Method for preparing heavy metal contaminated soil remediation agent from ardealite and sulfur residues, soil remediation agent and application

Abstract

The invention provides a method for preparing a heavy metal contaminated soil remediation agent from ardealite and sulfur residues, the soil remediation agent and application, and belongs to resource utilization of industrial solid waste. The method comprises the following steps: mixing sulfur slag, fly ash and ardealite, uniformly stirring, and aging to obtain a sulfur and coal ash mixed gypsum material; mixing the apple concentrated juice, the mulberry primary pulp and the raspberry primary pulp, and uniformly stirring to obtain an activated mixture; mixing the activated mixture, the straw powder and the sulfur coal ash with the gypsum material, and uniformly stirring to obtain a mixed to-be-fermented material; and sulfur-nitrogen chain mixed bacteria are added into the mixed to-be-fermented material for fermentation treatment, and the heavy metal contaminated soil remediation agent is obtained. The preparation process is simple, full resource utilization of the coagulated gypsum and the sulfur residues is achieved through reasonable matching of materials and a flora structure, the heavy metal contaminated soil stabilizer prepared through synergistic fermentation of mixed bacteria is remarkable in performance, the leaching concentration of heavy metal can be remarkably reduced, and the yield of planted lettuce can be remarkably increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource utilization of industrial solid wastes, and specifically relates to a method for preparing a heavy metal contaminated soil remediation agent by utilizing phosphogypsum and sulfur slag, a soil remediation agent and an application thereof. Background Art

[0002] With the rapid development of modern agriculture, industry and transportation, a variety of heavy metals have accumulated in the ecological environment, causing damage to soil biodiversity, exacerbating the destruction of resources and threatening the safety and health of organisms. Excessive concentrations of heavy metals will not only affect crop growth, but will also accumulate through the food chain and ultimately endanger human health.

[0003] Therefore, it is necessary to remediate heavy metal contaminated soil. The current stabilization remediation of heavy metal contaminated soil refers to adding an appropriate amount of targeted heavy metal stabilization agents to the contaminated soil. Through a series of reactions such as adsorption, precipitation, complexation, ion exchange and oxidation-reduction between the agents and the soil heavy metal pollutants, the existence form of heavy metal pollutants in the soil is changed in physical, chemical or physicochemical forms, reducing the toxicity, solubility, mobility and bioavailability of heavy metal pollutants, thereby reducing health risks and achieving remediation effects. Therefore, heavy metal contaminated soil remediation agents are crucial.

[0004] The current relevant literature provides phosphogypsum as a base material as a soil conditioner. As a major by-product of the phosphorus chemical industry, phosphogypsum has a complex composition but is rich in calcium sulfate and a variety of trace elements. It can effectively alleviate mercury pollution in the soil, but its removal effect is general. In addition to phosphogypsum, it also needs to be compounded with a variety of other reagents, which is costly. Summary of the invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag, a soil remediation agent and applications.

[0006] In one aspect of the present disclosure, there is provided a method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag, the method comprising: The sulfur slag, fly ash and phosphogypsum are mixed, stirred evenly, and aged to obtain a sulfur fly ash mixed gypsum material; Mix apple juice concentrate, mulberry puree and raspberry puree, stir evenly to obtain an activated mixture; The activated mixture, straw powder, and the sulfur-fuel ash mixed with gypsum material are mixed and stirred evenly to obtain a mixed material to be fermented; Add sulfur-nitrogen chain mixed bacteria to the mixed material to be fermented for fermentation to obtain a heavy metal contaminated soil repair agent.

[0007] Optionally, the mass ratio of the sulfur slag, the fly ash and the phosphogypsum is (5-25):(20-60):100.

[0008] Optionally, the aging treatment time is 6 to 24.

[0009] Optionally, the mass ratio of the apple juice concentrate, the mulberry puree and the raspberry puree is (5-25):(20-60):100.

[0010] Optionally, the mass ratio of the activated mixture, the straw powder, and the sulfur-fuel ash mixed with the gypsum material is (1.5~7.5):(5~25):100.

[0011] Optionally, the fermentation treatment time is 5 to 25 days, and the fermentation treatment temperature is 15 to 55°C.

[0012] Optionally, the sulfur-nitrogen chain mixed bacteria include desulfurization bacteria, nitrogen-fixing bacteria, and Streptomyces.

[0013] Optionally, the desulfurizing bacteria is any one of Desulfovibrio vulgaris, Xiamen Desulfovibrio bacillus, Norwegian Desulfovibrio, Escambia River Desulfovibrio, Maestral Desulfovibrio, Rumen Desulfovibrio, Desulfovibrio desulfuricans, Desulfovibrio fructovora, rod-shaped Desulfovibrio, and Desulfovibrio gordonella; and / or, The nitrogen-fixing bacteria is any one of Azospirillum brasiliensis, Azotobacter beijerii, Rhodobacter azotobacter, Azotobacter armeniaca, Azotobacter fusca, Azotobacter iraqia, Azotobacter vinelandii, Azotobacter fusca, and Azotobacter active; and / or, The streptomyces is any one of olive-chromogenic Streptomyces, Wedmore Streptomyces, Malaysian Streptomyces, fine yellow Streptomyces, nail-spotted Streptomyces, Louche Streptomyces, litmus-killing Streptomyces, golden Streptomyces, blackened Streptomyces, grass-colored Streptomyces, light purple gray Streptomyces, sky blue yellow Streptomyces, dark heterowalled Streptomyces, grassy Streptomyces, gray wheel silk Streptomyces, straight wheel silk Streptomyces, Hiroshima Streptomyces, thermo-common Streptomyces, thermophilic alkali-resistant Streptomyces, thermophilic feces-loving Streptomyces, olive Streptomyces, litmus-killing Streptomyces, and micro Streptomyces.

[0014] Another aspect of the present disclosure provides a heavy metal contaminated soil remediation agent, which is prepared by the method described above.

[0015] Another aspect of the present disclosure provides a use of the heavy metal contaminated soil remediation agent as described above in the remediation of heavy metal contaminated soil.

[0016] The present disclosure provides a method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag, a soil remediation agent and application. The method comprises: mixing sulfur slag, fly ash and phosphogypsum, stirring evenly, and aging to obtain a sulfur-coal ash mixed gypsum material; mixing apple juice concentrate, mulberry puree and raspberry puree, stirring evenly to obtain an activated mixture; mixing the activated mixture, straw powder and the sulfur-coal ash mixed gypsum material, stirring evenly to obtain a mixed fermentation material; adding sulfur-nitrogen chain mixed bacteria to the mixed fermentation material for fermentation treatment to obtain a heavy metal contaminated soil remediation agent. The preparation process disclosed in the present disclosure is simple. By reasonably matching materials and bacterial community structures, full resource utilization of gypsum and sulfur slag is achieved. The heavy metal contaminated soil stabilizer prepared by the synergistic fermentation of desulfurization bacteria, nitrogen-fixing bacteria and streptomyces has significant performance, which can significantly reduce the concentration of heavy metal leaching and significantly increase the yield of the planted lettuce. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of a method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. 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 ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0019] As shown in FIG1 , one aspect of the present disclosure provides a method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag, which specifically includes the following steps S1 to S4: S1. Mix sulfur slag, fly ash and phosphogypsum, stir evenly, and age to obtain sulfur fly ash mixed gypsum material.

