A kind of humic acid liquid fertilizer and its preparation method and application

Abstract

The invention discloses a humic acid liquid fertilizer and a preparation method and application thereof, belonging to the technical field of liquid fertilizers. Organic waste and ferric oxide are ball-milled and mixed, transferred to a muffle furnace, protected by nitrogen and roasted at 280-310 DEG C for 2-2.5 hours, transferred to a reactor and stirred and mixed with 10wt% of hydrogen peroxide aqueous solution and potassium hydroxide powder, extracted for 40-60 minutes under the assistance of ultrasound, filtered to obtain potassium humate extract and filter residue, transferred the potassium humate extract to a stirring kettle, urea, dipotassium hydrogen phosphate, a composite carbon point lubricant and a suspension stabilizer are added to the stirring kettle, and mixed evenly to obtain the humic acid liquid fertilizer; the suspension stabilizer can reduce the generation of flocculation and crystallization in the liquid fertilizer, and the anti-friction lubrication effect of the composite carbon point lubricant helps to reduce the friction between the insoluble solid and the water outlet hole of the drip irrigation equipment, thereby reducing the risk of clogging of the drip irrigation equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid fertilizers, and in particular relates to a humic acid liquid fertilizer and a preparation method and application thereof. Background Art

[0002] Humic acid is an organic substance accumulated from the remains of plants and animals, especially plants, during the decomposition, transformation and geochemical process of microorganisms. The basic structure of its macromolecules includes aromatic rings and alicyclic rings, with functional groups such as carboxyl, hydroxyl and carbonyl attached to the rings. Humic acid can be used as a good soil conditioner, which can promote the ability of crops to absorb water and nutrients, improve the utilization rate of fertilizer nutrients, enhance crop resistance, improve crop quality and improve the physical and chemical properties of soil.

[0003] Humic acid is mainly distributed in soil, water and coal, and its content is higher in low calorific value coal such as peat, lignite and weathered coal. Humic acid obtained from minerals such as peat, lignite and weathered coal by physical and chemical methods is called mineral humic acid. Since mineral sources are non-renewable resources, mineral humic acid is also a non-renewable substance, which does not conform to the concept of green, low-carbon and sustainable development.

[0004] The patent application with publication number CN113277492A discloses a method for preparing potassium humate and biochar from agricultural and forestry wastes, which is helpful for the resource utilization of wastes. The humic acid prepared by conversion is prepared into liquid fertilizer and applied to crops by drip irrigation, which can also save water and fertilizer. However, humic acid liquid fertilizer is generally prone to flocculation and crystallization during storage, and the water outlet holes of drip irrigation equipment are generally small. Long-term low-speed drip irrigation is easy to cause blockage, which limits the application of humic acid liquid fertilizer in drip irrigation fertilization. Summary of the invention

[0005] The purpose of the present invention is to provide a humic acid liquid fertilizer and a preparation method and application thereof, by adding a suspension stabilizer to improve the dispersibility of each component in the humic acid liquid fertilizer, and by adding a composite carbon dot lubricant to reduce the risk of pipe blockage through lubrication.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A humic acid liquid fertilizer has good dispersibility, no aggregates and precipitation are generated after long-term storage, and meets the use requirements of drip irrigation of crops.

[0008] A method for preparing humic acid liquid fertilizer comprises the following steps:

[0009] Step 1: ball-mill the organic waste and ferric oxide, transfer them to a muffle furnace, roast them for 2-2.5 hours under nitrogen protection and at 280-310°C, then transfer them to a reactor and stir and mix them with a 10% by mass aqueous solution of hydrogen peroxide and potassium hydroxide powder, extract them for 40-60 minutes under the assistance of ultrasound at a power of 300-320W, filter them, and obtain potassium humate extract and filter residue.

[0010] Step 2: Transfer the potassium humate extract to a stirring tank, add urea, dipotassium hydrogen phosphate, composite carbon dot lubricant and suspension stabilizer into the stirring tank, mix well, and obtain humic acid liquid fertilizer.

[0011] Furthermore, the usage ratio of organic waste, ferric oxide, aqueous hydrogen peroxide solution and potassium hydroxide powder is 10g:0.05-0.06g:100mL:2.5-2.55g.

[0012] Furthermore, the organic waste is a mixture of dry food waste sludge and straw in a mass ratio of 1:3; the organic matter content of the food waste sludge is ≥50%.

