Adsorbent for treating VOCs (Volatile Organic Compounds) in waste copper enameled wire pyrolysis flue gas and preparation method thereof

Abstract

The invention discloses an adsorbent for treating VOCs in waste copper enameled wire pyrolysis flue gas and a preparation method of the adsorbent, and belongs to the technical field of gas purification. The preparation method comprises the following steps: according to a stoichiometric ratio, taking sintering machine head ash and sawdust powder, adding water, mixing, uniformly stirring, drying to obtain a mixture A, carrying out high-temperature carbonization modification on the obtained mixture A to obtain modified biomass charcoal, finally removing unreacted materials in the modified biomass charcoal, and drying to obtain the adsorbent. The prepared adsorbent is large in specific surface area, uniform in pore structure distribution, capable of being effectively used for adsorbing various VOCs in waste copper enameled wire pyrolysis flue gas, high in adsorption efficiency, capable of being recycled and long in service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification, and more specifically, relates to an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire and a preparation method thereof. Background Art

[0002] With the continuous increase of electronic waste, waste copper enameled wire, as an important part of it, has received extensive attention for its resource recovery and utilization. Waste copper enameled wire is usually recycled for high-purity copper through pyrolysis technology. However, due to the presence of an organic coating on the surface of waste copper enameled wire, VOCs will be generated during pyrolysis, and the emission concentrations of VOCs and dioxins often exceed 200 mg / m 3 , far higher than the national emission standard of 30 mg / m 3 . These VOCs have high toxicity and environmental hazards and are one of the main sources of air pollution. How to efficiently remove VOCs during the pyrolysis of waste copper enameled wire is a key technical problem for realizing clean production and sustainable development.

[0003] At present, the adsorption technology is widely used in the treatment of VOCs, especially suitable for the treatment of industrial waste gas with low concentration and multiple components. Biomass charcoal has attracted much attention because of its wide raw material sources and low preparation cost, and is regarded as a potential adsorption material. However, in practical applications, biomass charcoal still has the following deficiencies: the specific surface area of biomass charcoal is relatively low, and the pore structure distribution is uneven, which limits its adsorption capacity, resulting in poor adsorption performance for diverse VOCs molecules in complex industrial waste gas.

[0004] After retrieval, in the technical solution of the Chinese patent "Preparation Method and Application of a Super-High-Performance Biomass-Based Banana Peel-Derived Activated Carbon VOCs Adsorbent" (CN201911293894.7), it is proposed that: the banana peel is chopped, washed, dried and then carbonized to obtain banana peel biochar, and the banana peel biochar and KOH are uniformly mixed according to a certain mass ratio and then activated at high temperature, and then washed, filtered and dried to obtain a biochar VOCs adsorbent. For the above-mentioned scheme, the applicant once prepared this kind of biomass charcoal adsorbent in the laboratory and tried to use it to adsorb the VOCs generated during the pyrolysis of waste copper enameled wire, and found that the adsorption capacity of this kind of adsorbent for VOCs in the flue gas is weak, and the service life is short. After continuous adsorption for 2-3 hours, the adsorption effect seriously declines and it cannot be used continuously, making it difficult to be applied in enterprises.

[0005] Therefore, there is an urgent need for a new type of adsorbent that can effectively adsorb the organic pollutants generated during the pyrolysis of waste copper enameled wire. Summary of the Invention

[0006] 1. Problems to be Solved

[0007] In view of the deficiencies in the prior art that when using biomass charcoal to adsorb organic pollutants generated during the pyrolysis of waste copper enameled wire, the adsorption effect is not good and the service life is relatively short, an adsorbent using sintering machine head ash to modify biomass charcoal is proposed. When this material is used to treat organic pollutants in the flue gas during the pyrolysis of waste copper enameled wire, it exhibits excellent adsorption performance and cyclic regeneration ability.

[0008] In addition, the present invention also provides a preparation method of the above-mentioned adsorbent, and the preparation process is simple and the cost is low.

[0009] 2. Technical solution

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] An adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire provided by the present invention, according to the stoichiometric ratio, take sintering machine head ash and sawdust powder, add water and mix them, dry the mixture evenly after stirring to obtain mixture A, perform high-temperature carbonization modification on the obtained mixture A to obtain modified biomass charcoal, and finally remove the unreacted materials in the modified biomass charcoal and dry it to obtain the adsorbent.

