Coated slow-release insect-resistant organic fertilizer and preparation method thereof

Abstract

The invention discloses a coated slow-release insect-resistant organic fertilizer and a preparation method thereof, and relates to the technical field of fertilizers. Citric acid is used as a cross-linking agent to prepare sulfydryl cellulose hydrogel, citric acid can enable the fertilizer to have an insect-resistant effect, then a Fe-MOFs metal framework material and epoxy resin are added into the cellulose hydrogel, and ultraviolet light is utilized to promote a click reaction of sulfydryl and epoxy group to form an interpenetrating network, so that the cross-linking effect of the Fe-MOFs metal framework material and the epoxy resin is improved, and the cross-linking effect of the Fe-MOFs metal framework material is improved. The mechanical property and stability of the coating material can be further improved, so that the coating material is more durable, and the utilization rate of the organic fertilizer is increased; secondly, under the assistance of a magnetic field, a coating material is sprayed on organic fertilizer particles in an ultrasonic atomization mode, and the coated slow-release insect-resistant organic fertilizer is prepared; a magnetic field is applied, so that the Fe-MOFs metal framework material in the coating material has magnetism, the utilization rate of the organic fertilizer can be effectively increased through the soil magnetic effect and the biological magnetic effect, and the soil environment can be improved. The coated slow-release insect-resistant organic fertilizer prepared by the invention has the effects of durability and high efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizers, in particular to a coated slow-release insect-resistant organic fertilizer and a preparation method thereof. Background Art

[0002] With the increasing demand for food and various green crops, it is very important to increase crop yields by various means. In addition to cultivating new crops, increasing the nutrients necessary for crop growth is an alternative method that can be efficiently provided by chemical fertilizers. Although the use of fertilizers has a history of more than 140 years, traditional fertilizers have serious nutrient loss problems when used on cultivated land. On average, about 90% of the applied fertilizers are lost to the environment due to high leaching or instantaneous release caused by high solubility, and volatilization losses of N. At present, there are various mitigation measures for environmental pollution and utilization rate of fertilizers, such as the use of different fertilizer formulas and methods, the application of nitrification inhibitors, etc.

[0003] As a new strategy to improve fertilizer utilization by designing fertilizer structure, slow-release fertilizer is gaining more and more attention. Slow-release fertilizer is to control the release of fertilizer by introducing slow-release preparations, prolong the release time of fertilizer, make it release gradually, keep pace with the needs of plants, and thus improve the utilization rate of fertilizer by plants. More importantly, it reduces soil degradation, eutrophication of water bodies and other environmental pollution to meet the trend of stricter environmental protection.

[0004] Therefore, the present invention provides a coated slow-release insect-resistant organic fertilizer and a preparation method thereof to achieve durable and efficient effects. Summary of the invention

[0005] The object of the present invention is to provide a coated slow-release insect-resistant organic fertilizer and a preparation method thereof, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a coated slow-release insect-resistant organic fertilizer, wherein the coated slow-release insect-resistant organic fertilizer is prepared by adding Fe-MOFs metal skeleton material and epoxy resin to cellulose hydrogel to obtain a coating material, and then ultrasonically atomizing and spraying the coating material on organic fertilizer particles with the assistance of a magnetic field.

[0007] Furthermore, the coating material is prepared by adding Fe-MOFs metal skeleton material and epoxy resin into cellulose hydrogel and then irradiating with ultraviolet light.

[0008] Furthermore, the Fe-MOFs metal skeleton material includes one or more of Fe-BDC, Fe-2MI and Fe-BDC / Fe-2MI.

[0009] Furthermore, the cellulose hydrogel is prepared by first introducing thiol groups into cellulose and then using citric acid as a cross-linking agent.

[0010] Furthermore, the organic fertilizer granules are obtained by harmlessly treating human and animal feces through EM composting method, and then extruding the materials through a twin-screw extruder to form granules.

