Coal-based powdered activated carbon for garbage incineration and preparation method thereof

Abstract

The present invention relates to a coal-based powdered activated carbon for garbage incineration and a preparation method thereof, and belongs to the technical field of activated carbon. The present invention first carbonizes anthracite in a nitrogen atmosphere, and then adopts a combination of physical activation and chemical activation, sequentially physically activates in a carbon dioxide atmosphere, chemically activates after being impregnated with a potassium hydroxide solution, and acid washes after each activation to remove ash, thereby obtaining an activated carbon with developed mesopores, based on which an ionic liquid obtained by the action of 1-vinyl imidazole and 3-chloropropyl triethoxysilane with =N- and Cl- is added, thereby condensing hydroxyl groups and ethoxy groups on the activated carbon, realizing surface modification, modifying alkenyl and imidazole groups, and finally adding vinyl pyridine for double bond polymerization to form a pyridine group polymer with a low degree of polymerization, thereby preparing coal-based powdered activated carbon for garbage incineration, which has a very excellent adsorption effect on dioxins, high adsorption efficiency, and strong pertinence.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon, and in particular relates to coal-based powdered activated carbon for garbage incineration and a preparation method thereof. Background Art

[0002] Waste incineration is a process in which waste is oxidized at high temperature to reduce its volume through appropriate thermal decomposition, combustion, melting and other reactions to become residues or molten solid substances. It has become one of the current mainstream waste treatment methods due to its convenience, simple operation and many other advantages. However, since a type of highly toxic secondary pollutants, mainly dioxins, will be produced during the process of waste incineration, the tail gas produced by incineration is often post-treated in actual treatment. For example, activated carbon injection combined with bag dust removal technology is used to remove and remove dioxins. However, the existing activated carbon still has certain disadvantages that limit its application in activated carbon injection technology. This is because the mainstream activated carbon on the market is still mainly microporous activated carbon. Although microporous activated carbon can indeed have a good adsorption effect on small molecular organic pollutants, it has little adsorption effect on large molecular substances such as dioxins. It not only lacks specificity, resulting in seriously low adsorption efficiency, but also may cause emissions to fail to meet standards and harm the environment. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a coal-based powdered activated carbon for waste incineration and a preparation method thereof. The present invention first carbonizes anthracite in a nitrogen atmosphere, and then adopts a combination of physical activation and chemical activation, and sequentially performs physical activation in a carbon dioxide atmosphere, chemical activation after immersion in a potassium hydroxide solution, and acid washing is performed after each activation to remove ash, thereby obtaining an activated carbon with developed mesopores, based on which an ionic liquid obtained by the action of 1-vinylimidazole and 3-chloropropyltriethoxysilane via =N- and Cl- is added to condense hydroxyl groups and ethoxy groups on the activated carbon to achieve surface modification, modify the alkenyl and imidazole groups, and finally add vinylpyridine for double bond polymerization to form a pyridine group polymer with a low degree of polymerization, thereby preparing coal-based powdered activated carbon for waste incineration, which has a very excellent adsorption effect on dioxins, high adsorption efficiency and strong targeting.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A method for preparing coal-based powdered activated carbon for waste incineration, the method comprising the following steps:

[0006] (1) 8-10 parts by weight of anthracite is crushed and sieved to obtain a crushed material;

[0007] (2) carbonizing the crushed material under a nitrogen atmosphere, and then activating it once under a carbon dioxide atmosphere, then adding 20-25 parts by weight of an acid solution, stirring at room temperature for 30-60 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 50-60° C. until constant weight, to obtain a once activated material;

[0008] (3) adding 20-25 parts by weight of potassium hydroxide solution to the primary activated material, stirring and mixing at 30-35° C. for 8-10 hours, filtering, removing the filtrate, and finally drying at 80-100° C. for 1-2 hours, and naturally cooling to room temperature to obtain a pretreated material;

[0009] (4) reactivating the pretreated material under a nitrogen atmosphere, then adding 20-25 parts by weight of an acid solution, stirring at room temperature for 30-60 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 50-60° C. until constant weight, to obtain a reactivated material;

[0010] (5) adding the secondary activated material, 7-8 parts by weight of ionic liquid and 0.5-0.8 parts by weight of deionized water to 150-170 parts by weight of dimethyl sulfoxide, stirring at 80-90° C. in the dark for 20-24 hours, filtering, removing the filtrate, washing with anhydrous ethanol, and finally vacuum drying at 50-60° C. until constant weight, to obtain vinyl imidazole modified activated carbon;

[0011] (6) Add 10-15 parts by weight of deionized water, the vinyl imidazole-modified activated carbon, 2-2.5 parts by weight of vinyl pyridine and 0.3-0.5 parts by weight of potassium persulfate to 140-150 parts by weight of anhydrous ethanol, then stir at 70-75° C. for 12-14 hours, filter, remove the filtrate, wash with anhydrous ethanol, and finally vacuum dry at 50-60° C. until constant weight, and the preparation is completed.

