A nano-carbon material adsorbent, a preparation method and application thereof

Abstract

The application belongs to the technical field of water treatment, and particularly relates to a nano carbon material adsorbent, a preparation method and application thereof. The method comprises the following steps: 1) preparing a soft template solution; 2) mixing the soft template solution with deionized water, and adding a carbon source to prepare a precursor carbon material; 3) mixing the precursor carbon material with solid KOH, and then performing high-temperature carbonization; and 4) after the high-temperature carbonization is completed, naturally cooling to room temperature, and then performing water washing and drying on the cooled material to obtain the nano carbon material adsorbent. The application combines a specific soft template with subsequent KOH activation in depth, so that the KOH further etches and forms pores on the basis of the structure pre-constructed by the soft template, and a carbon material with high specific surface area, mesopore-micropore cooperation and rich oxygen-containing functional groups is prepared.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a nano-carbon material adsorbent, its preparation method, and its application. Background Technology

[0002] With the rapid development of the pharmaceutical and aquaculture industries, antibiotics are frequently detected in aquatic environments, becoming a new type of pollutant. Tetracycline antibiotics, in particular, pose ecological and environmental risks and potential threats to human health due to their stable chemical structure, resistance to degradation, and long-term persistence in water. Traditional biological treatment methods have limited removal rates for tetracyclines; therefore, developing cost-effective and efficient water treatment technologies is a pressing issue.

[0003] Adsorption is a simple, efficient, and flexible water treatment technology. Among them, carbon-based adsorbents, especially activated carbon, are widely used in water treatment technology due to their large specific surface area and good stability. However, traditional activated carbon materials have the following shortcomings: (1) Pore structure limitations: their structure is mostly microporous and unevenly distributed, which is insufficient for adsorbing pollutants with large molecular size; (2) Limited surface properties: the functional groups on the carbon surface that have not been specifically treated are single, and the selective adsorption capacity for specific pollutants is not strong; (3) High cost: traditional activated carbon is mainly derived from petrochemical or forest resources, which are difficult to regenerate and the preparation process is energy-intensive and expensive.

[0004] Currently, the preparation of high-performance porous materials for water treatment faces the following bottlenecks: traditional carbon materials prepared using soft templates and glucose have relatively inert surface chemistry and lack active sites for interaction with specific pollutants, resulting in limited adsorption selectivity and capacity. However, modifying carbon materials with KOH, which reacts with carbon at high temperatures, can etch abundant mesopores and micropores, significantly increasing specific surface area and porosity; simultaneously, it introduces functional groups, enhancing the material's hydrophilicity. This technology can significantly improve the adsorption efficiency of tetracycline in nanocarbon materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a nano-carbon material adsorbent, its preparation method, and its application.

[0006] The technical solution provided by this invention is as follows: A method for preparing a nano-carbon material adsorbent includes the following steps: 1) Preparation of soft template solution; 2) Mix the soft template solution obtained in step 1) with deionized water, add carbon source, stir until the solution is clear, then transfer the stirred solution into the reaction vessel, put it into the drying oven for heating, cool after the reaction is completed, centrifuge the cooled sample, wash with water and dry to obtain the precursor carbon material. 3) Mix the precursor carbon material obtained in step 2) with solid KOH, grind it into a fine powder, and evenly place it into a quartz boat. Place the quartz boat into a quartz tube, and then place the quartz tube into a vacuum atmosphere tube furnace. Inert gas is introduced to carry out high-temperature carbonization. 4) After high-temperature carbonization, the material is naturally cooled to room temperature. The cooled material is then washed with water and dried to obtain the nano-carbon material adsorbent.

[0007] In step 3) of the above high-temperature carbonization, KOH first melts at about 400℃ and penetrates into the precursor carbon material. When the temperature is raised to 450℃, KOH undergoes a preliminary redox reaction with carbon to produce K2CO3 and metallic potassium.

[0008] In step 3) of the above high-temperature carbonization, the temperature continues to rise to 700℃~800℃. K2CO3 decomposes at high temperature to produce K2O, which reacts with carbon to generate CO and CO2. At the same time, metallic potassium is inserted into the carbon layer, which violently etches the framework and forms a rich variety of mesopores and micropores.

