Bionic aquatic plant substrate with slow release and biological membrane culture functions

Abstract

The invention relates to the technical field of water body remediation, and particularly discloses a bionic aquatic plant matrix with slow release and biological membrane culture functions. A preparation method of the bionic aquatic plant matrix with the slow release and biological membrane culture functions comprises the following steps: preparing gradient porous biochar-based fibers, preparing functional fibers, weaving imitated aquatic plant clusters, and manufacturing the modularized bionic aquatic plant matrix. The specific surface area of the obtained gradient porous biochar-based fiber can reach 300-800 m < 2 > / g, and the specific surface area of a carrier is greatly increased. The biofilm formation biomass of the biomimetic aquatic plant matrix for repairing the water body is 20-60 mg / g, the biofilm formation starting time is 5-14 days, the ammonia nitrogen removal rate is 3-10 mg N / (g.d), the impact resistance recovery time is 12-36 h, the microbial immobilization efficiency and the pollutant removal effect are greatly improved, and the impact resistance of the system is improved.

Description

Technical Field

[0001] This application relates to the field of water remediation technology, and more specifically, it relates to a biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions. Background Technology

[0002] With the acceleration of urbanization, the self-purification capacity of landscape water bodies, aquaculture water bodies, and natural water bodies has declined, and pollutant emissions have surged. The inability to form a stable ecological chain to degrade pollutants has led to frequent occurrences of excessive accumulation of nitrogen and phosphorus, enrichment of organic pollutants, eutrophication, and blackening and odorization in water bodies, severely damaging the stability of aquatic ecosystems. Water remediation technology, as a core means of improving the aquatic environment, plays a crucial role in areas such as microbial enrichment and pollutant degradation.

[0003] Currently, water remediation technology provides a carrier that offers attachment sites for functional microorganisms such as nitrifying and denitrifying bacteria. A biofilm is then formed on the surface of the carrier to degrade organic pollutants, nitrogen, phosphorus, and other nutrients in the water. At the same time, the turbidity of the water is reduced through physical interception, thereby restoring the aquatic environment.

[0004] In related technologies, water bioremediation technology mainly uses natural aquatic plants, chemical fillers, or ordinary plastics as carriers for microbial attachment. However, natural aquatic plant carriers are prone to decay and are limited by the season, while chemical fillers or ordinary plastic carriers have a small specific surface area, slow microbial biofilm formation, and easy detachment. Furthermore, natural aquatic plants, chemical fillers, or ordinary plastics, as carriers for microbial attachment, have limited functions and lack continuous stimulation and protection for functional microorganisms, resulting in slow system start-up, unstable treatment efficiency, and susceptibility to water quality fluctuations. Summary of the Invention

[0005] In order to improve the specific surface area of ​​the carrier, the efficiency of microbial immobilization, the long-term activation of the metabolic activity of functional microorganisms, the system's shock resistance, and the flexibility and management efficiency of water body restoration, this application provides a biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions.

[0006] In a first aspect, this application provides a biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions, which adopts the following technical solution: A biomimetic aquatic plant substrate with slow-release and biofilm culture functions is prepared through the following steps: The biomimetic aquatic plant substrate is prepared through the following steps: Preparation of gradient porous biochar-based fibers: Agricultural waste is pyrolyzed and activated to produce gradient porous biochar. The gradient porous biochar is then blended with a polymer and spun to obtain gradient porous biochar-based fibers. Preparation of functionalized fibers: Gradient porous biochar-based fibers were immersed in MES buffer containing crosslinking agent and catalyst at pH 5.5 and activated by shaking at 25℃ for 30 min. The gradient porous biochar-based fibers were then removed and transferred to a mixed aqueous solution containing polyglutamic acid and microbial promoter. The reaction was carried out at 25-30℃ and pH 6.0-7.0 for 4-6 h. The fibers were washed with deionized water and stored at 4℃ to obtain functionalized fibers. Woven aquatic plant clusters: Functional fibers are woven into aquatic plant clusters with a three-dimensional branching structure and a height of 10-200cm. Constructing a modular biomimetic aquatic plant substrate: Multiple biomimetic aquatic plant clusters are fixed to a floating frame equipped with an anchoring system to obtain a modular biomimetic aquatic plant substrate.

[0007] In this application, agricultural waste is selected from any one or more of the following: corn stalks, wheat stalks, rice stalks, peanut shells, walnut shells, coconut shells, apricot shells, sugarcane bagasse, grape pomace, apple pomace, sawdust, bamboo shavings, and cotton stalks. The resulting biomimetic aquatic plant substrates all have high specific surface area, high microbial immobilization efficiency, and long-lasting activation function of microbial metabolic activity, which can improve the system's impact resistance, water body restoration flexibility, and management efficiency.

[0008] In the mixed aqueous solution containing polyglutamic acid and microbial promoter of this application, the mass percentage of polyglutamic acid is 2% and the mass percentage of microbial promoter is 1%.

[0009] In this application, the MES buffer containing crosslinking agent and catalyst has a MES buffer concentration of 0.1 mol / L, a crosslinking agent concentration of 50 mmol / L, and a catalyst concentration of 25 mmol / L.

