispersed evenly, and the performance of the prepared mosquito repellent coating samples was tested.

[0079] The antibacterial performance and durability were tested according to the method specified in GB 21866-2008 “Determination of antibacterial properties and antibacterial effects of antibacterial coatings (paint films)”. The test results are shown in Table 1.

[0080]

[0081] As can be seen from Table 1, the inhibition rates of the heterojunction mosquito repellent composite materials of Examples 1-3 on Escherichia coli and Staphylococcus aureus are between 98% and 99%, showing a very strong antibacterial effect. The antibacterial properties of the materials of Comparative Examples 1 to 6 are significantly inferior to those of the embodiments, with the inhibition rates on Escherichia coli ranging from 55% to 77%, and the inhibition rates on Staphylococcus aureus ranging from 60% to 82%. These data show that, without an optimized composite structure and appropriate antibacterial components, these materials are difficult to provide sufficient antibacterial protection. Comparative Examples 5 and 6 show the worst antibacterial effects, especially the inhibition rate on Staphylococcus aureus is only about 60%. This inefficient antibacterial performance may cause the material to be easily infected by bacteria during use, reducing its service life and sanitary safety. DEET in Comparative Example 7, as a traditional mosquito repellent, performs poorly in terms of antibacterial performance, which shows that although DEET can provide a mosquito repellent effect in a short period of time, it lacks antibacterial properties, making the coating a breeding ground for bacteria during long-term use.

[0082] According to GB / T 28408-2012 "Protective clothing - insect repellent clothing" and GB / T 30126-2013 "Testing and evaluation of mosquito repellent properties of textiles", the mosquito repellent rates of mosquito repellent coating samples were tested at 3h, 6h, 12h and 24h. The test results are shown in Table 2.

[0083]

[0084] As can be seen from Table 2, within the test period of 3 hours to 24 hours, the mosquito repellency rates of Example 1, Example 2 and Example 3 always remain at a high level, all above 93%. This shows that these three composite materials have very effective mosquito repellent effects in a short period of time. Compared with the comparative example, the repellency rates of Examples 1 to 3 are significantly higher at all time points, showing a strong and sustained mosquito repellent effect.

[0085] The mosquito repellent effects of Comparative Examples 1 to 6 were acceptable in the first 3 hours, but the mosquito repellent effects decreased significantly over time, especially after 12 hours and 24 hours, the repellency rate decreased significantly, and the lowest dropped to about 35%. These data show that in actual applications, the mosquito repellent effects of these comparative examples may decline rapidly and are not as durable as the embodiments. At 3 hours, the mosquito repellent effect of Comparative Example 7 was high, reaching 95.6%, but then the repellency rate dropped rapidly, and was only 32.3% at 24 hours. This shows that although DEET is very effective as a mosquito repellent in a short period of time, its effect is not durable, and the mosquito repellent effect decays rapidly over time.

[0086] After the mosquito repellent coating samples were irradiated with ultraviolet rays for 96 hours, mosquito repellency tests were conducted on the 3rd, 7th, 14th, 28th and 56th days to verify the durability of the mosquito repellent effect. The test results are shown in Table 3.

[0087]

[0088] As can be seen from Table 3, in the 56-day durability test, the mosquito repellent effect of Examples 1, 2, and 3 remained above 85%. This shows that these composite materials are not only effective in the short term, but also can maintain efficient mosquito repellent performance for a long time. This reflects the sustained release effect of ZIF8 and PEG in the composite material, which effectively prolongs the release time of the mosquito repellent and makes the mosquito repellent effect more durable. The repellency rates of the materials of Comparative Examples 1 to 6 were unstable within the first 7 days, and dropped rapidly after 14 days, and almost lost their effectiveness at 56 days. The lowest repellency rate of Comparative Example 6 at 56 days was only 15.1%, showing its significant disadvantage in long-term use. These data show that the mosquito repellent effect of the comparative examples lacking the composite material preparation process is unstable and it is difficult to meet the needs of long-term mosquito repellent.

[0089] In the short term (within 3 days), DEET in Comparative Example 7 showed a certain mosquito repellent effect, but as time went on, the repellent rate dropped sharply, and only 5.6% remained at 56 days. This further proves that the mosquito repellent effect of DEET is difficult to maintain for a long time, and it is suitable for short-term use but not for long-term mosquito repellent needs.

[0090] In summary, the heterojunction mosquito repellent composite material of the present invention has significant advantages in mosquito repellent effect and durability. Compared with the comparative examples, the heterojunction mosquito repellent composite materials prepared by Examples 1-3 of the present invention show excellent mosquito repellent effect in both the short and long term, and the mosquito repellent effect is stable and durable. The heterojunction mosquito repellent composite material of the present invention is significantly superior to each comparative example in terms of mosquito repellent effect, antibacterial performance stability and durability.

