Preparation method of wetland soil improvement material capable of sequestration of carbon and increase of sequestration of carbon and improved material

Abstract

The invention provides a preparation method of a carbon-sequestration and sink-increasing wetland soil improvement material and an improvement material.The preparation method comprises the steps that reed biochar and acid-modified attapulgite are subjected to composite granulation, and functional components such as sepiolite, bentonite and a microbial agent are combined, so that a stable organic-inorganic complex can be formed through physical and chemical effects, and the carbon sequestration and sink-increasing wetland soil improvement material is obtained; the soil structure of the wetland is remarkably improved, the carbon immobilization capacity is improved, carbon emission is reduced, the improved material has high mechanical strength and a uniform pore structure, is convenient to apply and not prone to loss, is suitable for complex environments such as estuary wetlands, and the carbon sequestration function is improved, and resources are efficiently utilized.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste resource utilization and wetland ecological restoration materials, and more particularly to a preparation method of a wetland soil improvement material for carbon sequestration and sink enhancement, and the improved material. Background Art

[0002] Wetlands are important carbon storage reservoirs. The anoxic environment formed by long-term or seasonal flooding is not conducive to the mineralization and decomposition of organic matter, thereby promoting the storage of carbon in the soil. However, climate change and human activities have led to wetland degradation and shrinkage, increased wetland carbon emissions, and even transformed them from carbon sinks to carbon sources. Therefore, taking effective measures to enhance wetland soil carbon sequestration and reduce carbon emissions has become a key task in mitigating climate change and achieving the dual carbon goals. Studies have shown that the soil carbon sequestration capacity can be significantly improved by enhancing the protective effect of minerals. For example, calcium ions and active iron oxides can form complexes with organic matter through physical and chemical reactions such as adsorption, co-precipitation, complexation, and encapsulation, reducing the bioavailability and degradation rate of organic carbon. In addition, adding clay minerals such as attapulgite to the soil can also significantly increase the organic carbon content. Attapulgite is a silicate mineral with a special fibrous crystal morphology, a large specific surface area and good adsorption properties. It has attracted much attention because of its environmental friendliness, low cost and easy availability. At the same time, biochar, due to its large specific surface area, loose porosity, high carbon content and difficulty in degradation, can not only exist stably in the soil environment for a long time, but also has strong adsorption and chelation capabilities. At the same time, it can optimize the structure and activity of microbial communities and achieve the dual goals of soil carbon sequestration and emission reduction.

[0003] Although the technology of using biochar and attapulgite to improve soil is gradually increasing, the research on the combination of the two is still insufficient. In the existing technology, biochar and attapulgite are both in powder form. The biochar particle size is small and the density is low, which makes it difficult to apply evenly under complex hydrological conditions such as estuarine wetlands, and there is a large loss. As a clay mineral, attapulgite also faces the problem of inconvenience in application when used alone. In addition, a single material is easily lost due to water erosion in actual application, affecting its long-term effect. Therefore, it is of great significance to develop an improvement material that has the advantages of both biochar and attapulgite, and to solve the loss and uneven distribution problems during the application process through a granulation process. The present invention aims to prepare a new wetland soil improvement material by composite granulation of reed biochar and attapulgite, so as to solve the above-mentioned problems existing in the existing technology and enhance the carbon sequestration function of the wetland. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a preparation method and improvement material for wetland soil improvement materials for carbon sequestration and carbon sink enhancement. Reed biochar and attapulgite are used as the main raw materials, and combined with auxiliary ingredients such as sepiolite, bentonite, and microbial agents through a thermal granulation process to form a granular improvement material with high adsorption performance, stable structure and excellent ecological functions. Furthermore, this material significantly improves the carbon sequestration capacity of wetland soil, improves the physical structure of the soil, enhances microbial activity, and reduces greenhouse gas emissions.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a wetland soil improvement material for carbon sequestration and sink enhancement comprises the following steps: Step S1: putting the reed biochar and acid-modified attapulgite that have been screened and combined by particle size classification into a stainless steel mixing mixer at a mass ratio of 1:5 for preliminary stirring; Step S2: After the initial stirring, 12%-15% of the mixture by weight of sepiolite and 3%-12% of the mixture by weight of bentonite are added to a stainless steel mixer, and 2%-3% of the mixture by weight of nanocellulose and / or 0.08%-0.12% of the mixture by weight of graphene oxide are added, and the mixture is stirred again for 30 minutes. Step S3, adding deionized water accounting for 20% of the total mass to the mixed material after repeated stirring, continuing stirring until the water is evenly distributed, and controlling the final humidity to be 26%-28%; Step S4: sending the mixed material in step S3 into a preheated granulator for granulation to obtain wetland soil improvement material, and then adding microbial agents after the wetland soil improvement material is allowed to stand and cool to room temperature.

