Preparation method of irregular honeycomb activated carbon

Abstract

The present invention relates to the field of activated carbon technology, and discloses a method for preparing irregular honeycomb activated carbon, which uses partially calcined diatomaceous earth and uncalcined diatomaceous earth as raw materials. By utilizing the property that cellulose expands when heated and even gelatinizes when in contact with water, pores can be formed and bonded to the diatomaceous earth. The sample is fired at a high temperature to obtain a porous ceramic, and irregular pores are left due to the expansion of the cellulose. Activated carbon is prepared using recycled electrolytic aluminum carbon slag and jute stalks as carbon sources. Coal tar is used as a high-temperature adhesive, carboxymethyl cellulose is used as a low-temperature adhesive, and soybean oil is used as a plasticizer. The electrolytic aluminum carbon slag and jute stalk powder soaked in phosphoric acid are mixed to prepare an activated carbon reactant. The porous ceramic is impregnated and adsorbed in a molten state, and then sent into a reaction tube for carbonization and activation, and finally an irregular structure honeycomb activated carbon can be obtained.

Description

[0001] This case is a divisional application of the parent case with the patent application number 2023107497565, application date 2023-06-25, and titled "A honeycomb-type activated carbon with an irregular structure and its preparation method". Technical Field

[0002] The invention relates to the technical field of activated carbon, and in particular to a method for preparing irregular honeycomb activated carbon. Background Art

[0003] Activated carbon is a microcrystalline material primarily composed of carbon, with numerous pores and a large specific surface area. Its unique structure not only allows it to possess the characteristics of carbon materials, such as electrical and thermal conductivity and high mechanical strength, but also possesses advantages such as strong adsorption capacity and easy regeneration. Activated carbon can be classified by shape into granular activated carbon, columnar activated carbon, honeycomb activated carbon, and carbon fiber. Honeycomb activated carbon has a high porosity, large geometric surface area, short diffusion path, and, in particular, low pressure loss, offering broad application prospects in areas such as adsorption and catalysis. Currently, honeycomb activated carbon is primarily prepared by coating and integral extrusion. Patent application number 200410092429.4, "A Method for Directly Preparing Honeycomb Activated Carbon from Coal," discloses a method for preparing honeycomb activated carbon by pulverizing, batching, kneading, extrusion molding, drying, carbonization, and activation of coal powder, emulsified coal tar, a water-soluble binder, a lubricant, and water to obtain the final honeycomb activated carbon.

[0004] Porous ceramics can be used as a matrix for preparing honeycomb activated carbon using the coating method. Porous ceramics are inorganic, non-metallic materials with numerous micropores and a three-dimensional skeleton structure. Ceramic materials are inherently resistant to high temperatures, acids and alkalis, possess high mechanical strength, and are not easily deformed. Porous ceramics prepared from diatomaceous earth are not only inexpensive but also have high porosity. For example, the paper "Preparation and Research of Diatomaceous Earth-Based Porous Ceramics" reports on a relatively ideal porous ceramic prepared using diatomaceous earth as the primary raw material, clay as a binder, and sawdust as a pore-forming agent. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in response to the shortcomings of the existing technology, the present invention provides an irregularly structured honeycomb activated carbon and a preparation method thereof, which gives the honeycomb activated carbon a specific irregular structure, improves the adsorption rate, and is different from the honeycomb carbon on the market.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for preparing honeycomb activated carbon with an irregular structure, the preparation method is as follows:

[0008] Step 1, calcining the raw diatomaceous earth component 1 at a high temperature and then cooling it to 20-30°C to obtain calcined diatomaceous earth, drying the raw diatomaceous earth component 2 and cellulose at 75-85°C for 24-36 hours, then ball-milling and sieving the raw diatomaceous earth component 2 and the calcined diatomaceous earth together, adding deionized water to the sieved diatomaceous earth mixture and ball-milling for 6-10 hours, then adding cellulose and stirring for 1-4 hours, injecting the slurry into a mold and dry-pressing the molded sample, drying the molded sample at 85-95°C, and then sending it into a reactor and heating and calcining it in an air atmosphere. After naturally cooling to 20-35°C, a porous ceramic with an irregular structure is obtained;

[0009] Step 2: Dry and crush the jute stalks, stir and mix them with a phosphoric acid solution, boil them for 3-8 hours, filter them, and dry the filter residue to obtain jute stalk powder. Then, sieve the electrolytic aluminum carbon slag, wash it with water, and then dry and crush it. Then, add the jute stalk powder, coal tar, carboxymethyl cellulose, soybean oil and deionized water to the powder in sequence and mix them evenly. The mixture is repeatedly kneaded by hand into a mud-like state, and sent to a mud kneading machine for repeated mud kneading to obtain an activated carbon reactant. The activated carbon reactant is placed on an electric furnace at 140-160° C. to melt, and then placed in an irregularly structured porous ceramic for immersion adsorption for 30-50 minutes. The ceramic is taken out and cooled to 20-30° C., and the activated carbon reactant on the surface is removed to obtain a porous ceramic loaded with an activated carbon reactant.

