Environmental Engineering Reference
In-Depth Information
CO 2 at 10 3.5 atm partial pressure, construct a plot showing the change
in CO 2 with pH in the closed system.
4.25 2 What is the vapor pressure of aqueous solution droplets of the follow-
ing diameters: 0.01, 0.05, 0.1, 0.5, and 1 μ m? The solution contains
1 × 10 13 g of NaCl per particle at 298 K. Plot the value of P w / P w as
a function of droplet size.
4.26 3 PSBs are ubiquitous in the environment. The average air concen-
tration in 1986 over Lake Superior for a PCB congener (2,3 ,4,4 -
tetrachlorobiphenyl) was measured as 38.7 pg/m 3 and that in surface
water was 32.1 pg/L. Obtain the magnitude and direction of air-water
exchange flux. Estimate the transfer coefficient using data in Table 4.12
and Appendix 1.
4.27 2 Phthalate esters are used as plasticizers. Di- n -butyl phthalate (DBP) is
found both in marine waters and the atmosphere. The mean concentra-
tions in the Gulf of Mexico are 94 ng/L in surface water and 0.3 ng/m 3
in air. Estimate the direction and magnitude of the annual flux of DBP.
The reported vapor pressure and aqueous solubility of DBP at 25 C are
1.4 × 10 5 mm Hg and 3.25 mg/L, respectively (Giam et al., 1978).
4.28 2 A facility operates a surface impoundment for oil field produced water
that contains benzene. The permitted annual emission is 6000 kg. The
facility operator makes sure that the impoundment is operated only during
those atmospheric conditions of instability when there is maximum mix-
ing and dispersal of benzene. Estimate the mean aqueous concentration
of benzene allowed in the impoundment. The area of the impoundment
is 10 4 m 2 .
4.29 2 Estimate the vapor pressure of the following compounds at 25 C:
Melting Point ( C)
Compound
Chlordane
103
CCl 4
23
p , p -DDT
108
Diethyl phthalate
40.5
2-Methyl phenol
30.9
4.30 2 A sample of silica is coated with 0.1% of organic carbon. The silica has
a surface area of 20 m 2 /g. Assume that only 10% of the area is occu-
pied by organic carbon. Estimate the adsorption constant for pyrene on
modified silica. Use data from Table 4.17 for the mineral contribution to
adsorption.
4.31 2 (i) Estimate the sorption constant of the following compounds
on a soil that has an organic carbon content of 1%: pen-
tachlorobenzene, phenanthrene, endrin, 2,2 -dichlorobiphenyl, and
parathion.
(ii) Estimate the effect of (a) 10 mg/L of DOC in water and (b) 0.1%
methanol in water on the partition constant of phenanthrene on the
above soil.
 
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