Preparation process and application of nano-grade activated carbon

Abstract

The present invention relates to a preparation process and application of nano-scale activated carbon, and belongs to the technical field of activated carbon. A preparation process of nano-scale activated carbon comprises: mixing treated rice husk particles, mercaptopropionic acid and deionized water, adjusting the pH value, adding zinc chloride and stirring, drying and calcining, washing and drying to obtain prefabricated activated carbon; mixing prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water, ultrasonically treating, drying and calcining, washing and drying to obtain. In the present invention, mercaptopropionic acid enters the interior of rice husk particles, which helps to form an activated carbon skeleton structure, and then increases the coordination ability with zinc ions under acidic conditions, and when zinc chloride acts as an activator, it reduces the burning loss of raw materials, and helps to form activated carbon with a porous structure, promotes the subsequent adsorption of zirconium ions, and finally calcined so that zirconium oxide is dispersed on the surface of activated carbon to form zirconium-based activated carbon.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon and relates to a preparation process and application of nano-level activated carbon. Background Art

[0002] As an adsorption material widely used in various fields, activated carbon performs well in treating organic pigment wastewater. Specifically, activated carbon has a significant effect in removing organic pigments such as methylene blue, acid red 18 and Congo red. Methylene blue is a common dye widely used in textile, papermaking and biological dyeing, but its wastewater discharge will cause serious pollution to the environment. Acid red 18 and Congo red are also commonly used dyes, which will also pollute water bodies. Activated carbon can effectively adsorb these organic pigment molecules through its porous structure and high specific surface area, thereby achieving the purpose of purifying wastewater. Studies have shown that in the process of adsorbing methylene blue, acid red 18 and Congo red, activated carbon not only has high adsorption efficiency, but also has good regeneration performance, and can maintain a high adsorption capacity after multiple uses. Therefore, the application of activated carbon in the treatment of organic pigment wastewater has broad development prospects.

[0003] Zirconia nanorods have a very high specific surface area due to their small size and high surface atomic ratio, which means that they have a large number of adsorption sites. These sites can interact with organic pigment molecules through physical adsorption or chemical adsorption. Summary of the invention

[0004] The purpose of the present invention is to provide a nano-scale activated carbon and its preparation process and application. In the present invention, mercaptopropionic acid enters into the interior of rice husk particles, which helps to form an activated carbon skeleton structure. Then, under acidic conditions, the coordination ability with zinc ions is increased. When zinc chloride acts as an activator, the burning loss of raw materials is reduced, and it helps to form activated carbon with a porous structure, promotes the subsequent adsorption of zirconium ions, and finally, after calcination, zirconium oxide is dispersed on the surface of the activated carbon to form zirconium-based activated carbon.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A preparation process of nano-scale activated carbon, the preparation process comprising the following steps:

[0007] 1) washing the rice husk, sieving it, and drying it in an oven to obtain rice husk particles;

[0008] 2) After the rice husk particles, mercaptopropionic acid and deionized water are stirred and mixed, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried for a second time to obtain prefabricated activated carbon;

[0009] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then subjected to ultrasonic treatment, placed in an oven for drying, placed in a tubular furnace for calcination, washed and dried twice to obtain the product.

[0010] As a preferred technical solution of the present invention, in step 1), the sieving is grinding through a 120-mesh sieve; and the drying is drying at 60-80° C. for 5-8 hours.

[0011] As a preferred technical solution of the present invention, in step 2), the stirring and mixing is stirring at a speed of 500-600 r / min for 45-60 min; the drying is drying at a temperature of 105-110°C for 4-5 h; the washing is washing 3 times with deionized water; and the secondary drying is drying at a temperature of 105-110°C to constant weight.

[0012] As a preferred technical solution of the present invention, in step 2), the calcination is performed by heating to a temperature of 600-700° C. at a heating rate of 10° C. / min for 1.5-2.0 h.

[0013] As a preferred technical solution of the present invention, in step 2), the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 12-15:1.2-1.5:24-30:10-13; and the pH value is adjusted to 6.0-6.5.

[0014] As a preferred technical solution of the present invention, in step 3), the mixing is mixing at a rotation speed of 200-300r / min for 20-30min; the ultrasonic treatment is ultrasonic treatment at a frequency of 400-500W for 30-45min; the drying is drying at a temperature of 110-120°C for 3-4h; the washing is washing twice with deionized water; and the secondary drying is drying at a temperature of 70-80°C for 10-12h.

[0015] As a preferred technical solution of the present invention, in step 3), the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 3.0-5.0:1.0-1.6:15-20.

[0016] As a preferred technical solution of the present invention, in step 3), the calcination is performed by heating to a temperature of 900-980° C. at a heating rate of 10° C. / min for 2.0-3.0 h.

