Adsorbent for reducing emission of organic pollutants in waste copper recovery process and preparation method thereof

Abstract

The invention discloses an adsorbent for reducing emission of organic pollutants in a waste copper recovery process and a preparation method of the adsorbent, and belongs to the technical field of gas purification. The method comprises the following steps: according to a stoichiometric ratio, taking electroplating sludge and straw powder, adding water, mixing, uniformly stirring, drying to obtain a pyrolysis raw material, carrying out segmented pyrolysis carbonization modification on the obtained pyrolysis raw material, after the reaction is completed, removing unreacted materials, and drying to obtain the adsorbent. The electroplating sludge is added into the biomass charcoal, the biomass charcoal provides an adsorption carrier, the electroplating sludge provides an active component (NiO), the prepared adsorbent has physical adsorption, chemical adsorption and catalytic degradation at the same time, the adsorption effect of the adsorbent is remarkably improved, the adsorbent can be effectively used for adsorption of multiple VOCs in waste copper enameled wire pyrolysis flue gas, the adsorption efficiency is high, and the adsorption effect is good. And the device can be recycled.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification, and more specifically, relates to an adsorbent for reducing organic pollutants in the waste copper recycling process and a preparation method thereof. Background Art

[0002] With the rapid development of the global electronics industry, the generation of electronic waste has been increasing year by year, and its resource recovery and utilization has become a research hotspot in the environmental protection field. As an important part of electronic waste, waste copper enameled wire is often recycled by pyrolysis technology due to its high-purity copper content. This technology can achieve efficient metal recovery while reducing energy consumption and secondary pollution.

[0003] However, the organic coating on the surface of waste copper enameled wire will release a large amount of volatile organic compounds (VOCs) during the pyrolysis process, and at the same time produce highly toxic pollutants such as dioxins. Research data shows that the emission concentrations of VOCs and dioxins in the pyrolysis flue gas often exceed 200mg / m 3 3, far exceeding the national emission standard of 30mg / m 3 3. These pollutants not only pose a serious threat to human health, such as causing respiratory diseases and nervous system damage, but also exacerbate air pollution, leading to environmental problems such as photochemical smog and acid rain, seriously restricting the green and sustainable development of the electronic waste recycling industry. Therefore, efficiently removing VOCs during the pyrolysis of waste copper enameled wire has become a key technical bottleneck for achieving clean production.

[0004] At present, the adsorption technology, with its characteristics of simple operation and high treatment efficiency, has been widely used in the treatment of low-concentration and multi-component industrial waste gas. Biomass charcoal is regarded as a promising adsorbent due to its wide range of raw material sources (such as agricultural and forestry waste, waste wood materials, etc.) and low preparation cost. However, in practical applications, biomass charcoal has obvious defects: firstly, its specific surface area is relatively low, making it difficult to provide sufficient adsorption sites; secondly, the pore structure is unevenly distributed, resulting in significant differences in the adsorption efficiency of VOCs molecules with different molecular sizes and polarities, and unable to meet the high-efficiency adsorption requirements of diverse VOCs in complex industrial waste gas.

