Polluted soil nano modifier as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polluted soil treatment, and aims to solve the problems that the existing polluted soil treatment effect is poor, and the original natural ecology of the soil is difficult to recover. The invention provides a polluted soil nano modifier as well as a preparation method and application thereof. The nano modifier is prepared from the following components in percentage by mass: 15 to 60 weight percent of mineral source fulvic acid powder, 3 to 35 weight percent of magnesium oxide powder, 2 to 30 weight percent of aluminum oxide powder, 1 to 5 weight percent of iron oxide powder, 0 to 35 weight percent of titanium oxide powder, 0 to 10 weight percent of vanadium oxide powder, 0 to 25 weight percent of zeolite powder, 0 to 15 weight percent of kaolin powder, 0 to 6 weight percent of aluminosilicate powder and 4 to 8 weight percent of carbon powder. The nano modifier provided by the invention can significantly improve the removal efficiency of composite pollutants in polluted soil, is also suitable for treatment of heavily polluted soil such as oil sludge and the like, can restore the soil to natural ecology, and is beneficial to environmental protection.

Description

Technical Field

[0001] This invention relates to the field of contaminated soil treatment technology, specifically to a nano-modifier for contaminated soil, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of industrialization and urbanization, soil pollution has become an increasingly prominent problem and one of the most concerning environmental issues globally. Among these, the types of pollutants are diverse, and the accumulation of heavy metals and organic pollutants in soil poses a serious threat to ecosystems and human health. In particular, soils contaminated with complex pollutants such as oily sludge are difficult to remediate due to their complex composition, high pollutant mobility, and persistent toxicity. Traditional remediation methods often fail to achieve thorough environmental risk control and ecological restoration.

[0003] Currently, stabilization / solidification technology has been widely adopted for the remediation of such contaminated soils. This technology mainly involves adding agents to the soil to change the form of pollutants or physically encapsulate them, thereby reducing their mobility and bioavailability. However, existing technologies still have certain limitations. For example, the solidification process focuses on encapsulating and isolating pollutants, which can limit pollutant migration to a certain extent, but the remediated soil is often in a blocky or granular state, making it difficult to restore its original aggregate structure and ecological function. While stabilization technology focuses on the transformation of pollutant forms, it often faces problems such as insufficient long-term stability and poor compatibility between remediation materials and soil systems. Therefore, developing a new type of remediation material that can both effectively reduce pollutant activity and promote the restoration of soil ecological functions has become a key technical problem that urgently needs to be solved in the field of contaminated soil remediation.

[0004] Therefore, there is a need in the field for a nano-modifier for contaminated soil, its preparation method, and its application to solve the above problems. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, namely the problem that the treatment of existing contaminated soil is not effective and it is difficult to restore the soil to its original natural ecology.

[0006] This invention provides a nano-modifier for contaminated soil, wherein the nano-modifier comprises, by weight percentage: 15-60 wt% mineral-derived fulvic acid powder, 3-35 wt% magnesium oxide powder, 2-30 wt% aluminum oxide powder, 1-5 wt% iron oxide powder, 0-35 wt% titanium oxide powder, 0-10 wt% vanadium oxide powder, 0-25 wt% zeolite powder, 0-15 wt% kaolin powder, 0-6 wt% aluminosilicate powder, and 4-8 wt% carbon powder.

[0007] In some preferred embodiments, the nano-modifier comprises, by weight percentage: 15-25 wt% mineral-derived fulvic acid powder, 25-35 wt% magnesium oxide powder, 15-25 wt% aluminum oxide powder, 1-3 wt% iron oxide powder, 3-8 wt% titanium oxide powder, 2-5 wt% vanadium oxide powder, 5-15 wt% zeolite powder, 1-5 wt% kaolin powder, 1-3 wt% aluminosilicate powder, and 5-8 wt% carbon powder.

[0008] In some preferred embodiments, the purity of the mineral-derived humic acid powder, zeolite, kaolin powder, and aluminosilicate powder is all above 90%, the purity of the magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder, and vanadium oxide powder is all above 95%, and the purity of the carbon powder is above 85%.

