High-capacity coconut shell activated carbon adsorbent and preparation method thereof

Abstract

The invention belongs to the technical field of functional adsorption materials, and particularly relates to a high-capacity coconut shell activated carbon adsorbent and a preparation method thereof.The high-capacity coconut shell activated carbon adsorbent is prepared from, by weight, 80-90 parts of coconut shell carbon, 5-15 parts of mesoporous composite materials, 1-6 parts of aroma donors, 0.3-1.2 parts of sodium nitrite and 1 part of acid agents; the mesoporous composite material has a mesoporous mass transfer channel and a polarity trapping function, can improve diffusion conditions of organic molecules and enhance adsorption driving force to polar components such as aldehyde, ketone and the like, and has relatively high adsorption capacity and bed utilization efficiency to multi-component organic matters in petrochemical device gas at normal temperature and normal pressure; the method is suitable for high-efficiency adsorption and recovery of organic matters.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional adsorption materials, and particularly relates to a high-capacity coconut shell activated carbon adsorbent and a preparation method thereof. BACKGROUND

[0002] In the production process of petroleum chemical industry and related industries, device operation and material storage and transportation will produce device gas containing various organic components. Such device gas usually contains benzene series, olefins, and volatile organic compounds such as aldehydes and ketones. In order to meet the environmental protection emission requirements and realize the recovery of organic compounds, the adsorption method is widely used because of its mature process and mild operating conditions. Among them, coconut shell-based granular activated carbon has become one of the adsorbents commonly used in the industry due to its high specific surface area, developed microporous structure and good mechanical strength. However, the adsorption mechanism of the existing coconut shell-based activated carbon mainly depends on the physical adsorption of single microporous structure on organic molecules. Under the normal temperature and pressure conditions of actual petrochemical device gas, it is easy to be affected by mass transfer resistance and multi-component competitive adsorption, which shows that the bed layer penetration is in advance and the effective adsorption capacity is low. At the same time, the type of its surface functional groups is limited, and the adsorption driving force of polar organic compounds such as aldehydes and ketones is insufficient, and the water vapor competition further reduces the adsorption efficiency under the wet working condition. The existing technology attempts to improve the adsorption performance by increasing the specific surface area or simple chemical modification, but the capacity is limited under dynamic adsorption conditions, and the modification stability and engineering applicability still have deficiencies.

[0003] Therefore, it is urgent to develop a new type of adsorbent to break through the limitation of traditional single micropore adsorption mode by reasonable structure and interface design on the basis of maintaining the adsorption advantages of coconut shell carbon, to synergistically improve the mass transfer efficiency and the adsorption driving force of multi-component organic compounds, so as to meet the application requirements of efficient adsorption and recovery under actual working conditions. SUMMARY

[0004] In view of the above situation, the present application provides a high-capacity coconut shell activated carbon adsorbent and a preparation method thereof. The designed new adsorbent is mainly used to solve the problems of insufficient adsorption capacity, limited dynamic bed layer mass transfer and weak adsorption driving force of polar components in the adsorption and recovery process of multi-component organic compounds in petrochemical device gas under normal temperature and pressure conditions, break through the limitation of traditional single micropore adsorption mode of coconut shell activated carbon, and significantly improve the effective capacity and adaptation ability of the adsorbent under actual working conditions.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: The present application provides a high-capacity coconut shell activated carbon adsorbent, which comprises the following raw materials by weight: coconut shell carbon 80-90 parts, mesoporous composite material 5-15 parts, aromatic donor 1-6 parts, sodium nitrite 0.3-1.2 parts and acid agent 1 part.

[0006] Further, the aromatic donor is selected from any one of p-aminobenzenesulfonic acid, p-aminotoluene and p-aminobenzoic acid.

[0007] Further, the acidic agent is selected from any one of acetic acid, citric acid and sodium dihydrogen phosphate.

[0008] Further, the mesoporous composite material comprises the following raw materials: chloromethylstyrene, divinylbenzene, ferric chloride, 1-methylimidazole, 1,3-propane sultone and initiator.

[0009] Further, the mass ratio of the chloromethylstyrene, divinylbenzene, ferric chloride, 1-methylimidazole, 1,3-propane sultone and initiator is 42:18:6:8:7:1.