[0006] Furthermore, the step S1 includes step S11, soaking the attapulgite in a hydrochloric acid solution with a concentration of 5%-10% for 2-4 hours, then repeatedly washing with deionized water until neutral, and drying in a 60° C. oven to constant weight to obtain acid-modified attapulgite.

[0007] Furthermore, the step S1 includes a step S12, wherein the reed biochar is subjected to a grading and screening process to separate it into two types, namely, coarse particle size and fine particle size, and the two types are evenly mixed in a mass ratio of 2:3 to obtain a combined reed biochar.

[0008] Furthermore, the microbial agent contains Bacillus subtilis and actinomycetes in a ratio of 2:1, and the number of viable bacteria in the agent is not less than 1×10 8 CFU per gram.

[0009] Furthermore, the preheating temperature of the granulator is above 130° C., the compression ratio of the granulator grinding disc is 5.1, and the particle diameter of the wetland soil improvement material is set to 6 mm.

[0010] Furthermore, in step S3, the continuous stirring process adopts a variable speed stirring method, first stirring at a speed of 200-300 rpm for 10 minutes, and then stirring at a speed of 50-100 rpm until the water is evenly distributed, so as to promote full fusion of the components and avoid damage to the activity of the microbial agent.

[0011] A wetland soil improvement material for carbon sequestration and sink enhancement, wherein the pore size distribution of the improvement material is uniform and covers a range of 1.5-12 nm. The improvement material includes a surface layer, a middle layer and a bottom layer of wetland soil.

[0012] Furthermore, the improvement material for the wetland soil surface layer consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite and microbial agents, wherein the sepiolite accounts for 12%-15% of the mass of the mixture and the microbial agents account for 2% of the mass of the mixture.

[0013] Furthermore, the improvement material of the middle layer of the wetland soil consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and nanocellulose, wherein the bentonite accounts for 10%-12% of the mass of the mixture and the nanocellulose accounts for 2%-3% of the mass of the mixture.

[0014] Furthermore, the improvement material of the bottom layer of the wetland soil consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and graphene oxide, wherein the reed biochar accounts for 13%-14% of the mass of the mixture, and the graphene oxide accounts for 0.08%-0.12% of the mass of the mixture.

[0015] The beneficial effects of the present invention are as follows: using reed biochar and attapulgite as the main raw materials, and combining with auxiliary ingredients such as sepiolite, bentonite, and microbial agents through a thermal granulation process, a granular improved material with high adsorption performance, stable structure and excellent ecological function is formed. Furthermore, the material significantly improves the carbon sequestration capacity of wetland soil, improves the physical structure of the soil, enhances microbial activity, reduces greenhouse gas emissions, and is beneficial to plant growth and carbon sequestration. By optimizing the raw material ratio, moisture control and granulation process parameters, the improved material has high adsorption performance, uniform pore size distribution and excellent microstructure. Specifically, the high adsorption performance is achieved through a thermal granulation process and is suitable for high-efficiency carbon sequestration scenarios; the uniform pore size distribution is regulated by a thermal granulation process, which helps to improve the adsorption efficiency of the material; the excellent microstructure significantly improves the particle morphology and pore structure of the material through thermal granulation, further enhancing its functionality, solving the problems of large loss and difficulty in uniform distribution of a single material during application, and significantly improving the carbon sink function of the wetland. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the preparation step of the improved material in the present invention; Figure 2 It is a schematic diagram of the adsorption isotherm in the present invention; Figure 3 Schematic diagram of pore size distribution in the present invention; Figure 4 It is a schematic diagram of the SEM image in the present invention. DETAILED DESCRIPTION

[0017] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a particular component, respectively.

