Method for preparing biological fermentation heavy metal contaminated soil remediation agent by utilizing phosphogypsum and printing and dyeing sludge, soil remediation agent and application

Abstract

The invention provides a method for preparing a biological fermentation heavy metal contaminated soil remediation agent by utilizing ardealite and printing and dyeing sludge, and belongs to the technical field of solid waste recycling. The method comprises the following steps: mixing printing and dyeing sludge, ironmaking solid waste and ardealite, uniformly stirring, granulating, carrying out aging treatment, carrying out high-temperature pyrolysis, and grinding to obtain phosphorus printing carbonized powder; mixing the cordyceps sobolifera mycelium extract, the pandanus elliottii leaf extract and the red velvet extract, and uniformly stirring to obtain an extraction mixture; beta-nicotinamide mononucleotide and galactomannan are mixed and stirred uniformly, and a probiotic agent is obtained; mixing a probiotic agent, the extraction mixture and food powder, and uniformly stirring to obtain enlightening mixed powder; and mixing the heuristic mixed powder with the phosphorus-printed carbonized powder, uniformly stirring, and adding primary rhizosphere compound bacteria for fermentation, thereby obtaining the biological film covering heavy metal contaminated soil remediation agent after fermentation is finished. The efficient utilization of the phosphogypsum and the printing and dyeing sludge is realized through reasonable proportioning, pyrolysis carbonization and primary rhizosphere compound bacteria synergistic fermentation.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of solid waste resource utilization, and specifically relates to a method for preparing a biological fermentation heavy metal contaminated soil conditioner using phosphogypsum and printing and dyeing sludge, a soil conditioner, and an application thereof. Background Art

[0002] Phosphogypsum, as a by-product in the production of phosphate fertilizer, mainly consists of CaSO4 and contains trace amounts of heavy metals. Printing and dyeing sludge, on the other hand, is a waste generated by the printing and dyeing industry, rich in high organic matter and dye pollutants. Currently, mostly one of these wastes (printing and dyeing sludge or phosphogypsum) is used to form a soil conditioner. For example, using contaminated soil and printing and dyeing sludge as raw materials, combined with other ingredients, and mixing and granulating in a certain proportion to form expanded ceramsite for soil remediation. Another example is the preparation method of a soil conditioner using phosphogypsum as the raw material, which uses plant straw as the main raw material, combined with phosphogypsum and other various biological raw materials to achieve the pollution-free characteristics of the soil conditioner, efficiently condition the soil, improve soil compaction, and quickly repair the soil.

[0003] Currently, there is still a lack of a systematic solution for the composite pollution scenario of phosphogypsum and printing and dyeing sludge. In addition, most of the existing repair agents based on phosphogypsum or printing and dyeing sludge are aimed at single heavy metal or organic pollution. Therefore, it is necessary to propose a method for preparing a soil conditioner by the synergistic action of phosphogypsum and printing and dyeing sludge, which can be used to remove multiple pollutants. Summary of the Invention

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a method for preparing a biological fermentation heavy metal contaminated soil conditioner using phosphogypsum and printing and dyeing sludge, a soil conditioner, and an application thereof.

[0005] In one aspect of the present disclosure, there is provided a method for preparing a biological fermentation heavy metal contaminated soil conditioner using phosphogypsum and printing and dyeing sludge, the method comprising: Mixing printing and dyeing sludge, ironmaking solid waste, and phosphogypsum, stirring evenly, granulating, aging, then performing high-temperature pyrolysis, and pulverizing after the pyrolysis is completed to obtain phospho-print carbonized powder; Mixing cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red quinoa extract, stirring evenly to obtain an extraction mixture; Mixing β-nicotinamide mononucleotide and galactomannan, stirring evenly to obtain a probiotic agent; Mixing the probiotic agent, the extraction mixture, and food powder, stirring evenly to obtain an inspiration mixture powder; Mixing the inspiration mixture powder and the phospho-print carbonized powder, stirring evenly, adding Bergen ball complex bacteria for fermentation, and obtaining a biological film-coated heavy metal contaminated soil conditioner after the fermentation is completed. Optionally, the mass ratio of the printing and dyeing sludge, ironmaking solid waste, and phosphogypsum is (20~60):(5~25):100; and / or, The aging treatment time is 0.5~4.5 days; and / or, The temperature of the high-temperature pyrolysis is 450~950 °C, and the time is 0.5~4.5 hours; and / or, The ironmaking solid waste is any one of blast furnace slag, blast furnace gas sludge, blast furnace gas ash, and sintering dust ash.

[0006] Optionally, the mass ratio of the Cordyceps militaris mycelium extract, Pandanus amaryllifolius leaf extract, and Red Li extract is (0.5~2.5):(2.5~12.5):100.

[0007] Optionally, the mass ratio of β-nicotinamide mononucleotide and galactomannan is (5~25):100.

[0008] Optionally, the mass ratio of the probiotic agent, the extraction mixture, and the food powder is (0.25~1.25):(0.25~2.75):100; and / or, The food powder is any one of wheat flour, oat flour, corn flour, rice flour, kudzu root powder, and lotus root powder.

[0009] Optionally, the mass ratio of the inspiration mixed powder and the phosphorus printing carbonized powder is (5~25):100; and / or, The fermentation time is 5~25 days.

[0010] Optionally, the Bergen ball complex bacteria include rhizobia, Burkholderia, and Glomus.

[0011] Optionally, the rhizobia is any one of Bradyrhizobium elkanii, Rhizobium anhuiense, Rhizobium sphaerophysae, Rhizobium leguminosarum, Bradyrhizobium diazoefficiens, Bradyrhizobium canariense, Rhizobium sophorae, Rhizobium tropici, Rhizobium cellulolyticum, Bradyrhizobium diazotrophicus, Mesorhizobium metallidurans, Mesorhizobium ciceri, Mesorhizobium alhagi, and Rhizobium radiobacter; and / or, The Burkholderia is any one of Burkholderia cepacia, Burkholderia gladioli, Burkholderia stabilis, Paraburkholderia graminis, Burkholderia vietnamiensis, Burkholderia pyrrocinia, Burkholderia multivorans, Paraburkholderia caffeinilytica, Burkholderia andropogonis, Burkholderia ambifaria, Burkholderia nodosa, Burkholderia ulmi, Burkholderia sacchari, and Burkholderia tropica; and / or, The ascospore mold is any one of Streptomyces ascomycin, Anomalomyces caucasicus, Anomalomyces caucasicus var. caucasicus, Anomalomyces altissimus, Anomalomyces niger, Anomalomyces anomalus, Ashbya gossypii, or Endomycopsis fibuligera.

[0012] In another aspect of the present disclosure, a biological fermentation heavy metal contaminated soil remediation agent is provided, which is prepared by the method described above.

[0013] In another aspect of the present disclosure, an application of the biological fermentation heavy metal contaminated soil remediation agent as described above in the remediation of heavy metal contaminated soil is provided.

