CN112939681A

CN112939681A - Gel microsphere based on anaerobic fermentation tail liquid and preparation method and application thereof

Info

Publication number: CN112939681A
Application number: CN202110140553.7A
Authority: CN
Inventors: 张志萍; 张全国; 赵宁; 李亚猛; 张浩睿; 艾福珂; 胡兵; 范小妮
Original assignee: Henan Agricultural University
Current assignee: Henan Agricultural University
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2021-06-11
Also published as: AU2021101074A4

Abstract

The invention is suitable for the technical field of anaerobic fermentation tail liquid treatment, and provides gel microspheres based on anaerobic fermentation tail liquid as well as a preparation method and application thereof, wherein the preparation method of the gel microspheres comprises the following steps: mixing the anaerobic fermentation tail liquid with a sodium alginate solution to obtain a mixed solution; dropping the mixed solution into CaCl₂And standing the solution, and filtering to obtain the gel microspheres. According to the invention, the anaerobic fermentation tail liquid is immobilized by a gel method, so that the nutrient elements such as nitrogen, phosphorus, potassium and the like in the anaerobic fermentation tail liquid can be immobilized, and then the immobilized nutrient elements are used in plant hydroponics to provide the nutrient elements required by growth for plants through a slow release effect.

Description

Gel microsphere based on anaerobic fermentation tail liquid and preparation method and application thereof

Technical Field

The invention belongs to the technical field of anaerobic fermentation tail liquid treatment, and particularly relates to gel microspheres based on anaerobic fermentation tail liquid as well as a preparation method and application thereof.

Background

With the vigorous development of economy, the demand for energy is continuously increasing, thereby causing serious environmental and energy problems. Nowadays, among renewable energy sources, the field of hydrogen energy is continuously developed, and hydrogen production methods are gradually changed from hydrogen production by fossil fuel to biological hydrogen production. In the biological hydrogen production method, anaerobic fermentation is mainly utilized to produce hydrogen through fermentation, and a large amount of anaerobic fermentation tail liquid can be produced through the hydrogen production through fermentation. These tail solutions contain a large amount of growth elements such as nitrogen, phosphorus, and potassium, and amino acids such as phenylalanine and proline, which are used for plant growth. If the tail liquid is treated and utilized, the environment can be protected, the purpose of waste utilization can be realized, and a nutrient source is provided for plant cultivation.

The fermentation tail liquid can be subjected to waste utilization through an immobilization technology. In the existing immobilization technology, sodium alginate is a better choice for embedding and immobilization. Sodium alginate is a byproduct of iodine and mannitol extracted from Sargassum and Brown algae, is a natural polysaccharide high molecular polymer, has good biocompatibility and low cytotoxicity, and is low in cost and easy to obtain. Sodium alginate contains-COO in its molecule^－Group, Na when divalent cation is added to aqueous solution of sodium alginate⁺Exchange with these divalent cations to convert the sodium alginate solution to hydrogel. A hydrogel is a polymer having hydrophilic groups that is capable of being swollen by water but is insoluble in water. The binding capacity of sodium alginate to multivalent cations follows the order of Pb²⁺＞Cu²⁺＞Cd²⁺＞Ba²⁺＞Sr²⁺＞Ca²⁺＞Co²⁺，Ni²⁺，Zn²⁺＞Mn²⁺. Although Pb is present²⁺And Cu²⁺Chelating ability of (2) to Ca²⁺Strong but Pb²⁺And Cu²⁺Has certain biological toxicity. Therefore, Ca can be selected when the sodium alginate hydrogel is used as a fermentation tail liquid release carrier²⁺As a cross-linking agent.