[0010] Further, the initiator is selected from AIBN (azobisisobutyronitrile) or BPO (benzoyl peroxide).

[0011] Further, the preparation method of the mesoporous composite material is as follows: S1: chloromethylstyrene and divinylbenzene are added into an organic solvent and mixed, an initiator is added, and a free radical polymerization reaction is carried out under a nitrogen atmosphere to generate cross-linked particles with high mechanical strength and a large number of benzyl chloride active sites, which provide reaction sites for subsequent hypercrosslinking to generate pore structures and introduce functional groups, and a polymer particle suspension is obtained; S2: ferric chloride is taken and added into the polymer particle suspension, heated and stirred to carry out Friedel-Crafts reaction, the benzyl chloride sites form -CH2- bridge structures with aromatic rings in the polymer particles under the catalysis of ferric chloride, further cross-linking is carried out, the polymer particles are promoted to form mesoporous structures, the precipitate is collected by filtration, and active mesoporous particles are obtained; S3: the active mesoporous particles, 1-methylimidazole and 1,3-propane sultone are dispersed in DMF (N,N-dimethylformamide) to form a sulfobetaine zwitterionic group, which has stronger dipole / hydrogen bond interaction with aldehydes / ketones and reduces the competitive interference of water vapor on the adsorption sites, and a composite material is obtained, the composite material is washed, dried and crushed to obtain a mesoporous composite material.

[0012] The application also provides a preparation method of a high-capacity coconut shell activated carbon adsorbent, and the specific steps are as follows: Step 1: coconut shell carbon and mesoporous composite material are mixed to promote the attachment and distribution of the mesoporous composite material powder on the surface and pores of the coconut shell carbon particles, and a compounded particle is obtained; Step 2: under ice bath conditions, an aromatic donor and sodium nitrite are dissolved together, an acidic agent is added, the pH is adjusted to be acidic, a highly reactive diazonium salt intermediate is formed, conditions are provided for subsequent combination with the surface of the coconut shell carbon in the compounded particle, and a diazonium salt solution is obtained. Step 3: The recombined particles are added to the diazonium salt solution, stirred and dispersed in an ice bath for 30 min, and then the temperature is raised to 30 DEG C to continue the reaction for 4 h, to obtain a reaction solution, which is filtered, and the precipitate is collected and washed and dried to obtain the high-capacity coconut shell activated carbon adsorbent.

[0013] The beneficial effects obtained by the present application are as follows: The high-capacity coconut shell activated carbon adsorbent prepared by the present application has a high specific surface area and a large micropore volume, and can adsorb a large amount of multi-component organic volatile substances in the gas of a petrochemical device. The mesoporous composite material independently synthesized by the present application provides a low-resistance diffusion channel and a long-acting adsorption interface for the adsorption process through the mesoporous network constructed by hypercrosslinking, significantly shortens the diffusion path of organic molecules from the gas phase to the micropore interior under the dynamic working condition of a fixed bed, and improves the availability of the micropore capacity, thereby overcoming the problems of insufficient utilization of pore space and insufficient adsorption of traditional coconut shell carbon in dynamic adsorption. Meanwhile, the sulfobetaine zwitterionic groups introduced on the surface of the mesoporous composite material can provide stronger dipole-dipole and hydrogen bond interactions for aldehydes / ketones and other oxygen-containing organic substances, improve the adsorption capacity under normal pressure or low pressure, and reduce the competitive interference of water vapor on the effective sites, so that the adsorption capacity is stable under high-humidity working conditions. In addition, the diazonium salt intermediate generated by the action of sodium nitrite and an acidic agent on the aromatic donor further improves the affinity for organic substances containing aromatic structures and olefin structures.