[0014] The present disclosure provides a method for preparing a biological fermentation heavy metal contaminated soil remediation agent using phosphogypsum and printing and dyeing sludge, a soil remediation agent, and an application. The method includes: mixing printing and dyeing sludge, ironmaking solid waste, and phosphogypsum, stirring evenly, granulating, aging treatment, followed by high-temperature pyrolysis, grinding after pyrolysis to obtain phospho-print carbonized powder; mixing Cordyceps militaris mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract, stirring evenly to obtain an extraction mixture; mixing β-nicotinamide mononucleotide and galactomannan, stirring evenly to obtain a probiotic agent; mixing the probiotic agent, the extraction mixture, and food powder, stirring evenly to obtain an inspiring mixture powder; mixing the inspiring mixture powder and the phospho-print carbonized powder, stirring evenly, adding Bergen ball complex bacteria for fermentation, and obtaining a biological film-covered heavy metal contaminated soil remediation agent after fermentation. The preparation process of the present disclosure is simple. Through reasonable batching, pyrolysis carbonization, and synergistic fermentation of Bergen ball complex bacteria (rhizobia, Burkholderia, and ascospore mold), the efficient utilization of phosphogypsum and printing and dyeing sludge is achieved, and a biological fermentation heavy metal contaminated soil remediation agent is prepared. The prepared remediation agent has a simple usage method, can effectively stabilize heavy metals, and can significantly increase the yield of target vegetation. Description of the Drawings

[0015] Figure 1 It is a flowchart of the method for preparing a biological fermentation heavy metal contaminated soil remediation agent using phosphogypsum and printing and dyeing sludge in the specific embodiment of the present disclosure. Specific Embodiments

[0016] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure, and are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0017] As Figure 1As shown, on one hand, the present disclosure provides a method for preparing a biological fermentation heavy metal contaminated soil remediator using phosphogypsum and printing and dyeing sludge, specifically including the following steps S1 to S5: S1. Mix the printing and dyeing sludge, ironmaking solid waste, and phosphogypsum, stir evenly, granulate, carry out aging treatment, then perform high-temperature pyrolysis, and grind the powder after the pyrolysis ends to obtain phospho-print carbonized powder.

[0018] In some preferred embodiments, the mass ratio of the printing and dyeing sludge, ironmaking solid waste, and phosphogypsum is (20 - 60):(5 - 25):100.

[0019] In some other preferred embodiments, the aging treatment time is 0.5 - 4.5 days.

[0020] In some other preferred embodiments, the high-temperature pyrolysis temperature is 450 - 950 °C, and the time is 0.5 - 4.5 hours.

[0021] In some other preferred embodiments, the ironmaking solid waste is any one of blast furnace slag, blast furnace gas sludge, blast furnace gas ash, and sintering dust ash.

[0022] In step S110, combining the printing and dyeing sludge and phosphogypsum not only solves the technical bottleneck of single solid waste treatment but also realizes the collaborative utilization of resources. The Ca ions in phosphogypsum 2+ have a unique ion exchange ability, which can effectively fix heavy metal ions in the soil and reduce their bioavailability.

[0023] S2. Mix the cordyceps militaris mycelium extract, pandanus odorifer leaf extract, and red li extract, and stir evenly to obtain an extraction mixture.

[0024] In some preferred embodiments, the mass ratio of the cordyceps militaris mycelium extract, pandanus odorifer leaf extract, and red li extract is (0.5 - 2.5):(2.5 - 12.5):100.

[0025] S3. Mix β-nicotinamide mononucleotide and galactomannan, and stir evenly to obtain a probiotic agent.

[0026] In some preferred embodiments, the mass ratio of β-nicotinamide mononucleotide and galactomannan is (5 - 25):100.

[0027] S4. Mix the probiotic agent, the extraction mixture, and food powder, and stir evenly to obtain an inspired mixed powder.

[0028] In some preferred embodiments, the mass ratio of the probiotic agent, the extraction mixture, and food powder is (0.25 - 1.25):(0.25 - 2.75):100.

[0029] In some other preferred embodiments, the food powder is any one of wheat flour, oat flour, corn flour, rice flour, kudzu root powder, and lotus root powder.

[0030] S5. Mix the inspired mixed powder and the phosphorus-printed carbonized powder, stir evenly, add the Bergen ball complex bacteria for fermentation, and obtain a biological film-covered heavy metal-contaminated soil remediator after the fermentation ends. In some preferred embodiments, the mass ratio of the inspired mixed powder to the phosphorus-printed carbonized powder is (5-25):100.

[0031] In some other preferred embodiments, the fermentation time is 5-25 days.

[0032] In some other preferred embodiments, the Bergen ball complex bacteria include rhizobia, Burkholderia, and Glomus.

[0033] As a further preferred option, the rhizobia is any one of Bradyrhizobium elkanii (CGMCC 1.13001), Rhizobium anhuiense (CGMCC 1.15553), Mesorhizobium amorpha (CGMCC 1.11038), Rhizobium leguminosarum (CGMCC 1.11035), Bradyrhizobium yuanmingense (CGMCC 1.15559), Bradyrhizobium canariense (CGMCC 1.15558), Rhizobium sophorae (CGMCC 1.15555), Rhizobium tropici (CGMCC 1.15554), Bradyrhizobium cellulolyticum (CGMCC 1.15995), Bradyrhizobium diazoefficiens (CGMCC 1.15566), Mesorhizobium metallidurans (CGMCC 1.15563), Mesorhizobium ciceri (CGMCC 1.15562), Mesorhizobium wulumuense (CGMCC 1.11022), Rhizobium radiobacter (CGMCC 1.1702).

[0034] As a further preferred embodiment, the Burkholderia is any one of Burkholderia cepacia (CGMCC 1.2787), Burkholderia gladioli (CGMCC 1.5423), Burkholderia stabilis (CGMCC 1.3059), Paraburkholderia graminis (CGMCC 1.7372), Burkholderia vietnamiensis (CGMCC 1.5440), Burkholderia pyrrocinia (CGMCC 1.4964), Burkholderia multivorans (CGMCC 1.3829), Paraburkholderia caffeinilytica (CGMCC 1.15103), Burkholderia andropogonis (CGMCC 1.12338), Burkholderia ambifaria (CGMCC 1.10511), Burkholderia nodosa (CGMCC 1.10205), Burkholderia ulemensis (CGMCC 1.10201), Burkholderia sacchari (CGMCC 1.10200), Burkholderia tropica (CGMCC 1.10195).

[0035] As a further preferred embodiment, the ascospore fungus is any one of Streptomyces ascomycin (CGMCC 4.1388), Apophysomyces elegans var. caucasicus (CGMCC 3.6656), Apophysomyces elegans var. caucasicus (CGMCC 3.6636), Apophysomyces terreus (CGMCC 3.6638), Apophysomyces ater (CGMCC 3.6637), Apophysomyces elegans (CGMCC 3.6654), Ashbya gossypii (CGMCC 2.482), Ashbya gossypii (CGMCC 2.2920).

[0036] In step S150, organic matter in the printing and dyeing sludge will release beneficial substances such as humic acid during the biological fermentation process. These substances can promote the chelation of heavy metals by microorganisms, further enhancing the stabilization of heavy metals. The synergistic effect of the two can form a "calcium-organic matter-microorganism" composite system, which can improve the remediation efficiency in soil remediation.

[0037] Furthermore, the traditional composting fermentation cycle is relatively long, which to a certain extent limits its large-scale application. In response to this, in this embodiment, printing and dyeing sludge, phosphogypsum and microorganisms are used in combination. By adding a specific composite bactericide, the fermentation cycle can be significantly shortened. This multi-strain co-fermentation technology, combined with the alkaline neutralization effect of phosphogypsum, can potentially achieve the simultaneous rapid decomposition of organic matter and stabilization of heavy metals, effectively improving the soil remediation rate. The above-mentioned preparation of a biological fermentation heavy metal contaminated soil remediator using phosphogypsum and printing and dyeing sludge reflects the "treating waste with waste" mode, and can realize the resource-based closed-loop utilization of industrial by-products (phosphogypsum) and municipal solid waste (printing and dyeing sludge), which provides a new path and mode for the development of circular economy. That is to say, the phosphogypsum, printing and dyeing sludge and composite fermentation technology adopted in this embodiment involve the cross-integration of multiple disciplines such as environmental chemistry, microbiology, and materials science. Through the large-scale application of the above cross-technology, the land occupation and pollution risk of these solid wastes can be significantly reduced, bringing positive benefits to the environment.