[0020] In some preferred embodiments, the mass ratio of sulfur slag, fly ash and phosphogypsum is (5-25):(20-60):100. In other preferred embodiments, the aging time is 6 to 24 hours.

[0021] S2. Mix the apple juice concentrate, mulberry puree and raspberry puree, and stir evenly to obtain an activated mixture.

[0022] In some preferred embodiments, the mass ratio of apple juice concentrate, mulberry puree and raspberry puree is (5-25):(20-60):100.

[0023] S3, mixing the activated mixture, the straw powder, the sulfur-fuel ash and the gypsum material, stirring evenly to obtain a mixed material to be fermented.

[0024] In some preferred embodiments, the mass ratio of the activated admixture, the straw powder, and the sulfur-fuel ash mixed with the gypsum material is (1.5~7.5):(5~25):100.

[0025] S4. Add sulfur-nitrogen chain mixed bacteria to the mixed material to be fermented for fermentation to obtain a heavy metal contaminated soil remediation agent.

[0026] In some preferred embodiments, the fermentation time is 5 to 25 days, and the fermentation temperature is 15 to 55°C.

[0027] In other preferred embodiments, the sulfur-nitrogen chain mixed bacteria include desulfurizing bacteria, nitrogen-fixing bacteria, and Streptomyces.

[0028] As a further preferred embodiment, the desulfurizing bacteria is any one of Desulfovibrio vulgaris (CGMCC 1.5190), Xiamen Desulfovibrio (CGMCC 1.5166), Norwegian Desulfovibrio (CGMCC 1.3493), Escambia River Desulfovibrio (CGMCC1.3481), Mesta Desulfobacillus (CGMCC 1.3477), Rumen Desulfovibrio (CGMCC 1.3470), Desulfovibrio desulfuricans (CGMCC 1.3469), Fructovibrio desulfuricans (CGMCC 1.3468), Rod-shaped Desulfovibrio (CGMCC 1.3467), and Desulfovibrio Gordonia (CGMCC 4.2492).

[0029] As a further preferred embodiment, the nitrogen-fixing bacteria is any one of Azospirillum brasiliensis (CGMCC 1.10379), Azotobacter beijer (CGMCC 1.9044), Rhodobacter nitrofugen (CGMCC 1.5023), Azotobacter armeniaca (CGMCC 1.827), Azotobacter fusca (CGMCC 1.236), Azotobacter iraqiensis (CGMCC 1.8545), Azotobacter vinelandii (CGMCC 1.1649), Azotobacter fusca (CGMCC 1.492), and Azotobacter active (CGMCC 1.5805).

[0030] As a further preferred embodiment, the Streptomyces is Streptomyces oleicolor (CGMCC 4.6559), Streptomyces wiedmore (CGMCC 4.6558), Streptomyces malaysia (CGMCC 4.6557), Streptomyces fine yellow (CGMCC 4.6556), Streptomyces nail spot (CGMCC 4.6555), Streptomyces loucheri (CGMCC 4.6554), Streptomyces litmuscidin (CGMCC 4.6553), Streptomyces aureus (CGMCC 4.6527), Streptomyces nigra (CGMCC 4.6526), ​​Streptomyces grass color (CGMCC 4.6523), Streptomyces light purple gray (CGMCC 4.6516), Streptomyces azure yellow (CGMCC 4.6515), Streptomyces dark heterowall (CGMCC4.6837), Streptomyces grass (CGMCC 4.6837). 4.6835), Streptomyces grisea (CGMCC 4.6969), Streptomyces serrata (CGMCC 4.6968), Streptomyces hiroshimaensis (CGMCC 4.6966), Streptomyces thermovulgaris (CGMCC 4.6962), Streptomyces thermophilic alkalitolerant (CGMCC 4.6961), Streptomyces thermophilic coprophilic (CGMCC 4.6959), Streptomyces olive (CGMCC 4.6958), Streptomyces litmuscidin (CGMCC 4.6956), Streptomyces microti (CGMCC 4.6955).

