6.5 Sono–Photo-Fenton–Ferrioxalate System
In this process, the ferrioxalate complex ([Fe(C 2 O 4 ) 3 ]
3À
) is prepared by adding iron
species with oxalate salts. This complex is highly photochemically active at or near
ultraviolet range (Arslan et al. 2000; Jeong and Yoon 2005; Katsumata et al. 2010;
Monteagudo et al. 2013) and capable of absorbing the photons of the solar spectrum
up to the wavelength range of 450 nm (Monteagudo et al. 2008). During the
photoexcitation, the [Fe(C 2 O 4 ) 3 ]
3À complex undergoes a series of photochemical
reactions as per the ligand-to-metal charge transfer (LMCT) reaction mechanism
(Jeong and Yoon 2004; Zhou et al. 2004; Vedrenne et al. 2012) and produces
•
OH,
HO
•
2 , and O
• À
2 through the following reaction mechanism:
Fe C 2 O 4
ð
Þ 3
Â
à 3À þ hv ! Fe
2þ
þ 2 C 2 O
2À
4 þ C 2 O
• À
4
Fig. 6.3 Scavenging effect of
•
OH radicals by the externally added excess H 2 O 2 during the Fenton
reaction. (Reprinted with permission from Chakma 2015)
202
S. Chakma et al.
In this process, the ferrioxalate complex ([Fe(C 2 O 4 ) 3 ]
3À
) is prepared by adding iron
species with oxalate salts. This complex is highly photochemically active at or near
ultraviolet range (Arslan et al. 2000; Jeong and Yoon 2005; Katsumata et al. 2010;
Monteagudo et al. 2013) and capable of absorbing the photons of the solar spectrum
up to the wavelength range of 450 nm (Monteagudo et al. 2008). During the
photoexcitation, the [Fe(C 2 O 4 ) 3 ]
3À complex undergoes a series of photochemical
reactions as per the ligand-to-metal charge transfer (LMCT) reaction mechanism
(Jeong and Yoon 2004; Zhou et al. 2004; Vedrenne et al. 2012) and produces
•
OH,
HO
•
2 , and O
• À
2 through the following reaction mechanism:
Fe C 2 O 4
ð
Þ 3
Â
à 3À þ hv ! Fe
2þ
þ 2 C 2 O
2À
4 þ C 2 O
• À
4
Fig. 6.3 Scavenging effect of
•
OH radicals by the externally added excess H 2 O 2 during the Fenton
reaction. (Reprinted with permission from Chakma 2015)
202
S. Chakma et al.