[0012] As a preferred technical solution of the present invention, the screening in step (1) refers to screening through a 150-mesh sieve.

[0013] As a preferred technical solution of the present invention, the nitrogen atmosphere in step (2) refers to the introduction of nitrogen gas at a flow rate of 8-10 mL / min per gram of the crushed material; the carbonization refers to heating the temperature to 550-600°C at a heating rate of 10-15°C / min, and then keeping the temperature for 1-2 hours.

[0014] As a preferred technical solution of the present invention, the carbon dioxide atmosphere in step (2) refers to the introduction of carbon dioxide gas at a flow rate of 8-10 mL / min per gram of the crushed material; the primary activation refers to heating the temperature to 800-900°C at a heating rate of 10-15°C / min, then keeping warm for 2-3 hours, and naturally cooling to room temperature.

[0015] As a preferred technical solution of the present invention, the acid solution in step (2) refers to a hydrochloric acid solution with a mass fraction of 4-6%.

[0016] As a preferred technical solution of the present invention, the concentration of the potassium hydroxide solution in step (3) is 13-15 mol / L.

[0017] As a preferred technical solution of the present invention, the nitrogen atmosphere in step (4) refers to a nitrogen gas flow rate of 8-10mL / min per gram of the pretreated material; the secondary activation refers to heating the temperature to 800-850°C at a heating rate of 10-15°C / min, then keeping warm for 60-90min, and naturally cooling to room temperature.

[0018] As a preferred technical solution of the present invention, the acid solution in step (4) refers to a hydrochloric acid solution with a mass fraction of 4-6%.

[0019] As a preferred technical solution of the present invention, the ionic liquid in step (5) is prepared by the following steps:

[0020] Step A: add 5-10 parts by weight of anhydrous ethanol and 5-6 parts by weight of 1-vinylimidazole to 20-25 parts by weight of acetonitrile, stir at room temperature for 5-10 minutes to mix, then heat to 70-75° C. in a nitrogen atmosphere in the dark and keep warm, then add 4-5 parts by weight of 3-chloropropyltriethoxysilane dropwise while stirring, continue stirring at a constant temperature for 18-20 hours after the addition is completed, cool naturally to room temperature, distill under reduced pressure, and seal and store in the dark to complete the preparation.

[0021] Furthermore, the nitrogen atmosphere in step A refers to nitrogen gas introduced at a flow rate of 30-35 mL / min per gram of 1-vinylimidazole.

[0022] Furthermore, the heating rate in step A is 3-5°C.

[0023] Furthermore, the dripping rate in step A is controlled at 1-2 drops / s.

[0024] Furthermore, the reduced pressure distillation in step A refers to distillation at 35° C. under a vacuum degree of -0.07 MPa until the volatiles are completely removed.

[0025] A coal-based powdered activated carbon for waste incineration prepared by the preparation method as described above.

[0026] Beneficial effects of the present invention:

[0027] (1) The present invention first carbonizes anthracite in a nitrogen atmosphere, and then adopts a combination of physical activation and chemical activation, in which physical activation is carried out in a carbon dioxide atmosphere, followed by chemical activation after immersion in a potassium hydroxide solution, and acid washing is performed after each activation to remove ash, thereby obtaining an activated carbon with developed mesopores. Based on this, an ionic liquid obtained by the action of 1-vinylimidazole and 3-chloropropyltriethoxysilane via =N- and Cl- is added to condense the hydroxyl and ethoxy groups on the activated carbon to achieve surface modification, modify the alkenyl and imidazole groups, and finally add vinylpyridine for double bond polymerization to form a pyridine group polymer with a low degree of polymerization, thereby preparing a coal-based powdered activated carbon for waste incineration, which has a very excellent adsorption effect on dioxins, high adsorption efficiency, and strong targeting.

