CN116924398B - A method for preparing activated carbon from urban solid domestic waste and its product - Google Patents

Abstract

The present invention proposes a method for preparing activated carbon from urban solid domestic waste and a product thereof, and belongs to the technical field of activated carbon preparation. The method of the present invention uses urban solid domestic waste as raw material, turns it into treasure, has low preparation cost, and realizes the reuse of solid waste. The urban solid domestic waste is compressed, dehydrated, carbonized and crushed to obtain raw material powder, the raw material powder is mixed with calcium oxide and aminosulfonic acid, and high-temperature activation treatment is performed under a protective atmosphere to obtain an activated product, the activated product is acid-leached, washed, solid-liquid separated, and dried to constant weight to prepare activated carbon. The method of the present invention is simple, the conditions are easy to control, and it is easier to promote production. The prepared activated carbon has a higher specific surface area.

Description

A method for preparing activated carbon from urban solid domestic waste and its product

Technical Field

The invention belongs to the technical field of activated carbon preparation, and in particular relates to a method for preparing activated carbon from urban solid domestic waste and a product thereof.

Background technique

Urban solid domestic waste mainly refers to solid waste generated in daily life or in activities that provide services for urban daily life. With the improvement of people's living standards, more and more urban solid domestic waste is generated every year. At present, there are three main ways to treat urban solid domestic waste: sanitary landfill, high-temperature composting and incineration. However, landfill treatment requires a large amount of land, and the harmful components in the garbage will also cause serious pollution to the atmosphere, soil and water sources, which not only damages the ecological environment, but also seriously endangers human health; composting treatment requires the garbage to be sorted and classified, and requires a high organic content of the garbage. In addition, composting treatment cannot reduce the amount of waste and still requires a large amount of land; incineration is to oxidize organic waste into inert gaseous substances and inorganic non-combustible substances under high temperature and sufficient oxygen supply to form stable solid residues. Due to the high degree of reduction in the incineration process, short treatment cycle, small footprint, and the widest range of applications.

For example, the patent with application number 201310098361.X discloses a method for preparing activated carbon using urban solid waste as raw material, which uses urban solid waste as raw material, pre-treats the raw material by drying and crushing, and then adds KOH for pyrolysis and calcination, thereby obtaining an activated carbon sample with a specific surface area of up to 646.32 ^m2 /g. Although the above method can successfully prepare biochar, the alkali activator (KOH) used in the activation process has an alkali-carbon ratio of 2:1-4:1. In the case of excessive use of the activator, the biochar-based material will be mechanically fractured during the activation process, and the etched pores will become new surfaces after being fractured, thereby causing the activator to lose the ability to continue etching the inside of the activated carbon in the existing pores, turning small pores into large pores, thereby causing a decrease in the total pore volume, and further reductions in the specific surface area and performance. Based on this, it is necessary to propose a new method for preparing activated carbon using urban solid domestic waste.

Summary of the invention

In order to solve the above technical problems, the present invention proposes a method for preparing activated carbon from urban solid domestic waste and its product.

To achieve the above object, the present invention proposes the following technical solutions:

One of the technical solutions of the present invention:

A method for preparing activated carbon from urban solid domestic waste comprises the following steps: compressing, dehydrating, carbonizing and crushing the urban solid domestic waste to obtain raw material powder; mixing the raw material powder with calcium oxide and aminosulfonic acid, subjecting the mixture to high-temperature activation treatment under a protective atmosphere to obtain an activated product; acid leaching the activated product, washing, solid-liquid separation, and drying the activated product to a constant weight to prepare activated carbon.

Furthermore, the temperature of the compression dehydration is 100°C-120°C, and the dehydration is performed to a water content of ≤15%. Urban solid domestic waste often has a high water content. By reducing the water content inside the waste through compression dehydration, dry carbon source powder can be obtained, which is more conducive to subsequent carbonization and activation.

