Fe-doped cork activated carbon as well as preparation method and application thereof

Abstract

The invention relates to the technical field of activated carbon materials, in particular to Fe-doped cork activated carbon and a preparation method and application thereof. The preparation method of the Fe-doped cork activated carbon comprises the following steps: (a) mixing cork charcoal and potassium ferrate in a solvent, and then drying to obtain a solid material; (b) carrying out heat treatment on the solid material in a protective atmosphere; in the step (b), the heat treatment comprises the step of heating and activating at the temperature of 600-900 DEG C for 0.5-3 hours. According to the preparation method, the potassium ferrate is adopted to treat the cork charcoal, so that the Fe-doped cork activated carbon which has a unique honeycomb characteristic, a high specific surface area, a good hierarchical porous structure, a high-density positive charge surface and a magnetic separation characteristic can be prepared, and a new way is provided for efficient adsorption of PFAS and separation and recovery of activated carbon.

Description

Technical Field

[0001] This application relates to the field of activated carbon materials technology, and in particular to an Fe-doped cork activated carbon, its preparation method, and its application. Background Technology

[0002] Perfluoroalkyl substances (PFAS) have garnered widespread attention due to their persistence in the environment, bioaccumulation, and pathogenicity to humans. In 2022, my country's GB 5749-2022 "Standards for Drinking Water Quality" set concentration limits of 80 ng / L for perfluorooctanoic acid (PFOA) and 40 ng / L for perfluorooctane sulfonic acid (PFOS). In 2024, the U.S. Environmental Protection Agency (EPA) issued a new mandatory health standard of 4 ng / L for PFOA and PFOS in drinking water. These extremely low environmental concentration limits and increasingly stringent regulatory requirements pose significant challenges to PFAS remediation efforts.

[0003] Activated carbon adsorption boasts advantages such as ease of operation, low cost, and no secondary pollution, making it considered the most promising and practical technology for breaking the permanent cycle of PFAS (phosphorus ions). However, the electrostatic repulsion between the generally negatively charged surface of activated carbon and anionic PFAS weakens the adsorption strength, resulting in purification effects that fail to meet current stringent drinking water hygiene standards. Furthermore, granular and powdered activated carbon often present challenges in separating and recovering from water. Exploring effective modification strategies to improve the adsorption and separation performance of activated carbon is crucial for its widespread application in PFAS pollution control. Summary of the Invention

[0004] In view of this, this application provides Fe-doped cork activated carbon, its preparation method, and its application.

[0005] Specifically, this application is implemented through the following technical solution:

[0006] The first aspect of this application provides a method for preparing Fe-doped cork activated carbon, comprising the following steps:

[0007] (a) Cork biochar and potassium ferrate were mixed in a solvent and then dried to obtain a solid material;

[0008] (b) The solid material is heat-treated under a protective atmosphere;

[0009] In step (b), the heat treatment includes: activating the product by heating at a temperature of 600–900°C for 0.5–3 hours.

[0010] In one embodiment, in step (a), the mass ratio of the cork biochar to the potassium ferrate is 1:(1-5).

[0011] In one embodiment, in step (a), the solvent comprises water.

[0012] In one embodiment, step (a), mixing the cork biochar with potassium ferrate in a solvent, comprises: adding the cork biochar to an aqueous solution of potassium ferrate and mixing. Further, the concentration of the aqueous solution of potassium ferrate is 1–10 g / L.

[0013] In one implementation, in step (a), the mixing time is 1 to 12 hours.

[0014] In one embodiment, the preparation of the cork biochar in step (a) comprises: pyrolyzing and carbonizing cork powder under a protective atmosphere to obtain the cork biochar. Further, the pyrolyzing and carbonizing comprises: holding at a temperature of 500–700°C for 0.5–3 hours.

[0015] In one embodiment, the cork powder has a size of 20 to 100 mesh.

[0016] The second aspect of this application provides Fe-doped cork activated carbon, which is prepared using the preparation method of Fe-doped cork activated carbon provided in the first aspect of this application.

[0017] In one embodiment, the specific surface area of ​​the Fe-doped cork activated carbon is 298–622 m². 2 / g.

[0018] In one embodiment, the surface Zeta potential of the Fe-doped cork activated carbon is +13.8 to +42.4 mV.

[0019] In one embodiment, the Fe-doped cork activated carbon has an adsorption capacity of 188–356 mg / g for perfluorooctanoic acid.

