The advanced Fenton process can also be improved by US. Solid particles
provide additional nuclei for the cavitation phenomena, increasing the number of
cavitation events in the reactor and hence the overall degradation extent (Bagal and
Gogate 2014).
7.2.12 Ferrate
Ferrates are oxo-compounds of high-valent iron species (Fe
VI
O 4
2– , Fe(V)O 4
3– , Fe
(V), and Fe(IV)O 4
4– ). FeO 4
2– is a powerful oxidizing agent both in acidic and basic
solutions.
FeO 4
2À
þ 8H
þ
þ 3e À ! Fe
3þ
þ 4H 2 O E
0
¼ þ2:20 V
ð7:88Þ
FeO 4
2À
þ 4H 2 O þ 3e À ! FeðOHÞ 3 þ 5OH À E
0
¼ þ0:72 V
ð7:89Þ
The redox potential of ferrate(VI) ions in acidic conditions is higher than that of
other oxidants/disinfectants (e.g., higher than that of ozone, Table 7.1). In aqueous
solutions, ferrate(VI) exhibits a distinctive red-violet color.
Fe
VI O 4
2– has aroused considerable interest as an environmentally friendly oxidant and disinfectant in remediation processes (Sharma et al. 1999, 2015; Sharma
2002; Jiang and Lloyd 2002; Jiang 2014; Rai et al. 2018). Interestingly, Fe
(VI) species exhibit coagulant properties with simultaneous oxidizing power, and
these dual properties (coagulation and oxidation/disinfection) are superior for
treating pollutants when compared with conventional coagulants (i.e., ferric sulfate
and aluminum sulfate), producing also small volumes of sludge. It has been significantly used as a green oxidant in synthetic organic transformations, water oxidation
catalysis, waste remediation, high-capacity battery cathodes, destruction of microorganisms, organic and inorganic contaminants, elimination of suspended/colloidal
Fig. 7.3 Simplified scheme
of heterogeneous Fenton
reactions with ZVI
7 Introduction to Oxidative Technologies for Water Treatment
143
provide additional nuclei for the cavitation phenomena, increasing the number of
cavitation events in the reactor and hence the overall degradation extent (Bagal and
Gogate 2014).
7.2.12 Ferrate
Ferrates are oxo-compounds of high-valent iron species (Fe
VI
O 4
2– , Fe(V)O 4
3– , Fe
(V), and Fe(IV)O 4
4– ). FeO 4
2– is a powerful oxidizing agent both in acidic and basic
solutions.
FeO 4
2À
þ 8H
þ
þ 3e À ! Fe
3þ
þ 4H 2 O E
0
¼ þ2:20 V
ð7:88Þ
FeO 4
2À
þ 4H 2 O þ 3e À ! FeðOHÞ 3 þ 5OH À E
0
¼ þ0:72 V
ð7:89Þ
The redox potential of ferrate(VI) ions in acidic conditions is higher than that of
other oxidants/disinfectants (e.g., higher than that of ozone, Table 7.1). In aqueous
solutions, ferrate(VI) exhibits a distinctive red-violet color.
Fe
VI O 4
2– has aroused considerable interest as an environmentally friendly oxidant and disinfectant in remediation processes (Sharma et al. 1999, 2015; Sharma
2002; Jiang and Lloyd 2002; Jiang 2014; Rai et al. 2018). Interestingly, Fe
(VI) species exhibit coagulant properties with simultaneous oxidizing power, and
these dual properties (coagulation and oxidation/disinfection) are superior for
treating pollutants when compared with conventional coagulants (i.e., ferric sulfate
and aluminum sulfate), producing also small volumes of sludge. It has been significantly used as a green oxidant in synthetic organic transformations, water oxidation
catalysis, waste remediation, high-capacity battery cathodes, destruction of microorganisms, organic and inorganic contaminants, elimination of suspended/colloidal
Fig. 7.3 Simplified scheme
of heterogeneous Fenton
reactions with ZVI
7 Introduction to Oxidative Technologies for Water Treatment
143