Environmental Engineering Reference
In-Depth Information
TABLE 36.1
Surface Characterization of Different Samples
BET
(m
2
/g)
Micropore
Volume (cm
3
/g)
Mesopore
Volume (cm
3
/g)
Macropore Volume
(cm
3
/g)
Sample
ACF
1375
0.620
0.052
0.037
Metal-ACF
1260
0.466
0.231
0.021
CNF
970
0.356
0.163
0.019
Source:
B. Mekala et al.,
I&EC Res.
, 50, 13092, 2011.
TABLE 36.2
Surface Characterization Data of Adsorbents
Average
Size
BET Surface Area
(m
2
/g)
Total Pore
Volume
Mesopore Volume
(cm
3
/g)
Micropore Volume
(cm
3
/g)
Sample
PBFe
0.6 mm
0.14
0.001
0
0
PBFe-Act
0.6 mm
231
0.142
0.0102
0.128
PBFe-Act-BM
100 nm
288
0.198
0.0146
0.172
PBFe-BM-Act
100 nm
781
0.468
0.0318
0.426
Source:
A.K. Sharma et al.,
Chem. Eng. Sci
., 65, 3591, 2010.
Note:
PBFe represents the phenolic beads, PBFe-Act represents the activated beads, PBFe-Act-BM represents
nanoparticles prepared by irst carbonization/activation then ball milling, and PBFe-BM-Act represents
the nanoparticles prepared by ball milling irst and then activation.
showed less BET area than the ACF samples. In principle, the nanoibers must have a large
surface area because the N
2
used as the probe molecule for the BET measurement is unable
to penetrate the nanopores of nanoibers. It has been suggested that CO
2
should be used to
measure the surface area of nanopores [44].
Table 36.2 summarizes the BET surface area, total pore volume, and PSD of the carbon-
based micro-/nanoadsorbents. The data show that the porosity of the material depends on
the sequence of activation and milling of the polymeric beads. Milling before activation
is found to be more effective at creating a large BET area than activation followed by the
milling of the beads. The BET area of the nanoparticles was ~780 m
2
/g in the former route
to synthesis, more than double of that (~300 m
2
/g) obtained in the latter route. The pore
volume was increased from ~0.1 to 0.4 cm
3
/g under the identical conditions. Table 36.2 also
describes the percentage of the volume represented by the different pore sizes (macro-,
meso-, and micro-) obtained in the samples. As shown, the pores in the activated samples
are mostly in the micropore range, contributing 90% of the total pore volume.
36.7 Nongraphitic ACF
ACF and CNF are nongraphitic and amorphous materials. Raman analysis was performed
to characterize the ACF and CNF studied herein at various stages of preparation in order
to verify that the materials are amorphous or graphitic. The laser Raman spectra of the
samples were taken using a confocal Raman instrument (Alpha model; Witec, Germany).
The data were collected using an Ar ion laser with a 514-nm wavelength as the excitation