[0017] The invention discloses nanometer-scale activated carbon prepared by the above-mentioned preparation process, and application of the activated carbon in the field of organic matter adsorption.

[0018] Beneficial effects of the present invention:

[0019] The present invention allows mercaptopropionic acid to enter the interior of rice husk particles, which helps to form an activated carbon skeleton structure. Then, under acidic conditions, the coordination ability with zinc ions is increased. When zinc chloride acts as an activator, it reduces the burning loss of raw materials and helps to form activated carbon with a porous structure, thereby promoting the subsequent adsorption of zirconium ions. Finally, after calcination, zirconium oxide is dispersed on the surface of the activated carbon to form zirconium-based activated carbon. DETAILED DESCRIPTION

[0020] 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.

[0021] Example 1

[0022] A preparation process of nano-scale activated carbon comprises the following steps:

[0023] 1) washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; the sieving is grinding them through a 120-mesh sieve; and the drying is drying them at 60° C. for 5 hours;

[0024] 2) After stirring and mixing the rice husk particles, mercaptopropionic acid and deionized water, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried twice to obtain prefabricated activated carbon; the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 12:1.2:24:10; the stirring and mixing is carried out at a speed of 500 r / min for 45 min; the pH value is adjusted to 6.0; the drying is carried out at a temperature of 105°C for 4 h; the calcination is carried out at a heating rate of 10°C / min for heating at a temperature of 600°C for 1.5 h; the washing is carried out 3 times with deionized water; the secondary drying is carried out at a temperature of 105°C to a constant weight;

[0025] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tubular furnace for calcination, washed and dried for a second time to obtain the obtained product. The mixing is performed at a speed of 200 r / min for 20 minutes; the ultrasonic treatment is performed at a frequency of 400 W for 30 minutes; the drying is performed at a temperature of 110°C for 3 hours; the calcination is performed at a heating rate of 10°C / min for calcination at a temperature of 900°C for 2.0 hours; the washing is performed twice with deionized water; the secondary drying is performed at a temperature of 70°C for 10 hours; the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 3.0:1.0:15.

[0026] Example 2

[0027] A preparation process of nano-scale activated carbon comprises the following steps:

[0028] 1) washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; the sieving is grinding them through a 120-mesh sieve; and the drying is drying them at 65° C. for 5.8 hours;

[0029] 2) After stirring and mixing the rice husk particles, mercaptopropionic acid and deionized water, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried for a second time to obtain prefabricated activated carbon; the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 13:1.3:26:11; the stirring and mixing is performed at a speed of 520 r / min for 50 min; the pH value is adjusted to 6.1; the drying is performed at a temperature of 105°C for 4.5 h; the calcination is performed at a heating rate of 10°C / min for heating at a temperature of 620°C for 1.5 h; the washing is performed 3 times with deionized water; and the second drying is performed at a temperature of 105°C to a constant weight;

[0030] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tubular furnace for calcination, washed and dried for a second time to obtain the obtained product. The mixing is performed at a speed of 220r / min for 25min; the ultrasonic treatment is performed at a frequency of 420W for 34min; the drying is performed at a temperature of 112°C for 3.5h; the calcination is performed at a heating rate of 10°C / min for calcination at a temperature of 920°C for 2.5h; the washing is performed twice with deionized water; the secondary drying is performed at a temperature of 72°C for 10.5h; the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 3.5:1.2:16.

[0031] Example 3

[0032] A preparation process of nano-scale activated carbon comprises the following steps:

[0033] 1) washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; the sieving is grinding them through a 120-mesh sieve; and the drying is drying them at 70° C. for 6.5 hours;

[0034] 2) After stirring and mixing the rice husk particles, mercaptopropionic acid and deionized water, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried for a second time to obtain prefabricated activated carbon; the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 13.5:1.35:27:11.5; the stirring and mixing is performed at a speed of 550 r / min for 52 min; the pH value is adjusted to 6.2; the drying is performed at a temperature of 108°C for 4.5 h; the calcination is performed at a heating rate of 10°C / min for heating at a temperature of 650°C for 1.8 h; the washing is performed 3 times with deionized water; and the second drying is performed at a temperature of 108°C to a constant weight;

[0035] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tubular furnace for calcination, washed and dried for a second time to obtain the product. The mixing is performed at a speed of 250 r / min for 25 minutes; the ultrasonic treatment is performed at a frequency of 450 W for 38 minutes; the drying is performed at a temperature of 115°C for 3.5 hours; the calcination is performed at a heating rate of 10°C / min and heated to 940°C for 2.5 hours; the washing is performed twice with deionized water; the secondary drying is performed at a temperature of 75°C for 11 hours; the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 4:1.3:18.

