Seed treatment method based on graphene composite coating and far infrared drying method

Abstract

The invention provides a seed treatment method based on a graphene composite coating and a far infrared drying method, and relates to the technical field of seed treatment. Comprising the following steps: taking carboxyl-modified graphene nanosheets, a natural polymer base material, a bioactive component and a bonding enhancer, preparing a graphene composite coating through ultrasonic dispersion, and coating seeds with the graphene composite coating on a fluidized bed to obtain coated seeds; a graphene far infrared heating film structure is prepared, the graphene far infrared heating film structure comprises a polyimide substrate layer, a graphene conductive ink printed circuit heating layer and a silica gel packaging layer, and the graphene far infrared heating film structure is used for drying the coated seeds in a far infrared gradient mode. The integrity rate of the coating layer reaches 99.5%, the graphene far-infrared heating film structure is combined and utilized to perform far-infrared gradient drying on the coated seeds, and the surface temperature standard deviation of the dried coated seeds is smaller than or equal to 1.5 DEG C.

Description

Technical Field

[0001] The present invention relates to the technical field of seed treatment, and in particular to a seed treatment method based on graphene composite coating and far-infrared drying methods. Background Art

[0002] Currently, traditional seed coatings use chemical fungicides (such as difenoconazole), but these can easily lead to soil contamination and pathogen resistance. Others use polymer coating materials (such as polyvinyl alcohol), but these are prone to thermal degradation during high-temperature drying, leading to premature and uncontrollable nutrient release. Furthermore, traditional electric drying methods experience large temperature fluctuations, up to 5°C, which can easily cause cracking in the coating or damage seed viability. Energy consumption can reach as high as 2.5 to 3.0 kWh / kg. Summary of the Invention

[0003] The problem solved by the present invention is how to solve the problems of antimicrobial resistance or uncontrollable nutrient release caused by traditional seed coating, as well as the problem of cracking of the coating layer or damage to seed activity caused by traditional electric drying.

[0004] To solve the above problems, the present invention provides a seed treatment method based on graphene composite coating and far-infrared drying method.

[0005] The present invention provides a seed treatment method based on graphene composite coating and far-infrared drying method, comprising the following steps: S1: preparing a graphene composite coating by ultrasonic dispersion of carboxyl-modified graphene nanosheets, a natural polymer substrate, a bioactive component, and an adhesion enhancer, and coating seeds with the graphene composite coating on a fluidized bed to obtain coated seeds; S2: Prepare a graphene far-infrared heating film structure, which includes a polyimide base layer, a graphene conductive ink printed circuit heating layer and a silicone encapsulation layer. Use the graphene far-infrared heating film structure to dry the coated seeds through a far-infrared gradient.

[0006] Optionally, the graphene composite coating comprises, by weight, 1 to 5 parts of carboxyl-modified graphene nanosheets, 60 to 80 parts of natural polymer substrate, 6 to 11 parts of bioactive ingredients, and 2 to 5 parts of bonding enhancer.

[0007] Optionally, the natural polymer matrix includes chitosan and starch, wherein the mass ratio of chitosan to starch is 2 to 4.

[0008] Optionally, the bioactive ingredients include 1 to 3 parts of a botanical antibacterial agent and 5 to 8 parts of trace elements by weight, the botanical antibacterial agent includes tea polyphenols or thymol, and the trace elements include zinc or boron chelate.

[0009] Optionally, the adhesion enhancer comprises polyglutamic acid.

[0010] Optionally, the carboxyl-modified graphene nanosheets have a particle size of 50 to 200 nm.

[0011] Optionally, the temperature control temperature of the gradient drying is: 40° C. for 15 to 25 minutes, 50° C. for 10 to 20 minutes, to 30° C. for 10 to 15 minutes.

[0012] Optionally, the emission wavelength of the graphene far-infrared heating film structure is 8 to 14 μm, and the power density is 0.5 to 1.2 W / cm 2 The thickness of the polyimide base layer is 50 to 100 μm, and the square resistance of the graphene conductive ink printed circuit heating layer does not exceed 10 Ω / sq.

