Aquaculture water environment remediation agent and preparation method thereof

Abstract

This invention relates to the field of aquaculture technology, specifically to a remediation agent for aquaculture water environments and its preparation method. The remediation agent comprises a modified biochar composite material, Chlorella microspheres, a cross-linking agent, and a microbial composite inoculant. The modified biochar composite material is prepared through steps such as mixing attapulgite with biomass raw materials, acid activation, and pyrolysis, and further modified with tannic acid to enhance its adsorption capacity. The Chlorella microspheres are prepared using sodium alginate and CaCl2 solution, exhibiting good suspension and stability. The microbial composite inoculant contains various beneficial bacteria that can decompose organic matter and reduce ammonia nitrogen and nitrite content. The remediation agent binds the components together using a cross-linking agent to form granules, facilitating application and recovery. This remediation agent possesses highly efficient pollutant removal capabilities, significantly improving water quality in aquaculture water bodies, increasing water transparency, increasing dissolved oxygen, and promoting the health and stability of aquatic ecosystems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aquaculture, and particularly relates to a breeding water environment remediation agent and a preparation method thereof. BACKGROUND

[0002] In the field of aquaculture, due to high stocking density of aquatic animals and large amount of feed, a large amount of nitrogen-containing organic matters such as residual feed, excreta of animals and plants, and dead bodies are accumulated in the breeding water. At the same time, untreated breeding wastewater and industrial and domestic wastewater are discharged or washed by rainwater into the breeding water, so that the pollutants such as ammonia nitrogen, nitrite and heavy metals in the breeding water exceed the standard, and there are also organic pollutants such as hormones, antibiotics and colored dyes. These pollutants have the characteristics of large discharge amount, long residence time in water, great harm and difficult degradation, are easy to enrich in the organism, can cause serious irreversible influence on human health and environment, and are difficult to remove by water self-purification, thus causing a series of problems, such as large growth of harmful bacteria and pathogenic bacteria caused by high concentration of ammonia nitrogen or nitrite, poor physical condition of breeding animals such as fish and shrimp, poor stress resistance, easy to be attacked by pathogenic bacteria, and thus causing large-scale outbreak of aquatic animal diseases. Therefore, it is urgent to find an efficient, environmentally friendly and low-cost water pollution remediation technology.

[0003] In view of the demand for adsorption and removal of pollutants, biochar (BC) is a carbon material made by pyrolysis of biomass, which has the characteristics of porosity, high specific surface area and stability, and shows unique advantages. However, ordinary powder biochar has the disadvantages of small particle size and light texture, is easy to diffuse with water to cause secondary pollution, and usually needs to be separated from the environment medium by centrifugation and filtration, which limits the application of BC in water pollution remediation technology.

[0004] As a water remediation technology based on ecological principles, the microbial method has the advantages of being natural, self-repairing, long-acting and safe, but the application range of microorganisms is limited, different microorganisms have degradation capacity for specific pollutants, and the treatment effect on heavy metals is limited. At the same time, the immobilization and free of microorganisms are also the key factors affecting the application effect. Although the immobilized microorganisms can improve the stability, facilitate recycling and reuse, the contact efficiency of the immobilized microorganisms is reduced due to the limitation of the carrier; and the free microorganisms are easy to be disturbed by the environment and difficult to be recycled.

[0005] Therefore, according to the limitations of the above-mentioned related technologies, it is urgent to develop a new type of breeding water environment remediation agent which can effectively combine the high adsorption performance of biochar and the degradation capacity of microorganisms, and overcome the respective defects of the two, so as to provide a feasible solution for the water pollution problem of aquaculture. SUMMARY

[0006] In view of this, the purpose of this invention is to provide 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] To achieve the above objectives, the present invention provides an aquatic environment remediation agent and its preparation method.

[0008] An aquaculture water environment remediation agent includes the following preparation steps:

[0009] S1: Mix biomass raw materials with attapulgite in a certain 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 mixture A;

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

[0011] S3: Add the biochar composite material to the tannic acid solution, stir for 6-8 hours, and filter to obtain the modified biochar composite material;

[0012] S4: Chlorella was cultured in BG-11 medium under conditions of 2000-3000 lx light intensity and 25-30℃ until its cell density reached 1.5 × 10⁻⁶ cells / year. 8 -3.0×10 8 cells / ml. Chlorella algae solution was obtained. The Chlorella algae solution and sodium alginate solution were mixed in a 1:1 volume ratio and stirred for 10-15 minutes at a stirring speed of 200-500 rpm. CaCl2 solution was added dropwise, with the volume of CaCl2 solution added being the same as that of the sodium alginate solution. The mixture was allowed to stand and solidify for 20-30 minutes, then filtered to obtain Chlorella microspheres.