[0028] (2) The present invention is creatively based on the physicochemical properties of dioxins. The pore structure of the activated carbon itself is first optimized and improved. A combination of physical activation and chemical activation is adopted. In addition, each activation is followed by an acid wash to remove ash, thereby obtaining an activated carbon with developed mesopores. After being impregnated with a potassium hydroxide solution and then chemically activated, the micropores can be further expanded and formed through the action of an alkali, thereby increasing the proportion of mesopores in the activated carbon and enhancing the adsorption effect on macromolecular substances such as dioxins. At the same time, since the surface of the activated carbon itself contains a certain amount of oxygen-containing groups, such as hydroxyl groups, the present invention also adds an ion obtained by the action of 1-vinyl imidazole and 3-chloropropyltriethoxysilane via =N- and Cl- to the obtained activated carbon with developed mesopores. Liquid is used for surface modification. Through the condensation of hydroxyl and ethoxy groups (similar to the reaction between silane coupling agent and inorganic matter), ionic liquid is immobilized and modified with alkenyl and imidazole groups. The imidazole molecule has a 6-electron conjugated large π bond. Its introduction can greatly improve the π electron force on the surface of activated carbon, thereby promoting the adsorption of dioxins by activated carbon. The presence of alkenyl groups provides the possibility for subsequent polymerization with vinylpyridine to form a pyridine group polymer with a low degree of polymerization, so that the pyridine group can produce excellent synergistic effects with the imidazole group without causing excessive steric hindrance due to excessive polymerization to affect the adsorption of activated carbon itself. Finally, the two can jointly form a stronger π-π structure with dioxins, further promoting the adsorption of dioxins, and the adsorption is highly targeted.

[0029] (3) The present invention creatively improves the pore structure and surface functional groups of activated carbon, so that the prepared activated carbon has excellent adsorption effect when actually used for dioxin adsorption and has very good market application prospects. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0031] The anthracite in all the embodiments and comparative examples of the present invention is Taixi anthracite, industrial analysis: fixed carbon FC ad 89.29wt%, ash content A ad 2.68wt%, volatile matter V ad 7.80wt%, water content M ad 1.11wt%, total sulfur S t,ad It is 0.08wt%.

[0032] Example 1

[0033] A method for preparing coal-based powdered activated carbon for waste incineration, the method comprising the following steps:

[0034] (1) 8 parts by weight of anthracite is crushed and sieved to obtain a crushed material;

[0035] (2) carbonizing the crushed material under a nitrogen atmosphere, and then activating it once under a carbon dioxide atmosphere, then adding 20 parts by weight of an acid solution, stirring at room temperature for 30 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 50° C. until constant weight, to obtain a once activated material;

[0036] (3) adding 20 parts by weight of potassium hydroxide solution to the primary activated material, stirring and mixing at 30° C. for 8 h, filtering, removing the filtrate, and finally drying at 80° C. for 1 h, and naturally cooling to room temperature to obtain a pretreated material;

[0037] (4) The pretreated material was secondary activated under a nitrogen atmosphere, and then 20 parts by weight of an acid solution was added, stirred at room temperature for 30 minutes, filtered, the filtrate was removed, and washed with deionized water until neutral, and finally vacuum dried at 50° C. until constant weight, to obtain a secondary activated material;

[0038] (5) adding the secondary activated material, 7 parts by weight of ionic liquid and 0.5 parts by weight of deionized water to 150 parts by weight of dimethyl sulfoxide, stirring for 20 hours at 80° C. in the dark, filtering, removing the filtrate, washing with anhydrous ethanol, and finally drying in vacuo at 50° C. until constant weight, to obtain vinyl imidazole modified activated carbon;

[0039] (6) Add 10 parts by weight of deionized water, the vinyl imidazole-modified activated carbon, 2 parts by weight of vinyl pyridine and 0.3 parts by weight of potassium persulfate to 140 parts by weight of anhydrous ethanol, then stir at 70° C. for 12 h, filter, remove the filtrate, wash with anhydrous ethanol, and finally vacuum dry at 50° C. until constant weight, and the preparation is completed.

[0040] The sieving in step (1) refers to sieving through a 150-mesh sieve.

