Activated carbon and method for adsorbing and removing volatile organic compounds and mercury in flue gas

Abstract

The invention discloses activated carbon and a method for adsorbing and removing volatile organic compounds and mercury in flue gas. The method comprises the following steps: by taking agricultural wastes and a waste lithium ion battery positive electrode material as raw materials, soaking the waste lithium ion battery positive electrode material in an acid solution to extract high-activity metal components, and forming a mixed metal ion solution with a specific concentration; the method comprises the following steps: crushing agricultural wastes, and preliminarily carbonizing particles in an inert atmosphere to obtain a small amount of base carbon with specific pores; soaking the base carbon in a mixed metal ion solution to obtain base carbon loaded with metal components; the metal ion loaded base carbon is mixed with an alkaline activator, the pore structure of rich carbon is activated in an inert atmosphere, the distribution and existence form of metal components on the carbon surface are optimized, and the final active carbon with rich metal active sites and excellent adsorption performance is obtained. According to the invention, solid wastes with large volume at present are fully utilized as raw materials, the preparation method is simple, the energy consumption is low, and industrial large-scale production and application are fully guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of activated carbon preparation, in particular to activated carbon and a method for removing volatile organic matter and mercury in flue gas by adsorption. Background Art

[0002] Industrial processes such as coal combustion and waste incineration will produce a large amount of fine particles, NO x 、SO x , volatile organic compounds, heavy metals and other pollutants are important sources of air pollutants. In recent years, the increasingly stringent environmental protection policies have put forward higher requirements for the control of flue gas pollutants. High concentrations of fine particulate matter, NO x 、SO x Ultra-low emissions have been achieved through equipment innovation and process optimization. However, there is no separate equipment to control the emission of low-concentration volatile organic compounds and heavy metals. The volatile organic compounds and heavy metals in the flue gas, especially mercury, are highly toxic and can cause carcinogenesis, teratogenesis, and mutagenesis to the human body. At the same time, the volatile organic compounds and mercury emitted into the atmosphere will increase the PM in the atmosphere. 2.5 Concentration, induced photochemical smog, bring great pressure to the atmospheric environment. Many studies and practices have proved that flue gas injection adsorbent is an ideal method to remove low concentration mercury and volatile organic compounds. It does not change the original process, and does not require additional large equipment, which can effectively reduce the cost of flue gas treatment.

[0003] Activated carbon is an important adsorbent for adsorbing low-concentration pollutants. However, the combustion flue gas temperature is usually between 100 and 180°C, and the surface of the carbon material is a non-polar graphite surface, which is mainly physical adsorption. The interaction between pollutants and adsorption sites is weak, and the removal efficiency is low at higher flue gas temperatures. Therefore, the development of activated carbon with chemical adsorption sites has become the key to the efficient and synergistic removal of volatile organic compounds and mercury. Many literatures have reported the preparation methods of loaded metal porous carbon, but most of them use high-purity commercial metal salts as active components, which has high preparation costs and is not conducive to large-scale industrial production.

[0004] Low-cost raw materials are the key to large-scale preparation of activated carbon. Agricultural waste has a huge output in my country and is an important raw material for the preparation of activated carbon. The positive electrode materials of ternary lithium batteries contain Mn, Co, Ni, and Cu metal components. The current recycling process for a large number of waste ternary lithium battery positive electrode materials is complicated, with low metal recovery efficiency and low purity. Directly converting the highly active metal components of the positive electrode of ternary lithium batteries into metal active sites on the carbon surface will greatly improve the utilization efficiency of positive electrode metal materials and broaden the resource utilization path. Therefore, the development of a method for preparing activated carbon with highly active metal sites using agricultural waste and waste ternary lithium battery positive electrode materials as raw materials is of great significance for the synergistic removal of highly toxic volatile organic compounds and mercury in flue gas. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide an activated carbon and a method for adsorbing and removing volatile organic compounds and mercury in flue gas, which can be applied to the synergistic removal of highly toxic volatile organic compounds and mercury in hot flue gas, and solve the problems of single adsorption performance and low adsorption efficiency of activated carbon.