[0013] S5: Mix Bacillus subtilis inoculant, Nitrosomonas inoculant, Nitrobacterium nitrification inoculant, glucose, potassium humate, potassium dihydrogen phosphate, glycerol and water in a certain proportion and stir evenly to obtain a microbial compound inoculant;

[0014] S6: Mix the modified biochar composite material with the microbial composite agent and stir at 30-50 rpm for 30-40 min. Add the crosslinking agent and stir for 10-15 min. Add Chlorella microspheres and stir for 10-15 min to obtain mixture C. Transfer mixture C to a granulator to make granules, controlling the particle size to 0.3-1 mm. Freeze-dry the granulated particles to obtain the aquaculture water environment restoration 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 compound inoculant comprises Bacillus subtilis inoculant, Nitrosomonas inoculant, Nitrifying bacteria inoculant, glucose, potassium humate, 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.

[0018] The Bacillus subtilis decomposes organic matter in water by secreting extracellular enzymes, converting it into small molecules to provide nutrients for other microorganisms. Nitrifying bacteria oxidize ammonia nitrogen to nitrite, and nitrifying bacteria further oxidize nitrite to 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, Nitrifying bacteria, and nitrifying bacteria, promoting their metabolic activities, forming a synergistic effect, and jointly maintaining the ecological balance of the water body.

[0019] Preferably, the bacterial count of both the Nitrosomonas inoculant and the Nitrobacterium inoculant is 1×10⁻⁶. 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 The bacterial count of Bacillus subtilis inoculant is 5 × 10⁻⁶. 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 .

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

[0021] Preferably, the tannic acid solution has a mass fraction of 4%-6%. Tannic acid is a polyphenolic compound with a complex structure, containing a large number of hydroxyl and phenolic hydroxyl groups, which can react with heavy metals such as Pb through complexation. 2+ Cd 2+ The rapid binding and formation of stable complexes significantly improves adsorption efficiency in a short period. This complexation effectively fixes heavy metal ions from the water, thus achieving their removal. Furthermore, because tannic acid molecules are rich in hydroxyl and phenolic hydroxyl groups, they can bridge the aquatic environment remediation agent particles together, forming flocs. The hydrophobic portion of tannic acid promotes floc formation and stability, making the particles within the flocs more tightly bound together, less susceptible to being dispersed by water flow, and facilitating the recovery and reuse of the aquatic environment remediation agent.

[0022] Preferably, the sodium alginate solution has a mass fraction of 3%. Sodium alginate is a natural polysaccharide with good gelling properties, stability, and biocompatibility. It plays a protective role for microbial cells and forms a stable gel structure when it cross-links with calcium ions, which encapsulates Chlorella cells and fixes the cells.

[0023] Preferably, the mass fraction of the CaCl2 solution is 1%-2%, with excess Ca... 2+ Cross-linking with sodium alginate to form a dense gel network restricts light penetration, inhibits photosynthesis and oxygen release in Chlorella, reduces dissolved oxygen levels, and simultaneously... 2+ Competition for adsorption sites with heavy metal ions weakens the adsorption efficiency of remediation agents for pollutants; while Ca 2+ When the gel network is insufficient, it becomes sparse, affecting the fixation of microorganisms and Chlorella, thereby reducing the efficiency of pollutant removal.

[0024] The beneficial effects of this invention are:

[0025] 1. The aquaculture water environment remediation agent prepared by this invention has a highly efficient pollutant removal capacity. Through the synergistic effect of modified biochar composite material, Chlorella microspheres, and microbial compound inoculants, 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 material, combined with the complexation effect of tannic acid, enhance the adsorption capacity for pollutants; the various inoculants in the microbial compound inoculant can decompose organic matter and reduce the content of ammonia nitrogen and nitrite; Chlorella absorbs carbon dioxide and releases oxygen through photosynthesis, further improving water quality.

[0026] 2. The remediation agent prepared by this invention forms a colloidal suspension system in water with viscosity, which can synergistically interact with tannic acid to form a stable floc structure. This floc structure not only enhances the binding force between the remediation agent particles, making them more tightly bound together and less easily dispersed by water flow, but also facilitates the recovery and reuse of the remediation agent.