[0009] In step 3) of the above high-temperature carbonization, the carbon layer migrates and reorganizes at high temperatures, ultimately forming a porous three-dimensional network structure with a high specific surface area. Products such as K, K₂CO₃, and K₂O generated during the reaction are removed in the subsequent water washing step.

[0010] In existing technologies, while soft template methods can construct ordered porous materials and KOH activation can create abundant voids and functional groups, they can also disrupt the ordered structure of the material. The above-mentioned technical solution deeply integrates a specific soft template with subsequent KOH activation, allowing KOH to further etch and create pores on the pre-constructed structure of the soft template. This produces carbon materials with high specific surface area, mesoporous-microporous synergy, and abundant oxygen-containing functional groups, solving the problem of traditional methods failing to balance activity and structure.

[0011] Specifically, step 1) includes the following steps: dissolving sodium oleate and block copolymer P123 in deionized water and stirring until the solution is pale yellow and clear to obtain a soft template solution, wherein the ratio of sodium oleate, block copolymer P123 and deionized water is 0.54-0.55g:0.65-0.66g:300mL, and the stirring time is 1.5-2.5h.

[0012] Specifically: the carbon source is glucose; the ratio of soft template solution, deionized water and glucose is 60mL:110-120mL:8-10g.

[0013] Specifically: Block copolymer P123 is poly(ethylene glycol)-block(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG, P123, Mn~5800), Aladdin Company.

[0014] Specifically, in step 2): the heating reaction temperature is 155-165℃, and the heating time is 7-9h.

[0015] Specifically, in step 2): the precursor carbon material is dried in a constant temperature oven at 65-75℃ for 6-24 hours.

[0016] Specifically, in step 2), the stirring time is 25-34 minutes.

[0017] Specifically, in step 2): during centrifugation, the centrifuge speed is 9000-11000 rpm and the time is 9-11 min.

[0018] Specifically, in step 2): wash with deionized water 2-4 times, and wash with ethanol once.

[0019] Specifically, in step 3): before high-temperature carbonization, nitrogen gas is first introduced for 15-25 minutes to purge the air. Under the nitrogen atmosphere, the first stage is: heating to 400-500℃ at 10℃ / min and holding for 50-70 minutes; the second stage is: heating to 700℃~800℃ at 5℃ / min and holding for 5-70 minutes; the third stage is: continuously introducing nitrogen gas and waiting for the furnace body temperature to cool naturally to room temperature before opening the tube furnace.

[0020] Specifically, in step 3): the second stage of the high-temperature carbonization process is heated to 700℃-800℃.

[0021] Specifically, in step 3), the mass ratio of carbon material to solid KOH is 1:1-3.

[0022] Specifically, in step 4): wash with deionized water until the pH of the material is neutral.

[0023] Specifically, in step 4): the washed carbon material is placed in a forced-air drying oven at a constant temperature of 65-75℃ and dried for 6-24 hours.

[0024] Preferably, in the above steps: In step 1), the mass of sodium oleate is 0.5475 g, the mass of block copolymer P123 is 0.6526 g, and the volume of deionized water is 300 mL.

[0025] In step 1), the mixing time of the mixed solution is 2 hours.

[0026] In step 2), the volume of the soft template solution is 60 mL, the volume of the deionized water is 114 mL, and the mass of glucose is 9 g.

[0027] In step 2), the mixing time of the mixture is 30 minutes.

[0028] In step 2), the heating reaction temperature is 160℃ and the heating time is 8h.

[0029] In step 2), the centrifuge speed is 10,000 rpm and the time is 10 minutes.

[0030] In step 2), the water wash is performed 3 times with deionized water and 1 time with ethanol.

[0031] In step 2), the precursor carbon material is dried overnight in a constant temperature oven at 70°C.

[0032] In step 3), the mass ratio of carbon material to solid KOH is 1:1, 1:2, or 1:3.

[0033] In step 3), before high-temperature carbonization, nitrogen gas is first introduced for 20 minutes to purge the air. Under nitrogen atmosphere, the first stage is as follows: heat to 450℃ at 10℃ / min and hold for 60 minutes; the second stage is as follows: heat to 700℃~800℃ at 5℃ / min and hold for 60 minutes; the third stage is as follows: continuously introduce nitrogen gas and wait for the furnace body temperature to cool naturally to room temperature before opening the tube furnace.

