Environmental Engineering Reference
In-Depth Information
Fig. 10
Relationships
between the Ln(
FI
/
FI
0
) and
the integrated solar intensity
and the integrated solar
intensity for upstream waters
(
a
and
b
Kago upstream
and Nishi-Mataya upstream,
respectively) and downstream
waters (
c
Yasu River).
Open circle
indicates the
changes in fulvic acid-like
fluorescence intensity (FI)
and
open triangle
in
c
shows
the change in the protein-
like FI under the irradiated
condition.
Data source
Mostofa et al. (
2007a
)
(a)
(b)
(c)
Integrated solar intensity (MJ m
-2
)
intensity, and
S
is the integrated solar intensity (MJ m
−
2
). Photodegradation of
FI can be clearly understood from the relationship between the
S
and Ln(
FI/FI
o
)
(Mostofa et al.
2007a
).
In river water, the reaction rate constant of fulvic acid-like FI is significantly
higher in the first step of photodegradation (8.9-20
×
10
−
3
MJ
−
1
m
2
) than in the
second step (5.6-8.5
×
10
−
3
MJ
−
1
m
2
) (Mostofa et al.
2007a
). The photodegrada-
tion rate constant of protein-like FI often follows one-step kinetics with respect to
integrated solar radiation. The photodegradation rate constant of tryptophan-like
