Biomedical Engineering Reference
In-Depth Information
oscillation in the linear concentration dependence corresponding
to the Henry isotherm but without an explicit tendency toward the
Langmuir saturation. For the graphite samples at both temperatures,
there is a section in the isotherm close to the linear section of the
Henry-Langmuir isotherm.
The adsorbate concentration in the single-wall nanotube samples
studied in at 295 K and 10
7
kPa reaches about 0.93 wt%, with (H
/C)
2
s
th
−2
exp
≈ 5.6 × 10
and (H
/C
) ≈ (H
/C) (
S
/
S
) ≈ 0.29 (Eq. (2.33)).
exp
2
2
tot
Figure 2.15
Isotherms of hydrogen sorption at 295 K (a) and 77 (b) by
single-wall nanotube samples (
) and initial graphite (
)
[72].
In graphite samples, the concentration amounts to about
0.08 wt%, with (H
s
−3
) ≈ 0.21, within
experimental error. The adsorbate content is proportional to the
adsorbate specific surface area
/C) ≈ 4.8 × 10
and (H
/C
2
2
exp
exp
, which agrees with the sorption
monolayer model. We note that the obtained values of the adsorbate
local concentrations (H
S
s
) in single-wall and graphite samples
are close, as order of magnitude, to the maximum (carbohydride)
values (Table 2.1).
The adsorbate concentration in the single-wall nanotube
samples studied in Ref. [72] at 77 K and 108 kPa reached about
2.37 wt%, with (H
/C
exp
2
s
) ≈ 0.76 (Eq. (2.33)), while
in the graphite samples investigated by the same researchers at
77 K and 103 kPa, the concentration amounted to about 0.17 wt%,
with (H
/C) ≈ 0.15 and (H
/C
exp
2
2
s
−2
) ≈ 0.44. Obviously, these
values of the adsorbate local concentrations (H
/C) ≈ 1.0 × 10
and (H
/C
exp
2
2
s
/C
) correspond
exp
2
to the maximum (carbohydride) values.