[0014] The multi-scale, multi-site, high-activity and high-capacity activated carbon adsorbent provided by the present application significantly improves the adsorption capacity and bed utilization efficiency of organic substances in the gas of a petrochemical device at room temperature and normal pressure compared with traditional adsorption materials, and has the characteristics of recyclability and cyclic utilization, and has good applicability and application value. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Adsorption isotherm investigation results of the high-capacity coconut shell activated carbon adsorbent prepared for Example 6; Figure 2 Specific surface area and total pore volume determination results of the high-capacity coconut shell activated carbon adsorbents prepared for Example 4, Example 6, Comparative Examples 1-2 and the blank group, and coconut shell carbon; Figure 3 Microscopic morphology characterization results of the high-capacity coconut shell activated carbon adsorbent prepared for Example 6 and coconut shell carbon; Figure 4 Adsorption capacity investigation results of the high-capacity coconut shell activated carbon adsorbents prepared for Comparative Example 1 and Example 6, and coconut shell carbon. DETAILED DESCRIPTION

[0016] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application; based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. In addition, any method and material similar or equivalent to those described herein can be used in the present application. The preferred methods and materials described herein are only for illustration and cannot limit the content of the present application.

[0018] In the following examples, unless otherwise specified, all are conventional methods; in the following examples, unless otherwise specified, the raw materials used are new materials purchased on the market; wherein, the particle size of the coconut shell charcoal used is 8-30 mesh (0.595-2.36 mm), the iodine value is 800 mg / g, the specific surface area is 844 m 2 / g, and the bulk density is 550 g / L; the ferric chloride used is anhydrous ferric chloride.

[0019] Example 1: The present embodiment provides a mesoporous composite material, which comprises the following raw materials by weight: chloromethylstyrene 42 parts, divinylbenzene 18 parts, ferric chloride 6 parts, 1-methylimidazole 8 parts, 1,3-propane sulfone 7 parts, and AIBN 1 part.

[0020] The preparation method of the mesoporous composite material is as follows: S1: 42 parts of chloromethylstyrene and 18 parts of divinylbenzene are added together into 180 parts of cyclohexane, 1 part of AIBN is added, and the free radical polymerization reaction is carried out under the conditions of nitrogen atmosphere, 70°C oil bath, and 400 rpm stirring for 30 min, to obtain a polymer particle suspension; S2: 6 parts of ferric chloride are added into the polymer particle suspension, and the crosslinking is further carried out under the conditions of 70°C and 400 rpm stirring for 6 h; the precipitate is collected by vacuum filtration, and then washed with anhydrous ethanol and deionized water in sequence, and dried, to obtain active mesoporous particles; S3: the active mesoporous particles, 8 parts of 1-methylimidazole and 7 parts of 1,3-propane sulfone are dispersed in 250 parts of DMF, and the stirring is carried out at 500 rpm for 8 h to form a sulfobetaine zwitterionic group; after the reaction is completed, the solid is collected by filtration, to obtain a composite material; the composite material is washed with anhydrous ethanol and deionized water in sequence, dried, ground and crushed, and then passed through a 200 mesh sieve, to obtain a mesoporous composite material.

[0021] Example 2: This example provides a mesoporous composite material, which comprises the following raw materials in parts by weight: chloromethylstyrene 42 parts, divinylbenzene 18 parts, iron chloride 6 parts, 1-methylimidazole 8 parts, 1,3-propane sultone 7 parts, and BPO 1 part.

[0022] The preparation method of the mesoporous composite material is as follows: S1: chloromethylstyrene 42 parts and divinylbenzene 18 parts are added together into 180 parts of ethyl acetate, and then BPO 1 part is added, and the mixture is stirred at 400 rpm under nitrogen atmosphere and 70°C oil bath reflux heating for 30 min to perform free radical polymerization reaction, thereby obtaining a polymer particle suspension; S2: iron chloride 6 parts is added into the polymer particle suspension, and the mixture is continuously stirred at 70°C and 400 rpm for 6 h to further perform crosslinking, and then the precipitate is collected by vacuum filtration, and the precipitate is sequentially washed with anhydrous ethanol and deionized water, and dried, thereby obtaining active mesoporous particles; S3: the active mesoporous particles, 1-methylimidazole 8 parts, and 1,3-propane sultone 7 parts are dispersed in 250 parts of DMF, and the mixture is stirred at 500 rpm for 8 h to form a sulfobetaine zwitterionic group, and then the solid is collected by filtration after the reaction is completed, thereby obtaining a composite material, and the composite material is sequentially washed with anhydrous ethanol and deionized water, dried, ground and crushed, and passed through a 200-mesh sieve, thereby obtaining a mesoporous composite material.

