Liquid fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a liquid fertilizer as well as a preparation method and application thereof. The preparation method of the liquid fertilizer comprises the following steps: S1, mixing potassium hydroxide, urea, a surfactant, water and biomass, stirring at 20-80 DEG C for 0.1-5 hours, and separating to obtain a biomass pretreatment solution; and S2, mixing the liquid obtained by biomass pretreatment with a preparation raw material containing biogas slurry to obtain the liquid fertilizer. The preparation raw materials of the liquid fertilizer comprise the liquid obtained through biomass pretreatment, resource utilization of biomass is facilitated, the fertilizer efficiency of the liquid fertilizer is good, and the liquid fertilizer has good application prospects.

Description

Technical Field

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

[0002] Anaerobic fermentation technology refers to the process in which organic matter (such as human and livestock excrement, straw, weeds, etc.) is decomposed and metabolized by various microorganisms under certain moisture, temperature and anaerobic conditions, and finally forms a combustible mixed gas such as methane and carbon dioxide. It is an effective means to solve the problem of large production and difficult disposal of organic solid waste (livestock and poultry excrement, kitchen waste, agricultural and forestry waste straw, etc.), and can realize the resource utilization of organic solid waste. In order to improve the fermentation effect of biomass, the biomass is often pre-treated by alkali treatment before fermentation. However, the direct discharge of the treated liquid obtained from the pre-treatment will not only cause a large amount of pollution to the water body, but also is not conducive to the resource utilization of biomass. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a liquid fertilizer, the raw material of which includes the liquid obtained by pre-treatment of biomass, which is not only conducive to the resource utilization of biomass, but also has good fertilizer effect and good application prospects.

[0004] The invention also provides a method for preparing the liquid fertilizer.

[0005] The present invention also proposes the application of the liquid fertilizer.

[0006] In a first aspect of the present invention, a method for preparing a liquid fertilizer is provided, comprising the following steps:

[0007] S1, potassium hydroxide, urea, surfactant, water and biomass are mixed, stirred at 20-80°C for 0.1-5h, separated, and a biomass pretreatment liquid is obtained;

[0008] S2, mixing the liquid obtained by biomass pretreatment with the raw material containing biogas slurry to obtain the liquid fertilizer.

[0009] Biogas slurry refers to the waste liquid rich in organic matter produced in the process of organic matter (such as human, livestock and poultry feces, straw, weeds, etc.) being decomposed and metabolized by microorganisms under certain moisture, temperature and anaerobic conditions to eventually form a combustible mixed gas such as methane and carbon dioxide. Optionally, the materials obtained by anaerobic fermentation are separated to obtain the biogas residue and biogas slurry.

[0010] The method for preparing liquid fertilizer according to the embodiment of the present invention has at least the following beneficial effects:

[0011] In the present invention, the biomass is pre-treated with a material containing potassium hydroxide, urea, and a surfactant, which can effectively dissolve part of the organic matter in the biomass material into the liquid phase, which can not only realize the extraction of the applied substances in the biomass to facilitate the improvement of the fertilizer efficiency of the liquid fertilizer, but also be beneficial to the subsequent fermentation effect of the biomass after the pre-treatment. The biogas slurry is mixed with the pre-treatment liquid to recover the nutrients in the biogas slurry into the liquid fertilizer, and further solve the potential environmental pollution problem caused by the biogas slurry produced by anaerobic fermentation.

[0012] In some embodiments of the present invention, the biomass includes at least one of wheat, rice, corn, yam, rape, cotton, sugarcane straw or switchgrass. Optionally, the energy grass includes at least one of wheat straw, rice straw, corn straw, yam straw, rape straw, cotton straw, sugarcane straw or switchgrass.

[0013] In some embodiments of the present invention, the surfactant includes at least one of tea saponin, Tween, potassium dodecyl sulfate, sodium dodecyl sulfate or polyoxyethylene fatty acid ester.

