Methods for improving the biological availability of nanomaterials on plant foliage

Abstract

The present invention discloses a method for improving the biological effectiveness of nanomaterials on the foliage of plants, which belongs to the field of fertilizer technology. The method for improving the biological effectiveness of nanomaterials on the foliage of plants according to the present invention includes preparing NanoSi and CDs, dissolving the obtained NanoSi in ethanol, then adding carbon dots CDs, and slowly stirring the solution until it evaporates to obtain a solid nanocomposite material Nano-CDs. The adhesion ability of the obtained NanoSi-CDs is improved by 50.6%-79.8% compared with CDs, the rain resistance ability is improved by 1 cm, and after spraying NanoSi-CDs on the foliage, the photosynthesis of corn is improved by 110%-140% compared with CDs, the biomass amount is 2-4 times, and the effective period of action is extended by more than 10 days.

Description

[Technical Field]

[0001] The present invention specifically relates to a method for increasing the biological availability of nanomaterials on the foliar surface of plants, and is in the field of fertilizer technology. [Background technology]

[0002] Currently, food demand is increasing significantly, but crop yields are not ideal and, in general, serious environmental problems are occurring. In recent years, the application of nanomaterials in agriculture has become more widespread. Nanomaterials have a lower environmental impact, and their inherent properties, such as small particle size, stronger activity, and higher biological efficacy, have improved the utilization efficiency of nanopesticides and fertilizers by 10% to 30% compared to conventional agricultural fertilizers. The higher utilization efficiency is determined by the method of application of the materials. Generally, foliar spraying is 10% to 40% more efficient than root spraying. Therefore, the biological efficacy of these materials can provide a reliable solution to the agricultural yield crisis. However, because spraying materials on foliage can cause materials to fall off, further improving the material's capture rate on the foliage can further improve the biological efficacy of the materials. Summary of the Invention

[0003] In view of the above technical challenges and application objectives, the object of the present invention is to enhance and improve the biological effectiveness of nanomaterials.

[0004] The technical solution of the present invention is: A method for improving the biological availability of nanomaterials on the foliar surface of plants is provided, Step (1): Mixing ammonia water, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; (2) dissolving the obtained NanoSi in ethanol, adding carbon dot-CDs, and slowly stirring the solution until it evaporates to obtain the solid nanocomposite material Nano-CDs.

[0005] A method for preparing nanocomposite materials with high biological availability on the foliar surface of plants is provided, Step (1): Mixing ammonia water, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; (2) dissolving the obtained NanoSi in ethanol, adding carbon dot-CDs, and slowly stirring the solution until it evaporates to obtain the solid nanocomposite material Nano-CDs.

[0006] In one embodiment of the present invention, in the mixture in step (1), the concentration of aqueous ammonia is 28 wt%.

[0007] In one embodiment of the present invention, in the mixture in step (1), the volume ratio of ammonia water, deionized water, and ethanol is 3:10:70.

[0008] In one embodiment of the present invention, in the mixture in step (1), the formaldehyde solution is a 37 wt% aqueous solution.

[0009] In one embodiment of the present invention, in the mixture in step (1), the mass ratio of formaldehyde solution to deionized water is (0.25-0.3):10.

[0010] In one embodiment of the present invention, the amount of resorcinol added to the mixture in step (1) is 0.2 g / 10 mL of deionized water.

[0011] In one embodiment of the present invention, in the mixture in step (1), the volume fraction of tetraethyl orthosilicate to deionized water is 6%.

[0012] In one embodiment of the present invention, in step (1), while continuing to add formaldehyde and resorcinol to the mixture, the amount of resorcinol added is twice the amount of resorcinol in the mixture.

[0013] In one embodiment of the present invention, in step (1), while continuing to add formaldehyde and resorcinol to the mixture, the amount of formaldehyde added is twice the amount of formaldehyde in the mixture.

[0014] In one embodiment of the present invention, in step (1), the firing may be performed continuously at 550°C for 5 hours.

[0015] In one embodiment of the present invention, step (1) comprises: The process specifically involves adding 3 mL of 28 wt% aqueous ammonia, 10 mL of deionized water, and 70 mL of 95% ethanol (AR) to a solution consisting of 0.28 g of 37 wt% formaldehyde and 0.2 g of resorcinol. The mixture is then magnetically stirred at 500 rpm for 6 hours at room temperature. Tetraethyl orthosilicate (TEOS, AR, >98%, 0.6 mL) is then added and stirred for 30 minutes. Then, 0.4 g of resorcinol and 0.56 g of 37 wt% formaldehyde are added and the mixture is stirred for 2 hours. The resulting solid is centrifuged at 4000 rpm for 10 minutes, washed with ethanol, and dried at 50°C. Finally, the resulting solid is continuously calcined at 550°C (heating rate is 2°C / min) for 5 hours to obtain NanoSi.

