Aquaculture water environment restoration agent and preparation method thereof

Abstract

The invention relates to the technical field of aquaculture, in particular to an aquaculture water environment repairing agent and a preparation method thereof, and the repairing agent is composed of a modified biochar composite material, chlorella microspheres, a cross-linking agent and a microbial compound inoculant. The modified biochar composite material is prepared through the steps of mixing attapulgite and biomass raw materials, performing acid activation, performing pyrolysis and the like, and tannic acid is used for further modification so as to enhance the adsorption capacity; the chlorella microspheres are prepared from sodium alginate and a CaCl2 solution, and have good suspension property and stability; the microbial complex microbial inoculant contains various beneficial bacteria, and can decompose organic matters and reduce the content of ammonia nitrogen and nitrite; the components of the repairing agent are combined through the cross-linking agent to form particles, so that the repairing agent is convenient to put and recycle. The repairing agent disclosed by the invention has efficient pollutant removal capacity, and can be used for remarkably improving the water quality of aquatic water, improving the transparency of the water, increasing dissolved oxygen and promoting the health and stability of an aquatic ecosystem.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture, and in particular to an aquaculture water environment repair agent and a preparation method thereof. Background Art

[0002] In aquaculture, the high stocking density and large amounts of feed required for aquatic animals lead to a significant accumulation of nitrogen-containing organic matter, such as leftover bait, animal and plant excrement, and dead bodies, in aquaculture waters. Furthermore, untreated aquaculture wastewater, as well as industrial and domestic sewage, is discharged or washed into aquaculture waters via rainwater, causing excessive levels of pollutants such as ammonia nitrogen, nitrites, and heavy metals. These pollutants are also accompanied by organic contaminants such as hormones, antibiotics, and colored dyes. These pollutants are characterized by high discharge volumes, long residence times in water, high levels of harmful substances, and resistance to degradation. They easily accumulate in organisms, causing serious and irreversible impacts on human health and the environment, and are difficult to remove through self-purification processes in the water. This leads to a series of problems, such as high concentrations of ammonia nitrogen or nitrites leading to the proliferation of harmful bacteria and pathogens. This, in turn, deteriorates the health of farmed animals like fish and shrimp, reduces their ability to withstand stress, and makes them susceptible to pathogenic invasion, leading to widespread outbreaks of aquatic diseases. Therefore, the search for efficient, environmentally friendly, and low-cost water pollution remediation technologies is urgent.

[0003] Biochar (BC), a carbon material made from the pyrolysis of biomass, offers unique advantages for pollutant removal due to its porosity, high surface area, and stability. However, conventional powdered biochar suffers from its small particle size and light weight, making it susceptible to diffusion in water bodies and causing secondary contamination. Separation from the surrounding media typically requires centrifugation and filtration, limiting its application in water remediation.

[0004] Microbial remediation, as a water remediation technology based on ecological principles, offers natural, self-repairing, long-lasting, and safe properties. However, its applicability is limited. Different microorganisms have the ability to degrade specific pollutants, and their effectiveness against heavy metals is more limited. Furthermore, the immobilization and release of microorganisms are key factors influencing their effectiveness. While immobilized microorganisms can improve their stability and facilitate recovery and reuse, the limited carrier structure reduces their contact efficiency. Free microorganisms, on the other hand, are susceptible to environmental disturbances and difficult to recover.

[0005] Therefore, based on the limitations of the above-mentioned related technologies, there is an urgent need to develop a new aquaculture water environment remediation agent that can effectively combine the high-efficiency adsorption performance of biochar and the degradation ability of microorganisms, while overcoming the respective shortcomings of both, so as to provide a practical solution to the problem of aquaculture water pollution. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to propose an aquaculture water environment remediation agent that can effectively adsorb and degrade ammonia nitrogen, nitrite heavy metals and other organic pollutants in aquaculture water, while improving the stability and recovery efficiency of microorganisms and reducing secondary pollution.

[0007] Based on the above objectives, the present invention provides an aquaculture water environment repair agent and a preparation method thereof.

