A kind of solubility organic matter supplement component optimization regulator and the method for reducing soil dust and heavy metal toxicity

Abstract

This invention discloses a soluble organic matter supplement component optimization adjuster and a method for reducing soil dust and heavy metal toxicity. The soluble organic matter supplement component optimization adjuster comprises a soluble organic matter supplement, an iron-manganese oxide suspension, and a composite cross-linking agent. Applying this supplement to the soil surface through spraying or irrigation effectively promotes the formation of a stable biofilm by soil microbial communities, cementing loose soil particles and thus significantly suppressing dust generation. Simultaneously, the supplemented soluble organic matter supplement fixes heavy metals such as lead in soil particles through adsorption and complexation, reducing their bioavailability and toxic effects. This invention has the advantages of being environmentally friendly, low-cost, long-lasting, and possessing both dust fixation and toxicity reduction effects.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to a soluble organic matter supplement component optimization and adjustment agent and a method for reducing soil dust and heavy metal toxicity. Background Technology

[0002] Urban soil dust is a significant source of inhalable particulate matter (PM10) and fine particulate matter (PM2.5) in ambient air, severely deteriorating air quality and posing a significant threat to public health. One of the root causes of this problem lies in the widespread structural degradation and severe loss of organic matter in urban soils subjected to high-intensity human disturbance (such as construction sites, exposed land, and backfill soil). Such soils are loose in texture and have damaged aggregate structures, resulting in extremely poor resistance to wind erosion and making them highly susceptible to dust generation under dry conditions and wind.

[0003] Currently, the control of soil dust mainly relies on traditional methods such as physical covering, water spraying for dust suppression, and chemical consolidation. For example, while covering with dust nets can block dust sources in the short term, the materials are prone to aging and damage, and their plastic components may cause secondary microplastic pollution. Regular water spraying is simple and easy to implement, but the dust suppression effect is short-lived, and water evaporates rapidly in high-temperature and dry environments, resulting in huge water consumption and the need for frequent operations. Many commercially available chemical dust-solidating agents are often composed of high molecular polymers or inorganic salts. Although they can bind particles, they may change the physical and chemical properties of the soil, inhibit microbial activity, and pose a potential risk of soil and groundwater pollution with long-term use, which is contrary to the goal of ecological restoration.

[0004] From a soil science perspective, healthy soil structure depends on its organic matter, particularly its active dissolved organic matter (DOM) components. DOM is a key mediator of soil ecosystem function, maintaining soil stability and health through mechanisms such as promoting particle aggregation, regulating microbial communities, and influencing pollutant speciation. However, in current technologies, the value of DOM is largely limited to its role as an indicator of soil fertility or a carrier of pollutant migration. Although a few studies have addressed the improvement of soil physical properties by organic amendments, a synergistic remediation technology has yet to be developed that clearly diagnoses "deficiency of soil DOM function" as the core cause, and then proactively and precisely repairs soil's resistance to wind erosion by exogenously supplementing specific functionalized DOM components, while simultaneously achieving in-situ passivation of heavy metals.

[0005] Therefore, given the shortcomings of existing dust control technologies, such as poor ecological compatibility, high resource consumption, or long-term environmental risks, there is an urgent need to develop a new treatment method that is based on soil ecological principles, environmentally friendly, and can simultaneously solve the problem of combined dust and heavy metal pollution. Summary of the Invention

[0006] This invention provides a soluble organic matter supplement component optimization and adjustment agent and a method for reducing soil dust and heavy metal toxicity, solving the problems of poor dust suppression effect, shortened dust suppression period and easy secondary pollution of existing dust suppressants.

[0007] Therefore, it is necessary to provide a soluble organic matter supplement component optimization and adjustment agent, wherein the raw materials of the soluble organic matter supplement component optimization and adjustment agent include soluble organic matter supplement, iron and manganese oxide suspension and composite crosslinking agent; The volume ratio of the soluble organic matter supplement, the iron-manganese oxide suspension, and the composite crosslinking agent is 95-99:0.5-1.5:0.5-2.5. The soluble organic matter supplement is obtained after incubation of organic matter; The composite crosslinking agent includes chitosan, sodium alginate, and microbial extracellular polysaccharides.