[0016] In one embodiment of the present invention, in step (2), carbon dot CDs are obtained by hydrothermal synthesis from citric acid and ethylenediamine.

[0017] In one embodiment of the present invention, the amounts of citric acid and ethylenediamine used are (1 to 2) g:(300 to 350) μL.

[0018] In one embodiment of the present invention, the hydrothermal reaction conditions are 200°C for 12 hours.

[0019] In one embodiment of the present invention, in step (2), the amount of ethanol used relative to NanoSi is 450 mL / 100 mg.

[0020] In one embodiment of the present invention, in step (2), the mass ratio of NanoSi to carbon dots CDs is 1:1.

[0021] In one embodiment of the present invention, in step (2), the rotation speed of the slow stirring is 150 rpm.

[0022] The present invention further prepares nanocomposites with high biological availability on the foliar surface of plants based on the above method.

[0023] The present invention further provides an application of the above method or the above nanocomposite material for improving agricultural yields.

[0024] The present invention has the following beneficial technical effects:

[0025] In the present invention, the adhesion ability of NanoSi-CDs is improved by 50.6% to 79.8% compared to CDs, and the rain resistance is improved by 1 cm.

[0026] In the present invention, after spraying NanoSi-CDs on the leaves, the photosynthesis of corn is improved by 110% to 140% compared to CDs, the biomass amount is 2 to 4 times, and the effective period of action is extended by 10 days or more (sustained release performance). [Brief explanation of the drawings]

[0027] [Figure 1](A) is a TEM image of NanoSi, (B) is a TEM image of CDs, (C) is a TEM image of NanoSi-CDs, (D) is a TEM image of the crystal lattice of CDs loaded on NanoSi, (E) is the PL spectra of CDs and NanoSi-CDs, and (F), (G), and (H) are UV-vis, FTIR, and XPS chromatography images of CDs, NanoSi, and NanoSi-CDs, respectively. [Figure 2] (A) and (B) are the contact angles of CDs and NanoSi-CDs, respectively, when the leaf surface growth angle is 0°. (C) and (D) are the contact angles of CDs and NanoSi-CDs, respectively, when the leaf surface growth angle is 30°. [Figure 3] This figure shows the washout effect of foliar fertilizers CDs, NanoSi, and NanoSi-CDs due to rainfall. A is an artificial rainfall simulator, B is a photograph of the effect of 2.5 cm of rainfall on the 20th day, and C, D, and E are comparisons, respectively. These show the net photosynthetic rate, electron transport rate, and chlorophyll content after experiments with 0.5 cm, 1.5 cm, and 2.5 cm of rainfall when treated with NanoSi, CDs, and NanoSi-CDs. [Figure 4] (A) is a photograph of the effects on the 1st, 10th, and 20th days after spraying the materials, from left to right, respectively. (B)-(H) are photosynthetic parameters such as net photosynthetic rate, chlorophyll A, chlorophyll B, electron transport rate, photosystem 2 (PSII) activity-related genes, photosystem 1 (PSI) activity-related genes, and photosynthetic pathway diagrams. [Figure 5] 1 is a TEM photograph of the composite material obtained in Comparative Example 1. [Figure 6] 1 is a TEM photograph of the composite material obtained in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described below in conjunction with specific examples.

[0029] The examples provided below do not limit the scope of the claims of the present invention, and the steps described do not limit the order of execution. Those skilled in the art will recognize that any improvements made to the present invention in accordance with conventional common knowledge should also be included in the scope of the claims of the present invention.

[0030] Example 1: Preparation of nanomaterials (CDs and NanoSi) and their composites (NanoSi-CDs) (1) Aqueous ammonia (28 wt%, 3 mL), deionized water (10 mL), and ethanol (AR, 95%, 70 mL) are added to a solution consisting of formaldehyde (37 wt%, 0.28 g) and resorcinol (0.2 g). The mixture is magnetically stirred at 500 rpm for 6 hours at room temperature, followed by the addition of tetraethyl orthosilicate (TEOS, AR, >98%, 0.6 mL) and stirring for 30 minutes. Resorcinol (0.4 g) and formaldehyde (37 wt%, 0.56 g) are then added, and the mixture is stirred for 2 hours. The solid is then centrifuged at 4000 rpm for 10 minutes, washed with ethanol, and dried at 50 °C. Finally, the resulting solid is continuously calcined at 550 °C (heating rate is 2 °C / min) for 5 hours to obtain NanoSi.