[0014] In some embodiments of the present invention, the surfactant includes tea saponin and potassium dodecyl sulfate, which is more conducive to dissolving part of the organic matter in the biomass material into the treatment liquid, and the resulting liquid fertilizer has better fertilizer efficiency.

[0015] In some embodiments of the present invention, the mass ratio of tea saponin to potassium dodecyl sulfate is 1:(0.1-5), preferably 1:(0.5-2).

[0016] In some embodiments of the present invention, in step S1, the mass ratio of potassium hydroxide, urea, surfactant and water is (0.1-10):(0.1-10):(0.01-10):100, such as (0.1-5):(0.1-5):(0.01-5):100.

[0017] In some embodiments of the present invention, in step S1, the mass ratio of potassium hydroxide to urea is 1:(0.2-5).

[0018] In some embodiments of the present invention, step S1 includes the following operations:

[0019] S1-1, taking potassium hydroxide, urea, a surfactant and water, mixing them to obtain a treatment solution;

[0020] S1-2, mixing the treated liquid with the biomass, stirring at 20-80° C. for 0.1-5 h, and separating the solid and the liquid to obtain the liquid obtained by the biomass pretreatment.

[0021] In some embodiments of the present invention, in step S1-2, the usage ratio of the biomass to the treatment liquid is 1 g:(5-30) mL, such as 1 g:(10-20) mL.

[0022] In some embodiments of the present invention, in step S1-2, the treatment liquid and the biomass are mixed and stirred, the stirring temperature is selected from 25 to 70°C, and the stirring time is selected from 0.5 to 3 hours.

[0023] In some embodiments of the present invention, in step S1-2, the biomass is crushed and then mixed with the treatment liquid. Optionally, the biomass is crushed to a particle size not coarser than 60 mesh and then mixed with the treatment liquid.

[0024] In some embodiments of the present invention, in step S1-2, after the solid-liquid separation, the liquid obtained by the biomass pretreatment and the pretreated biomass are obtained. Optionally, the pretreated biomass is subjected to anaerobic fermentation to obtain a fermentation liquid, which is separated to obtain biogas residue and biogas liquid. Further optionally, the biogas liquid is used to prepare the raw material of the liquid fertilizer.

[0025] In some embodiments of the present invention, in step S2, the mass ratio of the liquid obtained from the biomass pretreatment to the biogas slurry in the prepared raw material is 1:(0.2-5).

[0026] In some embodiments of the present invention, the preparation raw materials also include raw materials or gels for hydrogels. Optionally, the raw materials for hydrogels include but are not limited to various raw materials for hydrogels that can be generated or exist relatively stably under alkaline conditions.

[0027] Through the above implementation, the liquid fertilizer contains a hydrogel component, which has an adsorption effect on the nutrients in the liquid fertilizer. When the liquid fertilizer is used to fertilize the plants, the nutrients in the liquid fertilizer can be gradually released into the hydrogel component based on the adsorption effect of the hydrogel, thereby achieving the slow-release effect of the liquid fertilizer. Liquid fertilizer has a slow-release effect, which not only has the characteristics of long fertilizer effect and reduces the number of fertilization times, but is also more suitable for fertilizing plants that are more sensitive to fertilizer concentration, and has good application prospects.

[0028] When the raw materials for preparation are raw materials for hydrogel, the liquid obtained from the biomass pretreatment contains urea and potassium hydroxide, which is not only conducive to the formation of degradable hydrogel under alkaline conditions and reduces the additional addition of alkaline substances in the hydrogel reaction system, but also urea and potassium hydroxide are rich in N and K, which is conducive to further improving the fertilizer efficiency of liquid fertilizer.

[0029] In some embodiments of the present invention, the mass ratio of the liquid obtained by the biomass pretreatment to the raw material of the hydrogel is 100:(0.2-40).

[0030] In some embodiments of the present invention, the mass ratio of the liquid obtained by the biomass pretreatment to the gel is 100:(0.2-40).