[0009] In some preferred embodiments, the particle size of the mineral fulvic acid powder is ≤150μm, the particle size of the magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder and vanadium oxide powder is 5-20nm, the particle size of the zeolite powder is 1-45μm, the particle size of the kaolin powder is ≤45μm, the particle size of the aluminosilicate powder is ≤75μm, and the particle size of the carbon powder is 10-100μm.

[0010] In some preferred embodiments, the specific surface area of ​​the mineral-derived fulvic acid powder is ≥180 m². 2 / g, the specific surface area of ​​magnesium oxide powder is ≥100m² 2 / g, the specific surface area of ​​alumina powder is 180-250m². 2 / g, the specific surface area of ​​iron oxide powder is 80-150m². 2 / g, the specific surface area of ​​titanium dioxide powder is 90-130m². 2 / g, the specific surface area of ​​vanadium oxide powder is 60-100m². 2 / g, the specific surface area of ​​zeolite powder is 400-600m². 2 / g, the specific surface area of ​​kaolin powder is 50-120m². 2 / g, the specific surface area of ​​aluminosilicate powder is 200-400m². 2 / g, the specific surface area of ​​the toner is 800-1200m². 2 / g.

[0011] The nano-modifier for contaminated soil of the present invention has the following beneficial effects: By synergistically combining mineral-derived fulvic acid with various metal oxides, multiple functions are achieved, including pollutant adsorption, catalytic degradation, and soil structure restoration. Mineral-derived fulvic acid provides active functional groups, enhancing the complexation capacity for heavy metals and organic matter. Components such as iron oxide and titanium oxide enhance the catalytic oxidation reaction through their high specific surface area, effectively decomposing petroleum pollutants. Zeolite and kaolin adsorb and fix small molecule pollutants through their porous structure, reducing their mobility and significantly improving the removal efficiency of complex pollutants.

[0012] This invention also provides a method for preparing the above-mentioned nano-modifier for contaminated soil, the method comprising: S1: Magnesium oxide, aluminum oxide, iron oxide, titanium oxide and vanadium oxide precursors are subjected to high-temperature calcination to obtain the corresponding metal oxides; S2: The metal oxides obtained in step S1, as well as mineral humic acid, zeolite, kaolin, and aluminosilicate, are subjected to high-energy ball milling. S3: Mix the powders obtained in step S2 with the carbon powder using a three-dimensional mixer.

[0013] In some preferred embodiments, in step S1, The titanium dioxide precursor was calcined at 500-550℃ for 2-3 hours; The vanadium oxide precursor was calcined at 450-500℃ for 2-3 hours; The iron oxide precursor was calcined at 600-700℃ for 2-3 hours; Magnesium oxide precursor and aluminum oxide precursor are calcined at 400-600℃ for 2-4 hours.

[0014] In some preferred embodiments, in step S2, the high-energy ball milling time is 6-12 hours, the ball-to-material ratio is (10-15):1, and the rotation speed is 300-500 r / min.

[0015] The preparation method of the nano-modifier for contaminated soil of the present invention has the following beneficial effects: By combining high-temperature calcination of precursors with high-energy ball milling, the controllable synthesis and particle size optimization of metal oxide nanocrystals were achieved. The calcination process enabled the oxides to form stable crystal forms, while the ball milling process controlled the material particle size at the nanoscale and increased the specific surface area. Three-dimensional mixing ensured that each component was evenly dispersed. The modifier prepared by this method has high surface activity and stability, solving the problems of easy agglomeration and poor compatibility of traditional repair materials.

[0016] This invention also provides an application of the above-mentioned nano-modifier for contaminated soil in oily sludge soil, the application including: The nano-modifier was then subjected to high-speed coagulation with the oily sludge soil. The concrete is allowed to undergo aerobic growth in a natural environment to obtain natural ecological soil.

[0017] In some preferred embodiments, the high-speed coagulation is carried out in a mixing device with a mixing speed of 80-120 r / min, a coagulation time of 4-6 minutes, an aeration time of 24-48 hours, and the amount of the nano-modifier added to the oily sludge soil is 100-200 kg / m³. 3 .