Furthermore, the carbonization temperature is 200-400°C and the time is 1-4 hours. The carbonization process can form a pore structure on the surface of the raw material powder, which has a high specific surface area. The pore structure is more conducive to mixing with calcium oxide and aminosulfonic acid, so that the calcium oxide and aminosulfonic acid particles are combined with the raw material powder in an embedded manner.

Furthermore, the pulverizing is pulverizing to 100-200 meshes.

Furthermore, the mass ratio of the raw material powder to calcium oxide and aminosulfonic acid is 10:(4-6):(1-3). In the preparation process, the raw material powder is first mixed with calcium oxide, and the addition of calcium oxide can improve the mechanical strength of the raw material powder, so that the raw material does not mechanically break during the high-temperature activation treatment, and then mixed with aminosulfonic acid, so that the activated carbon raw material forms uniformly distributed mesopores after the high-temperature activation treatment, thereby increasing the specific surface area of the activated carbon.

Furthermore, the protective atmosphere is nitrogen or argon.

Furthermore, the temperature of the high temperature activation treatment is 500°C-750°C, and the activation time is 1h-2.5h. The high temperature activation treatment process will further form an activated carbon material with a multi-level pore structure of macropores, mesopores and micropores, further increasing the specific surface area of the activated carbon.

Furthermore, the acid used in the acid leaching process is hydrochloric acid and/or sulfuric acid, and the acid concentration is 0.5 mol/L-2 mol/L.

Furthermore, the acid leaching time is 30 minutes to 50 minutes. Excess calcium oxide and aminosulfonic acid are removed by acid leaching.

Furthermore, the washing is washing with water until neutrality.

The second technical solution of the present invention:

An activated carbon prepared by the above-mentioned method for preparing activated carbon from urban solid domestic waste.

Compared with the prior art, the present invention has the following advantages and technical effects:

(1) The raw materials used in the present invention are urban solid domestic waste, most of which are organic substances, and the carbon source is rich, which meets the objective conditions for preparing activated carbon. The present invention turns waste into treasure, has a low preparation cost, and realizes the recycling of solid waste.

(2) The method of the present invention is simple, the conditions are easy to control, and it is easier to promote production. The prepared activated carbon has a higher specific surface area and can be further used in various fields such as sewage treatment, catalyst carrier, and formaldehyde adsorption.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and/or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

The invention provides a method for preparing activated carbon from urban solid domestic waste, comprising the following steps: compressing, dehydrating, carbonizing and crushing the urban solid domestic waste to obtain raw material powder, mixing the raw material powder with calcium oxide and aminosulfonic acid, subjecting the mixture to high-temperature activation treatment under a protective atmosphere to obtain an activated product, acid leaching the activated product, washing, solid-liquid separation, and drying the activated product to a constant weight to prepare activated carbon.

Since urban solid domestic waste often has a high water content, the water content inside can be reduced by compression dehydration to obtain dry carbon source powder, which is more conducive to subsequent carbonization and activation. Based on this, in the preparation process of the embodiment of the present invention, the temperature of compression dehydration is 100°C-120°C, and the water content is dehydrated to ≤15%, such as 100°C, 110°C or 120°C, etc., but it is not limited to the listed values, and other values not listed within the numerical range are also applicable.

The carbonization process can form a pore structure on the surface of the raw powder, which has a high specific surface area. The pore structure is more conducive to mixing with calcium oxide and aminosulfonic acid, so that the calcium oxide and aminosulfonic acid particles are combined with the raw powder in an embedded manner. Based on this, in the preparation process of the embodiment of the present invention, the carbonization temperature is 200°C-400°C and the time is 1h-4h. For example, the carbonization temperature is 200°C, 300°C or 400°C, and the time is 1h, 2h or 4h, but it is not limited to the listed values. Other values not listed in the numerical range are also applicable.

In an embodiment of the present invention, the pulverizing is pulverizing to 100-200 meshes.