[0010] Furthermore, the height of the aquatic plant clusters in this application is controlled at 30-100cm, which covers the typical needs from shallow wetlands to conventional waterways.

[0011] Furthermore, the floating frame of this application can be any one of square, rectangular, circular or hexagonal shapes, and the material can be any one or more of PVC, HDPE and PP; the side length or diameter of the floating frame is controlled between 0.3m and 3.0m, 0.3m is suitable for small test units or dense deployment, and 3.0m is suitable for large engineering modules, which facilitates mechanized hoisting and continuous deployment. The floating frame with a side length of 0.3m to 3.0m covers all scales from laboratory pilot tests to large-scale engineering applications.

[0012] By adopting the above technical solution, when preparing gradient porous biochar-based fibers, agricultural waste is first pyrolyzed to form crude biochar with a preliminary porous structure. After pyrolysis, the biochar has stable chemical properties and no longer has the hydrophilicity and easy degradation of natural straw. After being blended and spun with polymer, it can ensure that the prepared fibers are not easily decomposed in the aquatic environment and extend the service life of the biomimetic aquatic plant substrate.

[0013] Then, the crude biochar is activated to form a gradient-distributed porous structure on the biochar carbon skeleton, which greatly increases the specific surface area of ​​the biomimetic aquatic plant matrix as a carrier, provides adsorption sites for microbial promoters, improves the microbial immobilization efficiency, realizes the loading and slow release of microbial promoters, and accelerates the mass transfer efficiency between pollutants and microorganisms in the water.

[0014] Pure gradient porous biochar is in powder or granular form and has no filamentation ability, so it cannot be directly processed into the fiber form required for biomimetic aquatic plants. By blending gradient porous biochar with polymers and spinning, the biochar particles are uniformly dispersed in the polymer matrix. With the help of wet spinning process, continuous fiber filaments can be extruded, creating a preferred ecological niche from macro to micro, which is conducive to the whole process of microorganisms from adsorption and colonization to the formation of stable biofilm.

[0015] Gradient porous biochar-based fibers were immersed in a MES buffer containing a crosslinking agent (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) and a catalyst (N-hydroxysuccinimide). The fibers were then activated by shaking at 25°C for 30 minutes. The MES buffer activated the surface of the gradient porous biochar-based fibers. The covalently bonded polyglutamic acid hydrogel layer was not only strong, but also responded to environmental changes through the swelling and contraction of its network structure, enabling the slow and controlled release of internally embedded growth promoter molecules. This formed and maintained a highly active functional microbial dominant zone around the pollutants. Subsequently, the fibers were transferred to a mixed aqueous solution containing polyglutamic acid and microbial promoters to allow the microbial promoters to be fully adsorbed into the gradient pores of the fibers. Finally, the unadsorbed free microbial promoters on the surface were washed away, resulting in a functional fiber with multiple functions, including efficient biofilm cultivation, pollutant degradation, and long-term slow-release of microbial promoters. It can also effectively activate the metabolic activity of functional microorganisms and improve the system's shock resistance.

[0016] Functional fibers are woven into aquatic plant-like clusters, with a height controlled between 10-200cm. These clusters need a certain vertical length to create an effective three-dimensional purification space in the water. 10cm is a reasonable minimum size, differentiating it from traditional sheet-like or spherical fillers. Considering the actual water depth of most inland rivers, lakes, and landscape water bodies, as well as the stability and ease of installation of the modular floating frame, 200cm is sufficient for most application scenarios. For deeper water bodies, the suspension depth can be adjusted.

[0017] Then, multiple clusters of artificial aquatic plants are fixed to a floating frame equipped with an anchoring system. The whole structure forms a modular design of a "mobile biofilm reaction bed" that can be quickly deployed and retrieved. This modular design gives the equipment engineering advantages such as rapid deployment, easy monitoring and maintenance, and reusability, which greatly improves the flexibility and management efficiency of water body restoration.

[0018] Preferably, the pyrolysis specifically involves placing agricultural waste at 400-700℃ for 1-3 hours under inert gas protection, with a heating rate of 5-20℃ / min; the activation specifically involves placing the pyrolyzed agricultural waste at 600-900℃ and activating it under steam for 1-2 hours, followed by washing and drying.

[0019] Furthermore, the pyrolysis temperature of this application is 500-600℃.

[0020] By adopting the above scheme, agricultural waste is pyrolyzed at 400-700℃ for 1-3 hours under inert gas protection, resulting in a high biochar yield. Activation at 600-900℃ above the pyrolysis temperature allows for deep etching of the carbon skeleton formed by pyrolysis, producing gradient porous biochar with higher specific surface area and microbial immobilization efficiency. Macropores rapidly adsorb pollutants, while micropores provide a stable habitat for microorganisms.

[0021] Preferably, the pore size gradient of the gradient porous biochar is controlled to be 50nm-10μm, 2-50nm, or <2nm.