[0038] It should be noted that the reaction mechanism of the above preparation method in this embodiment is as follows: By mixing the mixed printing and dyeing sludge, iron-making solid waste, and phosphogypsum evenly, granulating, and during the aging process, the components of the printing and dyeing sludge, iron-making solid waste, and phosphogypsum interact with each other. Among them, the organic matter in the printing and dyeing sludge penetrates and adsorbs into the particles of the iron-making solid waste and phosphogypsum. The acidic substances in the phosphogypsum dissolve the metal oxides in the iron-making solid waste and penetrate into the phosphogypsum and printing and dyeing sludge particles and undergo a preliminary chemical precipitation reaction with the phosphate radicals in the phosphogypsum. After the aging is completed, the structure of the overall material becomes more compact and forms a cementitious substance composed of silicates, calcium salts, and iron compounds. In a high-temperature pyrolysis environment, the organic matter adsorbed by the printing and dyeing sludge, iron-making solid waste, and phosphogypsum will undergo a cracking reaction to generate combustible gases, tar-like substances, and carbon residues, which will wrap the metal oxide and gypsum components. The phosphogypsum will first lose its crystal water and transform into CaSO4 and other hydrate forms, and then further undergo a decomposition reaction to produce calcium oxide and sulfur dioxide. Calcium oxide can not only quickly adsorb the pyrolysis products of the organic matter generated by the pyrolysis of the organic matter in the printing and dyeing sludge but also react with the inorganic salts in other materials to form complex composite molten salt complexes. When substances such as the printing and dyeing sludge and iron-making solid waste are pyrolyzed, hydrogen sulfide and ammonia gases will be generated, which will react with the calcium oxide generated by the pyrolysis of the phosphogypsum to form calcium sulfide and calcium amide. The inorganic particles and colloids in the printing and dyeing sludge will generate metal oxides and react with other substances to form complex salts at high temperatures and remain in the solid residue. The iron compounds such as iron oxide in the iron-making solid waste will undergo a reduction reaction on the surface of carbon or tar-like substances in a high-temperature environment to form ferrite substances with a more abundant valence state. Other metal oxides in the iron-making solid waste (such as oxides containing calcium, magnesium, aluminum, etc.) also participate in the exchange reaction between substances and react with the inorganic salts in the phosphogypsum and printing and dyeing sludge to form corresponding composite oxides and composite molten salts. The silicates in the solid waste will undergo physical and chemical changes such as crystal form transformation and recrystallization at high temperatures. During the fermentation process, microorganisms grow and reproduce, and the demand for and utilization rate of nutrients also increase. Rhizobium, Burkholderia, and Glomus will secrete a large amount of extracellular enzymes. Burkholderia secretes protease to decompose protein substrates, decomposing the proteins from the extract into polypeptides and amino acids, which are absorbed by microorganisms for their own protein synthesis. The excess amino acids can be used as substrates for subsequent metabolic reactions and become components for constructing the biological activity of the soil remediation agent. Rhizobium secretes phospholipase and enzymes related to phosphorus metabolism to transform the phosphorus source in the phosphorus-impregnated carbon powder, thereby participating in energy transfer within the microorganisms and providing phosphorus nutrition for plants in the form of available phosphate in the final product of the soil remediation agent. Glomus secretes cellulase to decompose the cellulose component in the red rice extract and provide monosaccharide components such as glucose for microorganisms.On one hand, these monosaccharides can provide energy for microorganisms, which can be converted into the energy in the form of ATP required by themselves through pathways such as glycolysis. On the other hand, monosaccharides such as glucose accumulated in the fermentation medium are also one of the potential effective components for the soil conditioner to enhance biological activities such as the photosynthetic ability of plants. During the fermentation process, some organic acids produced synergistically by complex microorganisms regulate the activity of enzymes, strengthen the enzyme activity, and thus further adjust the metabolic rhythm of the entire fermentation system and the substrate utilization efficiency. Rhizobia secrete amylase and nitrogenase during respiration to decompose the starch in food powder, and produce monosaccharides and a series of nitrogen compounds, providing nitrogen nutrition for plant growth and nutritional components for chlorophyll synthesis. Burkholderia secretes protease and lipase to convert the proteins and fats in the extract and food powder into polypeptides, amino acids, glycerol and fatty acids. Glomus secretes endoglucanase, exoglucanase and β-glucosidase cellulase complex enzymes and hemicellulase, which work together to decompose cellulose and hemicellulose into various monosaccharides and oligosaccharides. During the fermentation process, Rhizobia, Burkholderia and Glomus produce citric acid, succinic acid, etc. through sugar metabolism and continuously produce nitrogen-containing metabolites, such as ammonia (produced by nitrogen fixation of Rhizobia or from ammonification after protein decomposition), amino acids (amino acid metabolites obtained by protein hydrolysis by Burkholderia, etc.). When ammonia meets organic acids, under certain conditions, a reaction occurs. Ammonia and citric acid can react to form ammonium citrate, which is a high-quality nutritional component in the finished soil conditioner, can be absorbed by plants, provide nitrogen and carbon sources, and ammonium citrate also helps to regulate the acid-base balance in plants. Under the influence of specific enzymes produced by microorganisms, some amino acids can be converted into each other through transamination. Alanine and α-ketoglutaric acid can undergo a transamination reaction under the action of alanine aminotransferase. This transamination reaction helps in the synthesis and metabolic regulation of amino acids in microorganisms. In the soil conditioner system, a greater variety of amino acids is beneficial for plants to obtain amino acid nutrition in all aspects, thus promoting the synthesis of related proteins in plants and the improvement of metabolic functions. In the fermentation system, monosaccharides such as glucose obtained by microorganisms decomposing polysaccharides or other carbohydrates react with nitrogen-containing metabolites (amino acids, ammonia, etc.). Under the catalysis of certain enzymes or in a special environment, a glycosylation reaction occurs to form glycoproteins. Such glycoproteins have special biological activities in the soil conditioner system, can adhere better to the surface of plant leaves, slowly release nutritional components, and the glycoprotein structure itself is recognized by plants and serves as a special signal molecule to activate certain defense or growth promotion mechanisms in plants, improving the pest and disease resistance of plants or promoting cell division and growth of plants, etc. Through the decomposition and transformation of various substrates (phosphorus-printed carbonized powder, food powder, various plant extracts, β-nicotinamide mononucleotide, etc.) by microorganisms during the fermentation process, the soil conditioner contains rich nutritional components.Not only can monosaccharides such as glucose obtained from the hydrolysis of polysaccharides provide a rapid energy source for plants and improve the photosynthesis efficiency of plants, but also various amino acids derived from the decomposition of proteins are the basic raw materials for plants to synthesize biological macromolecules such as proteins and enzymes. The presence of nitrogen-containing substances meets the nitrogen nutrition requirements of plants and is crucial for the leaf growth, chlorophyll synthesis, and overall metabolic activities of plants. Moreover, some special nutrients produced during the microbial metabolism process, such as small-molecule organic acids (citric acid, succinic acid, pyruvic acid, malic acid, etc.), contribute to the absorption of other nutrient elements by plants and can also regulate the internal metabolic balance of plants. This diversity of nutrient components meets the requirements of various nutrient elements for different growth stages and different functional needs of plants, and can promote the growth and development of plants more comprehensively compared with single fertilizers. During the fermentation process, in addition to the production of primary metabolites (such as sugars, amino acids, fatty acids, etc.) required for the growth and reproduction of rhizobia, Burkholderia, and Glomus, some secondary metabolites will also be synthesized. Burkholderia produces antibacterial metabolites such as siderophores, phenazines, and pyrrolnitrin. When these antibacterial metabolites are applied to plants as soil remediators, they can reduce the number of pathogenic bacteria on the surface of plant leaves or in the surrounding environment, thereby reducing the risk of plant diseases. Glomus decomposes organic substances in plant extracts to produce some special secondary metabolites, which can protect plants from damage by free radicals and enhance the stress resistance of plants. Through the growth and reproduction of microorganisms, the secretion of enzymes, and numerous reactions among metabolites, the composition of the soil remediator is jointly shaped. The production of various nutrient elements such as monosaccharides, amino acids, and ammonium nitrogen enriches the nutrient pool of the soil remediator, enabling the soil remediator to fully meet the various nutrient requirements for plant growth, from macronutrients such as nitrogen, phosphorus, and potassium to micronutrients. The special bioactive substances produced by microorganisms (such as the antibacterial substances of Burkholderia and the phytohormone analogs of Glomus) cooperate with these nutrients to constitute the multifunctionality of the soil remediator. Rhizobia, Burkholderia, and Glomus have their own metabolic characteristics and advantages in this fermentation system and will also affect each other. The nitrogen fixation of rhizobia provides an available nitrogen source for the system, which is beneficial to the growth of Burkholderia and Glomus. The amino acid and other small peptide molecules produced by the protease secreted by Burkholderia after decomposing proteins are utilized by rhizobia and Glomus in the fermentation system, promoting the material flow and energy transfer between different microorganisms and improving the substrate utilization efficiency of the entire fermentation system.