[0011] Furthermore, a method for preparing a coated slow-release insect-resistant organic fertilizer comprises the following preparation steps:

[0012] (1) The hydrophobic cellulose and ammonium persulfate are mixed at a mass ratio of 1:1 to 1.5 to obtain a mixture, which is dissolved in deionized water 12 to 13 times the mass of the mixture, and ultrasonically dispersed at 30 to 40 kHz for 30 to 60 minutes at 25° C., butenoic acid, butenol, citric acid and hydrophobic cellulose are added to the mixture at a mass ratio of 0.4 to 0.5:0.5 to 0.6:0.05 to 0.2:1, and reacted at 70 to 80° C. for 2 to 3 hours, and the solid was filtered to obtain a solid, washed with water until neutral, and dried at room temperature for 2 to 3 hours to obtain a cellulose hydrogel;

[0013] (2) Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel are mixed in a mass ratio of 0.1-0.3:0.5-0.6:1, ultrasonically dispersed at 30-40kHz for 1-2h, heated to 70-80°C, reacted for 2-3h, added with 9-10 times the mass of cellulose hydrogel and 0.5 mol / L acetate buffer solution with a pH of 3.6, stirred at 300-400 r / min for 30-40min, added with 0.05-0.1 times the mass of cellulose hydrogel and water-soluble photoinitiator, ultrasonically dispersed at 40-50kHz for 1-1.5h, and irradiated under ultraviolet light for 30-60min to obtain a coating material;

[0014] (3) The coating material is placed in an ultrasonic atomizer, and a stable magnetic field with a strength of 0.50 T is applied to assist in spraying the coating material onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer.

[0015] Furthermore, the preparation method of the hydrophobic cellulose in step (1) is as follows:

[0016] a. Mix 13.5wt% sodium hydroxide solution and α-cellulose in a mass ratio of 25-30:1, heat to 60°C, stir at 200-300r / min for 4-6h, add ethanol 0.5-0.8 times the mass of the sodium hydroxide solution, filter and take the filter cake, wash the filter cake with water until the pH of the suspension is neutral, place the suspension in a freeze dryer at a temperature of -35°C and a pressure of 25Pa for freeze drying for 20-24h to obtain alkalized cellulose, repeat the above operation until filtration, obtain a new filter cake after filtration, place the new filter cake in a vacuum drying oven at 50-60°C and 50kPa for drying for 7-8h, grind into powder to obtain alkalized cellulose;

[0017] b. Dry the alkalized cellulose at 100°C for 16 to 30 minutes, mix it with glycidyl methacrylate and dioxane at a molar ratio of 1:5 to 6:5 to 6, heat it to 70 to 80°C, heat it for 6 to 8 hours, then heat it to 120 to 125°C, heat it for 2 to 2.5 hours, wash it with tetrahydrofuran solution for 4 to 5 times, and dry it in a vacuum drying oven at 20 to 30°C and 50 kPa for 10 to 12 hours to obtain modified cellulose;

[0018] c. Expel the air in the reaction device with nitrogen, mix the modified cellulose and tetrahydrofuran in a mass ratio of 1:3-5, disperse them by ultrasonic at 30-40kHz for 10-15min, introduce hydrogen sulfide gas at a flow rate of 0.5-0.8L / min until the reaction is completed, react at 45-50℃ for 1.8-2d, place in ethanol, wash with ultrasonic at 30-40kHz for 5-6 times, and then place in a vacuum drying oven at 20-30℃, 50kPa for 3-3.5d to obtain hydrophobic cellulose.

[0019] Furthermore, the preparation method of the water-soluble photoinitiator in step (2) is: adding 0.6-0.8g of DBU reagent to 10ml of ether solution dissolved with 1-2g of ketoprofen, stirring at 200-300r / min for 60-70min, filtering to obtain the solid, washing with ether solvent for 3-5 times, and drying under reduced pressure to obtain the solid.

[0020] Furthermore, the ultraviolet light irradiation condition in step (2) is to use a light intensity of 20 mW / cm 2 Irradiation with 365nm ultraviolet light.