[0012] The VOCs in the pyrolysis flue gas of waste copper enameled wire are mainly alkanes, ether compounds and ester compounds. These compounds have different molecular sizes. The molecular sizes of alkanes vary, and ether and ester compounds also have their specific molecular sizes. Therefore, the adsorbent needs to have a suitable pore structure, and micropores and mesopores need to cooperate with each other. Micropores can adsorb smaller molecular VOCs, and mesopores are beneficial for larger molecular alkanes, ether compounds and ester compounds to diffuse into the interior of the adsorbent, thereby improving the adsorption efficiency. The present invention uses sawdust powder as the raw material and modifies it by adding sintering machine head ash. During the pyrolysis process, the metal oxides contained in it promote gas release and carbonization reaction, forming more micropores and mesopores, optimizing the pore structure of the adsorbent. As a result, the prepared adsorbent has a larger specific surface area and a uniform pore structure distribution, can be effectively used for the adsorption of various VOCs in the pyrolysis flue gas of waste copper enameled wire, has a high adsorption efficiency, and can be recycled.

[0013] Furthermore, the sawdust powder and the sintering machine head ash are mixed in a mass ratio of 10:1 - 10:4, and deionized water is selected as the water, and the addition amount of deionized water is controlled to be 1 - 3 times the total mass of the solid. In addition to sawdust powder, other conventional biomass charcoals can also be used as the biomass charcoal.

[0014] It should be noted that the applicant has found through research that in the present invention, by adding sintering machine head ash to biomass charcoal for modification treatment, on the one hand, metal oxides such as K2O and Fe2O3 contained in the sintering machine head ash act as catalytic active centers, enhancing the adsorption capacity of biomass charcoal for polar and non-polar VOCs molecules. If the addition ratio of the sintering machine head ash is too low, the amount of these metal oxides is insufficient, and the catalytic effect cannot be fully exerted, making it difficult to significantly improve the adsorption capacity of the adsorbent for VOCs and difficult to efficiently adsorb various VOCs in the pyrolysis flue gas of waste copper enameled wire.

[0015] On the other hand, during the pyrolysis process, the metal oxides in the sintering machine head ash can promote gas release and carbonization reactions, forming more micropores and mesopores, optimizing the pore structure of the adsorbent. The presence of micropores and mesopores can greatly increase the specific surface area of the adsorbent, so that the adsorbent can fully contact with the VOCs in the pyrolysis flue gas of waste copper enameled wire, thereby improving the adsorption efficiency for various VOCs. At the same time, it can also increase the adsorption capacity of the adsorbent. During the recycling process of the adsorbent, these pore structures can remain relatively stable and are not easily damaged, enabling the adsorbent to be reused multiple times and extending its service life.

[0016] In addition, when the addition ratio of the sintering machine head ash is too low, this promoting effect weakens, the number of generated micropores and mesopores decreases, the specific surface area of the adsorbent is relatively small, and the pore structure distribution is not ideal, which is not conducive to the adsorption of VOCs. Moreover, when the addition amount is too small, the amount of basic oxides such as CaO in the sintering machine head ash is insufficient, and the acidic groups on the surface of the biomass charcoal cannot be fully neutralized, resulting in a limited increase in the adsorption sites for basic VOCs molecules and affecting the adsorption effect on basic VOCs.

[0017] Furthermore, in addition to the components beneficial to modification, the sintering machine head ash also contains impurities such as Pb, Zn, and Cl. When the addition ratio is too high, too many impurities will be introduced. These impurities may block the pores of the adsorbent and occupy the adsorption sites, thereby reducing the specific surface area and adsorption performance of the adsorbent.

[0018] Furthermore, the sintering machine head ash is screened to control the particle size of the sintering machine head ash not exceeding 200 mesh, and dechlorination treatment is carried out before mixing the sintering machine head ash. Chloride ions can change the surface charge and polarity of biomass charcoal, making it more hydrophilic. Usually, the surface of biomass charcoal has a certain hydrophobicity, which is beneficial to the adsorption of hydrophobic substances such as volatile organic compounds (VOCs). However, the presence of chlorine will increase the hydrophilicity of the charcoal, thereby affecting its adsorption capacity for hydrophobic VOCs. Therefore, in the present invention, by carrying out dechlorination treatment on the added sintering machine head ash, the adsorption capacity of the prepared adsorbent is further improved, especially for the adsorption of VOCs in the pyrolysis flue gas of waste copper enameled wire, and the adsorption effect is better.