[0013] Optionally, the air inlet temperature of the fluidized bed is 30 to 40°C.

[0014] Optionally, the graphene composite coating coated on the surface of the seeds accounts for 3% to 5% of the weight of the seeds.

[0015] The beneficial effects of the seed treatment method based on graphene composite coating and far-infrared drying of the present invention are as follows: the coating integrity rate of the seeds coated with the graphene composite coating in a fluidized bed can reach 99.5%. Combined with the use of a graphene far-infrared heating film structure for far-infrared gradient drying of the coated seeds, the standard deviation of the surface temperature of the coated seeds after drying is ≤1.5°C, which can prevent local overheating and cracking of the coating. The seed coating damage rate is less than 0.1%. After drying, the seed moisture content is stably controlled at less than 8%, with a compliance rate of 100%. The treated seeds have an antibacterial rate of 95% against Rhizoctonia solani, a 97% inhibition rate against Fusarium solani, and an inhibition rate of 89-97% against rice blast. The incidence of stem rot is reduced to less than 9%. The graphene conductive ink printed circuit has excellent conductivity, an electric heat conversion rate of ≥96%, and matches the material absorption peak in the infrared band (8-14μm). It saves 40-50% of energy, reduces the energy consumption of drying efficiency to 1.2 kWh / kg, and shortens the drying time by 30%. The germination rate of seeds increased by 25% to 35%, and the germination rate reached 98% to 105% (radicle breakthrough was enhanced). The residual content of elements in the graphene composite coating decreased from the initial 5% to 0.8% in 30 days, and the average daily release rate was stabilized at 0.14% / day, meeting the requirements of the sustained-release design. After 6 months of storage, the increase in free fatty acids in seeds treated with this method was 59.5% lower than that in the traditional group, indicating good storage stability. When a spore suspension of rice blast fungus was sprayed on the surface of the seeds, obvious physical cutting damage appeared on the surface of the pathogen hyphae, and the length of the pathogen hyphae was shortened by 60% to 72%. The graphene composite coating gives seeds antibacterial and growth-promoting functions, and the graphene far-infrared heating film structure is used to achieve precise temperature control and energy saving during the seed drying process, solving the problems of low drying efficiency, high energy consumption and high risk of heat damage of traditional coated seeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural flow chart of a seed treatment method based on graphene composite coating and far-infrared drying method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the present invention description are only for the purpose of describing specific embodiments and are not intended to limit the present invention; As used herein, the term "including" and its variations are open-ended, i.e., "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments." Definitions of other terms are provided in the following description.

[0019] In response to the problems existing in the above-mentioned related technologies, this embodiment provides a seed treatment method based on graphene composite coating and far-infrared drying method.

[0020] like Figure 1 As shown, an embodiment of the present invention provides a seed treatment method based on graphene composite coating and far-infrared drying method, comprising the following steps: S1: preparing a graphene composite coating by ultrasonic dispersion of carboxyl-modified graphene nanosheets, a natural polymer substrate, a bioactive component, and an adhesion enhancer, and coating seeds with the graphene composite coating on a fluidized bed to obtain coated seeds; S2: Prepare a graphene far-infrared heating film structure, which includes a polyimide base layer, a graphene conductive ink printed circuit heating layer and a silicone encapsulation layer. Use the graphene far-infrared heating film structure to dry the coated seeds through a far-infrared gradient.