[0008] Furthermore, the raw materials for the organic matter are selected from one or more of garden waste, microbial fertilizer, pigeon manure organic fertilizer, or fish protein organic fertilizer.

[0009] Furthermore, the soluble organic matter supplement contains at least three of the following: protein-like substances, tyrosine-like substances, tryptophan-like substances, humic acid-like substances, humic substances, and fulvic acid-like substances.

[0010] Furthermore, the mass ratio of chitosan, sodium alginate, and microbial extracellular polysaccharide is 2-4:1-2:0.5-3.

[0011] The present invention also provides a method for preparing the component optimization and adjustment agent of the soluble organic matter supplement, comprising the following steps: S1. Mix organic matter with solvent, incubate, and then extract to obtain a soluble organic matter supplement; S2. Mix iron salts and manganese salts, adjust the pH, heat the reaction to obtain an iron-manganese oxide suspension; S3. Chitosan and acetic acid are blended together, and sodium alginate and microbial extracellular polysaccharides are added to obtain a composite crosslinking agent; S4. The iron-manganese oxide suspension is mixed with other components to obtain the soluble organic matter supplement component optimization adjuster. Further, in step S2, the heating reaction temperature is 70-80℃.

[0012] Furthermore, the mass ratio of the iron salt to the manganese salt is 0.90-0.95:0.30-0.45.

[0013] This invention also provides a method for reducing soil dust and heavy metal toxicity based on the optimized adjustment of soluble organic matter supplement components, comprising the following steps: The soluble organic matter supplement component optimization adjuster is diluted in water to prepare a working solution, which is then applied to the surface layer of the soil.

[0014] Furthermore, the concentration of the soluble organic matter supplement in the working solution is 100-1000 mg / L.

[0015] Furthermore, the application rate of the working fluid is 0.5-2.0 L / m³. 2 .

[0016] Furthermore, the soil is sandy loam or silty loam.

[0017] Furthermore, the organic matter content of the soil is less than 2%.

[0018] Preferably, the soil is exposed urban soil, construction site soil, or green belt soil.

[0019] This method is specifically designed for sandy loam or silty loam with low organic matter content (<2%) and loose structure (such as bare urban soil and construction sites), and its treatment effect is significant. The conditioner can be easily diluted into a working solution and applied through conventional spraying or irrigation. It does not require complex equipment or significant changes to existing work processes, and is easy to promote and implement in large-scale sites.

[0020] Compared to simple water spraying for dust suppression (with short-term effects), ordinary mulching (high cost and not a fundamental solution), or simply applying passivating agents (limited function and potential alteration of soil properties), this invention provides a comprehensive solution that is long-lasting, low-cost, multifunctional, and ecologically compatible. Starting from enhancing the soil's own structure and function, it achieves a balance between environmental and resource benefits, demonstrating outstanding practical value and promising prospects for application in soil dust control and pollution risk prevention.

[0021] The present invention has the following beneficial effects: This invention combines a soluble organic matter supplement, an iron-manganese oxide suspension, and a biocrosslinking agent through a specific formulation, achieving integrated and synergistic treatment of soil dust and heavy metal (such as lead) pollution. After application, the soluble organic matter supplement rapidly forms a stable biofilm on the surface, physically binding soil particles and effectively suppressing dust generation at the source. Simultaneously, the active functional groups in this component synergistically work with the iron-manganese oxide to strongly complex, adsorb, and passivate free heavy metals in the soil, significantly reducing their bioavailability and mobility, thus achieving the dual purpose of "dust fixation" and "heavy metal fixation." The active organic matter, such as proteins and humic acids, added to the soil surface layer combines with amorphous iron-manganese oxide nanoparticles to form a composite functional group with both organic complexation and inorganic adsorption properties, resulting in a heavy metal fixation capacity far exceeding that of single materials. Furthermore, the added chitosan, sodium alginate, and microbial extracellular polysaccharides act as natural polymer cross-linking agents. Compared to single cross-linking agent components, these agents increase structural density, enhance environmental adaptability, synergistically promote microbial colonization and long-term biological activity, and strengthen the stability and adhesion of the conditioner itself, promoting soil aggregate formation and providing additional heavy metal adsorption sites, thus enhancing the toughness and durability of the surface covering film. Attached Figure Description