[0013] Furthermore, the dosage ratio of potassium humate extract, urea, dipotassium hydrogen phosphate, composite carbon dot lubricant and suspension stabilizer is 100 mL: 0.4-0.8 g: 0.5-1 g: 0.2-0.4 g: 0.6-0.8 g.

[0014] Further, the suspension stabilizer is prepared by the following steps:

[0015] Step 1: Add tetramethyldivinyldisiloxane, L-cysteine, photocatalyst DMAP, tetrahydrofuran and deionized water into the reactor, stir for 3-5 minutes at 200-300r / min under nitrogen protection, and then heat at a light intensity of 5-6mW / cm 2 The mixture was stirred and reacted for 10-12 minutes under ultraviolet light irradiation with a wavelength of 365 nm to cross-link the thiol group on L-cysteine ​​and a double bond on tetramethyldivinyldisiloxane, and the solvent was removed by rotary evaporation. Unreacted monomers were removed by reduced pressure fractionation to obtain amino acid-modified siloxane.

[0016] Step 2: Add allyl polyoxyethylene ether and deionized water into a reactor and stir to mix, then add thioglycolic acid as a chain transfer agent and ammonium persulfate as an initiator into the reactor at 50-55°C, stir at 200-300r / min for 2-3min, then drop acrylic acid and amino acid modified siloxane into the reactor, and react at 70°C for 2.5-3h by free radical polymerization, adjust the pH value to neutral with sodium hydroxide solution, dialyze the reaction solution with a dialysis bag with a molecular weight cutoff of 1000Da, and freeze-dry the product to obtain a suspension stabilizer.

[0017] Furthermore, the usage ratio of tetramethyldivinyldisiloxane, L-cysteine, photocatalyst DMAP, tetrahydrofuran and deionized water is 1.86 g:1.2 g:0.05-0.06 g:15-20 mL:15-20 mL.

[0018] Furthermore, the usage ratio of allyl polyoxyethylene ether, deionized water, thioglycolic acid, ammonium persulfate, acrylic acid and amino acid-modified siloxane is 100 g: 100-120 mL: 1.2-1.8 g: 1.6-2.4 g: 20-21 g: 30-32 g.

[0019] Furthermore, the composite carbon dot lubricant is prepared by the following steps:

[0020] The filter residue is ground and crushed, vacuum dried, and passed through a 200-mesh sieve to obtain a filter residue powder; the filter residue powder, branched polyethyleneimine with a molecular weight of 500 and anhydrous ethanol are added to a reactor lined with a polytetrafluoroethylene coating, stirred at 300-500 r / min for 5-10 minutes, and then ultrasonically dispersed for 10-15 minutes, and then a hydrochloric acid solution with a mass fraction of 36-38% is added to the reactor and continued to be stirred for 5-10 minutes, and the reaction is kept warm at 180-190° C. for 8-9 hours, cooled naturally, and the reaction solution is filtered through a 0.22 μm microporous filter membrane to remove large particles of solid, and the filtrate is centrifuged at a centrifugal speed of 10000 r / min. The precipitate is collected and freeze-dried, and ground to obtain a composite carbon dot lubricant.

[0021] Furthermore, the usage ratio of the filter residue powder, the branched polyethyleneimine, the anhydrous ethanol and the hydrochloric acid solution is 4-5 g: 1.6-2 g: 80-100 mL: 0.5-0.6 mL.

[0022] Beneficial effects of the present invention:

[0023] The humic acid liquid fertilizer of the present invention uses kitchen waste sludge and straw as raw materials, and makes resource utilization of organic waste, which is green and environmentally friendly. Under the catalysis of ferric oxide and high temperature conditions, the organic waste is catalytically pyrolyzed to prepare potassium humate extract, in which the soluble humic acid content is high, meeting the product requirements of humic acid liquid fertilizer. The humic acid extract is combined with urea and dipotassium hydrogen phosphate to balance the fertilizer effect, which helps to increase the biomass of corn and promote the growth of crops.