[0021] Furthermore, the conditions for ultrasonic atomization spraying in step (3) are as follows: a liquid inlet rate of 10 mL / h into the nozzle, an ultrasonic generator frequency of 44 kHz, a power of 2.5 W, and high-purity argon gas as a carrier gas with a flow rate of 3 L / min.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0023] The present invention adds Fe-MOFs metal skeleton material and epoxy resin into cellulose hydrogel to prepare coating material, and then ultrasonically atomizes and sprays the coating material onto organic fertilizer particles with the assistance of a magnetic field to prepare coated slow-release insect-resistant organic fertilizer, so as to achieve durable and efficient effects.

[0024] First, citric acid is used as a cross-linking agent to prepare a thiocyanate-modified cellulose hydrogel. The addition of citric acid can make the fertilizer anti-insect. Then, Fe-MOFs metal skeleton material and epoxy resin are added to the cellulose hydrogel, and ultraviolet light is used to induce a click reaction between the thiocyanate and the epoxy group to form an interpenetrating network, which can further improve the mechanical properties and stability of the coating material and make the coating material more durable. At the same time, due to the pore characteristics and chemical stability of the Fe-MOFs metal skeleton material, its addition can improve the mechanical properties and water retention properties of the coating material and improve the utilization rate of organic fertilizers.

[0025] Secondly, with the assistance of a magnetic field, the coating material is ultrasonically atomized and sprayed on the organic fertilizer particles to produce a coated slow-release insect-resistant organic fertilizer; a magnetic field is applied to make the Fe-MOFs metal skeleton material in the coating material magnetic, which can effectively improve the utilization rate of organic fertilizer through soil magnetic effect and biomagnetic effect, and can also improve the soil environment; ultrasonic atomization spraying can make the coating material more evenly and tightly coated on the surface of the organic fertilizer, thereby improving the utilization rate of the coating material. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various index testing methods of the coated slow-release insect-resistant organic fertilizer prepared in the following examples are as follows:

[0028] Durability: The coated slow-release insect-resistant organic fertilizers of the same mass prepared in the embodiment and the comparative example were subjected to nutrient extraction according to the method of GB / T23348-2009 "Slow-release fertilizers". The treated fertilizers were added to 200 ml of water, sealed, and placed in a biochemical constant temperature incubator at 25°C. The dissolution rates of nitrogen and potassium in the fertilizers were detected and recorded according to the sampling time.

[0029] High efficiency: Spread the same mass of the coated slow-release insect-resistant organic fertilizers prepared in the embodiment and the comparative example into a 5m 2All fertilizers were applied at once on the experimental land, the soil was deep-turned to about 20 cm, and mechanical sowing was performed to compare the wheat yield. The conventional management of the wheat field was the same as that of the conventional one. Chemical weeding, insect control, reasonable irrigation, and sufficient water were used.

[0030] Example 1

[0031] A method for preparing a coated slow-release insect-resistant organic fertilizer comprises the following preparation steps:

[0032] (1) 13.5 wt% sodium hydroxide solution and α-cellulose are mixed in a mass ratio of 25:1, the temperature is raised to 60°C, stirred at 200 r / min for 4 hours, ethanol 0.5 times the mass of the sodium hydroxide solution is added, and the filter cake is filtered out by suction. The filter cake is washed with water until the pH of the suspension is neutral, and the suspension is placed in a freeze dryer for freeze drying at a temperature of -35°C and a pressure of 25 Pa for 20 hours to obtain alkalized cellulose, and the above operation is repeated until filtration is completed, and a new filter cake is obtained after filtration. The new filter cake is placed in a vacuum drying oven and dried at 50°C and 50 kPa for 7 hours, and ground into powder to obtain alkalized cellulose;

[0033] (2) drying the alkalized cellulose at 100° C. for 16 min, mixing with glycidyl methacrylate and dioxane at a molar ratio of 1:5:5, heating to 70° C. for 6 h, then heating to 120° C. for 2 h, washing with tetrahydrofuran solution for 4 times, and drying in a vacuum drying oven at 20° C. and 50 kPa for 10 h to obtain modified cellulose;

[0034] (3) Expelling air from the reaction device with nitrogen, mixing modified cellulose and tetrahydrofuran at a mass ratio of 1:3, dispersing them by ultrasonic wave at 30kHz for 10 minutes, introducing hydrogen sulfide gas at a flow rate of 0.5L / min until the reaction is completed, reacting at 45°C for 1.8 days, placing in ethanol, washing by ultrasonic wave at 30kHz for 5 times, and then drying in a vacuum drying oven at 20°C and 50kPa for 3 days to obtain hydrophobic cellulose;

