Bioremediation material for contaminated water body and preparation method and application thereof

Abstract

The present application belongs to the technical field of contaminated water body remediation, and particularly relates to a contaminated water body bioremediation material, a preparation method and application thereof. The remediation material comprises polypropylene fibers, metasilicic acid gel, a reducing iron salt and nitzschia closterium, wherein the polypropylene fibers are loaded with metasilicic acid gel on the surface and crosslinked with the reducing iron salt, and the nitzschia closterium is wrapped on the surface of the polypropylene fibers loaded with metasilicic acid gel and crosslinked with the reducing iron salt. The remediation material utilizes the hydrogen peroxide released by the nitzschia closterium during growth to generate oxidizing hydroxyl radicals to degrade pollutants. The metasilicic acid gel crosslinked with the reducing iron salt has no oxidizing property and is non-toxic to aquatic organisms, and does not destroy the original ecological system balance of the water body. Moreover, the remediation material does not flow away with the water flow and needs no continuous addition.

Description

Technical Field

[0001] This invention belongs to the field of polluted water remediation technology, specifically relating to a bioremediation material for polluted water, its preparation method, and its application. Background Technology

[0002] In recent years, the widespread use of everyday chemically synthesized products has led to the discharge of wastewater containing persistent organic pollutants (persistent organic pollutants are generally organic chemicals that are difficult for organisms to decompose or degrade under natural conditions) into surface water bodies, causing serious water pollution. Tests have revealed that common persistent organic pollutants in surface water include antibiotics, surfactants, dyes, and synthetic pesticides. These pollutants are often carcinogenic, teratogenic, and mutagenic, and can persist in the aquatic environment for extended periods, accumulating in organisms and posing a potential threat to ecosystem function and human health. Furthermore, domestic wastewater from toilet flushing, bathing, and cooking, as well as the widespread use of chemical fertilizers in agricultural production, results in wastewater rich in nutrients such as nitrogen and phosphorus being discharged into surface water bodies through sewage treatment plant outlets, stormwater and sewage pipe networks, and agricultural runoff. This leads to eutrophication and even oxygen depletion and black, foul-smelling water bodies. The deterioration of water quality in these black and foul-smelling water bodies makes it difficult for organisms to survive, resulting in low biodiversity, severe disruption of the aquatic ecological balance, and the loss of the water body's usability and ecological value.

[0003] Currently, remediation materials for polluted water bodies mainly fall into two categories: chemical reagents with oxidative flocculation effects and microbial agents primarily composed of bacteria and fungi. Chemical reagents generally contain aluminum, polyacrylamide, and other components, as well as highly oxidizing agents containing potassium permanganate and sodium hypochlorite. Reagents containing aluminum and polyacrylamide can react with phosphorus in the water to form flocculent substances that precipitate at the bottom of the water body. Reagents containing potassium permanganate and sodium hypochlorite can oxidize recalcitrant substances in the water into carbon dioxide, thus removing organic matter. However, chemical reagents have a short onset time and are easily washed away by water flow, often requiring continuous addition to maintain water quality, resulting in high costs. Furthermore, the large-scale addition of chemical reagents can poison aquatic organisms and disrupt the balance of the aquatic ecosystem. Microbial agents utilize bacteria and fungi in the agents to degrade pollutants in water. However, these agents are often rich in nutrients for microbial growth, which can lead to an increase in nitrogen and phosphorus in the water, causing water quality deterioration and problems such as cyanobacterial blooms or black and smelly water. Furthermore, microbial agents are easily washed away by water flow and cannot maintain a long-term restorative effect on the water body.

[0004] Therefore, it is necessary to develop an environmentally friendly remediation material that does not require continuous addition. Summary of the Invention

[0005] This invention provides a bioremediation agent based on *Nyctaginosa*, which removes pollutants from water bodies through the growth and absorption of *Nyctaginosa* and the bioFenton reaction, achieving the purpose of water purification and ecological restoration. This bioremediation agent is environmentally friendly and not easily washed away by water flow, avoiding the problem of continuous addition required by chemical or microbial remediation agents.

[0006] To achieve the above objectives, the present invention can adopt the following technical solutions:

[0007] The present invention provides a bioremediation material for polluted water bodies, comprising polypropylene fibers, metasilicic acid gel, reduced iron salt and zephyranthes, wherein the surface of the polypropylene fibers is loaded with metasilicic acid gel and cross-linked with the reduced iron salt, and the zephyranthes is wrapped around the surface of the polypropylene fibers loaded with metasilicic acid gel and cross-linked with the reduced iron salt.

