A method of low temperature oxygen activated regeneration of spent carbon

Abstract

The application discloses a method for regenerating waste carbon at low temperature and under oxygen activation, and aims at the problems of irreversible decline of adsorption performance of carbon-based materials after saturation, high energy consumption, large carbon loss and difficulty in directional performance recovery in traditional regeneration methods; the method comprises the following steps: preparing pretreated waste carbon, placing the waste carbon in a quartz tube of a tube furnace, and introducing a mixed gas composed of oxygen and inert gas, and then heating at a rate of 5-20 DEG C / min to 210-230 DEG C, and activating for 3-10 h, and finally cooling to room temperature under the atmosphere of inert gas to obtain regenerated carbon material. The mild and selective oxidation repair under the condition of low temperature and low oxygen can effectively dredge and repair the pore structure of waste carbon, directionally reconstruct the basic oxygen-containing active functional groups such as surface carbonyl and pyrone, significantly improve the adsorption capacity of regenerated carbon to perfluorinated compounds and the defluorination mineralization capacity, and the method has the advantages of simple process, low energy consumption, no generation of toxic and harmful by-products, easy industrialization and the like, and provides a reliable technical scheme for resource recycling and utilization of waste carbon adsorbent.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a method for low-temperature oxygen activation and regeneration of waste carbon. Background Technology

[0002] Activated carbon and other adsorbent materials play an irreplaceable role in the deep purification of water and waste gas as key media for environmental remediation. Their well-developed pore structure and high specific surface area enable them to efficiently capture and enrich various organic pollutants, achieving rapid phase transfer separation. However, the regeneration of materials after adsorption saturation is a global challenge: while surface pollutants can be removed through thermal desorption or solvent elution, the adsorption performance of the resulting "clean" materials often suffers significant and irreversible degradation. This is mainly attributed to the high-temperature thermal stress or chemical erosion during regeneration, leading to localized graphitization of the carbon skeleton, collapse of the microporous structure, decrease in specific surface area, and loss of key surface chemical functional groups, such as oxygen-containing active sites. This renders the materials unusable for direct recycling, essentially turning them into low-performance "waste carbon."

[0003] Currently, the disposal of such degraded materials faces a dual dilemma: direct disposal not only wastes resources but also incurs high solid waste treatment costs; while attempting to restore their performance involves traditional high-temperature activation processes typically exceeding 700°C, which, although capable of regenerating some pores through vigorous oxidation, suffer from significant energy consumption, severe carbon matrix burn-off (often exceeding 15%), and decreased mechanical strength after regeneration. More importantly, this non-selective high-temperature oxidation process indiscriminately destroys beneficial surface chemical structures, making it difficult to achieve efficient and targeted restoration of adsorption performance. Therefore, developing a regeneration technology that can gently and controllably repair the internal pore structure of materials and precisely regenerate their surface chemically active sites under relatively low-temperature conditions is an urgent practical need and has significant industrial value for promoting the closed-loop recycling of carbon materials and reducing the life-cycle cost of environmental governance. Summary of the Invention

[0004] The purpose of this invention is to provide a low-temperature oxygen activation regeneration method that is simple to operate, cost-controllable, and environmentally friendly. It addresses the common problems of severe degradation of adsorption performance of existing waste carbon materials after pollutant desorption, high energy consumption and large carbon loss in traditional regeneration methods. By precisely controlling the oxygen concentration under low-temperature conditions, the invention aims to repair the pore structure of waste carbon and rebuild its surface active functional groups, thereby efficiently restoring its adsorption performance and enabling multiple cycles of adsorbent recycling.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows: A method for low-temperature oxygen activation and regeneration of waste carbon, comprising, Waste carbon materials are pretreated to obtain pretreated waste carbon; The pretreated waste carbon is transferred to the quartz tube of a tubular furnace, and a mixture of oxygen and inert gas is continuously introduced into the quartz tube. The tubular furnace is heated to 210~230℃ and activated at a constant temperature for 3~10 hours. After the activation at a constant temperature, the heat input and oxygen supply to the tubular furnace are stopped, while the inert gas atmosphere is continuously introduced. The reaction system is then naturally cooled to room temperature to obtain the recycled carbon material.