[0020] The third aspect of this application provides the application of Fe-doped cork activated carbon from the second aspect of this application in the adsorption of perfluoroalkyl substances in a water system.

[0021] In one embodiment, the method for adsorbing perfluoroalkyl substances includes: mixing and stirring the Fe-doped cork activated carbon with the water system to be treated, and then using a magnet to recover the Fe-doped cork activated carbon.

[0022] In one embodiment, the mixing and stirring process is carried out at a temperature of 20–60°C for a time of ≥1 min.

[0023] In one embodiment, the amount of Fe-doped cork activated carbon added is 0.1–0.5 g / L.

[0024] The method for preparing Fe-doped cork activated carbon provided in this application involves treating cork biochar with potassium ferrate to obtain Fe-doped cork activated carbon with unique honeycomb characteristics, high specific surface area, good hierarchical porous structure, high-density positively charged surface, and magnetic separation properties, providing a new approach for the efficient adsorption of PFAS and the separation and recovery of activated carbon. Attached Figure Description

[0025] Figure 1 This is a microscopic morphology image of the Fe-doped cork activated carbon prepared in Example 2 of this application;

[0026] Figure 2 These are nitrogen adsorption-desorption isotherms of Fe-doped cork activated carbon prepared in different embodiments of this application;

[0027] Figure 3 This is a graph showing the surface Zeta potential values ​​of Fe-doped cork activated carbon prepared in different embodiments of this application;

[0028] Figure 4 This is a comparison chart showing the adsorption and purification effects of Fe-doped cork activated carbon prepared in different embodiments of this application on PFOA.

[0029] Figure 5 This is a magnetic separation effect diagram of the Fe-doped cork activated carbon prepared in Example 2 of this application. Detailed Implementation

[0030] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0031] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0032] Fe doping of porous carbon materials introduces positively charged sites, thereby enhancing their electrostatic attraction to PFAS and facilitating magnetic separation of the porous carbon material. However, traditional Fe loading methods (such as impregnation and co-precipitation) often lead to Fe aggregation and poor site dispersion. Furthermore, excessive Fe loading can clog the pore structure of porous carbon and reduce its specific surface area, thus weakening the pore-filling effect of PFAS.

[0033] Based on this, this application provides a method for preparing Fe-doped cork activated carbon. By treating cork biochar with potassium ferrate, Fe-doped cork activated carbon with unique honeycomb characteristics, high specific surface area, good hierarchical porous structure, high-density positively charged surface and magnetic separation properties can be obtained, providing a new approach for the efficient adsorption of PFAS and the separation and recovery of activated carbon.

[0034] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this application below should be considered as the inventor's contributions to this application.

[0035] To facilitate understanding of this embodiment, the preparation method of Fe-doped cork activated carbon disclosed in this application will first be described in detail. The preparation method of Fe-doped cork activated carbon provided in this application includes the following steps:

[0036] (a) Cork biochar and potassium ferrate were mixed in a solvent and then dried to obtain a solid material;

[0037] (b) Solid materials are heat-treated under a protective atmosphere;

[0038] In step (b), the heat treatment includes: activating at a temperature of 600–900°C for 0.5–3 hours.

[0039] This application uses potassium ferrate to treat cork biochar, which introduces stable Fe species into the carbon matrix. Under the heat treatment conditions described in this application, potassium ferrate reacts with the carbon matrix to generate a well-developed porous structure. By introducing potassium ferrate, this application integrates Fe doping with the activation of activated carbon, improving not only the uniformity of Fe doping but also the degree of pore structure development in the activated carbon. Furthermore, the preparation process of the Fe-doped cork activated carbon in this application is simple and efficient.

[0040] In step (b), the heat treatment involves heating and activation at 600–900°C for 0.5–3 hours, allowing potassium ferrate to react under high-temperature conditions to generate KOH and Fe-based substances. KOH reacts with cork biochar to expand pores, and the Fe-based substances are uniformly incorporated into the carbon matrix. The temperature and time of the heat treatment are controlled within the above range to effectively balance the porosity, pore integrity, and Fe doping effect of the resulting activated carbon. In different embodiments, the temperature in step (b) can be 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, or any combination thereof; the activation time can be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or any combination thereof.

[0041] In one embodiment, the heat treatment in step (b) can be performed in a vacuum tube pyrolysis furnace, but is not limited to this. The heat treatment in step (b) is performed under a protective atmosphere, which includes, but is not limited to, at least one of nitrogen, argon, and helium. The gas flow rate of the protective atmosphere can be 50–300 mL / min, sufficient to ensure that the heat treatment process is carried out under a protective atmosphere.

