Soil remediation material as well as preparation method and application thereof
By constructing a composite material framework from biological straw and coarse coke powder, and combining nano-TiO2 photocatalysis with dual active centers of a metal-carbon matrix, the problem of remediation of heavy metals and organic pollutants in closed coking sites has been solved, achieving efficient and low-cost comprehensive treatment results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 四川省第一地质大队
- Filing Date
- 2026-01-08
- Publication Date
- 2026-04-24
AI Technical Summary
Existing technologies are insufficient for the effective synergistic remediation of heavy metals and organic pollutants, especially polycyclic aromatic hydrocarbons (PAHs), in closed coking sites. Current methods focus on the degradation of organic matter and lack comprehensive remediation and treatment of heavy metals.
A composite material framework is constructed using biological straw and coarse coke powder. Combined with nano-TiO2 photocatalysis and the dual active centers of a metal-carbon matrix, comprehensive remediation of heavy metals and organic pollutants is achieved through photocatalytic reaction and micro-battery effect.
It achieved efficient and synergistic remediation of heavy metals and organic pollutants, improved soil organic matter content, ensured the long-term effectiveness of remediation, and reduced remediation costs.
Smart Images
Figure CN121914741A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soil remediation technology, and in particular to a soil remediation material, its preparation method, and its application. Background Technology
[0002] The production processes of coal gasification and petroleum products are accompanied by the generation of various polycyclic aromatic hydrocarbons (PAHs) and heavy metals. After dry and wet deposition, these PAHs are deposited in the soil. As the number of rings increases, the hydrophobicity and chemical stability of PAHs increase, while their volatility decreases, making it increasingly difficult for PAHs in the soil to degrade, which seriously affects the soil ecological environment.
[0003] Currently, the remediation and treatment of contaminated soil in closed coking sites utilizes methods such as physical remediation, chemical degradation, and bioremediation. Physical remediation methods primarily include thermal desorption, gas-phase extraction, electrokinetic remediation, and supercritical fluid technology. Chemical remediation methods mainly include soil washing, chemical oxidation, plasma degradation, and photocatalytic degradation, which decompose pollutants in the soil into non-toxic small molecules to achieve soil remediation. Bioremediation mainly employs phytoremediation, animal remediation, and microbial remediation, utilizing biological metabolic activities to decompose pollutants in the soil. These remediation methods primarily focus on the degradation and remediation of organic matter, lacking comprehensive remediation and treatment of heavy metals and organic pollutants. Therefore, it is necessary to develop soil remediation materials and methods that synergistically and efficiently degrade and remediate both types of pollutants. Summary of the Invention
[0004] The purpose of this invention is to provide a soil remediation material, its preparation method, and its application, so as to effectively remediate organic pollutants and heavy metal pollution in coking closure sites.
[0005] In view of the above objectives, the present invention provides a method for preparing soil remediation materials, comprising the following steps: S1. Add deionized water to dry coarse coke powder and KOH, mix and stir into a paste, and then calcine and activate at high temperature. Then grind to obtain carbon powder. S2. Dry straw is carbonized at high temperature under a protective atmosphere, cooled, crushed and sieved to obtain straw carbon, humic acid, bentonite and deionized water are added, mixed and granulated, and dried to obtain biocarbon granules. S3. Prepare a nano-TiO2 suspension, mix it with the carbon powder prepared in step S1, and then treat it with ultrasound. After that, dry it under vacuum to obtain an intermediate. S4. The bio-carbon particles prepared in step S2, the intermediate prepared in step S3, the metal glass powder, the binder, and deionized water are mixed, granulated, and dried to obtain the soil remediation material.
[0006] Furthermore, in step S1, the mass ratio of coarse coke powder to KOH is 3:1, the high-temperature roasting temperature is 800℃, and before grinding, the product activated by high-temperature roasting needs to be mixed and stirred with HCl solution for 2 hours, then the solid product is thoroughly washed with deionized water and dried in a vacuum environment at 60℃ for 6 hours.
[0007] Furthermore, in step S2, the temperature of the high-temperature carbonization treatment is 500℃, and the mass ratio of straw carbon, humic acid, and bentonite is 10:1:1.
[0008] Furthermore, in step S3, the preparation of the nano-TiO2 suspension includes weighing 1% of the mass of nano-TiO2 as a dispersant, adding the dispersant and nano-TiO2 sequentially to deionized water to prepare a 30g / L suspension, and stirring at high speed until the suspension is uniform and free of precipitate.