[0006] This invention differs fundamentally from traditional wet oxidation at around 200℃ by employing a low-temperature gas-phase process within the 210-230℃ range, combined with a controllable gas-phase oxygen activation process that precisely controls low-concentration oxygen. This invention utilizes gentle gas-phase oxygen etching, free from liquid-phase solvent erosion and mass transfer limitations. It achieves selective gas-phase oxidation repair of waste carbon at significantly lower temperatures than traditional high-temperature thermal regeneration, drastically reducing energy consumption and overall operating costs. The pore structure of the treated regenerated carbon material is effectively unblocked and repaired, with more alkaline oxygen-containing functional groups, such as carbonyl C=O and pyranone structures, directionally constructed on the surface, significantly enhancing the adsorption capacity and activity for target pollutants. This process avoids the damage to the carbon skeleton caused by high-temperature thermal stress, preventing microporous structure collapse, localized graphitization of the carbon matrix, and decreased mechanical strength. It also minimizes carbon matrix burn-off, ensuring the structural integrity of the regenerated carbon and laying the foundation for efficient recovery of adsorption performance.

[0007] Preferably, the waste carbon material includes heat-treated waste carbon, which includes at least one of coal-based activated carbon, wood-based activated carbon, and biochar.

[0008] Preferably, the organic pollutants include one or more of perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, perfluoroether carboxylic acids, perfluoroether carboxylic acid sulfonic acids, fluorinated alcohols, and aqueous film-forming foam extinguishing agents.

[0009] Preferably, the inert gas includes nitrogen and / or argon.

[0010] Preferably, the volume ratio of oxygen to inert gas is 1~4:16~19.

[0011] Preferably, the flow rate of the mixed gas is 50~300 mL / min.

[0012] Preferably, the pretreatment includes a drying process.

[0013] Preferably, the drying temperature is 100~140℃.

[0014] Preferably, the drying process takes 12 to 24 hours.

[0015] The entire regeneration process is carried out in a closed system, using oxygen as the primary remediation agent. Precise control of low-concentration oxygen enables selective oxidation removal of pore blockages and surface adsorbates, unlike the non-selective and severe oxidation of the carbon matrix and adsorbates in traditional high-temperature processes. Therefore, this invention can gently etch and unblock the pore channels of waste carbon, effectively removing residual adsorbates and blockages within the channels, while also directionally rebuilding oxygen-containing active sites on the surface, significantly enhancing the specific interaction ability of the regenerated carbon with target pollutants. Furthermore, the precise action of low-concentration oxygen on non-carbon-based blockage components and surface site modification avoids excessive oxidation and loss of the carbon matrix. Simultaneously, no other chemical agents are required, ensuring no toxic or harmful byproducts are generated during the regeneration process, thus avoiding secondary pollution at the source and highlighting the advantages of green regeneration. It is a green regeneration technology; moreover, the process is simple, the conditions are mild, and it is easy to scale up, providing a reliable and industrially viable technical solution for the resource-based recycling of waste carbon adsorbents.

[0016] The present invention also discloses the application of recycled carbon materials in water treatment.

[0017] Preferably, water treatment includes enriching organic pollutants.

[0018] Preferably, the organic pollutants include one or more of perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, perfluoroether carboxylic acids, perfluoroether carboxylic acid sulfonic acids, fluorinated alcohols, and aqueous film-forming foam extinguishing agents.

[0019] This invention provides a method for preparing recycled carbon materials, comprising: Pretreated waste coal activated carbon that has failed heat treatment is dried at 100~140℃ for 12~24h to obtain pretreated waste carbon.

[0020] The pretreated waste carbon is transferred to a quartz boat and pushed into the quartz tube of a tubular furnace. A mixture of oxygen and inert gas is continuously introduced into the quartz tube, and the tubular furnace is heated to 210-230°C at a heating rate of 5-20°C / min. The furnace is then activated at a constant temperature of 210-230°C for 3-10 hours. After activation, a nitrogen atmosphere is continuously introduced, and the reaction system is naturally cooled to room temperature to obtain the recycled carbon material.

