JP3030626B2 - Activated carbon made from leather waste and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a technology for utilizing leather waste, and more particularly to activated carbon obtained by using such leather waste as a raw material and a method for producing the same.

[0002]

2. Description of the Related Art As a raw material of a leather product, a raw leather is cut and divided into parts according to the use and processed into products such as shoes and bags, respectively. Leather waste such as waste is generated. Also, among the raw hides, so-called B-grade products and C-grade products, which have flaws or uneven color, are often left in stock, and may eventually be disposed of as waste material.
It is considered that leather waste is generated at a rate of 0%.

At present, the handling volume of natural leather in Japan, including imports from overseas and domestic ones, is estimated to be about 10 million m ² or more per year. Accordingly, the annual amount of leather waste material is also increased accordingly. Very large numbers. Such leather waste material depends on the properties of the material,
As with other waste, for example, no method has been found to recycle paper as pulp, or to separate and recover constituent metals from metal material products and reuse them as resources. Is being processed. In addition, since leather waste consists of animal skin tissue including protein, its treatment method is naturally limited, and it must ultimately be disposed of by incinerators. It is thought that there are various problems, and an appropriate processing method for that is required.

[0004] The present inventors have studied the appropriate treatment of leather waste material from such a situation, and as a result, have noticed that natural leather contains a considerable amount of carbon components. The possibility of carbonization in a carbonization furnace instead of combustion and incineration into activated carbon with useful applications was studied.

Activated carbon is used in many industrial fields mainly as an adsorbent obtained from coconut shells, coal, etc. In recent years, activated carbon has been used for environmental protection such as removal of pollutants in the air and water, as well as for deodorization, deodorization, and the like. Demand is increasing for applications such as water treatment, and it is widely used in industry and civil life. Most of activated carbon and its raw materials depend on imports from overseas, and the supply is not stable. If a large amount of leather waste that is currently unused and discarded or incinerated can be used as a raw material for such activated carbon, it will contribute to the reuse of natural resources and lower the production cost of activated carbon, as well as the use of leather waste itself. It is considered that waste disposal costs are reduced, and an increase in atmospheric carbon dioxide and the like due to incineration is suppressed correspondingly, which is significant from the viewpoint of environmental protection.

[0006] Incidentally, the adsorptive capacity, which is a characteristic property of activated carbon, differs depending on the material of the starting material, and the production method and conditions for effectively obtaining such adsorptive power also differ for each raw material. However, it has not been known at all heretofore to use animal leather waste material having significantly different properties from conventional materials such as coconut shells composed of vegetable fibers as a raw material for activated carbon. Therefore, when producing activated carbon using leather waste as a raw material, it is difficult to foresee the possibility of obtaining an activated carbon having sufficient adsorption capacity for practical use. There are issues that require new conditions to be established. The present inventors have repeated research and experiments on the production of activated carbon from leather waste, and have clarified the specific production steps and production conditions to complete the present invention.

[0007]

An object of the present invention is to carbonize waste leather in an inert gas at a temperature of 300 ° C. to 400 ° C., and then activate the gas at a temperature of 800 to 850 ° C. for 0.5 to 1 hour. The problem is solved by a method for producing activated carbon using leather waste as a raw material.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be further described with reference to preferred specific embodiments.

(Raw material) The activated carbon according to the present invention is obtained by carbonizing animal natural leather waste material. Examples of the leather waste material as a raw material include waste material obtained from a cutting process or the like in the production of leather products. Arbitrary materials such as leather waste materials generated from B and C grade products that have been altered by storage over time are used. The type of raw hide and the dyes and other chemicals used in the surface treatment of the product have little effect on the yield and adsorption performance of activated carbon as a carbide.

(Carbonization of Raw Material) Activated carbon using the waste leather material of the present invention as a raw material is produced by the steps shown in the following flow for carrying out the method of the present invention.

(Flow) Leather waste material → (Carburizing furnace) → Carbide → (Activating furnace) → Leather activated carbon Carbon dioxide gas in an inert gas; 300 ° C. or more Inert gas + carbon dioxide gas; Inert gas + steam; 800 Activated at ℃ to 850 ℃

First, 100 g of leather waste material as a raw material, for example, tannin tanned leather waste material is cut into small pieces as appropriate, and these are heat-treated in an inert gas stream in a carbonization furnace to carbonize. Thermogravimetric analysis showed that the leather waste material was thermally decomposed at a temperature of about 270 ° C., and the first peak (maximum decomposition rate) was generated at a temperature of 300 ° C. In order to carbonize leather waste in this way, carbonization proceeds at a lower temperature than in the process of producing activated carbon from ordinary raw materials.