[0019] Specifically, the method for dechlorination treatment of sintering machine head ash is as follows:

[0020] First, introduce nitrogen into the tubular furnace containing sintering machine head ash, and control the nitrogen flow rate to 200 mL / min. Then, heat it up to 300 - 500 °C at a heating rate of 10 - 15 °C / min. After the temperature stabilizes, use a steam generator to introduce high-purity water vapor into the tubular furnace, control the steam flow rate to 3 - 8 mL / min, and maintain it for 1 - 2 h. Stop introducing high-purity water vapor. After the sample naturally cools to room temperature, dechlorinated sintering machine head ash is obtained.

[0021] It should be noted that in addition to being able to adsorb VOCs, the adsorbent of the present invention is more suitable for adsorbing VOCs in the pyrolysis flue gas of waste copper enameled wire. Since the VOCs in the pyrolysis flue gas of waste copper enameled wire are mainly alkanes, ether compounds and ester compounds, the biomass carbon adsorbent modified with sintering machine head ash in the present invention has the following advantages: Metal oxides such as K2O and Fe2O3 contained in the sintering machine head ash act as catalytic active centers, enhancing the adsorption capacity for polar and non-polar VOCs molecules. Since ester compounds have functional groups such as carbonyl that can interact with the surface of the adsorbent, while alkanes are relatively difficult to adsorb. Basic oxides such as CaO in the sintering machine head ash can neutralize the acidic groups on the surface of the biomass carbon, increasing the adsorption sites for basic VOCs molecules, and may also change the surface properties of the adsorbent, enhancing the adsorption capacity for compounds such as esters.

[0022] Furthermore, put the sawdust into a crusher for crushing, and then perform screening. After screening, sawdust powder with a particle size of less than 0.5 mm is obtained. The sawdust powder is dried before use.

[0023] Furthermore, the sawdust powder is placed in an oven at 100 - 120 °C and dried for 3 - 5 h.

[0024] Furthermore, when the material is put into a high-speed mixer for stirring, the stirring speed is 400 - 600 rpm / min, the stirring time is 1 - 3 h, and the uniformly stirred slurry is placed in an oven at 100 - 120 °C for drying, and the drying time is 6 - 8 h.

[0025] Furthermore, place the mixture A in a tubular furnace, and heat it up to 600 - 700 °C for high-temperature carbonization at a heating rate of 10 - 15 °C / min under the protection of N2 atmosphere. The carbonization time is 1.5 - 3 h, control the N2 flow rate to 500 mL / min. After carbonization is completed, wait for the sample to cool to room temperature to obtain modified biomass carbon.

[0026] Further, the obtained modified biochar is soaked in a NaOH solution with a concentration of 1 mol / L for 1 - 4 h to remove unreacted impurities, then washed with deionized water until neutral, and then the washed modified biochar is placed in an oven at 100 - 120 °C and dried for 12 - 24 h to obtain the adsorbent.

[0027] The adsorbent for VOCs prepared by the above method has excellent adsorption capacity for various VOCs in the pyrolysis flue gas of waste copper enameled wire, and the adsorbent of the present invention has good effect, can be recycled, and has a long service life.

[0028] It should be noted that the composition of the sintering machine head ash used in the present invention includes: Fe 25.18%, K 18.46%, Na 8.29%, Pb 1.42%, Zn 0.28%, Cu 0.15%, Ca 4.91%, Cl 25.18%, and the rest are inevitable impurities.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] By using the sintering machine head ash to modify the sawdust powder, the specific surface area of the prepared adsorbent material is significantly increased, the surface active sites are increased, and it has a high adsorption efficiency for VOCs, which is suitable for the treatment of VOCs in the pyrolysis flue gas of waste copper enameled wire, and the adsorbent has a long service life. At the same time, by making full use of the sintering machine head ash, a metallurgical industrial waste, and sawdust, the high-value conversion of the sintering machine head ash and biomass waste is realized, which conforms to the concept of green circular economy.

[0032] In addition, the manufacturing raw materials of the adsorbent of the present invention are widely sourced and inexpensive, and the preparation process is simple, which is easy to be popularized and applied on a large scale. Specific embodiments

[0033] The present invention will be further described below in conjunction with specific embodiments.