[0024] The humic acid liquid fertilizer of the present invention contains a composite carbon point lubricant and a suspension stabilizer. First, amino acid modified siloxane is prepared by the addition reaction between thiol and carbon-carbon double bond, which helps to combine the characteristics of amino acid and organosilicon, and then the suspension stabilizer is prepared by free radical polymerization with propyl polyoxyethylene ether and acrylic acid. The increase of hydrophilic groups can improve its surface activity, help to reduce the surface tension of humic acid liquid fertilizer, improve the dispersibility of each component in humic acid liquid fertilizer, and reduce the generation of flocculation and crystallization in liquid fertilizer. The composite carbon point lubricant prepared by adding branched polyethyleneimine contains a large number of amino groups on the surface, and the suspension stabilizer contains amino acid side chains, which improve the dispersibility of composite carbon point powder through interactions such as hydrogen bonds, and the carbon point has a small diameter and will not block the drip irrigation equipment itself. The anti-friction lubricating effect of the composite carbon point lubricant helps to reduce the friction between the insoluble solid and the water outlet of the drip irrigation equipment, and reduces the risk of clogging the drip irrigation equipment. DETAILED DESCRIPTION

[0025] 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 creative work are within the scope of protection of the present invention.

[0026] Embodiment 1: This embodiment provides a humic acid liquid fertilizer, and its preparation method comprises the following steps:

[0027] S1: Add 18.6 kg tetramethyldivinyldisiloxane, 12 kg L-cysteine, 0.5 kg photocatalyst DMAP, 150 L tetrahydrofuran and 150 L deionized water into the reactor, stir for 3 min under nitrogen protection and 200 r / min, and then heat at a light intensity of 5 mW / cm 2 The mixture was stirred and reacted for 10 minutes under ultraviolet light irradiation with a wavelength of 365 nm to cross-link the thiol group on L-cysteine ​​and a double bond on tetramethyldivinyldisiloxane, and the solvent was removed by rotary evaporation. Unreacted monomers were removed by reduced pressure fractionation to obtain amino acid-modified siloxane.

[0028] S2: Add 20 kg of allyl polyoxyethylene ether and 20 L of deionized water into a reactor and stir to mix. Then, add 0.24 kg of thioglycolic acid and 0.32 kg of ammonium persulfate into the reactor at 50°C, stir at 200 r / min for 2 min, then drop 4 kg of acrylic acid and 6 kg of the amino acid-modified siloxane in step S1 into the reactor, keep the reaction at 70°C for 2.5 h, adjust the pH value to neutral with sodium hydroxide solution, dialyze the reaction solution with a dialysis bag with a molecular weight cutoff of 1000 Da, and freeze-dry the product to obtain a suspension stabilizer.

[0029] S3: 100 kg of organic waste and 0.5 kg of ferric oxide were ball-milled and mixed, transferred to a muffle furnace, and calcined at 280 ° C for 2 h under nitrogen protection. Then, they were transferred to a reactor and stirred with 1000 L of 10% hydrogen peroxide aqueous solution and 25 kg of potassium hydroxide powder. The mixture was extracted for 40 min under ultrasonic assistance at a power of 300 W, and filtered to obtain potassium humate extract and filter residue.

[0030] Among them, organic waste is a mixture of dry food waste sludge and straw in a mass ratio of 1:3; the organic matter content of the food waste sludge is ≥50%.

[0031] S4: Grind and crush the filter residue in step S3, vacuum dry it, and pass it through a 200-mesh sieve to obtain a filter residue powder; add 40 kg of the filter residue powder, 16 kg of branched polyethyleneimine with a molecular weight of 500, and 800 L of anhydrous ethanol into a reactor lined with a polytetrafluoroethylene coating, stir at 300 r / min for 5 min, and then ultrasonically disperse for 10 min, then add 5 L of a 36% hydrochloric acid solution to the reactor and continue stirring for 5 min, keep the reaction at 180°C for 8 h, cool it naturally, filter the reaction solution through a 0.22 μm microporous filter membrane to remove large particles of solid, centrifuge the filtrate at a centrifugal speed of 10,000 r / min, collect the precipitate, freeze-dry it, and grind it to obtain a composite carbon dot lubricant.

[0032] S5: 100L of the potassium humate extract in step S3 is transferred to a stirring tank, 0.4kg of urea, 0.5kg of dipotassium hydrogen phosphate, 0.2kg of the composite carbon dot lubricant in step S4 and 0.6kg of the suspension stabilizer in step S2 are added to the stirring tank, and after mixing evenly, humic acid liquid fertilizer is obtained.