[0006] The present invention is implemented in this way. In a first aspect, the present invention provides an activated carbon suitable for synergistically adsorbing and removing volatile organic compounds and mercury in flue gas, wherein the activated carbon is prepared by the following method: The agricultural waste is crushed and then carbonized to obtain agricultural waste-based carbon with a small amount of pores; Removing lithium from the cathode material of waste ternary lithium batteries to obtain a mixed metal ion solution having metal components of Mn, Ni, Co and Cu; wherein the concentration ratio of Mn, Ni, Co and Cu in the mixed metal ion solution is (800-1500): (200-1000): (200-1000): (50-500), in units of mg / L; placing the agricultural waste-based carbon in the mixed metal ion solution for impregnation to obtain agricultural waste-based carbon loaded with metal components; The agricultural waste-based carbon loaded with metal components is mixed with an alkaline activator by ball milling, and further activated under an inert atmosphere to enrich the pore structure of the carbon, thereby obtaining activated carbon.

[0007] Preferably, the agricultural waste carbonization process comprises: The crushed agricultural waste was placed in a tubular furnace for carbonization. The carbonization temperature was 350~480 ℃, the carbonization time was 60~180 min, the heating rate was 5~15 ℃ / min, and the inert atmosphere flow rate was 200~400 mL / min.

[0008] Preferably, the lithium removal process of the waste ternary lithium battery positive electrode material includes: The positive electrode metal components are impregnated with acid, glucose is added to promote the leaching of metal ions, and then the metal ions in the leachate are precipitated by oxalic acid, the metal Li in the positive electrode material is separated, and the oxalate precipitate is dissolved by nitric acid; wherein, the impregnation temperature is 75~90 ℃, the impregnation time is 6~10 h, the acid concentration is 0.3~2 mol / L, the glucose addition amount is 0.1~0.5 g / g, and the oxalic acid addition amount is 30~45 g / L.

[0009] Preferably, during the lithium removal process of the waste ternary lithium battery positive electrode material, metal ion nitrate can also be added so that the concentration ratio of each metal ion in the final mixed metal ion solution satisfies the following: Mn, Ni, Co, Cu (800-1500): (200-1000): (200-1000): (50-500), in mg / L.

[0010] Preferably, the process for preparing agricultural waste-based carbon loaded with metal components comprises: The mass ratio of agricultural waste-based carbon to Mn, Ni, Co, and Cu metal ions in the mixed metal ion solution was 20:1~20:4, and the immersion time was 2~8 h.

[0011] Preferably, during the activation process, the mass ratio of the agricultural waste-based carbon loaded with metal components to the alkaline activator is 1:1 to 1:3.

[0012] Preferably, during the activation process, the alkaline activator is KOH, NaOH or KHCO3.

[0013] Preferably, during the activation process, the agricultural waste-based carbon loaded with metal components is ball-milled with an alkaline activator and then placed in a tubular furnace for activation. After activation, it is cooled to room temperature, the activation temperature is 650-800 °C, the activation time is 60-120 min, the heating rate is 5-15 °C / min, and the inert atmosphere flow rate is 200-400 mL / min.

[0014] Preferably, after the activation process is completed, post-treatment is required, and the post-treatment includes acid washing, water washing, and drying.

[0015] In a second aspect, the present invention provides a method for removing volatile organic compounds and mercury from flue gas by adsorption, which utilizes an adsorbent to synergistically adsorb and remove volatile organic compounds and mercury from flue gas; the adsorbent is the above-mentioned activated carbon.

[0016] The beneficial effects of the present invention are as follows: The present invention uses low-cost agricultural waste and waste lithium-ion battery positive electrode metal components as raw materials, couples the carbon source and metal source in the waste to prepare activated carbon with multi-metal active sites, which is used for removing highly toxic volatile organic matter and heavy metal mercury in flue gas. The preparation method is simple, the energy consumption is low, and large-scale industrial production is possible, which realizes efficient recycling of resources, reduces production costs, and reduces the potential harm of waste to the environment, and has good environmental and economic benefits. The present invention fully combines the characteristics of volatile organic compounds and mercury adsorbents. Based on their common adsorption sites, the highly active Mn, Ni, Co, and Cu metal components of the positive electrode of waste lithium batteries are converted into multi-metal oxides and solid solution sites on the surface of activated carbon to form multi-metal adsorption sites, thereby enhancing the diversity of adsorption sites on the surface of activated carbon. These metal sites can chemically adsorb volatile organic compounds and mercury in medium and high temperature environments (such as flue gas temperature range of 100-180°C), enhance the interaction between the adsorbent and the pollutants, and are conducive to the removal of low-concentration pollutants in hot flue gas.