[0008] An aquaculture water environment repair agent comprises the following preparation steps:

[0009] S1: Mix the biomass raw material and attapulgite in proportion, pass through a 100-mesh sieve, soak in 3% dilute hydrochloric acid for 2-3 hours, with a solid-liquid mass ratio of 1:5, filter, wash with deionized water until neutral, and dry to obtain a mixture A;

[0010] S2: Add mixture A, FeSO4˙7H2O, and NiSO4˙6H2O into deionized water, mix well, and dry to obtain mixture B. Place mixture B in a programmed temperature tube furnace and heat to 450°C at a heating rate of 3-5°C / min under nitrogen protection. Keep warm for 100-120 min, wash, and dry to obtain a biochar composite material.

[0011] S3: adding the biochar composite material to the tannic acid solution, stirring for 6-8 hours, and filtering to obtain the modified biochar composite material;

[0012] S4: Cultivate Chlorella vulgaris using BG-11 medium under the conditions of light intensity of 2000-3000 lx and temperature of 25-30 °C until the cell density reaches 1.5×10 8 -3.0×10 8 cells / ml. A Chlorella algae solution was obtained, and the Chlorella algae solution and sodium alginate solution were mixed in a 1:1 ratio by volume. The mixture was stirred for 10-15 minutes at a stirring speed of 200-500 rpm. A CaCl2 solution was added dropwise in the same volume as the sodium alginate solution. The mixture was allowed to stand and solidify for 20-30 minutes, and filtered to obtain Chlorella microspheres.

[0013] S5: mixing Bacillus subtilis agent, Nitrosomonas agent, Nitrobacter agent, glucose, potassium fulvate, potassium dihydrogen phosphate, glycerol and water in proportion, and stirring evenly to obtain a microbial composite agent;

[0014] S6: Mix the modified biochar composite material with the microbial composite agent, stir at a speed of 30-50 rpm for 30-40 minutes, add a cross-linking agent and stir for 10-15 minutes, add Chlorella microspheres and stir for 10-15 minutes to obtain a mixture C, transfer the mixture C to a granulator to prepare granules, control the particle size to 0.3-1 mm, freeze-dry the granules to obtain an aquaculture water environment remediation agent.

[0015] Preferably, the biomass raw material is any one of peanut shells, rice husks, and wheat straw.

[0016] Preferably, the mass ratio of the biomass raw material, attapulgite, FeSO4˙7H2O, NiSO4˙6H2O, and deionized water is 20:5-10:9-10:1-2:100.

[0017] Preferably, the microbial composite agent comprises Bacillus subtilis agent, Nitrosomonas agent, Nitrobacter agent, glucose, potassium fulvate, potassium dihydrogen phosphate, glycerol and water in a mass ratio of 1:1-1.5:1-1.5:1.5-2:0.3-0.5:0.5-0.8:0.8-1:2.3-3.2 in parts by weight.

[0018] The Bacillus subtilis decomposes organic matter in the water by secreting extracellular enzymes, converting it into small molecules and providing nutrition for other microorganisms; Nitrosomonas oxidizes ammonia nitrogen into nitrite, and Nitrobacter further oxidizes nitrite into nitrate, thereby reducing the content of ammonia nitrogen and nitrite in the water and reducing the pollution of water bodies by toxic substances. In addition, Chlorella absorbs carbon dioxide and releases oxygen through photosynthesis, increasing the dissolved oxygen content in the water body and improving the water quality environment. At the same time, it provides oxygen support for the Bacillus subtilis agent, Nitrosomonas agent, and Nitrobacter agent, promotes their metabolic activities, forms a synergistic effect, and jointly maintains the ecological balance of the water body.

[0019] Preferably, the bacterial content of the Nitrosomonas bacteria agent and the Nitrobacter bacteria agent is 1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 The bacterial content of Bacillus subtilis inoculum is 5×10 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 .

[0020] Preferably, the cross-linking agent is any one or more of glutaraldehyde, chitosan, gelatin, and polyvinyl alcohol.