[0031] In some embodiments of the present invention, the method for preparing the gel comprises the following steps:

[0032] Sa-1, adding isopropanol to a dispersion containing chitosan and water, adjusting the pH to 9-11 to obtain a mixed solution, adding epichlorohydrin, heating to reflux, evaporating, filtering, washing, and drying to obtain epichlorohydrin-modified chitosan;

[0033] Sa-2, adding dioxane to a 0.1-1 mol / L sodium hydroxide solution to obtain a mixed solvent, adding meglumine, mixing with the epichlorohydrin-modified chitosan obtained in Sa-1, heating to reflux, evaporating and filtering, washing, and drying to obtain meglumine-grafted chitosan;

[0034] Sa-3, adding meglumine-grafted chitosan to a mixture of polyglutamic acid and water, stirring to dissolve, adding acetic acid, stirring, washing, and drying to obtain the gel.

[0035] In some embodiments of the present invention, in Sa-1, the chitosan and water are mixed in a ratio of 0.05-0.1 g:1 mL to obtain the dispersion; and the amount of isopropanol added to the dispersion is 0.9-1.5 g / mL.

[0036] In some embodiments of the present invention, in Sa-1, the amount of epichlorohydrin added to the mixed solution is 0.1-0.5 g / mL; the heating reflux temperature is 60-65° C., and the time is 3-5 h.

[0037] In some embodiments of the present invention, in Sa-2, the amount of dioxane added to the sodium hydroxide solution is 2.2-2.6 g / mL; the amount of meglumine added to the mixed solvent is 1.9-2.3 g / mL.

[0038] In some embodiments of the present invention, in Sa-2, the heating reflux temperature is 60-65° C., and the time is 2.5-3.5 h.

[0039] In some embodiments of the present invention, in Sa-3, polyglutamic acid is mixed with water to obtain the mixture, wherein the amount of polyglutamic acid added to the water is 0.04 to 0.06 g / mL.

[0040] In some embodiments of the present invention, in Sa-3, meglumine-grafted chitosan is added to the mixture, stirred and dissolved to obtain a mixed solution I. Optionally, the amount of acetic acid added to the mixed solution is 5.6-7.2 g / mL.

[0041] In some embodiments of the present invention, step S2 comprises:

[0042] S2-b-1, taking or preparing meglumine-grafted chitosan;

[0043] S2-b-2, adding polyglutamic acid to a portion of the liquid obtained by pretreatment of the biomass, stirring and dissolving, adding meglumine-grafted chitosan, stirring and dissolving to obtain a mixed solution II;

[0044] S2-b-3, adding acetic acid into the mixed solution II, and then adding other parts of the liquid obtained from the pretreatment of the biomass and the biogas slurry, and continuing to stir to obtain liquid fertilizer.

[0045] In some embodiments of the present invention, in S2-b-2, the amount of polyglutamic acid added to the liquid obtained by biomass pretreatment is 0.04-0.06 g / mL; in S2-b-3, the amount of acetic acid added to the mixed liquid II is 5.6-7.2 g / mL.

[0046] In some embodiments of the present invention, the ratio of the sum of the mass of the meglumine-grafted chitosan and chitosan to the mass of the liquid obtained from the biomass pretreatment and the mass of the biogas slurry is (0.1-3):(1-10):(5-20).

[0047] The second aspect of the present invention provides a liquid fertilizer prepared by the above preparation method.

[0048] The third aspect of the present invention provides the use of the liquid fertilizer in growing fruits and vegetables. DETAILED DESCRIPTION

[0049] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0050] The experimental methods in the following examples without specifying specific conditions are generally carried out according to conventional conditions in the art or conditions recommended by the manufacturers; the raw materials and reagents used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets.

[0051] Example 1

[0052] This embodiment discloses a liquid fertilizer, the preparation process of which includes:

[0053] (I) Potassium hydroxide, urea, surfactant and water are mixed to obtain a treatment solution; wherein the mass ratio of potassium hydroxide, urea, surfactant and water is 1:1:0.5:100; and the surfactant is tea saponin and potassium dodecyl sulfate in a mass ratio of 1:1.