[0041] The nitrogen atmosphere in step (2) refers to the introduction of nitrogen gas at a flow rate of 8 mL / min per gram of the pulverized material; the carbonization refers to heating the temperature to 550° C. at a heating rate of 10° C. / min and then keeping the temperature for 1 hour.

[0042] The carbon dioxide atmosphere in step (2) refers to the introduction of carbon dioxide gas at a flow rate of 8 mL / min per gram of the crushed material; the primary activation refers to heating the temperature to 800°C at a heating rate of 10°C / min, then keeping the temperature for 2 hours, and naturally cooling to room temperature.

[0043] The acid solution in step (2) refers to a hydrochloric acid solution with a mass fraction of 4%.

[0044] The concentration of the potassium hydroxide solution in step (3) is 13 mol / L.

[0045] The nitrogen atmosphere in step (4) refers to the introduction of nitrogen gas at a flow rate of 8 mL / min per gram of the pretreated material; the secondary activation refers to heating the temperature to 800°C at a heating rate of 10°C / min, then keeping the temperature for 60 minutes, and naturally cooling to room temperature.

[0046] The acid solution in step (4) refers to a hydrochloric acid solution with a mass fraction of 4%.

[0047] The ionic liquid in step (5) is prepared by the following steps:

[0048] Step A: Add 5 parts by weight of anhydrous ethanol and 5 parts by weight of 1-vinylimidazole to 20 parts by weight of acetonitrile, stir at room temperature for 5 minutes, then heat to 70°C in a nitrogen atmosphere in the dark and keep warm, then add 4 parts by weight of 3-chloropropyltriethoxysilane dropwise while stirring, continue stirring at a constant temperature for 18 hours after the addition is completed, cool naturally to room temperature, distill under reduced pressure, and seal and store in the dark to complete the preparation.

[0049] The nitrogen atmosphere in step A refers to nitrogen gas introduced at a flow rate of 30 mL / min per gram of 1-vinylimidazole.

[0050] The heating rate in step A is 3°C.

[0051] The rate of dripping in step A is controlled at 1 drop / s.

[0052] The reduced pressure distillation in step A refers to distillation at 35° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0053] A coal-based powdered activated carbon for waste incineration prepared by the preparation method as described above.

[0054] Example 2

[0055] A method for preparing coal-based powdered activated carbon for waste incineration, the method comprising the following steps:

[0056] (1) 10 parts by weight of anthracite is crushed and sieved to obtain a crushed material;

[0057] (2) carbonizing the crushed material under a nitrogen atmosphere, and then activating it once under a carbon dioxide atmosphere, then adding 25 parts by weight of an acid solution, stirring at room temperature for 60 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 60° C. until constant weight, to obtain a once activated material;

[0058] (3) adding 25 parts by weight of potassium hydroxide solution to the primary activated material, stirring and mixing at 35° C. for 10 h, filtering, removing the filtrate, and finally drying at 100° C. for 2 h, and naturally cooling to room temperature to obtain a pretreated material;

[0059] (4) The pretreated material was reactivated under a nitrogen atmosphere, and then 25 parts by weight of an acid solution was added, stirred at room temperature for 60 minutes, filtered, the filtrate was removed, and washed with deionized water until neutral, and finally vacuum dried at 60° C. until constant weight, to obtain a reactivated material;

[0060] (5) adding the secondary activated material, 8 parts by weight of ionic liquid and 0.8 parts by weight of deionized water to 170 parts by weight of dimethyl sulfoxide, stirring at 90° C. in the dark for 24 hours, filtering, removing the filtrate, washing with anhydrous ethanol, and finally vacuum drying at 60° C. until constant weight, to obtain vinyl imidazole modified activated carbon;

[0061] (6) Add 15 parts by weight of deionized water, the vinyl imidazole-modified activated carbon, 2.5 parts by weight of vinyl pyridine and 0.5 parts by weight of potassium persulfate to 150 parts by weight of anhydrous ethanol, then stir at 75° C. for 14 h, filter, remove the filtrate, wash with anhydrous ethanol, and finally vacuum dry at 60° C. until constant weight, and the preparation is completed.

[0062] The sieving in step (1) refers to sieving through a 150-mesh sieve.

[0063] The nitrogen atmosphere in step (2) refers to the introduction of nitrogen gas at a flow rate of 10 mL / min per gram of the pulverized material; the carbonization refers to heating the temperature to 600°C at a heating rate of 15°C / min and then keeping the temperature for 2 hours.