[0021] Preferably, the mass fraction of the tannic acid solution is 4%-6%. Tannic acid is a polyphenol compound with a complex structure, containing a large number of hydroxyl groups and phenolic hydroxyl groups. It reacts with heavy metals such as Pb through complexation. 2+ 、Cd 2+ It quickly combines to form a stable complex, significantly improving adsorption efficiency in the short term. This complexation can fix heavy metal ions from the water, thereby achieving their removal. In addition, because tannic acid molecules are rich in hydroxyl and phenolic hydroxyl groups, they can connect the particles of the aquatic environment remediation agent together through a bridging effect to form flocs. The hydrophobic part of tannic acid can promote the formation and stability of flocs, making the particles inside the flocs more tightly combined and less likely to be dispersed by water flow, facilitating the recovery and reuse of the aquatic environment remediation agent.

[0022] Preferably, the mass fraction of the sodium alginate solution is 3%. Sodium alginate is a natural polysaccharide with good gelation, stability, and biocompatibility. It protects microbial cells and subsequently forms a stable gel structure when cross-linked with calcium ions, wrapping the Chlorella cells and fixing the cells.

[0023] Preferably, the mass fraction of the CaCl2 solution is 1%-2%, and the excess Ca 2+ Cross-linked with sodium alginate to form a dense gel network, which limits light penetration, inhibits photosynthesis and oxygen release of Chlorella vulgaris, reduces dissolved oxygen levels, and at the same time, Ca 2+ Compete with heavy metal ions for adsorption sites, weakening the adsorption efficiency of the remediation agent on pollutants; while Ca 2+ When it is insufficient, the gel network becomes sparse, affecting the fixation of microorganisms and Chlorella, thereby reducing the efficiency of pollutant removal.

[0024] Beneficial effects of the present invention:

[0025] 1. The aquaculture water environmental remediation agent prepared by this invention has a highly efficient pollutant removal capability. Through the synergistic effect of the modified biochar composite, Chlorella microspheres, and a microbial composite agent, it can significantly reduce ammonia nitrogen, nitrite, heavy metals, and other organic pollutants in aquaculture water. The porous structure and surface functional groups of the modified biochar composite, combined with the complexation effect of tannic acid, enhance its adsorption capacity for pollutants. The various bacterial agents in the microbial composite agent can decompose organic matter and reduce ammonia nitrogen and nitrite levels. Chlorella absorbs carbon dioxide through photosynthesis and releases oxygen, further improving water quality.

[0026] 2. The colloidal suspension formed by the repair agent in water is viscous and can synergize with tannic acid to form a stable floc structure. This floc structure not only strengthens the binding force between the repair agent particles, making them more tightly bound together and less susceptible to water flow, but also facilitates the recovery and reuse of the repair agent.

[0027] 3. The biomass raw materials used in this invention are all agricultural waste, which is widely available and low-cost, achieving resource utilization of waste, with good economic and sustainable properties. The repair agent does not produce harmful byproducts during use and can be recycled and reused using tools such as magnets, avoiding the secondary pollution problems that may be caused by traditional repair agents, and is environmentally friendly. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0029] The Bacillus subtilis in the examples is derived from the China Center for Type Culture Collection, with a collection number of CCTCC No: M2011443.

[0030] The Nitrosomonas in the examples is from China General Microorganism Culture Collection Center with the collection number CGMCC 11865.

[0031] The Nitrobacter in the examples is from China Center for Type Culture Collection, with a collection number of CCTCC NO: M2014203.

[0032] Embodiment 1:

[0033] An aquaculture water environment repair agent comprises the following preparation steps:

[0034] S1: Mix 40 g peanut shells and 10 g attapulgite, pass through a 100-mesh sieve, soak in 3% dilute hydrochloric acid for 2 h at a solid-liquid mass ratio of 1:5, filter, wash with deionized water until neutral, and dry to obtain mixture A;

[0035] S2: Mixture A, 18 g FeSO4˙7H2O, and 2 g NiSO4˙6H2O were added to 100 g deionized water, mixed well, and dried to obtain mixture B. Mixture B was placed in a programmed temperature tube furnace and heated to 450°C at a heating rate of 3°C / min under nitrogen protection. The mixture was kept warm for 100 min, washed, and dried to obtain a biochar composite material.