[0034] Example 1

[0035] The adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire in this example is prepared as follows:

[0036] Step 1. Raw material preparation

[0037] (1) Sintering machine head ash vapor treatment:

[0038] First, screen the sintering machine head ash to obtain sintering machine head ash with a particle size of 200 mesh. Then, place 500 g of the screened sintering machine head ash sample in a tube furnace, introduce N2 into the tube furnace at a flow rate of 200 mL / min, and raise the temperature to 400 °C at a heating rate of 10 °C / min. After the temperature stabilizes, introduce high-purity water vapor into the tube furnace using a steam generator, control the steam flow rate to be 5 mL / min, and maintain for 1 h. Then stop the introduction of water vapor. After the sample naturally cools to room temperature, dechlorinated sintering machine head ash is obtained. The tube furnace is equipped with an alkaline solution absorption device to purify the waste gas, and the alkaline solution is 0.5 mol / L NaOH solution;

[0039] (2) Sawdust pretreatment: Put the sawdust into a crusher for crushing, then screen it. After screening, sawdust powder with a particle size of 0.5 mm is obtained. Then dry the sawdust powder in an oven at 105 °C for 4 h.

[0040] Step Two: Preparation of Mixture A

[0041] Mix the sawdust powder and the dechlorinated sintering machine head ash in a mass ratio of 10:3, and add deionized water. The addition amount of water is controlled to be 1.5 times the total solid mass. The mixture is stirred in a high-speed mixer at a speed of 500 rpm / min for 1.5 h. Then place the evenly stirred slurry in an oven at 105 °C and dry it for 6 h to obtain Mixture A.

[0042] Step Three: Preparation of Modified Biomass Char

[0043] Take 500 g of the Mixture A sample and put it into a tube furnace. Under a N2 atmosphere, heat it up to 600 °C in the furnace at a heating rate of 10 °C / min for high-temperature carbonization. The carbonization time is 3 h, control the N2 flow rate to be 500 mL / min. After carbonization is completed, wait for the sample to cool to room temperature to obtain modified biomass char.

[0044] Step Four: Preparation of Adsorbent

[0045] Soak the modified biomass char in 1 mol / L NaOH solution for 1 h to remove unreacted impurities, then wash it with deionized water until it is neutral. Then place the washed modified biomass char in an oven at 105 °C and dry it for 12 h to obtain the adsorbent.

[0046] Example 2

[0047] The adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire in this example is prepared as follows:

[0048] Step One: Raw Material Preparation

[0049] (1) Sintering Machine Head Ash Vapor Treatment:

[0050] First, screen the sintering machine head ash to obtain sintering machine head ash with a particle size of 200 mesh. Then, place 500 g of the screened sintering machine head ash sample in a tubular furnace, introduce N2 into the tubular furnace at a flow rate of 200 mL / min, and raise the temperature to 300 °C at a heating rate of 15 °C / min. After the temperature stabilizes, introduce high-purity water vapor into the tubular furnace using a steam generator, control the steam flow rate to be 3 mL / min, and maintain for 2 h. Then stop introducing water vapor. After the sample naturally cools to room temperature, dechlorinated sintering machine head ash is obtained. The tubular furnace is equipped with an alkaline solution absorption device to purify the waste gas, and the alkaline solution is 0.5 mol / L NaOH solution;

[0051] (2) Sawdust pretreatment: Put the sawdust into a crusher for crushing, then screen it. After screening, sawdust powder with a particle size of 0.5 mm is obtained. Then dry the sawdust powder in an oven at 120 °C for 3 h.

[0052] Step 2: Preparation of mixture A

[0053] Mix the sawdust powder and the dechlorinated sintering machine head ash in a mass ratio of 10:1, and add deionized water. The addition amount of water is controlled to be 2 times the total solid mass. The mixture is stirred in a high-speed mixer at a speed of 400 rpm / min for 3 h. Then place the uniformly stirred slurry in an oven at 120 °C and dry for 6 h to obtain mixture A.

[0054] Step 3: Preparation of modified biochar

[0055] Take 500 g of mixture A sample and put it into a tubular furnace. Under a N2 atmosphere, heat it up to 700 °C at a heating rate of 10 °C / min with the furnace for high-temperature carbonization. The carbonization time is 1.5 h, control the N2 flow rate to be 500 mL / min. After carbonization is completed, wait for the sample to cool to room temperature to obtain modified biochar.

[0056] Step 4: Preparation of adsorbent

[0057] Soak the modified biochar in 1 mol / L NaOH solution for 3 h to remove unreacted impurities, then wash it with deionized water until neutral. Then place the washed modified biochar in an oven at 100 °C and dry for 15 h to obtain the adsorbent.