Sodium alginate solution and Ca-containing solution²⁺When the solution contacts, the calcium alginate hydrogel microspheres can be instantly gelled, so that the embedding and slow release of macromolecules can be realized by preparing the microspheres under mild conditions. The microsphere prepared from sodium alginate has excellent biological adhesion, biocompatibility and no toxic or side effect. The sodium alginate gel microspheres have the following characteristics: (1) the particle size is smaller, the strength is better, and the activity of embedded biomacromolecules can be effectively protected; (2) no biological toxicity; (3) has selectivity to element release, can prolong the release time and has ideal controlled release effect.

Research of Harbin industrial university in the aspect of hydrogen production by fermentation organisms enables China to have a niche in the field of international hydrogen production, and people such as Gaochun plum of Lanzhou university research the preparation of sodium alginate hydrogel and the application of sodium alginate hydrogel in drug release, and people such as national Zhang of renewable energy sources of Ministry of agriculture of Henan university research the technology of fixing photosynthetic bacteria by sodium alginate embedding method. At present, no research is available for treating fermentation tail liquid by using a gel method.

Disclosure of Invention

The embodiment of the invention aims to provide a preparation method of gel microspheres based on anaerobic fermentation tail liquid, and aims to solve the problems in the background art.

The embodiment of the invention is realized in such a way that a preparation method of gel microspheres based on anaerobic fermentation tail liquid comprises the following steps:

mixing the anaerobic fermentation tail liquid with a sodium alginate solution to obtain a mixed solution;

dropping the mixed solution into CaCl₂And standing the solution, and filtering to obtain the gel microspheres.

As another preferable scheme of the embodiment of the invention, the mass concentration of the sodium alginate solution is 1-3%.

As another preferable scheme of the embodiment of the invention, the mass concentration of the sodium alginate solution is 1.5-2.5%.

As another preferable scheme of the embodiment of the invention, the anaerobic fermentation tail liquid is at least one of alfalfa dark fermentation tail liquid, cow dung corn straw mixed light fermentation tail liquid, corn straw biochar mixed light fermentation tail liquid, sludge corn straw dark fermentation tail liquid and corn cob light fermentation tail liquid.

As another preferable scheme of the embodiment of the invention, the volume ratio of the sodium alginate solution to the anaerobic fermentation tail solution is (6-8) to (2-4).

As another preferred embodiment of the invention, said CaCl₂The mass concentration of the solution is 1-3%.

As another preferred embodiment of the invention, said CaCl₂The mass concentration of the solution is 1.5-2.5%.

Another object of the embodiments of the present invention is to provide a gel microsphere prepared by the above preparation method.

As another preferable scheme of the embodiment of the invention, the diameter of the gel microsphere is 3-5 mm.

The other purpose of the embodiment of the invention is to provide an application of the gel microspheres in plant fertilization.

Numerous studies have shown that amino acids are an essential part of plant growth. The glycine (Gly) can enhance the absorption of phosphorus and potassium elements by crops and has a unique promoting effect on plant photosynthesis. Tyrosine (Tyr) regulates the maintenance of root tips, root cells in plants. Phenylalanine (Phe) can participate in disease resistance of plants, and disease resistance of the plants is improved. Proline (Pro) plays an important role in plant development, depending on the developmental stage of the plant, the type of organ. Serine (Ser) affects plant germination and cell tissue differentiation. Arginine (Arg) has the function of storing nitrogen element and can participate in the physiological and biochemical processes of plant growth and development, stress resistance and the like. Therefore, the gel microspheres prepared from the anaerobic fermentation tail liquid can release a large amount of amino acid in the slow release process, and the quality of the nutrient solution is greatly improved.

According to the preparation method of the gel microspheres based on the anaerobic fermentation tail liquid, provided by the embodiment of the invention, the anaerobic fermentation tail liquid is immobilized through a gel method, so that nutrient elements such as nitrogen, phosphorus, potassium and the like in the anaerobic fermentation tail liquid can be immobilized, and then the gel microspheres are used in plant hydroponics and provide nutrient elements required by growth for plants through a slow release effect.