[0021] In this embodiment, the coating layer integrity rate of the fluidized bed-coated graphene composite coating seeds reaches 99.5%. The graphene far-infrared heating film structure is combined with the far-infrared gradient drying of the coated seeds. After drying, the standard deviation of the surface temperature of the coated seeds is ≤1.5°C, which avoids cracking of the coating caused by local overheating. The seed coating breakage rate is lower than 0.1%. After drying, the moisture content of the seeds is stably controlled at less than 8%, and the compliance rate is 100%. The treated seeds have an antibacterial rate of 95% against Rhizoctonia solani, an inhibition rate of 97% against Fusarium solani, an inhibition rate of 89% to 97% for rice blast, and a stem rot incidence rate reduced to less than 9%. Graphene conductive ink printed circuits exhibit excellent conductivity, with an electrothermal conversion rate of ≥96%. The infrared wavelength (8-14 μm) matches the material's absorption peak, resulting in a 40-50% overall energy saving, reducing drying efficiency to 1.2 kWh / kg and shortening drying time by 30%. Seed germination rates increased by 25-35%, reaching 98-105% (with enhanced radicle breakthrough). The residual element content in the graphene composite coating decreased from an initial 5% to 0.8% over 30 days, with a stable daily release rate of 0.14% / day, meeting the requirements of sustained-release design. After six months of storage, the added free fatty acid content of seeds treated with this method was 59.5% lower than that of the conventional treatment, demonstrating excellent storage stability. Spraying a spore suspension of the rice blast fungus on the surface of the seeds resulted in significant physical damage to the pathogen's hyphae, shortening their length by 60-72%. Through graphene composite coating, seeds are given antibacterial and growth-promoting functions, and the graphene far-infrared heating film structure is used to achieve precise temperature control and energy saving and consumption reduction in the seed drying process, solving the problems of low efficiency, high energy consumption and high risk of heat damage in traditional coated seed drying.

[0022] Specifically, the humidity control process and equipment selection: use a condensing dehumidifier (dew point temperature ≤ -10°C) combined with a humidity sensor (accuracy ±1% RH); set up multiple humidity monitoring points (top, middle, and bottom) in the drying chamber, and provide real-time feedback to the programmable logic controller (PLC) control system.

[0023] Specifically, the seed treatment method based on graphene composite coating and far-infrared drying method includes the following steps: 1. Seed pretreatment: Soak the seeds in 0.5% to 1.0% sodium hypochlorite solution (NaClO) for 10 to 15 minutes to kill surface fungal spores and bacteria, then rinse with clean water until neutral, with residual chlorine content ≤ 0.1 ppm.

[0024] 2. Prepare a graphene composite coating solution. Carboxyl (-COOH) functional groups are introduced onto the edges and surfaces of graphene nanosheets via a redox method to produce carboxyl-modified graphene nanosheets (COOH-G). Ultrasonic dispersion of the carboxyl-modified graphene nanosheets ensures a monolayer dispersion. A natural polymer substrate (chitosan or starch) and a bonding enhancer, polyglutamic acid powder, are added. Stir in a 60°C water bath at 300 rpm for 30 minutes to form a uniform, viscous solution. Finally, the bioactive ingredients (plant growth regulators and trace elements) are added to prevent high-temperature degradation of the active ingredients. The bonding enhancer, polyglutamic acid (molecular weight 50 to 100 kDa), hydrogen bonds with the amino groups of the natural polymer substrate chitosan and the carboxyl groups of graphene, enhancing the adhesion of the coating to the seed epidermis to ≥3.5 MPa. Adding 2% polyglutamic acid increases the coating solution's viscosity from 120 mPa·s to 280 mPa·s, and the coating shedding rate, as measured by vibratory sieving, is ≤0.3%.

[0025] 3. Fluidized bed coating, the air inlet temperature is 30 to 40 ° C, and the seed coating weight gain rate is 3% to 5%.

[0026] 4. Prepare a graphene far-infrared heating film structure. The graphene far-infrared heating film structure consists of a polyimide base layer, a graphene conductive ink printed circuit heating layer, and a silicone encapsulation layer. The graphene far-infrared heating film structure is used to dry the coated seeds using a far-infrared gradient drying process. At 40°C, surface moisture is rapidly evaporated, controlling humidity to ≤25%. At 50°C, internal moisture migration is enhanced, reducing humidity to ≤15%. At 30°C, the seed moisture content is balanced to prevent rewetting, maintaining humidity at ≤10%. When the humidity exceeds the threshold, the condensing dehumidifier is activated and the air flow rate is reduced from 2.5 m / s to 1.0 m / s. Infrared thermal imaging and humidity sensors are used to monitor the surface moisture distribution of the seeds to avoid localized over-humidification. The standard deviation of the moisture content of the seeds after drying after humidity control is ≤0.3%, and the cracking rate of the coating layer is reduced from 5.2% using the traditional process to 0.1%.