[0008] Another aspect of the present invention provides a method for preparing a bioremediation material for polluted water bodies, comprising: (1) immersing polypropylene fibers in a sodium silicate solution, adding HCl solution dropwise, allowing it to stand, and loading metasilicic acid gel onto the surface of the polypropylene fibers to obtain a precursor a of the remediation material; (2) immersing the precursor a of the remediation material in a reducing iron salt solution, and cross-linking the reducing iron salt with the metasilicic acid gel to obtain a precursor b of the remediation material; (3) immersing the precursor b of the remediation material in a concentrated solution of rhombic algae, and having the rhombic algae coat the surface of the precursor b of the remediation material to obtain a bioremediation material for polluted water bodies.

[0009] In another aspect, the present invention provides a contaminated water body remediation device, which includes the above-mentioned contaminated water body bioremediation material and a carrier, wherein the contaminated water body bioremediation material is disposed on the carrier.

[0010] In another aspect, the present invention provides a method for repairing polluted water bodies, comprising: vertically fixing the above-mentioned polluted water body repair device in the polluted water body, wherein there is ≥1 polluted water body repair device, the length of the repair material on the support member from the end closest to the water surface to the end furthest from the water surface is ≥0.8m, and the total projected area of ​​the repair material accounts for ≥20% of the water surface area.

[0011] The beneficial effects of this invention include at least the following:

[0012] (1) The bioremediation material for polluted water bodies provided by the present invention is different from chemical remediation materials containing a large amount of strong oxidizing agents. The remediation material in the present invention utilizes hydrogen peroxide released by the algae during its growth to generate oxidizing hydroxyl free radicals to degrade pollutants. The cross-linked reducing iron metasilicic acid gel does not have oxidizing properties, is non-biotoxic to aquatic organisms, and will not disrupt the original ecosystem balance of the water body.

[0013] (2) The bioremediation material for polluted water bodies provided by the present invention can dynamically adjust its pollutant degradation capacity according to the water quality status. For example, when the water body is severely polluted and the concentration of nitrogen and phosphorus is high, the rhomboid algae in the bioremediation material absorbs high concentrations of nitrogen and phosphorus and grows rapidly, thereby releasing a large amount of hydrogen peroxide to degrade organic pollutants. After the water body is repaired and the water quality is improved, the rhomboid algae in the bioremediation material grows slowly due to the decrease in the concentration of nitrogen and phosphorus in the water body, and the release of hydrogen peroxide decreases. When the water body is repaired but the water quality rebounds, the rhomboid algae can absorb the increased nitrogen and phosphorus in the water body and stimulate the release of hydrogen peroxide. Therefore, the bioremediation material in the present invention does not have the problem of excessive and continuous addition of chemical or microbial remediation materials. It can avoid excessive and multiple additions through the above degradation capacity adjustment mechanism, and can achieve long-term maintenance of the remediation effect with one-time setting, saving remediation and operation and maintenance costs.

[0014] (3) The bioremediation material for polluted water bodies in this invention can be uniformly and persistently dispersed in polluted water bodies (polluted water areas or water bodies of processors or purification pools, ponds, and reservoirs). It does not have the problems of easy sedimentation or loss of microorganisms in chemical or microbial remediation materials, or short-term purification effect. That is, the bioremediation material of this invention will not be lost with the water flow, and it can exert a purification effect from the water surface to the bottom of the water body. Attached Figure Description

[0015] Figure 1 These are actual images of the bioremediation material before and after use in embodiments of the present invention, wherein a is an actual image before use and b is an actual image after use;

[0016] Figure 2 These are electron microscope images of the biorepair material before and after use in the embodiments of the present invention, wherein a is an electron microscope image before use and b is an electron microscope image after use.

[0017] Figure 3 This is a diagram showing the effect of the bioremediation material on tetracycline removal in an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of the processor structure used in an embodiment of the present invention, wherein 1: carrier, 2: bioremediation material, 3: anti-floating component, 4: overflow pipe, 5: drain pipe, 6: inlet pipe, and 7: outlet pipe;

[0019] Figure 5 This is a physical diagram of the processor used in the embodiments of the present invention;

[0020] Figure 6 The diagram shows the COD removal effect of the bioremediation material in this embodiment of the invention.

[0021] Figure 7 This is a diagram showing the effect of the bioremediation material on TN removal in an embodiment of the present invention;

[0022] Figure 8 The image shows the effect of the bioremediation material on TP removal in the embodiments of the present invention.

[0023] Figure 9 This is an example of the growth of rhomboid algae cells during use of the bioremediation material in this invention embodiment;

[0024] Figure 10 Bioremediation materials prepared from sodium silicate with different moduli;

[0025] Figure 11 The image shows a physical representation of the filamentous biorepair material used in an embodiment of the present invention.