[0091] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a heterojunction mosquito repellent composite material based on plant extracts, characterized in that: The following steps are involved: 2 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride and 2 g of N-hydroxysuccinimide were dissolved in 200 ml of anhydrous ethanol to prepare a mixture A; 0.5 g of ZIF8 and 200 g of polyethylene glycol were dissolved in 100 g of a solvent consisting of glycerol and deionized water to prepare a mixture B, wherein the volume ratio of glycerol to deionized water was 1:2; Mixture C was prepared by dissolving 0.5 g of Bi2O3 powder in 99.5 g of 2 wt.% dilute nitric acid; Mixture A was added to mixture B, stirred for 20 minutes under ultrasonic environment, and then continued to be treated in ultrasonic environment for 24 hours to obtain mixture D; mixture C was added to mixture D, and stirred for 12 minutes under ultrasonic environment to obtain mixture E; 26.4 g of Acorus calamus extract was added to the mixture E, stirred evenly, and placed in a hydrothermal reactor to react at 120° C. for 10 hours, and then cooled to room temperature; The reaction product was centrifuged at 8000 rpm and washed alternately with ethanol and deionized water for several times to obtain a ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material.

2. A method for preparing a heterojunction mosquito repellent composite material based on plant extracts, characterized in that: The following steps are involved: Dissolve 4 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride and 4 g of N-hydroxysuccinimide in 400 ml of anhydrous ethanol at a mass ratio of 1:1 to prepare a mixture A; 0.8 g of ZIF8 and 240 g of polyethylene glycol were dissolved in 100 g of a solvent consisting of glycerol and deionized water to prepare a mixture B, wherein the volume ratio of glycerol to deionized water was 1:2; Mixture C was prepared by dissolving 0.8 g of Bi2O3 powder in 99.2 g of 1 wt.% dilute nitric acid; Mixture A was added to mixture B, stirred for 30 minutes under ultrasonic environment, and then continued to be treated in ultrasonic environment for 48 hours to obtain mixture D; mixture C was added to mixture D, and stirred for 10 minutes under ultrasonic environment to obtain mixture E; 41.8 g of Acorus calamus extract was added to the mixture E, stirred evenly, and placed in a hydrothermal reactor to react at 150° C. for 5 hours, and then cooled to room temperature; The reaction product was centrifuged at 10,000 rpm and washed alternately with ethanol and deionized water for several times to obtain a ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material.

3. A method for preparing a heterojunction mosquito repellent composite material based on plant extracts, characterized in that: The following steps are involved: 3 g of N(3-dimethylaminopropyl)ethylcarbodiimide hydrochloride and 4.5 g of N-hydroxysuccinimide were dissolved in 300 ml of anhydrous ethanol at a mass ratio of 1:1.5 to prepare a mixture A; 0.58 g of ZIF8 and 215 g of polyethylene glycol were dissolved in 100 g of a solvent consisting of glycerol and deionized water to prepare a mixture B, wherein the volume ratio of glycerol to deionized water was 1:2; Mixture C was prepared by dissolving 0.6 g of Bi2O3 powder in 99.4 g of 1.5 wt.% dilute nitric acid; Mixture A was added to mixture B, stirred for 25 minutes under ultrasonic environment, and then continued to be treated in ultrasonic environment for 36 hours to obtain mixture D; mixture C was added to mixture D, and stirred for 15 minutes under ultrasonic environment to obtain mixture E; 34.6 g of Acorus calamus extract was added to the mixture E, stirred evenly, and placed in a hydrothermal reactor to react at 130° C. for 8 hours, and then cooled to room temperature; The reaction product was centrifuged at 9000 rpm and washed several times with ethanol and deionized water alternately to obtain a ZIF8 / PEG / Bi2O3 heterojunction mosquito repellent composite material.

4. A heterojunction mosquito repellent composite material, characterized in that: The composite mosquito repellent material is prepared by the method for preparing the heterojunction composite mosquito repellent material based on plant extracts as described in any one of claims 1 to 3.

5. Application of a heterojunction mosquito repellent composite material in a multifunctional coating, characterized in that: The heterojunction mosquito repellent composite material is prepared by the preparation method of the heterojunction mosquito repellent composite material based on plant extracts according to any one of claims 1 to 3.

6. The use of the heterojunction mosquito repellent composite material in a multifunctional coating according to claim 5, characterized in that: The heterojunction mosquito repellent composite material is added in an amount of 2wt.%-15wt.% in the multifunctional coating.

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