Multifunctional carbon nanomaterial capable of being used for seed treatment and preparation method of multifunctional carbon nanomaterial

Abstract

The invention belongs to the technical field of nano materials, and mainly relates to a multifunctional carbon nano material for seed treatment and a preparation method thereof. Celosia cristata seeds are taken as a main raw material and can be prepared by a hydrothermal method or a solvothermal method respectively. Aiming at the problems that an existing seed treatment reagent is complex in component, relatively high in toxicity, relatively single in function and the like, the invention provides a multifunctional carbon nanomaterial which simultaneously has the functions of promoting seed germination, preserving moisture and inhibiting bacteria. The preparation process is simple, the raw materials are cheap and easy to obtain, multiple functions are integrated, and good application prospects are achieved in the fields of agriculture, gardens, environments and the like.

Description

Technical field:

[0001] The invention belongs to the technical field of nano materials, is applicable to agriculture, environment and the like, and particularly relates to a multifunctional carbon nano material that can be used for seed treatment and a preparation method thereof. Background technology:

[0002] Seed treatment technology has been applied to a variety of crops, such as wheat, lettuce, tomatoes and sweet peppers. The treatment methods generally include coating, soaking, leaching, etc. with seed treatment reagents or materials. Common seed treatment reagents or materials include triazoles, organophosphorus, calcium chloride, etc. After treatment, these crop seeds can significantly reduce mildew, insect pests, etc., and significantly improve germination and seedling rates. However, most of the current seed treatment materials have problems such as single function and high toxicity; therefore, the development of multifunctional and low-toxic seed treatment materials has good application prospects.

[0003] With the development of science and technology, nanomaterials for seed treatment have attracted people's attention. For example, tomato seeds treated with carbon nanotubes show higher germination rate and germination potential than ordinary seeds; rapeseed seeds treated with cerium oxide nanoparticles can effectively enhance their resistance to saline-alkali environmental stress. In addition, in recent years, carbon nanomaterials have been widely studied in life sciences such as botany due to their unique physical and chemical properties. Studies have shown that carbon quantum dot materials can promote crop growth by enhancing plant photosynthesis and improving nutrient absorption efficiency. In addition, some carbon nanomaterials with novel functions have been developed one after another. For example, the team of Associate Professor Xing Xiaodong of Nanjing University of Science and Technology used folic acid as a precursor and used pyrolysis to prepare nitrogen-rich carbon nanomaterials with responsive antibacterial functions; the team of Professor Bi Hong of Anhui University and others developed carbon nanomaterials with excellent moisturizing properties, which have broad application prospects in the fields of health and home.

[0004] In this patented technology, after repeated tests and optimization of various raw materials and processes, it was found that the carbon nanomaterials prepared based on the cheap and readily available biomass raw materials - cockscomb seeds, have good moisturizing, sterilizing and growth-promoting functions: among them, the moisturizing function is conducive to the germination of seeds under stress conditions such as drought and salinity, the sterilizing function helps to prevent seeds from mildew and deterioration, and the growth-promoting effect is mainly derived from the nanomaterial's promotion of seed respiration, which is conducive to seed germination and growth. In addition, the preparation method of the carbon nanomaterial involves hydrothermal method, etc., which conforms to the principles of green chemistry and chemical engineering, and has good development prospects in production and application. Summary of the invention:

[0005] The purpose of the present invention is to provide a carbon nanomaterial that has the functions of promoting seed germination, moisturizing and inhibiting bacteria, in response to the current situation that the existing seed treatment materials have complex components, high toxicity and relatively single functions, and the raw materials and process of production are green and environmentally friendly.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a multifunctional carbon nanomaterial for seed treatment is prepared by a solvent thermal method using cockscomb seeds as a basic raw material.