[0021] Preferably, the inert gas includes nitrogen and / or argon.

[0022] More preferably, the inert gas is nitrogen.

[0023] Preferably, the volume ratio of oxygen to inert gas is 1~4:16~19.

[0024] Preferably, the flow rate of the mixed gas is 50~300 mL / min.

[0025] This invention employs a controllable oxygen activation process centered on a low-temperature range of 210-230℃ to regenerate waste carbon into regenerated carbon adsorbent material. Therefore, it offers the following advantages: efficient restoration and enhancement of adsorption performance, increased defluorination rate, inhibition of the formation of toxic fluorine-containing intermediates, and integration of adsorption and harmless treatment. Thus, this invention is a simple, cost-effective, and efficient low-temperature oxygen activation regeneration method that simultaneously restores the adsorption performance of waste carbon and deeply mineralizes pollutants. It possesses significant industrial value and application prospects in the resource utilization of waste carbon in the water treatment field. Attached Figure Description

[0026] Figure 1 A schematic diagram of the temperature-programmed decomposition-mass spectrometry test results for recycled carbon materials.

[0027] Figure 2 This is a schematic diagram of the fitting results of the adsorption isotherm of the recycled carbon material. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] Example 1: Preparation of pretreated waste carbon: Heat-treated waste coal activated carbon that has failed to withstand heat treatment is dried at 120℃ for 18 hours to obtain pretreated waste carbon.

[0031] Preparation of recycled carbon material: Pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace. A mixture of nitrogen and oxygen was continuously introduced into the quartz tube, and the tube furnace was heated to 220°C at a heating rate of 10°C / min, and activated at 220°C for 5 hours. After activation, the nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain recycled carbon material. The volume ratio of oxygen to nitrogen was 1:19, and the flow rate of the mixed gas was 200 mL / min.

[0032] Comparative Example 1: Preparation of pretreated waste carbon: Heat-treated waste coal activated carbon that has failed to withstand heat treatment is dried at 120℃ for 18 hours to obtain pretreated waste carbon.

[0033] Preparation of comparative carbon material: Pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace; pure nitrogen gas was continuously introduced into the quartz tube, and the tube furnace was heated to 220℃ at a heating rate of 10℃ / min, and activated at 220℃ for 5 hours; after activation, the nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain the comparative carbon material. The nitrogen flow rate was 200 mL / min.

[0034] Comparative Example 2: Preparation of pretreated waste carbon: Heat-treated waste coal activated carbon that has failed to withstand heat treatment is dried at 120℃ for 18 hours to obtain pretreated waste carbon.

[0035] Preparation of comparative carbon material: Pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace. A mixture of nitrogen and oxygen was continuously introduced into the quartz tube, and the tube furnace was heated to 425℃ at a heating rate of 10℃ / min, and activated at 425℃ for 5 hours. After activation, the nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain the comparative carbon material. The volume ratio of oxygen to nitrogen was 1:19, and the flow rate of the mixed gas was 200 mL / min.

[0036] Comparative Example 3: Preparation of pretreated waste carbon: Heat-treated waste coal activated carbon that has failed to withstand heat treatment is dried at 120℃ for 18 hours to obtain pretreated waste carbon.

[0037] Preparation of comparative carbon material: Pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace; a mixture of nitrogen and oxygen was continuously introduced into the quartz tube, and the tube furnace was heated to 750°C at a heating rate of 10°C / min, and activated at 750°C for 1 hour; after activation, the nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain the comparative carbon material. The gas flow rate was 200 mL / min, and the other conditions were the same as in Example 1.

[0038] Comparative Example 4: Preparation of pretreated waste carbon: Heat-treated waste coal activated carbon that has failed to withstand heat treatment is dried at 120℃ for 18 hours to obtain pretreated waste carbon.