[0031] It should be noted that the reaction mechanism of the preparation method provided in this embodiment is as follows: sulfur slag, fly ash, and phosphogypsum are mixed. During the aging process, the sulfur slag, fly ash, and phosphogypsum in the sulfur slag mixed gypsum react with each other. CaO in the sulfur slag is hydrolyzed to generate Ca(OH) 2 , the glass in fly ash is Ca 2+ Under the stimulation and continuous erosion, partial depolymerization occurs, forming a small amount of amorphous silicate and aluminum-oxygen tetrahedral monomers, which generate low-polymerization aluminosilicate gel through polycondensation. At the same time, phosphogypsum reacts with fly ash to neutralize acid and alkali and promotes the oxidation of residual sulfur in sulfur slag. The soluble phosphorus and fluorine in phosphogypsum react with Al in fly ash. 2 O 3 , Fe 2 O 3 By chemical adsorption to form complexes (such as AlPO 4 ·nH 2 O, FeF 3 ), while Ca 2+ With F - Generating CaF 2 Precipitation. Some active SiO in fly ash 2 and Al 2 O 3It partially dissolves under weak acidic conditions and reacts with Ca in the system. 2+ 、SO 4 2- The reaction occurs to generate a small amount of ettringite. The sulfate in the mixture combines with the free calcium ions in the phosphogypsum, promoting the transformation of dihydrate gypsum to hemihydrate gypsum, forming a complex interwoven structure. The trace elements in the sulfur slag are adsorbed by the gel layers through ion exchange, and at the same time form phosphate precipitation with the phosphate. The precipitate, the newly generated ettringite and the silica-alumina gel are fully mixed to achieve mineral phase reconstruction. Apple juice concentrate, mulberry puree and raspberry puree are mixed, and the three materials react fully during the stirring process. Apple juice concentrate contains reducing sugars, malic acid, quinic acid, pectin and a small amount of phenolic substances. Mulberry puree is rich in anthocyanins, resveratrol, proanthocyanidins and polyphenols. Raspberry puree is rich in raspberry ketone (4-(p-hydroxyphenyl)-2-butanone), quercetin, ellagic acid and citric acid, polyphenol oxidase, etc. Pectin in apple juice concentrate is easy to combine with its metal ions, resulting in changes in the viscosity of the system. Malic acid can adjust the pH of the mixed system, stabilize anthocyanins in mulberry puree, and affect enzyme activity and redox potential. Resveratrol and polyphenols in mulberry puree are prone to oxidative polymerization, while raspberry ketones are prone to condensation reactions with phenolic substances. Pectinase in apple juice concentrate forms a composite catalytic system with raspberry polyphenol oxidase, resulting in the breakage of pectin molecular chains (viscosity decreases), while accelerating the oxidation of mulberry anthocyanins to colorless chalcone derivatives. Mulberry anthocyanins and raspberry ellagic acid form complexes through π-π stacking and hydrogen bonds, resulting in a shift in the ultraviolet absorption peak. Raspberry quercetin and mulberry resveratrol generate dimers through free radical chain reactions under the action of dissolved oxygen. Pectin hydrolysis products (galacturonic acid) and polyphenol-protein complexes form a gel network through hydrophobic interactions. Raspberry ketone and malic acid are reacted to form raspberry ketone malate. The activated mixture, straw powder, and sulfur-fired coal ash are mixed with gypsum. During the stirring process, the malic acid and citric acid in the activated mixture react with the Ca in the sulfur-fired coal ash system. 2+ , Fe 3+ Chelating reaction of metal ions such as chlorinated polyphenols and phosphogypsum to form soluble metal organic acid salts, which promotes the dissociation of mineral lattices. 2+ Combined with phenol oxygen-calcium bridge bond complex, the recrystallization process of dihydrate gypsum is inhibited, and the free calcium ion concentration in the system is reduced. 2+ Oxidized to Fe 3+ , accelerating the oxidation process of residual sulfur in sulfur slag. Pectinase continuously decomposes pectin to produce galacturonic acid, which reacts with Al in gypsum. 3+The Al-uronic acid complex is formed, destroying the silica network of fly ash glass. The malic acid in the mixed system is dominant, which promotes the cleavage of the β-1,4 glycosidic bond of straw cellulose to generate cellobiose and glucose monomers. Raspberry ketone (4-(p-hydroxyphenyl)-2-butanone) as a natural surfactant penetrates the lignin-hemicellulose composite structure and improves the hydrolysis efficiency. Mulberry anthocyanin and lignin phenylpropane units form a conjugated system through π-π stacking, inhibiting the condensation reaction of lignin. Pectin hydrolysis products (galacturonic acid) react with calcium sulfonate through Ca 2+ Bridge to form a three-dimensional interpenetrating network structure. Aluminosilicate gel and cellulose nanofibers are cross-linked by hydrogen bonds to produce a composite material with a hierarchical pore structure. Resveratrol dimer and FeF 3 The precipitate co-crystallized to form a Fe-O-polyphenol composite phase with photocatalytic activity. Reducing sugars from apple juice concentrate promote the bioreduction of sulfate to S 2- , competing with phosphate in phosphogypsum for Ca 2+ Raspberry ketone achieves Fe through keto-enol tautomerism 3+ / Fe 2+ Cycle, improve the system's electron transfer efficiency. Anthocyanin-chalcone redox couple acts as an electron shuttle, promoting the microbial reduction process of metal ions in sulfur coal ash. Desulfurization bacteria convert sulfur oxides into S 2- The nitrogen-fixing bacteria catalyze N 2 →NH 3 , Streptomyces decomposes complex organic matter through extracellular enzymes. The three form a "sulfur-nitrogen-carbon" cycle coupling system, and desulfurization bacteria provide S 2- Combined with heavy metals, nitrogen-fixing bacteria provide NH 3 Regulate pH and participate in mineral stabilization. Streptomyces decomposes organic matter to release carbon sources to support bacterial proliferation. Alkaline NH produced by nitrogen-fixing bacteria metabolism 3 Neutralize the acidic metabolites produced by desulfurization bacteria, maintain the pH of the system, and ensure the optimal activity of the three bacteria. 2- Coordinated regulation of Fe 3+ / Fe 2+ Redox balance. The hydrophobic elements produced by Streptomyces and the polysaccharides in the extracellular polymers of desulfurization bacteria form a three-dimensional network structure, fix the nitrogen-fixing bacteria at the mineral-organic matter interface, and enhance the colonization efficiency of the bacterial community on the surface of the aluminosilicate gel. The desulfurization bacteria consume the residual sulfate (from the conversion of phosphogypsum) in the system through the sulfate dissimilatory reduction reaction, inhibit the excessive formation of ettringite, and oxidize the residual elemental sulfur in the sulfur slag to generate S by treating the sulfur oxidation residue. 2 O 3 2- , forming an electron transport chain with thioredoxin secreted by Streptomyces, promoting Fe 3+ Reduction to Fe 2+. Azotobacteria produce NH through biological nitrogen fixation 3 Neutralize with organic acids (malic acid, citric acid) in the system to generate NH 4 ⁺-carboxylate buffer system maintains pH stability in the optimal range for the formation of ettringite, and the secreted glutamine synthetase reacts with Al in the aluminosilicate gel 3+ Specific binding inhibits the reconstruction of aluminum oxide octahedrons. The produced phytochelatins form complexes with metal ions, blocking the migration of heavy metals. Streptomyces secretes Cex enzymes to hydrolyze β-1,4 glycosidic bonds in straw, generating cellobiose to provide electron donors for desulfurization bacteria and promote sulfate reduction. The produced actinomycin D inhibits the proliferation of pathogens and activates the inert Fe in fly ash. 2 O 3 Microbial reduction of S. 2- With Ca in aluminosilicate gel 2+ CaS precipitates are generated. NH 4 ⁺Reacts with mulberry anthocyanins through Schiff base to generate stabilized pigment -NH 3 The complex effectively inhibits lignin condensation. Streptomyces β-glucosidase and silicate in fly ash form a composite catalyst, which reduces the activation energy of cellulose hydrolysis. At the same time, the glucose produced by the enzyme participates in the construction of Fe 3+ -sugar acid complex. The biofilm formed by the proliferation of the composite bacteria and the interpenetrating network of ettringite produce a hierarchical pore structure, providing sufficient active sites for heavy metal adsorption. Keto-enol tautomers of raspberry ketone and Fe 3+ / Fe 2+ ⁺Redox pairs build an electron shuttle system to improve the electron transfer efficiency of desulfurization bacteria. The calcium carbonate biofilm formed on the surface of the aluminosilicate gel buffers pH fluctuations, reduces the driving force of gypsum phase change, and loads the bacterial community to form a protective structure. This synergistic system achieves the stabilization of heavy metals by the repair agent through metabolic network coupling, material cycle enhancement and interface reaction optimization.

[0032] In this embodiment, the phosphogypsum and sulfur slag are used in coordination to produce a synergistic effect. The phosphorus element in the phosphogypsum, as one of the essential nutrients for plant growth, can also improve soil fertility to a certain extent and promote the plant repair process. Sulfur slag is a waste product in the sulfur production process. The sulfur element contained in it can be converted into sulfate in the soil environment, and further participates in the chemical balance regulation of the soil. The sulfur element can not only adjust the soil pH to make it more suitable for plant growth, but also form stable sulfide precipitation with heavy metals, thereby reducing the toxicity of heavy metals. At the same time, the crystal structure of calcium sulfate gives it good adsorption properties, especially for heavy metal ions, such as lead, cadmium, mercury, etc., which can effectively fix these harmful substances through ion exchange and surface complexation, reduce their mobility and bioavailability in the soil, and effectively block the path of heavy metals entering the food chain by reducing the content and mobility of heavy metals in the soil. That is to say, by using phosphogypsum and sulfur slag together, on the one hand, the adsorption and fixation capacity of heavy metals can be enhanced, and on the other hand, it can improve the soil structure and enhance the overall ecological function of the soil to create favorable conditions for plant restoration. On the other hand, it can greatly alleviate the pressure of industrial waste on the environment, reduce dependence on primary resources, improve resource utilization efficiency and reduce costs.

[0033] The preparation process provided in this embodiment is simple. By reasonably matching materials and bacterial community structure, full resource utilization of gypsum and sulfur slag is achieved. The heavy metal contaminated soil stabilizer prepared by synergistic fermentation of desulfurization bacteria, nitrogen-fixing bacteria, and Streptomyces has significant performance, can significantly reduce the leaching concentration of heavy metals, and significantly increase the yield of the planted lettuce.

[0034] Another aspect of the present disclosure provides a heavy metal contaminated soil remediation agent, which is prepared by the method described above.