[0026] Figure 12 In this embodiment of the invention, the concentration of *Nyctaginus* cells is 10. 7 Microscopic observation at cell / mL;

[0027] Figure 13 This is an example of what happens when rhomboid algae cells encapsulate polypropylene fibers in an embodiment of the present invention. Detailed Implementation

[0028] The embodiments described are provided to better illustrate the present invention, but are not intended to limit the scope of the invention to the embodiments described. Therefore, non-essential improvements and adjustments made to the embodiments by those skilled in the art based on the above description are still within the scope of protection of the present invention.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless they have a distinct meaning in the context. As used herein, it should be understood that terms such as “comprising,” “having,” “including,” are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials, or combinations thereof. The terminology of the invention is disclosed in the specification and is not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials, or combinations thereof may be present or added. As used herein, “ / ” may be interpreted as “and” or “or,” depending on the context.

[0030] This invention provides a bioremediation material for polluted water bodies, comprising polypropylene fibers, metasilicic acid gel, reduced iron salt, and rhombic algae. The surface of the polypropylene fibers is loaded with metasilicic acid gel and cross-linked with the reduced iron salt. The rhombic algae are wrapped around the surface of the polypropylene fibers loaded with metasilicic acid gel and cross-linked with the reduced iron salt.

[0031] It should be noted that the term "Nitzschia" in this invention refers to all algae within the genus *Nitzschia*. Specifically, *Nitzschia* is a group of single-celled algae with a unique siliceous cell wall structure, comprising 350 species. During photosynthetic growth, *Nitzschia* produces hydrogen peroxide, and the silica in its cell wall protects it from damage caused by hydroxyl radicals, strong oxidants produced by the decomposition of hydrogen peroxide. The siliceous cell wall of *Nitzschia* also has a porous structure, allowing it to not only combine with solid substrates in the environment as attachment sites but also adsorb pollutants from the water. *Nitzschia* exhibits high photosynthetic efficiency and rapid growth, quickly absorbing nitrogen and phosphorus from the water for growth, thus playing a role in purifying water quality and maintaining the ecological balance of aquatic bodies. *Nitzschia* is rich in nutrients such as unsaturated fatty acids, proteins, and amino acids, making it an important food source for aquatic organisms and a raw material for human nutritional supplements, thus belonging to beneficial algae with practical economic value.

[0032] It should also be noted that in this invention, hydrogen peroxide released by the growth of the nigrum algae is converted into highly oxidizing hydroxyl radicals, which can oxidize and remove recalcitrant organic matter in the water. At the same time, nitrogen and phosphorus in the water are absorbed for the nigrum algae's own cell synthesis, which can be preyed upon by fish or harvested to make health products. This process removes nutrients such as nitrogen and phosphorus from the water, thereby achieving water purification and ecological restoration of surface water bodies.

[0033] This invention also provides a method for preparing a bioremediation material for polluted water bodies, comprising: (1) immersing polypropylene fibers in a sodium silicate solution, adding HCl solution, allowing it to stand, and loading metasilicic acid gel onto the surface of the polypropylene fibers to obtain a precursor a of the remediation material; (2) immersing the precursor a of the remediation material in a reducing iron salt solution, and cross-linking the reducing iron salt with the metasilicic acid gel to obtain a precursor b of the remediation material; (3) immersing the precursor b of the remediation material in a concentrated solution of *Nyctaginus spp.*, and having *Nyctaginus spp.* coat the surface of the precursor b of the remediation material to obtain a bioremediation material for polluted water bodies.

[0034] In some specific embodiments, the modulus of sodium silicate in step (1) above can be ≥2.5. It should be noted that the modulus of sodium silicate in this invention has a difference in the morphology and function of the prepared bioremediation material. When the modulus of sodium silicate is less than 2.5, the generated metasilicic acid gel has low viscosity and does not bond tightly with the polypropylene fiber load; furthermore, the metasilicic acid gel generated with sodium silicate with a modulus lower than 2.5 dissolves quickly in water and cannot achieve the function required by this remediation agent to slowly release silicon elements in water for the growth of nigrum algae and continuously generate hydrogen peroxide.

[0035] In some specific embodiments, the modulus of the sodium silicate can be 2.5-3.4. For example, 2.6-3.3, 2.7-3.2, 2.8-3, 2.9, 3, or 3.1, etc. It should be noted that the maximum theoretical modulus of sodium silicate and the modulus of commercially available raw materials is currently 3.4, so the modulus of sodium silicate in this invention can be 2.5-3.4.

[0036] In some specific embodiments, in step (1) above, the concentration of the HCl solution can be 3mol / L-7mol / L, such as 4mol / L-6mol / L, 5mol / L-7mol / L, 4mol / L or 5mol / L, etc.