[0018] The application of the nano-modifier for contaminated soil of the present invention in oily sludge soil has the following beneficial effects: The nano-modifier is mixed with contaminated soil through high-speed coagulation. Under stirring conditions of 80-120 r / min, rapid dispersion and reaction are achieved. During the coagulation process, the nanomaterials come into full contact with the pollutants and decompose organic toxins through catalytic oxidation. At the same time, fulvic acid promotes the reconstruction of soil aggregate structure. Subsequently, natural oxygenation for 24-48 hours restores the soil's ecological function. All indicators meet the standards. This method has a short remediation cycle, low cost, and does not require pH adjustment, thus avoiding the risk of heavy metal leaching associated with the traditional Fenton method. Attached Figure Description

[0019] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings: Figure 1 This is a test diagram of the nano-modifier for contaminated soil of the present invention in an engineering case. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Based on the problem pointed out in the background art that the existing treatment effect of polluted soil is not good and it is difficult to restore the soil to its original natural ecology, the present invention provides a nano-modifier for polluted soil, its preparation method and application, which aims to improve the treatment efficiency of complex pollutants in polluted soil, and can also be applied to the treatment of heavily polluted soil such as oily sludge, so that it can be restored to its natural ecology.

[0022] The nano-modifier for contaminated soil of the present invention comprises, by weight percentage: 15-60 wt% mineral-derived humic acid powder, 3-35 wt% magnesium oxide powder, 2-30 wt% aluminum oxide powder, 1-5 wt% iron oxide powder, 0-35 wt% titanium oxide powder, 0-10 wt% vanadium oxide powder, 0-25 wt% zeolite powder, 0-15 wt% kaolin powder, 0-6 wt% aluminosilicate powder, and 4-8 wt% carbon powder.

[0023] Preferably, the nano-modifier for contaminated soil comprises, by weight percentage: 15-25 wt% mineral-derived humic acid powder, 25-35 wt% magnesium oxide powder, 15-25 wt% aluminum oxide powder, 1-3 wt% iron oxide powder, 3-8 wt% titanium oxide powder, 2-5 wt% vanadium oxide powder, 5-15 wt% zeolite powder, 1-5 wt% kaolin powder, 1-3 wt% aluminosilicate powder, and 5-8 wt% carbon powder.

[0024] In the above, mineral-derived fulvic acid, as a natural organic matter, forms a stable organic-inorganic hybrid interface through coordination bonding between its active functional groups and the surface of nano-metal oxides. This not only enhances the dispersion stability of the material but also creates an electron transport pathway. Nano-iron oxide undergoes controllable valence state oscillations under the support of a carbon network, achieving a continuous Fenton-like reaction independent of the addition of external hydrogen peroxide. Titanium oxide and vanadium oxide form a Ti-OV heterojunction under carbon doping conditions. The titanium-vanadium heterojunction forms an electron delocalization system under carbon doping, significantly reducing the activation energy barrier for carbon-carbon bond breaking in hydrocarbon compounds. Magnesium oxide and aluminum oxide, as electrolyte cations, utilize their high conductivity and wide electrochemical stability to form a stable electric field in the soil system, promoting the redox reaction of pollutants. The hierarchical porous structure of zeolite and aluminosilicate enables selective adsorption and transformation of pollutants of different molecular sizes. The layered structure of kaolin provides a physical framework for soil aggregate reconstruction. Through the above design, the nano-modifier of this invention can simultaneously solve the complex problems of pollutant chemical transformation and soil ecological function restoration, achieving simultaneous fixation and degradation of pollutants.

[0025] In a preferred embodiment, the purity of the mineral-derived fulvic acid powder, zeolite, kaolin powder, and aluminosilicate powder is all above 90% (inclusive); the purity of the magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder, and vanadium oxide powder is all above 95% (inclusive); and the purity of the carbon powder is above 85% (inclusive). The mineral-derived fulvic acid powder, with a purity of over 90%, ensures a rich content of active functional groups and avoids interference from impurities in the coordination and bonding process. The purity of the metal oxide powders is controlled above 95%, significantly improving the density and uniformity of surface active sites, enabling the catalytic reaction to proceed with higher efficiency. The carbon powder purity is maintained above 85%, ensuring the integrity of its conductive network and electron transport capability. This purity control eliminates uncontrollable factors at the source, resulting in highly consistent and predictable repair effects, providing a reliable quality benchmark for industrial production.