[0010] Step 3: Place the porous ceramic loaded with activated carbon reactants in a reaction tube, heat it to 750°C at a rate of 3-5°C / min under a nitrogen atmosphere, and carbonize it for 2-4 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 2-4 hours, take out the product and cool it, wash it with deionized water several times, and dry it to obtain an irregularly structured honeycomb activated carbon.

[0011] Preferably, in step 1, the mass ratio of calcined diatomaceous earth, raw diatomaceous earth component 2, cellulose and deionized water is 18-24:15-20:15-25:35-45.

[0012] Preferably, the high temperature calcination in step 1 is performed at a temperature of 1100-1300° C. and for a time of 1-3 hours.

[0013] Preferably, the heating rate of the calcination in step 1 is 1-3°C / min, and the temperature is kept at 200°C, 300°C, 400°C, and 500°C for 1-3h respectively. After 500°C, the heating rate is 4-6°C / min, and the temperature is kept at 1000°C for 20-40min.

[0014] Preferably, in step 2, the mass ratio of jute stalks to phosphoric acid is 1:3.5-4.2.

[0015] Preferably, in step 2, the mass ratio of electrolytic aluminum carbon slag, jute stalk powder, coal tar, carboxymethyl cellulose, soybean oil and deionized water is 30-35:20-28:30-37:8-13:2-5:36-47.

[0016] The beneficial effects of the present invention are that it uses cheap and readily available diatomaceous earth as raw material. Uncalcined raw diatomaceous earth has a higher water absorption rate and porosity, while calcined diatomaceous earth has a higher bulk density and flexural strength. Therefore, the performance can be optimized by mixing part of the calcined diatomaceous earth with the uncalcined diatomaceous earth. By utilizing the property of cellulose to expand when heated by water or even gelatinize, diatomaceous earth can be formed and bonded. After dry pressing, the sample is fired at a high temperature to obtain porous ceramics, leaving irregular pores due to the expansion of cellulose. In order to respond to environmental protection policies, activated carbon is prepared using recycled electrolytic aluminum carbon slag and jute stalks as carbon sources. The main component of electrolytic aluminum carbon slag is carbon, and jute stalks are also high-quality materials for preparing activated carbon. Not only does it have a high lignin content, it also has a hollow porous structure, which can be decomposed and ablated using phosphoric acid. Using coal tar as a high-temperature adhesive, carboxymethyl cellulose as a low-temperature adhesive, and soybean oil as a plasticizer, electrolytic aluminum carbon slag and jute stalk powder soaked in superphosphate are mixed to prepare an activated carbon reactant. The porous ceramic is impregnated with it in a molten state. After the adsorption is completed, it is cooled to room temperature and sent into a reaction tube for carbonization. It is activated by water vapor to finally obtain a honeycomb activated carbon with an irregular structure. DETAILED DESCRIPTION

[0017] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the implementation methods.

[0018] Example 1

[0019] Step 1: 10 g of raw diatomaceous earth component 1 was calcined at 1200 ° C for 2 h and then cooled to 25 ° C to obtain calcined diatomaceous earth, the raw diatomaceous earth component 2 and cellulose were dried at 80 ° C for 30 h, and then 3 g of raw diatomaceous earth component 2 and 3.5 g of calcined diatomaceous earth were ball-milled and sieved together. 6.5 g of deionized water was added to the sieved diatomaceous earth mixture and ball-milled for 8 h. 3 g of cellulose was added and stirred for 2 h. The slurry was injected into a mold and dry-pressed. The molded sample was dried at 90 ° C and then sent to a reactor for heating and calcining in an air atmosphere at a heating rate of 2 ° C / min, and kept at 200 ° C, 300 ° C, 400 ° C, and 500 ° C for 2 h, respectively. After 500 ° C, the heating rate was 5 ° C / min, and kept at 1000 ° C for 30 min. After naturally cooling to 25 ° C, a porous ceramic with an irregular structure was obtained;