[0027] 3. The biomass raw materials used in this invention are all agricultural waste, which are widely available and inexpensive, realizing the resource utilization of waste and possessing good economic and sustainable characteristics. The remediation 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 arise from traditional remediation agents, thus being environmentally friendly. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] The Bacillus subtilis in the examples was obtained from the China Center for Type Culture Collection, with accession number CCTCCNo:M2011443.

[0030] The Nitrosomonas bacteria in the examples were obtained from the China General Microbiological Culture Collection Center, with accession number CGMCC 11865.

[0031] The nitrifying bacteria in the examples were obtained from the China Center for Type Culture Collection, with accession number CCTCC NO:M2014203.

[0032] Example 1:

[0033] An aquaculture water environment remediation agent includes the following preparation steps:

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

[0035] S2: Add mixture A, 18g FeSO4˙7H2O, and 2g NiSO4˙6H2O to 100g deionized water, mix evenly, and dry to obtain mixture B. Place mixture B in a programmed temperature rise tube furnace, heat to 450℃ at a heating rate of 3℃ / min under nitrogen protection, hold for 100min, wash and dry to obtain biochar composite material;

[0036] S3: Add the biochar composite material to a 4% tannic acid solution, stir for 6 hours, and filter to obtain the modified biochar composite material.

[0037] S4: Chlorella was cultured in BG-11 medium at a light intensity of 2000 lx and a temperature of 25°C until its cell density reached 1.5 × 10⁻⁶ cells / year. 8 -3.0×10 8 The Chlorella algae solution was obtained by measuring cells / ml. The Chlorella algae solution was mixed with 4% sodium alginate solution at a volume ratio of 1:1 and stirred for 10 min at a stirring speed of 500 rpm. 1% CaCl2 solution was added dropwise, with the volume of CaCl2 solution added being the same as that of sodium alginate solution. The mixture was allowed to stand and solidify for 20 min, then filtered to obtain Chlorella microspheres.

[0038] S5: Add 1g of Bacillus subtilis inoculum (5×10) 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1g Nitrosomonas inoculum (1×10) 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1g of nitrifying bacteria agent (1×10) 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 Mix 1.5g glucose, 0.3g potassium humate, 0.5g potassium dihydrogen phosphate, 0.8g glycerol and 2.3g water, and stir well to obtain a microbial compound inoculant;

[0039] S6: Mix 50g of modified biochar composite material with 10g of microbial composite inoculant, 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 granulated particles to obtain the aquatic environment restoration agent.

[0040] Example 2:

[0041] An aquaculture water environment remediation agent includes the following preparation steps:

[0042] S1: Mix 40g of rice husks with 15g of attapulgite, pass through a 100-mesh sieve, soak in 3% dilute hydrochloric acid for 2.5h, with a solid-liquid mass ratio of 1:5, filter, wash with deionized water until neutral, and dry to obtain mixture A;

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

[0044] S3: Add the biochar composite material to a 5% tannic acid solution, stir for 7 hours, and filter to obtain the modified biochar composite material.

[0045] S4: Chlorella was cultured in BG-11 medium at a light intensity of 2500 lx and a temperature of 25℃ until its cell density reached 1.5 × 10⁻⁶ cells / year. 8 -3.0×10 8 The Chlorella algae solution was obtained by measuring cells / ml. The Chlorella algae solution was mixed with 3% sodium alginate solution at a volume ratio of 1:1 and stirred for 10 min at a stirring speed of 200 rpm. 2% CaCl2 solution was added dropwise, with the volume of CaCl2 solution added being the same as that of sodium alginate solution. The mixture was allowed to stand and solidify for 30 min, then filtered to obtain Chlorella microspheres.

[0046] S5: Add 1g of Bacillus subtilis inoculum (5×10) 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.2g Nitrosomonas inoculum (1×10) 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.0g of nitrifying bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 Mix 1.8g glucose, 0.4g potassium humate, 0.7g potassium dihydrogen phosphate, 1.0g glycerol and 2.8g water, and stir well to obtain a microbial compound inoculant.

[0047] S6: Mix 55g of modified biochar composite material with 13g of microbial composite inoculant, stir at 40rpm for 35min, add 2g of glutaraldehyde, 1g of chitosan and 1g of gelatin and stir for 10min, add 24g of Chlorella microspheres and 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 granulated particles to obtain the aquatic environment restoration agent.