[0033] Embodiment 2: This embodiment provides a humic acid liquid fertilizer, and its preparation method comprises the following steps:

[0034] S1: Add 18.6 kg tetramethyldivinyldisiloxane, 12 kg L-cysteine, 0.55 kg photocatalyst DMAP, 180 L tetrahydrofuran and 180 L deionized water into the reactor, stir for 4 min under nitrogen protection and 250 r / min, and then heat at a light intensity of 5.5 mW / cm 2 The mixture was stirred and reacted for 11 minutes under ultraviolet light irradiation with a wavelength of 365 nm to cross-link the thiol group on L-cysteine ​​and a double bond on tetramethyldivinyldisiloxane. The solvent was removed by rotary evaporation and unreacted monomers were removed by reduced pressure fractionation to obtain amino acid-modified siloxane.

[0035] S2: Add 20 kg of allyl polyoxyethylene ether and 22 L of deionized water into a reactor and stir to mix. Then, add 0.30 kg of thioglycolic acid and 0.40 kg of ammonium persulfate into the reactor at 52 ° C., stir at 250 r / min for 2.5 min, then add 4.1 kg of acrylic acid and 6.2 kg of the amino acid-modified siloxane in step S1 dropwise into the reactor, keep the reaction at 70 ° C for 2.8 h, adjust the pH value to neutral with sodium hydroxide solution, dialyze the reaction solution with a dialysis bag with a molecular weight cutoff of 1000 Da, and freeze-dry the product to obtain a suspension stabilizer.

[0036] S3: 100 kg of organic waste and 0.55 kg of ferric oxide were ball-milled and mixed, transferred to a muffle furnace, and calcined at 295 ° C for 2.2 h under nitrogen protection. Then, they were transferred to a reactor and stirred with 1000 L of 10% hydrogen peroxide aqueous solution and 25.2 kg of potassium hydroxide powder. The mixture was extracted for 50 min under ultrasonic assistance at a power of 310 W, and filtered to obtain potassium humate extract and filter residue.

[0037] Among them, organic waste is a mixture of dry food waste sludge and straw in a mass ratio of 1:3; the organic matter content of the food waste sludge is ≥50%.

[0038] S4: Grind and crush the filter residue in step S3, vacuum dry it, and pass it through a 200-mesh sieve to obtain a filter residue powder; add 45 kg of the filter residue powder, 18 kg of branched polyethyleneimine with a molecular weight of 500, and 900 L of anhydrous ethanol into a reactor lined with a polytetrafluoroethylene coating, stir at 400 r / min for 8 min, and then ultrasonically disperse for 12 min, then add 5.5 L of a 37% hydrochloric acid solution to the reactor and continue stirring for 8 min, keep the reaction at 185°C for 8.5 h, cool it naturally, filter the reaction solution through a 0.22 μm microporous filter membrane to remove large particles of solid, centrifuge the filtrate at a centrifugal speed of 10,000 r / min, collect the precipitate, freeze-dry it, and grind it to obtain a composite carbon dot lubricant.

[0039] S5: 100L of the potassium humate extract in step S3 is transferred to a stirring tank, and 0.6kg of urea, 0.8kg of dipotassium hydrogen phosphate, 0.3kg of the composite carbon dot lubricant in step S4 and 0.7kg of the suspension stabilizer in step S2 are added to the stirring tank, and mixed evenly to obtain humic acid liquid fertilizer.

[0040] Embodiment 3: This embodiment provides a humic acid liquid fertilizer, and its preparation method comprises the following steps:

[0041] S1: Add 18.6 kg tetramethyldivinyldisiloxane, 12 kg L-cysteine, 0.6 kg photocatalyst DMAP, 200 L tetrahydrofuran and 200 L deionized water into the reactor, stir for 5 min at 300 r / min under nitrogen protection, and then heat at 6 mW / cm 2 The mixture was stirred and reacted for 12 minutes under ultraviolet light irradiation with a wavelength of 365 nm to cross-link the thiol group on L-cysteine ​​and a double bond on tetramethyldivinyldisiloxane, and the solvent was removed by rotary evaporation. Unreacted monomers were removed by reduced pressure fractionation to obtain amino acid-modified siloxane.

