Iron-manganese modified granular activated carbon capable of being screened in compost and preparation method of iron-manganese modified granular activated carbon

Abstract

The invention belongs to the technical field of solid waste treatment and recycling, and relates to ferro-manganese modified granular activated carbon capable of being screened in compost and a preparation method of the ferro-manganese modified granular activated carbon capable of being screened in compost, and a ferro-manganese modified granular activated carbon material capable of being screened in compost is prepared by taking spherical granular activated carbon with the particle size of 2-4mm as a carrier; the iron-manganese oxide is loaded on the surface of the activated carbon through a coprecipitation method. Dipping the activated carbon in an iron-manganese mixed solution; adding alkali liquor to completely precipitate iron and manganese ions; and repeatedly cleaning the filtered product ethanol and deionized water respectively, and drying the prepared material. The prepared modified carbon can be used as a compost regulator to strengthen heavy metal passivation and antibiotic quenching effects and reduce the content of heavy metals and antibiotics in the organic fertilizer; the granular material is beneficial to separation and recovery of the modified carbon in the composting material, and is suitable for removing heavy metals and antibiotics in the composting process; the prepared FMAC is good in recovery effect, and when the water content of the organic fertilizer is 60% or below, the recovery rate can reach 95% or above.

Description

Technical Field

[0001] This invention belongs to the field of solid waste treatment and resource utilization technology, specifically relating to a remediation reagent with screening function and its preparation method, and particularly to an iron-manganese modified granular activated carbon material that can be screened and recovered in composting and its preparation method. Background Technology

[0002] With the intensive development of modern animal husbandry, the use of antibiotics and heavy metal additives (such as copper and zinc) in livestock and poultry farming continues to increase. Studies have shown that approximately 30-90% of feed antibiotics and 60-80% of heavy metal additives are excreted in their original form or as metabolites in livestock and poultry manure. If these pollutants enter the environment directly without proper treatment, they will pose a serious threat to ecosystems and human health through bioaccumulation in the food chain.

[0003] Composting technology, as the mainstream process for the resource utilization of livestock and poultry manure, has been widely used in the field of agricultural waste treatment due to its advantages such as low cost, simple operation, and effective elimination of pathogenic microorganisms. Although traditional composting processes can partially reduce antibiotic concentrations and decrease heavy metal activity through microbial degradation and physicochemical processes, its treatment effect has significant limitations. On the one hand, heavy metals in the composting process only undergo speciation transformation and are not completely removed; instead, a "relative concentration effect" occurs as organic matter degrades. On the other hand, the degradation efficiency of antibiotics is greatly affected by composting conditions, and some antibiotic residues may still retain biological activity.

[0004] To enhance pollutant removal during composting, researchers have developed various composting regulators. Based on their mechanisms of action, these regulators can be categorized as follows: 1. Adsorption regulators, such as activated carbon and bentonite, which fix pollutants through physical adsorption and ion exchange; 2. Chemical passivating agents, such as calcium magnesium phosphate and quicklime, which form insoluble precipitates with heavy metals; 3. Catalytic degradation agents, such as zero-valent iron and persulfate, which degrade organic pollutants through redox reactions; 4. Composite functional materials, such as modified biochar, which possess multiple mechanisms of action.

