Environmental Engineering Reference
In-Depth Information
Plot the isotherm data as log
W
i
versus
C
i
w
to fit a Freundlich isotherm (Figure 4.13).
The values of
K
F
and
n
are 245 and 0.44, respectively (correlation coefficient
is 0.989).
(i) Using the Freundlich isotherm determine the adsorption capacity of the carbon
for the required effluent concentration, that is, 27
μ
g/L. This gives
w
i
=
245
(0.027)
0.44
=
50 mg HxBD/g carbon. Notice that fortuitously this is one of the
experimental points in the batch shaker flask experiments. Thus for every 0.05 g of
HxBD removed, we will need 1 g carbon.
(ii) Amount of HxBD to be removed in one day of operation is
(
1
−
0.027
)
mg/L (200) gal/min (3.785) L/gal (1.44
10
3
)
min/day (2.2.5
10
−
3
)
lb/g
×
×
(0.001) g/mg
=
2.34 lb/day. Hence mass of carbon required per day is 2.34
/
0.05
=
47 lb/day.
(iii) The total volume of carbon required is 47
/
20
=
2.3 ft
3
/day.
PROBLEMS
4.1
2
Estimate the Henry's constants for the following compounds using (i)
the bond contribution method of Hine and Mookerjee and (ii) the
group contribution scheme of Meylan and Howard:ammonia, toluene,
1,2,4-trichlorobenzene, benzyl alcohol, pentachlorophenol, and 1,1,1-
trichloroethane.
log
K
aw
Bond
(Hine and Mookerjee)
C
−
H
−
0.11
C
−
Cl
0.30
C
ar
−
H
−
0.21
C
ar
−
Cl
−
0.11
C
t
−
Cl
0.64
C
t
−
H
0.00
O
−
H
3.21
N
−
H
1.34
C
ar
−
C
ar
0.33
C
−
O
1.00
C
−
C
0.04
Note that C
ar
denotes an aromatic carbon and C
t
denotes a tertiary
C atom.
4.2
3
Thegas-phaseconcentrationofhydrogenperoxideanditsHenry'sconstant
are of critical significance in obtaining its concentration in cloud droplets.
H
2
O
2
is an abundant oxidant in the atmosphere capable of oxidizing
S(IV) in atmospheric water and is thought to be the dominant mecha-
nism of converting SO
2
from the atmosphere into a stable condensed
phase. H
2
O
2
has been observed in rainwater even in remote maritime
regions.
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