[0039] The pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace. A mixture of nitrogen and oxygen was continuously introduced into the quartz tube, and the tube furnace was heated to 850°C at a heating rate of 10°C / min. Activation was then carried out at 850°C for 1 hour. After activation, the nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain the comparative carbon material. The gas flow rate was 200 mL / min, and the other conditions were the same as in Example 1.

[0040] Comparative Example 5: Preparation of pretreated waste carbon: Waste coal-based activated carbon was dried at 120℃ for 18 hours to obtain pretreated waste carbon. The waste coal-based activated carbon was waste coal-based activated carbon that had undergone multiple cycles of adsorption of perfluorooctanoic acid and had reached adsorption saturation after thermal regeneration in a tubular furnace under nitrogen atmosphere. The thermal regeneration conditions were regeneration at 600℃ for 30 minutes.

[0041] Preparation of comparative carbon material: Pretreated waste carbon was transferred to a quartz boat and pushed into the quartz tube of a tube furnace. A mixture of nitrogen and oxygen was continuously introduced into the quartz tube, and the tube furnace was heated to 425℃ at a heating rate of 10℃ / min. Activation was carried out at 425℃ for 5 hours, followed by treatment at 850℃ for 1 hour. The nitrogen atmosphere was continuously introduced, and the reaction system was naturally cooled to room temperature to obtain the comparative carbon material. The volume ratio of oxygen to nitrogen was 1:19, and the flow rate of the mixed gas was 200 mL / min.

[0042] Experimental Example 1: Temperature-Programmed Decomposition of Regenerated Carbon Materials - Mass Spectrometry Testing.

[0043] Test samples: Regenerated carbon material prepared in Example 1 and pretreated waste carbon prepared in Example 1.

[0044] Test method: The recycled carbon material prepared in Example 1 and the pretreated waste carbon prepared in Example 1 were purged and pretreated under a helium atmosphere, and then heated to the target temperature at a programmed rate of 10℃ / min. At the same time, the signals of m / z=44 and m / z=28, i.e. CO2 and CO signals, were continuously monitored by mass spectrometry to analyze the gaseous products released by different functional groups during thermal decomposition.

[0045] The temperature-programmed decomposition-mass spectrometry test results of the recycled carbon material prepared by this invention are as follows: Figure 1As shown, compared with the pretreated waste carbon, the recycled carbon material treated with low-temperature oxygen activation in Example 1 showed a significant enhancement in the signal within the characteristic temperature range corresponding to CO release. This indicates that the content of basic oxygen-containing functional groups on the material surface, especially carbonyl C=O and pyranone structures, was significantly increased. This result confirms that in the low-temperature oxygen activation process provided by the present invention, under the conditions of strictly controlled temperature and low oxygen concentration, oxygen carried out mild and selective oxidation etching and reconstruction on the waste carbon surface. This process can not only directly form new oxygen-containing functional groups on the carbon material surface, but also promote the thermal transformation of some unstable acidic oxygen-containing functional groups, thereby generating more stable basic oxygen-containing functional groups, such as C=O and pyranone structures, thus achieving the directional optimization of the chemical properties of the waste carbon surface and the efficient recovery of adsorption activity.

[0046] Experimental Example 2: Test of the adsorption capacity of perfluorinated compounds in recycled carbon materials.

[0047] Test samples: Regenerated carbon material prepared in Example 1 and pretreated waste carbon prepared in Example 1.