[0042] In one embodiment, step (b) includes heating to 600–900°C at a heating rate of 2–10°C / min, and activating at 600–900°C for 0.5–3 hours. In different embodiments, the heating rate can be a range of 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, or any combination thereof, which further helps to ensure the overall structural stability of the solid material during heat treatment and the efficiency of the heat treatment.

[0043] In one embodiment, step (b) further includes: washing and drying the heat-treated solid material to obtain Fe-doped cork activated carbon. The washing may use distilled water and / or deionized water until the solid material is washed to neutrality.

[0044] In one embodiment, in step (a), the mass ratio of cork biochar to potassium ferrate is 1:(1-5), such as 1:1, 1:2, 1:3, 1:4, 1:5, or any combination thereof. When the amount of potassium ferrate is too high, excessive KOH is formed during heat treatment, which excessively corrodes the carbon matrix, causing micropores to merge into mesopores or macropores, and even causing structural collapse and a decrease in specific surface area. When the amount of potassium ferrate is too low, insufficient KOH is formed during heat treatment, resulting in insufficient pore expansion, and insufficient Fe doping, which easily clogs the pores. This application controls the mass ratio of cork biochar to potassium ferrate within the above range, which helps to balance the Fe doping content, doping uniformity, and pore development.

[0045] In one embodiment, in step (a), the solvent includes water. The preparation of the Fe-doped cork activated carbon of this application is carried out in an aqueous system, which is safe and environmentally friendly.

[0046] In one embodiment, step (a), mixing cork biochar and potassium ferrate in a solvent, comprises: adding cork biochar to an aqueous solution of potassium ferrate and mixing. Further, the concentration of the potassium ferrate aqueous solution is 1–10 g / L, such as 1 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, or any combination thereof, which further facilitates the dissolution of potassium ferrate and uniform mixing with the cork biochar. The preparation of the potassium ferrate aqueous solution includes, but is not limited to: adding potassium ferrate to water and mixing for 0.5–2 hours using methods such as magnetic stirring, ultrasonication, or constant-temperature oscillation.

[0047] In one embodiment, in step (a), the mixing time is 1 to 12 hours, such as a range of 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours or any combination thereof, to ensure that potassium ferrate and cork biochar are thoroughly mixed.

[0048] In one embodiment, in step (a), the mixing method includes at least one of magnetic stirring, ultrasonication, and isothermal oscillation.

[0049] In one embodiment, in step (a), the drying method includes at least one of natural air drying, forced air drying, vacuum drying, and freeze drying.

[0050] In one embodiment, the preparation of cork biochar in step (a) includes: pyrolyzing and carbonizing cork powder under a protective atmosphere to obtain cork biochar. Further, the pyrolysis and carbonization includes: holding at a temperature of 500–700°C for 0.5–3 hours. In different embodiments, the temperature during pyrolysis and carbonization can be a range of 500°C, 550°C, 600°C, 650°C, 700°C, or any combination thereof; the holding time can be a range of 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or any combination thereof.

[0051] In one embodiment, the preparation of cork biochar can be carried out in a vacuum tube pyrolysis furnace, but is not limited thereto. The pyrolysis and carbonization of the cork powder are conducted under a protective atmosphere, which includes, but is not limited to, at least one of nitrogen, argon, and helium. The gas flow rate of the protective atmosphere can be 50–300 mL / min, sufficient to ensure that the pyrolysis and carbonization process is carried out under a protective atmosphere.

[0052] In one embodiment, the pyrolysis carbonization in the preparation of cork biochar includes: heating to 500–700°C at a heating rate of 2–10°C / min, and holding at 500–700°C for 0.5–3 hours. In different embodiments, the heating rate can be a range of 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, or any combination thereof.

[0053] In one embodiment, the cork powder has a size of 20 to 100 mesh, for example, a range of 20 mesh, 40 mesh, 50 mesh, 60 mesh, 80 mesh, 100 mesh, or any combination thereof.

[0054] This application provides an optional method for preparing cork powder, which may include: washing cork raw materials with water to remove surface impurities, and then drying, pulverizing, and sieving to obtain cork powder. The cork raw materials include, but are not limited to, cork oak cork.

[0055] The second aspect of this application provides Fe-doped cork activated carbon, which is prepared using the preparation method of Fe-doped cork activated carbon provided in the first aspect of this application.