[0037] It should be noted that, in this invention, the preferred concentration of the HCl solution is 3 mol / L to 7 mol / L. This allows the sodium silicate and HCl to react at a moderate rate, undergoing a "water glass" reaction to generate metasilicic acid gel, which is then more uniformly loaded onto the surface of the polypropylene fibers. This ensures that the bio-modified material continuously and uniformly generates hydrogen peroxide in the water, oxidizing and degrading pollutants. If the HCl solution concentration is too low (less than 3 mol / L), the reaction rate is too slow, which is detrimental to the subsequent loading process, and the loaded metasilicic acid gel is not very uniform. If the HCl solution concentration is too high (greater than 7 mol / L), the reaction rate is too fast, and the generated metasilicic acid gel contains a large amount of unreacted sodium silicate due to mass transfer limitations in the chemical reaction, which is also detrimental to the uniform loading of the metasilicic acid gel. When the HCl solution concentration is 3 mol / L to 7 mol / L, the reaction rate is suitable, and the generated metasilicic acid gel is loaded more uniformly.

[0038] In some specific embodiments, in step (1) above, the mass ratio of sodium silicate to HCl can be >1:1, such as 1.1:1, 1.5:1, 2:1 or 3:1.

[0039] It should be noted that the mass ratio of sodium silicate to HCl is also a factor affecting the reaction rate of sodium silicate and HCl. When the mass of HCl is greater than the mass of sodium silicate, the chemical reaction proceeds more completely, and there is less unreacted sodium silicate, which is more conducive to the uniform loading of the generated metasilicic acid gel on the surface of polypropylene fibers. Therefore, in this invention, the preferred mass ratio of sodium silicate to HCl is >1:1.

[0040] In some specific embodiments, in step (2) above, the reducing iron salt can be a divalent iron salt.

[0041] It should be noted that the standard chemical equation for the Fenton reaction is: Fe 2+ +H₂O₂→Fe 3+ +OH·+OH -That is, ferrous salts (reduced ferric salts) act as reducing agents, and hydrogen peroxide acts as an oxidizing agent, resulting in a redox reaction that produces ferric iron, hydroxyl radicals (OH·), and hydroxide ions (OH·). - Since ferrous salts act as reducing agents in the reaction, the reducing ferrous salts in this invention are ferrous salts.

[0042] It should be noted that the aforementioned reducing iron salts can be those known in the art, such as ferrous sulfate, ferrous chloride, ferrous nitrate, ferrous carbonate, or ferrous acetate, and can be selected according to specific needs.

[0043] In some specific embodiments, in step (3) above, the concentration of *Nyctaginea* cells in the concentrated *Nyctaginea* solution can be ≥1×102 7 cell / ml.

[0044] It should be noted that, based on the "Allee Effect" principle in ecology (i.e., a population cannot grow or survive in an ecosystem if its initial population size is too sparse), *Nyctaginea*, although a widespread algae in water, cannot perform its purification function. Specifically, although *Nyctaginea* may exist in the water, its initial population may be too low, and without a continuous supply of silicon, its population cannot grow effectively. In this invention, based on this consideration, the concentration of *Nyctaginea* cells coated on the polypropylene fiber should not be too low to ensure its growth after being placed in water; experiments have shown that the concentration of *Nyctaginea* cells should be at least 10. 7 For the purification effect of the repair material to be relatively rapid, it needs to be on the order of cells / mL. Furthermore, it was found that a cell concentration of 10... 7 More than 10 cells / mL (at least 10) 7 Only when the concentration of *Nyctaginus* cells is ≥1 × 10⁻⁶ cells / mL can the *Nyctaginus* cells completely coat the surface of the polypropylene fiber, resulting in a high efficiency in the Fenton reaction and degradation of pollutants. Therefore, in this invention, the concentration of *Nyctaginus* cells can be ≥1 × 10⁻⁶ cells / mL. 7 cell / ml, for example 1.3×10 7 cell / ml, 1.5×10 7 cell / ml or 2×10 7 cell / ml, etc.

[0045] It should also be noted that the higher the concentration of the *Nyctaginus* cell concentrate in this invention, the more *Nyctaginus* cells will be attached and coated, and the more highly oxidizing hydroxyl radicals will be generated. However, those skilled in the art should know that the growth of *Nyctaginus* (and other algae) has a saturation point; in this invention, the saturation point for *Nyctaginus* is 2 × 10⁻⁶. 9 cell / ml.

[0046] In some specific embodiments, in step (2) above, the mass ratio of sodium silicate to HCl can be >1:1. The precursor a of the repair material is washed with deionized water until the pH of the washing solution is >7.5, and then soaked in a reducing iron salt solution.