[0035] (4) The hydrophobic cellulose and ammonium persulfate are mixed in a mass ratio of 1:1 to obtain a mixture, which is dissolved in deionized water 12 times the mass of the mixture, and dispersed at 30kHz ultrasonic wave at 25°C for 30 to 60 minutes, and butenoic acid, butenol, citric acid and hydrophobic cellulose are added to the mixture in a mass ratio of 0.4:0.5:0.05:1, and reacted at 70°C for 2 hours. The solid is filtered to obtain a solid, washed with water until neutral, and dried at room temperature for 2 hours to obtain a cellulose hydrogel;

[0036] (5) adding 0.6 g of DBU reagent to 10 ml of ether solution containing 1 g of ketoprofen, stirring at 200 r / min for 60 min, filtering out the solid, washing it with ether solvent for 3 times, and drying the solid under reduced pressure to obtain a water-soluble photoinitiator;

[0037] (6) Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel were mixed in a mass ratio of 0.1:0.5:1, dispersed by 30kHz ultrasonic wave for 1 hour, heated to 70°C, reacted for 2 hours, added with 9 times the mass of cellulose hydrogel, 0.5 mol / L acetate buffer solution with a pH of 3.6, stirred at 300 r / min for 30 minutes, added with 0.05 times the mass of cellulose hydrogel, water-soluble photoinitiator, dispersed by 40kHz ultrasonic wave for 1 hour, and irradiated with 365nm ultraviolet light with a light intensity of 20mW / cm2 for 30 minutes to obtain the coating material;

[0038] (7) The coating material is placed in an ultrasonic atomizer, the liquid inlet rate of the nozzle is 10 mL / h, the frequency of the ultrasonic generator is 44 kHz, the power is 2.5 W, and the flow rate of high-purity argon is 3 L / min as the carrier gas. A stable magnetic field with an intensity of 0.50 T is applied to assist in spraying onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer.

[0039] Example 2

[0040] A method for preparing a coated slow-release insect-resistant organic fertilizer comprises the following preparation steps:

[0041] (1) 13.5 wt% sodium hydroxide solution and α-cellulose are mixed in a mass ratio of 28:1, the temperature is raised to 60°C, stirred at 250 r / min for 5 h, 0.7 times the mass of ethanol of the sodium hydroxide solution is added, and the filter cake is filtered out by suction, the filter cake is washed with water until the pH of the suspension is neutral, the suspension is placed in a freeze dryer at a temperature of -35°C and a pressure of 25 Pa for freeze drying for 22 h to obtain alkalized cellulose, the above operation is repeated again until filtration is completed, and a new filter cake is obtained after filtration, the new filter cake is placed in a vacuum drying oven at 55°C and 50 kPa for drying for 7 h, and ground into powder to obtain alkalized cellulose;

[0042] (2) drying the alkalized cellulose at 100° C. for 16 to 30 minutes, mixing with glycidyl methacrylate and dioxane at a molar ratio of 1:5:6, heating to 75° C. for 7 hours, then heating to 122° C. for 2 hours, washing with tetrahydrofuran solution for 4 times, and drying in a vacuum drying oven at 25° C. and 50 kPa for 11 hours to obtain modified cellulose;

[0043] (3) Expelling air from the reaction apparatus with nitrogen, mixing modified cellulose and tetrahydrofuran at a mass ratio of 1:4, dispersing by ultrasonic wave at 35 kHz for 13 min, introducing hydrogen sulfide gas at a flow rate of 0.7 L / min until the reaction is completed, reacting at 48° C. for 1.9 d, placing in ethanol, washing by ultrasonic wave at 35 kHz for 5 times, and then drying in a vacuum drying oven at 25° C. and 50 kPa for 3.3 d to obtain hydrophobic cellulose;