[0035] Another aspect of the present disclosure provides an application of a heavy metal contaminated soil remediation agent in the remediation of heavy metal contaminated soil.

[0036] The soil remediation agent of this embodiment, when used in the remediation of heavy metal contaminated soil, can effectively remove multiple pollutants such as cadmium and mercury. The leaching toxicity of cadmium and mercury ions in the remediated heavy metal pollutant soil is lower than 0.3 mg / L and 0.4 mg / L, respectively. At the same time, it can also provide nutrients for plants and promote their growth. The lettuce yield increase rate is greater than 119%.

[0037] The following is a further description of the method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag and its specific application in conjunction with specific examples: It should be noted that the heavy metal contaminated soil, phosphogypsum, and straw powder raw materials used in the following embodiments are as follows: Preparation of heavy metal contaminated soil: Weigh 1 kg of uncontaminated soil sample, then add 200 mg of cadmium and 200 mg of mercury into the soil sample, add water to the soil at a liquid-to-solid ratio of 1:1 ml / mg, stir evenly, age for 24 hours, and then naturally air-dry to obtain the heavy metal contaminated soil sample for testing; Phosphogypsum: Phosphogypsum is obtained from Guizhou Xifeng Phosphate Mine Co., Ltd. The phosphogypsum sample mainly contains 52.70% SO 3 、37.01%CaO、4.37%SiO 2 、2.07%Al 2 O 3 , 1.63%P 2 O 5 and other ingredients (inevitable impurities and loss on ignition).

[0038] Straw powder: purchased from Shaanxi Jinhe Agricultural Technology Co., Ltd., type: wheat straw powder, brand: Shaanxi Jinhe.

[0039] Example 1 This example uses the effect of the mass ratio of sulfur slag, fly ash, and phosphogypsum on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Sulphur slag, fly ash and phosphogypsum are mixed in a mass ratio of 2.5:20:100, 3:20:100, 4:20:100, 5:12.5:100, 5:15:100, 5:17.5:100, 5:20:100, 15:20:100, 25:20:100, 5:40:100, 15:40:100, 25:40:100, 5:60:100, 15:60:100, 25:60:100, 25:65:100, 25:70:100, 25:75:100, 27.5:60:100, 30:60:100 and 32.5:60:100, stirred evenly and aged for 6 hours to obtain a sulfur-fly ash mixed gypsum material. Apple juice concentrate, mulberry puree and raspberry puree were mixed in a mass ratio of 5:20:100 and stirred evenly to obtain an activated mixture. The activated mixture, straw powder and sulfur coal ash were mixed with gypsum in a mass ratio of 1.5:5:100 and stirred evenly to obtain a mixed fermentation material. Sulfur-nitrogen chain mixed bacteria were added to the mixed fermentation material for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 5 days and the fermentation temperature was 15°C. The sulfur-nitrogen chain mixed bacteria consisted of desulfurization bacteria, nitrogen-fixing bacteria and streptomyces, wherein the desulfurization bacteria was common desulfurization vibrio (CGMCC 1.5190); the nitrogen-fixing bacteria was azospirillum brasiliensis (CGMCC 1.10379); and the streptomyces was olive color-producing streptomyces (CGMCC 4.6559).

[0040] Preparation of repaired heavy metal contaminated soil: The heavy metal contaminated soil remediation agent prepared in this example was mixed with heavy metal contaminated agricultural land soil in a mass ratio of 5:100, stirred evenly, sprinkled with water evenly, and aged for 21 days to obtain repaired heavy metal contaminated agricultural land soil.

[0041] Heavy metal toxicity leaching test: Toxicity leaching test was carried out on heavy metal contaminated soil samples before and after remediation in accordance with the "Solid Waste Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007).

[0042] Detection of cadmium and mercury ion concentration: The mercury concentration in the leachate is determined according to the "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Water Quality by Atomic Fluorescence Method" (HJ694-2014); the cadmium concentration in the leachate is determined according to the "Determination of 65 Elements in Water Quality by Inductively Coupled Plasma Mass Spectrometry" (HJ700-2014).

[0043] Comparative test of lettuce planting: Two identical plots were selected to plant lettuce, No The seedling selection, planting and plant protection process of lettuce were the same for plots 1 and 2. During the entire growth period, no heavy metal contaminated soil remediation agent was applied to plot 1, and heavy metal contaminated soil remediation agent (2 kg per square meter) was applied to plot 2 before seedling planting. After the planting period, the lettuce was harvested, washed, dried and weighed.

[0044] Lettuce yield increase rate: 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 No.1 to obtain the lettuce yield increase rate.

[0045] Table 1 Effect of the mass ratio of sulfur slag, fly ash and phosphogypsum on the performance of the prepared heavy metal contaminated soil remediation agent

[0046] It can be seen from Table 1 that when the mass ratio of sulfur slag, fly ash and phosphogypsum is less than 5:20:100 (such as in Table 1, the mass ratio of sulfur slag, fly ash and phosphogypsum = 5:17.5:100, 5:15:100, 5:12.5:100, 4:20:100, 3:20:100, 2.5:20:100 and lower ratios not listed in Table 1), less sulfur slag and fly ash are added, and the three materials do not react fully, resulting in a decrease in the performance of the prepared heavy metal contaminated soil remediation agent. The concentrations of heavy metal cadmium and mercury ions in the remediated soil increase significantly with the decrease of the mass ratio of sulfur slag, fly ash and phosphogypsum, and the lettuce yield increase rate decreases significantly with the decrease of the mass ratio of sulfur slag, fly ash and phosphogypsum.

[0047] Further reference to Table 1 shows that when the mass ratio of sulfur slag, fly ash, and phosphogypsum is equal to 5~25:20~60:100 (as in Table 1, the mass ratio of sulfur slag, fly ash, and phosphogypsum = 5:20:100, 15:20:100, 25:20:100, 5:40:100, 15:40:100, 25:40:100, 5:60:100, 15:60:100, 25:60:100), sulfur slag, fly ash, and phosphogypsum are mixed. During the aging process, the sulfur slag, fly ash, and phosphogypsum in the sulfur ash mixed gypsum react with each other. CaO in the sulfur slag is hydrolyzed to generate Ca(OH) 2 , the glass in fly ash is Ca 2+ Under the stimulation and continuous erosion, partial depolymerization occurs, forming a small amount of amorphous silicate and aluminum-oxygen tetrahedral monomers, which generate low-polymerization aluminosilicate gel through polycondensation. At the same time, phosphogypsum reacts with fly ash to neutralize acid and alkali and promotes the oxidation of residual sulfur in sulfur slag. The soluble phosphorus and fluorine in phosphogypsum react with Al in fly ash. 2 O 3 , Fe 2 O 3 By chemical adsorption to form complexes (such as AlPO 4 · n H 2 O, FeF 3 ), while Ca 2+ With F - Generating CaF 2 Precipitation. Some active SiO in fly ash 2 and Al 2 O 3 It partially dissolves under weak acidic conditions and reacts with Ca in the system. 2+ 、SO 4 2- A reaction occurs to generate a small amount of calcium sulfonite. The sulfate in the mixture combines with the free calcium ions in the phosphogypsum, prompting the conversion of dihydrate gypsum to hemihydrate gypsum, forming a complex interwoven structure. Trace elements in the sulfur slag are adsorbed between the gel layers through ion exchange, and at the same time form phosphate precipitates with phosphate. The precipitate, the newly generated calcium sulfonite and the silica-alumina gel are fully mixed to achieve mineral phase reconstruction. Ultimately, the leaching toxicity of the repaired heavy metal pollutants, cadmium and mercury ions in the soil, were less than 0.3 mg / L and 0.4 mg / L, respectively, and the lettuce yield increase rate was greater than 119%.