[0020] Step 2: Dry and crush 6g of jute stalks and stir and mix them with an aqueous solution containing 24.6g of phosphoric acid. Boil for 5h and then filter. Dry the filter residue to obtain jute stalk powder. Then sieve 16.3g of electrolytic aluminum carbon slag and wash it with water, then dry and crush it. Then, add 13g of jute stalk powder, 17.4g of coal tar, 5.6g of carboxymethyl cellulose, 2.1g of soybean oil and 19.7g of deionized water to the powder in sequence and mix them evenly. The mixture is manually kneaded into a mud-like state and sent to a mud machine for repeated mud kneading to obtain an activated carbon reactant. The activated carbon reactant is placed on an electric furnace and heated to melt at 150°C. Then, it is placed in an irregularly structured porous ceramic for immersion adsorption for 40min. The ceramic is taken out and cooled to 25°C. The activated carbon reactant on the surface is removed to obtain a porous ceramic loaded with activated carbon reactant.

[0021] Step 3: Place the porous ceramic loaded with activated carbon reactants in a reaction tube, heat it to 750°C at a rate of 5°C / min under a nitrogen atmosphere, and carbonize it for 4 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 4 hours, the product is taken out and cooled, washed with deionized water several times, and dried to obtain an irregularly structured honeycomb activated carbon.

[0022] Example 2

[0023] Step 1, 11g of raw diatomaceous earth component 1 was calcined at 1200°C for 2.5h and then cooled to 25°C to obtain calcined diatomaceous earth, the raw diatomaceous earth component 2 and cellulose were dried at 80°C for 32h, and then 2.8g of raw diatomaceous earth component 2 and 3.8g of calcined diatomaceous earth were ball-milled and sieved together, 6.2g of deionized water was added to the sieved diatomaceous earth mixture and ball-milled for 8h, and then 3.7g of cellulose was added and stirred for 3h. The slurry was injected into a mold and dry-pressed. The molded sample was dried at 90°C and then sent to a reactor for heating and calcining in an air atmosphere at a heating rate of 2°C / min, and respectively at 200°C, 300°C, 400°C, and 500°C for 2h. After 500°C, the heating rate was 5°C / min, and it was kept at 1000°C for 30min. After naturally cooling to 30°C, a porous ceramic with an irregular structure was obtained;

[0024] Step 2: Dry and crush 6g of jute stalks, stir and mix them with an aqueous solution containing 23g of phosphoric acid, boil for 5h, filter, and dry the filter residue to obtain jute stalk powder, then sieve and wash 16.5g of electrolytic aluminum carbon slag, then dry and crush, and then add 12g of jute stalk powder, 17.5g of coal tar, 6g of carboxymethyl cellulose, 2g of soybean oil and 20.5g of deionized water to the powder in sequence and mix evenly. The mixture is manually kneaded into a mud-like state, and sent to a mud kneading machine for repeated mud kneading to obtain an activated carbon reactant, which is placed on an electric furnace and heated to 150°C for melting, and then placed in an irregularly structured porous ceramic for immersion adsorption for 40min. The ceramic is taken out and cooled to 25°C, and the activated carbon reactant on the surface is removed to obtain a porous ceramic loaded with activated carbon reactant;

[0025] Step 3: Place the porous ceramic loaded with activated carbon reactant in a reaction tube, heat it to 750°C at a rate of 3°C / min under a nitrogen atmosphere, and carbonize it for 2 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 2 hours, take out the product and cool it, wash it with deionized water several times, and dry it to obtain a honeycomb activated carbon with an irregular structure.

[0026] Example 3

[0027] Step 1, 8g of raw diatomaceous earth component 1 was calcined at 1100°C for 1h and then cooled to 20°C to obtain calcined diatomaceous earth, the raw diatomaceous earth component 2 and cellulose were dried at 75°C for 24h, and then 2.5g of raw diatomaceous earth component 2 and 3g of calcined diatomaceous earth were ball-milled and sieved together, 5.8g of deionized water was added to the sieved diatomaceous earth mixture and ball-milled for 6h, and then 2.5g of cellulose was added and stirred for 1h. The slurry was injected into a mold and dry-pressed. The molded sample was dried at 85°C and then sent to a reactor for heating and calcining in an air atmosphere at a heating rate of 1°C / min, and respectively kept at 200°C, 300°C, 400°C, and 500°C for 1h. After 500°C, the heating rate was 4°C / min, and kept at 1000°C for 20min. After naturally cooling to 20°C, a porous ceramic with an irregular structure was obtained;