[0039] On the other hand, the present disclosure proposes a bio-fermented heavy metal contaminated soil remediator, which is prepared by the method described above. For the specific process, please refer to the above description and will not be elaborated here.

[0040] Another aspect of the present disclosure provides an application of a prebiotic fermentation heavy metal contaminated soil remediation agent in the remediation of heavy metal contaminated soil.

[0041] When the soil remediation agent of this embodiment is used for the remediation of heavy metal contaminated soil, it can effectively remove various pollutants such as cadmium and mercury. At the same time, it also helps to improve the metabolic activities of plants, meet the various nutrient element requirements of plants at different growth stages and different functional needs, and thus increase the yield increase rate of lettuce. That is to say, the soil remediation agent of this embodiment can not only remove pollutants such as heavy metals, but also provide nutrients for plants and promote their growth.

[0042] The following will further illustrate the preparation method and specific application of the biological fermentation heavy metal contaminated soil remediation agent in combination with specific examples: It should be noted that the heavy metal contaminated soil and phosphogypsum raw materials used in the following examples are as follows: The heavy metal contaminated soil was prepared by the following method: Weigh 1 kg of uncontaminated soil sample, then add 200 mg of cadmium and 200 mg of mercury to the soil sample, add water to the soil according to the liquid-solid ratio of 1:1 ml / mg, stir evenly, and air-dry naturally after aging for 24 hours to obtain the tested heavy metal contaminated soil sample.

[0043] Phosphogypsum: The phosphogypsum was taken from Guizhou Xifeng Phosphate Mine Co., Ltd. The phosphogypsum sample mainly contains 52.70% SO3, 37.01% CaO, 4.37% SiO2, 2.07% Al2O3, 1.63% P2O5 and other components (inevitable impurities and loss on ignition).

[0044] Example 1 This example illustrates the preparation method by taking the influence of the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum on the performance of the prepared heavy metal contaminated soil remediation agent as an example: Mix printing and dyeing sludge, ironmaking solid waste, and phosphogypsum according to the mass ratios of 12.5:5:100, 15:5:100, 17.5:5:100, 20:2.5:100, 20:3:100, 20:4:100, 20:5:100, 40:5:100, 60:5:100, 20:15:100, 40:15:100, 60:15:100, 20:25:100, 40:25:100, 60:25:100, 60:27.5:100, 60:30:100, 60:32.5:100, 65:25:100, 70:25:100, 75:25:100, stir evenly, granulate, and age for 0.5 days, then carry out high-temperature pyrolysis. After the pyrolysis is completed, grind it into powder to obtain phosphorus-printed carbonized powder. The pyrolysis temperature is 450 °C, the high-temperature pyrolysis time is 0.5 hours, and the ironmaking solid waste is blast furnace slag. Mix Cordyceps militaris mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract according to the mass ratio of 0.5:2.5:100, and stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan according to the mass ratio of 5:100, and stir evenly to obtain a probiotic agent. Mix the probiotic agent, the extraction mixture, and food powder according to the mass ratio of 0.25:0.25:100, and stir evenly to obtain an inspiring mixed powder, where the food powder is wheat flour. Mix the inspiring mixed powder and the phosphorus-printed carbonized powder according to the mass ratio of 5:100, stir evenly, add Bergenia complex bacteria for fermentation, and obtain a heavy metal contaminated soil remediator after the fermentation is completed. The fermentation time is 5 days. The Bergenia complex bacteria are composed of Rhizobium, Burkholderia, and Glomus. The Rhizobium is Rhizobium elaeagnicola (CGMCC 1.13001); the Burkholderia is Burkholderia cepacia (CGMCC 1.2787); the Glomus is Streptomyces ascomycinicus (CGMCC 4.1388).

[0045] Preparation of the remediated heavy metal contaminated soil: Mix the 9 groups of heavy metal contaminated soil remediators prepared in this example with the heavy metal contaminated agricultural land soil according to the mass ratio of 5:100 respectively, stir evenly, sprinkle water evenly, and age for 21 days to obtain 9 groups of remediated heavy metal contaminated agricultural land soil.

[0046] Heavy metal toxicity leaching test: Conduct a toxicity leaching test on the heavy metal contaminated soil samples before and after remediation in accordance with the "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid-Nitric Acid Method" (HJ / T 299-2007).

[0047] Detection of cadmium and mercury ion concentrations: The mercury concentration in the leachate is determined in accordance with the "Water Quality - Determination of Mercury, Arsenic, Selenium, Bismuth, and Antimony - Atomic Fluorescence Spectrometry" (HJ694-2014); the cadmium concentration in the leachate is determined in accordance with the "Water Quality - Determination of 65 Elements - Inductively Coupled Plasma Mass Spectrometry" (HJ700-2014).

[0048] Comparative experiment on lettuce cultivation: Select two identical plots for lettuce cultivation, namely No .1 and No .2 plots. The processes of lettuce seedling selection, planting, and plant protection are the same. During the entire growth cycle No .1 plot does not apply a heavy metal contaminated soil remediator, No .2 plot applies a heavy metal contaminated soil remediator (2 kg per square meter) before transplanting the seedlings. After the planting period ends, harvest the lettuce, wash, dry, and weigh it.

[0049] Lettuce yield increase rate: No The weight difference between the lettuce harvested from plot No .2 and the lettuce harvested from plot No .1 is divided by the weight of the lettuce harvested from plot

[0050] Table 1 Influence of the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum on the performance of the prepared heavy metal contaminated soil remediator

[0051] It can be seen from Table 1 that when the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum is less than 20:5:100 (as shown in Table 1, when the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum = 17.5:5:100, 15:5:100, 12.5:5:100, 20:4:100, 20:3:100, 20:2.5:100 and lower ratios not listed in Table 1), the addition of printing and dyeing sludge and ironmaking solid waste is less, and the reaction of the three materials is insufficient in the subsequent aging and high-temperature pyrolysis environments, resulting in a decline in the performance of the prepared heavy metal contaminated soil remediator. The concentrations of heavy metals cadmium and mercury ions in the remediated soil both increase significantly with the decrease in the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum, and the lettuce yield increase rate decreases significantly with the decrease in the mass ratio of printing and dyeing sludge, ironmaking solid waste, and phosphogypsum.