[0018] The present invention provides a preparation method and improved material for wetland soil improvement for carbon sequestration and carbon sink enhancement. The preparation method comprises the following steps: composite granulation of reed biochar and acid-modified attapulgite, and combining with other functional components to form a granular structure with high mechanical strength and stability, thereby optimizing the physical structure of wetland soil and improving carbon sequestration capacity; the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings and specific examples.

[0019] In a degraded estuarine wetland ecological restoration project, soil improvement materials were applied, such as Figure 1As shown, first, reed biochar and acid-modified attapulgite need to be put into a stainless steel mixing mixer in a mass ratio of 1:5 for preliminary mixing. The mixer drives the stirring shaft through a motor to drive the spiral blade to operate at a speed of 120 rpm to ensure that the two raw materials are fully mixed within 15 minutes. During this process, the reed biochar needs to be graded and screened to be divided into two types of coarse and fine particle sizes, and mixed evenly in a mass ratio of 2:3; the acid-modified attapulgite needs to be soaked in a hydrochloric acid solution with a concentration of 5%-10% for 2-4 hours, and then repeatedly washed with deionized water until neutral, and placed in a 60°C oven to dry until constant Heavy, acid-modified attapulgite plays an important adsorption role in the improved material. After the number of its surface active sites increases significantly, it can efficiently adsorb organic matter and heavy metal ions in the soil. Specifically, during the acid modification process, the hydrochloric acid solution selectively dissolves and removes some impurities, exposing more silicon-aluminum active sites. These sites form chemical bonds with organic matter and heavy metals, thereby fixing them inside the material. This fixation effect not only improves soil carbon sequestration, but also reduces the potential harm of pollutants to wetland ecosystems. The above pretreatment steps ensure that the raw materials have good physical properties, providing the basic conditions for subsequent water addition and granulation processes.

[0020] After the initial stirring is completed, 12%-15% of sepiolite, 3%-12% of bentonite, 2%-3% of nanocellulose and / or 0.08%-0.12% of graphene oxide are added to the mixture and stirred again for 30 minutes. The synergistic effect of sepiolite and bentonite further optimizes the physical and chemical properties of the wetland soil. Sepiolite has a layered structure and can absorb water and swell in a humid environment, fill the pores in the soil, and enhance the overall adhesion of the material. Bentonite, due to its high cation exchange capacity, adjusts the pH value of the soil to maintain it in a range suitable for microbial activity. The ratio of the mineral components of the two is precisely controlled to ensure the adaptability and stability of the material in different wetland environments. The wetland soil improvement material is then allowed to stand and cool to room temperature before adding microbial agents.

[0021] The introduction of microbial agents has injected active factors into the wetland ecosystem. Bacillus subtilis and actinomycetes have different functions: Bacillus subtilis decomposes organic matter to release soluble nutrients, while actinomycetes decompose stubborn organic matter, improve soil structure, and inhibit pathogens, forming functional complementarity with Bacillus subtilis to jointly promote carbon cycling and sequestration. The joint action of these microorganisms accelerates the decomposition and transformation of organic matter, increases soil nutrient content, and promotes plant photosynthesis and carbon fixation; at the same time, Bacillus also has the effect of promoting humification, which is beneficial to the formation of high-molecular organic matter and the realization of carbon fixation. At the same time, the carbon dioxide produced during microbial metabolism is captured by the microporous structure of reed biochar, forming a closed loop of carbon cycle and improving the carbon fixation capacity of the wetland.

[0022] The spray device sprays water evenly onto the surface of the mixture, with the nozzle direction perpendicular to the raw material contact surface to ensure that the water can quickly penetrate into the raw material. The spiral agitator continuously stirs the raw material to make the water distribution more even. The humidity detection equipment is installed at the outlet of the mixer. Its probe is in direct contact with the raw material, monitoring the humidity changes in real time and transmitting the data to the control panel. The operator adjusts the spray volume based on the feedback to ensure that the final humidity is maintained between 26% and 28%. This humidity range ensures that the raw material has good plasticity and adhesion, meeting the requirements of the granulation process.