[0022] By adopting the above scheme, 50nm-10μm pores are used as transport pores, mainly located on the fiber surface or main channels. These pores serve as the main transport pathways for water, pollutants, and dissolved oxygen, rapidly transporting nitrogen, phosphorus, and recalcitrant organic matter from the water into the fiber interior, ensuring efficient adsorption of pollutants. 2-50nm pores act as transition pores, connecting the transport pores and protective pores to form a branched pore network, serving as the main loading sites for microbial promoters. <2nm pores act as protective pores, serving as the core colonization sites for microorganisms, preventing them from being affected by external interference such as water flow impact and competition from other bacteria, ensuring the stability of the biofilm, forming an anaerobic zone, meeting the anaerobic metabolic needs of denitrifying bacteria and polyphosphate-accumulating bacteria, and enhancing nitrogen and phosphorus removal efficiency.

[0023] Preferably, when the gradient porous biochar and polymer are blended and spun, the mass ratio of the gradient porous biochar to the polymer is controlled at 1:(4-9).

[0024] By adopting the above technical solution, the mass ratio of gradient porous biochar to polymer is controlled at 1:(4-9). The polymer can fully encapsulate the gradient porous biochar particles to form a continuous matrix network, ensuring that the gradient porous biochar-based fibers have sufficient tensile strength and flexibility after spinning, stretching, and shaping. This prevents breakage or disintegration in water due to water flow impact and wave disturbance. If the proportion of gradient porous biochar is too high, it will destroy the continuity of the polymer matrix, leading to increased fiber brittleness and easy breakage during spinning, making it impossible to form a continuous aquatic plant cluster. If the proportion of gradient porous biochar is too low, it will not provide sufficient microbial attachment sites and microbial promoter loading space.

[0025] Preferably, the polymer is selected from one or more of polycaprolactone, polyvinyl alcohol, and polylactic acid.

[0026] In this application, the polymer is selected from any one or more of polycaprolactone, polyvinyl alcohol, and polylactic acid. The resulting biomimetic aquatic plant matrix has a high specific surface area, high microbial immobilization efficiency, and long-lasting activation function of microbial metabolic activity, which can improve the system's shock resistance, water body restoration flexibility, and management efficiency.

[0027] Preferably, the gradient porous biochar and polymer blend spinning includes the following steps: S1. Dissolve the polymer in an organic solvent and stir until completely dissolved. Add dried gradient porous biochar, disperse evenly, and degas to obtain the spinning solution. S2. Inject the spinning solution at a temperature of 25-35℃ into the spinning pump, extrude it through a spinneret with an orifice diameter of 0.3-0.5mm, and enter the coagulation bath for 2-5 minutes at a temperature of 20-30℃ to form nascent fibers. S3. The nascent fibers are stretched 1.5-3 times at a stretching speed of 5-10 m / min, then dried and shaped at 40-60℃, and wound up to obtain gradient porous biochar-based fibers.

[0028] By adopting the above technical solution and adding dried gradient porous biochar, the moisture in the gradient porous biochar can be avoided from causing bubbles and phase separation in the spinning solution, ensuring that the gradient porous biochar is evenly dispersed in the polymer matrix and preventing agglomeration. Degassing can further prevent the formation of voids inside the fiber during extrusion, ensuring that the gradient porous structure is not damaged.

[0029] The spinning solution temperature is controlled at 25-35℃ to maintain a stable viscosity. Too low a temperature can lead to increased viscosity and poor spinneret flow, while too high a temperature may cause premature evaporation of organic solvents, resulting in spinneret blockage. The coagulation bath temperature is controlled at 20-30℃ to allow the nascent fibers to solidify rapidly, preventing the collapse of the gradient porous structure within the nascent fibers and achieving the transformation from liquid spinning solution to solid nascent fibers. After fiber formation, the gradient porous structure of biochar is retained.

[0030] The nascent fibers are stretched 1.5-2 times at a speed of 5-10 m / min to ensure the tensile strength and flexibility of the gradient porous biochar-based fibers. Then, they are dried to remove the residual organic solvent inside the gradient porous biochar-based fibers, which facilitates the efficient preparation of functional fibers in the subsequent process.

[0031] Preferably, the gradient porous biochar-based fiber has a diameter of 0.1-2.0 mm.

[0032] By adopting the above technical solution, it is found that gradient porous biochar-based fibers with a diameter <0.1mm are difficult to stably form in wet spinning processes, have too low mechanical strength, are easy to break, and are not suitable as underwater engineering materials that need to be used for long-term service. Fibers with a diameter >2.0mm will have a significantly reduced specific surface area, which is not conducive to the efficient attachment of microorganisms. By controlling the diameter to 0.1-2.0mm, it is possible to have a certain mechanical strength and not be easy to break. A diameter within 2.0mm can better balance strength and specific surface area.

[0033] Furthermore, the gradient porous biochar-based fiber of this application has a diameter of 0.3-1.0 mm, which can optimally ensure the synergy of high strength and high specific surface area.

[0034] Preferably, the microbial promoter is selected from one or more of the following: denitrification promoter, polyphosphate promoter, microbial quorum sensing signal molecule, trace element complex, rhamnolipid, and anthraquinone-2-sulfonate.