[0005] After retrieval, patents related to the modification of biochar to improve its adsorption effect have been publicly disclosed. For example, Chinese Patent Publication No.: CN115845798 A, Publication Date: March 28, 2023, Invention Title: A Modified Sludge Activated Carbon and Its Preparation Method and Application. The activated carbon disclosed in this patent includes the following raw material components: sludge particles, carbon enhancer, and binder; after mixing the raw materials, the carbonized material is obtained through carbonization treatment, and the carbonization treatment is carried out in an inert gas environment, with a carbonization temperature of 600°C to 800°C, a carbonization heating rate of 3 to 10°C / min, and a carbonization time of 0.5 to 3 hours; then the carbonized material is mixed with graphene oxide in a mass ratio of 1:(0.01 to 0.1), centrifuged for solid-liquid separation, and the solid product is dried to obtain the modified sludge activated carbon. The applicant prepared this modified sludge activated carbon according to the patent method in the laboratory and used it to adsorb VOCs in the pyrolysis flue gas of waste copper enameled wire. After testing, it was found that the emission reduction rate of VOCs in the pyrolysis flue gas of waste copper enameled wire by this modified sludge activated carbon was only 64.54%, and the pores of the sludge activated carbon were blocked after 6 hours of use and could not be used continuously, making it difficult to meet the application requirements of the industrial site. Therefore, there is an urgent need to develop a high-performance adsorption material for the characteristics of the pyrolysis flue gas of waste copper enameled wire to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the problem of poor adsorption effect in the adsorption of VOCs in the pyrolysis flue gas of waste copper enameled wire by using biochar in the prior art, and provides an adsorbent for reducing organic pollutants in the waste copper recycling process and its preparation method. By adding electroplating sludge to biochar, the biochar provides an adsorption carrier, and the electroplating sludge provides an active component (NiO). The prepared adsorbent has both physical adsorption, chemical adsorption, and catalytic degradation, significantly improving the adsorption effect of the adsorbent, being able to effectively adsorb various VOCs in the pyrolysis flue gas of waste copper enameled wire, having a high adsorption efficiency, and being recyclable.

[0007] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0008] First, a preparation method of an adsorbent for reducing organic pollutants in the waste copper recycling process provided by the present invention is to take electroplating sludge and straw powder according to the stoichiometric ratio, add water and mix them evenly, dry the mixture to obtain pyrolysis raw materials, perform segmented pyrolysis carbonization modification on the obtained pyrolysis raw materials, remove the unreacted materials after the reaction is completed, and dry to obtain the adsorbent.

[0009] The present invention uses straw as a raw material, modifies it by adding electroplating sludge, and mixes the straw with the electroplating sludge for staged pyrolysis to prepare an adsorbent. On the one hand, since the VOCs in the pyrolysis flue gas of waste copper enameled wire are mainly alkanes, ether compounds and ester compounds, and the molecular sizes of these compounds are different. The molecular sizes of alkanes vary, and ether and ester compounds also have their specific molecular sizes. After modifying the straw with electroplating sludge, NiO in the electroplating sludge interacts with biochar at high temperature. As a catalyst, NiO can promote the formation of more micropores and mesopores in biochar, increase the specific surface area, and help to adsorb VOCs with different molecular sizes in the pyrolysis flue gas of waste copper enameled wire, and the adsorption effect is good.

[0010] On the other hand, NiO in the electroplating sludge can combine with the surface functional groups of biochar to form new active sites and enhance the chemical adsorption of VOCs. By adopting the technical scheme of the present invention, the biochar provides an adsorption carrier, and the electroplating sludge provides an active component (NiO). The adsorbent prepared by combining the two has both physical adsorption, chemical adsorption and catalytic degradation, so that the prepared adsorbent can be effectively used for the adsorption of various VOCs in the pyrolysis flue gas of waste copper enameled wire, with high adsorption efficiency and recyclability.

[0011] As a further improvement of the present invention, the method of the present invention specifically includes the following steps:

[0012] Step S1, raw material preparation;

[0013] (1) Treatment of electroplating sludge: Place the electroplating sludge in an oven for drying, then crush the dried electroplating sludge, and screen the electroplating sludge with a metal sieve after crushing to obtain electroplating sludge with a particle size less than 250 μm;

[0014] (2) Pretreatment of straw: Put the straw into a crusher for crushing, then screen it to obtain straw powder with a particle size less than 100 μm, and then place the straw powder in an oven for drying.

[0015] Step S2, preparation of pyrolysis raw materials;

[0016] Mix the straw powder and electroplating sludge treated in step S1 according to a suitable mass ratio, then add deionized water, stir the mixture in a high-speed mixer to obtain a uniformly stirred slurry, and finally place the slurry in an oven for drying to obtain pyrolysis raw materials.