[0005] Chinese patent CN116637590A discloses a modified magnetic biochar, its preparation method, and its application in adsorbing heavy metals in compost. The method involves first loading active magnesium metal onto biochar, then loading amino and sulfonic acid groups to obtain preliminary modified biochar; subsequently, magnetic nano-zero-valent iron is loaded onto the preliminary modified biochar to obtain modified magnetic biochar. The prepared modified magnetic biochar material not only has strong adsorption capacity and abundant functional groups but also possesses magnetic adsorption force, enabling it to adsorb heavy metal pollutants in the solid phase of compost. Chinese patent CN115784202A also discloses a modified biochar coupled with microbial agents and its application. The modified biochar has abundant pores, a large specific surface area, and oxygen-containing groups, allowing it to react with heavy metals through a large number of negative charges, forming complexes with heavy metal ions. This passivates the heavy metals, causing them to transform from a highly reactive form to a less reactive form, thus reducing the content of the effective form of heavy metals. Chinese patent CN103819275A also discloses a method for regulating different forms of heavy metals in urban household compost using modified nano-carbon. This method modifies nano-carbon particles with a diameter of 20-70 nm before application, obtaining various modified nano-carbons. The addition of modified nano-carbon increases the content of residual heavy metals and promotes the transformation of heavy metals in compost from easily absorbed by plants to poorly absorbed forms, providing a basis for the application of modified nano-carbon in passivating heavy metals in waste compost. Chinese patent CN113880649A also discloses a method for preparing modified calcite to reduce antibiotics in compost. The modified calcite prepared by this method has a good adsorption effect on antibiotics in livestock and poultry manure compost and can create a neutral to slightly alkaline reaction micro-region, improving the efficiency of microorganisms and their extracellular degrading enzymes in removing antibiotics, thus achieving the goal of truly reducing antibiotics in compost. Chinese patent CN119874423A also discloses a method for removing antibiotics and resistance genes in aerobic composting of chicken manure. This method combines advanced persulfate oxidation technology with aerobic composting technology, adding potassium persulfate and zero-valent iron as aerobic composting additives. Zero-valent iron continuously activates potassium persulfate, generating persulfate radicals and hydroxyl radicals, promoting the removal of antibiotics and antibiotic resistance genes. It effectively removes high concentrations of oxytetracycline, sulfamethoxazole, and ciprofloxacin from chicken manure and significantly reduces the abundance of high-risk antibiotic resistance genes. Chinese patent CN115286443A also discloses a method for enhancing antibiotic degradation and heavy metal passivation in composting through high-temperature pretreatment combined with biochar. This involves adding composting additives to livestock and poultry manure to adjust the moisture content and carbon-nitrogen ratio, then performing high-temperature pretreatment, and finally adding biochar to the material for conventional composting.This method can shorten the composting cycle by about 20 days, achieve an antibiotic removal rate of over 99% in compost products, reduce the content of bioavailable heavy metals by over 50%, improve the safety of compost products, and reduce the risk of environmental pollution. This method can achieve rapid composting of livestock and poultry manure, with significant pollutant removal effect, strong sustainability, and potential for large-scale production.

[0006] However, existing regulator technologies still suffer from the following key drawbacks: 1. Material morphology limitations: Most existing regulators are micron-sized powders with low mechanical strength, easily breaking and pulverizing under the mechanical action of composting, such as turning and aeration; 2. Difficulty in separation and recycling: Compost products are usually directly returned to the field, making it difficult to effectively separate the added regulators, leading to the long-term accumulation of heavy metals and antibiotics in the soil; 3. Risk of secondary pollution: Some nanomaterials may enter the environment along with compost products, posing potential ecological risks. Therefore, there is an urgent need to develop a sieveable iron-manganese modified granular activated carbon for composting and its preparation method to effectively solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to address the heavy metal and antibiotic pollution during the composting process of poultry and livestock manure by providing an iron-manganese modified granular activated carbon with screening and recovery characteristics in composting, and its preparation method. This solves the problem of simultaneous removal of materials and pollutants, and the complete separation of heavy metals and antibiotics adsorbed and fixed by FMAC from the composting system. The prepared iron-manganese modified granular activated carbon material not only has excellent heavy metal passivation and antibiotic removal performance, but also can be efficiently recovered through physical screening after composting.

[0008] This invention is achieved through the following technical solution:

[0009] A type of iron-manganese modified granular activated carbon that can be screened in composting is made by loading iron-manganese oxides onto the surface of activated carbon using spherical granular activated carbon with a particle size of 2-4 mm as a carrier through a co-precipitation method.

[0010] A method for preparing sieveable iron-manganese modified granular activated carbon for composting includes the following steps:

[0011] A. Dissolve ferric chloride hexahydrate and manganese chloride tetrahydrate in 200 mL of deionized water in a certain proportion to prepare a mixed iron-manganese solution with a total molar ratio of 0.015 mol.

[0012] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution.

[0013] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 and the iron and manganese ions in the solution are completely precipitated. Shake for 2 hours under sealed conditions and then let stand for 24 hours.

[0014] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material.

[0015] Further, in step A, ferric chloride hexahydrate and manganese chloride tetrahydrate are dissolved in deionized water in ratios of 2:1, 1:1, and 1:2, respectively.