[0052] Further referring to Table 1, it can be seen that when the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum is equal to 20 - 60:5 - 25:100 (as in Table 1, the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum = 20:5:100, 40:5:100, 60:5:100, 20:15:100, 40:15:100, 60:15:100, 20:25:100, 40:25:100, 60:25:100), the printing and dyeing sludge, iron-making solid waste, and phosphogypsum are mixed, stirred evenly, granulated, and during the aging process, the respective components of the printing and dyeing sludge, iron-making solid waste, and phosphogypsum interact with each other. The organic matter in the printing and dyeing sludge penetrates and adsorbs into the particles of the iron-making solid waste and phosphogypsum. The acidic substances in the phosphogypsum dissolve the metal oxides in the iron-making solid waste, penetrate into the phosphogypsum and printing and dyeing sludge particles, and undergo a preliminary chemical precipitation reaction with the phosphate radicals in the phosphogypsum. After the aging is completed, the structure of the overall material becomes more compact and a cementitious substance composed of silicates, calcium salts, and iron compounds is formed. In a high-temperature pyrolysis environment, the organic matter adsorbed by the printing and dyeing sludge, iron-making solid waste, and phosphogypsum will undergo a cracking reaction, generating combustible gases, tar-like substances, and carbon residues, which wrap the metal oxide and gypsum components. The phosphogypsum will first lose its crystal water and transform into the form of CaSO4 and other hydrates, and then further undergo a decomposition reaction to produce calcium oxide and sulfur dioxide. Calcium oxide can not only quickly adsorb the pyrolysis products of the organic matter generated by the pyrolysis of the organic matter in the printing and dyeing sludge but also react with the inorganic salts in other materials to form complex composite molten salt complexes. When the printing and dyeing sludge, iron-making solid waste, etc. are pyrolyzed, hydrogen sulfide and ammonia gases are generated, which react with the calcium oxide generated by the pyrolysis of the phosphogypsum to form calcium sulfide and calcium amide. The inorganic particles and colloids in the printing and dyeing sludge generate metal oxides and react with other substances to form complex salts at high temperatures and are retained in the solid residue. Iron compounds such as iron oxide in the iron-making solid waste undergo a reduction reaction on the surface of carbon or tar-like substances in a high-temperature environment to form ferrite substances with a more abundant valence state. Other metal oxides in the iron-making solid waste (such as oxides containing calcium, magnesium, aluminum, etc.) also participate in the exchange reaction between substances and react with the inorganic salts in the phosphogypsum and printing and dyeing sludge to form corresponding composite oxides and composite molten salts, and the silicates in the solid waste undergo physical and chemical changes such as crystal form transformation and recrystallization at high temperatures. Finally, the leaching toxicity of cadmium and mercury ions in the soil contaminated with heavy metal pollutants repaired is respectively lower than 0.8 mg / L and 0.6 mg / L, and the lettuce yield increase rate is greater than 116%.

[0053] Further referring to Table 1, it can be seen that when the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum is greater than 60:25:100 (as in Table 1, the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum = 60:27.5:100, 60:30:100, 60:32.5:100, 65:25:100, 70:25:100, 75:25:100 and higher ratios not listed in Table 1), too much printing and dyeing sludge and iron-making solid waste are added, and the material reaction is unbalanced during the high-temperature pyrolysis process, resulting in a decline in the performance of the prepared heavy metal contaminated soil remediator. The leaching concentrations of heavy metals cadmium and mercury in the remediated soil both increase significantly with the further increase of the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum, and the lettuce yield increase rate decreases significantly with the further increase of the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum.

[0054] Therefore, generally speaking, considering the benefits and costs, when the mass ratio of printing and dyeing sludge, iron-making solid waste, and phosphogypsum is equal to 20 - 60:5 - 25:100, it is most beneficial to improve the performance of the prepared heavy metal contaminated soil remediator.

[0055] Example 2 This example illustrates the preparation method by taking the influence of the mass ratio of Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract on the performance of the prepared heavy metal contaminated soil remediator as an example: Mix printing and dyeing sludge, ironmaking solid waste, and phosphogypsum according to a mass ratio of 60:25:100, stir evenly, granulate, and age for 2.5 days. Then, perform high-temperature pyrolysis. After the pyrolysis is completed, grind the powder to obtain phosphorus-printed carbonized powder. The pyrolysis temperature is 700 °C, the high-temperature pyrolysis time is 2.5 hours, and the ironmaking solid waste is blast furnace gas sludge. Mix cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red li extract according to mass ratios of 0.25:2.5:100, 0.3:2.5:100, 0.4:2.5:100, 0.5:1:100, 0.5:1.5:100, 0.5:2:100, 0.5:2.5:100, 1.5:2.5:100, 2.5:2.5:100, 0.5:7.5:100, 1.5:7.5:100, 2.5:7.5:100, 0.5:12.5:100, 1.5:12.5:100, 2.5:12.5:100, 2.5:15:100, 2.5:17.5:100, 2.5:20:100, 3:12.5:100, 3.5:12.5:100, 4:12.5:100, stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan according to a mass ratio of 15:100, stir evenly to obtain a probiotic agent. Mix the probiotic agent, the extraction mixture, and food powder according to a mass ratio of 0.75:1.5:100, stir evenly to obtain an inspiration mixture powder, where the food powder is oatmeal powder. Mix the inspiration mixture powder and the phosphorus-printed carbonized powder according to a mass ratio of 15:100, stir evenly, add the Bergen ball complex bacteria for fermentation, and obtain a biological film-covered heavy metal-contaminated soil repair agent after the fermentation is completed. The fermentation time is 15 days. The Bergen ball complex bacteria are composed of rhizobia, Burkholderia, and Glomus. The rhizobia are Rhizobium anhuiense (CGMCC 1.15553); the Burkholderia is Burkholderia gladioli (CGMCC 1.5423); the Glomus is Glomus aberrans (CGMCC 3.6656).

[0056] The preparation of the heavy metal-contaminated soil after repair, the heavy metal toxicity leaching test, the detection of cadmium and mercury ion concentrations, the lettuce planting comparison test, and the lettuce yield increase rate are the same as in Example 1. The results of this example are shown in Table 2.

[0057] Table 2 Influence of the mass ratio of cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red li extract on the performance of the prepared heavy metal-contaminated soil repair agent

[0058] As can be seen from Table 2, when the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract is less than 0.5:2.5:100 (as in Table 2, the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract = 0.5:2:100, 0.5:1.5:100, 0.5:1:100, 0.4:2.5:100, 0.3:2.5:100, 0.25:2.5:100 and lower ratios not listed in Table 2), the addition of the Cordyceps cicadae mycelium extract and Pandanus amaryllifolius leaf extract is less, and the reaction of the materials is insufficient during the subsequent fermentation process, resulting in a decline in the performance of the heavy metal-contaminated soil remediator. The concentrations of heavy metals cadmium and mercury ions in the remediated soil both increase significantly as the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract decreases, and the lettuce yield increase rate decreases significantly as the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract decreases.

[0059] Further referring to Table 2, it can be seen that when the mass ratio of Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract is equal to 0.5 - 2.5:2.5 - 12.5:100 (as shown in Table 2, when the mass ratio of Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract = 0.5:2.5:100, 1.5:2.5:100, 2.5:2.5:100, 0.5:7.5:100, 1.5:7.5:100, 2.5:7.5:100, 0.5:12.5:100, 1.5:12.5:100, 2.5:12.5:100), during the fermentation process, Burkholderia secretes protease to decompose protein substrates, decomposing the proteins from the extracts into polypeptides and amino acids, which are absorbed by microorganisms for their own protein synthesis. The excess amino acids can serve as substrates for subsequent metabolic reactions and become components for constructing the biological activity of the soil conditioner. Glomus secretes cellulase to decompose the cellulose component in the Bischofia javanica extract, providing monosaccharides such as glucose for microorganisms. Rhizobium secretes amylase and nitrogenase during respiration to decompose the starch in the food powder and produce monosaccharides and a series of nitrogen compounds, providing nitrogen nutrition for plant growth and nutritional components for chlorophyll synthesis. Burkholderia secretes protease and lipase to convert the proteins and fats in the extracts and food powder into polypeptides, amino acids, glycerol, and fatty acids. Glomus secretes endoglucanase, exoglucanase, β-glucanase cellulase complex enzyme, and hemicellulase, which synergistically decompose cellulose and hemicellulose into various monosaccharides and oligosaccharides. Through the decomposition and transformation of various substrates by microorganisms during the fermentation process, the soil conditioner contains rich nutritional components. Glomus decomposes the organic matter in the plant extract to produce some special secondary metabolites, which can protect plants from the damage of free radicals and enhance the stress resistance of plants. Finally, the leaching toxicity of cadmium and mercury ions in the soil contaminated with heavy metals repaired is respectively lower than 0.4 mg / L and 0.3 mg / L, and the yield increase rate of lettuce is greater than 133%.