[0017] Step S3, co-pyrolysis modification;

[0018] Take the pyrolysis raw materials obtained in step S2 and carry out staged pyrolysis under the protection of an inert gas:

[0019] The first-stage pyrolysis: Heat the furnace with the first heating rate to 200-400 °C and pyrolyze for 30-60 min;

[0020] The second-stage pyrolysis: Heat the furnace with the second heating rate to 500-800 °C and pyrolyze for 60-120 min;

[0021] Among them, the first heating rate is higher than the second heating rate. After the second-stage pyrolysis is completed, cool it to room temperature to obtain the modified biochar.

[0022] It should be noted that when conventional biochar is treated by pyrolysis modification, it is usually a single-stage pyrolysis. During the research process, the applicant found that when the selected electroplating sludge is pyrolyzed with biochar, it needs to be pyrolyzed in stages. If direct single-stage high-temperature pyrolysis is carried out, the volatile components of biochar and electroplating sludge will be rapidly released at high temperature in a single stage, resulting in the pores being blocked by tar or incompletely decomposed organic matter, forming a closed pore structure, which not only fails to improve the pore structure of the adsorbent, but also significantly reduces the specific surface area of the prepared adsorbent, resulting in poor adsorption effect on VOCs. At the same time, at high temperature in a single stage, NiO in the electroplating sludge does not undergo gradient activation, and the particles are prone to agglomeration and cannot be effectively dispersed on the surface of biochar, making it difficult to efficiently adsorb various VOCs in the pyrolysis flue gas of waste copper enameled wire. In view of the above problems, through a large number of studies, the applicant found that after mixing the electroplating sludge and straw powder raw materials evenly, heat them to 200-400 °C at a first heating rate of 6-10 °C / min for the first-stage low-temperature pyrolysis reaction to promote biomass carbonization and volatile release. This is to avoid rapid carbonization of biomass and pore collapse and tar blockage caused by direct high-temperature pyrolysis, ensure the formation of a stable skeleton structure, effectively promote the decomposition of organic matter in the electroplating sludge, and reduce the blockage of pores by impurities in the subsequent high-temperature stage.

[0023] Then, heat it to 500-800 °C at a second heating rate of 3-5 °C / min for the second-stage high-temperature pyrolysis reaction. Use the pyrolysis reaction in this stage to activate the interaction between NiO and the carbon matrix, avoid uneven dispersion or insufficient catalytic activity caused by insufficient activation of NiO at low temperature, form a heterojunction interface between NiO and the carbon matrix, enhance the electron transfer ability, and promote the chemical adsorption and catalytic oxidation of VOCs.

[0024] In addition, it should be noted that the heating rate in the second-stage pyrolysis is lower than that in the first-stage pyrolysis. Such a setting is because the graphitization process of biochar and the metal activation reaction in the temperature range of 500-800 °C are sensitive to the heating rate. Too fast heating will cause local overheating, excessive contraction of the carbon skeleton, pore collapse, and a decrease in specific surface area. Slow heating allows uniform heat transfer, promotes the orderly reorganization of the carbon skeleton, enables the adsorbent to retain a high specific surface area, and can extend the migration time of metal Ni, avoid agglomeration, and ensure uniform dispersion.

[0025] Step S4: Acid treatment;

[0026] The modified biomass carbon obtained in step S3 is soaked in hydrochloric acid solution to remove unreacted impurities, then washed with deionized water until neutral, and then the washed modified biomass carbon is placed in an oven to dry, obtaining an adsorbent.

[0027] As a further improvement of the present invention, the straw powder and electroplating sludge are mixed in a mass ratio of (5 - 8):1, and deionized water is selected as the water, and the addition amount of deionized water is controlled to be 2 - 5 times the total mass of the solid. In addition to straw powder, other conventional biomass carbons can also be used as the biomass carbon.