[0035] The denitrification promoter can be any one of 2-hydroxypyridine, sodium acetate, methanol, or citrate; the polyphosphate-accumulating bacteria promoter can be any one of sodium acetate or sodium propionate; the microbial quorum sensing signal molecule can be any one of acyl homoserine lactone, self-inducing peptide, or furan borate diester; and the trace element complex can be a chelate of Fe, Mo, or Co.

[0036] By adopting the above technical solutions, denitrification promoters serve as carbon sources, polyphosphate-accumulating bacteria promoters are used to enhance biological phosphorus removal, microbial quorum sensing signal molecules are used to promote biofilm formation, and trace element complexes are used to activate specific enzyme activities.

[0037] As a preferred option, when preparing functionalized fibers, the gradient porous biochar-based fibers are pretreated, specifically by immersing the gradient porous biochar-based fibers in 75% ethanol for disinfection and wetting, and then washing them with deionized water.

[0038] By adopting the above technical solution, the gradient porous biochar-based fiber is disinfected and moistened by immersing it in 75% ethanol, and then washed with deionized water to eliminate interference from miscellaneous bacteria. It can also quickly moisten the fiber surface and the inner wall of the pores, open up the transport channels, and ensure that the reagents for subsequent activation and grafting penetrate evenly into the gradient pores of the fiber. This provides sufficient binding sites for the grafting reaction, thereby ensuring the covalently bonded polyglutamic acid hydrogel layer is firm. The gradient porous biochar-based fiber continuously supplies microbial growth promoters, effectively activates the metabolic activity of functional microorganisms, and improves the system's shock resistance.

[0039] Secondly, this application provides an application of any of the above-mentioned biomimetic aquatic plant substrates with slow-release and biofilm cultivation functions, specifically achieved through the following technical solution: In summary, this application includes at least one of the following beneficial technical effects: (1) This application prepares gradient porous biochar-based fibers, so that the specific surface area of ​​the gradient porous biochar-based fibers can reach 300-800 m². 2 / g significantly increased the specific surface area of ​​the carrier, the biomass of biofilm formation in the biomimetic aquatic plant substrate for water body restoration was 35-40mg / g, the ammonia nitrogen removal rate was 6-7mg N / (g·d), the biofilm initiation time was 8-9 days, and the shock recovery time was 20-25h, which improved the efficiency of microbial immobilization and pollutant removal, and enhanced the system's shock resistance.

[0040] (2) By controlling the diameter of gradient porous biochar-based fibers, this application achieves a biomass of 50 mg / g of biofilm in water body restoration by biomimetic aquatic plant matrix, an ammonia nitrogen removal rate of 9 mg N / (g·d), a biofilm initiation time of 6 days, and a shock recovery time of 14 h, which further improves the microbial immobilization efficiency and pollutant removal effect, and enhances the system's shock resistance.

[0041] (3) This application pre-treats the gradient porous biochar-based fiber to make the biomass of biomimetic aquatic plant substrate in water body restoration 60mg / g, the ammonia nitrogen removal rate 10mg N / (g·d), the biomass start-up time 5 days, and the shock recovery time 12h, which further improves the microbial immobilization efficiency and pollutant removal effect, and enhances the system's shock resistance. Attached Figure Description

[0042] Figure 1 Imitation aquatic plant cluster pattern Figure 2 Biomimetic aquatic plant substrate diagram Detailed Implementation

[0043] The present application will be further described in detail below with reference to specific embodiments and accompanying drawings. All the raw materials used in this application are commercially available products and are intended to fully disclose the raw materials used in this application; they should not be construed as limiting the source of the raw materials. Specifically: agricultural waste, rice husks are selected; polymer, polycaprolactone, manufacturer Perstorp (Ingevity), model Capa 6800 is selected; crosslinking agent, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, with an effective substance content of 99% is selected; catalyst, N-hydroxysuccinimide, with an effective substance content of 99% is selected; MES buffer solution, concentration of 0.1 mol / L; polyglutamic acid, with an effective substance content of 25%; microbial promoter, 2-hydroxypyridine, a denitrification promoter, with an effective substance content of 99% is selected; organic solvent, dichloromethane, with an effective substance content of 99.9% is selected.