[0036] S3: adding the biochar composite material to a 4% tannic acid solution, stirring for 6 h, and filtering to obtain a modified biochar composite material;

[0037] S4: Under the conditions of light intensity of 2000 lx and temperature of 25 °C, the Chlorella vulgaris was cultured using BG-11 medium until the cell density reached 1.5 × 10 8 -3.0×10 8 cells / ml, to obtain a Chlorella algae solution, the Chlorella algae solution was mixed with a 4% sodium alginate solution at a volume ratio of 1:1, stirred for 10 minutes at a stirring speed of 500 rpm, and a 1% CaCl2 solution was added dropwise, with the volume of the CaCl2 solution being the same as that of the sodium alginate solution. The solution was allowed to stand and solidify for 20 minutes, and filtered to obtain Chlorella microspheres;

[0038] S5: 1g of Bacillus subtilis inoculum (5×10 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1g Nitrosomonas bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1g Nitrobacter agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.5 g of glucose, 0.3 g of potassium fulvic acid, 0.5 g of potassium dihydrogen phosphate, 0.8 g of glycerol and 2.3 g of water were mixed and stirred to obtain a microbial composite agent;

[0039] S6: Mix 50g of modified biochar composite material with 10g of microbial composite agent, stir at 30rpm for 30min, add 2g of glutaraldehyde, 0.5g of chitosan, and 0.5g of polyvinyl alcohol and stir for 15min, add 22g of Chlorella microspheres and stir for 10min to obtain mixture C, transfer mixture C to a granulator to make granules, control the particle size to 0.3-1mm, freeze-dry the granules to obtain an aquaculture water environment remediation agent.

[0040] Example 2:

[0041] An aquaculture water environment repair agent comprises the following preparation steps:

[0042] S1: 40 g of rice husk and 15 g of attapulgite were mixed, passed through a 100-mesh sieve, and soaked in 3% dilute hydrochloric acid for 2.5 h at a solid-to-liquid mass ratio of 1:5. The mixture was filtered, washed with deionized water until neutral, and dried to obtain a mixture A.

[0043] S2: Add mixture A, 19 g FeSO4˙7H2O, and 3 g NiSO4˙6H2O to 100 g deionized water, mix well, and dry to obtain mixture B. Place mixture B in a programmed temperature tube furnace and heat to 450°C at a heating rate of 4°C / min under nitrogen protection. Keep warm for 110 min, wash, and dry to obtain a biochar composite material.

[0044] S3: adding the biochar composite material to a 5% tannic acid solution, stirring for 7 h, and filtering to obtain a modified biochar composite material;

[0045] S4: Under the conditions of light intensity of 2500 lx and temperature of 25 °C, the Chlorella vulgaris was cultured using BG-11 medium until the cell density reached 1.5 × 10 8 -3.0×10 8 cells / ml, to obtain a Chlorella algae solution, the Chlorella algae solution was mixed with a 3% sodium alginate solution at a volume ratio of 1:1, stirred for 10 minutes at a stirring speed of 200 rpm, and a 2% CaCl2 solution was added dropwise, the volume of the CaCl2 solution added being the same as that of the sodium alginate solution, and the solution was allowed to stand and solidify for 30 minutes, and filtered to obtain Chlorella microspheres;

[0046] S5: 1g of Bacillus subtilis inoculum (5×10 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.2g Nitrosomonas bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.0g Nitrobacter agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.8 g of glucose, 0.4 g of potassium fulvic acid, 0.7 g of potassium dihydrogen phosphate, 1.0 g of glycerol and 2.8 g of water were mixed and stirred to obtain a microbial composite agent;

[0047] S6: Mix 55g of modified biochar composite material with 13g of microbial composite agent, stir at 40rpm for 35min, add 2g of glutaraldehyde, 1g of chitosan, and 1g of gelatin, stir for 10min, add 24g of Chlorella microspheres, stir for 12min to obtain mixture C, transfer mixture C to a granulator to make granules, control the particle size to 0.3-1mm, freeze-dry the granules to obtain an aquaculture water environment remediation agent.