[0047] It should be noted that, in this invention, it was found that the chemical reaction proceeds more completely when the mass of HCl is greater than that of sodium silicate, resulting in less unreacted sodium silicate and making it easier for the generated metasilicic acid gel to be uniformly loaded on the surface of polypropylene fibers. However, excessive HCl can cause the pH of the prepared material to be too low. Therefore, it is necessary to wash the material with deionized water after the reaction until the pH of the washing solution is greater than 7.5 to solve the problem of low pH.

[0048] In some specific embodiments, in step (2) above, the repair material precursor a is immersed in a reducing iron salt solution for ≥12h.

[0049] It should be noted that the soaking time of the repair material precursor a in the reducing iron salt solution can be selected according to the specific situation, preferably ≥12, such as 13h, 15h or 17h.

[0050] In some specific embodiments, in step (3) above, the repair material precursor b is soaked in the concentrated solution of Rhizoctonia solani for ≥1 hour.

[0051] It should be noted that the soaking time of the repair material precursor b in the concentrated solution of *Nyctaginosa* can be set to more than 1 hour, such as 1.5 hours, 2 hours, or 2.5 hours, depending on the specific reaction conditions.

[0052] In some specific embodiments, the method for preparing sodium silicate solution in step (1) above includes: adding sodium silicate to deionized water, stirring to dissolve it, letting it stand, cooling it, and preparing sodium silicate solution; wherein, the stirring temperature is >40℃, and the mass ratio of sodium silicate to deionized water is <1:2.

[0053] It should be noted that in this invention, the sodium silicate can only be completely dissolved when the mass of deionized water is greater than 1.8 times (including 1.8 times) the mass of sodium silicate. Therefore, the preferred mass ratio of sodium silicate to deionized water in this invention is <1:2.

[0054] This invention provides a device for remediating contaminated water bodies, which includes the aforementioned bioremediation material for contaminated water bodies and a carrier, wherein the bioremediation material for contaminated water bodies is disposed on the carrier.

[0055] Specifically, refer to Figure 4The bioremediation material for contaminated water bodies described in this invention can be mounted on a carrier to create a contaminated water body remediation device for use in the remediation of contaminated water bodies. It should be understood that the mounting method can be either directly binding it to the carrier, or first fixing the bioremediation material to a fixing component, and then connecting the fixing component to the carrier, or it can be configured to be detachable.

[0056] In some specific embodiments, the above-mentioned bioremediation material for polluted water can be woven into different shapes as a unit, with ≥2 units, and single units or multiple units are connected in series on the carrier at intervals.

[0057] It should be noted that the bioremediation material for contaminated water is in the form of filaments. Multiple filaments of bioremediation material can be woven into a specific shape as a unit, and then different shaped units of bioremediation material can be strung together at intervals on a carrier.

[0058] In some specific embodiments, the different shapes described above may include rope-like, cloth-like, or radial shapes. It should be noted that the different shapes described above can be woven according to specific needs, such as rope-like, cloth-like, or radial shapes.

[0059] In some specific embodiments, the aforementioned carrier can be a flexible strip. It should be noted that the aforementioned carrier can be a rigid component or a flexible strip, with a preference for a flexible component, as flexible strips are readily available and inexpensive, such as nylon rope.

[0060] In some specific embodiments, the aforementioned carrier can be a flexible strip, and an anti-floating component is also provided at the end of the carrier away from the water surface. It should be noted that, in order to prevent the flexible strip from floating on the water surface, an anti-floating component can be provided at the end of the flexible strip away from the water surface. The anti-floating component can be any component that allows the flexible strip to float on the water surface, and its shape is not limited, such as square, spherical, or other irregular shapes.

[0061] This invention also provides a method for repairing polluted water bodies, comprising: vertically fixing the above-mentioned polluted water body repair device in the polluted water body, wherein there is ≥1 polluted water body repair device, the length of the repair material on the support from the end closest to the water surface to the end furthest from the water surface is ≥0.8m, and the total projected area of ​​the repair material accounts for ≥20% of the water surface area.

[0062] It should be noted that the "length of the repair material on the support from the end closest to the water surface to the end furthest from the water surface" refers to the length of the repair material occupying the support, including the spacing between the repair materials. The dosage (treatment load) of the repair material is determined by the "length of the repair material on the support from the end closest to the water surface to the end furthest from the water surface" and the "proportion of the total projected area of ​​the repair material to the water surface area." Furthermore, the spacing between the repair materials can be 8cm-20cm.

[0063] It should be noted that the polluted water body in this invention refers to surface water bodies polluted by recalcitrant organic matter, nitrogen, phosphorus, etc., including polluted water areas, processors or purification ponds for treating polluted water, polluted ponds, and polluted reservoirs.

[0064] To better understand the present invention, specific examples are provided below to further illustrate the content of the present invention, but the content of the present invention is not limited to the examples below.