[0026] In some preferred embodiments, the particle size of the mineral fulvic acid powder is ≤150μm, the particle size of the magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder, and vanadium oxide powder is 5-20nm, the particle size of the zeolite powder is 1-45μm, the particle size of the kaolin powder is ≤45μm, the particle size of the aluminosilicate powder is ≤75μm, and the particle size of the carbon powder is 10-100μm. By controlling the catalytic components such as magnesium oxide and aluminum oxide at the 5-20nm scale, the quantum size effect and surface effect of nanomaterials are fully utilized to optimize their catalytic activity. The particle size range of the mineral fulvic acid powder (≤150μm) and the zeolite powder (1-45μm) matches the particle size of the contaminated soil, ensuring uniform dispersion and sufficient contact during the mixing process.

[0027] Preferably, the specific surface area of ​​the mineral-derived fulvic acid powder is ≥180m². 2 / g, the specific surface area of ​​magnesium oxide powder is ≥100m² 2 / g, the specific surface area of ​​alumina powder is 180-250m². 2 / g, the specific surface area of ​​iron oxide powder is 80-150m². 2 / g, the specific surface area of ​​titanium dioxide powder is 90-130m². 2 / g, the specific surface area of ​​vanadium oxide powder is 60-100m². 2 / g, the specific surface area of ​​zeolite powder is 400-600m². 2 / g, the specific surface area of ​​kaolin powder is 50-120m². 2 / g, the specific surface area of ​​aluminosilicate powder is 200-400m². 2 / g, the specific surface area of ​​the toner is 800-1200m². 2 / g, mineral-derived fulvic acid ≥180m 2The high specific surface area of ​​zeolite (400-600m²) provides ample initial adsorption sites for pollutant molecules, while the high specific surface area of ​​zeolite provides sufficient initial adsorption sites for pollutant molecules. 2 The extremely high specific surface area of ​​ / g ensures the ability to deeply capture small molecule pollutants. The specific surface area range of the metal oxide component allows it to expose the maximum number of active catalytic sites while maintaining structural stability. The carbon powder has a specific surface area of ​​800-1200m. 2 The ultra-high specific surface area of ​​ / g constructs a dense electron transport network, providing a basis for continuous electrochemical reduction reactions. This gradient specific surface area design enables each component to play its role in an orderly manner during the remediation process. Pollutants are first enriched through physical adsorption and then catalytically degraded, maximizing the remediation efficiency.

[0028] The preparation method of the nano-modifier for contaminated soil of the present invention includes: S1: Magnesium oxide, aluminum oxide, iron oxide, titanium oxide and vanadium oxide precursors are subjected to high-temperature calcination to obtain the corresponding metal oxides.

[0029] In step S1 above, preferably, the titanium oxide precursor is calcined at 500-550°C for 2-3 hours, the vanadium oxide precursor is calcined at 450-500°C for 2-3 hours, the iron oxide precursor is calcined at 600-700°C for 2-3 hours, and the magnesium oxide and aluminum oxide precursors are calcined at 400-600°C for 2-4 hours. This gradient calcination of the precursors within their respective temperature ranges causes each metal oxide to form a specific crystalline phase. For example, iron oxide preferentially forms the hematite phase (α-F). The coexistence of e2O3 and magnetite phase (Fe3O4) enhances electron conductivity. The anatase phase formed by titanium oxide at 500-550℃ has the optimal surface oxygen vacancy concentration, which enhances catalytic activity. Vanadium oxide can form a suitable non-stoichiometric structure after treatment at 450-500℃, providing abundant oxygen vacancy defects. Calcination of magnesium oxide and aluminum oxide in the range of 400-600℃ can ensure the complete decomposition of precursors and avoid the loss of specific surface area caused by excessive sintering.

[0030] S2: The metal oxides obtained in step S1, as well as mineral humic acid, zeolite, kaolin, and aluminosilicate, are subjected to high-energy ball milling.