[0054] The switchgrass was crushed into 60-80 meshes, the treatment liquid and the switchgrass were mixed at a ratio of 15 mL:1 g, stirred at 30° C. for 2 h, and solid-liquid separation was performed to obtain the biomass pretreatment liquid and the pretreated switchgrass.

[0055] The pre-treated switchgrass is anaerobically fermented and separated to obtain biogas slurry.

[0056] (II) Preparation of gel, comprising:

[0057] Chitosan powder was added to water in an amount of 0.07 g / mL to obtain a chitosan dispersion, isopropanol was added to the chitosan dispersion in an amount of 1.2 g / mL, the pH was adjusted to 10 to obtain a mixed solution, epichlorohydrin was added to the mixed solution in an amount of 0.3 g / mL, heated to reflux at 60° C. for 3.5 h, evaporated and filtered, washed with water three times, washed with ethanol three times, and dried to obtain epichlorohydrin-modified chitosan;

[0058] Dioxane was added in an amount of 2.5 g / mL to a 0.8 mol / L sodium hydroxide solution, and stirred evenly to obtain a mixed solvent. Meglumine was added in an amount of 2.3 g / mL to the mixed solvent, and mixed with epichlorohydrin-modified chitosan, heated under reflux at 60° C. for 3.5 h, evaporated and filtered, washed with water three times, washed with ethanol three times, and dried to obtain meglumine-grafted chitosan;

[0059] Adding polyglutamic acid in an amount of 0.04 g / mL to water and stirring to dissolve, adding meglumine-grafted chitosan and stirring to dissolve to obtain a mixed solution, adding acetic acid in an amount of 7.2 g / mL to the mixed solution, continuing to stir, washing and drying to obtain the gel;

[0060] (III) taking gel, liquid obtained from biomass pretreatment and biogas slurry, and mixing them to obtain the liquid fertilizer, wherein the mass ratio of gel, liquid obtained from biomass pretreatment and biogas slurry is 1:3:6.

[0061] This embodiment also prepares a series of diluted liquid fertilizers, including: diluting the liquid fertilizer in this embodiment with water to 6, 7, 8, 9, and 10 times, respectively, to obtain a series of diluted liquid fertilizers, and the diluted liquid fertilizers are numbered sequentially as liquid fertilizer-6 times, liquid fertilizer-7 times, liquid fertilizer-8 times, liquid fertilizer-9 times, and liquid fertilizer-10 times.

[0062] In some other embodiments of the present invention, other degradable hydrogels (such as various commercially available hydrogels) may be used to replace the gel prepared in Example 1.

[0063] In some other embodiments of the present invention, the source of the biogas slurry may also come from the anaerobic fermentation of pig manure (or the anaerobic fermentation of biomass resources such as corn stalks, reed stalks, etc.), etc.

[0064] Example 2

[0065] This embodiment discloses a liquid fertilizer, which differs from Embodiment 1 only in that corn stalks of equal mass are used to replace switchgrass in step (I) of this embodiment.

[0066] Example 3

[0067] This embodiment discloses a liquid fertilizer, which is different from the embodiment 1 only in that the surfactant in step (I) of this embodiment is tea saponin.

[0068] Example 4

[0069] This embodiment discloses a liquid fertilizer, which differs from Embodiment 1 only in that the mass ratio of tea saponin to potassium dodecyl sulfate in step (I) of this embodiment is 1:0.2 (the total amount of surfactant is the same as that in Embodiment 1).

[0070] Example 5

[0071] This embodiment discloses a liquid fertilizer, which differs from Embodiment 1 only in that the mass ratio of tea saponin to potassium dodecyl sulfate in step (I) of this embodiment is 1:5 (the total amount of surfactant is the same as that in Embodiment 1).

[0072] Example 6

[0073] This embodiment discloses a liquid fertilizer, which is different from the embodiment 1 only in that the liquid fertilizer in this embodiment does not contain gel. Specifically, the preparation process of the liquid fertilizer in this embodiment includes:

[0074] (I) Same as Example 1.