[0028] Step 2: Dry and crush 6g of jute stalks and stir and mix them with an aqueous solution containing 25.2g of phosphoric acid. Boil for 8h and then filter. Dry the filter residue to obtain jute stalk powder. Then sieve and wash 17.5g of electrolytic aluminum carbon slag, then dry and crush it. Then, add 14g of jute stalk powder, 18.5g of coal tar, 6.5g of carboxymethyl cellulose, 2.5g of soybean oil and 23.5g of deionized water to the powder in sequence and mix evenly. Knead the mixture repeatedly by hand into a mud-like state, send it into a mud machine and repeatedly knead the mud to obtain an activated carbon reactant, heat it to melt at 160°C on an electric furnace, and then put it into an irregularly structured porous ceramic for immersion adsorption for 50min. Take out the ceramic and cool it to 30°C, remove the activated carbon reactant on the surface, and obtain a porous ceramic loaded with activated carbon reactant.

[0029] Step 3: Place the porous ceramic loaded with activated carbon reactants in a reaction tube, heat it to 750°C at a rate of 4°C / min under a nitrogen atmosphere, and carbonize it for 2.5 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 3 hours, the product is taken out and cooled, washed with deionized water several times, and dried to obtain an irregularly structured honeycomb activated carbon.

[0030] Example 4

[0031] Step 1, 13g of raw diatomaceous earth component 1 was calcined at 1300°C for 3h and then cooled to 25°C to obtain calcined diatomaceous earth, the raw diatomaceous earth component 2 and cellulose were dried at 85°C for 36h, and then 3.3g of raw diatomaceous earth component 2 and 4g of calcined diatomaceous earth were ball-milled and sieved together, 7.5g of deionized water was added to the sieved diatomaceous earth mixture and ball-milled for 10h, and then 4.2g of cellulose was added and stirred for 4h. The slurry was injected into a mold and dry-pressed. The molded sample was dried at 95°C and then sent to a reactor for heating and calcining in an air atmosphere at a heating rate of 3°C / min, and respectively at 200°C, 300°C, 400°C, and 500°C for 3h. After 500°C, the heating rate was 6°C / min, and it was kept at 1000°C for 40min. After naturally cooling to 35°C, a porous ceramic with an irregular structure was obtained;

[0032] Step 2: Dry and crush 6g of jute stalks and stir and mix them with an aqueous solution containing 21g of phosphoric acid. Boil for 3h and then filter. Dry the filter residue to obtain jute stalk powder. Then sieve 15g of electrolytic aluminum carbon slag and wash it with water, then dry and crush it. Then, add 10g of jute stalk powder, 15g of coal tar, 4g of carboxymethyl cellulose, 1g of soybean oil and 18g of deionized water to the powder in sequence and mix them evenly. Manually knead the mixture repeatedly into a mud-like state, send it into a mud machine and repeatedly knead the mud to obtain an activated carbon reactant, heat it to melt at 140°C on an electric furnace, and then put it into an irregularly structured porous ceramic for immersion adsorption for 30min. Take out the ceramic and cool it to 20°C, remove the activated carbon reactant on the surface, and obtain a porous ceramic loaded with activated carbon reactant;

[0033] Step 3: Place the porous ceramic loaded with activated carbon reactant in a reaction tube, heat it to 750°C at a rate of 5°C / min under a nitrogen atmosphere, and carbonize it for 2 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 4 hours, take out the product and cool it, wash it with deionized water several times, and dry it to obtain an irregular structure of honeycomb activated carbon.

[0034] Example 5

[0035] Step 1, 3g of raw diatomaceous earth component 1 was calcined at 1100°C for 3h and then cooled to 20°C to obtain calcined diatomaceous earth, the raw diatomaceous earth component 2 and cellulose were dried at 85°C for 24h, and then 3.3g of raw diatomaceous earth component 2 and 3g of calcined diatomaceous earth were ball-milled and sieved together, 7.5g of deionized water was added to the sieved diatomaceous earth mixture and ball-milled for 6h, and then 4.2g of cellulose was added and stirred for 1h. The slurry was injected into a mold and dry-pressed. The molded sample was dried at 95°C and then sent to a reactor for heating and calcining in an air atmosphere at a heating rate of 1°C / min, and respectively at 200°C, 300°C, 400°C, and 500°C for 3h, and after 500°C, the heating rate was 4°C / min, and kept at 1000°C for 40min. After naturally cooling to 20°C, a porous ceramic with an irregular structure was obtained;