[0031] (2) CDs are synthesized from citric acid (1.05 g) and ethylenediamine (335 μL) by a hydrothermal method (200 °C and 12 h).

[0032] (3) 100 mg of NanoSi was dissolved in 450 mL of ethanol and sonicated for 6 h. Then, 100 mg of CDs was added. Finally, the solution was slowly stirred at 60 °C and 150 rpm until the solution evaporated, to obtain a solid nano-CDs composite.

[0033] Transmission electron microscopy (TEM) was used to characterize the morphology and dimensions of the CDs, NanoSi, and NanoSi-CDs. Results showed that the NanoSi exhibited a spherical shape, with a large amount of hair-like material on the surface. The diameter was 250.6 ± 30.5 nm, and the hair length was 30.5 ± 6.8 nm (Figure 1A). The CDs had a particle size of 2.55 ± 0.23 nm (Figure 1B). A crystalline lattice of carbon dots was observed on the NanoSi (Figure 1D), confirming the successful loading of CDs onto NanoSi. Fluorescence spectra (Figure 1E) again confirmed the presence of carbon dot fluorescence on NanoSi. UV-vis, FITR, and XPS spectra (Figures 1F–H) of the CDs, NanoSi, and NanoSi-CDs further confirmed the loading of CDs onto NanoSi (Figure 1F–H).

[0034] Example 2: Measurement of adhesion performance of NanoSi A contact angle meter was used to measure the contact angles of 1 μL, 3 μL, and 5 μL of CDs and NanoSi-CDs, respectively, on corn leaf surfaces at growth angles of 0° and 30° (Figure 2). The results showed that the contact angle of NanoSi-CDs on corn leaf surfaces was significantly smaller than that of CDs. The smaller the contact angle, the more hydrophilic the material is, i.e., the less likely it is to fall off, demonstrating improved adhesion of the material to the leaf surface. Table 1 shows the adhesion behavior measured by the contact angle meter, further demonstrating that NanoSi-CDs have a higher adhesion ability than CDs after loading, i.e., the adhesion ability of NanoSi-CDs is 50.6% to 79.8% higher than that of CDs.

[0035] Table 1. Adhesion of CDs and NanoSi-CDs on leaf surfaces TIFF0007721690000001.tif23170 Example 3: Weathertightness experiment To simulate the washout effect of NanoSi-CDs, artificial rainwater was designed by dissolving 3 μmol Mg(NO3)2, 7 μmol MgCl2, 15 μmol CaCl2, 6 μmol NH4Cl, 10 μmol Na2SO4, 62 μmol NaCl, and 8 μmol KCl in ultrapure water. The rainfall process was simulated using a spray bottle method (Figure 3A). The artificial rainwater was poured into a spray bottle, and the "rainwater" was sprayed from the front using a bottle attached to a sprayer with a trigger pump. The bottle was 0.5 m above ground level and approximately 0.3 m away from the corn leaf surface. The spray bottle was adjusted to spray 80 mL of artificial rainwater, equivalent to approximately 0.5 cm of precipitation, for every 100 sprays. The washout effect of NanoSi-CDs was measured at precipitation depths of 0.5, 1.5, and 2.5 cm. Ten replicates were performed for each sample. After the rainfall test, various indicators of the corn crop were measured. The results showed that CDs had almost no effect on corn photosynthesis at 1.5 cm of rainfall, proving that almost all of the CDs were washed away to the ground by rainwater at this precipitation level. However, NanoSi-CDs still maintained a high photosynthesis-promoting effect at 2.5 cm of rainfall. This experiment further demonstrated that NanoSi improves the adhesion ability of CDs on the leaf surface.

[0036] Example 4: Biological Effects of Improved Biological Availability of Materials Corn seedlings that had germinated and grown uniformly were selected and transferred to pots (two plants per pot) containing 1.5 kg of soil. Each plant was infused with 5 mL of CDs, NanoSi, and NanoSi-CDs dispersions (each at a concentration of 10 mg L). -1 The control group was sprayed with ultrapure water (CK). After spraying the materials for 7 consecutive days, the corn leaves were collected on the 1st, 5th, 10th, 15th, and 20th days, and photosynthetic parameters were measured.

[0037] The results showed that after spraying NanoSi-CDs on the leaves, the photosynthesis of corn increased by 110%-140% compared to CDs, the biomass was 2-4 times higher, and the effective period of action was extended by more than 10 days.

[0038] Comparative Example 1: Referring to Example 1, the amount of ethanol used in step (3) is converted to 300 mL and 600 mL (i.e., NanoSi), respectively, and the other matters are not changed to obtain the corresponding composite materials.