[0064] The carbon dioxide atmosphere in step (2) refers to the introduction of carbon dioxide gas at a flow rate of 10 mL / min per gram of the crushed material; the primary activation refers to heating the temperature to 900°C at a heating rate of 15°C / min, then keeping the temperature for 3 hours, and naturally cooling to room temperature.

[0065] The acid solution in step (2) refers to a hydrochloric acid solution with a mass fraction of 6%.

[0066] The concentration of the potassium hydroxide solution in step (3) is 15 mol / L.

[0067] The nitrogen atmosphere in step (4) refers to the introduction of nitrogen gas at a flow rate of 10 mL / min per gram of the pretreated material; the secondary activation refers to heating the temperature to 850°C at a heating rate of 15°C / min, then keeping the temperature for 90 minutes, and naturally cooling to room temperature.

[0068] The acid solution in step (4) refers to a hydrochloric acid solution with a mass fraction of 6%.

[0069] The ionic liquid in step (5) is prepared by the following steps:

[0070] Step A: add 10 parts by weight of anhydrous ethanol and 6 parts by weight of 1-vinylimidazole to 25 parts by weight of acetonitrile, stir and mix at room temperature for 10 minutes, then heat to 75°C in a nitrogen atmosphere in the dark and keep warm, then add 5 parts by weight of 3-chloropropyltriethoxysilane dropwise while stirring, continue stirring at a constant temperature for 20 hours after the addition is completed, cool naturally to room temperature, distill under reduced pressure, seal and store in the dark, and the preparation is completed.

[0071] The nitrogen atmosphere in step A refers to nitrogen gas introduced at a flow rate of 35 mL / min per gram of 1-vinylimidazole.

[0072] The heating rate in step A is 5°C.

[0073] The rate of dripping in step A is controlled at 2 drops / s.

[0074] The reduced pressure distillation in step A refers to distillation at 35° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0075] A coal-based powdered activated carbon for waste incineration prepared by the preparation method as described above.

[0076] Example 3

[0077] A method for preparing coal-based powdered activated carbon for waste incineration, the method comprising the following steps:

[0078] (1) 9 parts by weight of anthracite is crushed and sieved to obtain a crushed material;

[0079] (2) carbonizing the crushed material under a nitrogen atmosphere, and then once activating it under a carbon dioxide atmosphere, then adding 23 parts by weight of an acid solution, stirring at room temperature for 50 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 55° C. until constant weight, to obtain a once activated material;

[0080] (3) adding 23 parts by weight of potassium hydroxide solution to the primary activated material, stirring and mixing at 33° C. for 9 h, filtering, removing the filtrate, and finally drying at 90° C. for 1.5 h, and naturally cooling to room temperature to obtain a pretreated material;

[0081] (4) The pretreated material was reactivated under a nitrogen atmosphere, and then 23 parts by weight of an acid solution was added, stirred at room temperature for 50 minutes, filtered, the filtrate was removed, and washed with deionized water until neutral, and finally vacuum dried at 55° C. until constant weight, to obtain a reactivated material;

[0082] (5) adding the secondary activated material, 7.5 parts by weight of ionic liquid and 0.6 parts by weight of deionized water to 160 parts by weight of dimethyl sulfoxide, stirring at 85° C. in the dark for 22 hours, filtering, removing the filtrate, washing with anhydrous ethanol, and finally vacuum drying at 55° C. until constant weight, to obtain vinyl imidazole modified activated carbon;

[0083] (6) Add 13 parts by weight of deionized water, the vinyl imidazole-modified activated carbon, 2.3 parts by weight of vinyl pyridine and 0.4 parts by weight of potassium persulfate to 145 parts by weight of anhydrous ethanol, then stir at 73° C. for 13 h, filter, remove the filtrate, wash with anhydrous ethanol, and finally vacuum dry at 55° C. until constant weight, and the preparation is completed.

[0084] The sieving in step (1) refers to sieving through a 150-mesh sieve.

[0085] The nitrogen atmosphere in step (2) refers to the introduction of nitrogen gas at a flow rate of 9 mL / min per gram of the pulverized material; the carbonization refers to heating the temperature to 580°C at a heating rate of 13°C / min and then keeping the temperature for 1.5 hours.