[0042] S2: Add 20 kg of allyl polyoxyethylene ether and 24 L of deionized water into a reactor and stir to mix. Then, add 0.36 kg of thioglycolic acid and 0.48 kg of ammonium persulfate into the reactor at 55°C, stir at 300 r / min for 3 min, then drop 4.2 kg of acrylic acid and 6.4 kg of the amino acid-modified siloxane in step S1 into the reactor, keep the reaction at 70°C for 3 h, adjust the pH value to neutral with sodium hydroxide solution, dialyze the reaction solution with a dialysis bag with a molecular weight cutoff of 1000 Da, and freeze-dry the product to obtain a suspension stabilizer.

[0043] S3: 100 kg of organic waste and 0.6 kg of ferric oxide were ball-milled and mixed, transferred to a muffle furnace, and calcined at 310 ° C for 2.5 h under nitrogen protection. Then, they were transferred to a reactor and stirred with 1000 L of 10% hydrogen peroxide aqueous solution and 25.5 kg of potassium hydroxide powder. The mixture was extracted for 60 min under ultrasonic assistance at a power of 320 W, and filtered to obtain potassium humate extract and filter residue.

[0044] Among them, organic waste is a mixture of dry food waste sludge and straw in a mass ratio of 1:3; the organic matter content of the food waste sludge is ≥50%.

[0045] S4: Grind and crush the filter residue in step S3, vacuum dry it, and pass it through a 200-mesh sieve to obtain a filter residue powder; add 50 kg of the filter residue powder, 20 kg of branched polyethyleneimine with a molecular weight of 500, and 1000 L of anhydrous ethanol into a reactor lined with a polytetrafluoroethylene coating, stir at 500 r / min for 10 min, and then ultrasonically disperse for 15 min, then add 6 L of a 38% hydrochloric acid solution to the reactor and continue stirring for 10 min, keep the reaction at 190° C. for 9 h, cool it naturally, filter the reaction solution through a 0.22 μm microporous filter membrane to remove large particles of solid, centrifuge the filtrate at a centrifugal speed of 10,000 r / min, collect the precipitate, freeze-dry it, and grind it to obtain a composite carbon dot lubricant.

[0046] S5: 100L of the potassium humate extract in step S3 is transferred to a stirring tank, and 0.8kg of urea, 1kg of dipotassium hydrogen phosphate, 0.4kg of the composite carbon dot lubricant in step S4 and 0.8kg of the suspension stabilizer in step S2 are added to the stirring tank, and mixed evenly to obtain humic acid liquid fertilizer.

[0047] According to the industry standard NY 1106-2010 "Water-soluble fertilizer containing humic acid", the soluble humic acid content in the humic acid liquid fertilizer in the embodiment is all greater than 40g / L, which meets the technical indicator of humic acid content ≥30g / L in the liquid product of water-soluble fertilizer containing humic acid.

[0048] Comparative Example 1: Based on Example 3, branched polyethyleneimine is not added in step S4 to prepare carbon dot powder, and the composite carbon dot lubricant in step S5 is replaced. The remaining steps remain unchanged to prepare humic acid liquid fertilizer.

[0049] Comparative Example 2: Based on Example 3, the composite carbon dot lubricant is not added in step S5, and the other steps remain unchanged to prepare humic acid liquid fertilizer.

[0050] Comparative Example 3: Based on Example 3, the amino acid-modified siloxane is not added in step S2 to prepare the suspension agent, the suspension stabilizer in step S5 is replaced, and the other steps remain unchanged to prepare humic acid liquid fertilizer.

[0051] Comparative Example 4: Based on Example 3, a commercially available suspending agent was used to replace the suspension stabilizer in step S5, and the other steps remained unchanged to prepare a humic acid liquid fertilizer.

[0052] Comparative Example 5: Based on Example 3, no suspension stabilizer is added in step S5, and the other steps remain unchanged to prepare humic acid liquid fertilizer.

[0053] In the embodiments and comparative examples, branched polyethyleneimine with a molecular weight of 500 was purchased from Hubei Yamade Biotechnology Co., Ltd., with an active ingredient content of 99%; the commercially available suspending agent was purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd., model K-288; the straw used was corn straw, and the food waste sludge was provided by the Hefei Feifan Food Waste Treatment Plant.