[0009] Furthermore, in step S4, the mass ratio of the bio-carbon particles, intermediate, metallic glass powder, binder, and deionized water is 18:20:5:2-4:9-12, and the binder is sodium alginate or sodium silicate.
[0010] The present invention also provides a soil remediation material, which is prepared by the above-described method for preparing soil remediation materials.
[0011] This invention also provides an application of a soil remediation material, specifically its application in the remediation of soil containing heavy metals and organic pollutants. The soil remediation process includes the following steps: a. Lay an impermeable membrane in the ex-situ remediation area, excavate the contaminated soil and transfer it onto the impermeable membrane, and set up a shade net and LED supplemental lighting above the soil pile; b. Spray deionized water onto the contaminated soil to adjust the soil moisture content to 15-20%, and add soil remediation materials at a ratio of 5-10% of the soil mass. c. Turn on the LED supplemental lighting to initiate the photocatalytic reaction, and periodically till and stir the soil.
[0012] Furthermore, in step c, deionized water is sprayed during tilling and mixing, with a spraying volume of 3-6 L / m².
[0013] The present invention has the following advantages: 1. The soil remediation material of this application utilizes biological straw to construct a carbon source and coarse coke powder to form a composite material skeleton matrix. Combined with a stepwise mixing and loading composite method, it constructs a dual active center of TiO2 photocatalysis and metal (iron)-based carbon matrix, thereby achieving comprehensive remediation and treatment of heavy metals and organic pollutants. The biological straw carbon source, combined with humic acid-activated soil microorganisms, improves the soil organic matter content and ensures the long-term effectiveness of soil remediation and treatment.
[0014] 2. Soil remediation materials are easy to prepare, have abundant raw material sources, and have low soil remediation costs, making them suitable for large-scale application. Attached Figure Description
[0015] Figure 1 This is a SEM image of the soil remediation material. Detailed Implementation
[0016] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.
[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0021] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0022] Example 1
[0023] This embodiment provides a method for preparing soil remediation materials, including the following steps: S1. After removing impurities from the coking plant's coke powder, screen out coke powder with a particle size less than 2mm, dry it with forced air, and then add it to deionized water at a mass ratio of coke powder to KOH powder of 3:1. Adjust the solid-liquid ratio to 1:3, mix and stir to form a paste, and ensure uniform mixing. Then, transfer it to a high-temperature furnace and calcine it at 800℃ under a protective atmosphere of N2 for 3 hours to fully activate it. Continue to introduce N2, and after cooling to below 100℃, remove the solid product, transfer it to a 1mol / L HCl solution and mix and stir for 1 hour. After taking it out, wash it thoroughly with deionized water until the filtrate is neutral, dry it in a vacuum environment at 60℃ for 6 hours, and then grind it to obtain carbon powder for later use.
[0024] Coarse coke powder, as an adsorbent carrier, possesses a high specific surface area, effectively enriching PAHs and heavy metals at a low cost. Activation and etching of the mesopores under high-temperature KOH conditions further enhances its adsorption capacity. Washing with HCl and deionized water thoroughly removes impurities, preventing them from affecting the subsequent construction of photocatalytic sites and microbial activity.
[0025] S2. Select one or more of reed stalks, corn stalks, or sugarcane stalks, cut them, dry them, and then carbonize them at 500℃ for 2 hours under a N2 protective atmosphere. After cooling, crush and sieve to obtain straw carbon. Mix straw carbon, humic acid, and bentonite in a mass ratio of 10:1:1, add deionized water to adjust the moisture content to 20%, granulate, and dry to obtain biochar granules.
[0026] The carbon source constructed by biological straw and the coarse coke powder work together to form the composite material skeleton matrix. Its macroporous structure serves as a mass transfer channel for pollutants, which can accelerate the diffusion of PAHs and heavy metal ions into the material interior. It has high mass transfer efficiency and good enrichment effect. In addition, it can work with humic acid to fully activate soil microorganisms and achieve long-term soil remediation.
[0027] S3. Weigh 1% sodium dodecylbenzenesulfonate (dispersant) of nano TiO2. Add sodium dodecylbenzenesulfonate and nano TiO2 sequentially to deionized water to prepare a 30 g / L suspension. Stir at high speed until the suspension is uniform and free of precipitate to prevent TiO2 agglomeration. Mix with the carbon powder prepared in step S1 and then perform ultrasonic treatment to break up the TiO2 aggregates and make them uniformly adhere to the inner wall of the pores of the carbon powder. Dry in a vacuum environment at 60°C to obtain an intermediate.