[0056] In one embodiment, the specific surface area of ​​the Fe-doped cork activated carbon is 298–622 m². 2 / g, such as 298m 2 / g、320m 2 / g, 350m 2 / g、380m 2 / g、400m 2 / g、450m2 / g、500m 2 / g、550m 2 / g、600m 2 / g、622m 2 / g or any combination thereof. This application uses potassium ferrate to treat cork biochar, combined with certain heat treatment conditions, to generate a well-developed porous structure while doping with Fe, significantly increasing the specific surface area of ​​the obtained Fe-doped cork activated carbon, while also possessing a hierarchical porous structure.

[0057] In one embodiment, the surface Zeta potential of the Fe-doped cork activated carbon is +13.8 to +42.4 mV, such as +13.8 mV, +15 mV, +20 mV, +25 mV, +30 mV, +35 mV, +40 mV, +42.4 mV, or any combination thereof. The Fe-doped cork activated carbon of this application has a high surface Zeta potential, which helps to improve the electrostatic interaction with PFAS, thereby increasing the adsorption capacity; furthermore, the high surface Zeta potential significantly reduces the agglomeration of activated carbon particles, exposes more adsorption sites, and improves the adsorption utilization rate of activated carbon.

[0058] In one embodiment, the adsorption capacity of Fe-doped cork activated carbon for perfluorooctanoic acid is 188–356 mg / g, such as 188 mg / g, 200 mg / g, 220 mg / g, 250 mg / g, 280 mg / g, 300 mg / g, 320 mg / g, 340 mg / g, 356 mg / g, or any combination thereof.

[0059] The third aspect of this application provides the application of Fe-doped cork activated carbon from the second aspect of this application in the adsorption of perfluoroalkyl substances in a water system.

[0060] In one embodiment, the perfluoroalkyl substance includes, but is not limited to, at least one of perfluorooctanoic acid and perfluorooctane sulfonic acid.

[0061] In one embodiment, the method for adsorbing perfluoroalkyl substances includes: mixing and stirring Fe-doped cork activated carbon with a water system to be treated, and then using a magnet to recover the Fe-doped cork activated carbon.

[0062] In one embodiment, the mixing and stirring process is carried out at a temperature of 20–60°C for a time of ≥1 min. The Fe-doped cork activated carbon of this application can be used to adsorb perfluorinated compounds in water systems at room temperature, and the residual concentration of perfluorinated alkyl substances can meet the requirements for drinking water within 60 min, making the operation simple and efficient.

[0063] In one embodiment, the amount of Fe-doped cork activated carbon added is 0.1 to 0.5 g / L, such as 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, or any combination thereof.

[0064] Example 1

[0065] This embodiment provides a method for preparing Fe-doped cork activated carbon, including the following steps:

[0066] (1) Cork raw material (cork oak cork) is washed with distilled water to remove surface impurities, and then placed in a forced-air drying oven to dry at 80°C. After crushing and sieving, 40-60 mesh cork powder is obtained for later use.

[0067] (2) Place the cork powder obtained in step (1) in a vacuum tube pyrolysis furnace, and raise the temperature from room temperature to 550°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. Hold the temperature at 550°C for 1 hour. After cooling to room temperature, take out the solid product, which is cork biochar.

[0068] (3) Add 0.2g of potassium ferrate to 50mL of distilled water and stir magnetically for 1h at room temperature to obtain a potassium ferrate solution. Then add 0.2g of the cork biochar obtained in step (2) to the potassium ferrate solution and stir magnetically for 8h at room temperature. Then place it in a forced-air drying oven and dry at 80℃ to obtain a solid material.

[0069] (4) The solid material obtained in step (3) is placed in a vacuum tube pyrolysis furnace and heated from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. The temperature is then maintained at 800°C for 2 hours. After cooling to room temperature, the solid product is removed, washed with distilled water until the pH is neutral, and dried at 80°C to obtain Fe-doped cork activated carbon, which is numbered CAC-Fe-1.

[0070] Example 2

[0071] This embodiment provides a method for preparing Fe-doped cork activated carbon, including the following steps:

[0072] (1) Cork raw material (cork oak cork) is washed with distilled water to remove surface impurities, and then placed in a forced-air drying oven to dry at 80°C. After crushing and sieving, 40-60 mesh cork powder is obtained for later use.