[0086] The carbon dioxide atmosphere in step (2) refers to the introduction of carbon dioxide gas at a flow rate of 9 mL / min per gram of the crushed material; the primary activation refers to heating the temperature to 850°C at a heating rate of 13°C / min, then keeping the temperature for 2.5 hours, and naturally cooling to room temperature.

[0087] The acid solution in step (2) refers to a hydrochloric acid solution with a mass fraction of 5%.

[0088] The concentration of the potassium hydroxide solution in step (3) is 14 mol / L.

[0089] The nitrogen atmosphere in step (4) refers to the introduction of nitrogen gas at a flow rate of 9 mL / min per gram of the pretreated material; the secondary activation refers to heating the temperature to 830°C at a heating rate of 13°C / min, then keeping the temperature for 80 minutes, and naturally cooling to room temperature.

[0090] The acid solution in step (4) refers to a hydrochloric acid solution with a mass fraction of 5%.

[0091] The ionic liquid in step (5) is prepared by the following steps:

[0092] Step A: Add 8 parts by weight of anhydrous ethanol and 5.5 parts by weight of 1-vinylimidazole to 23 parts by weight of acetonitrile, stir and mix at room temperature for 8 minutes, then heat to 73°C in a nitrogen atmosphere in the dark and keep warm, then add 4.5 parts by weight of 3-chloropropyltriethoxysilane dropwise while stirring, continue stirring at a constant temperature for 19 hours after the addition is completed, cool naturally to room temperature, distill under reduced pressure, seal and store in the dark, and the preparation is completed.

[0093] The nitrogen atmosphere in step A refers to nitrogen gas introduced at a flow rate of 33 mL / min per gram of 1-vinylimidazole.

[0094] The heating rate in step A is 4°C.

[0095] The rate of the dripping in step A is controlled at 1.5 drops / s.

[0096] The reduced pressure distillation in step A refers to distillation at 35° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0097] A coal-based powdered activated carbon for waste incineration prepared by the preparation method as described above.

[0098] Comparative Example 1

[0099] On the basis of Example 1, the potassium hydroxide solution in step (3) was replaced by an equal weight of deionized water, and the rest remained unchanged.

[0100] Comparative Example 2

[0101] Based on Example 1, step (5) and step (6) are not performed, and the rest remain unchanged.

[0102] Comparative Example 3

[0103] Based on Example 1, step (6) is not performed and the rest remain unchanged.

[0104] Comparative Example 4

[0105] On the basis of Example 1, the 2 parts by weight of vinyl pyridine in step (6) was changed to 3.5 parts by weight of vinyl pyridine, and the rest remained unchanged.

[0106] Comparative Example 5

[0107] On the basis of Example 1, the potassium hydroxide solution in step (3) was replaced with an equal weight of deionized water, and steps (5) and (6) were not performed, while the rest remained unchanged.

[0108] Test Example 1

[0109] Dioxin adsorption effect test:

[0110] The coal-based powdered activated carbon for waste incineration prepared in Examples 1-3 and Comparative Examples 1-5 were respectively tested for dioxin adsorption effect. The test method was carried out according to the description in the reference (Guo Xiangxin, Wang Peiyue, Ma Yunfeng, Lin Xiaoqing, Li Xiaodong. Experimental study on the influence of activated carbon pore parameters on dioxin gas phase adsorption [J]. Environmental Sanitation Engineering, 2020, 28(04): 52-56.).

[0111] Table 1. Dioxin adsorption test results

[0112] Total mass concentration removal efficiency / % Example 1 98.9 Example 2 99.2 Example 3 98.7 Comparative Example 1 40.1 Comparative Example 2 75.9 Comparative Example 3 84.4 Comparative Example 4 94.6 Comparative Example 5 43.7

[0113] Comparison between Example 1 and Comparative Examples 1-5 shows that:

[0114] The difference between Comparative Example 1 and Example 1 is that no potassium hydroxide solution is used for secondary activation, ie, chemical activation.

[0115] The difference between Comparative Example 2 and Example 1 is that no surface modification is performed.

[0116] The difference between Comparative Example 3 and Example 1 is that no pyridine group polymer with a low degree of polymerization is formed.

[0117] The difference between Comparative Example 4 and Example 1 is that a pyridine group polymer with a higher degree of polymerization is formed.

[0118] The difference between Comparative Example 5 and Example 1 is that no potassium hydroxide solution is used for secondary activation, ie, chemical activation, and no surface modification is performed.