[0044] Example 1 The biomimetic aquatic plant substrate of Example 1 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: Under nitrogen protection, rice husks were kept at 550℃ for 2 hours with a heating rate of 10℃ / min. Pyrolyzed agricultural waste was then placed at 550℃ and activated with steam for 2 hours. After washing with deionized water, the fibers were dried at 80℃ for 2 hours to produce gradient porous biochar with 500nm and 1nm structures. The gradient porous biochar was then blended with a polymer and spun into fibers. Specifically, the polymer (polycaprolactone) was dissolved in an organic solvent (dichloromethane) at a mass-volume ratio of 10%. Stir until completely dissolved, add gradient porous biochar to polymer at a mass ratio of 1:3, disperse evenly, let stand to degas, and obtain spinning solution. Inject the spinning solution at 25℃ into spinning pump, extrude through a spinneret with a pore size of 0.4mm, enter a coagulation bath for 4min at a coagulation bath temperature of 25℃ to form nascent fibers, and then stretch the nascent fibers twice at a stretching speed of 8m / min. Subsequently, dry and shape at 50℃, and wind up to obtain gradient porous biochar-based fibers with a diameter of 0.1mm. Preparation of functionalized fibers: Gradient porous biochar-based fibers were immersed in MES buffer solution containing crosslinking agent (50 mmol / L) and catalyst (25 mmol / L) at pH 5.5 and activated by shaking at 25°C for 30 min. The gradient porous biochar-based fibers were then removed and transferred to a mixed aqueous solution containing 2% polyglutamic acid and 1% microbial promoter (hydroxypyridine). The reaction was carried out at 25°C and pH 6 for 5 h. The fibers were washed with deionized water and stored at 4°C to obtain functionalized fibers. Woven aquatic plant clusters: Functional fibers are woven into clusters with a three-dimensional branching structure, 50cm long, such as... Figure 1The simulated aquatic plant cluster is shown. Constructing a biomimetic aquatic plant substrate: Nine biomimetic aquatic plant clumps are fixed to a 1m square PVC floating frame equipped with an anchoring system, resulting in a biomimetic aquatic plant substrate, such as... Figure 2 As shown.

[0045] Example 2 The biomimetic aquatic plant substrate of Example 2 was prepared through the following steps: Preparation of gradient porous biochar-based fiber: Under nitrogen protection, rice husks were kept at 550℃ for 2 hours with a heating rate of 10℃ / min. The pyrolyzed agricultural waste was placed at 700℃. The remaining steps were the same as in Example 1. Preparation of functionalized fibers: Same as in Example 1; Woven imitation aquatic plant clusters: Same as Example 1; Construction of biomimetic aquatic plant substrate: Same as Example 1; Example

[0046] The biomimetic aquatic plant substrate of Example 3 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: The pore size gradient of the gradient porous biochar structure is 500 μm, 30 nm, and 1 nm. The remaining steps are the same as in Example 2. Preparation of functionalized fibers: Same as in Example 2; Woven imitation aquatic plant clusters: Same as Example 2; Constructing a biomimetic aquatic plant substrate: Same as Example 2.

[0047] Example 4 The biomimetic aquatic plant substrate of Example 4 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: The mass ratio of gradient porous biochar to polymer is 1:4, and the remaining steps are the same as in Example 3; Preparation of functionalized fibers: Same as in Example 3; Woven imitation aquatic plant clusters: Same as Example 3; Constructing a biomimetic aquatic plant substrate: Same as Example 3.

[0048] Example 5 The biomimetic aquatic plant substrate of Example 5 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: The mass ratio of gradient porous biochar to polymer is 1:6, and the remaining steps are the same as in Example 3. Preparation of functionalized fibers: Same as in Example 3; Woven imitation aquatic plant clusters: Same as Example 3; Constructing a biomimetic aquatic plant substrate: Same as Example 3.

[0049] Example 6 The biomimetic aquatic plant substrate of Example 6 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: The mass ratio of gradient porous biochar to polymer is 1:9, and the remaining steps are the same as in Example 3; Preparation of functionalized fibers: Same as in Example 3; Woven imitation aquatic plant clusters: Same as Example 3; Constructing a biomimetic aquatic plant substrate: Same as Example 3.

[0050] Example 7 The biomimetic aquatic plant substrate of Example 7 was prepared through the following steps: Preparation of gradient porous biochar-based fibers: The mass ratio of gradient porous biochar to polymer is 1:10, and the remaining steps are the same as in Example 3; Preparation of functionalized fibers: Same as in Example 3; Woven imitation aquatic plant clusters: Same as Example 3; Constructing a biomimetic aquatic plant substrate: Same as Example 3.

[0051] Examples 8-10 The difference between the biomimetic aquatic plant substrates of Examples 8-10 and Example 5 is that the diameters of the gradient porous biochar-based fibers are 0.5 mm, 1.0 mm and 2 mm, respectively, while the remaining steps are the same as in Example 5.

[0052] Example 11 The difference between the biomimetic aquatic plant matrix in Example 11 and that in Example 8 is that the gradient porous biochar-based fiber is pretreated before the functional fiber is prepared. Specifically, the gradient porous biochar-based fiber is disinfected and moistened by immersing it in 75% ethanol and then washed with deionized water.

[0053] Comparative Example 1 The difference between the biomimetic aquatic plant substrate of Comparative Example 1 and Example 1 is that the gradient porous structure biochar is replaced with biochar with a single pore size of 500 nm, while the rest of the steps are the same as in Example 1.

[0054] Comparative Example 2 The difference between the biomimetic aquatic plant substrate of Comparative Example 2 and Example 1 is that the gradient porous structure biochar is replaced with biochar with a single pore size of 1 nm, while the rest of the steps are the same as in Example 1.