[0065] Example 1: Preparation of Bioremediation Materials

[0066] Sodium silicate with a modulus of 3.0 was added to deionized water at a mass ratio of 1:2.5. After dissolving by stirring at 55°C, the solution was allowed to stand for 10 minutes and then cooled to prepare a saturated sodium silicate solution. Polypropylene fibers were then immersed in the saturated sodium silicate solution, and 5 mol / L HCl was slowly added dropwise at a mass ratio of 1:1.5 (sodium silicate to HCl). After standing for 3 minutes, a metasilicic acid gel formed on the surface of the polypropylene fibers. The metasilicic acid gel on the surface of the polypropylene fibers was rinsed with deionized water for 3 minutes until the pH of the cleaning solution reached 8.0. The fibers were then immersed in a saturated ferrous sulfate solution for 15 hours to ensure cross-linking between ferrous ions and the metasilicic acid gel. Under light-proof and undisturbed conditions, the cross-linked polypropylene fibers were immersed in a 1×10⁻⁶ solution. 8 Filamentous bioremediation material was prepared by immersing the algae in a solution of *Rhizoctonia solani* (cell / mL) for 2 hours, allowing the algae to coat the surface of the fibers.

[0067] In addition, 40 of the above-prepared filamentous biorepair materials are bound and fixed onto a 10cm diameter polypropylene plastic ring to obtain a radial unit of biorepair material.

[0068] Example 2: Experiment on the effect of bioremediation material group on tetracycline removal

[0069] Tetracycline is a typical recalcitrant organic pollutant that is most frequently detected and has a high concentration in surface water. Therefore, this invention investigated the removal rate of tetracycline by the prepared bioremediation material, as follows:

[0070] One radial unit of the bioremediation material prepared in Example 1 was placed in 500 mL of contaminated water with a tetracycline concentration of 0.8 mg / L, serving as the bioremediation material group. In addition, a blank control group with the same tetracycline concentration but without the addition of bioremediation material was set up. The effect of the bioremediation material on the removal of tetracycline in water was investigated by comparing the changes in tetracycline concentration between the bioremediation material group and the blank control group.

[0071] Photos of the bio-repair material before and after use are attached. Figure 1 As shown, surface features were analyzed using scanning electron microscopy, and the resulting electron microscope images are attached. Figure 2 As shown; in addition, the concentration of tetracycline in the solution was determined using DB37 / T 3632—20, and the data for each group are attached. Figure 3 As shown in the figure; in addition, the tetracycline concentration at the beginning of the experiment (0d) was subtracted from the tetracycline concentration at the end of the experiment (7d) in both the bioremediation material group and the blank control group, and then divided by the tetracycline concentration at the beginning of the experiment to calculate the removal rate of tetracycline in the bioremediation material group and the blank control group, respectively. The results showed that the removal rate of tetracycline in the bioremediation material group was 59.2%, which was much higher than that in the blank control group, indicating that the bioremediation material has a significant remediation effect on tetracycline-contaminated water bodies.

[0072] Example 3: Test on the removal effects of bioremediation materials on COD, TN, and TP

[0073] Twenty radial units of the bioremediation material prepared in Example 1, evenly spaced (8 cm) together, were connected in series on a nylon rope and placed in a cylindrical processor with a volume of 35 L. One end of the nylon rope was fixed to the top of the processor, and the other end was fixed to an anti-floating component at the bottom of the processor. A water pump continuously fed the polluted reservoir water to be treated into the processor through the inlet pipe at the bottom of the processor. The polluted reservoir water was purified by flowing through the bioremediation material vertically fixed to the processor and discharged through the outlet pipe at the top of the processor. After treatment, all the water could be drained through the drain pipe. To prevent overflow caused by fluctuations in the inlet water volume during treatment, an overflow pipe was installed to control the maximum safe water level of the processor. The schematic diagram and physical image of the processor are shown below. Figure 4 and Figure 5 As shown; in addition, a cylindrical processor without added bioremediation material was set up, maintaining the same influent and operating conditions, as a blank control group.

[0074] The purification and remediation effects of bioremediation materials on the raw water of a polluted reservoir were investigated by comparing the concentrations of COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) in the effluent of the bioremediation material group and the blank control group. Specifically, samples were taken from the effluent outlets of the processors in both the bioremediation material group and the blank control group on days 0, 2, 4, 7, 10, 14, 18, 23, and 28 of operation, and the concentrations of COD, TN, and TP in the effluent were measured using methods specified in HJ 636—2012, GB / T 11893—1989, and GB / T 11894—1989, respectively.