[0048] Further reference to Table 1 shows that when the mass ratio of sulfur slag, fly ash, and phosphogypsum is greater than 25:60:100 (as in Table 1, the mass ratio of sulfur slag, fly ash, and phosphogypsum = 25:65:100, 25:70:100, 25:75:100, 27.5:60:100, 30:60:100, 32.5:60:100 and higher ratios not listed in Table 1), excessive addition of sulfur slag and fly ash causes an imbalance in the material reaction, resulting in a decrease in the performance of the prepared heavy metal contaminated soil remediation agent. The leaching concentrations of heavy metals cadmium and mercury in the remediated soil increase significantly with the further increase in the mass ratio of sulfur slag, fly ash, and phosphogypsum, and the lettuce yield increase rate decreases significantly with the further increase in the mass ratio of sulfur slag, fly ash, and phosphogypsum.

[0049] Therefore, in summary, considering the benefits and costs, when the mass ratio of sulfur slag, fly ash and phosphogypsum is equal to 5~25:20~60:100, it is most conducive to improving the performance of the prepared heavy metal contaminated soil remediation agent.

[0050] Example 2 This example uses the effect of the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Sulfur slag, fly ash and phosphogypsum are mixed in a mass ratio of 25:60:100, stirred evenly, and aged for 15 hours to obtain a sulfur-fly ash-mixed gypsum material. Mix apple juice concentrate, mulberry puree and raspberry puree in a mass ratio of 2.5:20:100, 3:20:100, 4:20:100, 5:12.5:100, 5:15:100, 5:17.5:100, 5:20:100, 15:20:100, 25:20:100, 5:40:100, 15:40:100, 25:40:100, 5:60:100, 15:60:100, 25:60:100, 25:65:100, 25:70:100, 25:75:100, 27.5:60:100, 30:60:100 and 32.5:60:100, stir well to obtain an activated mixture. The activated mixture, straw powder, sulfur-coal ash and gypsum were mixed in a mass ratio of 4.5:15:100, and stirred evenly to obtain a mixed fermentation material. Sulfur-nitrogen chain mixed bacteria were added to the mixed fermentation material for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 15 days, the fermentation temperature was 35°C, and the sulfur-nitrogen chain mixed bacteria consisted of desulfurization bacteria, nitrogen-fixing bacteria and streptomyces, wherein the desulfurization bacteria was Xiamen Desulfurization Bacillus (CGMCC 1.5166); the nitrogen-fixing bacteria was Bailey's nitrogen-fixing bacteria (CGMCC 1.9044); and the streptomyces was Wedmore Streptomyces (CGMCC 4.6558).

[0051] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the cadmium and mercury ion concentration detection, the lettuce planting comparison test, and the calculation of the lettuce yield increase rate are all the same as in Example 1. The test results of this example are shown in Table 2.

[0052] Table 2 Effect of mass ratio of apple juice concentrate, mulberry puree and raspberry puree on the performance of the prepared heavy metal contaminated soil remediation agent

[0053] It can be seen from Table 2 that when the mass ratio of apple juice concentrate, mulberry puree and raspberry puree is less than 5:20:100 (such as in Table 2, the mass ratio of apple juice concentrate, mulberry puree and raspberry puree = 5:17.5:100, 5:15:100, 5:12.5:100, 4:20:100, 3:20:100, 2.5:20:100 and lower ratios not listed in Table 2), less apple juice concentrate and mulberry puree are added, and the three materials and their metabolites do not react fully during the subsequent fermentation process, resulting in a decrease in the performance of the prepared heavy metal contaminated soil remediation agent. The concentrations of heavy metal cadmium and mercury ions in the remediated soil increased significantly with the decrease of the mass ratio of apple juice concentrate, mulberry puree and raspberry puree, and the yield increase rate of lettuce decreased significantly with the decrease of the mass ratio of apple juice concentrate, mulberry puree and raspberry puree.

[0054] Further reference to Table 2 shows that when the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree is equal to 5~25:20~60:100 (such as in Table 2, the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree = 5:20:100, 15:20:100, 25:20:100, 5:40:100, 15:40:100, 25:40:100, 5:60:100, 15:60:100, 25:60:100), apple juice concentrate, mulberry puree, and raspberry puree are mixed, and the three materials react fully during the stirring process. Apple juice concentrate contains reducing sugars, malic acid, quinic acid, pectin, and a small amount of phenolic substances. Mulberry puree is rich in anthocyanidins, resveratrol, proanthocyanidins, and polyphenols. Raspberry puree is rich in raspberry ketone (4-(p-hydroxyphenyl)-2-butanone), quercetin, ellagic acid, citric acid, polyphenol oxidase, etc. Pectin in apple juice concentrate is easy to combine with its metal ions, resulting in changes in the viscosity of the system. Malic acid can adjust the pH of the mixed system, stabilize the anthocyanins in mulberry puree, and affect the enzyme activity and redox potential. Resveratrol and polyphenols in mulberry puree are prone to oxidative polymerization, while raspberry ketone is prone to condensation reaction with phenolic substances. Pectinase in apple juice concentrate and raspberry polyphenol oxidase form a composite catalytic system, resulting in the breakage of pectin molecular chains (viscosity decreases), while accelerating the oxidation of mulberry anthocyanins to colorless chalcone derivatives. Mulberry anthocyanins and raspberry ellagic acid form a complex through π-π stacking and hydrogen bonding, resulting in a shift in the ultraviolet absorption peak. Raspberry quercetin and mulberry resveratrol generate dimers through free radical chain reactions under the action of dissolved oxygen. The pectin hydrolysis product (galacturonic acid) and the polyphenol-protein complex formed a gel network through hydrophobic interaction. Raspberry ketone and malic acid formed raspberry ketone malate through esterification reaction. Finally, the leaching toxicity of cadmium and mercury ions in the repaired heavy metal pollutants in the soil was less than 0.15mg / L and 0.15mg / L, respectively, and the lettuce yield increase rate was greater than 132%.

[0055] Further reference to Table 2 shows that when the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree is greater than 25:60:100 (as in Table 2, the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree = 25:65:100, 25:70:100, 25:75:100, 27.5:60:100, 30:60:100, 32.5:60:100 and higher ratios not listed in Table 2), excessive addition of apple juice concentrate and mulberry puree causes an imbalance in the material reaction, resulting in a decrease in the performance of the prepared heavy metal contaminated soil remediation agent. The leaching concentrations of heavy metals cadmium and mercury in the remediated soil increase significantly with the further increase in the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree, and the yield increase rate of lettuce decreases significantly with the further increase in the mass ratio of apple juice concentrate, mulberry puree, and raspberry puree.

[0056] Therefore, in summary, considering the benefits and costs, when the mass ratio of apple juice concentrate, mulberry puree and raspberry puree is equal to 5~25:20~60:100, it is most conducive to improving the performance of the prepared heavy metal contaminated soil remediation agent.