[0073] (2) Place the cork powder obtained in step (1) in a vacuum tube pyrolysis furnace, and raise the temperature from room temperature to 550°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. Hold the temperature at 550°C for 1 hour. After cooling to room temperature, take out the solid product, which is cork biochar.

[0074] (3) Add 0.2g of potassium ferrate to 50mL of distilled water and stir magnetically for 1h at room temperature to obtain potassium ferrate solution. Then add 0.1g of cork biochar obtained in step (2) to potassium ferrate solution and stir magnetically for 8h at room temperature. Then place it in a forced-air drying oven and dry at 80℃ to obtain solid material.

[0075] (4) The solid material obtained in step (3) is placed in a vacuum tube pyrolysis furnace and heated from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. The temperature is then maintained at 800°C for 2 hours. After cooling to room temperature, the solid product is removed, washed with distilled water until the pH is neutral, and dried at 80°C to obtain Fe-doped cork activated carbon, designated as CAC-Fe-2.

[0076] Example 3

[0077] This embodiment provides a method for preparing Fe-doped cork activated carbon, including the following steps:

[0078] (1) Cork raw material (cork oak cork) is washed with distilled water to remove surface impurities, and then placed in a forced-air drying oven to dry at 80°C. After crushing and sieving, 40-60 mesh cork powder is obtained for later use.

[0079] (2) Place the cork powder obtained in step (1) in a vacuum tube pyrolysis furnace, and raise the temperature from room temperature to 550°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. Hold the temperature at 550°C for 1 hour. After cooling to room temperature, take out the solid product, which is cork biochar.

[0080] (3) Add 0.2g of potassium ferrate to 50mL of distilled water and stir magnetically for 1h at room temperature to obtain a potassium ferrate solution. Then add 0.067g of the cork biochar obtained in step (2) to the potassium ferrate solution and stir magnetically for 8h at room temperature. Then place it in a forced-air drying oven and dry at 80℃ to obtain a solid material.

[0081] (4) The solid material obtained in step (3) is placed in a vacuum tube pyrolysis furnace and heated from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. The temperature is then maintained at 800°C for 2 hours. After cooling to room temperature, the solid product is removed, washed with distilled water until the pH is neutral, and dried at 80°C to obtain Fe-doped cork activated carbon, designated as CAC-Fe-3.

[0082] Example 4

[0083] This embodiment refers to the preparation method of Fe-doped cork activated carbon in Example 2, the only difference being that the heating activation temperature and time in step (4) are different.

[0084] Step (4) of this embodiment includes: placing the solid material obtained in step (3) in a vacuum tube pyrolysis furnace, raising the temperature from room temperature to 600°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min, and holding it at 600°C for 3 hours. After cooling to room temperature, the solid product is taken out, washed with distilled water to neutral pH, and dried at 80°C to obtain Fe-doped cork activated carbon.

[0085] Example 5

[0086] This embodiment refers to the preparation method of Fe-doped cork activated carbon in Example 2, the only difference being that the heating activation temperature and time in step (4) are different.

[0087] Step (4) of this embodiment includes: placing the solid material obtained in step (3) in a vacuum tube pyrolysis furnace, heating it from room temperature to 900°C at a heating rate of 10°C / min under a nitrogen atmosphere of 100 mL / min, and holding it at 900°C for 0.5 h. After cooling to room temperature, the solid product is taken out, washed with distilled water to neutral pH, and dried at 80°C to obtain Fe-doped cork activated carbon.

[0088] Comparative Example 1

[0089] Comparative Example 1 provides a method for preparing cork activated carbon, comprising the following steps:

[0090] (1) The cork raw material is washed with distilled water to remove surface impurities, and then placed in a forced-air drying oven to dry at 80°C. After crushing and sieving, 40-60 mesh cork powder is obtained for later use.

[0091] (2) Place the cork powder obtained in step (1) in a vacuum tube pyrolysis furnace, and raise the temperature from room temperature to 550°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. Hold the temperature at 550°C for 1 hour. After cooling to room temperature, take out the solid product, which is cork biochar.

[0092] (3) The cork biochar obtained in step (2) was placed in a vacuum tube pyrolysis furnace and heated from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere of 100 mL / min. The temperature was then maintained at 800°C for 2 hours. After cooling to room temperature, the solid product was removed, washed with distilled water until the pH was neutral, and dried at 80°C to obtain cork activated carbon, which was designated as CAC.