[0027] Specifically, carboxyl (-COOH) functional groups were introduced into the edges and surfaces of graphene nanosheets by redox method to obtain carboxyl-modified graphene nanosheets (COOH-G) with ultra-high specific surface area (2600m 2 / g) adsorbs active substances, and the carboxyl group (-COOH) improves the hydrophilicity and interfacial binding force, significantly enhancing its interfacial binding force with the natural polymer substrate (chitosan or starch), forming a hydrogen bond network with the polymer substrate, and enhancing the mechanical strength of the coating.

[0028] Optionally, the graphene composite coating comprises, by weight, 1 to 5 parts of carboxyl-modified graphene nanosheets, 60 to 80 parts of natural polymer substrate, 6 to 11 parts of bioactive ingredients, and 2 to 5 parts of bonding enhancer.

[0029] Optionally, the natural polymer matrix includes chitosan and starch, wherein the mass ratio of chitosan to starch is 2 to 4.

[0030] In this optional embodiment, chitosan can be degraded into a film, the positive charge of chitosan promotes seed adhesion, and chitosan and COOH-G electrostatically self-assemble to form a porous sustained-release structure.

[0031] Optionally, the bioactive ingredients include 1 to 3 parts of a botanical antibacterial agent and 5 to 8 parts of trace elements by weight, the botanical antibacterial agent includes tea polyphenols or thymol, and the trace elements include zinc or boron chelate.

[0032] In this alternative embodiment, trace element zinc or boron chelates promote growth, and the bioactive ingredients synergize with the antimicrobial properties of COOH-G to protect the active ingredients. The residual zinc content in the graphene composite coating decreased from an initial 5% to 0.8% (after 30 days), and the average daily release rate remained stable at 0.14% / day, meeting the requirements of a sustained-release design.

[0033] Optionally, the adhesion enhancer comprises polyglutamic acid.

[0034] In this optional embodiment, polyglutamic acid reduces the interfacial energy, improves the adhesion between the coating layer and the seed surface, and enhances the fracture toughness of the coating.

[0035] Optionally, the carboxyl-modified graphene nanosheets have a particle size of 50 to 200 nm.

[0036] Optionally, the temperature control temperature of the gradient drying is: 40° C. 15 to 25 minutes → 50° C. 10 to 20 minutes → 30° C. 10 to 15 minutes.

[0037] Optionally, the emission wavelength of the graphene far-infrared heating film structure is 8 to 14 μm, and the power density is 0.5 to 1.2 W / cm 2 The thickness of the polyimide base layer is 50 to 100 μm, and the square resistance of the graphene conductive ink printed circuit heating layer does not exceed 10 Ω / sq.

[0038] Optionally, the air inlet temperature of the fluidized bed is 30 to 40°C.

[0039] Optionally, the graphene composite coating coated on the surface of the seeds accounts for 3% to 5% of the weight of the seeds.

[0040] The present invention is further described below with reference to specific embodiments.

[0041] Example 1, wheat seed treatment.

[0042] Graphene composite coating formula: carboxyl-modified graphene nanosheets 2%, chitosan / starch (mass ratio 3:1) 70%, tea polyphenols 2%, nano zinc oxide 5%, polyglutamic acid 3%; Graphene far-infrared heating film structural parameters: square resistance 8 Ω / sq, power density 0.8 W / cm 2 ; Far-infrared gradient drying process: 40℃ (20 min) → 50℃ (15 min) → 30℃ (10 min), total energy consumption 1.0kWh / kg.

[0043] 1. Germination rate test Method: According to ISTA (International Seed Testing Association) standards, three groups (100 seeds each) were set up: Experimental group: graphene composite coating, far-infrared gradient drying; Control group: commercially available chemical seed coating agent (12% difenoconazole), traditional electric heating film drying; Blank group: uncoated seeds.

[0044] Conditions: Constant temperature incubator (20℃±1℃, humidity 70%), 12 hours of light per day.

[0045] The germination rate test results are shown in Table 1.