[0044] (4) The hydrophobic cellulose and ammonium persulfate were mixed at a mass ratio of 1:1.3 to obtain a mixture, which was dissolved in deionized water 12 times the mass of the mixture, and ultrasonically dispersed at 35kHz for 45 minutes at 25°C, and butenoic acid, butenol, citric acid and hydrophobic cellulose were added to the mixture at a mass ratio of 0.4:0.5:0.1:1, and reacted at 75°C for 2 hours. The solid was filtered, washed with water until neutral, and dried at room temperature for 2 hours to obtain a cellulose hydrogel;

[0045] (5) adding 0.7 g of DBU reagent to 10 ml of ether solution containing 1.5 g of ketoprofen, stirring at 250 r / min for 65 min, filtering out the solid, washing it with ether solvent for 4 times, and drying the solid under reduced pressure to obtain a water-soluble photoinitiator;

[0046] (6) Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel were mixed in a mass ratio of 0.2:0.5:1, dispersed by 35kHz ultrasonic wave for 1-2h, heated to 75°C, reacted for 2h, added with 0.5mol / L acetate buffer solution with a pH of 3.6 (9 times the mass of cellulose hydrogel), stirred at 350r / min for 35min, added with 0.08 times the mass of cellulose hydrogel water-soluble photoinitiator, dispersed by 45kHz ultrasonic wave for 1-1.3h, and irradiated with 365nm ultraviolet light with a light intensity of 20mW / cm2 for 45min to obtain the coating material;

[0047] (7) The coating material is placed in an ultrasonic atomizer, the liquid inlet rate of the nozzle is 10 mL / h, the frequency of the ultrasonic generator is 44 kHz, the power is 2.5 W, and the flow rate of high-purity argon is 3 L / min as the carrier gas. A stable magnetic field with an intensity of 0.50 T is applied to assist in spraying onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer.

[0048] Example 3

[0049] A method for preparing a coated slow-release insect-resistant organic fertilizer comprises the following preparation steps:

[0050] (1) 13.5 wt% sodium hydroxide solution and α-cellulose are mixed in a mass ratio of 30:1, the temperature is raised to 60°C, and the mixture is stirred at 300 r / min for 6 hours. Ethanol in an amount of 0.8 times the mass of the sodium hydroxide solution is added, and a filter cake is obtained by suction filtration. The filter cake is washed with water until the pH of the suspension is neutral. The suspension is placed in a freeze dryer and freeze-dried for 24 hours at a temperature of -35°C and a pressure of 25 Pa to obtain alkalized cellulose. The above operation is repeated until suction filtration is performed. After suction filtration, a new filter cake is obtained. The new filter cake is placed in a vacuum drying oven and dried at 60°C and 50 kPa for 8 hours, and ground into powder to obtain alkalized cellulose.

[0051] (2) drying the alkalized cellulose at 100° C. for 30 min, mixing with glycidyl methacrylate and dioxane at a molar ratio of 1:6:6, heating to 80° C. for 8 h, then heating to 125° C. for 2.5 h, washing with tetrahydrofuran solution for 5 times, and drying in a vacuum drying oven at 30° C. and 50 kPa for 12 h to obtain modified cellulose;

[0052] (3) Expelling air from the reaction device with nitrogen, mixing modified cellulose and tetrahydrofuran at a mass ratio of 1:5, dispersing them by ultrasonic wave at 40kHz for 15min, introducing hydrogen sulfide gas at a flow rate of 0.8L / min until the reaction is completed, reacting at 50°C for 2d, placing in ethanol, washing by ultrasonic wave at 40kHz for 6 times, and then drying in a vacuum drying oven at 30°C and 50kPa for 3.5d to obtain hydrophobic cellulose;

[0053] (4) The hydrophobic cellulose and ammonium persulfate were mixed at a mass ratio of 1:1.5 to obtain a mixture, which was dissolved in deionized water 13 times the mass of the mixture, and dispersed at 40kHz ultrasonic wave at 25°C for 60 minutes. Cetyl alcohol, butenol, citric acid and hydrophobic cellulose were added to the mixture at a mass ratio of 0.5:0.6:0.2:1, and reacted at 80°C for 3 hours. The solid was filtered to obtain a solid, washed with water until neutral, and dried at room temperature for 3 hours to obtain a cellulose hydrogel;

