Environmental Engineering Reference
In-Depth Information
110
Present of UV light
1.0
99.92
100
Present of UV light
FNT1
90
0.8
FNT2
FNT3
FNT4
NT
FT
TiO2
Absence of Catalysis
80
71.88
70
0.6
60
50
42.48
0.4
40
35.29
32.53
31.52
27.83
30
21.29
0.2
20
10
0.0
0
0
10
20 30 40
Irradiation Time (min)
50
60
70
80
90
FNT1 FNT2 FNT3 FNT4
NT
FT
TiO2
Ab
Cat
(
a
)
(
b
)
Catalysts (g/L)
Absence of UV light
80
1.0
Absence of UV light
FNT1
FNT2
FNT3
FNT4
NT
FT
TiO2
Absence of Catalysis
64.51
0.8
60
55.29
0.6
40.46
40
33.54
0.4
29.49
25.43
20
18.25
0.2
15.11
0.0
0
0
20
40
60
80
100
FNT1
FNT2 FNT3 FNT4
NT
FT
TiO2Ab Cat
Absence of UV light
Catalysts (g/L)
(
c
)
(
d
)
Figure 15.11 (
a-d); (d) represents the reaction rate constant and degradation ei ciency
of 4-nitrophenol, in presence and absence of UV light and catalysts.
reduced to 4-aminophenol within 10 minutes in the presence of FNT1 and
UV light, but in the absence of catalysts it takes approximate 82 minutes,
as shown in Figure 15.11. h e catalytic activity of FNT1 is much faster in
the presence of UV light compared to the absence of UV light. h erefore,
FNT1 catalysts give much faster reaction kinetics (5.89×10
-5
min
-1
) than that
of FNT2, FNT3, FNT4 and their corresponding Fe/Nb titanates and TiO
2
due to the high porosity of the materials and small particle sizes. h e FNT1
catalyst led to a signii cant decrease of the absorption peak at 415 nm and
increase of absorbance peak at 285 nm in UV-vis spectra corresponding
to 4-NP. During the reduction, the yellow color faded with the simultane-
ous formation of a slight shit ing peak position, and a new peak arose at
294 nm assigned to 4-AmP in UV-vis spectra in Figure 15.12 [133, 134].
h e complete disappearance of the UV-vis absorption peak at 415 nm of
4-NP occurred at 10 min, which meant the complete reduction of 4-NP
to 4-AmP. h is is probably due to ei cient generation of electron and hole
through mutual charge transfer from Fe(III) and Nb(V) ion in the presence
of UV light, where the electron resides in the conduction band and a hole is
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