[0023] After entering the hot granulation stage, the flat die rotary pelletizer starts to idle for 18 minutes to preheat the equipment. As the equipment runs, the internal temperature of the pelletizer gradually rises to above 130°C. At this time, the equipment reaches the appropriate pelletizing temperature, the particle diameter is set to 6 mm, the grinding disc compression ratio is adjusted to 5.1, and the feed speed and discharge speed are set to 10 kg and 8 kg per minute respectively. Under high temperature and high pressure conditions, the reed biochar and attapulgite are further tightly combined to form a hot granulation improved material with certain mechanical strength. This process promotes the softening of the raw material surface through high temperature, enhances the bonding force between particles, and thus improves the stability of the finished product.

[0024] In addition, comparative example 1: cold granulation and comparative example 2: mixed modifier are provided, wherein the cold granulation is to feed the mixture in step S3 into a disc granulator for direct granulation; the mixed modifier is to directly mix the reed biochar with the acid-modified attapulgite or the mixture stirred in step S3.

[0025] As shown in Table 1 below:

[0026] Table 1 shows that the specific surface area and pore size distribution of different soil conditioners vary significantly. Compared to the other two soil conditioners, the thermal granulation conditioner has the highest BET specific surface area and pore volume. Its high pore volume supports large-capacity adsorption, while its smaller average pore size enhances the capillary condensation mechanism, potentially providing more adsorption sites and delivering optimal overall adsorption performance. These significant advantages make it more effective in soil applications.

[0027] Figure 2 The N2 adsorption-desorption isotherm curves of the mixed modifier, the hot granulation modifier and the cold granulation modifier are shown in FIG. 1 . It can be seen from the curves that the adsorption amount of the hot granulation modifier in the high pressure zone is significantly higher than that of the cold granulation modifier and the mixed modifier, indicating that the hot granulation modifier may have a stronger overall adsorption capacity.

[0028] Figure 3 The results include the pore size distribution diagram of the mixed modifier, the pore size distribution diagram of the hot granulation modifier and the pore size distribution diagram of the cold granulation. The results show that the granulation modifier has a higher micropore / mesopore volume, and the material has stronger adsorption performance and carbon fixation capacity.

[0029] The final composite particles have a regular spherical appearance, a particle size range of 4-8mm, a density of 1.2-1.5g / cm3, and a porosity of 45%-50%. The surface roughness of the composite particles is relatively high, which can effectively adsorb and fix organic matter and inorganic minerals in wetland soil. The loose porous structure of reed biochar is combined with the fibrous crystal form of attapulgite to form a stable organic-inorganic complex. This composite structure significantly enhances the carbon fixation capacity of the particles through mechanisms such as physical adsorption and co-precipitation. Figure 4 Scanning electron micrographs of a mixed amendment, a hot-granulated amendment, and a cold-granulated amendment were presented, clearly demonstrating the internal structure and surface morphology of the amendments. The results showed that the surface of the granulated amendment was covered with a large amount of granular material. While the internal structure of the amendment retained the basic lamellar structure of reed biochar, the granulation process significantly altered its pore size and volume. Electron microscopy observations further demonstrated that attapulgite effectively aggregated with the reed biochar.

[0030] When the composite particles are applied to wetland soil, their particle size range and density are moderate, which makes them easy to distribute evenly under complex hydrological conditions and not easily dispersed by water flow. The application amount is 1-2 kilograms per square meter. In the wetland environment, the composite particles absorb and fix organic matter through their large specific surface area and special pore structure, thereby reducing carbon emissions. At the same time, they improve the physical structure of the wetland soil, increase soil porosity, and promote oxygen diffusion, thereby optimizing the structure and activity of microbial communities and achieving the dual goals of carbon sequestration and emission reduction in wetland soils.