[0022] Figure 1 (a) is the ultraviolet-visible absorption spectrum of the soil; Figure 1 (b) is the UV-Vis absorption spectrum of particulate matter; Figure 2 (a)-(h) represent parallel factor analysis of soil three-dimensional fluorescence; Figure 3 (a)-(f) are parallel factor analyses of three-dimensional fluorescence of particulate matter; Figure 4 UV-Vis absorption spectrum of soluble organic matter supplement; Figure 5 This is a four-component loading diagram for a soluble organic matter supplement. Detailed Implementation

[0023] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0024] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0025] It should be understood that, except in any operational instance or otherwise indicated, all figures representing the amounts of ingredients used, for example, in the specification and claims, should be understood to be modified in all cases by the term "about". Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximations varying with the desired performance to be obtained according to the invention.

[0026] Chitosan: 2×10 5 Da was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0027] Sodium alginate: 1.5 × 10 5 Da was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0028] Microbial extracellular polysaccharides: 2×10 6 ~2×10 7 Da was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0029] In the embodiments of this invention, "parts" refers to parts by mass.

[0030] Example 1 Formulation of soluble organic matter supplement component optimization and adjustment agent.

[0031] Determination of missing components in dissolved organic matter supplements for particulate matter: Analysis of the missing components of dissolved organic matter supplements in soil dust particles. First, bare soil, construction site soil, or green belt soil were collected from different functional areas of the city. A dust simulation test was conducted using a simulated wind tunnel test (wind speed of 5 m / s) to obtain residual soil and dust particles.

[0032] The test results are shown in Table 1.1. Figure 1 (a)-(b) and Figure 2-3 As shown; Table 1.1 Amount and characteristics of PM10 in different types of soil dust like Figure 1 As shown in (a)-(b), the UV-Vis absorption spectra of dust particles reveal that the DOM (domestic aromaticity) and humification degree of dust particles are reduced, and the molecular weight is smaller and the hydrophilicity is stronger.

[0033] like Figure 2 (a)-(h) and Figure 3 As shown, three-dimensional fluorescence parallel factorial analysis identified four fluorescent components. Soil contained three types of humic components and one type of protein component, while dust particles contained only two types of humic components and one type of protein component, with the C3 component missing.

[0034] Component C1 (Ex / Em = 230 nm, 435 nm) corresponds to ultraviolet-based fulvic acids, belonging to the smaller molecular weight components of humic substances. Its formation is related to the decomposition products of plant residues and soil organic matter. Component C2 (Ex / Em = 370 nm, 470 nm) corresponds to visible-based humic substances, originating from aged organic matter formed by the long-term decomposition of plant residues or the input of exogenous organic fertilizers. It is highly stable and not easily degraded by microorganisms, and can indicate the maturity of soil organic matter and its long-term carbon sequestration capacity. Component C3 (Ex / Em = 310 nm, 408 nm) belongs to microbial-derived humic substances, closely related to microbial metabolic activities. It is an intermediate product of microbial decomposition of organic matter, with a relatively low molecular weight. Its fluorescence intensity is positively correlated with soil microbial activity. The C4 component (Ex / Em=230nm, 374nm) corresponds to a protein-like substance. It is a non-humic substance and is associated with carboxyl and carbonyl functional groups. It is a soluble microbial metabolite produced by the degradation and metabolism of microorganisms and bacteria. It is easy to bind to large protein molecules and also easy to undergo energy transfer with tyrosine residues bound in the same protein, which has a complex effect on the fluorescence peak.

[0035] C3 component, as a microbial humic substance, is closely related to the metabolic activities of microorganisms in the soil. It mainly originates from the decomposition of microbial remains and the transformation of metabolic products, and is usually found in soil DOM with strong stability and a high degree of humification. The absence of C3 component results in particulate matter DOM being dominated by weakly humified components. Although C2 and C1 components differ in molecular weight, they can both form weak bonds with clay minerals and iron-manganese oxides on the surface of fine particles, and are therefore easily screened. C4 component, due to its smallest molecular weight, is more easily migrated with fine particles.

[0036] Example 2 Preparation of a component optimization and adjustment agent for soluble organic matter supplements.