[0028] By utilizing dispersants and ultrasonic treatment, TiO2 agglomeration is effectively prevented, solving the problem of pore blockage and ensuring that TiO2 is fully dispersed and loaded within the pores of carbon powder. This increases the density of photocatalytic active sites while maintaining the high specific area of the carbon powder. Furthermore, pre-mixing and loading TiO2 with carbon powder avoids interference with the subsequently constructed micro-battery system.
[0029] S4. The bio-carbon particles prepared in step S2, the intermediate prepared in step S3, metallic glass powder, sodium alginate, and deionized water are mixed in a mass ratio of 18:20:5:3:10, granulated, and dried to obtain the soil remediation material. The metallic glass powder is iron-based, but cast iron powder can also be used. Through the micro-battery effect formed by the porous carbon with coke powder, the reduction efficiency for heavy metals such as Cr, Zn, and Cd is improved.
[0030] Employing two different support carriers effectively enhances the dispersion uniformity of iron-based metallic glass powder / cast iron powder, improving the reduction efficiency of heavy metals. The framework matrix provides a site for adsorption and reaction, while the surface active groups increase the binding force between the composite material and pollutants. A stepwise mixed loading treatment method ultimately forms a collaborative mechanism of TiO2 photocatalysis and a metal (iron)-based carbon matrix dual active centers on the composite material, achieving comprehensive treatment of heavy metal reduction and organic pollutant degradation. Combined with soil microorganisms activated by biochar and humic acid, soil organic matter content is improved, ensuring the long-term effectiveness of soil remediation.
[0031] Example 2
[0032] This embodiment provides a soil remediation material prepared by the method described in Example 1. For example... Figure 1As shown, the composite material exhibits a continuous three-dimensional network structure, indicating a high specific surface area. The surface is covered with densely interconnected micropores, which connect different mesoporous structures, forming continuous mass transfer pathways. The rough inner walls of the pores further increase the specific surface area, enhancing the enrichment effect on PAHs. The uniformly distributed microparticles indicate that TiO2 is uniformly dispersed and attached, effectively ensuring the efficiency of •OH free radical generation and strengthening the oxidative degradation of PAHs. The mesoporous structure serves as the main adsorption site for organic matter, and the rough inner walls increase the contact probability between organic pollutants and active components, improving the adsorption-degradation synergistic efficiency. The irregular shell on the matrix surface indicates that the embedded metal glass powder constructs a widely distributed micro-battery system, verifying the successful synthesis of the soil remediation material. The embedded bonding method enables the Fe... 2+ After release, it can quickly transfer to the carbon-based surface and undergo a reduction reaction with the heavy metal ions adsorbed on the carbon-based surface, thereby reducing the toxicity of the pollution.
[0033] Example 3
[0034] This embodiment provides the application of the soil remediation material of Embodiment 2 in the remediation of soil containing heavy metals and organic pollutants. The soil remediation process includes the following steps: a. Lay an impermeable membrane in the ex-situ remediation area to prevent the spray water from seeping in, excavate the contaminated soil and transfer it to the impermeable membrane, set up a shade net on top of the soil pile to avoid direct sunlight, prevent the soil temperature from being too high and the moisture content from being too low, and set up LED supplementary lights to supplement the photocatalytic reaction. b. Spray deionized water onto the contaminated soil to adjust the soil moisture content to 15-20%, control the moisture content to improve the efficiency of biological carbon release and maintain the photocatalytic activity of TiO2, and add soil remediation materials at a ratio of 5-10% of the soil mass; the amount of soil remediation materials added is implemented according to the specific concentration of soil pollutants, and the concentration of soil pollutants is monitored regularly during the soil remediation cycle, and soil remediation materials can be added in areas with higher local concentrations.
[0035] c. Turn on the LED supplemental lights from 9:00 to 18:00 every day to carry out photocatalytic reaction. Till and stir regularly, and spray deionized water during tilling and stirring at a rate of 3-6L / m² to maintain the soil moisture content at 15-20%. Monitor the soil temperature regularly. If the temperature is higher than 40℃, increase the tilling and stirring frequency.
[0036] Example 4
[0037] Compared to Example 1, in Example 4, the intermediate, metallic glass powder, sodium silicate, and deionized water are in a mass ratio of 18:20:5:2:9. When sodium silicate is used as the binder, it exhibits strong acid and alkali resistance, and the amount of deionized water used can be appropriately reduced compared to sodium alginate.