In the preparation process, the raw material powder is first mixed with calcium oxide. The addition of calcium oxide can improve the mechanical strength of the raw material powder and prevent the raw material from mechanically breaking during the high-temperature activation treatment. Then, it is mixed with aminosulfonic acid. After the high-temperature activation treatment, the activated carbon raw material forms uniformly distributed mesopores, thereby increasing the specific surface area of the activated carbon. In the embodiment of the present invention, as a preferred method, the mass ratio of the raw material powder to calcium oxide and aminosulfonic acid is 10: (4-6): (1-3).

In the embodiment of the present invention, the protective atmosphere is nitrogen or argon.

The high-temperature activation treatment process will further form an activated carbon material with a multi-level pore structure of macropores, mesopores, and micropores, further increasing the specific surface area of the activated carbon. Based on this, in the preparation process of the embodiment of the present invention, the temperature of the high-temperature activation treatment is 500°C-750°C, and the activation time is 1h-2.5h. For example, the temperature of the high-temperature activation treatment is 500°C, 600°C or 750°C, and the activation time is 1h, 2h or 2.5h, but it is not limited to the listed values, and other values not listed within the numerical range are also applicable.

In the embodiment of the present invention, the acid used in the acid leaching process is hydrochloric acid and/or sulfuric acid, the acid concentration is 0.5 mol/L-2 mol/L, and the acid leaching time is 30 min-50 min.

In the embodiment of the present invention, the washing is washing with water until neutral.

The urban solid domestic waste used in the embodiment of the present invention comes from a waste treatment plant in Kunming. The types of waste included include plastics, fabrics, waste paper, and food residues, but are not limited to the listed types of waste. The proportion of each type of waste is also unlimited, and the water content is ≈68%.

The calcium oxide used in the examples of the present invention was purchased from Lingshou County Xuanguang Mineral Products Processing Plant, and the aminosulfonic acid used was purchased from Jinan Qirui Tongda Chemical Co., Ltd.

The technical solution of the present invention is further illustrated by the following embodiments.

Example 1

The municipal solid domestic waste is compressed and dehydrated at 120°C to a water content of 10%, then carbonized at 300°C for 3h, and crushed to 100-200 mesh to obtain a raw powder, the raw powder is mixed with calcium oxide and aminosulfonic acid in a mass ratio of 10:5:2, and subjected to high-temperature activation treatment in a nitrogen atmosphere at a temperature of 600°C and an activation time of 1h to obtain an activated product, the activated product is acid-leached with 1 mol/L hydrochloric acid for 50min, washed with deionized water to neutrality, solid-liquid separation, and dried to constant weight to prepare activated carbon.

Example 2

The municipal solid domestic waste is compressed and dehydrated at 100°C to a water content of 15%, then carbonized at 200°C for 4h and crushed to 100-200 mesh to obtain a raw powder, the raw powder is mixed with calcium oxide and aminosulfonic acid in a mass ratio of 10:6:1, and subjected to high-temperature activation treatment in an argon atmosphere at a temperature of 750°C and an activation time of 2h to obtain an activated product, the activated product is acid-leached with 0.5mol/L hydrochloric acid for 30min, washed with deionized water to neutrality, solid-liquid separation, and dried to constant weight to prepare activated carbon.

Example 3

The municipal solid domestic waste is compressed and dehydrated at 110°C to a water content of 15%, then carbonized at 400°C for 1h, and crushed to 100-200 meshes to obtain a raw powder, the raw powder is mixed with calcium oxide and aminosulfonic acid in a mass ratio of 10:4:3, and subjected to high-temperature activation treatment in a nitrogen atmosphere at a temperature of 500°C and an activation time of 2.5h to obtain an activated product, the activated product is acid-leached with 2mol/L sulfuric acid for 40min, washed with deionized water to neutrality, solid-liquid separated, and dried to constant weight to prepare activated carbon.

Comparative Example 1

Same as Example 1, except that the compression and dehydration step is omitted:

The municipal solid domestic waste is carbonized at 300°C for 3h and crushed to 100-200 mesh to obtain a raw powder. The raw powder is mixed with calcium oxide and aminosulfonic acid in a mass ratio of 10:5:2, and subjected to high-temperature activation treatment in a nitrogen atmosphere at a temperature of 600°C and an activation time of 1h to obtain an activated product. The activated product is acid-leached with 1 mol/L hydrochloric acid for 50min, washed with deionized water to neutrality, separated into solid and liquid, and dried to constant weight to prepare activated carbon.