[0017] The activated carbon prepared by the present invention can realize the synergistic removal of complex volatile organic compounds and mercury without changing the flue gas purification process, thereby reducing equipment investment and operating costs, and providing a new method for the efficient removal of low-concentration pollutants in flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a graph showing the N2 adsorption / desorption curve of the corn straw-based activated carbon prepared in an embodiment of the present invention.

[0020] Figure 2 This is the surface morphology of the corn straw-based activated carbon prepared in the embodiment of the present invention.

[0021] Figure 3 The figure is a comparison chart of the saturated adsorption amount of volatile organic compounds on commercial activated carbon and activated carbon prepared according to the embodiments of the present invention.

[0022] Figure 4 It is a comparison chart of the saturated adsorption amount of mercury on commercial activated carbon and activated carbon prepared in the examples of the present invention.

[0023] Figure 5 The present invention is a flow chart of the preparation method. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] From the background technology, it can be seen that how to use agricultural waste and waste ternary lithium battery positive electrode materials as raw materials to prepare activated carbon with highly active metal sites that can adsorb low-concentration pollutants and adapt to higher temperatures such as 100~180°C is the main technical problem to be solved by the present invention.

[0026] In this regard, this embodiment provides an activated carbon suitable for synergistically adsorbing and removing volatile organic compounds and mercury from flue gas, which has a rich pore structure, including a micro-mesoporous structure, and a large specific surface area. The rich pore structure provides more adsorption sites for volatile organic compounds and mercury, further improving the adsorption capacity. The activated carbon is prepared by the following method, using agricultural waste and waste lithium-ion battery positive electrode materials as raw materials, such as Figure 5 As shown, it includes the following processes:

[0027] Step 1: crushing agricultural waste and then carbonizing it to obtain agricultural waste-based carbon with a small amount of pores; Step 2: Remove lithium from the waste ternary lithium battery positive electrode material to obtain a mixed metal ion solution having Mn, Ni, Co, and Cu metal components; wherein the concentration ratio of Mn, Ni, Co, and Cu in the mixed metal ion solution is (800-1500): (200-1000): (200-1000): (50-500), in units of mg / L; Step 3, placing the agricultural waste-based carbon in the mixed metal ion solution for immersion to obtain the agricultural waste-based carbon loaded with metal components; Step 4: ball-milling the agricultural waste-based carbon loaded with metal components and an alkaline activator, and further activating the carbon under an inert atmosphere to enrich the pore structure of the carbon and obtain activated carbon.

[0028] In the above embodiments, the agricultural waste includes at least one of crop straw, wood chips, and fruit shells, the positive electrode material of the waste ternary lithium battery comes from the retired power battery of new energy vehicles, and the alkaline activator is KOH, NaOH or KHCO3.

[0029] The surface of the activated carbon prepared by the preparation method of the above embodiment is modified by highly active metals Mn, Ni, Co, and Cu, forming multi-metal adsorption sites, thereby enhancing the diversity of adsorption sites on the surface of the activated carbon, and can enhance the adsorption force on organic molecules and mercury in medium and high temperature environments, thereby improving the removal efficiency.

[0030] In one preferred embodiment, in step 1, the agricultural waste is cleaned, dried, ground, and sieved to obtain agricultural waste particles of 30 to 100 meshes.

[0031] In one preferred implementation manner, in step 1, agricultural waste particles are carbonized in a tubular furnace at a carbonization temperature of 350-480°C, a carbonization time of 60-180 min, a heating rate of 5-15°C / min, and an inert atmosphere flow rate of 200-400 mL / min; specifically, the inert atmosphere can be N2; the reasonable setting of these parameters is crucial to the carbonization effect of agricultural waste, and the appropriate temperature and time can cause the agricultural waste to undergo a pyrolysis reaction under the protection of an inert atmosphere, remove volatile components therein, and form agricultural waste-based carbon with a small amount of pores, thereby providing a good basic structure for subsequent loading of metal components and further activation.