[0028] The applicant has found through research that in the present invention, by adding electroplating sludge to biomass carbon for modification treatment, when the addition ratio of electroplating sludge is too low, NiO in the electroplating sludge cannot be effectively dispersed on the surface of the biomass carbon, resulting in insufficient catalytic activity and lack of chemical adsorption sites, and it cannot effectively promote the formation of micropores and mesopores during the pyrolysis process. When the addition ratio of electroplating sludge is too high, it will cause the aggregation of metal oxides in the electroplating sludge, reducing the exposed area of effective active sites and decreasing the chemical adsorption capacity of the adsorbent.

[0029] As a further improvement of the present invention, the electroplating sludge is dried before use, the drying temperature is 100 - 120 °C, and the drying time is 12 - 24 h.

[0030] As a further improvement of the present invention, the straw powder is placed in an oven at 100 - 120 °C to dry for 3 - 5 h.

[0031] As a further improvement of the present invention, when the straw powder and electroplating sludge are 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 to dry, and the drying time is 6 - 8 h.

[0032] As a further improvement of the present invention, the inert atmosphere can be N2, and the N2 flow rate is controlled at 200 mL / min during the two-stage pyrolysis reaction process.

[0033] As a further improvement of the present invention, the obtained modified biomass carbon is soaked in a hydrochloric acid solution with a concentration of 0.5 mol / L for 1 - 4 h to remove unreacted raw materials, then washed with deionized water until neutral, and then the washed modified biomass carbon is placed in an oven at 100 - 120 °C to dry for 12 - 24 h, obtaining an adsorbent.

[0034] Second, the present invention also provides an adsorbent for adsorbing organic pollutants in the process of reducing emissions and recycling waste copper. The adsorbent is prepared by the above method, and the sum of the proportions of its micropores and mesopores is greater than 80%, and the specific surface area is greater than 600 m 2 / g. It has excellent adsorption capacity for VOCs, and the adsorbent of the present invention has good effect, can be recycled, and has a long service life.

[0035] Third, the present invention also provides the application of the above adsorbent, which is used for the treatment of pyrolysis flue gas of waste copper enameled wire to adsorb organic pollutants in the pyrolysis flue gas. The adsorbent has excellent adsorption effect on various VOCs in the pyrolysis flue gas of waste copper enameled wire.

[0036] It should be noted that the main components of the electroplating sludge used in the present invention include: 35.39% of Fe2O3, 14.45 of NiO, 16.86% of ZnO, 10.51% of SiO2, 15.5% of Al2O3, and the rest are inevitable impurities.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] By using electroplating sludge to modify straw powder, the specific surface area of the prepared adsorbent material is significantly increased, the number of surface active sites is increased, it has a high adsorption efficiency for VOCs, is suitable for the adsorption treatment of VOCs in the pyrolysis flue gas of waste copper enameled wire, and the service life of the adsorbent is long. At the same time, by making full use of the electroplating sludge, a metallurgical industrial waste, and straw, the high-value conversion of electroplating sludge and biomass waste is realized, which conforms to the concept of green circular economy.

[0039] In addition, the 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

[0040] The present invention will be further described below in conjunction with specific embodiments.

[0041] Example 1

[0042] The preparation steps of the adsorbent in this example are specifically as follows:

[0043] Step 1. Raw material preparation

[0044] (1) Treatment of electroplating sludge:

[0045] First, dry the electroplating sludge in an oven at 105°C for 24 hours, then crush the dried electroplating sludge, and screen the electroplating sludge with a metal sieve after crushing to obtain electroplating sludge with a particle size less than 250 μm.

[0046] (2) Straw pretreatment: Put the straw into a crusher for crushing, then screen it. After screening, straw powder with a particle size less than 100 μm is obtained. Then, dry the straw powder in an oven at 105 °C for 10 h.

[0047] Step 2. Preparation of pyrolysis raw materials

[0048] Mix the straw powder and electroplating sludge in a mass ratio of 7:1, and add deionized water. The addition amount of water is controlled to be 3 times the total solid mass. Stir the mixture in a high-speed blender at a speed of 500 rpm / min for 2 h. Then, place the evenly stirred slurry in an oven at 105 °C and dry it for 8 h to obtain pyrolysis raw materials.