[0031] In step S2 above, preferably, the high-energy ball milling time is 6-12 hours, the ball-to-material ratio is (10-15):1, and the rotation speed is 300-500 r / min. According to the inventor's tests, the ball milling time of 6-12 hours ensures sufficient mechanochemical transformation, so that the particles are refined and the surface is activated at the same time. The ball-to-material ratio of 10:1 to 15:1 provides the best impact energy transfer efficiency, which not only ensures the grinding effect, but also avoids the secondary agglomeration of particles caused by excessive ball milling. The rotation speed range of 300-500 r / min has suitable impact energy, which can introduce a large number of dislocations and defects inside the particles. These defects become highly active centers for catalytic reactions. The above parameter combination achieves the best balance between material nano-sizing and activation, significantly improving the surface activity of the final product.

[0032] S3: Mix the powders obtained in step S2 with the carbon powder using a three-dimensional mixer.

[0033] This invention also provides an application of a nano-modifier for contaminated soil in oily sludge soil, comprising: The nano-modifier was subjected to high-speed coagulation with the oily sludge. The high-speed coagulation was carried out in a mixing device at a speed of 80-120 r / min for 4-6 minutes. The dosage of the nano-modifier in the oily sludge was 100-200 kg / m³. 3 ; The concrete is subjected to aerobic growth in a natural environment for 24-48 hours to obtain natural ecological soil.

[0034] In the above process, the high-speed coagulation process generates a strong turbulent shear environment, ensuring that the nano-modifier and contaminated soil quickly form a homogeneous composite system. The natural oxygenation stage provides sufficient reaction time for the system, allowing pollutants to complete the entire process of adsorption-catalysis-degradation on the surface of the modifier. The addition amount of nano-modifier in oily sludge soil is 100-200 kg / m³. 3 While ensuring the effectiveness of soil remediation for oily sludge, the cost of using modifier materials was controlled.

[0035] More preferably, the stirring speed of the stirring device is 100 r / min, and the coagulation time is 5 minutes.

[0036] The technical solution of the present invention will be further illustrated below through several examples of nano-modifiers for contaminated soil.

[0037] Example 1 This embodiment provides a basic type of soil nano-modifier for oily sludge, which, by mass percentage, consists of: 30wt% mineral-derived fulvic acid, 10wt% magnesium oxide, 30wt% aluminum oxide, 2wt% iron oxide, 5wt% titanium oxide, 5wt% vanadium oxide, 5wt% zeolite, 5wt% kaolin, and 8wt% carbon. This formulation constructs a stable matrix with aluminum oxide as the structural carrier. Through the synergistic effect of titanium oxide, iron oxide, and vanadium oxide, it provides reliable photocatalytic and chemical catalytic performance. Combined with a moderate amount of mineral-derived fulvic acid, it activates soil microbial activity and is suitable for treating soils contaminated with medium concentrations of petroleum hydrocarbons, achieving a preliminary balance between catalytic degradation and bioremediation.

[0038] Example 2 This embodiment provides a high-strength catalytic soil nano-modifier, which, by mass percentage, consists of: 15wt% mineral-derived fulvic acid, 8wt% magnesium oxide, 20wt% aluminum oxide, 2wt% iron oxide, 35wt% titanium oxide, 2wt% vanadium oxide, 13wt% zeolite, and 5wt% carbon. This formulation significantly increases the titanium oxide content, aiming to generate a stronger photocatalytic degradation effect, and enhances the Fenton-like reaction efficiency through iron oxide. It is particularly suitable for degrading stubborn organic matter that is difficult to biodegrade, such as polycyclic aromatic hydrocarbons, and has outstanding chemical oxidation ability.

[0039] Example 3 This embodiment provides a highly efficient bio-activated soil nano-modifier, which, by mass percentage, consists of: 60wt% mineral-derived fulvic acid, 5wt% magnesium oxide, 2wt% aluminum oxide, 2wt% iron oxide, 2wt% titanium oxide, 3wt% vanadium oxide, 5wt% zeolite, 12wt% kaolin, 5wt% aluminosilicate, and 4wt% carbon. This formulation significantly increases the proportion of mineral-derived fulvic acid, aiming to strongly stimulate and expand the original microbial community in the soil. It is suitable for petroleum pollutants with good biodegradability, or as a bio-enhancing step after chemical oxidation pretreatment, to achieve complete mineralization of pollutants through biological action.

