Agriculture Reference
In-Depth Information
experimental data do not cover a sufficient range of solution concentra-
tion and if other conditions such as the amounts initially sorbed prevail
(Houng and Lee, 1998). In an arsenic adsorption study, Selim and Zhang
(2007) used
S
max
in the SOM based on average values as determined from
the Langmuir isotherm equation. This is a simple approach to obtain
S
max
estimated when a direct measurement of the sorption capacity is not avail-
able. Figures 6.18 to 6.21 show simulated adsorption results using the SOM
based on two model versions for three different soils. Based on visual
observations of the overall fit of the model to the experimental data, the
MRM Model
Concurrent Irreversible Reaction
Windsor Soil
100
80
60
C
o
= 100 mg/L
40
80
20
40
20
0
10
0 0
100
150
200
250 00
350 00
450 00
Time, hours
MRM Model
Consecutive Irreversible Reaction
Windsor Soil
100
80
60
C
o
= 100 mg/L
40
80
20
40
20
0
10
0 0
100
150
200
250
300 50
400 50
500
Time, hours
FIGURE 6.18
Experimental results of As(V) concentration in soil solution for Windsor soil versus time for
all values of
C
o
. Dashed curves were obtained using the multireaction model with concurrent
(top figure) and consecutive (bottom figure) irreversible reactions.
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