[0046] Table 1 Germination rate test table of experimental group, control group and blank group

[0047] 2. Fusarium inhibition rate test Method: Inoculate spore suspension of Fusarium spores (concentration 1×10 6 CFU / mL) to the seed surface; After 14 days of greenhouse cultivation, the number of diseased seeds was counted and the inhibition rate was calculated (see Table 2).

[0048] Table 2 Inhibition rates of experimental group, control group and blank group

[0049] The surface of Fusarium hyphae in the experimental group showed large areas of damage (length was shortened by 72%), while the control group only partially inhibited it.

[0050] 3. Coating layer integrity test Method: Vibration sieving method (amplitude 3 mm, frequency 50 Hz, duration 10 min); The surface morphology of the coating layer was observed, and the coating shedding rate and integrity rate were calculated (see Table 3).

[0051] Table 3 Comparison of coating shedding rate and integrity rate of experimental group and control group

[0052] Results: The coating layer of the experimental group was continuous without cracks, and graphene was evenly embedded in the chitosan network.

[0053] Summary of results: The germination rate of the experimental group increased from 75% to 98%, the inhibition rate of Fusarium was 97%, and the coating layer integrity rate was 99.5%.

[0054] Example 2, rice seed treatment.

[0055] Graphene composite coating formula: carboxyl-modified graphene nanosheets 3%, sodium alginate / starch (mass ratio 2:1) 65%, thymol 1.5%, boric acid chelate 6%, polyglutamic acid 4%; Heating film parameters: square resistance 6 Ω / sq, power density 1.0 W / cm 2 ; Far-infrared gradient drying process: 40°C (25 min) → 50°C (10 min) → 30°C (15 min), total energy consumption 1.1 kWh / kg; Experimental group: graphene composite coating, far-infrared gradient drying; Control group: commercially available chemical seed coating agent (12% difenoconazole) and traditional electric heating film drying.

[0056] 1. Germination rate and radicle breakthrough test Methods: Salt-alkali stress conditions were set (soil EC value 8 dS / m); The time for the radicle to break through the seed coat and the final germination rate were recorded, see Table 4.

[0057] Table 4 Radicle breakthrough time and final germination rate of experimental group and control group

[0058] Among them, the germination rate >100% is due to multiple radicles or tillering.

[0059] 2. Rice blast inhibition rate test Method: Detached leaf inoculation method: spores of rice blast fungus (1×10 5 spores / mL) were inoculated into the leaves of rice seedlings; The percentage of lesion area was measured after 7 days, see Table 5.

[0060] Table 5 Table of measured lesion area percentage and inhibition rate of experimental group and control group

[0061] Molecular mechanism: qPCR detection showed that the expression level of pathogenic gene (MPG1) of the experimental group decreased by 89%.

[0062] 3. Biodegradability test of coating layer Method: Soil burial method (temperature 25℃, humidity 60%) was used to detect the degradation cycle of the coating layer. See Table 6.

[0063] Table 6 Comparison of degradation cycles of experimental group and control group

[0064] Effect: The germination rate of the experimental group increased from 80% to 105% (radicle breakthrough was enhanced), and the rice blast inhibition rate was 96%.

[0065] Example 3, corn seed treatment.

[0066] Graphene composite coating formula: carboxyl-modified graphene nanosheets 1.5%, chitosan / starch (mass ratio 4:1) 72%, tea polyphenols 2.5%, ferrous sulfate 7%, polyglutamic acid 2%; Graphene far-infrared heating film structural parameters: square resistance 10 Ω / sq, power density 0.6 W / cm 2 ; Far-infrared gradient drying process: 40℃ (15 min) → 50℃ (20 min) → 30℃ (10 min), total energy consumption 1.3kWh / kg.

[0067] Experimental group: graphene composite coating, far-infrared gradient drying; Control group: commercially available chemical seed coating agent (12% difenoconazole) and traditional electric heating film drying.

[0068] 1. Stress resistance test (drought stress) Methods: A soil moisture gradient (10%, 15%, 20%) was set; The root activity of seedlings (TTC method) and proline content were determined, see Table 7.