[0016] Further, in step B, the granular activated carbon is made from high-quality wood chips, coconut shells or coal matrix as raw materials, with the addition of binders, catalysts, etc., and is produced by crushing, mixing, pelletizing, drying, carbonizing and activating, with a specific surface area as high as 600-1000㎡ / g.

[0017] Further, in step B, the sealing condition refers to the use of a blue-capped bottle and a sealing film for double sealing.

[0018] Further, in step B, the oscillation method is shaking table oscillation, and the oscillation speed is 700-800 rpm.

[0019] Further, in step C, the alkaline solution is a 5 mol / L sodium hydroxide solution, the dropping rate is 4 mL / min, and the mixing method is shaking on a shaker at a speed of 700–800 rpm.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The iron-manganese modified granular activated carbon (FMAC) prepared by this invention uses high-mechanical-strength granular carbon as a carrier, successfully solving the industry problem of the difficulty in recycling traditional powdered additives. More importantly, this separation process achieves the simultaneous removal of "material-pollutant", enabling the complete separation of heavy metals and antibiotics adsorbed and fixed by FMAC from the composting system, rather than the simple passivation in traditional technologies;

[0022] 2. The FMAC prepared in this invention has an increased specific surface area and more adsorption sites due to the presence of iron-manganese oxides on its surface. The iron-manganese modification introduces oxygen-containing functional groups and FeO... x -MnO x These substances can enhance the complexation and co-precipitation effects between granular activated carbon and heavy metals. Simultaneously, iron-manganese oxides can enhance hydrogen bonding, π-π interactions, and surface coordination chelation between adsorbents and antibiotics; iron-manganese modified activated carbon can also generate active free radicals (·OH, ·O2). - Promotes the oxidative degradation of antibiotics;

[0023] 3. The FMAC prepared by this invention has high mechanical strength and good compressive strength, with a compressive strength of up to 4.014 MPa when broken.

[0024] 4. The FMAC prepared by this invention has good recovery effect. When the moisture content of organic fertilizer is 60% or less, the recovery rate can reach more than 95%. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of the synthesis process of the FMAC of the present invention;

[0027] Figure 2 shows scanning electron microscope images of the AC and FMAC of this invention; wherein, Figure 2a This is a scanning electron microscope image of AC. Figure 2b This is a scanning electron microscope image of FMAC;

[0028] Figure 3 The infrared spectra of AC and FMAC of this invention are shown below;

[0029] Figure 4 The diagram shows the recovery rates of AC and FMAC under different moisture contents according to the present invention.

[0030] Figure 5 This is a diagram showing the FMAC compressive strength of the present invention.

[0031] Figure 6 The diagram shows the removal of copper by the activated carbon and modified carbon of this invention.

[0032] Figure 7 This is a diagram showing the removal of zinc by the activated carbon and modified carbon of this invention;

[0033] Figure 8 This is a diagram illustrating the removal of tetracycline by activated carbon and modified carbon according to the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments:

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] It should be noted that similar reference numerals 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. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] This invention provides a sieveable iron-manganese modified granular activated carbon for composting and its preparation method. The material uses granular activated carbon with high mechanical strength and good compressive strength as a carrier, ensuring that the material maintains its structural integrity during composting and achieves efficient separation after composting. Simultaneously, the loaded iron-manganese oxides can synergistically enhance the removal efficiency of heavy metals and antibiotics, providing a practical technical solution to the problem of compost additive recovery.

[0038] This invention relates to a sieveable iron-manganese modified granular activated carbon for composting. Using granular activated carbon with a particle size of 2-4 mm as a carrier, iron-manganese oxides are loaded onto the surface of the activated carbon particles via a co-precipitation method. Because the carrier material is high-mechanical-strength granular carbon, separation of the material from the compost material is achieved. The presence of iron-manganese oxides on the material surface increases the specific surface area, adsorption sites, and oxygen-containing functional groups, thus promoting the degradation of pollutants.

[0039] The method for preparing the sieveable iron-manganese modified granular activated carbon in the above-mentioned compost includes the following steps:

[0040] A. Dissolve ferric chloride hexahydrate (FeCl3) and manganese chloride tetrahydrate (MnCl2·4H2O) in 200 mL of deionized water at ratios of 2:1, 1:1, and 1:2, respectively, to prepare a mixed iron-manganese solution (total molar ratio of iron to manganese is 0.015 mol).