[0054] The physical and chemical properties of food waste biogas residue are shown in Table 1:

[0055] Table 1 Physical and chemical properties of food waste biogas residue

[0056]

[0057] Performance tests were conducted on Examples 1 to 3 and Comparative Examples 1 to 5. Different humic acid liquid fertilizers were filled into transparent glass bottles and stored for 60 days under the same conditions to obtain different samples, and the state of the liquid in the bottles was observed; the suspension rates of different humic acid liquid fertilizer samples were tested with reference to GB14825-2006; and different samples were filtered using a glass sand core crucible (filter plate pore size of 4-7 μm) with an international standard of P7 with reference to NY / T 1973-2010, and the filtered solid content of different samples was calculated (filtered solid content = filtered solid mass / humic acid liquid fertilizer sample mass × 100%). The stability test results of the humic acid liquid fertilizer are shown in Table 2:

[0058] Table 2 Stability test results of humic acid liquid fertilizer

[0059]

[0060] It can be seen from Table 1 that the humic acid liquid fertilizers in Examples 1 to 3 have no aggregates and precipitation after being stored for 60 days, and their suspension rate is relatively high, indicating that the dispersion degree of each component in the humic acid liquid fertilizer is high, and the filtered solid content is less than 1%.

[0061] The suspension rates of the samples in Comparative Examples 3-4 are lower than those in the examples, and the filtered solid content is increased, indicating that the suspension stabilizer added to the samples in the surface examples has a good dispersing effect on the humic acid liquid fertilizer, and can reduce the generation of flocculation and crystallization in the liquid fertilizer. Comparative Examples 1 and 2 show that the composite carbon dot lubricant prepared by adding branched polyethyleneimine can reduce the filtered solid content, and the suspension rate of the sample in Comparative Example 1 is lower than that of the example, because the composite carbon dot lubricant contains a large number of amino groups on the surface, and the suspension stabilizer contains amino acid side chains, which improve the dispersibility of the composite carbon dot powder through interactions such as hydrogen bonds, thereby improving the suspension rate of the sample, and the composite carbon dot lubricant has an anti-friction lubricating effect, which can increase the proportion of insoluble solids passing through the sieve plate and reduce the risk of clogging of the drip irrigation equipment.

[0062] The humic acid liquid fertilizer in Example 3 was used as an example to test the fertilizer efficiency: a root box with an open top and a length, width and height of 40 cm × 7 cm × 35 cm was selected, and the test soil (taken from Changfeng County, Hefei City) was removed of impurities and dried before being loaded into the root box, with a soil loading of 10.9 kg / box.

[0063] Corn seeds (Zhengdan 958) were sown in the center of the root box after germination for 3 days, with a sowing depth of 5 cm and a sowing amount of 2 seeds. The seedlings were thinned to 1 seed after 10 days of emergence. The average soil temperature during the cultivation period was 26.3°C. Drip irrigation equipment was used to drip irrigate the soil surface of the root box. One group was drip irrigated with humic acid liquid fertilizer in Example 3, and the other group was drip irrigated with clean water as a blank control. Drip irrigation was performed every 3 days to keep the soil moisture content at about 60%. During the experiment, the day and night temperature was 28 / 21°C, the day and night light time was 16 / 8h, and the light intensity was 300μmol / (m 2 ·s), air humidity 70%, each group was repeated 5 times, and the average value was taken.

[0064] 50 days after sowing, corn was cut at the soil level. The aboveground part was divided into two parts: stalks and leaves. The aboveground part and the root system were rinsed with distilled water, and the water was absorbed. Then, the aboveground part and the root system were sterilized at 105°C for 30 minutes, and dried at 65°C to constant weight. The biomass of each organ was measured. The effect of applying humic acid liquid fertilizer on the biomass of each organ of corn is shown in Table 3:

[0065] Table 3 Effects of applying humic acid liquid fertilizer on the biomass of various organs of corn

[0066]

[0067] It can be seen from Table 3 that the humic acid liquid fertilizer in drip irrigation Example 3 significantly increases the biomass of corn compared to the blank control, which helps to promote the growth of crops.

