Page 121 - Adsorbents fundamentals and applications

106 ACTIVATED CARBON

potentials from surrounding surfaces, as discussed in Chapters 2 and 4. This
point is further discussed in 5.6.1 (Adsorption Isotherms).
(2) Small and uniform fiber diameter: The precursors of ACF are carbon
fibers. Because the fibers are made from a variety of spinning techniques (e.g.,
Edie and McHugh, 1999), they are available in remarkably uniform diameters.

3µ 1,500Å

(×3,000) (×60,000)
Figure 5.18. Scanning electron microscope images of activated carbon fibers. ‘‘Kynol’’ ACF,
activated from phenolic resin fibers by Kuraray Chemical Co., Ltd., Japan, with permission.

20
1000
1500 Cellulose-based
7
Fiber diameter (µ) 10 5 PAN-based 10 500 15 Phenol resin-based
1600
10
15
20 Pitch-based
200
25
300
20
15
25
400
(not specified)
0 600
(a)
1.4
Toluene
1.2
(Pitch-based)
Amount adsorbed of benzene or toluene (g/g) 0.8
1.0
0.6
0.4
phenol, PAN-based)
0.2
0.0 Benzene (cellulose,
(b)
◦
Figure 5.19. Fiber diameters and adsorption capacities (at 20 C) of various ACF’s (from
Suzuki, 1994, with permission). The corresponding capacities for GAC are 0.33 (benzene), 0.35
(toluene), and 0.30 g/g (phenol).