[0060] Further referring to Table 2, it can be seen that when the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and red Li extract is greater than 2.5:12.5:100 (as shown in Table 2, the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and red Li extract = 2.5:15:100, 2.5:17.5:100, 2.5:20:100, 3:12.5:100, 3.5:12.5:100, 4:12.5:100 and higher ratios not listed in Table 2), too much Cordyceps cicadae mycelium extract and Pandanus amaryllifolius leaf extract are added, and the material reaction during fermentation is unbalanced, resulting in a decline in the performance of the prepared heavy metal contaminated soil remediator. The leaching concentrations of heavy metals cadmium and mercury in the remediated soil both increase significantly as the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and red Li extract further increases, and the lettuce yield increase rate decreases significantly as the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and red Li extract further increases.

[0061] Therefore, generally speaking, considering the benefits and costs, when the mass ratio of the Cordyceps cicadae mycelium extract, Pandanus amaryllifolius leaf extract, and red Li extract is equal to 0.5~2.5:2.5~12.5:100, it is most beneficial to improve the performance of the prepared heavy metal contaminated soil remediator.

[0062] Example 3 This example illustrates the preparation method by taking the influence of the mass ratio of the probiotic agent, extraction mixture, and food powder on the performance of the prepared heavy metal contaminated soil remediator as an example: Mix printing and dyeing sludge, ironmaking solid waste, and phosphogypsum in a mass ratio of 60:25:100, stir evenly, granulate, and age for 4.5 days. Then, perform high-temperature pyrolysis. After the pyrolysis is completed, grind the product to obtain phosphorus-printed carbonized powder. The pyrolysis temperature is 950 °C, the high-temperature pyrolysis time is 4.5 hours, and the ironmaking solid waste is blast furnace gas ash. Mix cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red li extract in a mass ratio of 2.5:12.5:100, stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan in a mass ratio of 25:100, stir evenly to obtain a probiotic agent. Mix the probiotic agent, extraction mixture, and food powder in mass ratios of 0.1:0.25:100, 0.15:0.25:100, 0.2:0.25:100, 0.25:0.1:100, 0.25:0.15:100, 0.25:0.2:100, 0.25:0.25:100, 0.75:0.25:100, 1.25:0.25:100, 0.25:1.5:100, 0.75:1.5:100, 1.25:1.5:100, 0.25:2.75:100, 0.75:2.75:100, 1.25:2.75:100, 1.25:3:100, 1.25:3.25:100, 1.25:3.5:100, 1.5:2.75:100, 1.75:2.75:100, 2:2.75:100, stir evenly to obtain an inspiring mixture powder, where the food powder is corn flour. Mix the inspiring mixture powder and phosphorus-printed carbonized powder in a mass ratio of 25:100, stir evenly, add Bergen ball complex bacteria for fermentation. After the fermentation is completed, obtain a biological film-covered heavy metal contaminated soil remediator. The fermentation time is 25 days. The Bergen ball complex bacteria are composed of rhizobia, Burkholderia, and Glomus. The rhizobia are Mesorhizobium amorpha (CGMCC 1.11038); the Burkholderia is Burkholderia stabilis (CGMCC 1.3059); the Glomus is Glomus aberrans var. caucasicum (CGMCC 3.6636).

[0063] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the detection of cadmium and mercury ion concentrations, the lettuce planting comparison test, and the lettuce yield increase rate are the same as in Example 1. The results of this example are shown in Table 3.

[0064] Table 3 Influence of the mass ratio of the probiotic agent, extraction mixture, and food powder on the performance of the prepared heavy metal contaminated soil remediator

[0065] As can be seen from Table 3, when the mass ratio of the probiotic agent, the extraction mixture, and the food powder is less than 0.25:0.25:100 (as in Table 3, the mass ratio of the probiotic agent, the extraction mixture, and the food powder = 0.25:0.2:100, 0.25:0.15:100, 0.25:0.1:100, 0.2:0.25:100, 0.15:0.25:100, 0.1:0.25:100 and lower ratios not listed in Table 3), the addition of the probiotic agent and the extraction mixture is less, and the material reaction is insufficient during the subsequent fermentation process, resulting in a decline in the performance of the heavy metal contaminated soil remediator prepared. The concentrations of heavy metals cadmium and mercury ions in the remediated soil both increase significantly with the decrease of the mass ratio of the probiotic agent, the extraction mixture, and the food powder, and the lettuce yield increase rate decreases significantly with the decrease of the mass ratio of the probiotic agent, the extraction mixture, and the food powder.

[0066] Further referring to Table 3, it can be seen that when the mass ratio of the probiotic agent, the extraction mixture, and the food powder is equal to 0.25 - 1.25:0.25 - 2.75:100 (as shown in Table 3, when the mass ratio of the probiotic agent, the extraction mixture, and the food powder = 0.25:0.25:100, 0.75:0.25:100, 1.25:0.25:100, 0.25:1.5:100, 0.75:1.5:100, 1.25:1.5:100, 0.25:2.75:100, 0.75:2.75:100, 1.25:2.75:100), during the fermentation process, some organic acids produced synergistically by the complex microorganisms regulate the activity of enzymes, strengthen the enzyme activity, and thus further adjust the metabolic rhythm and substrate utilization efficiency of the entire fermentation system. Rhizobia secrete amylase and nitrogenase during respiration to decompose the starch in the food powder and produce monosaccharides and a series of nitrogen compounds, providing nitrogen nutrition for plant growth and nutritional components for chlorophyll synthesis. Burkholderia secretes protease and lipase to convert the proteins and fats in the extract and food powder into polypeptides, amino acids, glycerol, and fatty acids. Glomus secretes endoglucanase, exoglucanase, and β-glucosidase cellulase complex enzymes and hemicellulase, which work together to decompose cellulose and hemicellulose into various monosaccharides and oligosaccharides. When ammonia meets an organic acid, a reaction occurs under certain conditions. Ammonia and citric acid can react to form ammonium citrate, which is a high-quality nutritional component in the finished soil conditioner and can be absorbed by plants to provide nitrogen and carbon sources. Under the influence of specific enzymes produced by microorganisms, some amino acids can be interconverted through transamination. Alanine and α-ketoglutaric acid can undergo a transamination reaction under the action of glutamic-pyruvic transaminase. This transamination reaction is helpful for the synthesis and metabolic regulation of amino acids in microorganisms. In the soil conditioner system, a greater variety of amino acids is beneficial for plants to obtain amino acid nutrition comprehensively, thus promoting the synthesis of related proteins in plants and the improvement of metabolic functions. In the fermentation system, monosaccharides such as glucose obtained by microorganisms decomposing polysaccharides or other carbohydrates react with nitrogen-containing metabolites (amino acids, ammonia, etc.) to undergo a condensation reaction, and under the catalysis of certain enzymes or in a special environment, a glycosylation reaction occurs to form glycoproteins. Through the decomposition and transformation of various substrates (phosphorus-imprinted carbonized powder, food powder, various plant extracts, β-nicotinamide mononucleotide, etc.) by microorganisms during the fermentation process, the soil conditioner contains rich nutritional components. Not only do monosaccharides such as glucose obtained by polysaccharide hydrolysis provide a rapid energy source for plants and improve the photosynthesis efficiency of plants, but also various amino acids decomposed from proteins are the basic raw materials for plants to synthesize biological macromolecules such as proteins and enzymes. In addition to the production of primary metabolites (such as sugars, amino acids, fatty acids, etc.) required for the growth and reproduction of Rhizobia, Burkholderia, and Glomus, some secondary metabolites will also be synthesized. Burkholderia produces antibacterial active metabolites such as siderophores, phenazines, and pyrrolnitrin.These antibacterial metabolites can reduce the number of pathogenic bacteria on the surface of plant leaves or in the surrounding environment when the soil conditioner is applied to plants, thereby reducing the risk of plant diseases. Vesicular-arbuscular mycorrhizal fungi decompose organic matter in plant extracts to produce some special secondary metabolites, which can protect plants from the damage of free radicals and enhance the stress resistance of plants. Through the growth and reproduction of microorganisms, the secretion of enzymes, and numerous reactions among metabolites, the composition of the soil conditioner is jointly shaped. The special bioactive substances produced by microorganisms (such as antibacterial substances of Burkholderia and phytohormone analogs of vesicular-arbuscular mycorrhizal fungi) synergize with these nutrients to constitute the multifunctionality of the soil conditioner. Rhizobium, Burkholderia, and vesicular-arbuscular mycorrhizal fungi have their own metabolic characteristics and advantages in this fermentation system and will also affect each other. The nitrogen fixation of Rhizobium provides available nitrogen sources for the system, which is beneficial to the growth of Burkholderia and vesicular-arbuscular mycorrhizal fungi. The small peptide molecules such as amino acids produced after the protease secreted by Burkholderia decomposes proteins are utilized by Rhizobium and vesicular-arbuscular mycorrhizal fungi in the fermentation system, promoting the material flow and energy transfer between different microorganisms and improving the substrate utilization efficiency of the entire fermentation system. Finally, the leaching toxicity of cadmium and mercury ions in the soil contaminated with heavy metals repaired is respectively lower than 0.1 mg / L and 0.1 mg / L, and the yield increase rate of lettuce is greater than 150%.