[0032] In one preferred embodiment, in step 2, the waste ternary lithium-ion battery positive electrode material is acid-leached to remove lithium, and a mixed solution of Mn, Ni, Co, and Cu metal ions with a specific concentration is obtained; specifically, the positive electrode metal component is impregnated with citric acid or nitric acid, with a solid-liquid ratio of 15-25 g / L, glucose is added to promote the leaching of metal ions, the impregnation temperature is 75-90 ° C, the impregnation time is 6-10 h, the citric acid or nitric acid concentration is 0.3-2 mol / L, the glucose addition amount is 0.1-0.5 g / g, the metal ions in the leachate are precipitated with oxalic acid, the metal Li in the positive electrode material is separated, the oxalate precipitate is dissolved with nitric acid, and the oxalic acid addition amount is 30-45 g / L to obtain a mixed metal ion solution with Mn, Ni, Co, and Cu metal components, and the metal ion concentration in the mixed solution is adjusted to the following by concentration, dilution or addition of nitrate: Mn 2+ :800~1500 mg / L;Ni 2+ :200~1000 mg / L; Co 2+ :200~1000 mg / L; Cu 2+ : 50~500 mg / L.

[0033] In one preferred embodiment, in step 3, the agricultural waste-based carbon is immersed in a mixed metal ion solution, the mass ratio of the agricultural waste-based carbon to the Mn, Ni, Co, and Cu metal ions in the mixed metal ion solution is 20:1 to 20:4, and the mixture is immersed for 2 hours under stirring to ensure that the metal ions can be fully adsorbed onto the surface and pores of the agricultural waste-based carbon. Then, the metal ion mixture of the impregnated carbon is placed in a drying oven and evaporated at 80 to 95 °C to obtain carbon loaded with metal components.

[0034] In one preferred embodiment, the carbon loaded with metal components in step 4 is ball-milled and mixed with an alkaline activator, and the mass ratio of carbon to alkaline activator is 1:1~1:3. The two are fully mixed and evenly mixed by ball milling to create good conditions for the subsequent activation reaction. The ball-milled mixed material is placed in a tube furnace for activation, and cooled to room temperature after activation. The activation temperature is 650~800℃, the activation time is 60~120 min, the heating rate is 5~15℃ / min, and the inert atmosphere flow rate is 200~400 mL / min; specifically, the inert atmosphere can be N2. During the activation process, the alkaline activator and the base carbon loaded with metal components undergo a series of complex chemical reactions, which further enriches the pore structure of the carbon, optimizes the distribution and existence form of the metal components on the carbon surface, and makes the activated carbon have better adsorption performance. After the activation is completed, it is cooled to room temperature under an inert atmosphere to ensure the stability of the activated carbon structure.

[0035] In one preferred implementation manner, after step 4, the activated carbon may be subjected to post-treatment operations such as acid washing, water washing, and drying in sequence.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] As a specific implementation method, a method for preparing activated carbon suitable for synergistically adsorbing and removing volatile organic compounds and mercury in flue gas comprises the following steps: S1: Corn straw was selected as the basic raw material, washed with deionized water, dried at 105 °C for 12 h, ball-milled, and sieved to obtain corn straw particles of 30-100 mesh.

[0038] S2: 5 g of ternary lithium battery positive electrode material from retired new energy vehicles was selected as the raw material, 250 mL of 1.5 mol / L citric acid was added for impregnation, and 2 g of glucose was added to enhance the leaching efficiency. The metal ion leaching solution was obtained by leaching at 80 °C for 8 h.

[0039] S3: 10 g of oxalic acid was added to the metal ion leachate in step S2, the resulting precipitate was filtered, and then 100 mL of 0.5 mol / L nitric acid solution was added to dissolve it to obtain a mixed solution of Mn, Ni, Co, and Cu metal ions, and 150 mL of ultrapure water was added to dilute it to the following concentration: Mn 2+ :953.3 mg / L Ni 2+ :450.2 mg / L Co 2+ :368.1 mg / L Cu 2+:106.9 mg / L S4: 20 g of the corn stalk particles prepared in step S1 were placed in a tubular furnace for carbonization at a carbonization temperature of 400°C, a carbonization time of 90 min, a heating rate of 5°C / min, and a N2 flow rate of 300 mL / min.