[0048] Example 3:

[0049] An aquaculture water environment remediation agent includes the following preparation steps:

[0050] S1: Mix 40g of wheat straw with 20g of attapulgite, pass through a 100-mesh sieve, soak in 3% dilute hydrochloric acid for 2 hours, with a solid-liquid mass ratio of 1:5, filter, wash with deionized water until neutral, and dry to obtain mixture A.

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

[0052] S3: Add the biochar composite material to a 6% tannic acid solution, stir for 8 hours, and filter to obtain the modified biochar composite material.

[0053] S4: Chlorella was cultured in BG-11 medium at a light intensity of 3000 lx and a temperature of 30℃ until its cell density reached 1.5 × 10⁻⁶ cells / year. 8 -3.0×10 8 The Chlorella algae solution was obtained by measuring cells / ml. The Chlorella algae solution was mixed with 3% sodium alginate solution at a volume ratio of 1:1 and stirred for 15 min at a stirring speed of 500 rpm. 2% CaCl2 solution was added dropwise, with the volume of CaCl2 solution added being the same as that of sodium alginate solution. The mixture was allowed to stand and solidify for 30 min, then filtered to obtain Chlorella microspheres.

[0054] S5: Add 1g of Bacillus subtilis inoculum (5×10) 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.5g Nitrosomonas inoculum (1×10) 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 ), 1.5g of nitrifying bacteria agent (1×10 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 Mix 2g glucose, 0.5g potassium humate, 0.8g potassium dihydrogen phosphate, 1.2g glycerol and 3.2g water, and stir well to obtain a microbial compound inoculant;

[0055] S6: Mix 60g of modified biochar composite material with 17g of microbial composite agent and stir at 50rpm for 40min. Add 2g of glutaraldehyde, 1.5g of chitosan and 0.5g of polyvinyl alcohol and stir for 15min. Add 25g of Chlorella microspheres and stir for 15min to obtain mixture C. Transfer mixture C to a granulator to make granules, control the particle size to 0.3-1mm, freeze-dry the granulated particles to obtain the aquatic environment restoration 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. Therefore, the details of this comparative example will not be repeated. The final product is an aquaculture water environment restoration agent.

[0058] Comparative Example 2:

[0059] Compared with Example 1, this comparative example only replaces "4% tannic acid solution" with "2% tannic acid solution". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0060] Comparative Example 3:

[0061] Compared with Example 1, this comparative example only replaces "4% tannic acid solution" with "8% tannic acid solution". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0062] Comparative Example 4:

[0063] Compared with Example 1, this comparative example only replaces "4% tannic acid solution" with "10% tannic acid solution". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0064] Comparative Example 5:

[0065] Compared with Example 1, this comparative example only replaces "1% CaCl2 solution" with "0.5% CaCl2 solution". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0066] Comparative Example 6:

[0067] Compared with Example 1, this comparative example only replaces "1% CaCl2 solution" with "3% CaCl2 solution". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0068] Comparative Example 7:

[0069] This comparative example differs from Example 1 only in that "attapulgite" is replaced with "zeolite". All other steps and parameters are the same, and will not be repeated here. The final aquaculture water environment restoration agent is obtained.

[0070] Performance testing:

[0071] This was conducted in a Litopenaeus vannamei shrimp farming pond. The pond covers an area of ​​17 mu (approximately 1.1 hectares) and has a water depth of 1.6 meters. Due to high stocking density, large feed input, and the presence of high temperatures (August), the water color has darkened to a yellowish-brown, with low visibility of only 14 cm. Furthermore, the water emits a pungent odor. Water samples were taken from the Litopenaeus vannamei shrimp farming pond, with each sample measuring 5 m. 3 The aquaculture water environment remediation agents prepared in Examples 1-3 and Comparative Examples 1-7 were used in water samples taken from the aquaculture pond at a dosage of 1 g / m³. 3 A water sample without added remediation agent was used as a control group. Ammonia nitrogen, nitrite, heavy metals (Pb, Cd, Hg), visibility, BOD, and COD were measured on days 1, 3, and 7, respectively. The average particle size (D50) and state (suspended / settled) of the remediation agent were also recorded. Detailed results are shown in Tables 1 (day 1), 2 (day 2), and 3 (day 3).