[0057] Example 3 This example uses the effect of the mass ratio of activated admixture, straw powder, and sulfur-fuel ash mixed with gypsum on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Mix sulfur slag, fly ash and phosphogypsum in a mass ratio of 25:60:100, stir evenly, and age for 24 hours to obtain sulfur fly ash mixed gypsum. Mix apple juice concentrate, mulberry puree and raspberry puree in a mass ratio of 25:60:100, stir evenly to obtain an activated mixture. Mix sulphur slag, fly ash and phosphogypsum in a mass ratio of 0.75:5:100, 1:5:100, 1.25:5:100, 1.5:2.5:100, 1.5:3:100, 1.5:4:100, 1.5:5:100, 4.5:5:100, 7.5:5:100, 1.5:15:100, 4.5:15:100, 7.5:15:100, 1 .5:25:100, 4.5:25:100, 7.5:25:100, 7.5:27.5:100, 7.5:30:100, 7.5:32.5:100, 8:25:100, 8.5:25:100, 9:25:100 Mix the activated mixture, straw powder, sulfur fly ash and gypsum material, stir evenly to obtain the mixed material to be fermented. A sulfur-nitrogen chain mixed bacteria was added to the mixed material to be fermented for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 25 days and the fermentation temperature was 55°C. The sulfur-nitrogen chain mixed bacteria consisted of desulfurization bacteria, nitrogen-fixing bacteria, and streptomyces, wherein the desulfurization bacteria was Norwegian desulfurization bacteria (CGMCC 1.3493); the nitrogen-fixing bacteria was nitrogen-fixing red bacteria (CGMCC 1.5023); and the streptomyces was Malaysian Streptomyces (CGMCC 4.6557).

[0058] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the cadmium and mercury ion concentration detection, the lettuce planting comparison test, and the calculation of the lettuce yield increase rate are all the same as in Example 1. The test results of this example are shown in Table 3.

[0059] Table 3 Effect of the mass ratio of activated mixture, straw powder, and sulfur-fuel ash mixed with gypsum on the performance of the prepared heavy metal contaminated soil remediation agent

[0060] It can be seen from Table 3 that when the mass ratio of the activated mixture, straw powder, and sulfur-coal ash mixed gypsum is less than 1.5:5:100 (such as in Table 3, the mass ratio of the activated mixture, straw powder, and sulfur-coal ash mixed gypsum = 1.5:4:100, 1.5:3:100, 1.5:2.5:100, 1.25:5:100, 1:5:100, 0.75:5:100 and lower ratios not listed in Table 3), the activated mixture and straw powder are added less, and the materials and material metabolites in the subsequent fermentation process are not fully reacted, resulting in the performance of the prepared heavy metal contaminated soil remediation agent decreased. The concentrations of heavy metal cadmium and mercury ions in the remediated soil increased significantly with the decrease of the mass ratio of the activated mixture, straw powder, and sulfur-coal ash mixed gypsum, and the lettuce yield increase rate decreased significantly with the decrease of the mass ratio of the activated mixture, straw powder, and sulfur-coal ash mixed gypsum.

[0061] Further reference to Table 2 shows that when the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed with gypsum is equal to 1.5~7.5:5~25:100 (as in Table 3, the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed with gypsum = 1.5:5:100, 4.5:5:100, 7.5:5:100, 1.5:15:100, 4.5:15:100, 7.5:15:100, 1.5:25:100, 4.5:25:100, 7.5:25:100), the activated mixture, straw powder, and sulfur-fuel ash mixed with gypsum, the malic acid and citric acid in the activated mixture react with the Ca in the sulfur-fuel ash system during the stirring process. 2+ , Fe 3+ Chelating reaction of metal ions such as chlorinated polyphenols and phosphogypsum to form soluble metal organic acid salts, which promotes the dissociation of mineral lattices. 2+ Combined with phenol oxygen-calcium bridge bond complex, the recrystallization process of dihydrate gypsum is inhibited, and the free calcium ion concentration in the system is reduced. 2+ Oxidized to Fe 3+ , accelerating the oxidation process of residual sulfur in sulfur slag. Pectinase continuously decomposes pectin to produce galacturonic acid, which reacts with Al in gypsum. 3+ The Al-uronic acid complex is formed, destroying the silica network of fly ash glass. The malic acid in the mixed system is dominant, which promotes the cleavage of the β-1,4 glycosidic bond of straw cellulose to generate cellobiose and glucose monomers. Raspberry ketone (4-(p-hydroxyphenyl)-2-butanone) as a natural surfactant penetrates the lignin-hemicellulose composite structure and improves the hydrolysis efficiency. Mulberry anthocyanin and lignin phenylpropane units form a conjugated system through π-π stacking, inhibiting the condensation reaction of lignin. Pectin hydrolysis products (galacturonic acid) react with calcium sulfonate through Ca 2+Bridge to form a three-dimensional interpenetrating network structure. Aluminosilicate gel and cellulose nanofibers are cross-linked by hydrogen bonds to produce a composite material with a hierarchical pore structure. Resveratrol dimer and FeF 3 The precipitate co-crystallized to form a Fe-O-polyphenol composite phase with photocatalytic activity. Reducing sugars from apple juice concentrate promote the bioreduction of sulfate to S 2- , competing with phosphate in phosphogypsum for Ca 2+ Raspberry ketone achieves Fe through keto-enol tautomerism 3+ / Fe 2+ Cycle, improve the system's electron transfer efficiency. Anthocyanin-chalcone redox couple acts as an electron shuttle, promoting the microbial reduction process of metal ions in sulfur coal ash. Desulfurization bacteria convert sulfur oxides into S 2- The nitrogen-fixing bacteria catalyze N 2 →NH 3 , Streptomyces decomposes complex organic matter through extracellular enzymes. The three form a "sulfur-nitrogen-carbon" cycle coupling system, and desulfurization bacteria provide S 2- Combined with heavy metals, nitrogen-fixing bacteria provide NH 3 Regulate pH and participate in mineral stabilization. Streptomyces decomposes organic matter to release carbon sources to support bacterial proliferation. Alkaline NH produced by nitrogen-fixing bacteria metabolism 3 Neutralize the acidic metabolites produced by desulfurization bacteria, maintain the pH of the system, and ensure the optimal activity of the three bacteria. 2- Coordinated regulation of Fe 3+ / Fe 2+ Redox balance. The hydrophobic elements produced by Streptomyces and the polysaccharides in the extracellular polymers of desulfurization bacteria form a three-dimensional network structure, fix the nitrogen-fixing bacteria at the mineral-organic matter interface, and enhance the colonization efficiency of the bacterial community on the surface of the aluminosilicate gel. The desulfurization bacteria consume the residual sulfate in the system through the sulfate dissimilatory reduction reaction, inhibit the excessive formation of ettringite, and oxidize the residual elemental sulfur in the sulfur slag to generate S by treating the sulfur oxidation residue. 2 O 3 2- , forming an electron transport chain with thioredoxin secreted by Streptomyces, promoting Fe 3+ Reduction to Fe 2+ . Azotobacteria produce NH through biological nitrogen fixation 3 Neutralize with organic acids (malic acid, citric acid) in the system to generate NH 4 ⁺-carboxylate buffer system maintains pH stability in the optimal range for the formation of ettringite, and the secreted glutamine synthetase reacts with Al in the aluminosilicate gel 3+Specific binding inhibits the reconstruction of aluminum oxide octahedrons. The produced phytochelatins form complexes with metal ions, blocking the migration of heavy metals. Streptomyces secretes Cex enzymes to hydrolyze β-1,4 glycosidic bonds in straw, generating cellobiose to provide electron donors for desulfurization bacteria and promote sulfate reduction. The produced actinomycin D inhibits the proliferation of pathogens and activates the inert Fe in fly ash. 2 O 3 Microbial reduction of S. 2- With Ca in aluminosilicate gel 2+ CaS precipitates are generated. NH 4 ⁺Reacts with mulberry anthocyanins through Schiff base to generate stabilized pigment -NH 3 The complex effectively inhibits lignin condensation. Streptomyces β-glucosidase and silicate in fly ash form a composite catalyst, which reduces the activation energy of cellulose hydrolysis. At the same time, the glucose produced by the enzyme participates in the construction of Fe 3+ -sugar acid complex. The biofilm formed by the proliferation of the composite bacteria and the interpenetrating network of ettringite produce a hierarchical pore structure, providing sufficient active sites for heavy metal adsorption. Keto-enol tautomers of raspberry ketone and Fe 3+ / Fe 2+ ⁺Redox pairs construct an electron shuttle system to improve the electron transfer efficiency of desulfurization bacteria. The calcium carbonate biofilm formed on the surface of the aluminosilicate gel buffers pH fluctuations, reduces the driving force of gypsum phase change, and loads the bacterial community to form a protective structure. This synergistic system achieves the stabilization of heavy metals by the remediation agent through metabolic network coupling, material cycle enhancement, and interface reaction optimization. In the end, the leaching toxicity of cadmium and mercury ions in the repaired heavy metal pollutants in the soil was less than 0.01mg / L and 0.01mg / L, respectively, and the lettuce yield increase rate was greater than 145%.