[0007] A multifunctional carbon nanomaterial for seed treatment, comprising the following components:

[0008] The raw materials are configured according to the following weight percentages: cockscomb seeds are selected to account for 1% to 3%; deionized water is selected to account for 10% to 50% and 95% to 98%; anhydrous ethanol is selected to account for 0.40% to 90%.

[0009] A multifunctional carbon nanomaterial for seed treatment comprises the following steps:

[0010] (1) Celosia cristata seeds were crushed into 60-200 meshes and dispersed into a mixed solution of deionized water and anhydrous ethanol. The obtained suspension was further transferred into a polytetrafluoroethylene-lined autoclave and heated at 160-250° C. for 6-8 h.

[0011] (2) Centrifuging for 5 to 10 minutes at a rotation speed of 400 to 2000 rpm and discarding the precipitate, collecting the supernatant and freeze-drying it at -10 to -30°C to obtain cockscomb seed-based multifunctional carbon nanomaterials.

[0012] Compared with the existing technology, the present invention has many advantages and positive effects:

[0013] 1. Raw material advantages: The present invention uses cockscomb seeds as raw materials to prepare carbon nanomaterials. Plant seeds, as a biomass resource, have good environmental friendliness. In addition, cockscomb seeds are low in cost and easy to obtain, which is conducive to the large-scale production of carbon nanomaterials.

[0014] 2. Process advantages: The present invention prepares carbon nanomaterials by hydrothermal method or solvent thermal method, which is green and environmentally friendly in process flow and simple to operate.

[0015] 3. Multifunctional characteristics: The prepared carbon nanomaterials have good hygroscopic, bactericidal and growth-promoting effects. They are used in the field of seed treatment and have great advantages over existing seed treatment products. They have broad application prospects in agriculture, environment and other fields.

[0016] The main technical indicators of the carbon quantum dots prepared by the present invention are:

[0017] The carbon nanomaterials involved in the present invention have good hygroscopic effect, good bactericidal effect and good growth-promoting effect: with respect to the hygroscopic effect, in a medium humidity environment of 40%, the hygroscopic rate of the carbon nanomaterials in 48 hours is above 16%, reaching more than 50% (about 14%) of the hygroscopic rate of the commercial hygroscopic agent glycerol; with respect to the bactericidal effect, the minimum inhibitory concentration of the nanomaterials to Rhizopus nigromaculus and Staphylococcus aureus must be lower than 150 μg·mL -1 With 100 μg mL -1 . Description of the drawings:

[0018] Figure 1 Transmission electron microscope image of carbon nanomaterials

[0019] Figure 2 Moisture absorption curve of carbon nanomaterials in 40% humidity environment Specific implementation method:

[0020] The specific implementation method is described in detail below.

[0021] A multifunctional carbon nanomaterial that can be used for seed treatment uses cockscomb seeds as a basic raw material and is prepared through a solvothermal method.

[0022] The preparation method of the multifunctional carbon nanomaterial that can be used for seed treatment comprises the following raw material components:

[0023] The raw materials are configured according to the following weight percentages: cockscomb seeds are selected to account for 1% to 3%; deionized water is selected to account for 10% to 50% and 95% to 98%; anhydrous ethanol is selected to account for 0.40% to 90%.

[0024] When deionized water is used, the proportion is 95% to 98%, and anhydrous ethanol is used, the proportion is 0, and the method is a hydrothermal method.

[0025] a. Hydrothermal method:

[0026] The raw materials are configured according to the following weight percentages: 1% to 3% cockscomb seeds; 95% to 98% deionized water. The cockscomb seeds are crushed to 60 to 200 mesh and dispersed in deionized water. The resulting suspension is further transferred to a polytetrafluoroethylene-lined autoclave and heated at 160 to 250°C for 6 to 8 hours to obtain a suspension of a crude product. Subsequently, centrifuge for 5 to 10 minutes at a speed of 400 to 2000 rpm and discard the precipitate. The supernatant is collected and freeze-dried at -10 to -30°C to obtain cockscomb seed-based multifunctional carbon nanomaterials. The prepared carbon nanomaterials are sampled and observed with the aid of a transmission electron microscope. It can be seen that the prepared nanomaterials are spherical structures with a diameter of 4 to 8 nanometers (see Figure 1); then, at a constant temperature of 25°C, glycerol (commercial moisturizer) and carbon nanomaterials were placed in a constant humidity environment of 40±2 to compare the moisture absorption and moisture retention capabilities of the two samples. Finally, the sand culture method was used to examine the effect of carbon nanomaterials on seed germination, with a concentration of 0.01-0.03 mg·mL -1 After wetting the fine sand with the carbon nanomaterial solution, plant seeds were shallowly buried under the fine sand. The fine sand was sprayed with the carbon nanomaterial solution once in the morning and evening every day. Distilled water was used as the comparative culture medium, and the effect of the carbon nanomaterial on seed germination was observed for 5 to 7 days.

[0027] b. Solvothermal method:

[0028] The raw materials are configured according to the following weight percentages: Cockscomb seeds are selected, accounting for 1% to 3%; deionized water is selected, accounting for 10% to 50%; anhydrous ethanol is selected, accounting for 40% to 90%. The cockscomb seeds are crushed to 60 to 200 meshes with a grinder, dispersed in a mixed solution of deionized water and anhydrous ethanol, and the resulting suspension is further transferred to a polytetrafluoroethylene-lined autoclave and heated at 160 to 250°C for 6 to 8 hours. Under the condition of a speed of 400 to 2000rpm, centrifuge for 5 to 10 minutes and discard the precipitate, collect the supernatant and freeze-dry at -10 to -30°C, and collect the cockscomb seed-based multifunctional carbon nanomaterial. The prepared carbon nanomaterials are then tested for micromorphology, moisture retention, and germination promotion ability.

[0029] Embodiment 1:

[0030] Take 5g of cockscomb seeds and 500mL of deionized water respectively. Grind the cockscomb seeds to 120 mesh, mix with deionized water, and then transfer to an autoclave for thorough stirring and dispersion. Place the autoclave in an oven, heat to 200°C, react for 6 hours, let stand and cool, centrifuge at 5000rpm for 5min, and take the supernatant. Freeze-dry the supernatant at -15°C to obtain a multifunctional carbon nanomaterial with seed germination promotion, moisturizing, and antibacterial effects.

[0031] The results showed that the moisture absorption rate of the prepared carbon nanomaterials was 21.6% at 25°C and 42% humidity in 48 hours, which was higher than the half value of the moisture absorption rate of commercial humectant glycerol (14.6%). The minimum inhibitory concentration of carbon nanomaterials against Rhizopus nigricans and Staphylococcus aureus was 120 μg·mL -1 With 80μg·mL -1 The culture medium (0.02 mg·mL) prepared with the nanomaterial -1) The root length of cotton seedlings cultured in sand cultured cotton seeds increased by an average of about 25.4% after 5 days compared with the seedlings cultured in blank distilled water group; the wet weight of cotton seedlings cultured using carbon nanomaterials increased by an average of about 26.8% compared with the blank group; the wet weight of cotton seedlings cultured using carbon nanomaterials increased by an average of about 34.2% compared with the blank group.

[0032] Embodiment 2:

[0033] Take 2.0g of cockscomb seeds, 120mL of distilled water, and 30mL of ethanol respectively. Grind the cockscomb seeds to 150 mesh, mix with distilled water and ethanol, and then transfer to an autoclave for thorough stirring and dispersion. Heat to 220℃, react for 8 hours, let stand and cool, centrifuge at 600rpm for 6min, discard the precipitate, and take the supernatant. Freeze-dry at -10℃ to obtain a carbon nanomaterial with seed germination promotion, moisturizing, and antibacterial effects.