Drawings

FIG. 1 is a comparison graph of nutrient element content of sustained-release nutrient solution of gel microspheres obtained by forward-drop and reverse-drop immobilization of five fermentation tail solutions. In FIG. 1, (a) is a graph comparing the total nitrogen content; (b) a P content comparison graph is shown; (c) is a K content comparison graph; (d) a graph comparing Mg content; (e) the Ca content is shown in the graph.

FIG. 2 is a comparison graph of main amino acids of the sustained-release nutrient solution of gel microspheres obtained by forward-drop and reverse-drop immobilization of five fermentation tail solutions. In FIG. 2, (a) is a comparison of Phe content; (b) pro content comparison graph; (c) the Arg content is shown in the graph.

FIG. 3 shows the use of CaCl at different concentrations₂Size comparison graph of gel microspheres prepared from the solution.

FIG. 4 shows the use of CaCl at different concentrations₂The mass comparison curve of the gel microspheres prepared from the solution is shown.

FIG. 5 shows the use of different concentrations of CaCl₂The number of gel microspheres produced from the solution is compared to the graph.

FIG. 6 shows CaCl at various concentrations₂The gel effect of the solution is compared with the figure. In FIG. 6, (a) is 1% CaCl₂A solution; (b) is 2% of CaCl₂And (3) solution.

FIG. 7 is a graph comparing the gel effect of sodium alginate solutions of different concentrations. In fig. 6, (a) is a 1% sodium alginate solution; (b) is a 2% sodium alginate solution; (c) is a 3% sodium alginate solution.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The following examples and experimental examples used alfalfa dark fermentation tail liquid, cow dung corn straw mixed light fermentation tail liquid, corn straw biochar mixed light fermentation tail liquid, sludge corn straw dark fermentation tail liquid, and corn cob light fermentation tail liquid, which come from renewable energy open laboratories of the ministry of agriculture of the southern Henan university. Wherein, the fermentation tail liquid is taken out from the hydrogen production reaction bottle, put into a 100mL centrifuge tube, symmetrically put into a centrifuge, and centrifuged for 5min at the rotating speed of 6000 r/min. After centrifugation, the supernatant is put into a 100mL beaker and sealed by a preservative film for later use.

In addition, sodium alginate solution and CaCl as embedding materials used in the following examples and experimental examples₂The solution was prepared and used as follows.

Sodium alginate solution: weighing sodium alginate powder by using an electronic balance, putting the sodium alginate powder into a 100mL beaker, adding distilled water to prepare sodium alginate solutions with three concentrations of 1%, 1.5%, 2%, 2.5% and 3%, putting the beaker into a water bath kettle, stirring and thermally dissolving until the sodium alginate powder is completely dissolved, and taking out the beaker from the water bath kettle for later use.

CaCl₂Solution: weighing CaCl by using an electronic balance₂Placing the granules into a 500mL beaker, adding distilled water to prepare 10%, 8%, 6%, 4%, 2.5%, 2%, 1.5% and 1% CaCl concentration₂The solution was stirred with a glass rod until CaCl was formed₂The particles were completely dissolved.

Example 1

The embodiment provides a preparation method of gel microspheres based on anaerobic fermentation tail liquid, which comprises the following steps:

s1, accurately measuring 2mL of dark alfalfa fermentation tail liquid and 8mL of sodium alginate solution with the mass concentration of 1% by using a liquid transfer gun, putting the dark alfalfa fermentation tail liquid and the 8mL of sodium alginate solution into a beaker, and shaking and oscillating the solution to fully mix the dark alfalfa fermentation tail liquid and the sodium alginate solution to obtain a mixed solution.

S2, extracting the mixed solution by using a 10mL needle tube, and uniformly dripping enough CaCl with the mass concentration of 1%₂Standing the solution for 2h, and filtering to obtain the gel microspheres.

Example 2

s1, accurately measuring 4mL of cow dung-corn straw mixed light fermentation tail liquid and 6mL of sodium alginate solution with the mass concentration of 3% by using a liquid transfer gun, putting the mixture and the sodium alginate solution into a beaker, and shaking and oscillating the mixture to fully mix the mixture to obtain mixed liquid.

S2, extracting the mixed solution by using a 10mL needle tube, and uniformly dripping enough CaCl with the mass concentration of 3%₂Standing the solution for 2h, and filtering to obtain the gel microspheres.

Example 3

s1, accurately measuring 2.5mL of the corn straw biochar mixed light fermentation tail liquid and 7.5mL of sodium alginate solution with the mass concentration of 1.5% by using a liquid transfer gun, putting the mixture into a beaker, and shaking and oscillating the mixture to fully mix the mixture to obtain mixed liquid.

S2, extracting the mixed solution by using a 10mL needle tube, and uniformly dripping enough CaCl with the mass concentration of 2.5%₂Standing the solution for 2h, and filtering to obtain the gel microspheres.

Example 4

s1, accurately measuring 3.5mL of sludge corn straw dark fermentation tail liquid and 6.5mL of sodium alginate solution with the mass concentration of 2.5% by using a liquid transfer gun, putting the mixture into a beaker, and shaking and oscillating the beaker to fully mix the mixture to obtain mixed liquid.

S2, drawing the mixture with a 10mL syringe, and dropping the mixture uniformlyUntil enough CaCl with the mass concentration of 1.5 percent is obtained₂Standing the solution for 2h, and filtering to obtain the gel microspheres.

Example 5

s1, accurately measuring 3mL of corncob light fermentation tail liquid and 7mL of sodium alginate solution with the mass concentration of 2% by using a liquid transfer gun, putting the corncob light fermentation tail liquid and the 7mL of sodium alginate solution into a beaker, and shaking and oscillating the mixture to fully mix the corncob light fermentation tail liquid and the sodium alginate solution to obtain a mixed solution.

S2, extracting the mixed solution by using a 10mL needle tube, and uniformly dripping enough CaCl with the mass concentration of 2%₂Standing the solution for 2h, and filtering to obtain the gel microspheres.

Example 6

s1, accurately measuring 1mL of dark alfalfa fermentation tail liquid, 2mL of cow dung-corn straw mixed light fermentation tail liquid and 7mL of sodium alginate solution with the mass concentration of 2% by using a liquid transfer gun, putting the mixture into a beaker, and shaking and oscillating the mixture to fully mix the mixture to obtain mixed liquid.

Example 7

s1, accurately measuring 1mL of dark alfalfa fermentation tail liquid, 1mL of sludge corn straw dark fermentation tail liquid, 1mL of corncob light fermentation tail liquid and 7mL of sodium alginate solution with the mass concentration of 2% by using a liquid transfer gun, putting the mixture into a beaker, and shaking and oscillating the beaker to fully mix the mixture to obtain mixed liquid.

S2, extracting the mixed solution by using a 10mL needle tube, and uniformly dripping enough CaCl with the mass concentration of 2%₂In solutionStanding for 2h, and filtering to obtain the gel microsphere.

Experimental example:

first, experiment method

1. Gel fixation experiments of five fermentation broths:

when using sodium alginate and Ca²⁺When the aqueous solution is used as a carrier for embedding fermentation tail liquid, there are generally three methods: the forward dropping method, the reverse dropping method and the in-situ release method. The normal dropping method is to directly mix sodium alginate and fermentation tail liquid and drop Ca-containing solution²⁺In aqueous solution, Ca²⁺The gel particles are permeated from outside to inside, and the crosslinking density of the outer layer of the gel particles is higher. The back-drop method is to add Ca²⁺Dripping water solution into the mixed solution of sodium alginate and fermentation tail solution, and adding Ca²⁺The gel particles are permeated from inside to outside, and the crosslinking density of the inner layer of the gel particles is higher. The in situ release method generally adopts calcium carbonate (CaCO)₃) Or calcium ethylene diamine tetraacetic acid (Ca-EDTA) and Gluconolactone (GDL) complex system as calcium ion source, wherein H is slowly released when Gluconolactone (GDL) is dissolved⁺,H⁺Will handle CaCO₃Ca in (1)²⁺Is released and then forms a gel with the sodium alginate. The in-situ release method is complicated, so the experiment adopts a forward dropping method and a reverse dropping method.

