Activated carbon-supported active particle composite materials, preparation methods and applications

Abstract

This invention relates to an activated carbon-supported activated particle composite material, its preparation method, and its application, belonging to the field of activated carbon preparation technology. The composite material is prepared from straw as raw material through secondary carbonization, potassium hydroxide modification, and composite activation metal. During use, this material is added simultaneously with persulfate, exhibiting excellent removal effects on wastewater, especially organic matter. In this invention, the potassium hydroxide treatment of the straw increases the specific surface area of ​​the activated carbon. The activation metal contains compounds of Fe and Mn, which have a good activation effect on persulfate. The synergistic effect of activated carbon activation and activation metal activation significantly enhances the activation of persulfate. Furthermore, the activation metal is coated with an organic carbon skeleton shell structure, reducing secondary pollution, while the porous structure on the surface of the coating enhances its adsorption performance.

Description

Technical Field

[0001] This invention belongs to the field of activated carbon preparation technology, specifically, it relates to an activated carbon-supported active particle composite material, its preparation method and its application. Background Technology

[0002] In recent years, advanced oxidation processes based on sulfate radicals have received increasing attention due to their high degradation capacity and adaptability to emerging pollutants. Persulfate advanced oxidation refers to the activation of persulfates through various means to generate sulfate radicals (SO42-). -· It uses a variety of active species, primarily SO4, to degrade various pollutants in water. -· It has a redox potential comparable to ·OH, but also a longer half-life, allowing for more stable contact with pollutants in the system. Compared to ·OH, which has stringent pH requirements, SO42-... -· It has stronger adaptability and can achieve efficient removal of pollutants in a wider pH range.

[0003] Ordinary activated carbon has limited effectiveness in removing organic matter from wastewater, and there is an urgent need for activated carbon with better organic matter treatment performance. Summary of the Invention

[0004] This invention relates to an activated carbon-supported activated particle composite material, its preparation method, and its application, belonging to the field of activated carbon preparation technology. The composite material is prepared from straw as raw material through secondary carbonization, potassium hydroxide modification, and composite activation metal. During use, this material is added simultaneously with persulfate, exhibiting excellent removal effects on wastewater, especially organic matter. In this invention, the potassium hydroxide treatment of the straw increases the specific surface area of ​​the activated carbon. The activation metal contains compounds of Fe and Mn, which have a good activation effect on persulfate. The synergistic effect of activated carbon activation and activation metal activation significantly enhances the activation of persulfate. Furthermore, the activation metal is coated with an organic carbon skeleton shell structure, reducing secondary pollution, while the porous structure on the surface of the coating enhances its adsorption performance.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing an activated carbon-supported active particle composite material includes the following steps:

[0007] (1) Wash the straw with water, dry it, and crush it;

[0008] (2) Carbonize the crushed straw once and cool it to room temperature;

[0009] (3) Soak the carbonized straw in potassium hydroxide solution and then dry it;

[0010] (4) The soaked straw is carbonized a second time to obtain carbonized straw;

[0011] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic aldehyde and acetic acid, mix evenly, let stand, then add carbonized straw, mix evenly, and dry to obtain activated carbon-supported active particle composite material.

[0012] As a preferred embodiment of the present invention, the carbonization in (2) is carbonization at 280-320℃ for 1.5-2.5h.

[0013] As a preferred embodiment of the present invention, the mass concentration of the potassium hydroxide solution in (3) is 25-35%, and the mass ratio of straw to KOH after one carbonization is controlled to be 1:2.8-3.2.

[0014] As a preferred embodiment of the present invention, the secondary carbonization described in (4) is carbonization at 680-720℃ for 1.5-2.5h.

[0015] As a preferred embodiment of the present invention, the activated metal in (5) is obtained by the following operation: preparing Fe 3+ Concentration, Mn 2+ Metal ion solutions with a concentration of 0.5 mol / L were added to egg white and stirred until a homogeneous mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was heated to 400°C and calcined for 2 hours. After cooling, it was ground into powder to obtain activated metal.

[0016] As a preferred embodiment of the present invention, the ratio of the activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw in (5) is 18-22 mg: 8-10 mL: 11-13 mg: 1 mg: 10-15 g.

[0017] In a preferred embodiment of the present invention, the volume ratio of the metal ion solution to the egg white is 1:2-3.

[0018] The activated carbon-supported active particle composite material prepared by the above method.

