Agriculture Reference
In-Depth Information
2000
Houston
Arapahoe
1600
1200
Sharkey
800
400
Cd isotherms
0
0
6
12
18
Cd in Solution (mg/L)
1600
Morey
1400
Olney
1200
1000
Crowley
800
600
400
200
Cd isotherms
0
Cd in Solution (mg/L)
FIGURE 1.10
Cadmium isotherms for several soils after one day of reaction. Solid and dashed curves are
simulations using the Freundlich model.
In a heterogeneous system, sorption by the highest energy sites takes place
preferentially at the lowest solution concentrations, and as the sorbed con-
centration increases, successively lower energy sites become occupied. This
leads to a concentration-dependent sorption equilibrium behavior, that is, a
nonlinear isotherm.
Nickel isotherms for all soils are shown in FiguresĀ  1.14 and 1.15. These
results indicate similar affinities for nickel by all 10 soils when compared to
zinc. Houston soil exhibited the highest sorption, whereas most loamy soils
indicated moderate sorption affinities. Among all soils, Candor sand soils
exhibited the lowest affinity for nickel. Parameter values for K d of the linear
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