[0093] Experimental Example

[0094] The microstructure, specific surface area, and surface Zeta potential of Fe-doped cork activated carbon or cork activated carbon prepared in different embodiments and comparative examples of this application were tested. The test results are shown in […]. Figures 1-3 See Table 1. Figure 1 This is a microscopic morphology diagram of the Fe-doped cork activated carbon prepared in Example 2 of this application. As can be seen from the figure, the Fe-doped cork activated carbon prepared in this application has a unique honeycomb structure. Figure 2 The nitrogen adsorption-desorption isotherms are shown for Fe-doped cork activated carbon. Figure 3 The surface zeta potential of Fe-doped cork activated carbon is shown in the diagram.

[0095] The adsorption and purification effects of Fe-doped cork activated carbon or cork activated carbon prepared in different embodiments and comparative examples on PFOA were further tested. The test method included: taking 5 mg of the Fe-doped cork activated carbon or cork activated carbon sample to be tested, adding it to 20 mL of PFOA aqueous solution with an initial concentration of 1000 ng / L, and conducting adsorption tests in a constant temperature shaker at 25℃. The residual concentration of PFOA in the water was sampled and tested at different contact times. The test results are shown in […]. Figure 4 See Table 1.

[0096] Table 1 Test results of different activated carbons

[0097]

[0098] The test results above show that the Fe-doped cork activated carbon of this application possesses a unique honeycomb structure, high specific surface area, and a high-density positively charged surface. These excellent structural and surface chemical properties of the Fe-doped cork activated carbon of this application contribute to significantly improving its adsorption affinity for PFOA. The Fe-doped cork activated carbon prepared in the examples of this application exhibits a strong adsorption affinity for PFOA, including high adsorption capacity and fast adsorption kinetics, as well as excellent resistance to ion interference. After 60 minutes of adsorption, the residual concentration of PFOA in the water can be lower than 4 ng / L, meeting the concentration limits of PFOA in drinking water in multiple countries.

[0099] Take 5 mg of the Fe-doped cork activated carbon prepared in Example 2 and add it to 20 mL of water. Shake to evenly disperse the Fe-doped cork activated carbon in the water. Then place a magnet outside the container and perform magnetic separation as follows: Figure 5 As shown. From Figure 5 As can be seen from the present invention, the Fe-doped cork activated carbon of this embodiment has good magnetic separation performance and can be easily separated and recovered from the water system.

[0100] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing Fe-doped cork activated carbon, characterized in that, The steps include: (a) Cork biochar and potassium ferrate were mixed in a solvent and then dried to obtain a solid material; (b) The solid material is heat-treated under a protective atmosphere; In step (b), the heat treatment includes: activating the product by heating at a temperature of 600–900°C for 0.5–3 hours.

2. The preparation method according to claim 1, characterized in that, In step (a), the mass ratio of the cork biochar to the potassium ferrate is 1:(1-5).

3. The preparation method according to claim 1, characterized in that, In step (a), the solvent includes water.

4. The preparation method according to claim 1, characterized in that, In step (a), the mixing time is 1 to 12 hours.

5. The preparation method according to claim 1, characterized in that, The preparation of the cork biochar in step (a) includes: pyrolyzing and carbonizing cork powder under a protective atmosphere to obtain the cork biochar; The pyrolysis carbonization includes: holding at a temperature of 500–700°C for 0.5–3 hours.

6. An Fe-doped cork activated carbon, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

7. The Fe-doped cork activated carbon according to claim 6, characterized in that, It has at least one of the following characteristics: (1) The specific surface area of ​​the Fe-doped cork activated carbon is 298–622 m². 2 / g; (2) The surface Zeta potential of the Fe-doped cork activated carbon is +13.8 to +42.4 mV; (3) The Fe-doped cork activated carbon has an adsorption capacity of 188-356 mg / g for perfluorooctanoic acid.

8. The application of Fe-doped cork activated carbon in the adsorption of perfluoroalkyl substances in water systems, characterized in that, The Fe-doped cork activated carbon is the Fe-doped cork activated carbon as described in claim 6 or 7.

9. The application according to claim 8, characterized in that, The method for adsorbing perfluoroalkyl substances includes: mixing and stirring the Fe-doped cork activated carbon with the water system to be treated, and then using a magnet to recover the Fe-doped cork activated carbon.

10. The application according to claim 9, characterized in that, In the mixing and stirring process, the temperature is 20–60°C and the time is ≥1 min; The amount of Fe-doped cork activated carbon added is 0.1–0.5 g / L.

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