[0034] In step 3), the second stage of the high-temperature carbonization process is heated to 700℃, 750℃, and 800℃ respectively.

[0035] In step 4), the material is washed with deionized water until its pH is neutral.

[0036] In step 4), the washed carbon material is placed in a forced-air drying oven at 70°C overnight for drying. Furthermore, nitrogen doping can be applied to the nano-carbon material adsorbent.

[0037] The present invention also provides a nano-carbon material adsorbent prepared by the preparation method described above.

[0038] The nano-carbon material adsorbent of this invention possesses uniform mesopores and micropores with a high specific surface area, providing channels and adsorption sites for rapid diffusion of tetracycline molecules. Simultaneously, the hydroxyl and carbonyl functional groups on the material surface form strong hydrogen bonds and electrostatic interactions with the phenolic hydroxyl and amide groups in tetracycline. Its characteristics include high adsorption capacity and rapid adsorption of tetracycline, as well as good selectivity in complex water compositions. The present invention also provides the application of nano-carbon material adsorbents as adsorbents for tetracycline.

[0039] The beneficial effects of this invention are as follows: This invention uses inexpensive glucose as a carbon source, employs a specific soft template solution and KOH, and features a simple process that requires no complex equipment or stringent conditions. The method is low-cost, highly reproducible, and easily scaled up, overcoming the drawbacks of complex preparation processes and high costs associated with high-performance carbon nanomaterials, thus enabling the large-scale production of carbon nanomaterials for water treatment. Attached Figure Description

[0040] Figure 1 The images show SEM images of the carbon nanomaterials prepared at different activation temperatures in Example 1.

[0041] Figure 2 The image shows SEM images of the nano-carbon materials prepared with different carbon-base ratios in Example 2.

[0042] Figure 3 This is a SEM image of the nano-carbon material prepared by doping with N in Example 3.

[0043] Figure 4 The image shows a SEM image of the carbon nanomaterial prepared by vitamin C modification in Comparative Example 1. Detailed Implementation

[0044] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0045] Unless otherwise specified, the test methods used in the embodiments are conventional methods; unless otherwise specified, the materials and reagents used are commercially available.

[0046] Example 1 The mass ratio of carbon material to KOH is 1:2, and the high-temperature activation temperature is set to three temperature gradients: 700℃, 750℃, and 800℃.

[0047] (1) Mix 60 mL of soft template solution with 114 mL of deionized water, add 9 g of glucose, and stir for 30 min until completely dissolved. Then transfer the stirred solution to a 100 mL reaction vessel and react at 160 °C for 8 h. After the reaction is complete, cool, wash with water, and dry to obtain preliminary carbon material; (2) Mix the preliminary carbon material with solid KOH at a mass ratio of 1:2, grind it into a fine powder, and perform high-temperature carbonization in a tube furnace. First, introduce nitrogen into the tube furnace for 20 minutes and then purge the air. Under the nitrogen atmosphere, the first stage is: heat to 450°C at 10°C / min and hold for 60 minutes; the second stage is: heat to 700-800°C at 5°C / min and hold for 60 minutes; the third stage is: continuously introduce nitrogen and wait for the furnace body temperature to cool naturally to room temperature before opening the tube furnace. (3) After high-temperature carbonization, the material is naturally cooled to room temperature. The cooled material is washed with a large amount of deionized water until the pH is neutral, and then placed in a constant temperature air box to dry overnight to obtain a nano-carbon material adsorbent that can be used for water treatment.

[0048] The samples obtained by high-temperature carbonization at 700℃, 750℃, and 800℃ are respectively denoted as BC-K2-700, BC-K2-750, and BC-K2-800.

[0049] like Figure 1 The image shows SEM images of carbon nanomaterials prepared at different activation temperatures.

[0050] Example 2 The high-temperature activation temperature is 800℃, and the carbon-alkali ratio is set to three different mass ratios: 1:1, 1:2, and 1:3.

