Activated carbon and activated carbon manufacturing method

Abstract

To provide activated carbon that can be obtained without going through an activation step and an activated carbon manufacturing method capable of producing the same.SOLUTION: This activated carbon 1 comprises silicon (for example, 1 wt.% to 25 wt.%). Furthermore, this activated carbon manufacturing method has a carbonization step SB for carbonizing a fabric 3 (for example, a base fabric of an airbag base fabric 4) made of polyester resin (for example, made of polyethylene terephthalate resin or polybutylene terephthalate resin) to which a silicon compound 2 (for example, silicon resin) is attached.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to activated carbon and a method for producing activated carbon capable of producing the same.

Background Art

[0002] Activated carbon is a porous carbon having a large specific surface area (for example, 300 m 2 / g or more). Activated carbon is generally obtained by carbonizing a raw material and subjecting it to an activation treatment (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the activation step for the activation treatment, equipment using gas (such as steam or carbon dioxide gas) or chemicals (such as alkali metal compounds) is required. Further, if a large amount of raw material is carbonized to obtain activated carbon, the equipment becomes large-scale.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide activated carbon that can be obtained without undergoing an activation step and a method for producing activated carbon that can produce the same.

Means for Solving the Problems

[0006] In order to achieve the above object, the activated carbon according to claim 1 contains silicon.

[0007] The activated carbon according to claim 2 contains 1% by weight to 25% by weight of silicon in the activated carbon according to claim 1.

[0008] The activated carbon according to claim 3 contains 2.5% to 10% by weight of silicon in the activated carbon according to claim 2.

[0009] The activated carbon according to claim 4 is in the activated carbon according to any one of claims 1 to 3, where x is the specific surface area (m 2 / g) and y is the pore diameter (Å), and it is in the region where y≧0.013x.

[0010] The method for producing activated carbon according to claim 5 does not go through an activation step.

[0011] The method for producing activated carbon according to claim 6 has a carbonization step of carbonizing a polyester resin added with a silicon compound.

[0012] The method for producing activated carbon according to claim 7 has a carbonization step of carbonizing a fabric made of a polyester resin to which a silicon compound is attached in the method for producing activated carbon according to claim 6.

[0013] The method for producing activated carbon according to claim 8 does not go through an activation step in the method for producing activated carbon according to claim 6 or 7.

[0014] The method for producing activated carbon according to claim 9 has a molding step of binding the activated carbon completed by the carbonization step or the pulverized activated carbon with a binder to form a molded body in the method for producing activated carbon according to claim 6 or 7.

[0015] The method for producing activated carbon according to claim 10 changes the pore diameter distribution of the activated carbon by changing the amount of heat in the carbonization step in the method for producing activated carbon according to any one of claims 5 to 7.

Advantages of the Invention

[0016] According to the activated carbon and the method for producing activated carbon of the present invention, activated carbon can be obtained without going through an activation step.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0018] Hereinafter, the mode for carrying out the present invention will be described. The activated carbon 1 according to the embodiment of the present invention contains silicon (Si). The silicon can be 1% to 25% by weight of the whole activated carbon 1, and preferably can be 2.5% to 10% by weight of the whole activated carbon 1. Since the activated carbon 1 contains silicon, it can be obtained without going through an activation process.

[0019] The activated carbon production method capable of producing such activated carbon 1 can be as follows. That is, this activated carbon production method S has a carbonization step SB (see FIGS. 1 and 2) of carbonizing a polyester resin to which a silicon compound 2 is added (more specifically, a fabric 3 made of a polyester resin to which the silicon compound 2 is attached). However, the form of the polyester resin to which the silicon compound 2 is added is not limited to a fabric, and it may be in the form of a film or an engineering plastic. The silicon compound 2 is a compound containing silicon, and includes, for example, a silicon resin (silicone resin). The polyester resin includes a polyethylene terephthalate resin, a polybutylene terephthalate resin, and the like. In the fabric 3 made of a polyester resin to which the silicon compound 2 is attached, the silicon component can be 0.2% by weight to 5% by weight of the whole (the total of the silicon compound 2 and the fabric 3), and preferably can be 0.5% by weight to 2% by weight of the whole.

[0020] In the production method of activated carbon 1, for example, as the fabric 3 made of a polyester resin to which the silicon compound 2 is attached, as shown in FIG. 2, an airbag fabric 4 in which a silicon resin 2A is coated on a base fabric 3A made of a polyester resin can be used. That is, the silicon resin 2A can be used as the silicon compound 2, and the base fabric 3A made of a polyester resin can be used as the fabric 3 made of a polyester resin. Here, the base fabric 3A made of a polyester resin is often made of a polyethylene terephthalate resin or a polybutylene terephthalate resin. Note that the silicon resin 2A is a thin film, but in FIG. 2, it is drawn thicker for illustration purposes.