[0036] Step 2: Dry and crush 6g of jute stalks, stir and mix them with an aqueous solution containing 25.2g of phosphoric acid, boil for 3h, filter, and dry the filter residue to obtain jute stalk powder, then sieve and wash 17.5g of electrolytic aluminum carbon slag, then dry and crush, and then add 10g of jute stalk powder, 18.5g of coal tar, 4g of carboxymethyl cellulose, 2.5g of soybean oil and 18g of deionized water to the powder in sequence and mix evenly. The mixture is manually kneaded into a mud-like state, and sent to a mud machine for repeated mud kneading to obtain an activated carbon reactant, which is placed on an electric furnace at 160°C for heating and melting, and then placed in an irregularly structured porous ceramic for immersion adsorption for 30min. The ceramic is taken out and cooled to 30°C, and the activated carbon reactant on the surface is removed to obtain a porous ceramic loaded with activated carbon reactant;

[0037] Step 3: Place the porous ceramic loaded with activated carbon reactant in a reaction tube, heat it to 750°C at a rate of 4°C / min under a nitrogen atmosphere, and carbonize it for 3 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 3 hours, take out the product and cool it, wash it with deionized water several times, and dry it to obtain a honeycomb activated carbon with an irregular structure.

[0038] The N2 adsorption-desorption isotherm of the product was measured using a specific surface area meter, and the average pore size and pore volume were obtained based on the data using the BET equation and the BJH calculation model.

[0039] The mechanical strength is tested according to the national standard GB / T2006-2008.

[0040]

[0041] According to the table, the specific surface area of ​​the honeycomb activated carbon prepared by the present invention is about 390-410 m2 / g, the pore volume is about 0.4-0.5 cm3 / g, and the mechanical strength is about 7.0-8.5 MPa.

Claims

1. A method for preparing irregular honeycomb activated carbon, characterized in that: The preparation method is as follows: Step 1, calcining the raw diatomaceous earth component 1 at a high temperature and then cooling it to 20-30°C to obtain calcined diatomaceous earth, drying the raw diatomaceous earth component 2 and cellulose at 75-85°C for 24-36 hours, then ball-milling and sieving the raw diatomaceous earth component 2 and the calcined diatomaceous earth together, adding deionized water to the sieved diatomaceous earth mixture and ball-milling for 6-10 hours, then adding cellulose and stirring for 1-4 hours, injecting the slurry into a mold and dry-pressing it, drying the molded sample at 85-95°C, then heating and calcining it in an air atmosphere, and cooling it to 20-35°C to obtain a porous ceramic with an irregular structure; the high-temperature calcination temperature in step 1 is 1100-1300°C; Step 2: Dry and crush the jute stalks, stir and mix them with a phosphoric acid solution, boil them for 3-8 hours, filter them, and dry the filter residue to obtain jute stalk powder. Then, sieve the electrolytic aluminum carbon slag, wash it with water, and then dry and crush it. Then, add the jute stalk powder, coal tar, carboxymethyl cellulose, soybean oil and deionized water to the powder in sequence, mix them, knead the mixture into a mud, send it into a mud machine and repeatedly knead it to obtain an activated carbon reactant, heat it on an electric furnace at 140-160° C. to melt it, and then put it into an irregularly structured porous ceramic for immersion adsorption for 30-50 minutes. Take out the ceramic and cool it to 20-30° C., remove the activated carbon reactant on the surface, and obtain a porous ceramic loaded with activated carbon reactant. The mass ratio of electrolytic aluminum carbon slag, jute stalk powder, coal tar, carboxymethyl cellulose, soybean oil and deionized water is 15-17.5:10-14:15-18.5:4-6.5:1-2.5:18-23.5; Step 3: Place the porous ceramic loaded with activated carbon reactants in a reaction tube, heat it to 750°C at a rate of 3-5°C / min under a nitrogen atmosphere, and carbonize it for 2-4 hours. After the carbonization is completed, water vapor is introduced into the reaction tube for activation. After 2-4 hours, take out the product and cool it, wash it with deionized water several times, and dry it to obtain an irregularly structured honeycomb activated carbon.

2. The method for preparing irregular honeycomb activated carbon according to claim 1, wherein: The high temperature calcination time in the step 1 is 1-3 hours.

3. The method for preparing irregular honeycomb activated carbon according to claim 1, wherein: The heating rate of the calcination in the step 1 is 1-3°C / min, and the temperature is kept at 200°C, 300°C, 400°C, and 500°C for 1-3 hours respectively. After 500°C, the heating rate is 4-6°C / min, and the temperature is kept at 1000°C for 20-40 minutes.

4. The method for preparing irregular honeycomb activated carbon according to claim 1, wherein: In the step 2, the mass ratio of jute stalks to phosphoric acid is 1:3.5-4.2.

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