[0075] The changes in COD, TN, and TP concentrations in each group are as follows: Figure 6 , Figure 7 and Figure 8 As shown; in addition, the concentrations of each pollutant at the beginning of the experiment (0d) were subtracted from the pollutant concentrations of the bioremediation material group and the blank control group after stable operation (≥10d), and then divided by the pollutant concentrations at the beginning of the experiment. The removal rates of each pollutant in the bioremediation material group and the blank control group were calculated respectively. The results showed that the removal rates of COD, TN and TP in the bioremediation material group could reach 24.2%, 68.1% and 57.6% and above, respectively, which were much higher than those in the blank group. This indicates that the processor with bioremediation material has a significant purification and remediation effect on the raw water of the polluted reservoir.

[0076] In addition, the growth curves of *Nyctaginosa* in the bioremediation material group and the control group are attached. Figure 9 As shown, because the raw water of the polluted reservoir already contained a small amount of nigrum algae, nigrum algae were detected in both the bioremediation material group and the control group at the beginning of the experiment (0 days); after the processor had been running for 4 days, the amount of nigrum algae in the bioremediation material group reached 7.7 × 10⁻⁶. 7 The concentration of cells / L was significantly higher than the 1.6 × 10⁻⁶ in the control group. 7 The concentration of per liter indicates that the metasilicic acid gel provides the silicon element required for the synthesis of silica cell walls in *Nyctaginea*, promoting the photosynthetic growth of *Nyctaginea* and absorbing and removing TN and TP from the polluted reservoir raw water. At the same time, the hydrogen peroxide released by the growth of *Nyctaginea* and the reducing iron salts in the bioremediation material trigger a bio-Fenton reaction, and the generated strong oxidizing hydroxyl radicals degrade COD in the polluted reservoir raw water.

[0077] Example 4: Modulus Screening of Sodium Silicate

[0078] In Example 1, the sodium silicate used to prepare the bioremediation material was replaced with sodium silicate with moduli ranging from 1 to 3.4. In this example, sodium silicate with moduli of 1.5, 2.0, 2.5, and 3.4 was selected. Other steps were the same as in Example 1, resulting in different bioremediation materials. The preparation results are as follows: Figure 10As shown in the figure (A represents the case with a modulus of 1.5, B represents the case with a modulus of 2.0, C represents the case with a modulus of 2.5, and D represents the case with a modulus of 3.4), it can be seen from the figure that although sodium silicate of all moduli can dissolve and react with HCl, when the modulus is below 2.5, the resulting metasilicic acid gel has low viscosity. Figure 10 A and B) do not bond tightly with the polypropylene fiber load; and the metasilicic acid gel generated by sodium silicate with a modulus lower than 2.5 dissolves quickly in water, failing to achieve the function required by this remediation agent to slowly release silicon elements in the water to support the growth of nigrum algae and to continuously generate hydrogen peroxide.

[0079] Example 5: Screening based on the mass ratio of sodium silicate to deionized water

[0080] The mass ratio of sodium silicate to deionized water in the preparation of bioremediation materials in Example 1 was replaced with other ratios. In this example, the mass ratios of sodium silicate to deionized water were 1:1.2, 1:1.4, 1:1.6, 1:1.8, and 1:2.0, respectively. The other steps were the same as in Example 1 to prepare different bioremediation materials. The results showed that when the modulus of sodium silicate was 3, at least 1.8 times more deionized water was required to completely dissolve the sodium silicate. That is, the higher the modulus of sodium silicate, the lower its solubility, and therefore more deionized water is required to dissolve it.

[0081] Example 6: HCl Concentration Screening

[0082] The HCl concentration used in Example 1 for preparing the bioremediation material was replaced with different concentrations. In this example, HCl concentrations of 1 mol / L, 3 mol / L, 5 mol / L, 7 mol / L, and 9 mol / L were selected, with other steps the same as in Example 1 to prepare different bioremediation materials. The results showed that when the HCl concentration was too low (1 mol / L), the reaction rate was too slow, which was detrimental to the subsequent loading process, and the loaded metasilicic acid gel was also uneven. When the HCl concentration was too high (9 mol / L), the reaction rate was too fast, and the generated metasilicic acid gel contained a large amount of unreacted sodium silicate due to mass transfer limitations in the chemical reaction, which was also detrimental to the uniform loading of the metasilicic acid gel. Therefore, this invention determined that when reacting with a sodium silicate solution with a modulus greater than 2.5, an HCl concentration of 3 mol / L-7 mol / L resulted in a suitable reaction rate, and the generated metasilicic acid gel could be more uniformly wetted and loaded onto the polypropylene surface (see...). Figure 11 (HCl concentration is 5 mol / L).