[0023] Example 3: This example provides a high-capacity coconut shell activated carbon adsorbent, which comprises the following raw materials in parts by weight: coconut shell carbon 80 parts, mesoporous composite material 15 parts, p-aminobenzenesulfonic acid 3 parts, sodium nitrite 1 part, and acetic acid 1 part.

[0024] The composition and preparation method of the mesoporous composite material are as described in Example 2.

[0025] This example also provides a preparation method of a high-capacity coconut shell activated carbon adsorbent, and the specific steps are as follows: Step 1: coconut shell carbon 80 parts and mesoporous composite material 15 parts are added into a drum mixer, and the mixture is mixed at a speed of 20 rpm for 25 min, thereby obtaining compounded particles; Step 2: under ice bath conditions, p-aminobenzenesulfonic acid 3 parts and sodium nitrite 1 part are dissolved in 120 parts of deionized water, and then acetic acid 1 part is added to adjust the pH to be acidic, and the pH is 3.46, and the reaction is continuously performed for 15 min to form a high-reactivity diazonium salt intermediate, thereby obtaining a diazonium salt solution; Step 3: The compounded particles were added to the diazonium salt solution, and dispersed by stirring at 200 rpm for 30 min under ice bath, and then the temperature was increased to 30°C for further reaction for 4 h to obtain a reaction solution. The reaction solution was filtered, and the precipitate was collected and washed with deionized water and anhydrous ethanol in sequence, and dried to obtain the high-capacity coconut shell activated carbon adsorbent.

[0026] Example 4: The present example provides a high-capacity coconut shell activated carbon adsorbent, which comprises the following raw materials by weight: coconut shell carbon 82.7 parts, mesoporous composite material 10 parts, p-aminotoluene 6 parts, sodium nitrite 0.3 parts, and citric acid 1 part.

[0027] The composition and preparation method of the mesoporous composite material are as described in Example 2.

[0028] The present example also provides a preparation method of the high-capacity coconut shell activated carbon adsorbent, and the specific steps are as follows: Step 1: Coconut shell carbon 82.7 parts and mesoporous composite material 10 parts were added to a drum mixer, and mixed at a speed of 20 rpm for 25 min to obtain compounded particles; Step 2: p-Aminotoluene 6 parts and sodium nitrite 0.3 parts were dissolved in 120 parts of 50% ethanol aqueous solution under ice bath, and then citric acid 1 part was added to adjust the pH to be acidic (pH 2.92), and the reaction was continued for 20 min to obtain a diazonium salt solution; Step 3: The compounded particles were added to the diazonium salt solution, and dispersed by stirring at 200 rpm for 30 min under ice bath, and then the temperature was increased to 30°C for further reaction for 4 h to obtain a reaction solution. The reaction solution was filtered, and the precipitate was collected and washed with deionized water and anhydrous ethanol in sequence, and dried to obtain the high-capacity coconut shell activated carbon adsorbent.

[0029] Example 5: The present example provides a high-capacity coconut shell activated carbon adsorbent, which comprises the following raw materials by weight: coconut shell carbon 90 parts, mesoporous composite material 5 parts, p-aminobenzoic acid 1 part, sodium nitrite 1.2 parts, and sodium dihydrogen phosphate 1 part.

[0030] The composition and preparation method of the mesoporous composite material are as described in Example 1.

[0031] The present example also provides a preparation method of the high-capacity coconut shell activated carbon adsorbent, and the specific steps are as follows: Step 1: Coconut shell carbon 90 parts and mesoporous composite material 5 parts were added to a drum mixer, and mixed at a speed of 20 rpm for 30 min to obtain compounded particles; Step 2: Dissolve p-aminobenzoic acid 1 part and sodium nitrite 1.2 parts in 120 parts of deionized water under ice bath condition, then add sodium dihydrogen phosphate 1 part, adjust pH to acidity, pH is 4.05, continue to react for 15 min to obtain a diazonium salt solution; Step 3: Add the compounded particles into the diazonium salt solution, disperse under ice bath and 200 rpm stirring for 30 min, then continue to react for 4 h at 30℃ to obtain a reaction solution, filter the reaction solution, collect the precipitate and wash with deionized water, and dry to obtain a high-capacity coconut shell activated carbon adsorbent.