[0062] Further reference to Table 2 shows that when the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed gypsum is greater than 7.5:25:100 (as in Table 3, the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed gypsum = 7.5:27.5:100, 7.5:30:100, 7.5:32.5:100, 8:25:100, 8.5:25:100, 9:25:100 and higher ratios not listed in Table 3), too much mixture and straw powder are added, and the material reaction is unbalanced, resulting in a decrease in the performance of the prepared heavy metal contaminated soil remediation agent. The leaching concentrations of heavy metals cadmium and mercury in the remediated soil increase significantly with the further increase in the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed gypsum, and the lettuce yield increase rate decreases significantly with the further increase in the mass ratio of the activated mixture, straw powder, and sulfur-fuel ash mixed gypsum. Therefore, in summary, considering the benefits and costs, when the mass ratio of activated admixture, straw powder, and sulfur-fuel ash mixed with gypsum is equal to 1.5~7.5:5~25:100, it is most conducive to improving the performance of the prepared heavy metal contaminated soil remediation agent.

[0063] Example 4 This example uses the effect of desulfurization bacteria on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Mix sulfur slag, fly ash, and phosphogypsum in a mass ratio of 15:40:100, stir evenly, and age for 15 hours to obtain a sulfur-fly ash mixed gypsum material. Mix apple juice concentrate, mulberry puree, and raspberry puree in a mass ratio of 25:60:100, stir evenly, and obtain an activated mixture. Mix the activated mixture, straw powder, and sulfur-fly ash mixed gypsum material in a mass ratio of 7.5:25:100, stir evenly, and obtain a mixed fermentation material. A sulfur-nitrogen chain mixed bacteria was added to the mixed fermentation material for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 25 days and the fermentation temperature was 55°C. The sulfur-nitrogen chain mixed bacteria consisted of desulfurizing bacteria, nitrogen-fixing bacteria and streptomyces, wherein the desulfurizing bacteria were common Desulfovibrio (CGMCC 1.5190), Xiamen Desulfovibrio (CGMCC 1.5166), Norwegian Desulfurizing Microbe (CGMCC 1.3493), Escambia River Desulfurizing Microbe (CGMCC 1.3481), Mesta Desulfobacillus (CGMCC 1.3477), Rumen Desulfovibrio (CGMCC 1.3470), Desulfovibrio desulfuricans (CGMCC 1.3469), Fructose Desulfovibrio (CGMCC 1.3468), and Rod-shaped Desulfurizing Microbe (CGMCC 1.3493). 1.3467), Gordonia desulfurita (CGMCC4.2492); the nitrogen-fixing bacteria is Azotobacter armeniaca (CGMCC 1.827); the Streptomyces is Streptomyces tenuiflavus (CGMCC 4.6556).

[0064] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the cadmium and mercury ion concentration detection, the lettuce planting comparison test, and the calculation of the lettuce yield increase rate are all the same as in Example 1. The test results of this example are shown in Table 4.

[0065] Table 4 Effect of desulfurization bacteria on the performance of the prepared heavy metal contaminated soil remediation agent

[0066] It can be seen from Table 4 that when the desulfurizing bacteria is any one of Desulfovibrio spp., Xiamen Desulfovibrio, Norwegian Desulfovibrio, Escambia River Desulfovibrio, Maestral Desulfovibrio, Rumen Desulfovibrio, Desulfovibrio desulfuricans, Fructovibrio fructovorus, Desulfovibrio rod-shaped Desulfovibrio, and Desulfovibrio Gordonia, there is no significant difference in the cadmium and mercury leaching concentrations and the lettuce yield increase rate achieved.

[0067] Example 5 This example uses the effect of nitrogen-fixing bacteria on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Mix sulfur slag, fly ash, and phosphogypsum in a mass ratio of 25:60:100, stir evenly, and age for 24 hours to obtain a sulfur-fly ash mixed gypsum material. Mix apple juice concentrate, mulberry puree, and raspberry puree in a mass ratio of 15:40:100, stir evenly, and obtain an activated mixture. Mix the activated mixture, straw powder, and sulfur-fly ash mixed gypsum material in a mass ratio of 7.5:25:100, stir evenly, and obtain a mixed fermentation material. A sulfur-nitrogen chain mixed bacteria was added to the mixed fermented material for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 15 days and the fermentation temperature was 35°C. The sulfur-nitrogen chain mixed bacteria consisted of desulfurization bacteria, nitrogen-fixing bacteria and streptomyces, wherein the desulfurization bacteria was Desulfobacillus mesta (CGMCC 1.3477); the nitrogen-fixing bacteria were Azospirillum brasiliensis (CGMCC1.10379), Azotobacter beijer (CGMCC 1.9044), Rhodobacter nitrogena (CGMCC 1.5023), Azotobacter armeniaca (CGMCC 1.827), Azotobacter fusca (CGMCC 1.236), Azospirillum iraqica (CGMCC 1.8545), Azotobacter vinelandii (CGMCC 1.1649), Azotobacter nitrogena (CGMCC 1.492) and Azotobacter nitrogena (CGMCC 1.5023). 1.5805) and Streptomyces is Streptomyces punctatus (CGMCC 4.6555).

[0068] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the cadmium and mercury ion concentration detection, the lettuce planting comparison test, and the calculation of the lettuce yield increase rate are all the same as in Example 1. The test results of this example are shown in Table 5.

[0069] Table 5 Effect of nitrogen-fixing bacteria on the performance of the prepared heavy metal contaminated soil remediation agent

[0070] It can be seen from Table 5 that when the nitrogen-fixing bacteria is any one of Azospirillum brasiliensis, Azotobacter beijerinii, Rhodobacter azotobacter, Azotobacter armeniaca, Azotobacter fusca, Azotobacter iraqia, Azotobacter vinelandii, Azotobacter nigrosus, and Azotobacter active, there is no significant difference in the cadmium and mercury leaching concentrations and the lettuce yield increase rate achieved.