[0069] Table 7 Comparison of root activity and proline content of seedlings in the experimental group and the control group

[0070] 2. Stem rot inhibition rate test Methods: Inoculate stalk rot fungus ( Fusarium graminearum ) at the base of corn stalks; After 21 days, the incidence rate and disease index were calculated and shown in Table 8.

[0071] Table 8 Comparison of disease rate and disease index between experimental group and control group

[0072] 3. Mechanical properties test of coating layer Methods: The elastic modulus of the coating layer was measured by nanoindentation instrument; Simulated mechanical sowing impact test (impact energy 0.5 J), see Table 9.

[0073] Table 9 Comparison of mechanical seeding impact test between experimental group and control group

[0074] Effect: The germination rate of the experimental group increased from 82% to 99%, the stem rot inhibition rate was 94%, and the seed crack rate after drying was 0.2%.

[0075] Example 4, the energy consumption comparison table of different drying technologies is shown in Table 10.

[0076] Table 10 Comparison of energy consumption of different drying technologies

[0077] Visible far-infrared gradient drying has the lowest energy consumption, less than 1.5 kWh / kg, and comprehensive energy saving of 40%-50%.

[0078] Effect embodiment 1. Nutrient slow-release function verification experiment Materials: Graphene composite coating (carboxyl-modified graphene nanosheets 1.5%, chitosan matrix 70%, nano-zinc oxide 5%); method: Soil leaching simulation: Coated seeds were planted in simulated soil columns and irrigated continuously (50 mL / day). The leaching solution was collected and tested for nitrogen, phosphorus, and potassium release. Inductively coupled plasma optical emission spectroscopy (ICP-OES) detection: Samples were taken weekly to analyze the residual amount of trace elements in the graphene composite coating layer and calculate the sustained-release rate.

[0079] Data results: Leaching experiment: The cumulative release of nitrogen (N), phosphorus (P2O5), and potassium (K2O) in the graphene composite coating group over 30 days was reduced by 42%, 38%, and 35%, respectively, compared to the traditional coating (polyvinyl alcohol base). The sustained-release period was extended to 28 days (compared to 15 days in the traditional group). The nutrient release is shown in Table 11. Table 11 Coating nutrient release table

[0080] Element residue analysis: The residual zinc content in the graphene composite coating layer dropped from the initial 5% to 0.8% (30 days), and the average daily release rate was stabilized at 0.14% / day, meeting the sustained-release design requirements.

[0081] 2. Energy consumption ≤1.2 kWh / kg verification test Experimental design: Experimental group: graphene far-infrared heating film structure (power density 0.8 W / cm 2 , wavelength 8-14 μm); Control group: traditional electric heating film drying (power density 1.5 W / cm 2 ); method: 100 kg of corn seeds were dried (target moisture content ≤ 8%), and the energy consumption and time were recorded; An infrared temperature monitor was used to monitor the uniformity of temperature distribution. The infrared monitoring data are shown in Table 12.

[0082] Table 12 Infrared monitoring data table

[0083] Data results: Energy consumption comparison: The total energy consumption of the graphene far-infrared heating film structure is 1.1 kWh / kg, while the total energy consumption of traditional drying is 2.3 kWh / kg, with an energy saving rate of 52.2%; Drying efficiency: The drying time of the graphene far-infrared heating film structure is shortened to 2.5 hours, while the traditional drying time is 3.5 hours, and the efficiency is improved by 28.6%; Temperature uniformity: The standard deviation of the surface temperature of the coated seeds is ≤1.5℃ (±5℃ for the traditional drying group), avoiding coating cracking caused by local overheating.

[0084] 3. Disease inhibition rate verification experiment Experimental design: Pathogen inoculation: Spray the spore suspension of rice blast fungus (Magnaporthe oryzae) on the surface of rice seeds; Group processing: Experimental group: graphene composite coating (graphene 0.8%, sodium alginate matrix 65%); Control group: chemical seed dressing agent (11% S-methyl-Isopropyl ... method: After 21 days of cultivation in the greenhouse, the number of diseased plants was counted and the mycelial morphology of the pathogen was observed under a scanning electron microscope.