[0048] Example 3:

[0049] An aquaculture water environment repair agent comprises the following preparation steps:

[0050] S1: 40 g of wheat straw and 20 g of attapulgite were mixed, passed through a 100-mesh sieve, and soaked in 3% dilute hydrochloric acid for 2 h at a solid-liquid mass ratio of 1:5. The mixture was filtered, washed with deionized water until neutral, and dried to obtain a mixture A.

[0051] S2: Add mixture A, 20 g FeSO4˙7H2O, and 4 g NiSO4˙6H2O to 100 g deionized water, mix well, and dry to obtain mixture B. Place mixture B in a programmed temperature tube furnace and heat to 450°C at a heating rate of 5°C / min under nitrogen protection. Keep warm for 120 min, wash, and dry to obtain a biochar composite material.

[0052] S3: adding the biochar composite material to a 6% tannic acid solution, stirring for 8 h, and filtering to obtain a modified biochar composite material;

[0053] S4: Under the conditions of light intensity of 3000 lx and temperature of 30 °C, the Chlorella vulgaris was cultured using BG-11 medium until the cell density reached 1.5 × 10 8 -3.0×10 8 cells / ml, to obtain a Chlorella algae solution, the Chlorella algae solution was mixed with a 3% sodium alginate solution at a volume ratio of 1:1, stirred for 15 minutes at a stirring speed of 500 rpm, and a 2% CaCl2 solution was added dropwise, the volume of the CaCl2 solution added being the same as that of the sodium alginate solution, and the solution was allowed to stand and solidify for 30 minutes, and filtered to obtain Chlorella microspheres;

[0054] S5: 1g of Bacillus subtilis inoculum (5×10 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.5g Nitrosomonas bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.5g Nitrobacter bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 2g glucose, 0.5g potassium fulvic acid, 0.8g potassium dihydrogen phosphate, 1.2g glycerol and 3.2g water were mixed and stirred to obtain a microbial composite agent;

[0055] S6: Mix 60 g of modified biochar composite material with 17 g of microbial composite agent, stir at 50 rpm for 40 min, add 2 g of glutaraldehyde, 1.5 g of chitosan, and 0.5 g of polyvinyl alcohol and stir for 15 min, add 25 g of Chlorella microspheres and stir for 15 min to obtain mixture C, transfer mixture C to a granulator to make granules, control the particle size to 0.3-1 mm, freeze-dry the granules to obtain an aquaculture water environment remediation agent.

[0056] Comparative Example 1:

[0057] Compared with Example 1, the biochar composite material in this comparative example was not modified with tannic acid, and the remaining steps and parameters were the same, which will not be repeated in this comparative example. Finally, an aquaculture water environment repair agent was obtained.

[0058] Comparative Example 2:

[0059] Compared with Example 1, this comparative example only replaces the "4% tannic acid solution" with the "2% tannic acid solution", and the remaining steps and parameters are the same. This comparative example will not be repeated, and finally the aquaculture water environment repair agent is obtained.

[0060] Comparative Example 3:

[0061] Compared with Example 1, this comparative example only replaces the "4% tannic acid solution" with "8% tannic acid solution", and the remaining steps and parameters are the same. This comparative example will not be repeated, and finally an aquaculture water environment repair agent is obtained.

[0062] Comparative Example 4:

[0063] Compared with Example 1, this comparative example only replaces the "4% tannic acid solution" with the "10% tannic acid solution", and the remaining steps and parameters are the same. This comparative example will not be repeated, and finally the aquaculture water environment repair agent is obtained.

[0064] Comparative Example 5:

[0065] Compared with Example 1, this comparative example only replaces the "1% CaCl2 solution" with "0.5% CaCl2 solution", and the remaining steps and parameters are the same. This comparative example will not be repeated, and finally the aquaculture water environment repair agent is obtained.