[0019] The application of the above-mentioned activated carbon-supported activated particle composite material in wastewater purification refers to the simultaneous addition of the activated carbon-supported activated particle composite material and persulfate to the wastewater, wherein the dosage of the persulfate is 2-4 mmol / L and the dosage of the activated carbon-supported activated particle composite material is 3-5 g / L.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention provides an activated carbon-supported activated particle composite material, which is made from straw as raw material through secondary carbonization, potassium hydroxide modification, and composite activation metal. This material is added simultaneously with persulfate during use and has excellent removal effect on wastewater, especially organic matter in wastewater.

[0022] 2. In this invention, after the straw is treated with potassium hydroxide, the potassium ions enter the carbon lattice, which corrodes and dissolves part of the carbon skeleton in the straw char, resulting in an increase in microporosity. This increases the specific surface area of ​​the activated carbon, as well as the pore volume and pore size, and can also provide more reaction sites for the activation of persulfate.

[0023] 3. In this invention, an activating metal is provided, which contains compounds of two metals, Fe and Mn, and has a good activation effect on persulfate. At the same time, the activated carbon obtained from straw retains abundant functional groups after treatment with potassium hydroxide. The synergistic effect of activated carbon activation and activated metal activation significantly improves the activation of persulfate.

[0024] 4. In this invention, an organic carbon skeleton shell structure is formed by coating the activated metal. While ensuring efficient catalytic effect, it reduces the leaching of Fe and Mn. After coating, ions are basically not leached, reducing secondary pollution. At the same time, the porous structure on the surface of the coating structure enhances its adsorption performance, which is more conducive to the contact between pollutants and materials and enhances the reaction effect. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] An activated carbon-supported active particle composite material is prepared by the following method:

[0028] (1) Wash the straw with water, dry it at 60℃, and then crush it;

[0029] (2) The crushed straw was carbonized at 280℃ for 1.5h and then cooled to room temperature;

[0030] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 60°C;

[0031] The mass concentration of the potassium hydroxide solution is 25%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:2.8.

[0032] (4) The soaked straw is carbonized again at 680℃ for 1.5h to obtain carbonized straw;

[0033] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic aldehyde and acetic acid and mix evenly. Let stand for 1 hour, then add carbonized straw and mix evenly. Dry at 60°C to obtain activated carbon-supported active particle composite material.

[0034] The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw is 18 mg: 8 mL: 11 mg: 1 mg: 10 g.

[0035] The activated metal is obtained through the following operation: preparing Fe 3+ Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was added to egg white, with a volume ratio of 1:2 between the metal ion solution and egg white. The mixture was stirred vigorously until a homogeneous mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was calcined in a muffle furnace at a programmed temperature of 400°C for 2 hours. After cooling, the mixture was ground into powder to obtain the activated metal.

[0036] Example 2

[0037] An activated carbon-supported active particle composite material is prepared by the following method:

[0038] (1) Wash the straw with water, dry it at 65℃, and then crush it;

[0039] (2) The crushed straw was carbonized at 290℃ for 1.8h and then cooled to room temperature;

[0040] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 65°C;

[0041] The mass concentration of the potassium hydroxide solution is 28%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:2.9.

[0042] (4) The soaked straw is carbonized again at 690℃ for 1.8h to obtain carbonized straw;

[0043] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic methyl ester and acetic acid and mix evenly. Let stand for 1 hour, then add carbonized straw and mix evenly. Dry at 65°C to obtain activated carbon-supported active particle composite material.

[0044] The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw is 19 mg: 8.5 mL: 11.5 mg: 1 mg: 11 g;

[0045] The activated metal is obtained through the following operation: preparing Fe 3+ Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was added to egg white, with a volume ratio of 1:2.2. The mixture was stirred vigorously until a homogeneous mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was calcined in a muffle furnace at a programmed temperature of 400°C for 2 hours. After cooling, it was ground into powder to obtain the activated metal.

[0046] Example 3

[0047] An activated carbon-supported active particle composite material is prepared by the following method:

[0048] (1) Wash the straw with water, dry it at 70℃, and then crush it;

[0049] (2) Carbonize the crushed straw at 300℃ for 2 hours and then cool it to room temperature;

[0050] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 70°C;

[0051] The mass concentration of the potassium hydroxide solution is 30%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:3.0.