[0068] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing humic acid liquid fertilizer, characterized in that: The steps include: Step 1: ball-milling the organic waste and ferric oxide, transferring them to a muffle furnace, calcining them at 280-310°C for 2-2.5h under nitrogen protection, transferring them to a reactor, stirring and mixing them with a 10wt% aqueous hydrogen peroxide solution and potassium hydroxide powder, leaching them for 40-60min under the assistance of ultrasound at a power of 300-320W, filtering them, and obtaining a potassium humate extract and a filter residue; Step 2: Transfer the potassium humate extract to a stirring kettle, add urea, dipotassium hydrogen phosphate, a composite carbon dot lubricant and a suspension stabilizer to the stirring kettle, mix evenly, and obtain a humic acid liquid fertilizer; the amount ratio of the potassium humate extract, urea, dipotassium hydrogen phosphate, the composite carbon dot lubricant and the suspension stabilizer is 100mL: 0.4-0.8g: 0.5-1g: 0.2-0.4g: 0.6-0.8g; The composite carbon dot lubricant is prepared by the following steps: The filter residue is ground and crushed, vacuum dried, and passed through a 200-mesh sieve to obtain a filter residue powder; the filter residue powder, branched polyethyleneimine with a molecular weight of 500, and anhydrous ethanol are added to a reactor lined with a polytetrafluoroethylene coating, stirred at 300-500 r / min for 5-10 min, and then ultrasonically dispersed for 10-15 min, and then a hydrochloric acid solution with a mass fraction of 36-38% is added to the reactor and continued to be stirred for 5-10 min, and the reaction is kept at 180-190° C. for 8-9 h, cooled naturally, and the reaction solution is filtered through a 0.22 μm microporous filter membrane to remove large particles of solid, and the filtrate is centrifuged at a centrifugal speed of 10000 r / min, and the precipitate is collected and freeze-dried, and ground to obtain a composite carbon dot lubricant; The suspension stabilizer is prepared by the following steps: Tetramethyldivinyldisiloxane, L-cysteine, photocatalyst DMAP, tetrahydrofuran and deionized water were added to the reactor, stirred for 3-5 min at 200-300 r / min under nitrogen protection, and then heated at a light intensity of 5-6 mW / cm 2 and reacting under ultraviolet light with a wavelength of 365 nm for 10-12 minutes with stirring to crosslink the thiol group on L-cysteine ​​and a double bond on tetramethyldivinyldisiloxane, removing the solvent by rotary evaporation, and removing unreacted monomers by reduced pressure fractionation to obtain amino acid-modified siloxane; Add allyl polyoxyethylene ether and deionized water into a reaction kettle and stir to mix, add thioglycolic acid and ammonium persulfate at 50-55°C, stir at 200-300r / min for 2-3min, then drop acrylic acid and amino acid modified siloxane, keep warm at 70°C for reaction for 2.5-3h, adjust the pH value to neutral with sodium hydroxide solution, dialyze with a dialysis bag with a molecular weight cutoff of 1000Da, and freeze-dry to obtain a suspension stabilizer.

2. The method for preparing a humic acid liquid fertilizer according to claim 1, characterized in that: The usage ratio of the allyl polyoxyethylene ether, deionized water, thioglycolic acid, ammonium persulfate, acrylic acid and amino acid-modified siloxane is 100g: 100-120mL: 1.2-1.8g: 1.6-2.4g: 20-21g: 30-32g.

3. The method for preparing a humic acid liquid fertilizer according to claim 1, characterized in that: The usage ratio of the organic waste, ferric oxide, aqueous hydrogen peroxide solution and potassium hydroxide powder is 10g: 0.05-0.06g: 100mL: 2.5-2.55g.

4. The method for preparing a humic acid liquid fertilizer according to claim 1, characterized in that: The organic waste is formed by mixing dry food waste sludge and straw in a mass ratio of 1:3; the organic matter content of the food waste sludge is ≥50%.

5. The method for preparing a humic acid liquid fertilizer according to claim 1, characterized in that: The dosage ratio of tetramethyldivinyldisiloxane, L-cysteine, photocatalyst DMAP, tetrahydrofuran and deionized water is 1.86g:1.2g:0.05-0.06g:15-20mL:15-20mL.

6. The method for preparing a humic acid liquid fertilizer according to claim 1, characterized in that: The usage ratio of the filter residue powder, branched polyethyleneimine, anhydrous ethanol and hydrochloric acid solution is 4-5g:1.6-2g:80-100mL:0.5-0.6mL.

7. A humic acid liquid fertilizer, characterized in that: The humic acid liquid fertilizer is prepared by the preparation method of any one of claims 1 to 6.

8. Use of the humic acid liquid fertilizer according to claim 7 in drip irrigation of crops.

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