JPS6135286B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing activated carbon fibers by carbonizing and activating vegetable fibers using vegetable fibers as raw materials. Activated carbon fiber is an adsorbent that has recently attracted much attention because it is easier to handle than powdered activated carbon and has superior adsorption performance. Conventionally, activated carbon fibers have been manufactured using acrylic fibers as raw materials. In this conventional method, acrylic fibers are first oxidized in an oxidizing atmosphere at a temperature of about 200 to 300° C. while applying tension for about 2 to 20 hours to make them sufficiently flame resistant. Then, this flame-resistant fiber is treated in a steam atmosphere at a temperature of about 900 to 1000° C. for about 20 minutes to 3 hours, thereby obtaining an activated carbon fiber. However, in the conventional method, since acrylic fibers are used as raw materials, the flame resistance process takes a long time, and the activation process also takes a long time and has the disadvantage that the temperature also has to be high. In view of these circumstances, as a result of intensive research, the present inventors used vegetable fiber as the raw material fiber, and added a mixture of (1) zinc chloride, (2) ammonium chloride, boric acid, and nitric acid to the vegetable fiber. It has been found that by impregnating the activated carbon fibers with a solution containing at least one type of carbon fibers, followed by carbonization and activation, the yield of activated carbon fibers is dramatically improved, and the adsorption performance is also improved. Based on such knowledge, we have completed the present invention. That is, the present invention involves impregnating vegetable fibers with a solution containing at least one selected from the group consisting of (1) zinc chloride and (2) ammonium chloride, boric acid, and nitric acid, and then carbonizing and activating the solution. This is a method for producing activated carbon fiber characterized by the following. The vegetable fiber used in the present invention refers to all fibers made from plants, such as flocked fibers (e.g. cotton, kapok, bamboo cotton,
Panya, vegetable cotton, etc.), bast fibers (e.g., flax, hemp, jute, ramie, kenaf, mitsumata, etc.), leaf vein fibers (e.g., Manila hemp, New Zealand hemp, sisal hemp, hita fiber, etc.), fruit fibers (e.g. ; coconut, etc.), others (e.g. straw, straw, seaweed sugamo fiber,
(irritability, etc.), such as viscose rayon,
Examples include cellulose-based regenerated artificial fibers such as cuprammonium rayon, and cellulose-based semi-synthetic fibers such as acetate and acetate sulphur. These fibers may be in the form of fibers, or may be formed into a fiber structure such as a woven fabric, a nonwoven fabric, or a felt paper. 〓〓〓〓
In the present invention, the vegetable fiber is first impregnated with a solution containing (1) zinc chloride and (2) at least one selected from the group consisting of ammonium chloride, boric acid, and nitric acid. In the above solution, the amount of zinc chloride is about 5 to 40% by weight,
Particularly preferred is about 10 to 30% by weight. The amount of ammonium chloride, boric acid or nitric acid is preferably about 0.5 to 25% by weight, particularly about 2 to 20% by weight. The amount of zinc chloride impregnated into vegetable fiber is approximately 5 to 60% by weight,
Particularly preferred is about 10 to 30% by weight. If ammonium chloride is used, the amount is preferably about 5 to 25% by weight, especially about 10 to 20% by weight. If boric acid is used, it is preferably about 0.1 to 10% by weight, particularly about 0.5 to 5% by weight. If nitric acid is used, it is preferably about 0.1 to 10% by weight, especially about 0.5 to 5% by weight. The solution containing the above compound may be an aqueous solution or a solution containing alcohol or the like. Furthermore, in order to increase the solubility of zinc chloride and the like in water, for example, hydrochloric acid or the like may be added to the above solution. The amount is usually within about 5% by weight. Examples of means for impregnating the vegetable fibers with the solution include immersing the vegetable fibers in the solution and spraying the solution onto the vegetable fibers. Next, in the present invention, the vegetable fiber impregnated with the compound is carbonized and activated. The carbonization and activation temperature is preferably about 400 to 750°C, particularly about 450 to 650°C, and the time is about 0.25 to 2 hours, especially about 0.5 to 1
time is preferable. Carbonization and activation are usually performed under an inert gas atmosphere such as nitrogen gas, combustion exhaust gas such as heavy oil, light oil, and kerosene. The thus carbonized and activated vegetable fibers may be washed and dried by conventional methods, if necessary. According to the method of the present invention, the yield of activated carbon fibers is dramatically improved, so activated carbon fibers can be supplied at a much lower cost than conventional methods, and the resulting product has excellent adsorption performance. This is an extremely useful method industrially. EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples. Comparative Example 1 Commercially available cotton cloth (bleached) was mixed with 20% by weight of zinc chloride 0.2
After being immersed in an aqueous solution containing % by weight of hydrogen chloride for about 5 minutes, a rubber roller was used to uniformly support the squeeze chemical solution. The amount of zinc chloride supported was 0.35 g/g of the raw cloth. The raw material cloth carrying the chemical solution was wound around a 16-mesh stainless steel wire mesh roll and fired at a temperature of 600°C in a nitrogen stream for about 1/2 hour. In this way, activated carbon fiber A was obtained. The yield and adsorption power of the activated carbon fiber A were as shown in Table-1. Example 1 Activated carbon fiber B was prepared in the same manner as in Comparative Example 1 except that an aqueous solution containing 20% by weight of zinc chloride, 15.5% by weight of ammonium chloride, and 1% by weight of hydrogen chloride was supported.
was manufactured. The yield and adsorption power of the activated carbon fiber B were as shown in Table 1. The amount of chemicals supported was 0.4 g/g of the raw material cloth. Example 2 Commercial linen cloth was treated with 25% by weight zinc chloride and 2.5% by weight.
After being immersed in an aqueous solution containing 2% by weight of boric acid and 2% by weight of hydrogen chloride, the sample was dehydrated using a centrifuge to uniformly support the chemical solution. The amount of drug supported is 0.43
g/g - raw material cloth. The raw material cloth carrying the chemical solution was wound around a 16-mesh stainless steel wire mesh and fired at a temperature of 550° C. for 3/4 hours in a nitrogen stream to produce activated carbon fiber C. The yield and adsorption power of the activated carbon fiber C were as shown in Table-1. Example 3 Activated carbon fiber D was prepared in the same manner as in Example 2 except that an aqueous solution containing 25% by weight of zinc leadide, 12.5% by weight of ammonium chloride, 5% by weight of boric acid, and 1% by weight of hydrogen chloride was supported. was manufactured. The yield and adsorption power of the activated carbon fiber D were as shown in Table 1. The amount of chemicals supported was 0.47 g/g of the raw material cloth. Example 4 Activated carbon fiber E was produced in the same manner as in Comparative Example 1, except that an aqueous solution containing 15% by weight of zinc chloride, 2% by weight of nitric acid, and 1% by weight of hydrogen chloride was supported. The yield and adsorption power of the activated carbon fiber E were as shown in Table 1. The amount of chemicals supported was 0.25 g/g of the raw material cloth. 〓〓〓〓

[Table] Calculated from increase in amount.
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Claims (1)

[Claims] 1. It is characterized by impregnating vegetable fiber with a solution containing at least one selected from the group consisting of (1) zinc chloride and (2) ammonium chloride, boric acid, and nitric acid, and then carbonizing and activating it. Method for producing activated carbon fiber.