[0071] Example 6 This example uses the effect of Streptomyces on the performance of the prepared heavy metal contaminated soil remediation agent as an example to illustrate the preparation method: Mix sulfur slag, fly ash, and phosphogypsum in a mass ratio of 25:60:100, stir evenly, and age for 24 hours to obtain a sulfur-fly ash mixed gypsum material. Mix apple juice concentrate, mulberry puree, and raspberry puree in a mass ratio of 15:40:100, stir evenly, and obtain an activated mixture. Mix the activated mixture, straw powder, and sulfur-fly ash mixed gypsum material in a mass ratio of 4.5:15:100, stir evenly, and obtain a mixed fermentation material. A sulfur-nitrogen chain mixed bacteria was added to the mixed fermented material for fermentation to obtain a heavy metal contaminated soil remediation agent, wherein the fermentation time was 25 days and the fermentation temperature was 55°C. The sulfur-nitrogen chain mixed bacteria consisted of desulfurization bacteria, nitrogen-fixing bacteria and streptomyces, wherein the desulfurization bacteria was rumen desulfurizing enterobacteria (CGMCC 1.3470); the nitrogen-fixing bacteria was Iraqi Azospirillum (CGMCC1.8545); the streptomyces were olive-chromogenic Streptomyces (CGMCC 4.6559), Wedmore Streptomyces (CGMCC 4.6558), Malaysian Streptomyces (CGMCC 4.6557), fine yellow Streptomyces (CGMCC 4.6556), nail spot Streptomyces (CGMCC 4.6555), Louche Streptomyces (CGMCC 4.6554), litmuscidin Streptomyces (CGMCC 4.6553), golden Streptomyces (CGMCC4.6527), black Streptomyces (CGMCC 4.6526), ​​grass-colored Streptomyces (CGMCC 4.6523), light purple gray Streptomyces (CGMCC4.6516), sky blue yellow Streptomyces (CGMCC 4.6515), dark heterowalled Streptomyces (CGMCC 4.6837), grass-born Streptomyces (CGMCC 4.6835), gray wheel silk Streptomyces (CGMCC 4.6969), straight wheel silk Streptomyces (CGMCC 4.6968), Hiroshima Streptomyces (CGMCC 4.6966), thermo common Streptomyces (CGMCC 4.6962), thermophilic alkali-resistant Streptomyces (CGMCC 4.6961), thermophilic fecal Streptomyces (CGMCC 4.6959), olive Streptomyces (CGMCC 4.6958), Streptomyces litmuscidin (CGMCC4.6956), Streptomyces microti (CGMCC 4.6955).

[0072] The preparation of the repaired heavy metal contaminated soil, the heavy metal toxicity leaching test, the cadmium and mercury ion concentration detection, the lettuce planting comparison test, and the calculation of the lettuce yield increase rate are all the same as in Example 1. The test results of this example are shown in Table 6.

[0073] Table 6 Effect of Streptomyces on the performance of the prepared heavy metal contaminated soil remediation agent

[0074] As can be seen from Table 6, when the Streptomyces is any one of olive-chromogenic Streptomyces, Wedmore Streptomyces, Malaysian Streptomyces, fine yellow Streptomyces, nail-spotted Streptomyces, Louche Streptomyces, litmus-cidal Streptomyces, golden Streptomyces, blackened Streptomyces, grass-colored Streptomyces, light purple gray Streptomyces, sky-blue yellow Streptomyces, dark heterowalled Streptomyces, grassy Streptomyces, gray wheel silk Streptomyces, straight wheel silk Streptomyces, Hiroshima Streptomyces, thermo-common Streptomyces, thermophilic alkali-resistant Streptomyces, thermophilic feces-loving Streptomyces, olive Streptomyces, litmus-cidal Streptomyces, and micro Streptomyces, there is no significant difference in the cadmium and mercury leaching concentrations and the lettuce yield increase rate achieved.

[0075] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but 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 substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A method for preparing a heavy metal contaminated soil remediation agent using phosphogypsum and sulfur slag, characterized in that: The method comprises: The sulfur slag, fly ash and phosphogypsum are mixed, stirred evenly, and aged to obtain a sulfur fly ash mixed gypsum material; Mix apple juice concentrate, mulberry puree and raspberry puree, stir evenly to obtain an activated mixture; The activated mixture, straw powder, and the sulfur-fuel ash mixed with gypsum material are mixed and stirred evenly to obtain a mixed material to be fermented; Add sulfur-nitrogen chain mixed bacteria to the mixed material to be fermented for fermentation to obtain a heavy metal contaminated soil repair agent.

2. The method according to claim 1, characterized in that The mass ratio of the sulfur slag, the fly ash and the phosphogypsum is (5-25):(20-60):

100.

3. The method according to claim 1, characterized in that The aging time is 6 to 24 hours.

4. The method according to claim 1, characterized in that: The mass ratio of the apple juice concentrate, the mulberry puree and the raspberry puree is (5-25):(20-60):

100.

5. The method according to claim 1, characterized in that The mass ratio of the activated admixture, the straw powder and the sulfur fly ash mixed with the gypsum material is (1.5-7.5):(5-25):

100.

6. The method according to claim 1, characterized in that The fermentation time is 5 to 25 days, and the fermentation temperature is 15 to 55°C.

7. The method according to claim 1, characterized in that The sulfur-nitrogen chain mixed bacteria include desulfurizing bacteria, nitrogen-fixing bacteria and Streptomyces.

8. The method according to claim 7, characterized in that The desulfurizing bacteria is any one of Desulfovibrio vulgaris, Xiamen Desulfovibrio, Norwegian Desulfovibrio, Escambia River Desulfovibrio, Maestral Desulfovibrio, Rumen Desulfovibrio, Desulfovibrio desulfuricans, Desulfovibrio fructificans, rod-shaped Desulfovibrio, and Desulfovibrio gordonella; and / or, The nitrogen-fixing bacteria is any one of Azospirillum brasiliensis, Azotobacter beijerii, Rhodobacter azotobacter, Azotobacter armeniaca, Azotobacter fusca, Azotobacter iraqia, Azotobacter vinelandii, Azotobacter fusca, and Azotobacter active; and / or, The streptomyces is any one of olive-chromogenic Streptomyces, Wedmore Streptomyces, Malaysian Streptomyces, fine yellow Streptomyces, nail-spotted Streptomyces, Louche Streptomyces, litmus-killing Streptomyces, golden Streptomyces, blackened Streptomyces, grass-colored Streptomyces, light purple gray Streptomyces, sky blue yellow Streptomyces, dark heterowalled Streptomyces, grassy Streptomyces, gray wheel silk Streptomyces, straight wheel silk Streptomyces, Hiroshima Streptomyces, thermo-common Streptomyces, thermophilic alkali-resistant Streptomyces, thermophilic feces-loving Streptomyces, olive Streptomyces, litmus-killing Streptomyces, and micro Streptomyces.

9. A heavy metal contaminated soil remediation agent, characterized in that: The heavy metal contaminated soil remediation agent is prepared by the method according to any one of claims 1 to 8.

10. Use of the heavy metal contaminated soil remediation agent according to claim 9 in the remediation of heavy metal contaminated soil.

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