[0051] (1) A preliminary carbon material was prepared according to step (1) in Example 1. The preliminary carbon material was mixed with solid KOH at mass ratios of 1:1, 1:2, and 1:3, respectively, and ground into a fine powder. The powder was then carbonized at high temperature in a tube furnace. Nitrogen gas was first introduced into the tube furnace for 20 minutes, and the air was then purged. Under a nitrogen atmosphere, the temperature was raised to 450°C at 10°C / min and held for 60 minutes; then raised to 800°C at 5°C / min and held for 60 minutes. Nitrogen gas was continuously introduced, and the furnace was allowed to cool naturally to room temperature before the tube furnace was opened. (2) After high-temperature carbonization, the material is naturally cooled to room temperature. The cooled material is washed with a large amount of deionized water until the pH is neutral, and then placed in a constant temperature air box to dry overnight to obtain a nano-carbon material adsorbent that can be used for water treatment.

[0052] The nano-carbon materials prepared with different carbon-alkali ratios of 1:1, 1:2, and 1:3 are respectively denoted as: BC-K1-800, BC-K2-800, and BC-K3-800.

[0053] like Figure 2 The image shows SEM images of nano-carbon materials prepared with different carbon-base ratios.

[0054] Example 3 Referring to Examples 1 and 2, N element doping modification was performed using urea as the nitrogen source.

[0055] Carbon material and urea were dissolved in 100 mL of deionized water at a mass ratio of 1:1 and stirred for 4 h. The mixed solution was then dried in a constant temperature drying oven to obtain the material. The above mixed material was mixed with KOH at the optimal carbon-alkali ratio (carbon material: KOH = 1:3) determined in Example 2 and ground. High-temperature carbonization, washing, and drying were carried out according to the same heating program, holding time, and post-treatment method as step (2) in Example 2 to obtain a nano-carbon material adsorbent that can be used for water treatment, labeled as: NBC-K3-800. At the same time, the nano-carbon material BC-K3-800 without N doping in Example 2 was used as a comparative example.

[0056] like Figure 3 The image shown is a SEM image of the nitrogen-doped carbon nanomaterial.

[0057] Comparative Example 1 This comparative example demonstrates the surface functionalization modification of carbon materials using vitamin C without the use of KOH activation.

[0058] (1) Mix 60 mL of soft template solution with 40 mL of solution containing 3 g of glucose, stir for 30 min, transfer the mixture to a reaction vessel, and hydrothermally react at 160 °C for 8 h. After the reaction is complete, cool, wash with water, and dry to obtain preliminary carbon material; (2) The preliminary carbon material is carbonized at high temperature and placed in a tube furnace under nitrogen atmosphere. It is pre-calcined at 550°C for 4 hours, and then the temperature is increased from 550°C to 850°C at 5°C / min. It is calcined at this temperature for 1 hour to obtain the high-temperature activated nano-carbon material. (3) Dissolve 17.612g of vitamin C in 100mL of deionized water and stir magnetically for 3 hours to prepare a 1mol / L vitamin C solution. Then, mix 3.0g of carbon material with 6.0g of vitamin C solution and dry to obtain a nano-carbon material adsorbent that can be used for water treatment, labeled as: BC-K2-850-VC.

[0059] The adsorption performance of the nano-carbon materials prepared in Examples 1-3 and Comparative Example 1 was tested. The adsorption performance testing method is as follows: Take 50 mL of a 100 mg / L tetracycline solution into an Erlenmeyer flask, and add 10 mg of nano-carbon material to each flask. Seal the flask with sealing film and place it in a chilled water bath constant-temperature shaker at 165 rpm and 25 °C for 12 h of constant-temperature shaking adsorption. After shaking, aspirate the supernatant with a syringe, filter it through a 0.45 μm syringe filter, and store it. Determine the concentration of residual tetracycline in the filtrate using an ultraviolet-visible spectrophotometer.

[0060] like Figure 4The image shown is a SEM image of the carbon nanomaterial prepared by modifying vitamin C.

[0061] Test Example 1 Tetracycline adsorption experiments were conducted on the adsorbents prepared at 700℃, 750℃, and 800℃ in Example 1. The test results are as follows: BC-K2-700 has a monodisperse bowl-shaped structure with a relatively uniform overall morphology, a diameter of 150nm to 250nm, and a thickness of approximately 80nm.