[0075] (II) The liquid obtained by pre-treatment of biomass and biogas slurry are mixed to obtain the liquid fertilizer. The mass ratio of the liquid obtained by pre-treatment of biomass and biogas slurry is 3:6. The source of biogas slurry is the same as that in Example 1.

[0076] This embodiment also prepares a series of diluted liquid fertilizers, including: diluting the liquid fertilizer in this embodiment with water to 6, 7, 8, 9, and 10 times, respectively, to obtain a series of diluted liquid fertilizers, and the diluted liquid fertilizers are numbered sequentially as liquid fertilizer-6 times, liquid fertilizer-7 times, liquid fertilizer-8 times, liquid fertilizer-9 times, and liquid fertilizer-10 times.

[0077] Comparative Example 1

[0078] This comparative example discloses a liquid fertilizer, which differs from Example 1 only in that in step (I) of this comparative example, no surfactant is used, and the other steps are the same as Example 1.

[0079] Test example

[0080] This test example tests the performance of the biomass and liquid fertilizer obtained after pretreatment in the examples and comparative examples, specifically including:

[0081] 1. Fermentation performance test of the biomass obtained after pretreatment, including: anaerobic fermentation of the switchgrass pretreated in step (I) of Example 1 of the present invention, solid-liquid separation, and testing the content of various nutrients in the biogas slurry:

[0082] Table 1

[0083]

[0084]

[0085] 2. Rice cultivation fertilizer efficiency test:

[0086] Select high-quality rice varieties - ivory rice (Oryza sativa var. glutinosa), after rice seedlings, select seedlings with a plant height of 10 cm and transplant them into the same batch of 200g soil, set up a blank group and multiple experimental groups (including a comparative experimental group) with fertilizers, and cultivate rice in an artificial incubator at 30°C, 80% humidity and sufficient light for 4 weeks. Add 30mL of deionized water and 30mL of corresponding liquid fertilizer to the blank group, the comparative group and each experimental group every week (no fertilizer is applied to the blank group), and set up three parallel groups for each group. Among them, in the comparative experimental group, Stanley plant nutrient solution (N+P2O5+K2O≥80g / L) was diluted with water to 7 times as liquid fertilizer.

[0087] After 4 weeks of cultivation, the average plant height and average dry weight of rice in each group were tested. The test results and fertilizer information used in each experimental group are shown in Table 2 below:

[0088] Table 2 Paddy soil fertilization test results

[0089]

[0090]

[0091] 3. Fruit and vegetable cultivation fertilizer efficiency test:

[0092] 1) Tomatoes (Solanum lycopersicum L.) transplanted from nutrient soil to potted plants were selected as test fruits and vegetables, with 100 plants in each group, transplanted in the same batch of soil, and set up a blank group and multiple experimental groups with fertilizers. They were cultivated in an artificial incubator at 30°C, 80% humidity and sufficient light for 4 weeks. 30mL of deionized water and corresponding liquid fertilizer (fertilizer to soil mass ratio of 1:20) were added to the blank group, control group and each experimental group every week. No fertilizer was applied to the blank group, and three parallel groups were set up for each group. Among them, in the control group 1, Stanley plant nutrient solution (N+P2O5+K2O content ≥80g / L) was diluted with water to 7 times as liquid fertilizer.

[0093] After 4 weeks of cultivation, the average plant height growth rate of tomatoes in each group was calculated compared with that of the blank group after 4 weeks of cultivation. The results are shown in Table 3:

[0094] Table 3 Tomato fertilizer efficiency test results

[0095] Fertilizer Name Average plant height growth rate Blank Group none \ Comparison group 1 Stanley Plant Nutrition Fertilizer 31.2％ Comparison group 2 Comparative Example 1 Liquid Fertilizer - 7 times 35.2％ Experimental Group 1 Example 1 Liquid Fertilizer - 7 times 38.8％ Experimental Group 2 Example 2 Liquid Fertilizer - 7 times 37.2％ Experimental Group 3 Example 3 Liquid Fertilizer - 7 times 36.6％ Experimental Group 4 Example 4 Liquid Fertilizer - 7 Times 36.4％ Experimental Group 5 Example 5 Liquid Fertilizer - 7 Times 37.0％ Experimental Group 6 Example 6 Liquid Fertilizer - 7 times 35.9％