[0032] Example 6: This example provides a high-capacity coconut shell activated carbon adsorbent, which comprises the following raw materials in parts by weight: coconut shell carbon 82 parts, mesoporous composite material 8 parts, p-aminobenzoic acid 3.2 parts, sodium nitrite 0.8 parts and citric acid 1 part.

[0033] The composition and preparation method of the mesoporous composite material are as described in Example 1.

[0034] This example also provides a preparation method of a high-capacity coconut shell activated carbon adsorbent, and the specific steps are as follows: Step 1: Put coconut shell carbon 82 parts and mesoporous composite material 8 parts into a drum mixer, mix at 20 rpm for 20 min to obtain compounded particles; Step 2: Dissolve p-aminobenzoic acid 3.2 parts and sodium nitrite 0.8 parts in 120 parts of deionized water under ice bath condition, then add citric acid 1 part, adjust pH to acidity, pH is 2.68, continue to react for 15 min to obtain a diazonium salt solution; Step 3: Add the compounded particles into the diazonium salt solution, disperse under ice bath and 200 rpm stirring for 30 min, then continue to react for 4 h at 30℃ to obtain a reaction solution, filter the reaction solution, collect the precipitate and wash with deionized water, and dry to obtain a high-capacity coconut shell activated carbon adsorbent.

[0035] Comparative Example 1 differs from Example 6 in that no mesoporous composite material is added, and the rest is the same as Example 6; Comparative Example 2 differs from Example 6 in that no p-aminobenzoic acid is added for modification, and the rest is the same as Example 6.

[0036] Pore structure characterization: 0.200 g of the adsorbents prepared in Example 4, Example 6, and Comparative Example 1-2, respectively, were taken as the samples to be tested, placed in a degassing station for vacuum degassing at 120°C for 4 h, transferred to a sample tube for sealing, and unmodified coconut shell charcoal was used as a blank group. A specific surface and pore size analyzer Micromeritics ASAP 2460 was used for detection. The test used a 77 K liquid nitrogen environment, and N2 adsorption-desorption isotherm collection was performed with a P / P0 range of 0.01-0.99. The N2 adsorption-desorption isotherm results of the adsorbent prepared in Example 6 are shown in Figure 1 ; the specific surface area was calculated by the BET method, the micropore volume was calculated by the t-plot method, and the total pore volume was converted from the adsorption amount at P / P0=0.99. After the test was completed, the specific surface area and total pore volume data were recorded, and the results are shown in Figure 2 .

[0037] Morphology observation: Unmodified coconut shell charcoal and the activated carbon adsorbent prepared in Example 6 were respectively fixed on conductive glue, placed in a sputtering instrument for gold sputtering, the film thickness was set to 10 nm to improve the conductivity and reduce the charging effect, and a scanning electron microscope Hitachi SU8010 was used for observation with an acceleration voltage of 5 kV and a working distance of 8 mm. The surface morphology image was collected, and the results are shown in Figure 3 .

[0038] Adsorption capacity investigation: The closed bottle static method was used to verify the adsorption equilibrium capacity. The unmodified coconut shell charcoal, the adsorbent samples prepared in Example 6 and Comparative Example 1 were cooled after being vacuum dried at 80°C for 6 h. The unmodified coconut shell charcoal was used as a blank group. 0.200 g of each sample was weighed and placed in a 250 mL headspace bottle and immediately sealed. A standard solution of 300 ppm benzene and 300 ppm acetone was injected into the headspace bottle to form the target initial concentration. The headspace bottle was placed in a constant temperature oscillator at 25°C and oscillated at 150 rpm for 12 h. After the equilibrium was reached, the headspace gas was sampled and quantitatively detected by gas chromatography with an FID detector. The chromatographic column was HP-5 (30 m x 0.32 mm x 0.25 μm), the injection port was 250°C, the column temperature program was 40°C for 2 min, then increased to 200°C at 10°C / min and maintained for 5 min, the carrier gas was nitrogen at 1.0 mL / min. The unit mass adsorption capacity (mg / g) was calculated according to the concentration difference before and after the equilibrium, and the results are shown in Figure 4 .