[0067] Further referring to Table 3, it can be seen that when the mass ratio of the probiotic agent, extraction mixture, and food powder is greater than 1.25:2.75:100 (as in Table 3, the mass ratio of the probiotic agent, extraction mixture, and food powder = 1.25:3:100, 1.25:3.25:100, 1.25:3.5:100, 1.5:2.75:100, 1.75:2.75:100, 2:2.75:100 and higher ratios not listed in Table 3), too much of the probiotic agent and extraction mixture are added, and the material reaction in the fermentation process is unbalanced, resulting in a decline in the performance of the prepared heavy metal contaminated soil conditioner. The leaching concentrations of heavy metals cadmium and mercury in the repaired soil increase significantly with the further increase of the mass ratio of the probiotic agent, extraction mixture, and food powder, and the yield increase rate of lettuce decreases significantly with the further increase of the mass ratio of the probiotic agent, extraction mixture, and food powder.

[0068] Therefore, generally speaking, considering the benefits and costs, when the mass ratio of the probiotic agent, extraction mixture, and food powder is equal to 0.25~1.25:0.25~2.75:100, it is most beneficial to improve the performance of the prepared heavy metal contaminated soil conditioner.

[0069] Example 4 This example illustrates the preparation method by taking the influence of Rhizobium on the performance of the prepared heavy metal contaminated soil conditioner as an example: Mix printing and dyeing sludge, iron-making solid waste, and phosphogypsum in a mass ratio of 60:25:100, stir evenly, granulate, and age for 4.5 days. Then, perform high-temperature pyrolysis. After the pyrolysis is completed, grind the product to obtain phospho-printed carbonized powder. The pyrolysis temperature is 950 °C, the high-temperature pyrolysis time is 4.5 hours, and the iron-making solid waste is sintering flue dust ash. Mix cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red li extract in a mass ratio of 2.5:12.5:100, and stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan in a mass ratio of 25:100, and stir evenly to obtain a probiotic agent. Mix the probiotic agent, the extraction mixture, and food powder in a mass ratio of 1.25:2.75:100, and stir evenly to obtain an inspiring mixture powder, where the food powder is rice flour. Mix the inspiring mixture powder and the phospho-printed carbonized powder in a mass ratio of 15:100, stir evenly, add the Bergen ball complex bacteria for fermentation, and obtain a biological film-coated heavy metal contaminated soil remediator after the fermentation is completed. The fermentation time is 25 days. The Bergen ball complex bacteria are composed of rhizobia, Burkholderia, and Glomus. The rhizobia are any one of Bradyrhizobium erythrophlei (CGMCC 1.13001), Bradyrhizobium anhuiense (CGMCC1.15553), Bradyrhizobium sphaerophysae (CGMCC 1.11038), Rhizobium leguminosarum (CGMCC 1.11035), Bradyrhizobium elkanii (CGMCC 1.15559), Bradyrhizobium canariense (CGMCC 1.15558), Bradyrhizobium sophorae (CGMCC1.15555), Rhizobium tropici (CGMCC 1.15554), Bradyrhizobium cellulolyticum (CGMCC 1.15995), Bradyrhizobium diazoefficiens (CGMCC 1.15566), Mesorhizobium metallidurans (CGMCC 1.15563), Mesorhizobium ciceri (CGMCC1.15562), Mesorhizobium wulianense (CGMCC 1.11022), Rhizobium radiobacter (CGMCC 1.1702); the Burkholderia is Paraburkholderia graminis (CGMCC 1.7372); the Glomus is Glomus maximus (CGMCC3.6638).

[0070] The preparation of the heavy metal contaminated soil after remediation, the heavy metal toxicity leaching test, the detection of cadmium and mercury ion concentrations, the lettuce planting comparison test, and the lettuce yield increase rate are the same as in Example 1. The results of this example are shown in Table 4.

[0071] Table 4 Influence of rhizobia on the performance of the prepared heavy metal contaminated soil remediator

[0072] As can be seen from Table 4, when the rhizobia are any one of Bradyrhizobium elkanii, Rhizobium anhuiense, Mesorhizobium amorpha, Rhizobium leguminosarum, Bradyrhizobium yuanmingense, Bradyrhizobium canariense, Rhizobium sophorae, Rhizobium tropici, Cellulomonas rhizobia, Bradyrhizobium diazoefficiens, Mesorhizobium metallidurans, Mesorhizobium ciceri, Mesorhizobium alhagi, Rhizobium radiobacter, there is no significant difference in the heavy metal leaching concentration and the lettuce yield increase rate achieved.

[0073] Example 5 This example illustrates the preparation method by taking the effect of Burkholderia on the performance of the prepared heavy metal contaminated soil remediator as an example: Mix printing and dyeing sludge, iron-making solid waste, and phosphogypsum in a mass ratio of 60:25:100, stir evenly, granulate, and age for 4.5 days. Then, perform high-temperature pyrolysis. After the pyrolysis is completed, grind the product to obtain phosphorus-printed carbonized powder. The pyrolysis temperature is 950 °C, the high-temperature pyrolysis time is 2.5 hours, and the iron-making solid waste is sintered flue dust ash. Mix cordyceps militaris mycelium extract, pandanus amaryllifolius leaf extract, and red li extract in a mass ratio of 2.5:12.5:100, and stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan in a mass ratio of 25:100, and stir evenly to obtain a probiotic agent. Mix the probiotic agent, the extraction mixture, and food powder in a mass ratio of 1.25:2.75:100, and stir evenly to obtain an inspiration mixture powder, where the food powder is kudzu root powder. Mix the inspiration mixture powder and the phosphorus-printed carbonized powder in a mass ratio of 25:100, stir evenly, add Bergen ball complex bacteria for fermentation, and obtain a biological film-covered heavy metal-contaminated soil repair agent after the fermentation is completed. The fermentation time is 25 days. The Bergen ball complex bacteria are composed of rhizobia, Burkholderia, and Glomus. The rhizobia is Rhizobium radiobacter (CGMCC 1.1702); the Burkholderia is Burkholderia cepacia (CGMCC 1.2787), Burkholderia gladioli (CGMCC 1.5423), Burkholderia stabilis (CGMCC 1.3059), Paraburkholderia graminis (CGMCC 1.7372), Burkholderia vietnamiensis (CGMCC 1.5440), Burkholderia pyrrocinia (CGMCC 1.4964), Burkholderia multivorans (CGMCC1.3829), Paraburkholderia caffeinilytica (CGMCC 1.15103), Burkholderia andropogonis (CGMCC1.12338), Burkholderia ambifaria (CGMCC 1.10511), Burkholderia nodosa (CGMCC 1.10205), Burkholderia ulramarina (CGMCC 1.10201), Burkholderia sacchari (CGMCC 1.10200), Burkholderia tropica (CGMCC 1.10195); the Glomus is Glomus melanosporum (CGMCC 3.6637).