[0049] Step 3. Co-pyrolysis modification

[0050] Take 100 g of pyrolysis sample and put it into a tubular furnace. Under a N2 atmosphere, heat it up to 300 °C at a heating rate of 8 °C / min along with the furnace for the first-stage pyrolysis. The pyrolysis time is 45 min, and control the N2 flow rate to be 200 mL / min. After the first-stage pyrolysis is completed, under a N2 atmosphere, heat it up to 700 °C at a heating rate of 4 °C / min along with the furnace for the second-stage pyrolysis. The pyrolysis time is 90 min, and control the N2 flow rate to be 200 mL / min. After the second-stage pyrolysis is completed, wait for the sample to cool to room temperature to obtain modified biochar.

[0051] Step 4. Acid treatment

[0052] Soak the modified biochar in a hydrochloric acid solution with a concentration of 0.5 mol / L for 1.5 h to remove unreacted impurities. Then, wash it with deionized water until it is neutral. Then, place the washed modified biochar in an oven at 105 °C and dry it for 24 h to obtain the adsorbent.

[0053] Example 2

[0054] For the adsorbent of this example, the specific preparation steps are as follows:

[0055] Step 1. Raw material preparation

[0056] (1) Electroplating sludge treatment:

[0057] First, dry the electroplating sludge in an oven at 100 °C for 12 h. Then, crush the dried electroplating sludge. After crushing, use a metal sieve to screen the electroplating sludge. After screening, electroplating sludge with a particle size less than 250 μm is obtained.

[0058] (2) Straw pretreatment: Put the straw into a crusher for crushing, then screen it. After screening, straw powder with a particle size less than 100 μm is obtained. Then, dry the straw powder in an oven at 105 °C for 4 h.

[0059] Step 2: Preparation of pyrolysis raw materials

[0060] Mix the straw powder and electroplating sludge in a mass ratio of 5:1, 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 blender at a speed of 400 rpm / min for 1 h, and then the uniformly stirred slurry is placed in an oven at 100 °C and dried for 8 h to obtain the pyrolysis raw materials.

[0061] Step 3: Co-pyrolysis modification

[0062] Take 100 g of the pyrolysis sample and put it into a tubular furnace. Under a N2 atmosphere, it is heated to 400 °C at a heating rate of 6 °C / min for the first-stage pyrolysis. The pyrolysis time is 30 min, and the N2 flow rate is controlled at 200 mL / min. After the first-stage pyrolysis is completed, under a N2 atmosphere, it is heated to 800 °C at a heating rate of 5 °C / min for the second-stage pyrolysis. The pyrolysis time is 60 min, and the N2 flow rate is controlled at 200 mL / min. After the second-stage pyrolysis is completed, wait for the sample to cool to room temperature to obtain the modified biochar.

[0063] Step 4: Acid treatment

[0064] Soak the modified biochar in a hydrochloric acid solution with a concentration of 0.5 mol / L for 1.5 h to remove unreacted impurities, then wash it with deionized water until neutral, and then place the washed modified biochar in an oven at 105 °C and dry it for 24 h to obtain the adsorbent.

[0065] Example 3

[0066] For the adsorbent of this example, the preparation steps are specifically as follows:

[0067] Step 1: Raw material preparation

[0068] (1) Treatment of electroplating sludge:

[0069] First, dry the electroplating sludge in an oven at 110 °C for 15 h, then crush the dried electroplating sludge, and use a metal sieve to screen the electroplating sludge after crushing. The electroplating sludge with a particle size less than 250 μm is obtained after screening.

[0070] (2) Pretreatment of straw: Put the straw into a crusher for crushing, then screen it. The straw powder with a particle size less than 100 μm is obtained after screening, and then the straw powder is dried in an oven at 120 °C for 3 h.

