Humic acid organic water-soluble fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of fertilizer manufacturing, and discloses a humic acid organic water-soluble fertilizer and a preparation method thereof. The humic acid organic water-soluble fertilizer is specifically prepared from the following raw materials in parts by weight: 45 to 55 parts of citric acid functionalized humic acid component loaded with potassium element, 30 to 50 parts of urea, 10 to 30 parts of potassium sulfate, 20 to 40 parts of monoammonium phosphate, 15 to 20 parts of plant ash, 3 to 10 parts of calcium nitrate, 5 to 10 parts of trace element and 0.1 to 3 parts of compound additive, wherein the potassium element loaded citric acid functionalized humic acid component is prepared by loading potassium ions on citric acid functional groups grafted on the surface of humic acid. When the humic acid organic water-soluble fertilizer product researched and developed by the invention is used, the loss of nutrient elements is less, the utilization rate is high, and the humic acid organic water-soluble fertilizer product has a remarkable promoting effect on the growth of crops.

Description

Technical Field

[0001] This invention relates to the field of fertilizer manufacturing technology, specifically to a humic acid organic water-soluble fertilizer and its preparation method. Background Technology

[0002] Research has found that some nutrients in fertilizers are prone to chemical reactions with soil components and become ineffective. An effective way to solve this problem is to add chelating agents to fertilizers, so that nutrient ions and chelating agents can form stable chelates, thereby reducing nutrient loss and improving fertilizer utilization.

[0003] Humic acid is a polymer composed of benzene rings, fused rings, and heterocycles (such as pyridine, pyrrole, furan, etc.) linked by bridging bonds (such as -O-, -CH2-, -S-, etc.). Its molecules contain a variety of oxygen-containing functional groups, such as carboxyl groups (-COOH), phenolic hydroxyl groups (-OH), alcoholic hydroxyl groups, carbonyl groups (C=O), methoxy groups (-OCH3), etc., which makes humic acid usable as a chelating agent in fertilizers.

[0004] Compared to the traditional chelating agent ethylenediaminetetraacetic acid (EDTA), natural humic acid chelating agents have advantages such as low cost, wide availability, and comprehensive nutritional content. However, the molecular structure of humic acid is relatively complex, and steric hindrance prevents some oxygen-containing groups from effectively exerting their chelating effect, thus limiting the chelating capacity of humic acid. Studies have found that grafting modification of humic acid to increase its oxygen-containing functional group content can effectively improve its chelating performance.

[0005] In addition, small-molecule citric acid can also be used as a chelating agent in fertilizers. It has good chelating ability, but it is easy to decompose. Although it is beneficial for plant absorption, it has poor stability and may cause nutrients to be released rapidly in the soil, making it difficult to nourish crops for a long time. Summary of the Invention

[0006] This invention develops a humic acid organic water-soluble fertilizer that can effectively improve the utilization rate of nutrient elements. It can provide crops with more comprehensive nutrients and significantly promote crop growth.

[0007] A humic acid organic water-soluble fertilizer comprises the following raw materials in parts by weight: 45-55 parts of potassium-loaded citric acid-functionalized humic acid components; 30-50 parts urea; 10-30 parts potassium sulfate; 20-40 parts monoammonium phosphate; 15-20 parts wood ash; 3-10 parts calcium nitrate; 5-10 parts trace elements; 0.1-3 parts of compound additives; Among them, the potassium-loaded citric acid functionalized humic acid component is prepared by loading potassium ions onto the surface of humic acid with citric acid functional groups.

[0008] Preferably, the method for preparing the potassium-loaded citric acid-functionalized humic acid component is as follows: Based on the nucleophilic substitution reaction mechanism, alkenylated citrate was prepared from citrate and alkenylated haloalkanes. Using organic peroxy acid as an oxidant, the alkenyl functional groups of alkenyl citrate are epoxidized to obtain epoxidized citrate. Based on the ring-opening reaction mechanism of epoxy, epoxidized citrate is grafted onto a humic acid matrix rich in carboxyl and phenolic hydroxyl functional groups to obtain citrate-esterified humic acid. Based on the saponification reaction mechanism, a potassium-loaded citric acid functionalized humic acid component was prepared using citric acid esterified humic acid and potassium hydroxide as raw materials.