[0055] Comparative Example 3 The biomimetic aquatic plant substrate of Comparative Example 3 was obtained through the following steps: S1: Preparation of nano-hydroxycopper phosphate: 20% phosphoric acid solution was added dropwise to an 8% copper acetate solution, controlling the Cu content... 2+ With PO4 3-The molar ratio of the two components was 2:1, and the pH was adjusted to 4. The mixture was placed in a reaction vessel lined with polytetrafluoroethylene and hydrothermally crystallized at 160°C for 4 hours. After washing, drying, and grinding to 50 nm, nano-hydroxy copper phosphate was obtained. S2: Preparation of biomimetic aquatic plant matrix: After heating 1 kg of polyethylene terephthalate to 280℃ until completely melted, add 0.5 kg of polybutylene terephthalate and stir until blended and melted. Then add 0.45 kg of silicon dioxide with a particle size of 120 μm, 0.03 kg of nano-hydroxy copper phosphate, 0.03 kg of silane coupling agent A-172, and 0.02 kg of ultraviolet absorber UVP-327. Stir for 8 min, pour into a mold, and hot press under the conditions of 270℃, 15 MPa, and 10 min. Cool down to 215℃ at a rate of 10℃ / min, cool and crystallize under 10 MPa pressure for 2 h, and then cool down to room temperature at a rate of 15℃ / min to obtain a biomimetic aquatic plant matrix with dimensions of 0.5 m × 1.5 m × 0.3 cm. S3: Cut sequentially along the long side (1.5m) of the biomimetic aquatic plant substrate at 5cm intervals. Stop cutting when you reach 7cm from the edge of the substrate each time to obtain a biomimetic aquatic plant substrate composed of 30 square strips.

[0056] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the biomimetic aquatic plant substrate is replaced with a 3cm diameter polyethylene hollow plastic sphere. The specific preparation method is to use an injection molding machine to heat and melt polyethylene plastic particles (brand name Shenghao Plastics, grade name FB1460) at 200°C, inject them into a spherical mold, and cool them after molding to obtain a hollow polyethylene plastic sphere with a hollow interior.

[0057] Performance Testing (Part 1) The following methods were used to test the performance of the gradient porous biochar-based fibers obtained in different Examples 1-11 and Comparative Examples 1-2, the biomimetic aquatic plant matrix obtained in Comparative Document 3, and the polyethylene hollow plastic spheres obtained in Comparative Example 4. The test results are shown in Table 1.

[0058] Specific surface area: determined using the BET method.

[0059] Table 1 Performance test results of biomimetic aquatic plant substrate

[0060] The test results in Table 1 show that the specific surface area of ​​the gradient porous biochar-based fibers obtained in this application can reach 300-800 m². 2 / g significantly increases the specific surface area of ​​gradient porous biochar-based fibers.

[0061] Combining the data detection results from Examples 1 and 2, it was found that the specific surface area of ​​the gradient porous biochar-based fiber in Example 2 was 500 m². 2 / g, higher than in Example 1, indicates that activation at temperatures above the pyrolysis temperature and deep etching of the carbon skeleton formed by pyrolysis produce gradient porous biochar with a higher specific surface area, thereby increasing the specific surface area of ​​gradient porous biochar-based fibers.

[0062] Combining the data detection results from Examples 3 and 2, it was found that the specific surface area of ​​the gradient porous biochar-based fiber in Example 3 was 550 m². 2 / g, higher than in Example 2, indicates that having a pore size gradient of 50nm-10μm, 2-50nm, and <2nm in the gradient porous biochar structure can further increase the specific surface area of ​​the gradient porous biochar-based fiber.

[0063] Based on the data detection results from Examples 3-7, it was found that the specific surface area of ​​the gradient porous biochar-based fiber in Example 5 was 800 m². 2 / g, higher than in Examples 3-4 and 6-7, indicating that controlling the mass ratio of gradient porous biochar to polymer at 1:(4-9) during blending and spinning of gradient porous biochar and polymer can further increase the specific surface area of ​​gradient porous biochar-based fibers.

[0064] Based on Example 1 and Comparative Examples 1-4, it was found that biochar with a single pore size of 1 nm or 500 nm has a lower specific surface area. Moreover, compared with the biomimetic aquatic plant matrix prepared in Comparative Example 3 and the polyethylene hollow plastic spheres prepared in Comparative Example 4, the gradient porous biochar-based fiber prepared by the method of this application has a higher specific surface area.

[0065] The following are applications of biomimetic aquatic plant substrates in water body restoration. Application Example 1 Application Example 1: The application of the biomimetic aquatic plant substrate in water body restoration is as follows: The biomimetic aquatic plant substrate obtained in Example 1 was placed on a water surface at 25℃, pH=7, and dissolved oxygen of 3mg / L. Five 1-square-meter floating frames were placed on a 100-square-meter water surface for 30 days. The initial water parameters were: ammonia nitrogen content of 8mg / L, total nitrogen content of 15mg / L, chemical oxygen demand of 120mg / L, total phosphorus content of 2mg / L, and suspended solids of 120mg / L.

[0066] Application Example 2-11 Application Example 2-11 uses the same biomimetic aquatic plant substrate as Application Example 1 in water body restoration, the difference being that the biomimetic aquatic plant substrate used is the same as that in Example 2-11.

[0067] Application Comparative Examples 1-4 The application methods of Comparative Examples 1-4 and Application Example 1 in water body restoration are the same, the difference being that the biomimetic aquatic plant substrate used in Comparative Examples 1-4 is selected respectively.