In an actual experiment, in order to more clearly analyze the mechanism of activation in the next step, carbonization was carried out at a temperature (about 800 ° C.) at which volatiles in the raw material were almost completely removed in a nitrogen stream. After 24 hours, carbide was obtained in a yield of 24%. As described above, in a practical carbonization furnace, it is preferable to carbonize at a temperature of about 300 ° C. or more, particularly about 400 ° C., and carbonization is performed at a temperature considerably lower than the carbonization temperature when a conventional raw material is used. This is mainly due to the fact that the cytoplasm constituting the material is surrounded by cellulose cell walls in plant fibrous materials, whereas natural animal leather does not have such a clear cellulose outer wall and contains lipoprotein as the main component. This is probably due to the fact that it is covered only by the plasma membrane.

(Gas Activation) A predetermined amount of carbides from the raw material leather waste is then subjected to heat treatment in an activation furnace using an activation gas comprising a mixed gas of nitrogen gas and carbon dioxide gas as shown in the flow. Activated by Due to this activation, a large adsorption effective surface formed on the carbide and capillary condensation in the fine pores increase the adsorption amount and improve the adsorption performance.

In general, there are a gas activating method and a chemical activating method for activating a carbide when producing activated carbon. In the embodiment of the present invention, the gas activating method is employed. As the gas used for gas activation, a mixture of nitrogen and carbon dioxide gas was used. However, carbon dioxide gas may be used alone, or steam or the like may be used, and a mixture of these and an inert gas (nitrogen) may be used. May be used. The reaction with carbide when using carbon dioxide gas is basically represented by the following equation.

[0017]

Embedded image C + CO ₂ = 2CO-40.8 kcal

As shown in FIG. 1, which gives the results of thermal analysis in the activation of carbides, the carbides of leather decompose at a temperature of 750 ° C. or higher, a gasification reaction starts, and the decomposition ends at about 900 ° C. The reaction rate in this case depends on the gas concentration. In the embodiment of the present invention, the activation temperature is set to 800 ° C. (1H
r), 850 ° C. (0.5 Hr, 1 Hr) and 900 ° C.
(0.5 Hr, 1 Hr), and nitrogen and carbon dioxide are mixed and used as the activation gas (300/200:
(400/100 ml / min), the carbide sample was heated in an electric furnace at a rate of 10 ° C./min, and then maintained at a predetermined temperature to terminate the activation, and then cooled immediately.

(Adsorption performance and yield)
Yield (%) and adsorption performance (I) of activated carbon from leather waste obtained at an activation temperature of 00 to 900 ° C.
mg / Cg) is shown in Table 1 below.

[0020]

[Table 1]

As shown in Table 1, the amount of iodine adsorbed was affected by the temperature and time of the activation treatment, and the treatment at 800 ° C. to 900 ° C. gave generally good results in terms of adsorption capacity and yield. . Regarding the amount of adsorption, an iodine adsorption amount (mg / g) of about 500 to 600 mg per 1 g of activated carbon is obtained at a temperature of 800 ° C. to 850 ° C., and particularly as high as about 600 mg / g when treated at a temperature of 800 ° C. Adsorption capacity was obtained. Thus, it is effective to activate the leather carbide at a lower temperature than when vegetable fibrous is used as a raw material. At 900 ° C., the amount of adsorption is remarkably reduced. This is considered to be due to the collapse of micropores formed on the carbide surface due to excessive activation and the increase in the amount of ash that hinders adsorption.

Conventionally, charcoal has been used for deodorizing and deodorizing indoors and for removing and adsorbing impurities in water. However, the amount of adsorbed iodine of these ordinary charcoals is about 200 mg.
/ G. On the other hand, the adsorption capacity of activated carbon made from leather is about 2.5 to 3 times that of the activated carbon, which is practically sufficient for deodorizing and deodorizing the room, the storage space for furniture, and the surrounding products. doing.

[0023]

The activated carbon according to the embodiment of the present invention has been discarded before the use for recycling can not be found, and various kinds of activated carbon are used as raw materials by using leather waste material, which has a problem in incineration. Since useful activated carbon can be produced at a low cost, it has an excellent effect in terms of environmental protection and resource recycling.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of thermogravimetric analysis in the activation of carbide by the production method of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) Reference East German Patent 237298 (DD, A) USSR Patent Invention 1838235 (SU, A) Spanish Patent 2018379 (ES, A6) Entropie 98 (1981) p108-111 (58) Search Field (Int.Cl. ⁷ , DB name) C01B 31/08-31/14 CA (STN) WPI (DIALOG)

Claims (3)

(57) [Claims] 1. A method in which leather waste material is placed in an inert gas for 300 hours.
Carbonization at a temperature between 400C and 400C, then 800-850C
A method for producing activated carbon using leather waste material as a raw material, wherein gas activation is carried out at a temperature of 0.5 to 1 hour. 2. The method according to claim 1, wherein carbon dioxide gas is used for the gas activation treatment. 3. The method according to claim 1, wherein a mixture of an inert gas and carbon dioxide or steam is used for the gas activation treatment.