The positive dropping method comprises the following steps: accurately measuring 3mL of fermentation tail liquid and 7mL of 3% sodium alginate solution by using a liquid transfer gun, putting the fermentation tail liquid and the 7mL of 3% sodium alginate solution into a beaker, shaking and oscillating the mixture to fully mix the fermentation tail liquid and the 3% sodium alginate solution, then extracting the mixed solution by using a 10mL needle tube, and uniformly dropping enough 10% CaCl₂Standing the solution for 2h, filtering out gel microspheres, and standing for later use.

The reverse dropping method comprises the following steps: accurately measuring 3mL of fermentation tail liquid and 7mL of 3% sodium alginate solution by using a liquid transfer gun, putting the fermentation tail liquid and the 7mL of 3% sodium alginate solution into a beaker, shaking and oscillating the mixture to fully mix the fermentation tail liquid and the 7mL of 3% sodium alginate solution, and then extracting 10% CaCl by using a 10mL needle tube₂And uniformly dripping the solution into the mixed solution of the fermentation tail liquid and the sodium alginate, standing for 2 hours, filtering out the formed gel, and standing for later use.

And (3) respectively putting the formed gel into 150mL conical flasks, adding a proper amount of distilled water, sealing the conical flasks with a preservative film, standing for 7d, and then measuring the content of each element and amino acid in the water. And (4) uniformly putting the gel into a black night cabbage water culture frame, adding tap water, and performing water culture on the black night cabbage.

2. Optimization experiment of embedding carrier concentration:

in previous sodium alginate gel studies, most were performed with 3% sodium alginate solution concentration in CaCl₂The concentration of the solution is 10 percent or even higher, and the concentration of the two carriers is reduced, so that the fixing effect and the material utilization of the fermentation tail solution are optimized.

CaCl₂Solution concentration optimization: fixing the concentration of sodium alginate solution to 3%, weighing 3mL of fermentation tail liquid and 7mL of sodium alginate solution, mixing thoroughly, and dripping enough CaCl with concentration of 10%, 8%, 6%, 4%, 2%, 1% with needle tube₂In the solution, the molding condition of the gel microspheres is observed, and the quantity, the size and the quality of the gel spheres are measured.

Optimizing the concentration of the sodium alginate solution: fixing CaCl₂Weighing 7mL of sodium alginate solution with concentration of 3%, 2% and 1%, mixing with 3mL of fermentation tail solution, and sequentially dropping 2% Ca Cl₂In the solution, the molding condition of the gel microspheres is observed, and the quantity, the size and the quality of the gel spheres are measured.