[0036] Example 4

[0037] A preparation process of nano-scale activated carbon comprises the following steps:

[0038] 1) washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; the sieving is grinding them through a 120-mesh sieve; and the drying is drying them at 75° C. for 7 hours;

[0039] 2) After stirring and mixing the rice husk particles, mercaptopropionic acid and deionized water, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried for a second time to obtain prefabricated activated carbon; the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 14.2:1.42:28:12.2; the stirring and mixing is performed at a speed of 570 r / min for 55 min; the pH value is adjusted to 6.4; the drying is performed at a temperature of 109° C. for 4.8 h; the calcination is performed at a heating rate of 10° C. / min for calcination at a temperature of 675° C. for 1.8 h; the washing is performed 3 times with deionized water; and the second drying is performed at a temperature of 110° C. to a constant weight;

[0040] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tubular furnace for calcination, washed and dried for a second time to obtain the product. The mixing is performed at a speed of 275r / min for 28 minutes; the ultrasonic treatment is performed at a frequency of 475W for 41 minutes; the drying is performed at a temperature of 118°C for 3.8 hours; the calcination is performed at a heating rate of 10°C / min for calcination at a temperature of 960°C for 2.8 hours; the washing is performed twice with deionized water; the secondary drying is performed at a temperature of 78°C for 11.5 hours; the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 4.5:1.5:19.

[0041] Example 5

[0042] A preparation process of nano-scale activated carbon comprises the following steps:

[0043] 1) washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; the sieving is grinding them through a 120-mesh sieve; and the drying is drying them at 80° C. for 8 hours;

[0044] 2) After stirring and mixing the rice husk particles, mercaptopropionic acid and deionized water, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, the mixture is placed in a tubular furnace for calcination, and the mixture is washed and dried twice to obtain prefabricated activated carbon; the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 15:1.5:30:13; the stirring and mixing is performed at a speed of 600 r / min for 60 min; the pH value is adjusted to 6.5; the drying is performed at a temperature of 110° C. for 5 h; the calcination is performed at a heating rate of 10° C. / min for calcination at a temperature of 700° C. for 2.0 h; the washing is performed 3 times with deionized water; and the secondary drying is performed at a temperature of 110° C. to a constant weight;

[0045] 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tube furnace for calcination, washed and dried for a second time to obtain the product. The mixing is performed at a speed of 300 r / min for 30 minutes; the ultrasonic treatment is performed at a frequency of 500 W for 45 minutes; the drying is performed at a temperature of 120°C for 4 hours; the calcination is performed at a heating rate of 10°C / min and heated to 980°C for 3.0 hours; the washing is performed twice with deionized water; the secondary drying is performed at a temperature of 80°C for 12 hours; the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 5.0:1.6:20.

[0046] Comparative Example 1

[0047] Compared with Example 4, the difference is that the pH value is not adjusted in step 2) of Comparative Example 1, and the remaining preparation steps and parameters are the same.

[0048] Comparative Example 2

[0049] Compared with Example 4, the difference is that Comparative Example 2 does not use mercaptopropionic acid, and the remaining preparation steps and parameters are the same.

[0050] Comparative Example 3

[0051] Compared with Example 4, the difference lies in the order of adding zinc chloride in step 2);

[0052] Step 2): After the rice husk particles, zinc chloride, mercaptopropionic acid and deionized water are stirred and mixed, the pH value is adjusted and then stirred continuously, the mixture is placed in an oven for drying, and then placed in a tubular furnace for calcination, and then washed and dried twice to obtain prefabricated activated carbon;

[0053] The rest of the preparation steps and parameters were the same.

[0054] Comparative Example 4

[0055] Compared with Example 4, the difference is that zinc chloride is not used in Comparative Example 4, and the remaining preparation steps and parameters are the same.

[0056] Comparative Example 5

[0057] Compared with Example 4, the difference is that zirconium oxychloride octahydrate is not used in Comparative Example 5, and the other preparation steps and parameters are the same.

[0058] Comparative Example 6

[0059] Compared with Example 4, the difference is that in step 2) of Comparative Example 6, the mass ratio of rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 14.2:3:28:12.2, and the remaining preparation steps and parameters are the same.

[0060] Adsorption test

[0061] Weigh 0.02 g of activated carbon (Examples 1-5 and Comparative Examples 1-6) respectively, add 200 mL of 200 mg / L methylene blue, acid red 18 and Congo red test solution, and measure the organic matter concentration in the test solution after adsorption for 2 hours, and calculate the adsorption capacity;

[0062] The test results are shown in Table 1.