[0074] The preparation of the repaired heavy metal-contaminated soil, the heavy metal toxicity leaching test, the detection of cadmium and mercury ion concentrations, the lettuce planting comparison test, and the lettuce yield increase rate are the same as in Example 1. The results of this example are shown in Table 5.

[0075] Table 5 Influence of Burkholderia on the performance of the prepared heavy metal-contaminated soil repair agent

[0076] As can be seen from Table 5, when the Burkholderia is any one of Burkholderia cepacia, Burkholderia gladioli, Burkholderia stabilis, Paraburkholderia graminis, Burkholderia vietnamiensis, Burkholderia pyrrocinia, Burkholderia multivorans, Paraburkholderia caffeinilytica, Burkholderia andropogonis, Burkholderia ambifaria, Burkholderia nodosa, Burkholderia ulamensis, Burkholderia sacchari, Burkholderia tropica, there is no significant difference in the heavy metal leaching concentration and the lettuce yield increase rate achieved.

[0077] Example 6 This example illustrates the preparation method by taking the influence of Burkholderia on the performance of the prepared heavy metal contaminated soil remediator as an example: Mix printing and dyeing sludge, ironmaking solid waste, and phosphogypsum according to a mass ratio of 40:15:100, stir evenly, granulate, and age for 2.5 days, then carry out high-temperature pyrolysis. After the pyrolysis is completed, grind it into powder to obtain phospho-printed carbonized powder, where the pyrolysis temperature is 950 °C and the high-temperature pyrolysis time is 4.5 hours, and the ironmaking solid waste is blast furnace gas sludge. Mix Cordyceps militaris mycelium extract, Pandanus amaryllifolius leaf extract, and Red Li extract according to a mass ratio of 2.5:12.5:100, and stir evenly to obtain an extraction mixture. Mix β-nicotinamide mononucleotide and galactomannan according to a mass ratio of 25:100, and stir evenly to obtain a probiotic agent. Mix the probiotic agent, the extraction mixture, and food powder according to a mass ratio of 1.25:2.75:100, and stir evenly to obtain an inspiring mixed powder, where the food powder is lotus root starch. Mix the inspiring mixed powder and the phospho-printed carbonized powder according to a mass ratio of 25:100, stir evenly, add Bergen ball complex bacteria for fermentation, and after the fermentation is completed, obtain a biological film-coated heavy metal contaminated soil remediator, where the fermentation time is 25 days, and the Bergen ball complex bacteria is composed of rhizobia, Burkholderia, and vesicular mycorrhizae. The rhizobia is Mesorhizobium alhagi (CGMCC 1.11022); the Burkholderia is Burkholderia tropica (CGMCC 1.10195); the vesicular mycorrhizae is any one of Streptomyces ascomycin (CGMCC 4.1388), Abascus abnormis (CGMCC 3.6656), Abascus abnormis var. caucasicus (CGMCC 3.6636), Abascus altissimus (CGMCC3.6638), Abascus niger (CGMCC 3.6637), Abascus abnormis (CGMCC 3.6654), Ascochyta gossypii (CGMCC2.482), Ascochyta gossypii (CGMCC 2.2920).

[0078] The preparation of the heavy metal contaminated soil after remediation, the heavy metal toxicity leaching test, the detection of cadmium and mercury ion concentrations, the lettuce planting comparison test, and the lettuce yield increase rate are the same as in Example 1. The results of this example are shown in Table 6.

[0079] Table 6 Influence of Ascosporic Fungi on the Performance of the Prepared Heavy Metal Contaminated Soil Remediation Agent

[0080] As can be seen from Table 6, when the ascosporic fungi is any one of Streptomyces ascomycin, Abnormalyomyces caucasicus, Abnormalyomyces caucasicus var. caucasicus, Abnormalyomyces extremus, Abnormalyomyces ater, Abnormalyomyces anomalus, Ashbya gossypii, there is no significant difference in the heavy metal leaching concentration and the lettuce yield increase rate achieved.

[0081] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present disclosure. However, the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A method for preparing a biological fermentation heavy metal contaminated soil remediator using phosphogypsum and printing and dyeing sludge, characterized in that, The method includes: Mixing printing and dyeing sludge, ironmaking solid waste, and phosphogypsum, stirring evenly, granulating, aging, followed by high-temperature pyrolysis, and pulverizing after pyrolysis to obtain phospho-printed carbonized powder; Mixing Cordyceps militaris mycelium extract, Pandanus amaryllifolius leaf extract, and Bischofia javanica extract, and stirring evenly to obtain an extraction mixture; Mixing β-nicotinamide mononucleotide and galactomannan, and stirring evenly to obtain a probiotic agent; Mixing the probiotic agent, the extraction mixture, and food powder, and stirring evenly to obtain an inspiring mixed powder; Mixing the inspiring mixed powder and the phospho-printed carbonized powder, stirring evenly, adding Bergen ball complex bacteria for fermentation, and obtaining a biological film-covered heavy metal contaminated soil remediator after fermentation.

2. The method according to claim 1, characterized in that The mass ratio of the printing and dyeing sludge, the ironmaking solid waste, and the phosphogypsum is (20~60):(5~25):100; and / or, The aging time is 0.5~4.5 days; and / or, The temperature of the high-temperature pyrolysis is 450~950 °C, and the time is 0.5~4.5 hours; and / or, The ironmaking solid waste is any one of blast furnace slag, blast furnace gas sludge, blast furnace gas ash, and sintering dust ash.

3. The method according to claim 1, wherein The mass ratio of the Cordyceps militaris mycelium extract, the Pandanus amaryllifolius leaf extract, and the Bischofia javanica extract is (0.5~2.5):(2.5~12.5):

100.

4. The method according to claim 1, characterized in that, The mass ratio of the β-nicotinamide mononucleotide and the galactomannan is (5~25):

100.

5. The method according to claim 1, wherein The mass ratio of the probiotic agent, the extraction mixture, and the food powder is (0.25~1.25):(0.25~2.75):100; and / or, The food powder is any one of wheat flour, oat flour, corn flour, rice flour, kudzu root powder, and lotus root powder.

6. The method according to claim 1, wherein The mass ratio of the inspiring mixed powder and the phospho-printed carbonized powder is (5~25):100; and / or, The fermentation time is 5~25 days.

7. The method according to claim 1, wherein The Bergen ball complex bacteria include rhizobia, Burkholderia, and Glomus.

8. The method according to claim 7, characterized in that, The rhizobia are any one of Bradyrhizobium erythrophlei, Bradyrhizobium anhuiense, Bradyrhizobium sp. hedysari, Rhizobium leguminosarum, Bradyrhizobium elkanii, Bradyrhizobium canariense, Bradyrhizobium robiniae, Bradyrhizobium tropici, Bradyrhizobium cellulolyticum, Bradyrhizobium diazoefficiens, Bradyrhizobium metallireducens, Bradyrhizobium ciceri, Bradyrhizobium sp. wulumuense, Bradyrhizobium radiobacter; and / or, The Burkholderia are any one of Burkholderia cepacia, Burkholderia gladioli, Burkholderia stabilis, Paraburkholderia graminis, Burkholderia vietnamiensis, Burkholderia pyrrocinia, Burkholderia multivorans, Paraburkholderia caffeinilytica, Burkholderia andropogonis, Burkholderia ambifaria, Burkholderia nodosa, Burkholderia ulmi, Burkholderia sacchari, Burkholderia tropica; and / or, The Glomus are any one of Streptomyces ascomycin, Embellisia caucasica, Embellisia caucasica var. caucasica, Embellisia altissima, Embellisia nigrans, Embellisia sp., Achlya polyandra, Ashbya gossypii.

9. A biological fermentation heavy metal contaminated soil remediator, characterized in that, The biological fermentation heavy metal contaminated soil remediator is prepared by the method described in any one of claims 1 to 8.

10. Application of a biological fermentation heavy metal contaminated soil remediator as described in claim 9 in the remediation of heavy metal contaminated soil.

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