[0062] The bowl-shaped structure of BC-K2-750 is destroyed, the particle outline loses support and collapses, and the structure is reorganized. Amorphous carbon shrinks and fuses to form a porous three-dimensional sheet network structure.

[0063] As the temperature rises further, the internal carbon layer of BC-K2-800 shrinks further, resulting in a much higher overall packing density than BC-K2-750, forming a denser porous three-dimensional sheet network structure.

[0064] The nano-carbon materials prepared at three different temperatures exhibit a transformation from a bowl-shaped structure to a porous three-dimensional layered network structure with increasing temperature. BC-K2-800 exhibits a denser porous three-dimensional layered network structure. This morphological change provides the nano-carbon materials with a large number of mesopores and micropores, significantly increasing the specific surface area of ​​the material. The "mesoporous-microporous" structure enables rapid and efficient adsorption kinetics. Simultaneously, the higher density indicates more effective adsorption sites per unit volume, which is beneficial for improving the adsorption rate.

[0065] The test results show that the equilibrium adsorption capacity gradually increases with increasing activation temperature. The adsorption capacity reaches its maximum value of 254.09 mg / g when the activation temperature is 800℃. This indicates that suitable high-temperature activation helps the nano-carbon material form a porous, three-dimensional, layered network structure with superior pore structure and higher packing density, resulting in higher adsorption capacity and adsorption rate, effectively enhancing the adsorption capacity of tetracycline.

[0066] Test Example 2 Tetracycline adsorption experiments were conducted on the carbon material and KOH mixture from Example 2 at ratios of 1:1, 1:2, and 1:3. The test results are as follows: BC-K1-800 has a monodisperse bowl-shaped structure with uniform overall morphology and size. The diameter of the carbon bowl is between 200nm and 250nm, and the thickness is about 80nm. After etching with KOH, the surface becomes rough, and some surfaces have a small number of depressions.

[0067] BC-K2-800 has a porous network structure. As the amount of KOH increases, the material is etched, the bowl-shaped structure is destroyed, and after the framework of the nano-carbon material is polymerized, a large number of mesopores and macropores are etched inside and stacked together.

[0068] BC-K3-800 has an internally open porous hollow network structure. The increased amount of KOH further increased the etching of the material, leading to large-scale structural collapse and reorganization of the carbon skeleton, ultimately forming a porous hollow network structure with a rough surface, rich in micropores, and an open interior.

[0069] Increasing the amount of KOH enhances the etching effect on the carbon material. Compared with the carbon nanomaterials prepared with carbon-base ratios of 1:1 and 1:2, the carbon nanomaterials prepared with a carbon-base ratio of 1:3 have the largest specific surface area, the most abundant micropores, and form an open porous hollow network structure. This allows tetracycline molecules to quickly enter and firmly bind to the micropore sites, while minimizing mass transfer resistance. Therefore, the equilibrium adsorption capacity increases with increasing carbon-base ratio.

[0070] Test results show that the adsorption performance is optimal when the carbon-to-base ratio is 1:3, with an adsorption capacity of 497.85 mg / g. This indicates that as the carbon-to-base ratio increases, the etching degree of KOH on the carbon material increases, generating more micropores and increasing the specific surface area. At the same time, some microporous structures are destroyed, leading to the formation of mesopores, which in turn increases the average pore size and pore volume, providing abundant physical adsorption sites for tetracycline molecules.

[0071] Test Example 3 For Example 3, the N-doped modified carbon nanomaterial was subjected to a high-temperature carbonization reaction at the optimal high-temperature activation temperature, using sample BC-K3-800 from Example 2 as a comparative example. The test results are as follows: NBC-K3-800 has a loose granular or flaky aggregate structure; BC-K3-800 has an internally open, porous, hollow bowl-shaped structure.

[0072] In NBC-K3-800, urea is used as the nitrogen source. Its thermal decomposition temperature is low, and the decomposition rate is relatively fast. When nitrogen is doped into carbon materials, the bond between nitrogen and carbon elements is relatively fragile, leading to structural collapse and recombination at high temperatures. This results in a loosely structured, irregular morphology of particles or sheet-like aggregates. Compared to KOH activation, nitrogen doping produces additional etching, generating more mesopores and micropores, increasing the specific surface area, and thus increasing effective adsorption sites, thereby improving the adsorption performance of tetracycline.