[0009] Preferably, the citrate is tributyl citrate or triethyl citrate.

[0010] Preferably, the alkenylated haloalkane is one of 6-chloro-1-hexene, 6-bromo-1-hexene, 5-chloro-1-pentene, and 8-bromo-1-octene.

[0011] Preferably, the organic peroxyacid is one of peracetic acid, peroxybenzoic acid, and m-chloroperoxybenzoic acid.

[0012] Preferably, the amount of citrate in the potassium-loaded citric acid functionalized humic acid component is 3-15 wt% of the amount of humic acid.

[0013] Preferably, the trace element is one or a combination of more than one of zinc sulfate, copper sulfate, borax, and ammonium molybdate.

[0014] Preferably, the composite additive includes a dispersant and a wetting agent.

[0015] Preferably, the dispersant is sodium methylene bisnaphthalene sulfonate or sodium lignin sulfonate; Preferably, the wetting agent is sodium dodecylbenzenesulfonate or sodium dodecyl sulfate. Beneficial effects

[0016] This invention utilizes chemical grafting to graft small-molecule citric acid onto a humic acid matrix, resulting in citric acid-functionalized humic acid with excellent chelating ability and good stability. The technical method is as follows: Using citrate ester as raw material, and utilizing compounds containing both alkenyl and halogen functional groups, alkenyl functional groups are grafted onto citrate ester based on the nucleophilic substitution reaction mechanism. The alkenyl functional groups are then subjected to epoxidation treatment. Based on the epoxide ring-opening reaction mechanism, citric acid is grafted onto a humic acid matrix rich in carboxyl and phenolic hydroxyl functional groups. Citric acid is used to functionalize humic acid to load potassium ions. Finally, humic acid organic water-soluble fertilizer is produced by mixing it with other nutrients and additives. The experimental results show that the humic acid organic water-soluble fertilizer prepared by this invention has a significant promoting effect on the growth of Chinese cabbage. Detailed Implementation

[0017] This invention utilizes citric acid to graft and modify humic acid to prepare a new citric acid-functionalized humic acid. It not only retains the unique chemical composition and structure of humic acid, which plays a key role in improving soil physicochemical properties and promoting crop growth, but also improves the chelating ability of humic acid by grafting citric acid, and at the same time improves the technical defects of small molecule citric acid, which is easy to decompose and unstable. Example 1:

[0018] The preparation process for monoepoxy citrate monomers is as follows: Step 1: Utilizing the nucleophilic substitution reaction mechanism, a nucleophilic substitution reaction occurs between the hydroxyl functional group of tributyl citrate and the chlorine functional group of 6-chloro-1-hexene to generate a monoalkenyl citrate monomer. Step 2: Using organic peroxy acid as an oxidant, an epoxidation reaction is carried out through the alkenyl functional group of the monoalkenyl citrate monomer to generate a monoepoxy citrate monomer, the chemical structural formula of which is: ; Among them, the organic peroxy acid is selected from peracetic acid, peroxybenzoic acid, and m-chloroperoxybenzoic acid; in this experimental example, m-chloroperoxybenzoic acid is preferred. The specific experimental steps for preparing monoepoxy citrate monomers are as follows: 3.6 g of tributyl citrate and 40 mL of acetone were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 1.3 mL of 6-chloro-1-hexene and 0.5 mL of triethylamine catalyst were added dropwise to the three-necked flask. The mixture was heated to 60 °C and refluxed with stirring for 4 h. After cooling to room temperature, the solvent was removed by rotary evaporation. The mixture was washed repeatedly with ethanol and dried under vacuum to obtain the monoalkenyl citrate monomer. 2.1 g of monoalkenyl citrate monomer and 30 mL of chloroform were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 30 mL of chloroform solution containing 4.5 g of m-chloroperoxybenzoic acid was added dropwise to the three-necked flask. The mixture was heated to 50 °C and stirred for 20 h. After cooling to room temperature, the mixture was washed successively with saturated sodium bicarbonate aqueous solution and deionized water. The aqueous layer was separated and dried with anhydrous magnesium sulfate. The solvent was removed by rotary evaporation and the mixture was dried under vacuum to obtain the monoepoxy citrate monomer. The 1H NMR spectrum of the monoepoxy citrate monomer is characterized as follows: 1 H NMR (CDCl3, 400MHz) δ: 0.85-0.89(t, 6H), 0.91-0.95(t, 3H), 1.27-1.67(m, 18H), 2.98(s, 4H), 3.42-3.43 (d, 2H), 3.56-3.59 (t, 2H), 3.67-3.73 (m, 1H), 4.08-4.11 (t, 4H), 4.15-4.19 (t, 2H). Example 2:

[0019] Preparation of citric acid hydrate humic acid HA-Ⅰ: 1 part by weight of monoepoxy citrate monomer is used to modify 10 parts by weight of humic acid. The monoepoxy citrate monomer undergoes an epoxy ring-opening reaction with the epoxy functional group and the hydroxyl or carboxyl functional group contained in the humic acid to obtain citric acid hydrate humic acid HA-Ⅰ. The specific experimental steps for preparing citric acid esterified humic acid HA-Ⅰ are as follows: 10g of humic acid (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number H108498) and 100mL of acetone were added to a three-necked flask, heated to 40℃ and stirred until completely dissolved. Then, 1.0g of monoepoxy citrate monomer and 0.4g of triphenylphosphine catalyst were added to the three-necked flask in sequence, heated to 60℃ and stirred for 10h. The solvent was removed by rotary evaporation, and the mixture was washed with cyclohexane to obtain citric acid esterified humic acid HA-Ⅰ. Example 3:

[0020] The citrate esterified humic acid HA-II was prepared, and its only difference from the citrate esterified humic acid HA-I was that 0.3g of monoepoxy citrate monomer was used instead of 1.0g of monoepoxy citrate monomer. Example 4:

[0021] The citrate esterified humic acid HA-Ⅲ was prepared, and its only difference from the citrate esterified humic acid HA-Ⅰ was that 1.5 g of monoepoxy citrate monomer was used instead of 1.0 g of monoepoxy citrate monomer. Example 5:

[0022] Preparation of potassium-loaded citric acid functionalized humic acid I: Based on the saponification reaction mechanism, in the presence of potassium hydroxide, the ester functional group in citric acid esterified humic acid HA-I undergoes a hydrolysis reaction to generate potassium-loaded citric acid functionalized humic acid I. The specific experimental steps for preparing potassium-loaded citric acid functionalized humic acid I are as follows: 5g of citric acid esterified humic acid HA-I, 7.5g of sodium hydroxide, and 100mL of deionized water are added to a three-necked flask and stirred at room temperature until completely dissolved. Then, the temperature is raised to 80℃ and stirred for 12h. After cooling to room temperature, the mixture is filtered and dried under vacuum to obtain potassium-loaded citric acid functionalized humic acid I. Example 6:

[0023] Potassium-loaded citric acid functionalized humic acid II was prepared. The only difference between it and potassium-loaded citric acid functionalized humic acid I is that citric acid esterified humic acid HA-II is used instead of citric acid esterified humic acid HA-I. Example 7:

[0024] Potassium-loaded citric acid functionalized humic acid III was prepared, and its only difference from potassium-loaded citric acid functionalized humic acid I was that citric acid esterified humic acid HA-III was used instead of citric acid esterified humic acid HA-I. Example 8:

[0025] A humic acid organic water-soluble fertilizer comprises the following raw materials in parts by weight: 50 parts of potassium-loaded citric acid-functionalized humic acid; 40 parts urea; 20 parts potassium sulfate; 30 parts monoammonium phosphate; 18 parts wood ash; 5 parts calcium nitrate; 2 parts zinc sulfate; 3 parts copper sulfate; 2 parts borax; 1 part ammonium molybdate; 0.5 parts sodium lignosulfonate dispersant; 0.5 parts sodium dodecylbenzenesulfonate wetting agent; Among them, potassium-loaded citric acid functionalized humic acid is one of potassium-loaded citric acid functionalized humic acid I, potassium-loaded citric acid functionalized humic acid II, and potassium-loaded citric acid functionalized humic acid II. Example 9:

[0026] A method for preparing a humic acid organic water-soluble fertilizer includes the following steps: Step 1: According to the formula of humic acid organic water-soluble fertilizer, add each raw material into a pulverizer for pulverization and mixing to prepare fertilizer powder with an average particle size of 200 mesh. Step 2: Add fertilizer powder into a disc granulator. The fertilizer powder tumbles and agglomerates under the rotation of the disc, gradually forming granules. Set the disc speed to 25 r / min to prepare fertilizer granules with an average particle size of 2 mm. Step 3: Sieve the fertilizer granules to remove the fertilizer powder mixed in, and dry them at 60℃ for 5 hours to obtain humic acid organic water-soluble fertilizer. When the potassium-loaded citric acid-functionalized humic acid is potassium-loaded citric acid-functionalized humic acid I, the resulting fertilizer product is denoted as humic acid organic water-soluble fertilizer I. When the potassium-loaded citric acid-functionalized humic acid is potassium-loaded citric acid-functionalized humic acid II, the resulting fertilizer product is denoted as humic acid organic water-soluble fertilizer II. When the potassium-loaded citric acid-functionalized humic acid is potassium-loaded citric acid-functionalized humic acid III, the resulting fertilizer product is denoted as humic acid organic water-soluble fertilizer III. Performance testing:

[0027] I. Elemental Analysis: (1) Analysis of C, H and N elements: The humic acid organic water-soluble fertilizer was dried in an oven at 100℃ for 2h and tested using a Vario ELIII CHN type elemental analyzer. The test conditions were set as follows: high purity oxygen 0.2MPa, oxygen 0.12MPa, and oven temperature 1150℃. The contents of C, H and N elements were calculated. (2) P element analysis: Phosphorus in fertilizers usually exists in the form of phosphorus pentoxide (P2O5). The content of P2O5 was determined according to GB / T 8573-2017 "Determination of available phosphorus content in compound fertilizers". (3) K element analysis: Potassium in fertilizers usually exists in the form of potassium oxide (K2O). The K2O content is determined according to the NY / T 2540-2014 standard "Determination of potassium content in fertilizers". II. Fertilizer Efficacy Test: The crop effect of humic acid organic water-soluble fertilizer was characterized through a pot experiment on Chinese cabbage. The specific experimental methods are as follows: All pots used in the experiment had a bottom diameter of 18cm, a top diameter of 22cm, and a height of 15cm. Each pot contained 2kg of soil and 2g of humic acid organic water-soluble fertilizer. The soil was air-dried and passed through a 2mm sieve. The soil and fertilizer samples were mixed evenly, placed in the pots, and then the seeds were sown evenly. A layer of soil was then sprinkled on top, just enough to cover the seeds. 20 cabbage seeds were sown in each pot and placed in the same outdoor environment for growth. After the seedlings had grown out, 3 seedlings were left in each pot. The fertilizer sample was dissolved in water to prepare a 5g / L fertilizer solution, which was sprayed on each pot with 100mL of fertilizer solution. After that, the pots were watered regularly and in measured quantities every other day, and the locations were randomly changed. Samples were taken after 40 days. The roots of the cabbage seedlings were cleaned and dried before the relevant growth indicators of the plants were measured. The experimental results are shown in Table 1-2 below.