[0072] Table 1

[0073]

[0074] Table 2

[0075]

[0076] Table 3

[0077]

[0078]

[0079] Data Analysis:

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

[0081] Comparative examples 1-4 demonstrate that a tannic acid solution concentration of 4%-6% is optimal. This concentration range significantly improves pollutant removal efficiency while ensuring the stability and recyclability of the remediation agent particles. Excessively high or low tannic acid concentrations will lead to a decline in remediation agent performance. If the modified biochar composite material has an excessive amount of tannic acid molecules on its surface, although it may initially improve pollutant removal efficiency, it can also result in overly strong tannic acid molecular bridging, excessively rapid increase in aggregate particle size, easy settling of remediation agent particles, shortened contact time with pollutants, and weakened overall purification effect. If the tannic acid concentration is too low, the limited number of active groups cannot adequately complex heavy metals, leading to a significant reduction in adsorption capacity, weakened tannic acid molecular bridging, insufficient binding force between remediation agent particles, easy dispersal of flocs by water flow, and increased difficulty in recovery.

[0082] The microbial compound inoculant works synergistically with Bacillus subtilis, Nitrosomonas, and Nitrifying Bacillus to decompose organic matter in water, reducing ammonia nitrogen and nitrite levels. Chlorella absorbs carbon dioxide and releases oxygen through photosynthesis, increasing dissolved oxygen in the water, improving water quality, and providing oxygen for aerobic bacteria, thus playing a synergistic role. Comparative examples 5-6 demonstrate that a 1%-2% CaCl2 solution concentration is optimal. Excess Ca... 2+ When cross-linked with sodium alginate, it forms a highly dense gel network, which restricts light penetration. The dense structure hinders light from entering the microspheres, inhibits photosynthesis in Chlorella, reduces oxygen release, and lowers dissolved oxygen levels. Furthermore, Ca... 2+ Competing with heavy metal ions for adsorption sites reduces the adsorption efficiency of the remediation agent for the target pollutant. 2+ When insufficient, Ca 2+ The sparse gel network formed with sodium alginate affects the fixation of microorganisms and small algae, thus impacting the removal of pollutants.

[0083] In Comparative Example 7, replacing "attapulgite" with "zeolite" resulted in a decrease in the pollutant removal efficiency and decontamination capacity of the final aquaculture water environment remediation agent. The porous structure and abundant hydroxyl and carboxyl functional groups on the surface of attapulgite are beneficial for adsorbing microorganisms and pollutants, aiding in their fixation. Furthermore, attapulgite can form a colloidal suspension system in water. Its own viscosity not only enhances adsorption efficiency but also synergistically forms flocculent structures with tannins, further promoting the coagulation and precipitation of pollutants, effectively removing suspended particles from the water and improving water transparency.

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

[0085] This 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 this invention should be included within the scope of protection of this invention.

Claims

1. A water environment restoration agent for aquaculture, characterized in that, The aquaculture water environment restoration agent is made of 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 crosslinking agent, and 10-17 parts of microbial compound agent. The preparation method of the biochar composite material: A1: Mix attapulgite and biomass raw materials, crush, sieve, acid-activate, filter, and dry to obtain mixture A; A2: Add mixture A, FeSO4˙7H2O, and NiSO4˙6H2O to deionized water, mix evenly, and dry to obtain mixture B. Place mixture B in a programmed temperature rise tube furnace and heat to 450℃ at a heating rate of 3-5℃ / min under nitrogen protection. Hold at this temperature for 100-120min, wash, and dry to obtain the 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; 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; The method for preparing the Chlorella microspheres is as follows: Chlorella is cultured until the cell density reaches 1.5 × 10⁻⁶ cells / year. 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; The microbial compound inoculant consists of Bacillus subtilis inoculant, Nitrosomonas inoculant, Nitrifying Bacillus inoculant, glucose, potassium humate, 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.

2. The aquaculture water environment restoration agent according to claim 1, characterized in that: The biomass raw material is any one of peanut shells, rice husks, and wheat straw.

3. The aquaculture water environment restoration agent according to claim 1, characterized in that: The bacterial count of both the Nitrosomonas inoculant and the Nitrobacterium inoculant is 1×10⁻⁶. 9 CFU˙ml -1 -1×10 10 CFU˙ml -1 The bacterial count of Bacillus subtilis inoculant is 5 × 10⁻⁶. 8 CFU˙ml -1 -1×10 10 CFU˙ml -1 .

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

5. The method for preparing the aquaculture water environment restoration agent according to any one of claims 1-4, characterized in that, The preparation steps include the following: Step S1: Mix the biochar composite material with the microbial composite inoculant, add the cross-linking agent, stir for 30-40 min, add Chlorella microspheres, stir for 10-15 min, and obtain mixture C; Step S2: Extrude and granulate the mixture C, and freeze-dry it to obtain the aquatic environment restoration agent.

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