[0040] S5: placing the carbonyl obtained in step S4 into the metal ion mixed solution obtained in step S3, with the mass ratio of carbonyl to metal ions being 20:1, stirring and impregnating for 2 h, placing in a drying oven, and evaporating at 90 °C for 24 h to obtain carbonyl loaded with metal components; S6: Under N2 atmosphere, the metal component-loaded carbon obtained in step S5 is ball-milled with KOH, with a mass ratio of carbon to KOH of 1:2, and placed in a tubular furnace for high-temperature activation. The activation temperature is 750°C, the heating rate is 10°C / min, the activation time is 60 min, and the N2 flow rate is 300 mL / min. After the activation, it is cooled to room temperature under N2 atmosphere.

[0041] S7: The corn straw-based activated carbon obtained in step S6 is placed in a 1 mol / L hydrochloric acid solution for washing, and when it is close to neutral, it is washed three times with ultrapure water, the washing liquid is neutral, and dried in a drying oven at 110°C for 24 h to obtain the final activated carbon loaded with metal components.

[0042] The N2 adsorption-desorption isotherms and pore structure parameters of the prepared corn straw-based activated carbon are shown in Figure 1 As shown in Table 1, the activated carbon has a rich pore structure, a micro-mesoporous structure, and a large specific surface area. Figure 2 As shown, the surface has different pore structures and there are loaded metal components, but there is no clogging of the pore size.

[0043] Table 1 Pore structure parameters of corn straw-based activated carbon

[0044] Performance test: The corn straw-based activated carbon prepared in the above embodiment was tested for its adsorption performance of volatile organic compounds and mercury, with para-xylene being used as the target volatile organic compound.

[0045] (1) Single component adsorption performance test: The adsorption performance of p-xylene and mercury on corn straw-based activated carbon was tested in a fixed bed adsorption device, with N2 as the balance gas; the fixed bed reactor had an inner diameter of 8 mm and a length of 300 mm; The adsorption conditions of p-xylene are as follows: concentration 100~110 mg / m 3; Adsorption temperature 120 ℃; total gas volume 1 L / min; activated carbon dosage 40 mg. The adsorption breakthrough curve was detected using a portable volatile organic compound detector.

[0046] Mercury adsorption conditions are as follows: concentration 50~60 μg / m 3 ; Adsorption temperature 120 ℃; Total gas volume 1 L / min; Corn straw-based activated carbon dosage: 40 mg. The adsorption breakthrough curve was tested using a portable mercury analyzer.

[0047] (2) Co-adsorption performance test: The co-adsorption performance of p-xylene and mercury on corn straw-based activated carbon was tested in a fixed bed adsorption device, with N2 as the balance gas; the fixed bed reactor had an inner diameter of 8 mm and a length of 300 mm; Adsorption conditions are as follows: p-xylene concentration 100~110 mg / m 3 ; Mercury concentration 50~60 μg / m 3 ; Adsorption temperature 120℃; total gas volume 1 L / min; activated carbon dosage 40 mg. The adsorption breakthrough curves were tested using a portable volatile organic compound detector and a portable mercury analyzer.

[0048] (3) The adsorption breakthrough curves were integrated to calculate the saturated adsorption amounts of p-xylene and mercury on corn straw-based activated carbon.

[0049] (4) In order to reflect the adsorption performance of the prepared activated carbon, conventional commercial activated carbon was selected as a comparison. The adsorption performance of xylene and mercury was tested under the same conditions. The pore structure parameters of the commercial activated carbon are shown in Table 2. The adsorption characteristics of xylene and mercury are shown in Table 2. Figure 3 , Figure 4 As shown. Under single-component adsorption conditions, the adsorption capacity of the corn straw-based activated carbon of the present invention for volatile organic compounds and mercury is 180.9 mg / g and 396.5 μg / g, respectively, which are 3.2 times and 9.8 times the adsorption capacity of commercial activated carbon, respectively. In an environment where volatile organic compounds and mercury coexist, the adsorption capacity of the corn straw-based activated carbon of the present invention for p-xylene and mercury is only reduced by 5.1% and 5.3%, respectively, while the adsorption performance of commercial activated carbon is reduced by 19.5% and 36.3%, respectively. Activated carbon loaded with multiple metal sites exhibits excellent synergistic adsorption and removal capabilities for low-concentration volatile organic compounds and mercury, and has good application prospects.