[0119] From the comparison between Example 1 and Comparative Examples 1-5 in Test Example 1, it can be seen that the coal-based powdered activated carbon for waste incineration prepared by the present invention has a very excellent adsorption effect on dioxins.

[0120] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing coal-based powdered activated carbon for waste incineration, characterized in that: The preparation method comprises the following steps: (1) 8-10 parts by weight of anthracite is crushed and sieved to obtain a crushed material; (2) carbonizing the crushed material under a nitrogen atmosphere, and then activating it once under a carbon dioxide atmosphere, then adding 20-25 parts by weight of an acid solution, stirring at room temperature for 30-60 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 50-60° C. until constant weight, to obtain a once activated material; (3) adding 20-25 parts by weight of potassium hydroxide solution to the primary activated material, stirring and mixing at 30-35° C. for 8-10 hours, filtering, removing the filtrate, and finally drying at 80-100° C. for 1-2 hours, and naturally cooling to room temperature to obtain a pretreated material; (4) reactivating the pretreated material under a nitrogen atmosphere, then adding 20-25 parts by weight of an acid solution, stirring at room temperature for 30-60 minutes, filtering, removing the filtrate, washing with deionized water until neutral, and finally vacuum drying at 50-60° C. until constant weight, to obtain a reactivated material; (5) adding the secondary activated material, 7-8 parts by weight of ionic liquid and 0.5-0.8 parts by weight of deionized water to 150-170 parts by weight of dimethyl sulfoxide, stirring at 80-90° C. in the dark for 20-24 hours, filtering, removing the filtrate, washing with anhydrous ethanol, and finally vacuum drying at 50-60° C. until constant weight, to obtain vinyl imidazole modified activated carbon; (6) adding 10-15 parts by weight of deionized water, the vinyl imidazole-modified activated carbon, 2-2.5 parts by weight of vinyl pyridine and 0.3-0.5 parts by weight of potassium persulfate to 140-150 parts by weight of anhydrous ethanol, stirring at 70-75° C. for 12-14 hours, filtering, removing the filtrate, washing with anhydrous ethanol, and finally vacuum drying at 50-60° C. until constant weight, thereby completing the preparation; The ionic liquid in step (5) is prepared by the following steps: Step A: add 5-10 parts by weight of anhydrous ethanol and 5-6 parts by weight of 1-vinylimidazole to 20-25 parts by weight of acetonitrile, stir at room temperature for 5-10 minutes to mix, then heat to 70-75° C. in a nitrogen atmosphere in the dark and keep warm, then add 4-5 parts by weight of 3-chloropropyltriethoxysilane dropwise while stirring, continue stirring at a constant temperature for 18-20 hours after the addition is completed, cool naturally to room temperature, distill under reduced pressure, and seal and store in the dark to complete the preparation.

2. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The nitrogen atmosphere in step (2) refers to the introduction of nitrogen gas at a flow rate of 8-10 mL / min per gram of the pulverized material; the carbonization refers to heating the material to 550-600°C at a heating rate of 10-15°C / min and then keeping the temperature for 1-2 hours.

3. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The carbon dioxide atmosphere in step (2) refers to the introduction of carbon dioxide gas at a flow rate of 8-10 mL / min per gram of the pulverized material; the primary activation refers to heating the temperature to 800-900°C at a heating rate of 10-15°C / min, then keeping the temperature for 2-3 hours, and naturally cooling to room temperature.

4. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The concentration of the potassium hydroxide solution in step (3) is 13-15 mol / L.

5. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The nitrogen atmosphere in step (4) refers to the nitrogen gas flowing at a flow rate of 8-10 mL / min per gram of the pretreated material; the secondary activation refers to heating the temperature to 800-850°C at a heating rate of 10-15°C / min, then keeping the temperature for 60-90 minutes, and naturally cooling to room temperature.

6. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The heating rate in step A is 3-5°C.

7. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The dripping rate in step A is controlled at 1-2 drops / s.

8. The method for preparing coal-based powdered activated carbon for waste incineration according to claim 1, characterized in that: The reduced pressure distillation in step A refers to distillation at 35° C. under a vacuum degree of -0.07 MPa until the volatiles are completely removed.

9. A coal-based powdered activated carbon for waste incineration prepared by the preparation method according to any one of claims 1 to 8.