[0096] If there is no special explanation, the actual meaning of “about” in the present invention is that the error is allowed to be within the range of ±2%, for example, about 100 is actually 100±2%×100; “normal temperature” or “room temperature” in the present invention is about 20-30°C; “between” in the present invention includes the number itself, for example, “between 2 and 3” includes the endpoint values ​​2 and 3.

[0097] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing liquid fertilizer, It is characterized in that The steps include: S1, potassium hydroxide, urea, surfactant, water and biomass are mixed, stirred at 20-80°C for 0.1-5h, separated, and a biomass pretreatment liquid is obtained; S2, mixing the liquid obtained by biomass pretreatment with the raw material containing biogas slurry to obtain the liquid fertilizer.

2. The method for preparing the liquid fertilizer according to claim 1, It is characterized in that The biomass includes at least one of wheat, rice, corn, potato, rapeseed, cotton, sugarcane straw or switchgrass.

3. The method for preparing the liquid fertilizer according to claim 1, It is characterized in that The surfactant includes at least one of tea saponin, Tween, potassium lauryl sulfate, sodium lauryl sulfate or polyoxyethylene fatty acid ester; Preferably, the mass ratio of tea saponin to potassium dodecyl sulfate is 1:(0.1-5).

4. The method for preparing liquid fertilizer according to claim 1, It is characterized in that In step S1, the mass ratio of potassium hydroxide, urea, surfactant and water is (0.1-10):(0.1-10):(0.01-10):

100.

5. The method for preparing the liquid fertilizer according to claim 1, It is characterized in that Step S1 includes the following operations: S1-1, taking potassium hydroxide, urea, a surfactant and water, mixing them to obtain a treatment solution; S1-2, mixing the treated liquid with the biomass, stirring at 20 to 80° C. for 0.1 to 5 hours, and separating the solid and the liquid to obtain the liquid obtained by the biomass pretreatment; Preferably, in step S1-2, the ratio of the biomass to the treatment liquid is 1 g: (5-30) mL.

6. The method for preparing the liquid fertilizer according to claim 1, It is characterized in that In step S2, the mass ratio of the liquid obtained by the biomass pretreatment to the biogas slurry in the preparation raw material is 1:(0.2-5).

7. The method for preparing liquid fertilizer according to claim 1, It is characterized in that The preparation raw materials also include raw materials or gels for hydrogels; Preferably, the mass ratio of the liquid obtained by the biomass pretreatment to the gel is 100:(0.2-40).

8. The method for preparing liquid fertilizer according to claim 7, It is characterized in that The preparation method of the gel comprises the following steps: Sa-1, adding isopropanol to a dispersion containing chitosan and water, adjusting the pH to 9-11 to obtain a mixed solution, adding epichlorohydrin, heating to reflux, evaporating, filtering, washing, and drying to obtain epichlorohydrin-modified chitosan; Sa-2, adding dioxane to a 0.1-1 mol / L sodium hydroxide solution to obtain a mixed solvent, adding meglumine, mixing with the epichlorohydrin-modified chitosan obtained in Sa-1, heating to reflux, evaporating, filtering, washing, and drying to obtain meglumine-grafted chitosan; Sa-3, adding meglumine-grafted chitosan to a mixture of polyglutamic acid and water, stirring to dissolve, adding acetic acid, stirring, washing, and drying to obtain the gel.

9. A liquid fertilizer, It is characterized in that The method is prepared by the method according to any one of claims 1 to 8.

10. Use of the liquid fertilizer prepared by the method according to any one of claims 1 to 8 or the liquid fertilizer according to claim 9 in growing fruits and vegetables.

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