[0068] Performance Testing (Part 2) The following methods were used to test the performance of the gradient porous biochar-based fibers obtained in different Examples 1-11 and Comparative Examples 1-2, the biomimetic aquatic plant matrix obtained in Comparative Document 3, and the polyethylene hollow plastic spheres obtained in Comparative Example 4. The test results are shown in Table 2.

[0069] Biomass of biofilm: Take 10g of biomimetic aquatic plant substrate after 30 days, gently rinse with deionized water to remove non-adhesive substances, dry at 105℃ to constant weight, and weigh the total weight after cooling; then calcine in a muffle furnace at 550℃ to constant weight, cool, and weigh. The resulting weight is the ash weight. Biofilm dry weight = total dry weight - ash weight. Measure the dry weight of the biofilm.

[0070] Biofilm initiation time: Record the number of days from the addition of biomimetic aquatic plant substrate to the point where the ammonia nitrogen removal rate remains stable at 70% for 3 consecutive days.

[0071] Ammonia nitrogen removal rate: The ammonia nitrogen concentration before treatment and after 30 days of treatment was detected according to the standard HJ 535-2009 "Determination of ammonia nitrogen in water quality by Nessler's reagent spectrophotometric method". The ammonia nitrogen removal rate was calculated by combining the daily water treatment volume and the carrier filling volume. The formula is: ammonia nitrogen removal rate = (influent ammonia nitrogen concentration - effluent ammonia nitrogen concentration) × daily water treatment volume / total dry weight of carrier.

[0072] Shock recovery time: The influent ammonia nitrogen concentration is instantaneously increased to 2-3 times the baseline value for 6 consecutive hours. After the shock ends, the effluent ammonia nitrogen concentration is measured every 2-4 hours. The time taken for the concentration to recover to more than 90% of the stable level before the shock is recorded as the shock recovery time.

[0073] Table 2 Performance test results of biomimetic aquatic plant matrix for water remediation

[0074] The test results in Table 2 show that the biomass of biofilm remediation in water bodies using the biomimetic aquatic plant matrix obtained in this application is 20-60 mg / g, the biofilm initiation time is 5-14 days, the ammonia nitrogen removal rate is 3-10 mg N / (g·d), and the shock recovery time is 12-36 h. This significantly improves the efficiency of microbial immobilization and pollutant removal, provides a sustainable supply of growth promoters, and effectively activates the metabolic activity of functional microorganisms, thereby enhancing the system's shock resistance.

[0075] Combining the data from Application Example 1 and Application Example 2, it was found that the biomass of biofilm remediation in Application Example 2 using the biomimetic aquatic plant substrate was 25 mg / g, and the ammonia nitrogen removal rate was 4 mg N / (g·d), both of which were higher than those in Application Example 1. The biofilm initiation time was 12 days, and the shock resistance recovery time was 32 h, both of which were lower than those in Application Example 1. This indicates that activation at temperatures above the pyrolysis temperature can improve the efficiency of microbial immobilization and pollutant removal, and enhance the system's shock resistance.

[0076] Combining the data from Application Examples 2 and 3, it was found that the biomass of biofilm remediation using the biomimetic aquatic plant matrix in Application Example 3 was 30 mg / g, and the ammonia nitrogen removal rate was 5 mg N / (g·d), both higher than those in Application Example 2. The biofilm initiation time was 10 days, and the shock resistance recovery time was 29 h, both lower than those in Application Example 2. This indicates that using gradient porous biochar with pore size gradients of 50 nm-10 μm, 2-50 nm, and <2 nm can further improve the efficiency of microbial immobilization and pollutant removal, and enhance the system's shock resistance.

[0077] Based on the data from Application Examples 3-7, it was found that the biomass of biofilm remediation using the biomimetic aquatic plant matrix in Application Examples 4-6 was 35-40 mg / g, and the ammonia nitrogen removal rate was 6-7 mg N / (g·d), both higher than those in Application Examples 3 and 7. The biofilm initiation time was 8-9 days, and the shock resistance recovery time was 20-25 h, both lower than those in Application Examples 3 and 7. This indicates that controlling the mass ratio of gradient porous biochar to polymer at 1:(4-9) during the blending and spinning of gradient porous biochar and polymer can further improve the efficiency of microbial immobilization and pollutant removal, and enhance the system's shock resistance.

[0078] Combining the data from Application Examples 8-10, it was found that the biomass of biofilm remediation using the biomimetic aquatic plant matrix in Application Example 9 was 50 mg / g, and the ammonia nitrogen removal rate was 9 mg N / (g·d), both higher than those in Application Examples 8 and 10. The biofilm initiation time was 6 days, and the shock resistance recovery time was 14 hours, both lower than those in Application Examples 8 and 10. This indicates that controlling the diameter of the gradient porous biochar-based fiber to 0.5 mm can further improve the microbial immobilization efficiency and pollutant removal effect, and enhance the system's shock resistance.

