Environmental Engineering Reference
In-Depth Information
4.32
2
The following data are for the adsorption of a cation dodecylpyridinium
bromide on Borden sand:
log
C
i
log
W
i
(mol/kg)
(mol/L
)
−
4.8
−
7.0
−
4.6
−
6.5
−
4.3
−
6.0
−
4.1
−
5.5
−
3.8
−
5.0
−
3.4
−
4.5
−
3.1
−
4.0
Determine which isotherm (linear or Freundlich) best fits the data.
4.33
2
Contaminated sediment from a harbor is proposed to be dredged and
stored in an open confined disposal facility (CDF). The sediment concen-
trations of Aroclor 1242 and 1254 are 687 and 446 mg/kg, respectively.
The sediment suspension in water is expected to be highest immediately
after loading the CDF. The highest suspended sediment concentration
expected using the selected dredged head is 490 mg/L. The area of the
CDF is 1.3
×
10
5
m
2
. What is the expected air emission of Aroclor
1242. Properties for Aroclor 1242 and 1254 should be obtained from the
literature.
4.34
2
On April 17, 1992, a high-volume sampler was used to obtain the follow-
ing atmospheric data in Baton Rouge, Louisiana: Average air temperature
71
◦
F, concentration of fluoranthene on particulates in air
=
0.51 ng/m
3
,
particulate concentration
=
100
μ
g/m
3
. Estimate the dry (vapor) depo-
sition rate of fluoranthene. A deposition velocity of 0.1 m/s can be
assumed.
4.35
2
The mean concentration of formaldehyde in air is 0.4 ppb, whereas that in
seawater is 40 nM. What is the direction and magnitude of flux? The parti-
tion constant for formaldehyde between seawater and air can be estimated
from -log
K
aw
=−
6.7
+
3069
/T
, where
K
aw
is in mol/L atm.
4.36
2
What is the fraction of each of the following compounds partitioned from
the atmosphere to a sugar maple leaf? Assume an ambient temperature
of 25
◦
C and a typical lipid content of 0.01 g/g. The air concentration of
each compound can be assumed to be 10 ng/m
3
: naphthalene, phenan-
threne, anthracene, and pyrene. Plot your results versus log
K
oa
and
comment.
4.37
3
Sodium azide (NaN
3
) is used as a component of air bags in automobiles
(
=
10
6
kg in 1995). When dissolved in water it gives rise to volatile hydra-
zoic acid, HN
3
. It is a weak acid and the reaction HN
3
H
+
+
N
3
has
ap
K
a
value of 4.65 at 25
◦
C. The intrinsic Henry's constant
K
aw
for the
neutral species is 0.0034 at 25
◦
C (Betterton and Robinson, 1997).
(a) What is the apparent air-water partition constant at pH 7?
(b) The enthalpy of solution is
−
31 kJ/mol. Calculate the air-water
partition constant at 4
◦
C.
(c) In a wastewater at 25
◦
C, if the azide concentration is 0.1 mM at pH
6.5, will the gas phase HN
3
exceed the threshold limit value (TLV)
of 0.1 ppmv?
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