[0040] Example 4 This embodiment provides a heavy metal stabilization-priority soil nano-modifier, which, by mass percentage, consists of: 15wt% mineral-derived fulvic acid, 35wt% magnesium oxide, 20wt% aluminum oxide, 2wt% iron oxide, 20wt% titanium oxide, 3wt% vanadium oxide, and 5wt% carbon. This formulation focuses on utilizing the alkaline environment of magnesium oxide to stabilize heavy metals, while fulvic acid effectively complexes heavy metal ions. It is particularly suitable for the synergistic treatment of soils contaminated with both petroleum and heavy metals, while degrading organic oil pollution.

[0041] Example 5 This embodiment provides an economical soil nano-modifier, which, by mass percentage, consists of: 38wt% mineral fulvic acid, 5wt% magnesium oxide, 10wt% aluminum oxide, 2wt% iron oxide, 5wt% titanium oxide, 15wt% zeolite, 15wt% kaolin, 2wt% aluminosilicate, and 8wt% carbon. This formulation removes vanadium oxide, which has a high removal cost, and achieves a remediation mechanism based on physical adsorption and biodegradation through a higher proportion of mineral fulvic acid and zeolite, supplemented by basic photocatalysis, significantly reducing material costs while ensuring treatment effectiveness.

[0042] Example 6 This embodiment provides a nano-modifier for acidic soil, which, by mass percentage, consists of: 30wt% mineral-derived fulvic acid, 20wt% magnesium oxide, 20wt% aluminum oxide, 2wt% iron oxide, 20wt% zeolite, 4wt% kaolin, and 4wt% carbon. This formulation significantly increases the proportion of magnesium oxide, fully neutralizing the acidic soil and creating a suitable alkaline or neutral environment for subsequent catalytic reactions and microbial activities, making it particularly suitable for remediation projects in acidic areas.

[0043] Example 7 This embodiment provides a highly efficient degradable soil nano-modifier, which, by mass percentage, consists of: 15wt% mineral-derived humic acid, 15wt% magnesium oxide, 15wt% aluminum oxide, 1wt% iron oxide, 5wt% titanium oxide, 10wt% vanadium oxide, 20wt% zeolite, 9wt% kaolin, 6wt% aluminosilicate, and 4wt% carbon. This ratio significantly increases the proportion of vanadium oxide as a co-catalyst, maximizing the efficiency of photogenerated electron separation, enabling the photocatalytic system to start up rapidly and reach its highest efficiency. It is suitable for emergency treatment scenarios requiring rapid response and efficient degradation.

[0044] Example 8 This embodiment provides an adsorption + catalysis synergistic soil nano-modifier, which, by mass percentage, consists of: 15wt% mineral-derived fulvic acid, 5wt% magnesium oxide, 20wt% aluminum oxide, 1wt% iron oxide, 5wt% titanium oxide, 5wt% vanadium oxide, 25wt% zeolite, 15wt% kaolin, 1wt% aluminosilicate, and 8wt% carbon. This ratio enhances the adsorption and enrichment effect of zeolite, concentrating pollutants around the active sites through its huge specific surface area, creating a favorable local high-concentration environment for subsequent catalytic degradation, and improving the overall reaction rate.

[0045] Example 9 This embodiment provides a balanced and synergistic soil nano-modifier, which, by mass percentage, consists of: 40wt% mineral-derived fulvic acid, 3wt% magnesium oxide, 3wt% aluminum oxide, 5wt% iron oxide, 10wt% titanium oxide, 3wt% vanadium oxide, 20wt% zeolite, 5wt% kaolin, 3wt% aluminosilicate, and 8wt% carbon. This formulation is optimized based on the basic model of Example 1, balancing and increasing the proportion of titanium oxide and iron oxide, making the synergistic effect of photocatalysis, chemical catalysis, and biodegradation more balanced, with stronger universality, and suitable for contaminated sites with complex and varied compositions.