[0037] 1. Experimental materials: The basic physicochemical properties of straw and sawdust organic fertilizer (Shifang Jiasheng Agricultural Technology Co., Ltd.), pigeon manure organic fertilizer (Baiguo Agricultural Materials (Qingdao) Co., Ltd.), edible mushroom residue and Bacillus subtilis organic fertilizer (Guangdong Tianhe Zhongjia Fertilizer Co., Ltd.), and garden waste are shown in Table 2.2 below.

[0038] Table 2.2 Basic Physicochemical Properties 2. Experimental Procedure 2.1 Extraction Method Take 625 kg of pigeon manure organic fertilizer and dissolve it in 6250 L of water; 156 kg of straw and sawdust organic fertilizer and dissolve it in 1560 L of water; 161 kg of edible mushroom residue and Bacillus subtilis organic fertilizer and dissolve it in 1610 L of water. Using garden waste powder as raw material, take 65 kg of powder and soak it in 130 L of water. Seal the above four fertilizers separately with film and incubate them at room temperature for 15 days.

[0039] Take 50g of each of the four incubated fertilizers and dissolve them in 500ml of deionized water. Shake at 220rpm for 2 hours at 25℃, then centrifuge at 4000rpm for 30 minutes. Filter and collect the supernatant to obtain four soluble organic matter supplements, which will be used as the test solutions.

[0040] 2.2 Determination of Spectral Characteristics of Soluble Organic Matter Supplements a. Ultraviolet-visible spectroscopy measurement: The measurement was performed using an ultraviolet-visible spectrophotometer (Shimadzu UV-2450). The starting wavelength was set to 600 nm and the ending wavelength to 200 nm in a 1 cm quartz cuvette, with a scanning interval of 1 nm.

[0041] b. Three-dimensional fluorescence spectroscopy determination: An F-7000 fluorescence spectrophotometer was used to measure the excitation wavelength Ex = 230-500 nm, the emission wavelength Em = 250-600 nm, the excitation wavelength increment was 5 nm, the emission wavelength increment was set to 2 nm, the scan rate was 2400 nm / min, and the slit width was 10 nm. Raman and Rayleigh scattering were removed before PARAFAC analysis. The fluorescence intensity was normalized to the area under the Milli-Q water Raman peak (Ex = 350 nm) collected on the same day and expressed in Raman units (RU).

[0042] like Figure 4 , Figure 5 It can be seen that the DOM (domestic organic matter) from garden waste sources has lower aromaticity and hydrophobicity; the DOM from straw and sawdust organic fertilizer sources has higher aromaticity and hydrophobicity, relatively lower molecular weight, and higher degree of humification. The DOM from garden waste, pigeon manure organic fertilizer, and straw and sawdust organic fertilizer sources includes both endogenous sources produced by microbial activity and exogenous sources produced by terrestrial plants. In contrast, the DOM from edible mushroom residue and Bacillus subtilis organic fertilizer sources has obvious local source characteristics produced by microbial activity and strong autogenous characteristics, with high bioavailability. The DOM from garden waste sources is more influenced by plants and has fewer autogenous components.

[0043] Example 3 Prepare a component optimization and adjustment agent for soluble organic matter supplements.

[0044] Depending on the source of the soluble organic matter supplement, iron and manganese oxide suspension and composite cross-linking agent were added in proportion, and the content of the components of the adjuster is shown in Table 2.3: Table 2.3 Component Analysis of a Series of Soluble Organic Matter Supplement Component Optimization and Adjustment Agents The preparation method of the soluble organic matter supplement component optimization and adjustment agent includes the following steps: the soluble organic matter supplement, iron and manganese oxide suspension and composite crosslinking agent solution extracted in step 2.1 of Example 2 are mixed and shaken at 220 rpm for 24 h at 25 °C, centrifuged at 4000 rpm for 30 min, and the supernatant (0.45 μm filter membrane) is filtered to obtain the soluble organic matter supplement component optimization and adjustment agent (working solution 1-4).

[0045] The preparation method of the iron-manganese oxide suspension includes the following steps: adding 0.94g FeCl3·6H2O to 50mL of deionized water and stirring for 20min; then adding 20mL of aqueous solution containing 0.35g MnCl2·4H2O and stirring continuously; adjusting the pH to 10 with 30% ammonia water and stirring at 75℃ for 1h to obtain the iron-manganese oxide suspension.