[0052] (4) The soaked straw is carbonized again at 700℃ for 2 hours to obtain carbonized straw;

[0053] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic methyl ester and acetic acid and mix evenly. Let stand for 1 hour, then add carbonized straw and mix evenly. Dry at 70°C to obtain activated carbon-supported active particle composite material.

[0054] The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid, and carbonized straw is 20 mg: 9 mL: 12 mg: 1 mg: 12.5 g.

[0055] The activated metal is obtained through the following operation: preparing Fe 3+Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was added to egg white, with a volume ratio of 1:2.5 between the metal ion solution and egg white. The mixture was stirred vigorously until a homogeneous mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was calcined in a muffle furnace at a programmed temperature of 400°C for 2 hours. After cooling, it was ground into powder to obtain the activated metal.

[0056] Example 4

[0057] An activated carbon-supported active particle composite material is prepared by the following method:

[0058] (1) Wash the straw with water, dry it at 75℃, and then crush it;

[0059] (2) The crushed straw was carbonized at 310℃ for 2.2 hours and then cooled to room temperature;

[0060] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 75°C;

[0061] The mass concentration of the potassium hydroxide solution is 32%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:3.1.

[0062] (4) The soaked straw is carbonized again at 710℃ for 2.2h to obtain carbonized straw;

[0063] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic methyl ester and acetic acid and mix evenly. Let stand for 1 hour, then add carbonized straw and mix evenly. Dry at 75°C to obtain activated carbon-supported active particle composite material.

[0064] The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw is 21 mg: 9.50 mL: 12.4 mg: 1 mg: 14 g;

[0065] The activated metal is obtained through the following operation: preparing Fe 3+ Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was added to egg white at a volume ratio of 1:2.8, and the mixture was stirred vigorously until a homogeneous mixture was formed. The mixture was then heated in an 80°C water bath for 2 hours to form a gel, and allowed to stand for 4 hours before drying. Finally, the gel was calcined in a muffle furnace at a programmed temperature of 400°C for 2 hours, cooled, and ground into powder to obtain the activated metal.

[0066] Example 5

[0067] An activated carbon-supported active particle composite material is prepared by the following method:

[0068] (1) Wash the straw with water, dry it at 80℃, and then crush it;

[0069] (2) The crushed straw was carbonized at 320℃ for 2.5 hours and then cooled to room temperature;

[0070] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 80°C;

[0071] The mass concentration of the potassium hydroxide solution is 35%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:3.2.

[0072] (4) The soaked straw is carbonized again at 720℃ for 2.5h to obtain carbonized straw;

[0073] (5) Add 1,4-dioxane to the activated metal, then add pyromellitic methyl ester and acetic acid and mix evenly. Let stand for 1 hour, then add carbonized straw and mix evenly. Dry at 80°C to obtain activated carbon-supported active particle composite material.

[0074] The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw is 22 mg: 10 mL: 13 mg: 1 mg: 15 g.

[0075] The activated metal is obtained through the following operation: preparing Fe 3+ Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was added to egg white, with a volume ratio of 1:3 between the metal ion solution and egg white. The mixture was stirred vigorously until a homogeneous mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was calcined in a muffle furnace at a programmed temperature of 400°C for 2 hours. After cooling, it was ground into powder to obtain the activated metal.

[0076] Comparative Example 1

[0077] An activated carbon-supported active particle composite material, which, compared with Example 5, does not undergo potassium hydroxide impregnation treatment, but is otherwise the same as Example 5.

[0078] Comparative Example 2

[0079] An activated carbon-supported active particle composite material, compared with Example 5, does not undergo a single carbonization, but is otherwise the same as Example 5.

[0080] Comparative Example 3

[0081] An activated carbon-supported active particle composite material, compared with Example 5, does not involve coating the activated metal, and includes the following operations:

[0082] (1) Wash the straw with water, dry it at 80℃, and then crush it;

[0083] (2) The crushed straw was carbonized at 320℃ for 2.5 hours and then cooled to room temperature;

[0084] (3) The straw after one carbonization is soaked in potassium hydroxide solution and then vacuum dried at 80°C;

[0085] The mass concentration of the potassium hydroxide solution is 35%, and the mass ratio of the straw after primary carbonization to KOH in the potassium hydroxide solution is controlled to be 1:3.2.