[0031] Through the adsorption test of the modifier on humic acid solution (10 mg / L), the effects of the control group (CK), the mixed modifier treatment group, the hot granulation modifier treatment group and the cold granulation modifier treatment group on the greenhouse gas CH4 and CO2 fluxes were analyzed, as shown in Table 2 below:

[0032] Among them, Table 2 shows that the granulation modifiers have an inhibitory effect on greenhouse gas emissions from humic acid solution. For CH4 emissions, there is little difference between the treatment groups of each modifier and the control group, among which the thermal granulation modifier has a more obvious reduction; for CO2 flux, the control group showed net emission, while all the modifier treatment groups showed absorption, among which the thermal granulation modifier had the strongest absorption effect, indicating that high temperature treatment enhances carbon fixation capacity.

[0033] In practical applications, the preparation and application of improved materials must strictly follow the above-mentioned process parameters and operating procedures. For example, soil improvement materials were applied to a degraded wetland in a certain estuary. Regular monitoring after application found that the organic carbon content of the wetland soil was significantly increased, microbial activity was enhanced, and greenhouse gas emissions were reduced. This shows that the improved materials have good carbon sequestration and ecological adaptability in wetland ecosystems. The entire preparation process is simple and easy, the reaction environment is easy to achieve, and the granulation process can be completed in the same equipment, which is easy to operate and saves time and effort.

[0034] In summary, the present invention solves the problems of high loss and difficulty in uniform distribution during application of existing single materials by combining reed biochar with attapulgite. The composite particles have high mechanical strength and stability, can exist in wetland environments for a long time, and reduce losses caused by water erosion. At the same time, reed biochar is derived from waste generated during agricultural production, is inexpensive and easy to collect, and achieves efficient resource utilization. The entire preparation process is simple and easy, the reaction environment is easy to achieve, and the granulation process can be completed in the same equipment, which is simple to operate and saves time and effort.

[0035] In addition, the improved materials include the surface layer of wetland soil, the middle layer of wetland soil and the bottom layer of wetland soil; since in the wetland ecosystem, the surface layer is in direct contact with the water body, it is a key area for pollutant interception and preliminary purification. The improved materials for the surface layer of wetland soil are composed of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite and microbial agents. Sepiolite accounts for 12%-15% of the mass of the mixture, and its fibrous structure forms a dense adsorption network, which has high adsorption capacity for organic pollutants, heavy metal ions, etc. suspended in the water body. Microbial agents account for 2% of the mass of the mixture. The rich microbial flora can quickly attach and grow on the surface of sepiolite, use the adsorbed pollutants as a nutrient source, decompose and transform them through metabolic activities, and achieve the dual goals of pollutant removal and carbon fixation. At the same time, the extracellular polymers secreted by microorganisms during the metabolic process can further enhance the material's adsorption performance for pollutants.

[0036] The middle layer of wetland soil is located in the main distribution area of plant roots, which is crucial to plant growth and material stability. The improved materials in the middle layer of wetland soil are composed of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and nanocellulose. Bentonite accounts for 10%-12% of the mass of the mixture. The gel-like structure formed by its water-swelling properties can effectively fill the pores of the material, enhance the overall density and compressive strength of the material, and provide a stable support environment for plant roots. Nanocellulose accounts for 2%-3% of the mass of the mixture. With its excellent mechanical properties, it forms a nano-scale reinforced network inside the material, further improving the toughness and durability of the material. In addition, the high specific surface area and rich hydroxyl groups of nanocellulose can adsorb and retain water and nutrients in the soil, promote the absorption of nutrients by plant roots, and indirectly help improve the carbon sequestration function of wetland ecosystems.

[0037] The bottom layer of wetland soil is the foundation layer of wetland soil and plays a key role in improving the physical and chemical properties of soil. The improved materials of the bottom layer of wetland soil are composed of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and graphene oxide. Reed biochar accounts for 13%-14% of the mass of the mixture. Its developed pore structure has a strong ability to retain water and fertilizer, which can regulate the moisture content of the bottom soil and provide a suitable living environment for microorganisms; at the same time, the functional groups on the surface of biochar can adsorb and fix heavy metal ions in the soil, reducing their biological effectiveness. The mass proportion of graphene oxide is 0.08%-0.12%. Its unique two-dimensional conductive network structure can accelerate electron transfer, affect the respiration and metabolic activities of microorganisms, optimize the redox environment of the bottom soil, accelerate the humification process and carbon fixation of soil organic matter, and improve the overall stability of the wetland ecosystem.