[0046] Example 10 This embodiment provides a high-viscosity oily sludge soil-specific nano-modifier, which, by mass percentage, consists of: 20wt% mineral-derived fulvic acid, 30wt% magnesium oxide, 20wt% aluminum oxide, 2wt% iron oxide, 5wt% titanium oxide, 3wt% vanadium oxide, 10wt% zeolite, 1wt% kaolin, 1wt% aluminosilicate, and 8wt% carbon. This formulation, combined with the alkaline saponification effect of a high proportion of magnesium oxide and the surface activity of mineral-derived fulvic acid, effectively reduces crude oil viscosity, improves the physical state of oily sludge, overcomes mass transfer resistance, and increases treatment efficiency.

[0047] The above Examples 1 to 10 were prepared using the following preparation method: S1: Magnesium oxide, aluminum oxide, iron oxide, titanium oxide and vanadium oxide precursors are subjected to high-temperature calcination to obtain the corresponding metal oxides. Among them, the titanium oxide precursor is calcined at 550℃ for 3 hours, the vanadium oxide precursor is calcined at 500℃ for 3 hours, the iron oxide precursor is calcined at 650℃ for 3 hours, and the magnesium oxide precursor and aluminum oxide precursor are calcined at 500℃ for 3 hours. S2: The metal oxides obtained in step S1, as well as mineral humic acid, zeolite, kaolin, and aluminosilicate, are subjected to high-energy ball milling. The high-energy ball milling time is 12 hours, the ball-to-material ratio is 115:1, and the rotation speed is 450 r / min. S3: Mix the powders obtained in step S2 with the carbon powder using a three-dimensional mixer.

[0048] Then, the contaminated soil nano-modifiers prepared using the above preparation method in Examples 1 to 10 were added at a dosage of 180 kg / m³ in the oily sludge soil. 3 The mixture was added to the sludge soil in the same area in the specified proportions, and coagulation was carried out using a mixing device at a mixing speed of 100 r / min for 5 minutes. The coagulation was then subjected to aerobic growth in a natural environment for 48 hours. The soil conditions before and after the coagulation were compared as shown in the table below. The above comparisons demonstrate that the nano-modifiers in each embodiment of this invention can effectively decompose petroleum pollutants, solving the complex challenges of pollutant chemical transformation and soil ecological function restoration, achieving pollutant passivation and full degradation. Furthermore, the different component ratios in the embodiments also reveal clear technical pathways: Embodiments 2 and 7 achieve optimal pollutant degradation rates and the shortest remediation cycles with high proportions of active components; Embodiment 3 demonstrates deep ecological function restoration through strong stimulation of the microbial community, exhibiting the highest microbial activity index and soil respiration intensity; Embodiments 4 and 6 show better performance in heavy metal fixation and pH adjustment, reflecting targeted stabilization design; Embodiment 10 achieves both high-efficiency degradation and significant viscosity reduction; Embodiment 8 demonstrates outstanding performance in synergistic remediation; and Embodiments 1, 5, and 9 provide a reliable solution with balanced indicators and high cost-effectiveness. Overall, the nano-modifiers provided in each embodiment of this invention constitute a complementary and comprehensive system, allowing users to precisely select the appropriate modifier based on the specific characteristics and remediation priorities of contaminated sites, achieving efficient, safe, and economical customized remediation.

[0049] See Figure 1 , Figure 1 This is an experimental diagram of the treatment of oily sludge soil in a certain area with the soil-contaminated nano-modifier prepared by the above preparation method in Example 10 of the present invention. As can be seen, the treated soil showed only a small amount of oil molecules under electron microscopy, and no combustion phenomenon was observed in the destructive test. For soil with relatively light oily sludge pollution, the nano-modifiers of Example 1, Example 5 and Example 9 can be used to ensure a balance between cost and effect.

[0050] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0052] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present invention as described above, which are not provided in detail for the sake of brevity.

[0053] Although this disclosure has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0054] One or more embodiments of the present invention are intended to cover all such substitutions, modifications, and variations that fall within the scope of protection of the present invention. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of the present invention should be included within the scope of protection of this disclosure.

Claims

1. A nano-modifier for contaminated soil, characterized in that, The nano-modifier, measured by mass percentage, comprises: 15-60 wt% mineral-derived humic acid powder, 3-35 wt% magnesium oxide powder, 2-30 wt% aluminum oxide powder, 1-5 wt% iron oxide powder, 0-35 wt% titanium oxide powder, 0-10 wt% vanadium oxide powder, 0-25 wt% zeolite powder, 0-15 wt% kaolin powder, 0-6 wt% aluminosilicate powder, and 4-8 wt% carbon powder.