[0039] Figure 1 The results show that the adsorption isotherm of the adsorbent prepared in Example 6 is a composite type I isotherm, which is characterized by micropore (pore size <2 nm) gas adsorption characteristics, indicating that it has a rich micropore structure, and the hysteresis loop appears in the range of P / P0=0.5-0.99, indicating that the mesopore and macropore structure of the coconut shell charcoal still exists. The specific surface area is 1545 m 2 / g.

[0040] Figure 2 The results show that the specific surface area and the total pore volume of the activated carbon adsorbent prepared in Example 6 are higher, indicating that the adsorbent prepared by the present scheme has a high capacity and a high adsorption potential.

[0041] Figure 3 The results show that the surface of the activated carbon adsorbent prepared in Example 6 and the pore cavity are covered by dense particulate matter, indicating that the mesoporous composite material and the aromatic donor successfully modify the coconut shell carbon, and the specific surface area of the adsorbent is significantly improved.

[0042] Figure 4 The results show that the blank group coconut shell carbon has limited adsorption capacity for polar acetone and benzene, and the adsorbent prepared in Comparative Example 1 mainly relies on the modification of sulfanilic acid to improve the adsorption of coconut shell carbon, and the adsorption is improved. The high-capacity coconut activated carbon adsorbent prepared in Example 6 has a high specific surface area and rich polar and unsaturated bond adsorption sites, revealing a high active adsorption performance for volatile organic compounds in petrochemical device gas.

[0043] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

[0044] The above describes the present application and its embodiments, which are not restrictive, and the drawings only show one of the embodiments of the present application, and the actual application is not limited thereto. In summary, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, without creative design, similar ways and embodiments of the technical scheme should belong to the protection scope of the present application.

Claims

1. A high capacity coconut shell activated carbon adsorbent, characterized in that, The coconut shell activated carbon adsorbent comprises the following raw materials in parts by weight: coconut shell carbon 80-90 parts, mesoporous composite material 5-15 parts, aromatic donor 1-6 parts, sodium nitrite 0.3-1.2 parts and acid agent 1 part; The aromatic donor is selected from any one of p-aminobenzenesulfonic acid, p-aminotoluene and p-aminobenzoic acid; The mesoporous composite material comprises the following raw materials: chloromethylstyrene, divinylbenzene, ferric chloride, 1-methylimidazole, 1,3-propane sultone and initiator, and the mesoporous composite material is prepared by the following method: S1: chloromethylstyrene, divinylbenzene and initiator are reacted to obtain a polymer particle suspension; S2: ferric chloride is added to the polymer particle suspension to perform crosslinking reaction, and the precipitate is collected by filtration to obtain active mesoporous particles; S3: the active mesoporous particles are dispersed with 1-methylimidazole and 1,3-propane sultone to obtain a composite material, and the composite material is washed, dried and crushed to obtain the mesoporous composite material.

2. A high capacity coconut shell activated carbon adsorbent as claimed in claim 1, wherein, The mass ratio of the chloromethylstyrene, divinylbenzene, ferric chloride, 1-methylimidazole, 1,3-propane sultone and initiator is 42:18:6:8:7:

1.

3. A high capacity coconut shell activated carbon adsorbent as claimed in claim 2, wherein, The initiator is selected from AIBN or BPO.

4. A high capacity coconut shell activated carbon adsorbent as claimed in claim 1, wherein, The acid agent is selected from any one of acetic acid, citric acid and sodium dihydrogen phosphate.

5. A method for preparing a high-capacity coconut shell activated carbon adsorbent according to any one of claims 1-4, characterized in that, The specific steps are as follows: Step 1: coconut shell carbon and mesoporous composite material are mixed to obtain compounded particles; Step 2: the aromatic donor and sodium nitrite are dissolved together, and then the acid agent is added to obtain a diazonium salt solution; Step 3: the compounded particles are added to the diazonium salt solution to react, and a reaction liquid is obtained, the reaction liquid is filtered, and the precipitate is collected and washed and dried to obtain a high-capacity coconut shell activated carbon adsorbent.

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