Activated carbon fiber

Activated carbon fibers have high surface areas, with BET surface areas ranging from around 1000 m /g to well over 2000 m /g. Beside their fibrous form, they have the following unique properties (compared with GAC and PAC)  

As a result of these unique properties, there are many advantages for using them as sorbents. Despite these properties, their present application is limited by its high cost. The total annnal worldwide production of carbon fibers in 1993 was 7300 tons, of which less than 2% was ACF (Mays, 1999). Five companies in Japan (Suzuki, 1994) provide the main snpply of ACFs. However, as production processes improve further and new demands arise for environmental applications, as well as consumer products applications, the use of ACF will undoubtedly increase. 

As a consequence of the four unique properties above, the adsorption properties of ACF are discussed accordingly. 

From their N2 adsorption data, Jaroniec et al. (1991) determined the pore sizes of PAN-based and cellulose-based ACFs, and found that 85% of the pore volumes were composed of uniform miCTopoies with a diameter 10 A. In fact, the pore sizes of ACF in all reported Uteratuie are 10 A. 

There are two likely reasons for the fine pore sizes and uniformity (or narrowness) of their size distribution. First, the ACFs have essentially zero ash  

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Product Hterature on KYNOL activated carbon fibers and cloths, GUN El Chemical Industry Co., Ltd., Japan, 1987 Product Hterature on... 

It is appropriate at this stage to consider active carbons generally, before leading on to introduce active carbon fibers, which are a relatively recent development of these materials. 

Fig. 1. Venn diagram illustrating where active carbon fibers lie in the classification of carbon materials.

Essentially, the technology of active carbon fibers is a combination of the technologies for carbon fibers and active carbons summarized above. This section is an outhne of the historical development of ACT. 

Fig. 2. Number of publications on active carbon fibers between 1981 and 1997 (dotted line is best fit linear trend).

Fig. 6. Breakthrough curves for aqueous acetone (10 mg 1" in feed) flowing through exnutshell granular active carbon, GAC, and PAN-based active carbon fibers, ACF, in a continuous flow reactor (see Fig. 5) at 10 ml min" and 293 K [64]. C/Cq is the outlet concentration relative to the feed concentration. Reprinted from Ind. Eng. Chem. Res., Volume 34, Lin, S. H. and Hsu, F. M., Liquid phase adsorption of organic compounds by granular activated carbon and activated carbon fibers, pp. 2110-2116, Copyright 1995, with permission from the American Chemical Society.

Economy, J., Daley, M. and Mangun. C., Activated carbon fibers - past, present and future, ACS Preprints (Fuel Chemistry Division), 1996, 41(1), 321 325. 

Maenair, R. N. and Arons, G. N., Sorptive textile systems containing activated carbon fibers. In Carbon Adsorption Handbook, ed. P. N. Cheremisinoff and F. Ellerbusch, Ann Arbor Science, Ann Arbor, 1978, pp. 819 859. 

Lin, R. Y. and Economy, J., Preparation and properties of activated carbon fibers derived from phenolic resin precursor, Appl. Polym. Symp., 1973, 21, 143 152. 

Endo, M., Takeuchi, K., Sasuda, Y., Matsubayashi, K., Oshida, K. and Drcsselhaus, M. S., Fractal analysis on pore structure for activated carbon fibers. Electron. Commun. Jpn., Part II Electron., 1994, 77(6), 98 107. 

Economy, J., Daley, M., Hippo, E. J. and Tandon, D., Elucidating the pore structure of activated carbon fibers through direct imaging using scanning tunneling microscopy (STM), Carbon, 1995, 33(3), 344 345... 

Kieffer, J., Investigation of the transitional pore stmeture of activated carbon fibers by small-angle neutron scattering, J. Appl. Phys., 1992, 72(12), 5649 5656. 

Cazorla-Amords, D., dc Lecea, C. S. M., Alcaniz-Monge, J., Gardner, M., North, A. and Dore, J., Characterization of activated carbon fibers by small-angle x-ray scattering. Carbon, 1998, 36(3), 309 312. 

Suzuki, T. and Kaneko, K., Structural change of activated carbon fibers with desorption by in situ x-ray diffraction. Carbon, 1988, 26(5), 744 745. 

Shin, S,. Jang, J., Yoon, S. H. and Mochida, I., A study on the effect of heat treatment on functional groups of pitch-based activated carbon fiber using FTIR, Carbon, 1997,35(12), 1739 1743. 

Bohra, J. N. and Saxena, R. K., Microporosity in rayon-based carbonized and activated carbon fibers. Colloid Surf., 1991, 58(4), 375 383. 

Jaroniec, M., Gilpin, R. K., Kaneko, K. and Choma, J., Evaluation of energetic heterogeneity and microporosity of activated carbon fibers on the basis of gas adsorption isotherms, Langmuir, 1991, 7(1 1), 2719 2722. 

Cazorla-Amoros, D., Alcaniz-Mongc, J. and Linares-Solano, A., Characterization of activated carbon fibers by COj adsorption, Langmuir, 1996, 12(11), 2820 2824. 

Lin, S. H. and Chen, Y. V., Adsorption and desorption characteristics of 1,1-dichloro-1-fluoroethane by granular activated carbon and activated carbon fiber, J. Environ. Sci. Health, Part A Toxic / Hazard Subst. Environ. Eng., 1996,31(6), 1279 1292. 

Xiu, G. H., Modeling breakthrough curves in a fixed bed of activated carbon fiber - exact solution and parabolic approximation, Chem. Eng. Sci., 1996, 51(16), 4039 4041. 

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