[0086] (4) The soaked straw is carbonized again at 720℃ for 2.5h to obtain carbonized straw;

[0087] (5) Preparation of Fe 3+ Concentration, Mn 2+ A metal ion solution with a concentration of 0.5 mol / L was prepared. Carbonized straw was added to the metal ion solution and stirred vigorously until a homogeneous mixture was formed. After standing and aging for 4 hours, the mixture was dried and then calcined in a muffle furnace at a programmed temperature of 400℃ for 2 hours. After cooling, the mixture was ground into powder to obtain an activated carbon-supported active particle composite material.

[0088] Comparative Example 4

[0089] An activated carbon-supported active particle composite material, compared with Example 5, does not have the addition of activated metal or its coating, but is otherwise the same as Example 5.

[0090] The composite materials obtained in Examples 1-5 and Comparative Examples 1-4 were subjected to the following tests:

[0091] Experimental Example 1: Specific Surface Area Test

[0092] The specific surface area of ​​the composite material of the sample was tested using a specific surface area meter, and the results are shown in Table 1.

[0093] Experimental Example 2: Adsorption of Organic Matter by Synergistic Persulfate

[0094] At room temperature, the same batch of raw water with a CODcr of 118.24 mg / L was taken, the dosage of persulfate was 2 mmol / L, and the dosage of the activated carbon-supported active particle composite material was 3 g / L. The reaction was carried out for 60 min, and samples were taken and the CODcr was detected. The CODcr removal rate was calculated, and the results are shown in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] As shown in Table 1, the activated carbon-supported activated particle composite material provided by the present invention has good specific surface area and high CODcr removal rate in Examples 1-5. However, the specific surface area of ​​Comparative Examples 1 and 2 is significantly lower than that of the Examples, and the CODcr removal rate is also slightly lower. Comparative Example 3 has no significant change in specific surface area and CODcr compared with the Examples, and the removal rate is also good. However, secondary pollution of Fe and Mn was generated in the wastewater. Comparative Example 4 has no significant change in specific surface area and CODcr compared with the Examples, but the removal rate is significantly lower.

[0099] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a composite material of activated carbon supported on activated particles, characterized in that, The preparation method includes the following operations: (1) Wash the straw with water, dry it, and crush it; (2) Carbonize the crushed straw once and cool it to room temperature; (3) Soak the carbonized straw in potassium hydroxide solution and then dry it; (4) The soaked straw is carbonized a second time to obtain carbonized straw; (5) Add 1,4-dioxane to the activated metal, then add pyromellitic methyl ester and acetic acid, mix evenly, let stand, then add carbonized straw, mix evenly, and dry to obtain activated carbon-supported active particle composite material. The activated metal mentioned in (5) is obtained by the following operation: preparing Fe 3+ Concentration, Mn 2+ Metal ion solutions with a concentration of 0.5 mol / L were added to egg white and stirred until a mixture was formed. The mixture was heated in an 80°C water bath for 2 hours to form a gel, and then allowed to stand for 4 hours before drying. Finally, the mixture was heated to 400°C and calcined for 2 hours. After cooling, it was ground into powder to obtain activated metal.

2. The method for preparing an activated carbon-supported active particle composite material according to claim 1, characterized in that, (2) The carbonization process described is carbonization at 280-320℃ for 1.5-2.5h.

3. The method for preparing an activated carbon-supported active particle composite material according to claim 1, characterized in that, (3) The mass concentration of the potassium hydroxide solution is 25-35%, and the mass ratio of straw to KOH after one carbonization is controlled to be 1:2.8-3.

2.

4. The method for preparing an activated carbon-supported active particle composite material according to claim 1, characterized in that, (4) The secondary carbonization is carbonization at 680-720℃ for 1.5-2.5h.

5. The method for preparing an activated carbon-supported active particle composite material according to claim 1, characterized in that, The ratio of activated metal, 1,4-dioxane, trimethylolpropionate, acetic acid and carbonized straw used in (5) is 18-22 mg: 8-10 mL: 11-13 mg: 1 mg: 10-15 g.

6. The method for preparing an activated carbon-supported active particle composite material according to claim 5, characterized in that, The volume ratio of the metal ion solution to egg white is 1:2-3.

7. An activated carbon-supported active particle composite material prepared by the preparation method according to any one of claims 1-6.

8. The application of the activated carbon-supported activated particle composite material as described in claim 7 in wastewater purification, characterized in that, The application refers to the simultaneous addition of the activated carbon-supported activated particle composite material and persulfate to wastewater, wherein the dosage of the persulfate is 2-4 mmol / L and the dosage of the activated carbon-supported activated particle composite material is 3-5 g / L.

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