2. The nano-modifier for contaminated soil according to claim 1, characterized in that, The nano-modifier, measured by mass percentage, comprises: 15-25 wt% mineral-derived humic acid powder, 25-35 wt% magnesium oxide powder, 15-25 wt% aluminum oxide powder, 1-3 wt% iron oxide powder, 3-8 wt% titanium oxide powder, 2-5 wt% vanadium oxide powder, 5-15 wt% zeolite powder, 1-5 wt% kaolin powder, 1-3 wt% aluminosilicate powder, and 5-8 wt% carbon powder.

3. The nano-modifier for contaminated soil according to claim 2, characterized in that, The purity of mineral-derived humic acid powder, zeolite, kaolin powder, and aluminosilicate powder is all above 90%, while the purity of magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder, and vanadium oxide powder is all above 95%, and the purity of carbon powder is above 85%.

4. The nano-modifier for contaminated soil according to claim 2, characterized in that, The particle size of mineral-derived fulvic acid powder is ≤150μm, the particle size of magnesium oxide powder, aluminum oxide powder, iron oxide powder, titanium oxide powder and vanadium oxide powder is 5-20nm, the particle size of zeolite powder is 1-45μm, the particle size of kaolin powder is ≤45μm, the particle size of aluminosilicate powder is ≤75μm, and the particle size of carbon powder is 10-100μm.

5. The nano-modifier for contaminated soil according to claim 2, characterized in that, The specific surface area of ​​mineral-derived fulvic acid powder is ≥180m². 2 / g, the specific surface area of ​​magnesium oxide powder is ≥100m² 2 / g, the specific surface area of ​​alumina powder is 180-250m². 2 / g, the specific surface area of ​​iron oxide powder is 80-150m². 2 / g, the specific surface area of ​​titanium dioxide powder is 90-130m². 2 / g, the specific surface area of ​​vanadium oxide powder is 60-100m². 2 / g, the specific surface area of ​​zeolite powder is 400-600m². 2 / g, the specific surface area of ​​kaolin powder is 50-120m². 2 / g, the specific surface area of ​​aluminosilicate powder is 200-400m². 2 / g, the specific surface area of ​​the toner is 800-1200m². 2 / g.

6. A method for preparing a nano-modifier for contaminated soil according to any one of claims 2 to 5, characterized in that, The preparation method includes: S1: Magnesium oxide, aluminum oxide, iron oxide, titanium oxide and vanadium oxide precursors are subjected to high-temperature calcination to obtain the corresponding metal oxides; S2: The metal oxides obtained in step S1, as well as mineral humic acid, zeolite, kaolin, and aluminosilicate, are subjected to high-energy ball milling. S3: Mix the powders obtained in step S2 with the carbon powder using a three-dimensional mixer.

7. The method for preparing the nano-modifier for contaminated soil according to claim 6, characterized in that, In step S1, The titanium dioxide precursor was calcined at 500-550℃ for 2-3 hours; The vanadium oxide precursor was calcined at 450-500℃ for 2-3 hours; The iron oxide precursor was calcined at 600-700℃ for 2-3 hours; Magnesium oxide precursor and aluminum oxide precursor are calcined at 400-600℃ for 2-4 hours.

8. The method for preparing the nano-modifier for contaminated soil according to claim 6, characterized in that, In step S2, the high-energy ball milling time is 6-12 hours, the ball-to-material ratio is (10-15):1, and the rotation speed is 300-500 r / min.

9. The application of a nano-modifier for contaminated soil according to any one of claims 1 to 5 in oily sludge soil, characterized in that, The applications include: The nano-modifier was then subjected to high-speed coagulation with the oily sludge soil. The concrete is allowed to undergo aerobic growth in a natural environment to obtain natural ecological soil.

10. The application according to claim 9, characterized in that, The high-speed coagulation is carried out in a mixing device with a mixing speed of 80-120 r / min, a coagulation time of 4-6 minutes, and an oxygenation time of 24-48 hours. The amount of the nano-modifier added to the sludge is 100-200 kg / m³. 3 .

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