[0046] The preparation method of the composite crosslinking agent includes the following steps: weigh 5g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution, stir until fully dissolved, and then add 2.5g of sodium alginate and 2.5g of microbial extracellular polysaccharide to prepare the composite crosslinking agent.

[0047] The prepared soluble organic matter supplement component optimization modifier was then subjected to vacuum freeze-drying to obtain a solid soluble organic matter supplement component optimization modifier.

[0048] When using, dissolve 1 kg of solid soluble organic matter supplement component optimization adjuster in 1000 L of water and stir until completely dissolved to prepare a series of soluble organic matter supplement component optimization adjuster working solutions with a concentration of 1 g / L.

[0049] Comparative Example 1 (Working Solution 5) A component optimization and adjustment agent for a soluble organic matter supplement. The difference between this comparative example and working solution 1 in Example 3 is that chitosan is used to replace sodium alginate and microbial extracellular polysaccharide of equal mass (i.e., only chitosan is used to replace the composite crosslinking agent), while other components and preparation methods are the same. The preparation method of the composite crosslinking agent includes the following steps: weigh 5g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution, stir evenly and fully dissolve it to prepare the crosslinking agent.

[0050] Comparative Example 2 (Working Solution 6) A component optimization and adjustment agent for a soluble organic matter supplement. The difference between this comparative example and working solution 1 in Example 3 is that the composite crosslinking agent is chitosan and sodium alginate, while the other components and preparation methods are the same. The preparation method of the composite crosslinking agent includes the following steps: weigh 5g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution, stir until fully dissolved, and then add 2.5g of sodium alginate to prepare the composite crosslinking agent.

[0051] Test Example 1 200.00g of different types of soil from Table 1.1 were weighed, and 50ml of different working solutions were applied to each soil. After standing for 24 hours, simulating a wind speed of 5m / s, the Pb content in particulate matter (PM10) was reduced by 54.55% to 90.61%, with working solution 2 showing the highest Pb fixation capacity.

[0052] Table 2.4 Comparison of Dust Control Effects As shown in Table 2.4, all the different soluble organic matter supplement components reduced the Pb content in particulate matter, but the inhibition effects varied significantly among the different working solutions. Among all the tested working solutions, working solution 2 showed the most outstanding performance. Taking construction sites as an example, working solution 2 reduced the Pb content in dust by 50.61% (site 1), 58.67% (site 2), and 59.76% (site 3), significantly better than other working solutions in the same group. In bare soil and green belt soil, working solution 2 also maintained a high lead reduction efficiency, with reduction rates of 53.65%, 36.65%, and 25.43% (bare soil 1-3) and 38.50%, 36.56%, and 47.68% (green belt soil 1-3), respectively. This result indicates that working solution 2 has a good inhibition effect on Pb in dust from different land use types. In comparison, working solutions 5 and 6 had the weakest lead-reducing effect, with a reduction rate of only 4.74% to 13.14%.

[0053] Test Example 2 Application of dust control at urban construction sites A bare construction site in a certain city, with sandy loam soil and an organic matter content of approximately 0.8%, was selected as the test area. Working solution 2 prepared in Example 3 and working solutions 5-6 from Comparative Examples 1-2 were sprayed using a high-pressure sprayer at different dosages (0.5-1.5 L / m²). 2 Spray evenly onto the soil surface. Comparative Example 3 uses an equal amount of water as the working solution.

[0054] Results: Within 24 hours of application, a visible, moist, dark-colored thin layer formed on the surface of the treated area, and soil particle cohesion was significantly enhanced. Under simulated wind conditions (wind speed 5 m / s), the generation of particulate matter (PM10) in the treated area was reduced by more than 50-85% compared to the control group. The effect lasted for approximately 7-25 days, and the biofilm effect persisted even after a light rain.