[0041] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution.

[0042] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (so that the iron and manganese ions in the solution are completely precipitated), shake for 2 hours under sealed conditions, and then let stand for 24 hours.

[0043] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material.

[0044] Step B involves using high-quality sawdust, coconut shell, or coal matrix as raw materials, adding binders and catalysts, and then processing the granules through crushing, mixing, pelletizing, drying, carbonizing, and activation. The specific surface area can reach as high as 600-1000 m² / g. The sealing condition refers to a double seal using a blue-capped bottle and a sealing film. The vibration method is shaking on a shaker at a speed of 700-800 rpm.

[0045] Step C, the alkaline solution is a 5 mol / L sodium hydroxide solution, the dropping rate is 4 mL / min, and the mixing method is shaking on a shaker at a speed of 700-800 rpm.

[0046] The preparation processes of single-iron and single-manganese modified activated carbons FAC and MAC are consistent with those described above, with the iron-modified activated carbon requiring an iron solution and the manganese-modified activated carbon requiring a manganese solution.

[0047] Example 1

[0048] A. Dissolve 4.054g of ferric chloride hexahydrate (FeCl3) in 200mL of deionized water to prepare an iron solution;

[0049] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron solution.

[0050] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (so that the iron ions in the solution are completely precipitated), shake for 2 hours under sealed conditions, and then let stand for 24 hours.

[0051] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FAC material.

[0052] Example 2

[0053] A. Dissolve 2.969g of manganese chloride tetrahydrate (MnCl2·4H2O) in 200mL of deionized water to prepare a manganese solution;

[0054] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with manganese solution.

[0055] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (so that the iron and manganese ions in the solution are completely precipitated), shake for 2 hours under sealed conditions, and then let stand for 24 hours.

[0056] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain MAC material.

[0057] Example 3

[0058] A. Dissolve 2.703g of ferric chloride hexahydrate (FeCl3) and 0.989g of manganese chloride tetrahydrate (MnCl2·4H2O) in 200mL of deionized water to prepare a mixed iron-manganese solution;

[0059] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution.

[0060] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (so that the iron and manganese ions in the solution are completely precipitated), shake for 2 hours under sealed conditions, and then let stand for 24 hours.

[0061] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material (iron-manganese molar ratio of 2:1).

[0062] Example 4

[0063] A. Dissolve 2.027g of ferric chloride hexahydrate (FeCl3) and 1.484g of manganese chloride tetrahydrate (MnCl2·4H2O) in 200mL of deionized water to prepare a mixed iron-manganese solution.

[0064] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution.

[0065] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (the iron and manganese ions in the solution are completely precipitated, shake for 2 hours under sealed conditions and then let stand for 24 hours).

[0066] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material (iron-manganese molar ratio of 1:1).

[0067] Example 5

[0068] A. Dissolve 1.351g of ferric chloride hexahydrate (FeCl3) and 1.979g of manganese chloride tetrahydrate (MnCl2·4H2O) in 200mL of deionized water to prepare a mixed iron-manganese solution.

[0069] B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution.

[0070] C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 (so that the iron and manganese ions in the solution are completely precipitated), shake for 2 hours under sealed conditions, and then let stand for 24 hours.

[0071] D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material (iron-manganese molar ratio of 1:2).

[0072] like Figure 1 As shown, the preparation process of this invention involves impregnation followed by precipitation loading. Figure 2a As shown, the activated carbon surface is smooth. Figure 2b As shown, the surface of the iron-manganese modified activated carbon is rough and uneven, with iron-manganese oxides adhering to the surface of the activated carbon. Figure 3 As shown, FMAC contains a greater abundance of -COOH, -OH, CO, Fe-O, and Mn-O groups than AC. These functional groups not only enhance the surface activity of carbon materials and provide more adsorption sites, but also further improve the adsorption capacity of activated carbon. Figure 4 As shown, when the moisture content of the organic fertilizer is below 60%, the recovery rate of granular charcoal reaches over 95%, exhibiting high stability and facilitating screening and recovery after composting. Figure 5 As shown, FMAC exhibits a certain elastic deformation capacity when subjected to external pressure, and its compressive strength at break reaches 4.014 MPa, demonstrating the best compressive performance. Figure 6 The diagram shows the removal of available Cu from organic fertilizer by activated carbon and modified carbon. In the same time period, modified carbon is more effective than activated carbon in removal, and modified carbon with an iron-manganese molar ratio of 2:1 has the best removal effect. Figure 7 The diagram shows the removal of available Zn from organic fertilizer by activated carbon and modified carbon. In the same time period, modified carbon has a better removal effect than activated carbon, and modified carbon with an iron-manganese molar ratio of 2:1 has the best removal effect. Figure 8 The diagram shows the removal of tetracycline from organic fertilizer by activated carbon and modified carbon. In the same time period, modified carbon is more effective than activated carbon in removing tetracycline, and modified carbon with an iron-manganese molar ratio of 2:1 has the best removal effect.