[0038] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that do not depart from the principles of the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a wetland substrate improvement material for carbon sequestration and sink enhancement, characterized by: The following steps are involved: Step S1: putting the reed biochar and acid-modified attapulgite that have been screened and combined by particle size classification into a stainless steel mixing mixer at a mass ratio of 1:5 for preliminary stirring; Step S2: After the initial stirring, 12%-15% of the mixture by weight of sepiolite and 3%-12% of the mixture by weight of bentonite are added to a stainless steel mixer, and 2%-3% of the mixture by weight of nanocellulose and / or 0.08%-0.12% of the mixture by weight of graphene oxide are added, and the mixture is stirred again for 30 minutes. Step S3, adding deionized water accounting for 20% of the total mass to the mixed material after repeated stirring, continuing stirring until the water is evenly distributed, and controlling the final humidity to be 26%-28%; Step S4: sending the mixed material in step S3 into a preheated granulator for granulation to obtain wetland soil improvement material, and then adding microbial agents after the wetland soil improvement material is allowed to stand and cool to room temperature.

2. The method for preparing a wetland soil improvement material for carbon sequestration and sink enhancement according to claim 1, characterized in that: The step S1 includes step S11, wherein the attapulgite is soaked in a hydrochloric acid solution with a concentration of 5%-10% for 2-4 hours, then repeatedly washed with deionized water until neutral, and dried in an oven at 60° C. to constant weight to obtain acid-modified attapulgite.

3. The method for preparing a wetland soil improvement material for carbon sequestration and sink enhancement according to claim 2, characterized in that: The step S1 includes step S12, wherein the reed biochar is subjected to a grading and screening process to be divided into two types, namely, coarse particle size and fine particle size, and the reed biochar is evenly mixed in a mass ratio of 2:3 to obtain a combined reed biochar.

4. The method for preparing a wetland substrate improvement material for carbon sequestration and sink enhancement according to claim 1 or 3, characterized in that: The microbial agent contains Bacillus subtilis and actinomycetes in a ratio of 2:1, and the number of viable bacteria in the agent is not less than 1×10 8 CFU per gram.

5. The method for preparing a wetland substrate improvement material for carbon sequestration and sink enhancement according to claim 4, characterized in that: The preheating temperature of the granulator is above 130° C., the compression ratio of the granulator grinding disc is 5.1, and the particle diameter of the wetland soil improvement material is set to 6 mm.

6. The method for preparing a wetland soil improvement material for carbon sequestration and sink enhancement according to claim 5, characterized in that: In step S3, the continuous stirring process adopts a variable speed stirring method, first stirring at a speed of 200-300 rpm for 10 minutes, and then stirring at a speed of 50-100 rpm until the water is evenly distributed, so as to promote full fusion of the components.

7. A wetland soil improvement material for carbon sequestration and sink enhancement, characterized by: The improved material is prepared using the preparation method according to any one of claims 1 to 6, the pore size distribution of the improved material is uniform and covers between 1.5 and 12 nm, and the improved material includes the surface layer, middle layer and bottom layer of wetland soil.

8. The wetland soil improvement material for carbon sequestration and sink enhancement according to claim 7, characterized in that: The improvement material for the wetland soil surface layer consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite and microbial agents, wherein the sepiolite accounts for 12%-15% of the mass of the mixture and the microbial agents account for 2% of the mass of the mixture.

9. The wetland soil improvement material for carbon sequestration and sink enhancement according to claim 7, characterized in that: The improvement material for the middle layer of the wetland soil consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and nanocellulose, wherein the bentonite accounts for 10%-12% of the mass of the mixture and the nanocellulose accounts for 2%-3% of the mass of the mixture.

10. The wetland soil improvement material for carbon sequestration and sink enhancement according to claim 7, characterized in that: The improved material for the bottom layer of the wetland soil consists of a combination of reed biochar, acid-modified attapulgite, sepiolite, bentonite, microbial agents and graphene oxide, wherein the reed biochar accounts for 13%-14% of the mass of the mixture, and the graphene oxide accounts for 0.08%-0.12% of the mass of the mixture.

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