[0021] The production method of activated carbon 1 using the airbag fabric 4 specifically has a recovery step SA and a carbonization step SB as shown in FIG. 1.

[0022] The recovery process SA is a process of recovering the airbag base fabric 4. The airbag base fabric 4 can be recovered from automobiles at the time of scrapping or from companies that process and manufacture the airbag base fabric. The recovery from automobiles at the time of scrapping can be done, for example, when a dismantler removes the airbag and sends the airbag components (metals such as inflators) to a designated trading place, by also sending the airbag base fabric separated from the airbag components, and recovering it from the designated trading place. Also, the recovery from companies that process and manufacture can be done by collecting the end materials generated in the process of cutting and sewing into a bag shape or the like in the company and recovering it.

[0023] The carbonization process SB is a process of carbonizing the recovered airbag base fabric 4 to generate a large number of pores. The airbag base fabric 4 may be carbonized in the recovered state, or may be shredded and then carbonized. Also, it may be fluffed and then carbonized.

[0024] In the carbonization process SB, the base fabric 3A made of polyester resin is heated (for example, heated to 600 °C to 900 °C) in an oxygen-free state while the thin film of the silicon resin 2A remains attached, and is carbonized. At this time, although the silicon resin 2A is considered to be modified or decomposed, its silicon component promotes the foaming of the base fabric 3A that is being carbonized and the generation of a large number of pores. This is considered to be because the silicon component acts catalytically.

[0025] What is thus completed by the carbonization process SB is activated carbon 1, which is a porous carbon having a large specific surface area of about 300 m 2 / g or more (see Figure 6). Therefore, by this carbonization process SB, activated carbon 1 having a sufficiently large specific surface area can be obtained without going through the subsequent activation process. As a result, reduction in manufacturing cost and equipment cost is expected. The activated carbon 1 thus completed is non-activated activated carbon that does not go through the activation process, but in cases where it is desired to adjust the pore size distribution, etc., it may be made to go through the subsequent activation process. Even in that case, a simple activation treatment will suffice.

[0026] In addition, the activated carbon 1 can change the pore size distribution by changing the amount of heat (such as carbonization temperature or carbonization time) in the carbonization step SB (see the following experiment). For example, when the molded body formed by the activated carbon 1 is an adsorption filter, it is possible to change the pore size distribution by changing the amount of heat in the carbonization step SB according to the adsorption function for the substance mainly adsorbed.

[0027] Subsequent to the carbonization step SB, a molding step SC may be performed in which part or all of the activated carbon 1 completed by the carbonization step SB is bound with a binder 5 to form a molded body 6 (see FIG. 1). The molded body 6 is, for example, an adsorption filter or a polar electrode of an electric double layer capacitor. As the binder 5, a fibrous binder or the like can be used when the molded body 6 is an adsorption filter, and a PVdF-based resin or the like can be used when the molded body 6 is a polar electrode of an electric double layer capacitor.

[0028] In the molding step SC, it is possible to use the activated carbon 1 completed by the carbonization step SB as it is, or it is also possible to use the pulverized one. Here, since the activated carbon 1 completed by the carbonization step SB is only slightly stuck together as a whole and is easily pulverized, the force applied to the activated carbon 1 for pulverization can be very small. For example, it can be pulverized by stirring.

[0029] In this way, if the activated carbon 1 does not need to go through the subsequent activation step, a large amount of raw material (airbag base fabric 4) can be easily and efficiently processed.

[0030] Next, the experiments conducted by the inventors of the present application will be described. FIG. 3(a) is a photograph of the activated carbon 1 in a state where the recovered airbag base fabric 4 (specifically, a part thereof) is heated so that the temperature rises at about 3 ° C. / min in an oxygen-free state and held at 700 ° C. for about 10 minutes to be carbonized. The airbag base fabric 4 is obtained by coating a base fabric 3A made of a polyester resin (specifically, a polyethylene terephthalate resin) with a silicon resin 2A.