[0058] Example 3

[0059] The adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire in this example is prepared as follows:

[0060] Step 1: Raw material preparation

[0061] (1) Sintering machine head ash vapor treatment:

[0062] First, screen the sintering machine head ash to obtain sintering machine head ash with a particle size of 200 mesh. Then, place 500 g of the screened sintering machine head ash sample in a tubular furnace, introduce N2 into the tubular furnace at a flow rate of 200 mL / min, raise the temperature to 500 °C at a heating rate of 12 °C / min. After the temperature stabilizes, introduce high-purity water vapor into the tubular furnace using a steam generator, control the steam flow rate to be 8 mL / min, and maintain for 1.5 h. Then stop the introduction of water vapor. After the sample naturally cools to room temperature, dechlorinated sintering machine head ash is obtained. The tubular furnace is equipped with an alkaline solution absorption device to purify the waste gas, and the alkaline solution is 0.5 mol / L NaOH solution;

[0063] (2) Sawdust pretreatment: Put the sawdust into a crusher for crushing, then screen it. After screening, sawdust powder with a particle size of 0.5 mm is obtained. Then dry the sawdust powder in an oven at 100 °C for 5 h.

[0064] Step Two: Preparation of Mixture A

[0065] Mix the sawdust powder and dechlorinated sintering machine head ash in a mass ratio of 10:3, and add deionized water. The addition amount of water is controlled to be 1.5 times the total solid mass. The mixture is stirred in a high-speed mixer at a speed of 500 rpm / min for 1 - 3 h. Then place the uniformly stirred slurry in an oven at 110 °C and dry it for 7 h to obtain Mixture A.

[0066] Step Three: Preparation of Modified Biomass Char

[0067] Take 500 g of the Mixture A sample and put it into a tubular furnace. Under an N2 atmosphere, heat it up to 680 °C with the furnace at a heating rate of 13 °C / min for high-temperature carbonization. The carbonization time is 2 h, control the N2 flow rate to be 500 mL / min. After carbonization is completed, wait for the sample to cool to room temperature to obtain modified biomass char.

[0068] Step Four: Preparation of Adsorbent

[0069] Soak the modified biomass char in 1 mol / L NaOH solution for 4 h to remove unreacted impurities, then wash it with deionized water until neutral. Then place the washed modified biomass char in an oven at 115 °C and dry it for 12 h to obtain the adsorbent.

[0070] Example 4

[0071] The adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire in this example is prepared as follows:

[0072] Step One: Raw Material Preparation

[0073] (1) Sintering Machine Head Ash Vapor Treatment:

[0074] First, screen the sintering machine head ash to obtain sintering machine head ash with a particle size of 200 mesh. Then, place 500 g of the screened sintering machine head ash sample in a tubular furnace, introduce N2 into the tubular furnace at a flow rate of 200 mL / min, and raise the temperature to 300 - 500 °C at a heating rate of 10 - 15 °C / min. After the temperature stabilizes, introduce high-purity water vapor into the tubular furnace using a steam generator, control the steam flow rate to be 6 mL / min, and maintain for 1 h. Then stop the introduction of water vapor. After the sample naturally cools to room temperature, dechlorinated sintering machine head ash is obtained. The tubular furnace is equipped with an alkaline solution absorption device to purify the waste gas, and the alkaline solution is 0.5 mol / L NaOH solution;

[0075] (2) Sawdust pretreatment: Put the sawdust into a crusher for crushing, then screen it. After screening, sawdust powder with a particle size of 0.5 mm is obtained. Then dry the sawdust powder in an oven at 110 °C for 4 h.

[0076] Step 2: Preparation of mixture A

[0077] Mix the sawdust powder and the dechlorinated sintering machine head ash in a mass ratio of 10:4, and add deionized water. The addition amount of water is controlled to be 3 times the total solid mass. The mixture is stirred in a high-speed mixer at a speed of 600 rpm / min for 1 h. Then place the uniformly stirred slurry in an oven at 100 °C and dry for 8 h to obtain mixture A.

[0078] Step 3: Preparation of modified biochar

[0079] Take 500 g of the mixture A sample and put it into a tubular furnace. Under a N2 atmosphere, heat it up to 650 °C at a heating rate of 15 °C / min with the furnace for high-temperature carbonization. The carbonization time is 3 h, control the N2 flow rate to be 500 mL / min. After carbonization is completed, wait for the sample to cool to room temperature to obtain modified biochar.

[0080] Step 4: Preparation of adsorbent

[0081] Soak the modified biochar in a 1 mol / L NaOH solution for 2 h to remove unreacted impurities, then wash it with deionized water until neutral. Then place the washed modified biochar in an oven at 120 °C and dry for 24 h to obtain the adsorbent.