[0050] Table 2 Pore structure parameters of commercial activated carbon

[0051] Therefore, the activated carbon prepared by the present invention can achieve the synergistic removal of complex volatile organic compounds and mercury without changing the flue gas purification process. Compared with the traditional method, there is no need to set up removal equipment for volatile organic compounds and mercury separately, avoiding the problems of complex process and large equipment investment, effectively reducing equipment investment and operating costs, and providing a simple, economical and effective new method for the efficient removal of low-concentration pollutants in flue gas, which has broad application prospects.

[0052] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An activated carbon suitable for synergistically adsorbing and removing volatile organic compounds and mercury from flue gas, characterized in that: The activated carbon is prepared by the following method: The agricultural waste is crushed and then carbonized to obtain agricultural waste-based carbon with a small amount of pores; Removing lithium from the cathode material of waste ternary lithium batteries to obtain a mixed metal ion solution having metal components of Mn, Ni, Co and Cu; wherein the concentration ratio of Mn, Ni, Co and Cu in the mixed metal ion solution is (800-1500): (200-1000): (200-1000): (50-500), in units of mg / L; placing the agricultural waste-based carbon in the mixed metal ion solution for impregnation to obtain the agricultural waste-based carbon loaded with metal components; The agricultural waste-based carbon loaded with metal components is mixed with an alkaline activator by ball milling, and further activated under an inert atmosphere to enrich the pore structure of the carbon, thereby obtaining activated carbon.

2. The activated carbon according to claim 1, characterized in that The agricultural waste carbonization process comprises: The crushed agricultural waste was placed in a tubular furnace for carbonization. The carbonization temperature was 350~480 ℃, the carbonization time was 60~180 min, the heating rate was 5~15 ℃ / min, and the inert atmosphere flow rate was 200~400 mL / min.

3. The activated carbon according to claim 1, characterized in that The lithium removal process of the waste ternary lithium battery positive electrode material comprises: The positive electrode metal components are impregnated with acid, glucose is added to promote the leaching of metal ions, and then the metal ions in the leachate are precipitated by oxalic acid, the metal Li in the positive electrode material is separated, and the oxalate precipitate is dissolved by nitric acid; wherein, the impregnation temperature is 75~90 ℃, the impregnation time is 6~10 h, the acid concentration is 0.3~2 mol / L, the glucose addition amount is 0.1~0.5g / g, and the oxalic acid addition amount is 30~45 g / L.

4. The activated carbon according to claim 3, characterized in that During the lithium removal process of the waste ternary lithium battery positive electrode material, metal ion nitrates can also be added so that the concentration ratio of each metal ion in the final mixed metal ion solution satisfies the following: (800-1500) for Mn, Ni, Co, and Cu: (200-1000) : (200-1000) : (50-500) (in mg / L).

5. The activated carbon according to claim 1, characterized in that The process for preparing agricultural waste-based carbon loaded with metal components comprises: The mass ratio of agricultural waste-based carbon to Mn, Ni, Co, and Cu metal ions in the mixed metal ion solution is 20:1~20:4, and the immersion time is 2~8h.

6. The activated carbon according to claim 1, characterized in that During the activation process, the mass ratio of the agricultural waste-based carbon loaded with metal components to the alkaline activator is 1:1 to 1:

3.

7. The activated carbon according to claim 1 or 6, characterized in that During the activation process, the alkaline activator is KOH, NaOH or KHCO3.

8. The activated carbon according to claim 1, characterized in that During the activation process, the agricultural waste-based carbon loaded with metal components is ball-milled with an alkaline activator and then placed in a tube furnace for activation. After activation, it is cooled to room temperature. The activation temperature is 650-800°C, the activation time is 60-120 min, the heating rate is 5-15°C / min, and the inert atmosphere flow rate is 200-400 mL / min.

9. The activated carbon according to claim 1, characterized in that: After the activation process is completed, post-treatment is required, which includes pickling, water washing and drying.

10. A method for removing volatile organic matter and mercury from flue gas by adsorption, using an adsorbent to synergistically adsorb and remove volatile organic matter and mercury from flue gas; characterized in that: The adsorbent is the activated carbon described in claims 1-9.

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