[0054] (5) adding 0.8 g of DBU reagent to 10 ml of ether solution containing 2 g of ketoprofen, stirring at 300 r / min for 70 min, filtering out the solid, washing it with ether solvent for 5 times, and drying the solid under reduced pressure to obtain a water-soluble photoinitiator;

[0055] (6) Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel were mixed in a mass ratio of 0.3:0.6:1, dispersed by 40kHz ultrasonic wave for 2h, heated to 80°C, reacted for 3h, added with 10 times the mass of cellulose hydrogel, 0.5 mol / L acetate buffer solution with a pH of 3.6, stirred at 400r / min for 40min, added with 0.1 times the mass of cellulose hydrogel, water-soluble photoinitiator, dispersed by 50kHz ultrasonic wave for 1.5h, and irradiated with 365nm ultraviolet light with a light intensity of 20mW / cm2 for 60min to obtain the coating material;

[0056] (7) The coating material is placed in an ultrasonic atomizer, the liquid inlet rate of the nozzle is 10 mL / h, the frequency of the ultrasonic generator is 44 kHz, the power is 2.5 W, and the flow rate of high-purity argon is 3 L / min as the carrier gas. A stable magnetic field with an intensity of 0.50 T is applied to assist in spraying onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer.

[0057] Comparative Example 1

[0058] The difference between Comparative Example 1 and Example 2 is that step (6) is different. Step (6) is changed to: E-44 epoxy resin and cellulose hydrogel are mixed in a mass ratio of 0.5:1, ultrasonically dispersed at 35kHz for 1 to 2 hours, heated to 75°C, reacted for 2 hours, added with an acetate buffer solution of 0.5 mol / L and pH 3.6 in an amount of 9 times the mass of the cellulose hydrogel, stirred at 350 r / min for 35 minutes, added with a water-soluble photoinitiator in an amount of 0.08 times the mass of the cellulose hydrogel, ultrasonically dispersed at 45kHz for 1 to 1.3 hours, and irradiated with a 365nm ultraviolet lamp with a light intensity of 20 mW / cm2 for 45 minutes to obtain a coating material; the remaining steps are the same as those in Example 2.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 2 lies in step (6). Step (6) is changed to: the Fe-MOFs metal skeleton material and the cellulose hydrogel are mixed in a mass ratio of 0.2:1, ultrasonically dispersed at 35kHz for 1 to 2 hours, heated to 75°C, reacted for 2 hours, added with an acetate buffer solution of 0.5 mol / L and a pH of 3.6 in an amount of 9 times the mass of the cellulose hydrogel, stirred at 350 r / min for 35 minutes, added with a water-soluble photoinitiator in an amount of 0.08 times the mass of the cellulose hydrogel, ultrasonically dispersed at 45kHz for 1 to 1.3 hours, and irradiated with a 365nm ultraviolet lamp with a light intensity of 20 mW / cm2 for 45 minutes to obtain a coating material; the remaining steps are the same as those in Example 2.

[0061] Comparative Example 3

[0062] The difference between Comparative Example 3 and Example 2 is that there is no step (5), and step (6) is changed to: Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel are mixed in a mass ratio of 0.2:0.5:1, dispersed at 35kHz ultrasonic wave for 1 to 2h, heated to 75°C, reacted for 2h, added with acetate buffer solution with a concentration of 0.5mol / L and pH of 3.6 in an amount of 9 times the mass of cellulose hydrogel, and stirred at 350r / min for 35min to obtain a coating material; the remaining steps are the same as those in Example 2.

[0063] Comparative Example 4

[0064] The difference between Comparative Example 4 and Example 2 is that step (7) is different. Step (7) is changed to: placing the coating material in an ultrasonic atomizer, the nozzle liquid inlet rate is 10 mL / h, the ultrasonic generator frequency is 44kHz, the power is 2.5W, and high-purity argon with a flow rate of 3L / min is used as a carrier gas, and sprayed onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer; the remaining steps are the same as in Example 2.

[0065] Effect example

[0066] The following table shows the performance analysis results of the coated slow-release insect-resistant organic fertilizers of Examples 1 to 3 of the present invention and Comparative Examples 1 to 4.