[0039] Morphological characterization of the corresponding composites revealed that no crystalline lattice of carbon dots was found on the surface of any of the obtained corresponding composites, clearly indicating that the method was unable to achieve effective loading of carbon dots.

[0040] Comparative Example 2: Referring to Example 1, in step (3), the rotation speed is changed from 150 rpm to 100 rpm and 300 rpm, respectively, and other settings are kept unchanged to obtain the corresponding composite materials.

[0041] Morphological characterization of the corresponding composites revealed that no crystalline lattice of carbon dots was found on the surface of any of the obtained corresponding composites, clearly indicating that the method was unable to achieve effective loading of carbon dots.

Claims

1. 1. A method for improving the biological availability of nanomaterials on the foliar surface of a plant, comprising: Step (1) of mixing aqueous ammonia, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, then adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; (2) dissolving the obtained NanoSi in ethanol, then adding carbon dots CDs, and slowly stirring the solution until the solution evaporates to obtain a solid nanocomposite material Nano-CDs; In the mixture in step (1), the volume fraction of tetraethyl orthosilicate to deionized water is 6%; In step (1), while continuing to add formaldehyde and resorcinol to the mixture, the amount of resorcinol added is twice the amount of resorcinol in the mixture, and the amount of formaldehyde added is twice the amount of formaldehyde in the mixture; In step (2), the amount of ethanol used relative to the amount of NanoSi was 450 mL / 100 mg; In step (2), the mass ratio of NanoSi to carbon dots CDs is 1:1; A method for improving the biological availability of nanomaterials on the leaf surface of a plant, characterized in that in step (2), the rotation speed of the slow stirring is 150 rpm.

2. 1. A method for preparing a nanocomposite material with high biological availability on the foliar surface of a plant, comprising: Step (1) of mixing aqueous ammonia, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, then adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; (2) dissolving the obtained NanoSi in ethanol, then adding carbon dots CDs, and slowly stirring the solution until the solution evaporates to obtain a solid nanocomposite material Nano-CDs; In the mixture in step (1), the volume fraction of tetraethyl orthosilicate to deionized water is 6%; In step (1), while continuing to add formaldehyde and resorcinol to the mixture, the amount of resorcinol added is twice the amount of resorcinol in the mixture, and the amount of formaldehyde added is twice the amount of formaldehyde in the mixture; In step (2), the amount of ethanol used relative to the amount of NanoSi was 450 mL / 100 mg; In step (2), the mass ratio of NanoSi to carbon dots CDs is 1:1; A method for preparing a nanocomposite material with high biological effectiveness on the surface of plant leaves, characterized in that in step (2), the rotation speed of the slow stirring is 150 rpm.

3. 1. A method for improving the biological availability of nanomaterials on the foliar surface of a plant, comprising: Step (1) of mixing aqueous ammonia, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, then adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; and (2) dissolving the obtained NanoSi in ethanol, then adding carbon dots-CDs and slowly stirring the solution until the solution evaporates, thereby obtaining a solid nanocomposite material, Nano-CDs.

4. 1. A method for preparing a nanocomposite material with high biological availability on the foliar surface of a plant, comprising: Step (1) of mixing aqueous ammonia, deionized water, ethanol, formaldehyde solution and resorcinol, stirring uniformly, then adding tetraethyl orthosilicate and stirring to obtain a mixture, then adding formaldehyde and resorcinol to the mixture, stirring to allow the mixture to react, and then centrifuging, collecting the solid, washing, drying and calcining to obtain NanoSi; and (2) dissolving the obtained NanoSi in ethanol, adding carbon dots CDs, and slowly stirring the solution until the solution evaporates to obtain a solid nanocomposite material Nano-CDs.

5. 3. The method according to claim 1 or 2, wherein in the mixture in step (1), the volume fraction of tetraethyl orthosilicate to deionized water is 6%.

6. 3. The method of claim 1 or 2, wherein in step (1), during the process of continuously adding formaldehyde and resorcinol to the mixture, the amount of resorcinol added is twice the amount of resorcinol in the mixture, and the amount of formaldehyde added is twice the amount of formaldehyde in the mixture.

7. 3. The method according to claim 1 or 2, wherein in step (2), the amount of ethanol used relative to NanoSi is 450 mL / 100 mg.

8. 3. The method according to claim 1 or 2, wherein in step (2), the mass ratio of NanoSi to carbon dots CDs is 1:

1.

9. 3. The method according to claim 1 or 2, wherein in step (2), the rotation speed of the slow stirring is 150 rpm.

10. 10. Application of the method of claim 1 to improve agricultural production.

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