[0031] Here, the activated carbon 1 in the state after carbonization is in a brittle sponge-like form. Fig. 3(b) is an enlarged photograph of a part of the activated carbon 1 in Fig. 3(a). The activated carbon 1 contains many thin flakes with a thickness on the micron order, and a large number of pores are generated, and it can be seen that it is in a state where it can be easily pulverized. Fig. 3(c) is a photograph of the activated carbon 1 in the state of Fig. 3(a) being pulverized by applying a small force.

[0032] Fig. 4 is a photograph of the state where a PET bottle chip (a chip made of polyethylene terephthalate) is carbonized under the same conditions as above for comparison with Fig. 3. Since the PET bottle chip is not coated with a silicone resin, it becomes a hard lump when carbonized, and a pulverizing machine is required for pulverization, and also an activation treatment is required thereafter to make it activated carbon.

[0033] When extracted and measured from different parts of the activated carbon 1 in the state of Fig. 3(a), the pore diameters of the activated carbon 1 have a distribution as shown by curves a, b, and c in Fig. 5. The vertical axis is the pore diameter distribution (unit: cc / g / Å), and the horizontal axis is the pore diameter (unit: Å). The distributions of the pore diameters of curves a, b, and c have changed due to the change in the amount of heat (such as carbonization temperature or carbonization time) applied to each part. In curves a, b, and c, the central pore diameters are about 26 Å, about 10 Å, and about 7.5 Å or less, respectively. The pore diameter and its distribution were measured using the QSDFT method.

[0034] For example, the measurement results of the adsorption performance of a sample taken from the state shown by curve c are as shown in Table 1 below. This sample has a large specific surface area of 358.8 m 2 / g and a small pore diameter of 7.23 Å. This sample can adsorb iodine and can adsorb toluene. It may also be able to adsorb carbon dioxide and methane. The specific surface area was measured using the BET multipoint method by nitrogen gas adsorption, and both iodine adsorption and toluene adsorption were measured using the JIS method.

[0035]

Table 1

[0036] Figure 6 is a graph showing the relationship between the pore diameter and specific surface area of activated carbon 1 after carbonization in other experiments. The measured values indicated by ● in the figure are those obtained by manufacturing and measuring a large number of activated carbons 1 in a state where the recovered airbag base fabric 4 (specifically, a part thereof) was heated to 700°C in an oxygen-free state and carbonized. Also, the measured values indicated by ○ in the figure are those obtained by subjecting some of the measured values indicated by ● to an activation treatment. Note that the measured values in the region indicated by B in the figure are the measured values extracted from those manufactured with a larger amount of heat (such as carbonization time) during carbonization than the measured values in the region indicated by A.

[0037] From Figure 6, it can be seen that the measured values of the activated carbon 1 without the activation treatment are in the region of y≧ax (where a = 0.013), where x is the specific surface area (m 2 / g) and y is the pore diameter (Å). If the activation treatment is performed, it can be seen that the measured values move to the region of y < ax.

[0038] As described above, the method for manufacturing activated carbon according to the embodiment of the present invention has been described. However, the present invention is not limited to those described in the embodiment, and various design changes can be made within the scope of the matters described in the claims.

Explanation of Reference Numerals

[0039] 1 Activated carbon 2 Silicon compound 2A Silicon resin 3 Fabric made of polyester resin 3A Base fabric made of polyester resin 4 Airbag base fabric 5 Binder 6 Formed body SA Recovery step SB Carbonization step SC Forming step

Claims

1. Activated carbon containing silicon.

2. The activated carbon according to Claim 1, which contains 1% to 25% by weight of silicon.

3. The activated carbon according to Claim 2, which contains 2.5% to 10% by weight of silicon.

4. In the activated carbon according to any one of claims 1 to 3, when x is the specific surface area (m ２ / g) and y is the pore diameter (Å), the activated carbon in the region where y ≧ 0.013x.

5. A method for manufacturing activated carbon without an activation process.

6. A method for manufacturing activated carbon having a carbonization process of carbonizing a polyester resin to which a silicon compound is added.

7. The method for manufacturing activated carbon according to Claim 6, which has a carbonization process of carbonizing a fabric made of a polyester resin to which a silicon compound is adhered.

8. The method for manufacturing activated carbon according to Claim 6 or 7, which is a method for manufacturing activated carbon without an activation process.

9. In the method for manufacturing activated carbon according to Claim 6 or 7, a molding process of binding the activated carbon completed by the carbonization process or the activated carbon obtained by pulverizing the same with a binder to form a molded body.

10. In the method for manufacturing activated carbon according to any one of Claims 5 to 7, a method for manufacturing activated carbon in which the pore size distribution of the activated carbon is changed by changing the amount of heat in the carbonization process.

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