[0071] Step 2: Preparation of pyrolysis raw materials

[0072] Mix the straw powder and electroplating sludge in a mass ratio of 6:1, 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 blender at a speed of 600 rpm / min for 2 h, and then the uniformly stirred slurry is placed in an oven at 115 °C and dried for 8 h to obtain the pyrolysis raw material.

[0073] Step 3: Co-pyrolysis modification

[0074] Put 100 g of the pyrolysis sample into a tubular furnace, and heat it up to 200 °C at a heating rate of 7 °C / min in an N2 atmosphere for the first-stage pyrolysis. The pyrolysis time is 60 min, and the N2 flow rate is controlled at 200 mL / min. After the first-stage pyrolysis is completed, heat it up to 600 °C at a heating rate of 4 °C / min in an N2 atmosphere for the second-stage pyrolysis. The pyrolysis time is 100 min, and the N2 flow rate is controlled at 200 mL / min. After the second-stage pyrolysis is completed, wait for the sample to cool to room temperature to obtain the modified biochar.

[0075] Step 4: Acid treatment

[0076] Soak the modified biochar in a hydrochloric acid solution with a concentration of 0.5 mol / L for 4 h to remove unreacted impurities, then wash it with deionized water until neutral, and then place the washed modified biochar in an oven at 105 °C and dry it for 24 h to obtain the adsorbent.

[0077] Example 4

[0078] The preparation steps of the adsorbent in this example are as follows:

[0079] Step 1: Raw material preparation

[0080] (1) Electroplating sludge treatment:

[0081] First, dry the electroplating sludge in an oven at 120 °C for 24 h, then crush the dried electroplating sludge, and use a metal sieve to screen the electroplating sludge after crushing. The electroplating sludge with a particle size less than 250 μm is obtained after screening.

[0082] (2) Straw pretreatment: Put the straw into a crusher for crushing, and then screen it. The straw powder with a particle size less than 100 μm is obtained after screening, and then the straw powder is dried in an oven at 100 °C for 5 h.

[0083] Step 2: Preparation of pyrolysis raw material

[0084] Mix the straw powder and electroplating sludge in a mass ratio of 8:1, and add deionized water. The amount of water added is controlled to be 5 times the total solid mass. The mixture is stirred in a high-speed blender at a speed of 450 rpm / min for 3 h, and then the uniformly stirred slurry is placed in an oven at 120 °C and dried for 7 h to obtain the pyrolysis raw material.

[0085] Step 3: Co-pyrolysis modification

[0086] Take 100 g of the pyrolysis sample and put it into a tubular furnace. Under a N2 atmosphere, it is heated up to 300 °C with the furnace at a heating rate of 10 °C / min for the first-stage pyrolysis. The pyrolysis time is 50 min, and the N2 flow rate is controlled at 200 mL / min. After the first-stage pyrolysis is completed, under a N2 atmosphere, it is heated up to 500 °C with the furnace at a heating rate of 3 °C / min for the second-stage pyrolysis. The pyrolysis time is 120 min, and the N2 flow rate is controlled at 200 mL / min. After the second-stage pyrolysis is completed, wait for the sample to cool to room temperature to obtain the modified biochar.

[0087] Step 4: Acid treatment

[0088] Soak the modified biochar in a hydrochloric acid solution with a concentration of 0.5 mol / L for 1 h to remove unreacted impurities, then wash it with deionized water until neutral, and then place the washed modified biochar in an oven at 105 °C and dry it for 24 h to obtain the adsorbent.

[0089] Comparative Example 1

[0090] For the preparation method of the adsorbent in this comparative example, its preparation method is basically the same as that of Example 1. The difference between it and Example 1 is only that when performing co-pyrolysis modification in Step 3, two-stage pyrolysis is not carried out, and it is directly pyrolyzed at 300 °C for 135 min.