[0067] Table 1 Dissolution rate of leaching time of Examples 1-3 and Comparative Examples 1 to 4

[0068] Dissolution rate (%) 5d 10d 15d 20d 25d 30d 35d Example 1 5 12 19 25 35 53 72 Example 2 5 11 17 / 24 34 51 69 Example 3 5 13 20 27 38 54 74 Comparative Example 1 7 16 21 31 46 64 83 Comparative Example 2 8 17 23 34 48 67 89 Comparative Example 3 7 16 22 33 48 66 87 Comparative Example 4 5 12 18 26 37 56 73

[0069] Table 2 Comparative experimental results of wheat fertilization of Examples 1-3 and Comparative Examples 1 to 4

[0070] deal with <![CDATA[Average yield (kg / m 2 )]]> Yield increase rate (%) No fertilizer 0.45 0 Example 1 0.9 76 Example 2 0.81 80 Example 3 0.80 78 Comparative Example 1 0.69 53 Comparative Example 2 0.75 67 Comparative Example 3 0.72 60 Comparative Example 4 0.70 56

[0071] From the comparison of the experimental data of the embodiment and the comparative example, it can be found that the present invention adds Fe-MOFs metal skeleton material and epoxy resin to cellulose hydrogel, and uses ultraviolet light to promote the click reaction between the thiol group and the epoxy group to form an interpenetrating network, which can further improve the mechanical properties and stability of the coating material, making the coating material more durable. At the same time, due to the pore characteristics and chemical stability of the Fe-MOFs metal skeleton material, its addition can improve the mechanical properties and water retention properties of the coating material and improve the utilization rate of organic fertilizers; with the assistance of a magnetic field, the coating material is ultrasonically atomized and sprayed on organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer; a magnetic field is applied to make the Fe-MOFs metal skeleton material in the coating material magnetic, which can effectively improve the utilization rate of organic fertilizers through soil magnetic effects and biomagnetic effects, and can also improve the soil environment; ultrasonic atomization spraying can make the coating material more evenly and tightly coated on the surface of the organic fertilizer, thereby improving the utilization rate of the coating material.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A coated slow-release insect-resistant organic fertilizer, characterized in that: The coated slow-release insect-resistant organic fertilizer is prepared by adding Fe-MOFs metal skeleton material and epoxy resin into cellulose hydrogel to obtain a coating material, and then ultrasonically atomizing and spraying the coating material on organic fertilizer particles with the assistance of a magnetic field.

2. The coated slow-release insect-resistant organic fertilizer according to claim 1, characterized in that: The coating material is prepared by adding Fe-MOFs metal skeleton material and epoxy resin into cellulose hydrogel and then irradiating with ultraviolet light.

3. The coated slow-release insect-resistant organic fertilizer according to claim 2, characterized in that: The Fe-MOFs metal skeleton material includes one or more of Fe-BDC, Fe-2MI and Fe-BDC / Fe-2MI.

4. The coated slow-release insect-resistant organic fertilizer according to claim 2, characterized in that: The cellulose hydrogel is prepared by firstly introducing sulfhydryl groups into cellulose and then using citric acid as a cross-linking agent.

5. The coated slow-release insect-resistant organic fertilizer according to claim 1, characterized in that: The organic fertilizer granules are obtained by harmlessly treating human and animal feces through an EM composting method, extruding the material through a twin-screw extruder, and granulating the material.