Comparative Example 2

Same as Example 1, except that the carbonization temperature is 150° C. and the time is 6 h.

Comparative Example 3

The same as Example 1, except that the addition of calcium oxide is omitted, and the raw material powder and aminosulfonic acid are mixed in a mass ratio of 10:2.

Comparative Example 4

The same as Example 1, except that the temperature of the high temperature activation treatment is 850° C. and the activation time is 4 h.

Performance Testing

The specific surface area and total pore volume of the activated carbon prepared in Examples 1-3 and Comparative Examples 1-4 were measured. The results are shown in Table 1. The measurement standards are as follows:

Specific surface area determination standard: GB/T 19587-2004

Total pore volume determination standard: GB/T 7702.20-1997

Table 1 Activated carbon performance test results of examples and comparative examples

It can be seen from the data in Table 1 that the activated carbon prepared in the embodiment of the present invention has a larger specific surface area and a higher total pore volume than the comparative example. The reasons are as follows: Comparative Example 1 omits the compression dehydration process. In the case of high water content of urban solid domestic waste, water forms water vapor at high temperature, resulting in untimely exhaust, thereby affecting the carbonization process; Comparative Example 2 changes the temperature and time of carbonization, resulting in the inability of the raw materials to form a carbon source with a stable structure; Comparative Example 3 omits the addition of calcium oxide. During the high-temperature activation treatment, the raw material is overheated inside, and the already formed pores are broken, preventing aminosulfonic acid from further etching the pores; Comparative Example 4 changes the temperature and time of the high-temperature activation treatment, which destroys the formation of the multi-level pore structure of the activated carbon.

The raw material used in the present invention is urban solid domestic waste, most of which contains organic matter, rich carbon source, and has the objective conditions for preparing activated carbon. The present invention turns waste into treasure, has low preparation cost, and realizes the reuse of solid waste. The method of the present invention is simple, the conditions are easy to control, and it is easier to promote production. The prepared activated carbon has a higher specific surface area and can be further used in various fields such as sewage treatment, catalyst carrier, and formaldehyde adsorption.

The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (7)

1. A method for preparing activated carbon from urban solid domestic waste, characterized in that it comprises the following steps: compressing, dehydrating, carbonizing and crushing the urban solid domestic waste to obtain a raw material powder, mixing the raw material powder with calcium oxide and aminosulfonic acid in sequence, subjecting the raw material powder to high temperature activation treatment under a protective atmosphere to obtain an activated product, acid leaching the activated product, washing, solid-liquid separation, and drying to constant weight to prepare activated carbon; The carbonization temperature is 200°C-400°C, and the time is 1h-4h; The temperature of the high temperature activation treatment is 500°C-750°C, and the activation time is 1h-2.5h; The mass ratio of the raw material powder to calcium oxide and aminosulfonic acid is 10:(4-6):(1-3). 2. The method for preparing activated carbon from urban solid domestic waste according to claim 1, characterized in that the temperature of the compression dehydration is 100°C-120°C, and the dehydration is performed to a water content of ≤15%. 3. The method for preparing activated carbon from urban solid domestic waste according to claim 1, characterized in that the crushing is to crush to 100 mesh-200 mesh. 4. The method for preparing activated carbon from urban solid domestic waste according to claim 1, characterized in that the acid used in the acid leaching process is hydrochloric acid and/or sulfuric acid. 5. The method for preparing activated carbon from urban solid domestic waste according to claim 4, characterized in that the acid leaching time is 30 min-50 min. 6. The method for preparing activated carbon from urban solid domestic waste according to claim 1, characterized in that the washing is washing with water until neutrality. 7. Activated carbon prepared by the method for preparing activated carbon from urban solid domestic waste according to any one of claims 1 to 6.