Electrolysis: processes – compositions used therein – and methods – Electrolytic material treatment
Reexamination Certificate
1999-01-13
2001-04-10
Phasge, Arun S. (Department: 1724)
Electrolysis: processes, compositions used therein, and methods
Electrolytic material treatment
C205S768000
Reexamination Certificate
active
06214201
ABSTRACT:
TABLE OF CONTENTS
1. BACKGROUND OF THE INVENTION
1.1 Field of the Invention
1.2 Description of the Prior Art
2. SUMMARY OF THE INVENTION
3. BRIEF DESCRIPTION OF THE DRAWINGS
4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
4.1 Example 1
4.2 Example 2
4.3 Example 3
4.4 Example 4
4.5 Example 5
4.6 Example 6
4.7 Example 7
4.8 Table 1
4.9 Table 2
5. CLAIMS
6. ABSTRACT
7. DRAWING
1. BACKGROUND OF THE INVENTION
1.1 Field of the Invention
The present invention relates to a process for manufacturing highly functional activated carbon fibers having oxygen functional groups introduced onto the surface thereof by anodic oxidation, the product resulting from this process and the use of this product. More specifically, it relates to a process for manufacturing activated carbon fibers having greatly improved adsorption performance time and adsorption performance when in contact with surface oxides such as in the case where gas and liquid impurities are treated by an anodic oxidation treatment of conventional activated carbon fibers by electrochemical techniques using an acidic and alkaline solution as an electrolyte.
1.2 Description of the Prior Art
As pollution of the environment has become a public concern, the removal of liquid and gas impurities has become a public demand. Under such circumstances, the development of improved adsorbents to meet such demands is urgently needed.
The activated carbon fibers have highly specific surface area and surface reactivity, good adsorptivity and micropores. They have been widely used in waste water and sewage disposal apparatus in houses and industrial facilities, apparatus for removing harmful gases in the facilities for manufacturing semiconductors and precision measuring machines, anti-gas masks for military use and general industrial use and air cleaning apparatus in offices and houses.
The activated carbon fibers have been used for the purpose of purification, collection and separation in many fields. They are organic adsorbents in a saturated binding form and have the well-developed micropores, which are the barometers for evaluating adsorptivity as adsorbents, as compared to inorganic adsorbents of an unsaturated binding form such as silica gel, alumina gel and synthetic zeolite. They also show a good molecular sieve effect, because they have a further broader adsorption surface area and a comparatively regular size of micropore as compared to conventional carbon fibers, the shape of which is restricted to a granular or powder form. In addition, they have good stability, cyclability, and processibility clue to a fiber form, thereby the demand for such carbon fibers gradually increases.
The conventional methods for improving the performance of activated carbon fibers include methods for introducing functional groups onto activated carbon fibers such as:
1) developing micropores and a specific surface area by thermally treating activated carbon fibers at high temperature,
2) forming surface functional groups by dipping activated carbon fibers in an acidic or alkaline solution, or
3) forming functional groups on activated carbon fibers by reacting activated carbon fibers in a gas at high temperature.
However, these methods have several problems. The surface structure and surface properties of the activated carbon fibers may depend on activating temperature and time, however, it is difficult to control time and temperature. Since side reactions may be caused where surface treatment is conducted in a high temperature gas, many apparatus and costs for inhibiting those side reactions are needed. In addition, since the surface functional groups attached to the surface of the activated carbon fibers are not able to continuously display their function, the adsorption performance thereof is unsatisfactory.
2. SUMMARY OF THE INVENTION
The present inventors have undertaken extensive studies in order to overcome the above-mentioned problems inherent in the aforementioned preparation of activated carbon fibers. As a result, the present inventors have now found that functional activated carbon fibers can be obtained by treating the surface of conventional activated carbon fibers through an electrochemical technique. The present invention is attained on the basis of this finding.
It is therefore an objective of the invention to provide a method for manufacturing highly functional activated carbon fibers, characterized by the following features:
a) there is no need to control time and temperature in treating activated carbon fibers, and
b) it is possible to improve and continuously display the adsorptivity without necessitating separate apparatus or processes for avoiding side reactions.
The present invention relates to a process for manufacturing highly functional activated carbon fibers, which comprises placing conventional activated carbon fibers between an anode and a cathode plate in an electrolytic solution, and applying a voltage of about 1V to about 20V at a current density of about 5 mA/m
2
to about 450 mA/m
2
between the anode and the cathode plate for an effective amount of time. The present invention also relates to the product obtained by this process, and the use of the product so obtained.
In one embodiment the product is used to treat gas and liquid impurities.
The other objectives and features of the present invention will become apparent to those skilled in the art from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.
REFERENCES:
patent: 4234398 (1980-11-01), Yamamoto
patent: 5589055 (1996-12-01), Kobayashi et al.
Kim Ki-dong
Lee Jae-Rock
Park Byung-Jae
Park Soo-Jin
Korean Research Institute of Chemical Technology
Pennie & Edmonds LLP
Phasge Arun S,.
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