[0091] Comparative Example 2

[0092] For the preparation method of the adsorbent in this comparative example, its preparation method is basically the same as that of Example 1. The difference between it and Example 1 is only that when performing co-pyrolysis modification in Step 3, two-stage pyrolysis is not carried out, and it is directly pyrolyzed at 700 °C for 135 min.

[0093] Comparative Example 3

[0094] For the adsorbent in this comparative example, its preparation method is basically the same as that of Example 1. The difference between it and Example 1 is only that: the straw powder and electroplating sludge are mixed in a mass ratio of 9:1.

[0095] Comparative Example 4

[0096] For the adsorbent in this comparative example, its preparation method is basically the same as that of Example 1. The difference between it and Example 1 is only that: the straw powder and sintering machine head ash are mixed in a mass ratio of 5:2.

[0097] The specific surface area, pore structure and adsorption effect of the adsorbent samples obtained in the above-mentioned 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 200 mg / m 3 were continuously introduced from the inlet, and a 3010MINIFID portable total hydrocarbon analyzer was used to detect the concentration of VOCs at the outlet of the adsorption device, and the adsorption time of the adsorbent was recorded simultaneously. The results are shown in Table 1.

[0098] Table 1 Performance detection results of the adsorbents obtained in each example and each comparative example of the present invention

[0099]

[0100] Combined with Table 1, it can be seen that the adsorbent prepared by the technical solution of the present invention effectively improves 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 has a high emission reduction efficiency and a long service life.

[0101] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art 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 organic pollutants in the process of waste copper recycling with emission reduction, characterized in that, According to the stoichiometric ratio, take electroplating sludge and straw powder, add water and mix them evenly, then dry them to obtain pyrolysis raw materials. Carry out two-stage pyrolysis carbonization modification on the obtained pyrolysis raw materials. After the reaction is completed, remove the unreacted materials and dry them to obtain the adsorbent. Among them, the pyrolysis temperature in the first stage is lower than that in the second stage.

2. The preparation method of the adsorbent according to claim 1, characterized in that The two-stage pyrolysis process is specifically as follows: The first-stage pyrolysis: Under the protection of an inert atmosphere, heat up to 200-400 °C at the first heating rate and pyrolyze for 30-60 min; The second-stage pyrolysis: Under the protection of an inert atmosphere, heat up to 500-800 °C at the second heating rate and pyrolyze for 60-120 min; The first heating rate is greater than the second heating rate.

3. The preparation method of the adsorbent according to claim 2, characterized in that, The first heating rate is 6-10 °C / min, and the second heating rate is 3-5 °C / min.

4. The preparation method of the adsorbent according to claim 1 or 2, characterized in that, The straw powder and electroplating sludge are mixed in a mass ratio of (5-8):

1. Deionized water is selected as the water, and the addition amount of deionized water is controlled to be 2-5 times the total mass of the solids.

5. The preparation method of the adsorbent according to claim 4, characterized in that: The particle size of the electroplating sludge is less than 250 μm, and the electroplating sludge is dried before use.

6. The preparation method of the adsorbent according to claim 4, characterized in that: The particle size of the straw powder is below 100 μm, and the straw powder is dried before use.

7. The preparation method of the adsorbent according to claim 5, characterized in that: The drying temperature of the electroplating sludge is 100-120 °C, and the drying time is 12-24 h.

8. The preparation method of the adsorbent according to claim 4, characterized in that: After the electroplating sludge and straw powder are mixed, stir them. 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; Immerse the modified biomass carbon in an acidic solution for 1-4 h to remove the unreacted raw materials.

9. An adsorbent for removing organic pollutants in the process of waste copper recycling with emission reduction, characterized in that: Prepared by the method according to any one of claims 1 to 8, the sum of the proportions of micropores and mesopores is greater than 80%, and the specific surface area is greater than 600 m 2 / g.

10. Use of an adsorbent as described in claim 9, characterized in that: Use it for the adsorption of VOCs in the pyrolysis flue gas of waste copper enameled wire.

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