[0066] Comparative Example 6:

[0067] Compared with Example 1, this comparative example only replaces the "1% CaCl2 solution" with "3% CaCl2 solution", and the remaining steps and parameters are the same. This comparative example will not be repeated, and finally an aquaculture water environment repair agent is obtained.

[0068] Comparative Example 7:

[0069] Compared with Example 1, this comparative example only replaces "attapulgite" with "zeolite", and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, an aquaculture water environment repair agent is obtained.

[0070] Performance testing:

[0071] It is used in a whiteleg shrimp farming pond. The pond covers an area of 17 mu and has a water depth of 1.6 meters. Due to the high stocking density and large amount of feed input, and the high temperature season (August), the water color becomes darker and appears yellow-brown. The water visibility is low, only 14 cm. In addition, the water emits a pungent odor. Water sampling is carried out in the whiteleg shrimp farming pond. The single sampling is 5m 3 The aquaculture water environment repair agent prepared in the above examples 1-3 and comparative examples 1-7 was used in the sampled water of the aquaculture pond at a dosage of 1 g / m 3 A water sample without the remediation agent was also set up as a control group. Ammonia nitrogen, nitrite, heavy metal (Pb, Cd, Hg) levels, as well as visibility, BOD, and COD, were tested on days 1, 3, and 7. The average particle size (D50) of the remediation agent particles and the state of the remediation agent (suspended / sunk) were also recorded. Detailed results are shown in Table 1 (Day 1 results), Table 2 (Day 2 results), and Table 3 (Day 3 results).

[0072] Table 1

[0073]

[0074] Table 2

[0075]

[0076] Table 3

[0077]

[0078]

[0079] Data Analysis:

[0080] It can be seen from Tables 1, 2 and 3 that the aquaculture water environment remediation agent prepared by the present invention has high pollutant removal efficiency and is easy to recycle, providing an efficient and environmentally friendly solution for aquaculture water remediation.

[0081] Comparative Examples 1-4 prove that a tannic acid solution concentration of 4%-6% is the best choice. This concentration range can not only significantly improve the removal efficiency of pollutants, but also ensure the stability and recyclability of the repair agent particles. Too high or too low a tannic acid concentration will lead to a decrease in the performance of the repair agent. If the molecular weight of tannic acid on the surface of the modified biochar composite material is too much, although it can improve the removal efficiency of pollutants in the early stage, it will also cause the bridging effect of tannic acid molecules to be too strong, the particle size of the agglomerates to increase too quickly, the repair agent particles are easy to sink to the bottom, shortening the contact time with pollutants and weakening the overall purification effect. If the tannic acid concentration is too low, the number of active groups is limited, and heavy metals cannot be fully complexed, resulting in a significant decrease in adsorption capacity, weakening the bridging effect of tannic acid molecules, insufficient binding force between repair agent particles, and flocs that are easily dispersed by water flow, making recovery more difficult.

[0082] The microbial composite agent decomposes organic matter in water and reduces the content of ammonia nitrogen and nitrite through the combined action of Bacillus subtilis, Nitrosomonas and Nitrobacter. Chlorella absorbs carbon dioxide through photosynthesis, releases oxygen, increases dissolved oxygen in water, improves water quality, and provides oxygen for aerobic bacteria, playing a synergistic role. Comparative Examples 5-6 prove that the concentration of CaCl2 solution of 1%-2% is the best choice. Excess Ca 2+ When cross-linked with sodium alginate, a highly dense gel network is formed, which results in limited light penetration. The dense structure hinders light from entering the microspheres, inhibits the photosynthesis of Chlorella, reduces oxygen release, and lowers the dissolved oxygen level. In addition, Ca 2+ Compete with heavy metal ions for adsorption sites, reducing the adsorption efficiency of the remediation agent for target pollutants, Ca 2+ When Ca is insufficient, 2+ The gel network formed with sodium alginate is sparse, which affects the fixation of microorganisms and algae, thereby affecting the removal of pollutants.