Second, results and analysis

1. Five fermentation tail liquid forward-dropping and backward-dropping slow release effects

1.1 analysis of nutrient elements in the sustained-release nutrient solution

From the forming effect, the gel dripped in the forward direction can form uniform micro-rubber balls, so that the gel balls are convenient to separate and slowly release for use, and the gel dripped in the reverse direction is converged into a rubber block, so that the gel blocks are not beneficial to separating and using. Specifically, as shown in table 1 and fig. 1, in fig. 1: (a) the content of nitrogen element in the slow-release nutrient solution which is dripped into the fermentation tail liquid in the forward direction in the figure is 10-20 times higher than that of the slow-release nutrient solution which is dripped into the fermentation tail liquid in the reverse direction in the figure, (b) the content of phosphorus element in the figure is basically not greatly different, (c) the content of potassium element in the figure is 20-30 times higher than that of the slow-release nutrient solution which is dripped into the fermentation tail liquid in the reverse direction in the figure, and (d) the content of magnesium element in the figure is 5-15 times higher than that; (e) in the figure, the content of calcium element in the nutrient solution is about 60 times higher than that of calcium element in the nutrient solution in the forward direction, only a small part of the calcium element is released from fermentation tail liquid, most of the calcium element is decomposed and released by calcium alginate gel, and the faster the calcium element is released, the more unstable the gel forming is, thus proving that the sustained-release effect of the gel block formed by forward dropping is better than that of the gel block formed by reverse dropping. Therefore, the forward dropping is better than the reverse dropping in the forming effect, and the nutrient solution formed by slow release has higher nutrient element content. From the water culture effect of the nightly cabbage, the germination rate of the cabbage seeds dropped in the forward direction is obviously higher than that of the cabbage seeds dropped in the reverse direction.

TABLE 1 nutrient element content of five fermentation tail liquid sustained-release nutrient solutions

1.2 analysis of amino acid content in the sustained-release nutrient solution

The contents of the main amino acids after the five fermentation tail liquid gels are slowly released are shown in a table 2 and a figure 2, wherein in the figure 2: (a) the Phe content in the drawing is 10-60 times higher than that in the reverse dropping, the releasable Phe after the alfalfa fermentation tail liquid is dropped in the forward direction even reaches 6.661mg/L, (b) the Pro content in the drawing is more than 10 times higher than that in the reverse dropping, and (c) the Arg content in the drawing is 2-10 times higher than that in the reverse dropping. It can be obviously seen that the gel microspheres prepared by the forward dropping method have higher amino acid content in nutrient liquid slowly released than gel blocks prepared by the reverse dropping method, and the three amino acids play a vital role in the growth and development of plants, the utilization of nitrogen elements and the disease resistance, so that the forward dropping method is more favorable for the fixation and utilization of fermentation tail liquid.

TABLE 2 main amino acid content of five fermentation tail liquid sustained-release nutrient solutions

2. Influence of embedding carriers with different solution concentrations on gel microsphere formation

As shown in FIGS. 3 to 5, it can be seen that with CaCl₂The concentration of the solution changes, the diameter of the rubber balls changes slightly, the mass of the rubber balls is kept between 0.02g and 0.04g within 3-5 mm, the difference is only 0.0135g at most, the number of the rubber balls is between 220 and 300, and the difference is not large, so that CaCl can be obtained₂The solution concentration has little effect on the rubber ball.

As shown in FIG. 6, it can be seen that (a) of FIG. 6 is CaCl₂When the concentration of the solution is 1%, the rubber ball is irregular and elliptical and can sink into the bottom of the beaker, and the forming effect is poor. FIG. 6 (b) is CaCl₂When the concentration of the solution is 2%, the rubber ball is in a regular round shape, and can flow when stirred, so that the forming effect is good. Therefore, CaCl is selected₂The concentration of the solution is optimal to 2 percent, the forming effect is good, and a large amount of raw materials can be saved.

As shown in FIG. 7, it can be seen that FIG. 7 (a) is a diagram in which a 1% sodium alginate solution is mixed with a fermentation tail solution, and then 2% CaCl is added dropwise₂In the solution, the forming effect is very poor, and basically no balls are formed, and the figure (b) of figure 7 is that after 2% sodium alginate solution is mixed with fermentation tail liquid, 2% CaCl is dropped₂In the solution, the forming effect is better, the formed colloidal spheres have uniform size, and the figure (c) of figure 7 is that after 3 percent sodium alginate solution is mixed with fermentation tail liquid, 2 percent CaCl is dripped in₂In the solution, it was found that the gel beads were formed, but the forming effect was not as good as that in FIG. 7 (b), and therefore, the sodium alginate solution was selected to be 2% at best.