[0063] Table 1

[0064]

[0065]

[0066] From the test results in Table 1, it can be seen that compared with the activated carbon prepared in Comparative Examples 1-6, the nano-scale activated carbon prepared in Examples 1-5 of the present invention has significantly better adsorption effects on methylene blue, acid red 18 and Congo red than Comparative Examples 1-6.

[0067] From Examples 1-5 and Comparative Examples 1-6, combined with Table 1, comparative analysis shows that in the present invention, mercaptopropionic acid enters the interior of rice husk particles, and uses carboxyl groups to react with oxygen-containing functional groups of rice husk particles to form a cross-linked substance while allowing activated carbon to attach to mercapto groups. The cross-linked substance helps to form an activated carbon skeleton structure, increase the pore structure and specific surface area of ​​the activated carbon, and then under acidic conditions, the mercapto groups are more likely to release hydrogen ions, thereby increasing the coordination ability with zinc ions. When zinc chloride is initially added, the concentration of mercaptopropionic acid is higher, and more adsorption sites are provided, which can significantly increase the adsorption amount of zinc ions, so that more zinc chloride is attached to the rice husk particles to activate the activated carbon. agent, and zinc chloride acts as an activator, which can promote the removal of moisture in rice husk particles during high-temperature treatment, so that hydrogen and oxygen in the raw materials are released in the form of water vapor, thereby reducing the burning loss of the raw materials and helping to form activated carbon with a porous structure. After calcination of mercaptopropionic acid, a small part of the carbonized structure can fill the internal structure of the activated carbon, forming more microporous structures, while allowing more oxygen-containing functional groups and sulfur-containing functional groups to attach to the surface of the prefabricated activated carbon, which can promote the subsequent adsorption of zirconium ions. Finally, after calcination, zirconium oxide is dispersed on the surface of the activated carbon to form zirconium-based activated carbon, which can increase the number of pores in the activated carbon and improve the distribution of the pores, thereby improving its adsorption performance.

[0068] However, too much mercaptopropionic acid will lead to the number of free zinc ions in zinc chloride, thereby reducing the activation effect of zinc chloride during the calcination of activated carbon.

[0069] 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 process for preparing nano-grade activated carbon, characterized in that: The preparation process comprises the following steps: 1) Washing the rice husks, sieving them, and drying them in an oven to obtain rice husk particles; 2) After the rice husk particles, mercaptopropionic acid and deionized water are stirred and mixed, the pH value is adjusted, zinc chloride is added and stirred continuously, the mixture is placed in an oven for drying, and then placed in a tubular furnace for calcination, and after washing and secondary drying, a prefabricated activated carbon is obtained; 3) The prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water are mixed and then ultrasonically treated, placed in an oven for drying, placed in a tube furnace for calcination, washed and dried twice to obtain; In step 2), the drying is performed at 105-110°C for 4-5 hours; the secondary drying is performed at 105-110°C to constant weight; In step 2), the calcination is performed by heating to 600-700° C. at a heating rate of 10° C. / min for 1.5-2.0 h; In step 2), the pH value is adjusted to 6.0-6.5; In step 3), the drying is performed at 110-120°C for 3-4 hours; the secondary drying is performed at 70-80°C for 10-12 hours; In step 3), the calcination is performed by heating to a temperature of 900-980° C. at a heating rate of 10° C. / min for 2.0-3.0 h.

2. The process for preparing nano-grade activated carbon according to claim 1, characterized in that: In step 1), the screening is grinding through a 120-mesh sieve; and the drying is drying at 60-80° C. for 5-8 hours.

3. The process for preparing nano-grade activated carbon according to claim 1, characterized in that: In step 2), the stirring and mixing is performed at a speed of 500-600 r / min for 45-60 min; and the washing is performed 3 times with deionized water.

4. The process for preparing nano-grade activated carbon according to claim 1, characterized in that: In step 2), the mass ratio of the rice husk particles, mercaptopropionic acid, deionized water and zinc chloride is 12-15: 1.2-1.5：24-30：10-13。 5. The process for preparing nano-grade activated carbon according to claim 1, characterized in that: In step 3), the mixing is performed at a rotation speed of 200-300 r / min for 20-30 min; the ultrasonic treatment is performed at a frequency of 400-500 W for 30-45 min; and the washing is performed twice with deionized water.

6. The process for preparing nano-grade activated carbon according to claim 1, characterized in that: In step 3), the mass ratio of the prefabricated activated carbon, zirconium oxychloride octahydrate and deionized water is 3.0-5.0:1.0-1.6:15-20.

7. Application of nano-scale activated carbon prepared by the preparation process according to any one of claims 1 to 6 in the field of organic matter adsorption.

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