[0038] Example 5
[0039] Compared with Example 1, in Example 4, the intermediate, metallic glass powder, sodium alginate, and deionized water were in a mass ratio of 18:20:5:4:12.
[0040] Comparative Example 1 Compared with Example 1, in Comparative Example 1, only the nano-TiO2 dispersion treatment was performed in step S3 to obtain nano-TiO2 suspension, while the raw materials in step S4 were adjusted to the nano-TiO2 dispersion prepared in step S3 and the carbon powder prepared in step S1.
[0041] The soil remediation materials prepared in Examples 1, 4, 5, and 6 were used to remediate soil at a closed coking plant site according to the soil remediation process described in Example 3. The results of soil pollutant testing are shown in the table below. Polycyclic aromatic hydrocarbons were determined using liquid chromatography, while heavy metal content was determined using flame atomic absorption spectrophotometry.
[0042] As can be seen from the table above, the soil remediation material of this application can effectively remove PAHs and heavy metals from contaminated soil. Comparing the removal effects of the examples and comparative examples in the table, the composite material obtained by the distributed mixed loading method has a better removal effect than the composite material obtained by one-step mixing. It can be concluded that the distributed mixed loading method can form dual active centers of TiO2 photocatalysis and metal (iron)-based carbon matrix, and can avoid mutual interference between the two.
[0043] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a soil remediation material, characterized in that: Includes the following steps: S1. Add deionized water to dry coarse coke powder and KOH, mix and stir into a paste, and then calcine and activate at high temperature. Then grind to obtain carbon powder. S2. Dry straw is carbonized at high temperature under a protective atmosphere, cooled, crushed and sieved to obtain straw carbon, humic acid, bentonite and deionized water are added, mixed and granulated, and dried to obtain biocarbon granules. S3. Prepare a nano-TiO2 suspension, mix it with the carbon powder prepared in step S1, and then treat it with ultrasound. After that, dry it under vacuum to obtain an intermediate. S4. The bio-carbon particles prepared in step S2, the intermediate prepared in step S3, the metal glass powder, the binder, and deionized water are mixed, granulated, and dried to obtain the soil remediation material.
2. The method for preparing a soil remediation material according to claim 1, characterized in that: In step S1, the mass ratio of coarse coke powder to KOH is 3:1, the high-temperature roasting temperature is 800℃, and before grinding, the product activated by high-temperature roasting needs to be mixed and stirred with HCl solution for 2 hours, and then the solid product is thoroughly washed with deionized water and dried in a vacuum environment at 60℃ for 6 hours.
3. The method for preparing a soil remediation material according to claim 1, characterized in that: In step S2, the high-temperature carbonization treatment temperature is 500℃, and the mass ratio of straw carbon, humic acid, and bentonite is 10:1:
1.
4. The method for preparing a soil remediation material according to claim 1, characterized in that: In step S3, the preparation of nano-TiO2 suspension includes weighing 1% of the mass of nano-TiO2 as a dispersant, adding the dispersant and nano-TiO2 sequentially to deionized water to prepare a 30g / L suspension, and stirring at high speed until the suspension is uniform and free of precipitate.
5. The method for preparing a soil remediation material according to claim 1, characterized in that: In step S4, the mass ratio of the bio-carbon particles, intermediate, metallic glass powder, binder, and deionized water is 18:20:5:2-4:9-12, and the binder is sodium alginate or sodium silicate.
6. A soil remediation material, characterized in that: The soil remediation material is prepared by any one of the soil remediation material preparation methods described in claims 1-5.
7. An application of a soil remediation material, characterized in that: The application of the soil remediation material as described in claim 6 in the remediation of soil containing heavy metals and organic pollutants, wherein the soil remediation process includes the following steps: a. Lay an impermeable membrane in the ex-situ remediation area, excavate the contaminated soil and transfer it onto the impermeable membrane, and set up a shade net and LED supplemental lighting above the soil pile; b. Spray deionized water onto the contaminated soil to adjust the soil moisture content to 15-20%, and add soil remediation materials at a ratio of 5-10% of the soil mass. c. Turn on the LED supplemental lighting to initiate the photocatalytic reaction, and periodically till and stir the soil.
8. The application of a soil remediation material according to claim 7, characterized in that: In step c, deionized water is sprayed during tilling and mixing, with a spraying volume of 3-6 L / m².