Third, conclusion

The invention creatively provides a method for preparing calcium alginate gel balls from fermentation tail liquid, and growth elements such as nitrogen, phosphorus, potassium and the like in the fermentation tail liquid are immobilized, so that the slow-release nutrient solution for plant growth is prepared. Not only realizes the harmless treatment of the anaerobic fermentation tail liquid and protects the environment, but also achieves the purpose of resource utilization of the fermentation tail liquid.

According to the experiment, after the sodium alginate solution and the fermentation tail liquid are mixed, CaCl is positively dropped₂The solution can make the gel microsphere formed uniformly, is favorable for statistical measurement and slow release fertilization, and the slow release nutrient solution dripped in the forward directionThe contents of nutrient elements and amino acid are obviously higher than those of the reverse dripping. Therefore, the sodium alginate is used for fixing the fermentation tail liquid by adopting a forward dropping method, and the high-quality slow-release nutrient solution can be obtained.

Under the condition of fixed concentration of sodium alginate solution, CaCl₂The diameter, the quality and the quantity of the rubber balls are not greatly influenced by the concentration change of the solution, the medicine is greatly wasted due to the fact that the CaCl2 solution with high concentration can be formed, and CaCl with the concentration of 1 percent₂The forming effect of the solution is poor, so that CaCl with the concentration of 2 percent is selected₂The solution is optimal, the forming effect is good, and the raw materials can be saved.

Because the sodium alginate is directly mixed with the fermentation tail liquid, the concentration of the sodium alginate can generate great influence on the gel ball forming. Experiments show that the 1% sodium alginate solution has extremely poor forming effect and basically no balls, the 3% sodium alginate solution can be formed but has poor effect and unobvious forming, and the gel microspheres formed by the 2% sodium alginate solution are relatively uniform and have better integral forming effect.

In conclusion, after the 2% sodium alginate solution is mixed with the fermentation tail solution, 2% CaCl is positively dropped₂The forming effect and the slow release effect in the solution are optimal. Compared with the previous research, the method is an ultra-low concentration immobilization method, can ensure the utilization value of the fermentation tail liquid, reduces the dosage of reagents and saves a large amount of experimental medicines.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A preparation method of gel microspheres based on anaerobic fermentation tail liquid is characterized by comprising the following steps:

2. The preparation method of the gel microsphere based on the anaerobic fermentation tail solution as claimed in claim 1, wherein the mass concentration of the sodium alginate solution is 1-3%.

3. The preparation method of the gel microsphere based on the anaerobic fermentation tail solution as claimed in claim 2, wherein the mass concentration of the sodium alginate solution is 1.5-2.5%.

4. The method for preparing the gel microspheres based on the anaerobic fermentation tail solution according to claim 1, wherein the anaerobic fermentation tail solution is at least one of alfalfa dark fermentation tail solution, cow dung corn stalk mixed light fermentation tail solution, corn stalk biochar mixed light fermentation tail solution, sludge corn stalk dark fermentation tail solution and corn cob light fermentation tail solution.

5. The method for preparing the gel microspheres based on the anaerobic fermentation tail solution as claimed in any one of claims 1 to 4, wherein the volume ratio of the sodium alginate solution to the anaerobic fermentation tail solution is (6-8) to (2-4).

6. The method for preparing the gel microspheres based on the anaerobic fermentation tail liquid as claimed in claim 1, wherein the CaCl is added₂The mass concentration of the solution is 1-3%.

7. The method for preparing the gel microspheres based on the anaerobic fermentation tail liquid as claimed in claim 6, wherein the CaCl is added₂The mass concentration of the solution is 1.5-2.5%.

8. Gel microspheres prepared by the preparation method of any one of claims 1 to 7.

9. The gel microsphere of claim 8, wherein the diameter of the gel microsphere is 3-5 mm.

10. Use of the gel microspheres according to claim 8 or 9 in the fertilization of plants.