[0085] Data results: Rice blast inhibition rate: The incidence rate of the experimental group was 3.8%, while that of the control group was 15.2%, and the inhibition rate of the experimental group reached 96.2%; Mycelium destruction: The mycelium surface of the pathogen in the graphene composite coating group showed obvious physical cutting damage, and the mycelium length was shortened by 60%, while the control group only inhibited mycelium growth (no structural damage).

[0086] 4. Moisture content control and drying efficiency verification Experimental design: method: The moisture content of seeds was determined by the drying weight loss method; Comparison of moisture content stability between far-infrared gradient drying and hot air circulation drying (repeated 10 batches).

[0087] Data results: Moisture content control: The moisture content of seeds in the far-infrared gradient drying group was 7.2±0.3%, while that in the traditional hot air circulation drying group was 8.5±1.2%. The standard-reaching rate of the far-infrared gradient drying group was 100%; Storage stability: After 6 months of storage, the increase in free fatty acids in the far-infrared gradient drying group was 59.5% lower than that in the traditional hot air circulation drying group, and the seed germination rate in the far-infrared gradient drying group remained ≥95%.

[0088] 5. Comprehensive comparative experiment. The comparative indicators are shown in Table 13.

[0089] Table 13 Comparison of indicators based on graphene composite coating and far-infrared drying method and traditional chemical coating and hot air drying method

[0090] Table 13 shows that the seedling disease incidence rate of seeds treated with graphene composite coating and far-infrared drying method reached 0.05%, the disease incidence rate was reduced by 61.5%, the energy consumption was ≤1.2 kWh / kg, the nutrient release period was 25 to 35 days, and the rice blast inhibition rate was ≥96%.

[0091] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A seed treatment method based on graphene composite coating and far-infrared drying method, characterized in that: The following steps are involved: S1: preparing a graphene composite coating by ultrasonically dispersing carboxyl-modified graphene nanosheets, a natural polymer substrate, a bioactive component, and an adhesion enhancer, and coating seeds with the graphene composite coating on a fluidized bed to obtain coated seeds; S2: Prepare a graphene far-infrared heating film structure, which includes a polyimide base layer, a graphene conductive ink printed circuit heating layer and a silica gel encapsulation layer, and use the graphene far-infrared heating film structure to dry the coated seeds through a far-infrared gradient.

2. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 1, characterized in that: In parts by weight, the graphene composite coating comprises 1 to 5 parts of the carboxyl-modified graphene nanosheets, 60 to 80 parts of the natural polymer substrate, 6 to 11 parts of the bioactive ingredient and 2 to 5 parts of the bonding enhancer.

3. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 2, characterized in that: The natural polymer matrix comprises chitosan and starch, wherein the mass ratio of the chitosan to the starch is 2 to 4.

4. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 2, characterized in that: In parts by weight, the bioactive ingredients include 1 to 3 parts of a plant-derived antibacterial agent and 5 to 8 parts of trace elements. The plant-derived antibacterial agent includes tea polyphenols or thymol, and the trace elements include zinc or boron chelate.

5. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 2, characterized in that: The bonding enhancer includes polyglutamic acid.

6. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 2, characterized in that: The particle size of the carboxyl-modified graphene nanosheets is 50 to 200 nm.

7. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 1, characterized in that: The temperature control temperature of the gradient drying is: 40° C. for 15 to 25 minutes, 50° C. for 10 to 20 minutes, and 30° C. for 10 to 15 minutes.

8. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 1, characterized in that: The emission wavelength of the graphene far-infrared heating film structure is 8 to 14 μm, and the power density is 0.5 to 1.2 W / cm 2 The thickness of the polyimide base layer is 50 to 100 μm, and the square resistance of the graphene conductive ink printed circuit heating layer does not exceed 10 Ω / sq.

9. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 1, characterized in that: The air inlet temperature of the fluidized bed is 30 to 40°C.

10. The seed treatment method based on graphene composite coating and far-infrared drying method according to claim 1, characterized in that: The graphene composite coating coated on the surface of the seed accounts for 3% to 5% of the weight of the seed.

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