[0083] In Comparative Example 7, since "attapulgite" is replaced with "zeolite", the pollutant removal efficiency and pollutant removal ability of the finally prepared aquaculture water environment remediation agent are reduced. The porous structure of attapulgite and the abundant functional groups such as hydroxyl and carboxyl groups on its surface are conducive to the adsorption of microorganisms and pollutants, which helps to fix microorganisms and pollutants. In addition, attapulgite can form a colloidal suspension system in water. Its own viscosity not only increases its own viscosity, but also synergizes with tannic acid to form a floc structure, further promoting the coagulation and precipitation of pollutants, enhancing the adsorption efficiency, and can also synergize with tannic acid to form a floc structure, further promoting the coagulation and precipitation of pollutants, effectively removing suspended particles in water, and improving the transparency of water bodies.

[0084] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0085] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A breeding water environment repair agent, characterized in that: The aquaculture water environment restoration agent is prepared from the following components in parts by weight: 50-60 parts of modified biochar composite material, 22-25 parts of chlorella microspheres, 3-5 parts of a cross-linking agent, and 10-17 parts of a microbial composite agent.

2. The aquaculture water environment repair agent according to claim 1, characterized in that Preparation method of the biochar composite material: A1: mixing attapulgite and biomass raw materials, crushing, sieving, acid-activating, filtering, and drying to obtain a mixture A; A2: Add mixture A, FeSO4˙7H2O, and NiSO4˙6H2O to deionized water, mix well, and dry to obtain mixture B. Place mixture B in a programmed temperature tube furnace and heat to 450°C at a heating rate of 3-5°C / min under nitrogen protection. Keep warm for 100-120 min, wash, and dry to obtain a biochar composite material. A3: Add the biochar composite material to the tannic acid solution, stir for 6-8 hours, and filter to obtain the modified biochar composite material.

3. The aquaculture water environment repair agent according to claim 2, characterized in that: The biomass raw material is any one of peanut shells, rice husks and wheat straw.

4. The aquaculture water environment repair agent according to claim 2, characterized in that: The mass ratio of the biomass raw material, attapulgite, FeSO4˙7H2O, NiSO4˙6H2O and deionized water is 20:5-10:9-10:1-2:

100.

5. The aquaculture water environment repair agent according to claim 1, characterized in that The preparation method of the chlorella microspheres is as follows: culturing the chlorella to a cell density of 1.5×10 8 cells˙ml -1 -3.0×10 8 cells˙ml -1 Then, mix it evenly with sodium alginate solution and add CaCl2 solution dropwise to obtain Chlorella microspheres.

6. The aquaculture water environment restoration agent according to claim 1, characterized in that: The microbial composite agent comprises, by weight, a Bacillus subtilis agent, a Nitrosomonas agent, a Nitrobacter agent, glucose, potassium fulvic acid, potassium dihydrogen phosphate, glycerol and water in a mass ratio of 1:1-1.5:1-1.5:1.5-2:0.3-0.5:0.5-0.8:0.8-1:2.3-3.

2.

7. The aquaculture water environment restoration agent according to claim 6, characterized in that: The bacterial content of the Nitrosomonas bacteria agent and the Nitrobacter bacteria agent is 1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 The bacterial content of Bacillus subtilis inoculum is 5×10 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 .

8. The aquaculture water environment restoration agent according to claim 1, characterized in that: The cross-linking agent is any one or more of glutaraldehyde, chitosan, gelatin and polyvinyl alcohol.

9. The method for preparing the aquaculture water environment restoration agent according to any one of claims 1 to 8, characterized in that: The method comprises the following preparation steps: Step S1: mixing the biochar composite material and the microbial composite agent, adding a cross-linking agent, stirring for 30-40 minutes, adding Chlorella microspheres, and stirring for 10-15 minutes to obtain a mixture C; Step S2: extruding the mixture C into granules and freeze-drying it to obtain an aquaculture water environment repair agent.

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