Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Inorganic carbon containing
Patent
1980-02-22
1983-10-11
Konopka, P. E.
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Inorganic carbon containing
264 292, 4234474, 4234475, 4234479, 502181, C01B 3112, B01J 2020, D01F 912
Patent
active
044091257
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a method for producing activated fibrous carbon with the use of vegetable fibers as a raw material.
2. Background Art
Activated fibrous carbon is easier to handle and is provided with the improved adsorption capacity, as compared with powdered carbon, and has recently been drawing greater attraction as the adsorbent.
Activated fibrous carbon has been conventionally produced using acrylic fibers as the raw material. In such a conventional process, acrylic fibers, while tension is being applied, are firstly subjected to oxidation-treatment under an oxidizing atmosphere at a temperature of about 200.degree. to 300.degree. C. for a period of time as long as 10 to 20 hours to make them adequately flame retardant. The thus treated materials are then burned in an atmosphere of steam at increased temperature up to about 900.degree. to 1000.degree. C. for a period of about 20 minutes to 3 hours, resulting in activated fibrous carbon.
Yet, the process with the use of acrylic fibers as raw material is accompanied with the defects that increased length of time is required in the step of flame-resistance treatment and that the period of time and temperature for the step of activation must be prolonged and elevated.
There is also known a method for producing activated fibrous carbon comprising immersing cellulose based fibers such as cotton and rayons in an aqueous solution of zinc chloride, and effecting carbonization and activation at 500.degree. to 800.degree. C. after drying. However, it has been proven that the activated fibrous carbon is not necessarily satisfactory in the flexibility.
A thorough and extensive research study carried out by the inventors in view of these circumstances has shown that carbonization and activation of vegetable fibers in the presence of at least a member selected from the group consisting of ammonium salts of inorganic acids, boric acid and nitric acid and a particular ratio of zinc chloride lead to a remarkable increase in the yield of the activated fibrous carbon, along with the improved adsorption capacity. It has been found out, in particular, that the activated fibrous carbon with an increased degree of flexibility can be produced by carbonizing vegetable fibers in the presence of at least a member selected from the group consisting of ammonium salts of inorganic acids, boric acid and nitric acid, and activating then the carbonized materials in the presence of zinc chloride of a specific ratio. Further, the yield for the activated fibrous carbon has been proven to be increased remarkably.
On the basis of these findings, the present invention has been completed.
DISCLOSURE OF THE INVENTION
The present invention relates to a process for producing activated fibrous carbon characterized by carbonizing and activating vegetable fibers in the presence of at least a member selected from the group consisting of ammonium salts of inorganic acids, nitric acid and boric acid and zinc chloride of about 5 to 80 parts by weight for 100 parts by weight of the vegetable fibers.
The vegetable fibers which are useful in the present invention include all the fibers obtained from plants as starting materials, and are exemplified by seed fibers (e.g. cotton, kapok, bombax cotton, silk cotton, vegetable silk, etc.), bast fibers (e.g. flax, hemp, jute, ramie, kenaf, sunn kemp, etc.), leaf fibers (e.g. Manila hemp, New Zealand flax, sisal hemp, pita fibers, etc.), fibers from fruits (e.g. coconuts, etc.), and others (e.g. rush, straws, fibers from seaweed algae, nettle, etc.) as well as regenerated artificial fibers based on cellulose such as viscose and cuprammonium rayons and semi-synthetic fibers based on cellulose such as acetate fibers and acetylated staple fibers. These fibers may be in the fibrous form or may be in the form of fiber structures such as woven fabrics, non-woven fabrics and felt paper.
As the ammonium salts of inorganic acids, which are useful in the present invention, are mentioned, for example, ammonium chloride, am
REFERENCES:
patent: 3847833 (1974-11-01), Bailey et al.
patent: 3969268 (1976-07-01), Fukuda et al.
patent: 4274979 (1981-06-01), Simpson
Chemical Engineering Progress-vol. 58, No. 10-10/62 pp. 42-50: "Carbon-Base Fiber Reinforced Plastics" D. L. Schmidt et al.
Hirota Hideo
Nishino Hiroshi
Suzuki Masayuki
Konopka P. E.
Takeda Chemical Industries Ltd.
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