[0079] Combining the data from Application Example 9 and Application Example 11, it was found that the biomass of biofilm remediation in Application Example 11 using the biomimetic aquatic plant matrix was 60 mg / g, and the ammonia nitrogen removal rate was 10 mg N / (g·d), both of which were higher than those in Application Example 9. The biofilm initiation time was 5 days, and the shock resistance recovery time was 12 hours, both of which were lower than those in Application Example 7. This indicates that pretreatment of gradient porous biochar-based fibers before the preparation of functional fibers can further improve the efficiency of microbial immobilization and pollutant removal, and enhance the system's shock resistance.

[0080] Combining the data from Application Example 1 and Comparative Examples 1-4, it was found that fabricating gradient porous biochar into biochar with a single pore size of 1 nm or 500 nm reduced the microbial immobilization efficiency and pollutant removal effect, and also decreased the system's shock resistance. Furthermore, compared to the biomimetic aquatic plant matrix obtained in Comparative Document 3 and the polyethylene hollow spheres obtained in Comparative Example 4, the biomimetic aquatic plant matrix obtained in this application significantly improved the microbial immobilization efficiency and pollutant removal effect, and enhanced the system's shock resistance.

[0081] The biomimetic aquatic plant substrate of this application features a modular design, which enables the equipment to have engineering advantages such as rapid deployment, easy monitoring and maintenance, and reusability, greatly improving the flexibility and management efficiency of water body restoration.

[0082] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions, characterized in that, The biomimetic aquatic plant substrate is prepared through the following steps: Preparation of gradient porous biochar-based fibers: Agricultural waste is pyrolyzed and activated to produce gradient porous biochar. The gradient porous biochar is then blended with a polymer and spun to obtain gradient porous biochar-based fibers. Preparation of functionalized fibers: Gradient porous biochar-based fibers were immersed in MES buffer containing crosslinking agent and catalyst at pH 5.5 and activated by shaking at 25℃ for 30 min. The gradient porous biochar-based fibers were then removed and transferred to a mixed aqueous solution containing polyglutamic acid and microbial promoter. The reaction was carried out at 25-30℃ and pH 6.0-7.0 for 4-6 h. The fibers were washed with deionized water and stored at 4℃ to obtain functionalized fibers. Woven aquatic plant clusters: Functional fibers are woven into aquatic plant clusters with a three-dimensional branching structure and a height of 10-200cm. Constructing a modular biomimetic aquatic plant substrate: Multiple biomimetic aquatic plant clusters are fixed to a floating frame equipped with an anchoring system to obtain a modular biomimetic aquatic plant substrate.

2. The biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions according to claim 1, characterized in that, The pyrolysis specifically involves: placing agricultural waste at 400-700℃ for 1-3 hours under inert gas protection, with a heating rate of 5-20℃ / min; the activation specifically involves placing the pyrolyzed agricultural waste at 600-900℃ and activating it under steam for 1-2 hours, followed by washing and drying.

3. The biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions according to claim 1, characterized in that, The pore size gradient of the gradient porous biochar is 50nm-10μm, 2-50nm, and <2nm.

4. The biomimetic aquatic plant substrate with slow-release and biofilm culture functions according to claim 1, characterized in that, When the gradient porous biochar and polymer are blended and spun, the mass ratio of the gradient porous biochar to the polymer is controlled at 1:(4-9).

5. The biomimetic aquatic plant substrate with slow-release and biofilm culture functions according to claim 1, characterized in that, The polymer is selected from any one or more of polycaprolactone, polyvinyl alcohol, and polylactic acid.

6. The biomimetic aquatic plant substrate with slow-release and biofilm culture functions according to claim 1, characterized in that, The gradient porous structure biochar blend spinning with polymer includes the following steps: S1. Dissolve the polymer in an organic solvent and stir until completely dissolved. Add dried gradient porous biochar, disperse evenly, and degas to obtain the spinning solution. S2. Inject the spinning solution at a temperature of 25-35℃ into the spinning pump, extrude it through a spinneret with an orifice diameter of 0.3-0.5mm, and enter the coagulation bath for 2-5 minutes at a temperature of 20-30℃ to form nascent fibers. S3. The nascent fibers are stretched 1.5-3 times at a stretching speed of 5-10 m / min, then dried and shaped at 40-60℃, and wound up to obtain gradient porous biochar-based fibers.

7. The biomimetic aquatic plant substrate with slow-release and biofilm culture functions according to claim 1, characterized in that, The gradient porous biochar-based fiber has a diameter of 0.1-2.0 mm.

8. The biomimetic aquatic plant substrate with slow-release and biofilm culture functions according to claim 1, characterized in that, The microbial promoter is selected from one or more of the following: denitrification promoter, polyphosphate promoter, microbial quorum sensing signal molecule, trace element complex, rhamnolipid, and anthraquinone-2-sulfonate.

9. The biomimetic aquatic plant substrate with slow-release and biofilm cultivation functions according to claim 1, characterized in that, Before preparing the functionalized fiber, the gradient porous biochar-based fiber is pretreated by immersing it in 75% ethanol for disinfection and wetting, and then washing it with deionized water.

10. The application of a biomimetic aquatic plant substrate with slow-release and biofilm culture functions as described in any one of claims 1-9.

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