[0028] Table 1. Elemental analysis results of humic acid organic water-soluble fertilizer Product Type C(wt,%) H(wt,%) N(wt,%) <![CDATA[P2O5(wt,%)]]> <![CDATA[K2O(wt,%)]]> Humic acid organic water-soluble fertilizer I 40.34 3.55 12.14 8.25 11.41 Humic Acid Organic Water-Soluble Fertilizer II 39.85 3.76 12.53 8.42 11.29 Humic acid organic water-soluble fertilizer III 41.72 3.71 11.89 8.29 11.25 Table 2. Fertilizer Efficiency Test Results of Humic Acid Organic Water-Soluble Fertilizer Product Type Maximum leaf length (cm) Maximum leaf width (cm) Plant height (cm) Humic acid organic water-soluble fertilizer I 18.0 15.3 27.1 Humic Acid Organic Water-Soluble Fertilizer II 17.2 14.5 26.8 Humic acid organic water-soluble fertilizer III 18.8 15.6 27.3 Blank test (no fertilizer applied) 10.6 7.9 18.5 Based on a comprehensive analysis of the above experimental results, the following conclusions can be drawn: The humic acid organic water-soluble fertilizer prepared by the present invention using potassium-loaded citric acid functionalized humic acid has a significant promoting effect on the growth of Chinese cabbage.

Claims

1. A humic acid organic water-soluble fertilizer, characterized in that, Including the following parts by weight of raw materials: 45-55 parts of potassium-loaded citric acid-functionalized humic acid components; 30-50 parts urea; 10-30 parts potassium sulfate; 20-40 parts monoammonium phosphate; 15-20 parts wood ash; 3-10 parts calcium nitrate; 5-10 parts trace elements; 0.1-3 parts of compound additives; Among them, the potassium-loaded citric acid functionalized humic acid component is prepared by loading potassium ions onto the surface of humic acid with citric acid functional groups.

2. The humic acid organic water-soluble fertilizer according to claim 1, characterized in that, The method for preparing the potassium-loaded citric acid-functionalized humic acid component is as follows: Based on the nucleophilic substitution reaction mechanism, alkenylated citrate was prepared from citrate and alkenylated haloalkanes. Using organic peroxy acid as an oxidant, the alkenyl functional groups of alkenyl citrate are epoxidized to obtain epoxidized citrate. Based on the ring-opening reaction mechanism of epoxy, epoxidized citrate is grafted onto a humic acid matrix rich in carboxyl and phenolic hydroxyl functional groups to obtain citrate-esterified humic acid. Based on the saponification reaction mechanism, a potassium-loaded citric acid functionalized humic acid component was prepared using citric acid esterified humic acid and potassium hydroxide as raw materials.

3. The humic acid organic water-soluble fertilizer according to claim 2, characterized in that, The citrate ester is tributyl citrate or triethyl citrate.

4. The humic acid organic water-soluble fertilizer according to claim 2, characterized in that, The alkenylated haloalkane is one of 6-chloro-1-hexene, 6-bromo-1-hexene, 5-chloro-1-pentene, and 8-bromo-1-octene.

5. The humic acid organic water-soluble fertilizer according to claim 2, characterized in that, The organic peroxyacid is one of peracetic acid, peroxybenzoic acid, and m-chloroperoxybenzoic acid.

6. The humic acid organic water-soluble fertilizer according to claim 2, characterized in that, The amount of citrate in the potassium-loaded citric acid functionalized humic acid component is 3-15 wt% of the amount of humic acid.

7. The humic acid organic water-soluble fertilizer according to claim 1, characterized in that, The trace elements are one or more of zinc sulfate, copper sulfate, borax, and ammonium molybdate.

8. The humic acid organic water-soluble fertilizer according to claim 1, characterized in that, The composite additives include dispersants and wetting agents.

9. A humic acid organic water-soluble fertilizer according to claim 8, characterized in that, The dispersant is sodium methylene bisnaphthalene sulfonate or sodium lignin sulfonate.

10. A humic acid organic water-soluble fertilizer according to claim 8, characterized in that, The wetting agent is sodium dodecylbenzenesulfonate or sodium dodecyl sulfate.