[0083] Example 7: Screening based on the mass ratio of sodium silicate to HCl

[0084] The mass ratio of sodium silicate to HCl in the preparation of bioremediation materials in Example 1 was replaced with other ratios. In this example, the mass ratios of sodium silicate to HCl were 0.5:1, 0.8:1, 1:1 and 1.5:1, respectively. The other steps were the same as in Example 1 to prepare different bioremediation materials. The results showed that when the mass of HCl was greater than the mass of sodium silicate (i.e., 0.5:1 and 0.8:1), the chemical reaction proceeded more completely, with less unreacted sodium silicate, which was more conducive to the uniform loading of the generated metasilicic acid gel on the surface of polypropylene fibers.

[0085] Example 8: Screening of Rhomboid Algae Cell Concentration

[0086] In Example 1, the concentration of *Nyctaginus* cells used to prepare the bioremediation material was replaced with 1×10⁻⁶ cells. 6 cell / mL and 1×10 7 The cell / mL concentration was the same as in Example 1, and other steps were followed to prepare different bioremediation materials; the results showed that the concentration of *Nyctaginosa* cells should be at least 1×10⁻⁶. 7 The order of magnitude is cell / mL (density observed under a microscope using a counting chamber, such as...). Figure 12 The prepared remediation agent can degrade pollutants within 5 days; at a concentration of 1×10⁻⁶ cells in *Nyctaginosa*. 6 The remediation agent prepared at cell / mL needs to degrade the pollutants after 10 days.

[0087] Furthermore, it was found that the cell concentration needed to be greater than 1×10⁻⁶. 7 Only at a cell / mL concentration can *Nyctaginosum* cells completely coat the surface of polypropylene fibers (the condition after this cell concentration coats the polypropylene fibers is as follows). Figure 13 It exhibits a high efficiency in degrading pollutants through the Fenton reaction.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A material for bioremediation of a contaminated water body, characterized by, The biological remediation material for contaminated water body comprises polypropylene fibers, metasilicic acid gel, a reducing iron salt, and nitzschia closterium, wherein the polypropylene fibers are loaded with the metasilicic acid gel on the surface and crosslinked with the reducing iron salt, and the nitzschia closterium is wrapped on the surface of the polypropylene fibers loaded with the metasilicic acid gel and crosslinked with the reducing iron salt; and the preparation method of the biological remediation material for contaminated water body comprises the following steps: (1) soaking polypropylene fibers in a sodium silicate solution, adding a hydrochloric acid solution dropwise, and standing, so that the polypropylene fibers are loaded with metasilicic acid gel on the surface to obtain a remediation material precursor a; (2) soaking the remediation material precursor a in a reducing iron salt solution, so that the reducing iron salt is crosslinked with the metasilicic acid gel to obtain a remediation material precursor b; and (3) soaking the remediation material precursor b in a nitzschia closterium concentrate, so that the nitzschia closterium is wrapped on the surface of the remediation material precursor b to obtain the biological remediation material for contaminated water body; in step (1), the modulus of the sodium silicate is 2.5-3.4; in step (3), the concentration of nitzschia closterium cells in the nitzschia closterium concentrate is ≥1×10 7 cell / ml; in step (1), the mass ratio of sodium silicate to hydrochloric acid is >1:1, and in step (2), the remediation material precursor a is washed with deionized water until the pH of the washing liquid is >7.5, and then soaked in the reducing iron salt solution.

2. The contaminated water body bioremediation material according to claim 1, characterized in that, In step (1), the concentration of the HCl solution is 3 mol / L-7 mol / L; and / or the mass ratio of sodium silicate to HCl is >1:

1.

3. The contaminated water body bioremediation material according to claim 1 or 2, characterized in that, In step (2), the reducing iron salt is one or more of ferrous sulfate, ferrous chloride, ferrous nitrate, ferrous carbonate or ferrous acetate.

4. A device for remediation of a contaminated water body, characterized in that The biological remediation material for the contaminated water body and the carrier as claimed in any one of claims 1 to 3, wherein the biological remediation material for the contaminated water body is arranged on the carrier.

5. The apparatus for restoring a contaminated water body according to claim 4, characterized by The biological remediation material for the contaminated water body is woven into different shapes as a unit, the number of units is ≥2, and the single unit or multiple units are connected in series with intervals on the carrier.

6. The apparatus for restoring a contaminated water body according to claim 4 or 5, characterized by The carrier is a soft strip.

7. The apparatus for restoring a contaminated water body according to claim 6, characterized by The end of the carrier away from the water surface is provided with an anti-floating component.

8. A method of remediating a contaminated water body, characterized by, The biological remediation material for the contaminated water body as claimed in any one of claims 4 to 7 is vertically fixed in the contaminated water body, the number of the biological remediation devices is ≥1, the length of the remediation material on the carrier from the end close to the water surface to the end away from the water surface is ≥0.8 m, and the total projection area of the remediation material accounts for ≥20% of the water surface area. ​

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