[0073] The test results show that the equilibrium adsorption capacity of the undoped N material is 497.85 mg / g, while the equilibrium adsorption capacity of the N-doped carbon nanomaterial increases to 845.21 mg / g, an increase of approximately 69.8%. This demonstrates that N doping significantly enhances the adsorption capacity of carbon nanomaterials for tetracycline.

[0074] Test Example 4 The test results of the carbon material modified with vitamin C in Comparative Example 1 are as follows: The nano-carbon material BC-K2-850-VC is a monodisperse bowl-shaped particle with a diameter ranging from 190 nm to 250 nm. It has a rough surface and a maximum adsorption capacity of 64.14 mg / g. The vitamin C-modified nano-carbon material forms hollow carbon bowls, and its unique microstructure and nanoscale size give it good adsorption performance for tetracycline.

[0075] After modification with vitamin C, BC-K2-850-VC, despite its smaller specific surface area, benefits from the introduction of oxygen-containing functional groups such as hydroxyl and carboxyl groups by vitamin C. This enhances the hydrogen bonding, electrostatic interactions, and "π-π" stacking effects with tetracycline, while maintaining a mesoporous and rough surface, thus achieving effective adsorption of tetracycline. Its adsorption mechanism is primarily based on surface chemical action, supplemented by physical pore filling.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a nano-carbon material adsorbent, characterized in that, Includes the following steps: 1) Preparation of soft template solution; 2) Mix the soft template solution obtained in step 1) with deionized water, add carbon source, stir until the solution is clear, then heat the stirred solution, cool after the reaction is complete, centrifuge the cooled sample, wash with water and dry to obtain precursor carbon material. 3) Mix the precursor carbon material obtained in step 2) with solid KOH, grind it into a fine powder, and evenly place it into a quartz boat. Place the quartz boat into a quartz tube, and then place the quartz tube into a vacuum atmosphere tube furnace. Inert gas is introduced to carry out high-temperature carbonization. 4) After high-temperature carbonization, the material is naturally cooled to room temperature. The cooled material is then washed with water and dried to obtain the nano-carbon material adsorbent.

2. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, Step 1) includes the following steps: dissolving sodium oleate and block copolymer P123 in deionized water and stirring until the solution is pale yellow and clear to obtain a soft template solution. The ratio of sodium oleate, block copolymer P123 and deionized water is 0.54-0.55g:0.65-0.66g:300mL, and the stirring time is 1.5-2.5h.

3. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 2): The carbon source is glucose; The ratio of soft template solution, deionized water, and glucose is 60 mL: 110-120 mL: 8-10 g.

4. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 2): The heating temperature is 155-165℃, and the time is 7-9 hours; The drying process is carried out in a constant temperature oven at 65-75℃ for 6-24 hours.

5. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 2): The stirring time is 25-34 minutes; During centrifugation, the centrifuge speed is 9000-11000 rpm, and the time is 9-11 minutes; Wash with deionized water 2-4 times, and with ethanol once.

6. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 3): Before high-temperature carbonization, nitrogen gas is introduced for 15-25 minutes to purge the air. The high-temperature carbonization is specifically as follows: In the nitrogen atmosphere, the first stage is carried out by heating to 400-500℃ at 10℃ / min and holding for 50-70 minutes; the second stage is carried out by heating to 700℃~800℃ at 5℃ / min and holding for 5-70 minutes; the third stage is carried out by continuously introducing nitrogen gas and waiting for the furnace body temperature to cool naturally to room temperature before opening the tube furnace. The second stage of the high-temperature carbonization process involves heating to 700℃-800℃.

7. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 3), the mass ratio of carbon material to solid KOH is 1:1-3.

8. The method for preparing the nano-carbon material adsorbent according to claim 1, characterized in that, In step 4): Wash with deionized water until the material reaches a neutral pH. After washing, place the carbon material in a forced-air drying oven at a constant temperature of 65-75℃ for 6-24 hours.

9. A nano-carbon material adsorbent prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the nano-carbon material adsorbent according to claim 9, characterized in that: As an adsorbent for tetracycline.

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