6. A method for preparing a coated slow-release insect-resistant organic fertilizer, characterized in that: The method comprises the following preparation steps: (1) The hydrophobic cellulose and ammonium persulfate are mixed at a mass ratio of 1:1 to 1.5 to obtain a mixture, which is dissolved in deionized water 12 to 13 times the mass of the mixture, and ultrasonically dispersed at 30 to 40 kHz for 30 to 60 minutes at 25° C., butenoic acid, butenol, citric acid and hydrophobic cellulose are added to the mixture at a mass ratio of 0.4 to 0.5:0.5 to 0.6:0.05 to 0.2:1, and reacted at 70 to 80° C. for 2 to 3 hours, and the solid was filtered to obtain a solid, washed with water until neutral, and dried at room temperature for 2 to 3 hours to obtain a cellulose hydrogel; (2) Fe-MOFs metal skeleton material, E-44 epoxy resin and cellulose hydrogel are mixed in a mass ratio of 0.1-0.3:0.5-0.6:1, ultrasonically dispersed at 30-40kHz for 1-2h, heated to 70-80°C, reacted for 2-3h, added with 9-10 times the mass of cellulose hydrogel and 0.5 mol / L acetate buffer solution with a pH of 3.6, stirred at 300-400 r / min for 30-40min, added with 0.05-0.1 times the mass of cellulose hydrogel and water-soluble photoinitiator, ultrasonically dispersed at 40-50kHz for 1-1.5h, and irradiated under ultraviolet light for 30-60min to obtain a coating material; (3) The coating material is placed in an ultrasonic atomizer, and a stable magnetic field with a strength of 0.50 T is applied to assist in spraying the coating material onto the organic fertilizer particles to obtain a coated slow-release insect-resistant organic fertilizer.

7. The method for preparing a coated slow-release insect-resistant organic fertilizer according to claim 6, characterized in that: The preparation method of the hydrophobic cellulose in step (1) is as follows: a. Mix 13.5wt% sodium hydroxide solution and α-cellulose in a mass ratio of 25-30:1, heat to 60°C, stir at 200-300r / min for 4-6h, add ethanol 0.5-0.8 times the mass of the sodium hydroxide solution, filter and take the filter cake, wash the filter cake with water until the pH of the suspension is neutral, place the suspension in a freeze dryer at a temperature of -35°C and a pressure of 25Pa for freeze drying for 20-24h to obtain alkalized cellulose, repeat the above operation until filtration, obtain a new filter cake after filtration, place the new filter cake in a vacuum drying oven at 50-60°C and 50kPa for drying for 7-8h, grind into powder to obtain alkalized cellulose; b. Dry the alkalized cellulose at 100°C for 16 to 30 minutes, mix it with glycidyl methacrylate and dioxane at a molar ratio of 1:5 to 6:5 to 6, heat it to 70 to 80°C, heat it for 6 to 8 hours, then heat it to 120 to 125°C, heat it for 2 to 2.5 hours, wash it with tetrahydrofuran solution for 4 to 5 times, and dry it in a vacuum drying oven at 20 to 30°C and 50 kPa for 10 to 12 hours to obtain modified cellulose; c. Expel the air in the reaction device with nitrogen, mix the modified cellulose and tetrahydrofuran in a mass ratio of 1:3-5, disperse them by ultrasonic at 30-40kHz for 10-15min, introduce hydrogen sulfide gas at a flow rate of 0.5-0.8L / min until the reaction is completed, react at 45-50℃ for 1.8-2d, place in ethanol, wash with ultrasonic at 30-40kHz for 5-6 times, and then place in a vacuum drying oven at 20-30℃, 50kPa for 3-3.5d to obtain hydrophobic cellulose.

8. The method for preparing a coated slow-release insect-resistant organic fertilizer according to claim 6, characterized in that: The preparation method of the water-soluble photoinitiator in step (2) is as follows: 0.6-0.8 g of DBU reagent is added to 10 ml of ether solution containing 1-2 g of ketoprofen, stirred at 200-300 r / min for 60-70 min, filtered to obtain the solid, washed with ether solvent for 3-5 times, and dried under reduced pressure to obtain the solid.

9. The method for preparing a coated slow-release insect-resistant organic fertilizer according to claim 6, characterized in that: The ultraviolet light irradiation condition in step (2) is to use a light intensity of 20 mW / cm 2 Irradiation with 365nm ultraviolet light.

10. The method for preparing a coated slow-release insect-resistant organic fertilizer according to claim 6, characterized in that: The conditions for ultrasonic atomization spraying in step (3) are as follows: a liquid inlet rate of 10 mL / h, an ultrasonic generator frequency of 44 kHz, a power of 2.5 W, and high-purity argon gas as a carrier gas with a flow rate of 3 L / min.