[0082] Comparative example 1

[0083] For the adsorbent of this comparative example, directly pretreat the sawdust powder using the method of Example 1, then directly carbonize it without adding sintering machine head ash for modification treatment, and directly prepare the adsorbent product.

[0084] Comparative example 2

[0085] The adsorbent of this comparative example was prepared in substantially the same manner as in Example 1, and the difference from Example 1 was only that the sawdust powder and the sintering machine head ash were mixed at a mass ratio of 20:1.

[0086] Comparative Example 3

[0087] The adsorbent of this comparative example was prepared in substantially the same manner as in Example 1, and the difference from Example 1 was only that the sawdust powder and the sintering machine head ash were mixed at a mass ratio of 2:1.

[0088] Comparative Example 4

[0089] The adsorbent of this comparative example was prepared in substantially the same manner as in Example 1, and the difference from Example 1 was only that the sintering machine head ash was not subjected to dechlorination treatment.

[0090] The specific surface area, pore structure and adsorption effect of the adsorbent samples obtained in the above examples and comparative examples were detected. First, a fully automatic specific surface area and porosity analyzer was used to detect the specific surface area and pore size distribution of the adsorbent, and the detection results are shown in Table 1. Then, 200 g of the adsorbent was placed in the adsorption device, and VOCs with a concentration of 276.14 mg / m 3 were continuously introduced from the inlet, and a 3010MINIFID portable total hydrocarbon analyzer was used to detect the VOCs concentration at the outlet of the adsorption device, and the adsorption time of the adsorbent was recorded simultaneously. The results are shown in Table 1.

[0091] Table 1 Performance detection results of the adsorbents obtained in each example and each comparative example of the present invention

[0092]

[0093] Combined with Table 1, it can be seen that the adsorbent prepared by the technical solution of the present invention effectively increases the specific surface area of the adsorbent, and has more mesopores and micropores, significantly improving the adsorption effect of the adsorbent. At the same time, the adsorbent of the present invention also has a longer service life.

[0094] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire, characterized in that: According to the stoichiometric ratio, take the sintering machine head ash and sawdust powder, add water and mix them. After stirring evenly, dry them to obtain mixture A. Carry out high-temperature carbonization modification on the obtained mixture A to obtain modified biochar. Finally, remove the unreacted materials in the modified biochar and dry it to obtain the adsorbent.

2. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to claim 1, characterized in that: The sawdust powder and the sintering machine head ash are mixed in a mass ratio of 10:(1-4). Deionized water is selected as the water, and the addition amount of deionized water is controlled to be 1-3 times the total mass of the solids.

3. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to claim 1, characterized in that: The particle size of the sintering machine head ash is less than 200 mesh, and the sintering machine head ash is subjected to dechlorination treatment before mixing.

4. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to claim 3, characterized in that: The dechlorination treatment method of the sintering machine head ash is as follows: First, introduce nitrogen into the container containing the sintering machine head ash, and then heat it up to 300-500 °C at a heating rate of 10-15 °C / min. After the temperature is stable, introduce water vapor, control the water vapor flow rate to be 3-8 mL / min, and maintain it for 1-2 h. Stop the introduction of water vapor. After the sample naturally cools to room temperature, obtain the dechlorinated sintering machine head ash.

5. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to any one of claims 1 to 4, characterized in that: The particle size of the sawdust powder is below 0.5 mm, and the sawdust powder is dried before use.

6. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to claim 5, characterized in that: The drying temperature of the sawdust powder is 100-120 °C, and the drying time is 3-5 h.

7. A method for preparing an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to any one of claims 1 to 4, characterized in that: When preparing mixture A, the stirring speed is 400-600 rpm / min, the stirring time is 1-3 h, the drying temperature is 100-120 °C, and the drying time is 6-8 h.

8. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to any one of claims 1 to 4, characterized in that: During high-temperature carbonization, use inert gas protection, heat it up to the carbonization temperature of 600-700 °C at a heating rate of 10-15 °C / min, and the carbonization time is 1.5-3 h.

9. The preparation method of an adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire according to any one of claims 1 to 4, characterized in that: Soak the modified biochar with an alkaline solution for 1-4 h; the drying temperature is 100-120 °C, and dry it for 12-24 h.

10. An adsorbent for treating VOCs in the pyrolysis flue gas of waste copper enameled wire, characterized in that: Prepared by the method described in any one of claims 1-9.

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