[0048] Test Method: Perfluorooctanoic acid (PFOA) was dissolved in ultrapure water to prepare a PFOA solution with a concentration of 50 mg / L. The regenerated carbon materials prepared in each example and the comparative example, along with the pretreated waste carbon prepared in Example 1, were dispersed in ultrapure water to prepare carbon material dispersions with concentrations of 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, and 100 mg / L, respectively. The dispersions were ultrasonically vibrated until homogeneous before the adsorption test. PFOA adsorption was performed using the carbon material dispersions: the carbon material dispersion was added to a polypropylene bottle containing 50 mL of PFOA solution and vibrated at 200 rpm for 48 h in a constant-temperature shaker at 25°C. After standing, the supernatant from each conical flask was collected, filtered through a disposable syringe filter with a diameter of 0.22 μm, and the filtrate was collected. The concentration of PFOA in the solution was then determined using ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-MS / MS), and the adsorption equilibrium capacity q of PFOA was determined. e (mg / g) can be calculated using the following formula: q e =((C0-C e )×V) / m, where C0 (mg / L) is the initial concentration of the perfluorooctanoic acid solution, C e (mg / L) represents the equilibrium concentration of the perfluorooctanoic acid solution; V(L) is the volume of the solution, and m(g) is the mass of the carbon material; the Freundlich nonlinear isotherm model is used to fit the experimental data, and the equation is shown below: q e =K F ×C e 1 / n K F (mg / g) / (mg / L) 1 / nis the Freundlich adsorption capacity parameter, and n is the Freundlich exponent, which is related to the affinity of the adsorption energy distribution.

[0049] The adsorption isotherm fitting results of the recycled carbon material prepared in this invention are as follows: Figure 2 As shown in Table 1, the adsorption isotherm fitting parameters of the recycled carbon material prepared by this invention are shown in Table 1.

[0050] Table 1. Fitting parameters for the adsorption isotherm of the recycled carbon material

[0051] The adsorption isotherm fitting results of the carbon material prepared in Example 1 show that, compared with the pretreated waste carbon, the regenerated carbon material treated with low-temperature oxygen activation has a lower Freundlich model fitting parameter K. F The significant improvement indicates a substantial increase in adsorption capacity per unit area. The similar Freundlich exponents (n) of both materials demonstrate consistent high selectivity in their adsorption affinity distribution. This result confirms that the low-temperature oxygen activation regeneration method provided in this invention effectively repairs the pore structure of waste carbon while significantly enhancing its adsorption capacity for target pollutants. This enhancement effect can be attributed to the successful construction of more basic oxygen-containing functional groups, such as C=O and pyranone structures, on the carbon material surface under controllable low-temperature and low-oxygen conditions during the activation process, thereby strengthening the specific interaction between the carbon material and pollutant molecules. Therefore, the carbon material regenerated by this method not only restores its adsorption performance but also exhibits superior adsorption efficiency under high-concentration pollution conditions, making it of significant value for practical wastewater treatment applications.

[0052] Experimental Example 3: Thermal defluorination mineralization test of carbon material after adsorption of perfluorooctanoic acid.

[0053] Test samples: the recycled carbon material prepared in Example 1, the pretreated waste carbon prepared in Example 1, and the comparative carbon materials prepared in Comparative Examples 2-5.

[0054] Test method: After each carbon material was saturated with perfluorooctanoic acid (PFOA), it was dried at 40℃ for 24 h. The saturated carbon material was transferred to a quartz boat, and under the protection of an inert gas with a continuous flow rate of 200 mL / min, the temperature was increased from room temperature to 600℃ at a rate of 10℃ / min and held at that temperature for 30 min. The temperature was then lowered to room temperature to complete the subsequent pyrolysis and mineralization steps. The fluoride ion eluent from the pyrolysis system was obtained by eluting with ultrapure water. The fluoride ion concentration was then detected using an ion chromatograph. The defluorination rate can be calculated using the following formula: Defluorination rate (%) = (C... F - ×V F - ) / (0.6884×M)×100%, where C F- (mg / L) is the concentration of the eluent, V F - (L) is the volume of the eluent; M (mg) is the mass of perfluorooctanoic acid adsorbed on the activated carbon.

[0055] The defluorination rate of perfluorinated compounds by the carbon material prepared in this invention is shown in Table 2.