[0073] This invention utilizes granular activated carbon with high mechanical strength and resistance to breakage as a carrier, allowing for screening and recovery during application. Secondly, loading iron-manganese oxides onto the surface of the activated carbon particles increases the specific surface area, adsorption sites, and oxygen-containing functional groups, promoting pollutant degradation. Compared to traditional regulators, this invention features separability and recyclability, carrying away pollutants from compost materials, reducing pollutant residues, and mitigating the risk of pollutant migration. The iron-manganese modified granular carbon prepared by this invention improves the passivation effect on heavy metals and the degradation rate of antibiotics, making it suitable as a remediation agent for heavy metal and antibiotic remediation in composting.

[0074] Note that the design of the digital prototype model, the parameter settings for each material, and the selection of the measuring plane described above are merely preferred embodiments and technical principles of the present invention. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A sieveable iron-manganese modified granular activated carbon for composting, characterized in that: It is made by using spherical activated carbon particles with a particle size of 2-4 mm as a carrier and loading iron and manganese oxides onto the surface of the activated carbon through a co-precipitation method.

2. A method for preparing sieveable iron-manganese modified granular activated carbon for composting, characterized in that, Includes the following steps: A. Dissolve ferric chloride hexahydrate and manganese chloride tetrahydrate in 200 mL of deionized water in a certain proportion to prepare a mixed iron-manganese solution with a total molar ratio of 0.015 mol. B. Weigh 3g of granular activated carbon AC and add it to the mixed solution obtained in step A. Shake for 1 hour under sealed conditions and let stand for 12 hours to ensure that the activated carbon is fully impregnated with the iron and manganese solution. C. Slowly add the alkaline solution dropwise to the solution obtained in step B, so that the pH of the solution is greater than 9 and the iron and manganese ions in the solution are completely precipitated. Shake for 2 hours under sealed conditions and then let stand for 24 hours. D. Filter the product in the solution obtained in step C, wash it repeatedly three times with ethanol and ultrapure water respectively, and then dry the washed product in a vacuum drying oven at 60°C to obtain FMAC material.

3. The method for preparing sieveable iron-manganese modified granular activated carbon for composting according to claim 2, characterized in that: Step A: Ferric chloride hexahydrate and manganese chloride tetrahydrate are dissolved in deionized water at ratios of 2:1, 1:1, and 1:2, respectively.

4. The method for preparing sieveable iron-manganese modified granular activated carbon for composting according to claim 2, characterized in that: Step B: The granular activated carbon is made from high-quality wood chips, coconut shells or coal matrix as raw materials, with the addition of binders, catalysts, etc., through crushing, mixing, pelletizing, drying, carbonizing and activation, and the specific surface area can be as high as 600-1000㎡ / g.

5. The method for preparing sieveable iron-manganese modified granular activated carbon for composting according to claim 2, characterized in that: Step B, the sealing condition refers to the use of a blue-capped bottle and a sealing film for double sealing.

6. The method for preparing sieveable iron-manganese modified granular activated carbon for composting according to claim 2, characterized in that: Step B, the oscillation method is shaking table oscillation, and the oscillation speed is 700-800 rpm.

7. The method for preparing sieveable iron-manganese modified granular activated carbon for composting according to claim 2, characterized in that: Step C, the alkaline solution is a 5 mol / L sodium hydroxide solution, the dropping rate is 4 mL / min, and the mixing method is shaking on a shaker at a speed of 700-800 rpm.

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