[0055] Table 2.5 Comparison of dust control effects of working fluid 2 and working fluids 5-6 As shown in Table 2.5, working solution 2 was significantly superior to other working solutions at all dosages. When the application dosage was 0.5, 1.0, and 1.5 L / m², the dust reduction rates of working solution 2 were 49.64%, 75.36%, and 85.13%, respectively, with effective durations of 7, 18, and 25 days, exhibiting a clear dose-response relationship. In contrast, working solution 5, at the same dosage, had reduction rates of only 29.13%, 38.64%, and 53.16%, with effective durations of only 2, 4, and 7 days; working solution 6 had even lower reduction rates of 17.55%, 23.34%, and 39.45%, with effective durations similar to working solution 5. Working solution 7 had the worst dust control effect; even at a high dosage of 1.5 L / m², the reduction rate was only 13.17%, with an effective duration of only 2 days. The above results show that working solution 2 not only has excellent lead reduction capabilities, but also has outstanding advantages in overall control and long-term effectiveness of dust particles, while the control effects of working solutions 5-7 are limited and have no practical application value.

[0056] Test Example 3 Verification of reducing soil lead bioavailability Topsoil from an urban greenbelt near a factory with a lead contamination concentration of 450 mg / kg was collected. In experimental pots, the soil was leveled and sprayed with working solutions 1-4 from Example 3 and working solutions 5-6 from the comparative examples (1 L / m²). 2 After 28 days, the bioavailable form of lead in the soil was determined using the CaCl2 extraction method.

[0057] Table 2.6 Comparison of the effects of bioavailable form control of lead in soil Experimental results: Compared with untreated contaminated soil, the available lead content in soil treated with DOM supplements decreased by approximately 52%. This indicates that the supplemented DOM effectively chelates and fixes lead in the soil, reducing its environmental mobility and plant availability, thereby mitigating the risk of toxicity.

[0058] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0059] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A component optimization and adjustment agent for a soluble organic matter supplement, characterized in that, The raw materials for the soluble organic matter supplement component optimization and adjustment agent include soluble organic matter supplement, iron-manganese oxide suspension and composite crosslinking agent; The volume ratio of the soluble organic matter supplement, the iron-manganese oxide suspension, and the composite crosslinking agent is 95-99:0.5-1.5:0.5-2.

5. The soluble organic matter supplement is obtained after incubation of organic matter; The composite crosslinking agent includes chitosan, sodium alginate, and microbial extracellular polysaccharides.

2. The soluble organic matter supplement component optimization and adjustment agent according to claim 1, characterized in that, The raw materials for the organic matter are selected from one or more of garden waste, microbial fertilizer, pigeon manure organic fertilizer, or fish protein organic fertilizer.

3. The soluble organic matter supplement component optimization and adjustment agent according to claim 1, characterized in that, The mass ratio of chitosan, sodium alginate, and microbial extracellular polysaccharide is 2-4:1-2:0.5-3.

4. A method for preparing the soluble organic matter supplement component optimization adjuster according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix organic matter with solvent, incubate, and then extract to obtain a soluble organic matter supplement; S2. Mix iron salts and manganese salts, adjust the pH, heat the reaction to obtain an iron-manganese oxide suspension; S3. Chitosan and acetic acid are blended together, and sodium alginate and microbial extracellular polysaccharides are added to obtain a composite crosslinking agent; S4. Mix the iron-manganese oxide suspension with other components to obtain the soluble organic matter supplement component optimization adjuster.

5. The preparation method of the soluble organic matter supplement component optimization adjuster according to claim 4, characterized in that, In step S2, the temperature of the heating reaction is 70-80℃.

6. The preparation method of the soluble organic matter supplement component optimization adjuster according to claim 4, characterized in that, The mass ratio of the iron salt to the manganese salt is 0.90-0.95:0.30-0.

45.

7. A method for reducing soil dust and heavy metal toxicity based on the optimized adjustment of soluble organic matter supplement components, characterized in that, Includes the following steps: The soluble organic matter supplement component optimization adjuster obtained according to any one of claims 1-3 is diluted in water to prepare a working solution, and the working solution is applied to the surface layer of the soil.

8. The method for reducing soil dust and heavy metal toxicity based on the optimized adjustment of soluble organic matter supplement components according to claim 7, characterized in that, The concentration of the soluble organic matter supplement in the working solution is 100-1000 mg / L.

9. The method for reducing soil dust and heavy metal toxicity based on the optimized adjustment of soluble organic matter supplement components according to claim 7, characterized in that, The application rate of the working fluid is 0.5-2.0 L / m³. 2 .

10. The method for reducing soil dust and heavy metal toxicity based on the optimized adjustment of soluble organic matter supplement components according to claim 7, characterized in that, The soil is sandy loam or silty loam.

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