[0056] Table 2 Defluorination rate (%) of carbon materials for perfluorinated compounds

[0057] In Example 1, the regenerated carbon material after low-temperature oxygen activation treatment showed a significantly improved subsequent thermal defluorination and mineralization rate for perfluorinated and polyfluoroalkyl compounds compared to the pretreated waste carbon. This result directly confirms that the 210-230℃ low-temperature oxygen activation regeneration process provided by this invention can effectively restore the adsorption performance of waste carbon under mild and controllable conditions, while significantly enhancing its subsequent high-temperature pyrolysis and mineralization capacity for the loaded perfluorinated and polyfluoroalkyl compounds. Compared with the high-temperature activation comparisons, the regeneration effect under low-temperature conditions of this invention is generally superior. The high-temperature treatment groups generally cannot achieve the same level of defluorination and mineralization, which fully demonstrates that traditional high-temperature regeneration methods cause excessive oxidation and damage to the surface structure of carbon materials, making it impossible to achieve mild and controllable active site construction, thereby limiting the subsequent defluorination and mineralization efficiency. The significant increase in defluorination rate indicates that under precise activation conditions of low temperature and low oxygen concentration, the surface of carbon materials can be directionally modified and more alkaline oxygen-containing functional groups with high catalytic activity can be successfully constructed, mainly including carbonyl and pyranone structures. These stable and highly active sites can serve as core catalytic centers, effectively reducing the activation energy of carbon-fluorine bond breaking in the subsequent 600℃ pyrolysis mineralization step, enhancing the carbon-fluorine bond breaking and mineralization process, thereby promoting the complete decomposition of perfluorinated and polyfluoroalkyl compounds, while significantly inhibiting the generation and release of toxic fluorine-containing intermediates, reducing the risk of secondary pollution. Therefore, this method not only efficiently realizes the resource recycling of waste carbon, improving the service life and efficiency of the adsorbent, but also simultaneously enhances the harmless treatment efficiency of fluorine-containing pollutants in the regeneration process, achieving synergistic effects of material regeneration and in-depth pollutant treatment. It possesses outstanding technical advantages, environmental value, and broad industrial application prospects. The above-described embodiments and / or implementation methods are merely preferred embodiments and / or implementation methods for illustrating the implementation of the present invention, and are not intended to limit the implementation methods of the present invention in any way. Any person skilled in the art can make some modifications or alterations to other equivalent embodiments without departing from the scope of the technical means disclosed in the present invention, but these should still be considered as technologies or embodiments substantially the same as the present invention.

[0058] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A method for regenerating waste carbon using low-temperature oxygen activation, characterized in that: include, Pretreated waste carbon is obtained by pre-treating waste carbon materials. The pretreated waste carbon is transferred to the quartz tube of a tubular furnace, and a mixture of oxygen and inert gas is continuously introduced into the quartz tube. The tubular furnace is heated to 210~230℃ for isothermal activation. After the isothermal activation is completed, the heat input and oxygen supply to the tubular furnace are stopped, while the inert gas is continuously introduced. The reaction system is then naturally cooled to room temperature to obtain recycled carbon material.

2. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The waste carbon material includes heat-treated waste carbon, which includes at least one of coal-based activated carbon, wood-based activated carbon, and biochar. The organic pollutants include one or more of perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, perfluoroether carboxylic acids, perfluoroether carboxylic acid sulfonic acid, fluorinated alcohols, and aqueous film-forming foam extinguishing agents.

3. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The duration of the isothermal activation is 3 to 10 hours.

4. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The inert gas includes nitrogen and / or argon.

5. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 4, characterized in that: The volume ratio of oxygen to inert gas is 1~4:16~19.

6. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The flow rate of the mixed gas is 50~300 mL / min.

7. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The heating rate is 5~20℃ / min.

8. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 1, characterized in that: The pretreatment includes a drying process, wherein the drying temperature is 100~140℃.

9. The method for low-temperature oxygen activation and regeneration of waste carbon according to claim 8, characterized in that: The drying process lasts for 12 to 24 hours.

10. The application of the recycled carbon material prepared by the method according to any one of claims 1-9 in water treatment, characterized in that: The water treatment includes enriching organic pollutants, which include one or more of perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, perfluoroether carboxylic acids, perfluoroether carboxylic acid sulfonic acids, fluorinated alcohols, and aqueous film-forming foam extinguishing agents.

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