[0034] It was determined that at 25°C, the moisture absorption rate of the prepared carbon nanomaterial reached 20.9% after 48 hours; the minimum inhibitory concentration of the carbon nanomaterial against Rhizopus nigromaculata was 130 μg·mL -1 The culture medium (0.02 mg·mL) prepared with the nanomaterial -1 ) The root length of corn sprouts cultured in sand cultured corn seeds after 6 days increased by an average of about 22.8% compared with the sprouts cultured in the blank distilled water group; the wet weight of corn sprouts cultured using carbon nanomaterials increased by an average of about 30.4% compared with the blank group.

[0035] Embodiment 3:

[0036] Take 1.8g of cockscomb seeds, 100mL of distilled water, and 40mL of anhydrous ethanol respectively. Grind the cockscomb seeds to 180 mesh, mix with distilled water and ethanol, and then transfer to an autoclave for full stirring and dispersion. Heat to 250℃, react for 6 hours, centrifuge at 550rpm for 6min, discard the precipitate, and take the supernatant. Freeze-dry at -20℃ to obtain a carbon nanomaterial with seed germination promotion, moisturizing, and antibacterial effects.

[0037] It was determined that at 25°C, the moisture absorption rate of the prepared carbon nanomaterial could reach 20.8% after 48 hours, and the minimum inhibitory concentration against Staphylococcus aureus was 100 μg·mL -1 The culture medium (0.03 mg·mL) prepared with the nanomaterial -1 ) The root length of cotton seedlings cultured in sand culture for 5 days increased by an average of about 18.7% compared with the seedlings cultured in the blank distilled water group; the wet weight of cotton seedlings cultured using carbon nanomaterials increased by an average of about 27.2% compared with the blank group.

[0038] The present invention uses cheap and readily available cockscomb seeds as the basic raw material, and aims to prepare multifunctional carbon nanomaterials with seed germination promotion, moisture retention and antibacterial properties by using a hydrothermal method or a solvothermal method. Among them, biomass resources have the advantages of being renewable and abundant in reserves compared to mineral raw materials. This patented technology proposes cheap and readily available cockscomb seeds as raw materials on the premise of optimizing a variety of biomass resources, which conforms to the concept of sustainable development; the hydrothermal method or the solvent method is used as the reaction path, and water or ethanol is selected as the reagent to avoid the introduction of highly toxic substances; the prepared nanomaterials have multiple effects of moisture retention, antibacterial, and seed germination promotion, achieving multiple goals at one stroke, and as nano seed treatment materials, they have broad application prospects in agriculture, environment and other fields.

[0039] In addition, the above description is not a limitation of the present invention. All changes, modifications and substitutions made within the essential scope of the present invention belong to the protection scope of the invention.

Claims

1. A multifunctional carbon nanomaterial that can be used for seed treatment, characterized in that: Celosia cristata seeds were used as the basic raw materials and Celosia cristata seeds-based carbon nanomaterials were prepared by solvothermal method.

2. A method for preparing a multifunctional carbon nanomaterial that can be used for seed treatment according to claim 1, characterized in that: The raw material components are as follows: The raw materials are configured according to the following weight percentages: cockscomb seeds are selected to account for 1% to 3%; deionized water is selected to account for 10% to 50% and 95% to 98%; anhydrous ethanol is selected to account for 0.40% to 90%.

3. A method for preparing a multifunctional carbon nanomaterial that can be used for seed treatment according to claim 2, characterized in that: The following steps are involved: (1) Celosia cristata seeds were crushed into 60-200 meshes and dispersed into a mixed solution of deionized water and anhydrous ethanol. The obtained suspension was further transferred into a polytetrafluoroethylene-lined autoclave and heated at 160-250° C. for 6-8 h. (2) Centrifuging for 5 to 10 min at a rotation speed of 400 to 2000 rpm and discarding the precipitate, freeze-drying the supernatant at -10 to -30°C, and collecting the cockscomb seed-based multifunctional carbon nanomaterial.

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