In Situ Remediation Technologies - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 952

simple equation is often used. If n 1, a linear relation is assumed between the

amount of adsorbed contaminant and the concentration of the contaminant dissolved
in water:

=

q s = K d ∗ C l (21.2)

with:

soil-water partitioning coefficient (m 3 /kg dw )

K d =

This equation may only be applied in situations with relatively low concentra-
tions of contaminants.
For adsorption of contaminants, the soil organic matter often plays a dominant
role, therefore K d is often substituted by K om in the literature:

K d = f om ∗ K om (21.3)

with:

organic matter-water partitioning coefficient (m 3 /kg om ), K om =

f om = fraction organic matter in soil (kg om /kg dw ).

In the literature, several relations for the value of K om can be found. Relations
of K om and the octanol-water partitioning coefficient ( K ow ) or solubility ( S ) can be
found as follows:

log K om = a ∗ log K ow + b (21.4)

log K om =

∗ +

c log S d (21.5)

with:

K ow = octanol-water partitioning coefficient (-),

solubility (mol/m 3 ). S =

In these equations different values are found for the constants a , b , c and d ,for
different contaminants.
The equilibrium relation between the dissolved phase and the vapour phase is
described by Henry's Law:

P = H ∗ C l (21.6)

with:

P = vapor pressure (Pa),

Henry coefficient (Pa m 3 /mol).

H =

This relation between the concentration in the gas phase and the concentration
in the liquid phase can also be described by the dimensionless Henry coefficient
( K H ), which is similar to the often used distribution coefficient m in Chemical
engineering: