11.2.2 Resin
Ma et al. reported the immobilization of Fe
3+ on cationic exchange resin (Amberlite
IRA200) as a photocatalyst for the degradation of organic pollutants in aqueous
H 2 O 2 , and XPS studies revealed the presence of mixed Fe
3+ /Fe
2+ ionic states before
and after the reaction [11]. Li et al. explored the supported (Fe(bpy) 3 )
2+ complex on
cationic exchange resin as a photocatalyst for the degradation of organic pollutants
by activating with molecular oxygen under visible light irradiation and suggested the
involvement of active superoxide species (Fe(bpy) 3
3+ O 2 ) by EPR studies [12].
11.2.3 Clay Base
An efficient Fe 2 O 3 -pillared rectorite (Fe-R) clay was successfully developed as a
heterogeneous catalyst for photo-Fenton degradation of organic contaminants. X-ray
diffraction analysis and high-resolution transmission electron microscope analysis
clearly showed the existence of the Fe 2 O 3 nanoparticles in the Fe-R catalyst. The
catalytic activity of the Fe-R catalyst was evaluated by the discoloration and
chemical oxygen demand (COD) removal of an azo dye Rhodamine B (RhB,
100 mg/L) and a typical persistent organic pollutant 4-nitrophenol (4-NP, 50 mg/
L) in the presence of hydrogen peroxide (H 2 O 2 ) under visible light irradiation
(λ > 420 nm). It was found that the discoloration rate of the two contaminants was
over 99.3%, and the COD removal rate of the two contaminants was over 87.0%.
The Fe-R catalyst showed strong adsorption for the RhB in the aqueous solution.
Moreover, the Fe-R catalyst still showed good stability for the degradation of RhB
after five recycles [13].
Discoloration and mineralization of Reactive Red HE-3B were studied by using a
laponite clay-based Fe nanocomposite (Fe-Lap-RD) as a heterogeneous catalyst in
the presence of H 2 O 2 and UV light [14]. Fe-Lap-RD mainly consists of Fe 2 O 3
(maghemite) and Fe 2 Si 4 O 10 (OH) 2 (iron silicate hydroxide) which have tetragonal
and monoclinic structures, respectively, and has a high specific surface area (472 m
2 /
g) as well as a high total pore volume (0.547 cm
3 /g). It was observed that discoloration of HE-3B undergoes a much faster kinetics than mineralization of HE-3B. It
was also found that initial HE-3B concentration, H 2 O 2 concentration, UV light
wavelength and power, and Fe-Lap-RD catalyst loading are the four main factors
that can significantly influence the mineralization of HE-3B. At optimal conditions,
complete discoloration of 100 mg/L HE-3B can be achieved in 30 min and the total
organic carbon removal ratio can be attained 76% in 120 min, illustrating that FeLap-RD has a high photocatalytic activity in the photo-assisted UV light (254 nm)
and H 2 O 2 .
Iron–montmorillonite (Fe–Mt) with delaminated structures was synthesized via
the introduction of iron oxides into Na–montmorillonite [15]. Fe–Mt showed significant increases in the available iron content, surface area, and pore volume, along
262
11 Photo-Fenton Reaction
Ma et al. reported the immobilization of Fe
3+ on cationic exchange resin (Amberlite
IRA200) as a photocatalyst for the degradation of organic pollutants in aqueous
H 2 O 2 , and XPS studies revealed the presence of mixed Fe
3+ /Fe
2+ ionic states before
and after the reaction [11]. Li et al. explored the supported (Fe(bpy) 3 )
2+ complex on
cationic exchange resin as a photocatalyst for the degradation of organic pollutants
by activating with molecular oxygen under visible light irradiation and suggested the
involvement of active superoxide species (Fe(bpy) 3
3+ O 2 ) by EPR studies [12].
11.2.3 Clay Base
An efficient Fe 2 O 3 -pillared rectorite (Fe-R) clay was successfully developed as a
heterogeneous catalyst for photo-Fenton degradation of organic contaminants. X-ray
diffraction analysis and high-resolution transmission electron microscope analysis
clearly showed the existence of the Fe 2 O 3 nanoparticles in the Fe-R catalyst. The
catalytic activity of the Fe-R catalyst was evaluated by the discoloration and
chemical oxygen demand (COD) removal of an azo dye Rhodamine B (RhB,
100 mg/L) and a typical persistent organic pollutant 4-nitrophenol (4-NP, 50 mg/
L) in the presence of hydrogen peroxide (H 2 O 2 ) under visible light irradiation
(λ > 420 nm). It was found that the discoloration rate of the two contaminants was
over 99.3%, and the COD removal rate of the two contaminants was over 87.0%.
The Fe-R catalyst showed strong adsorption for the RhB in the aqueous solution.
Moreover, the Fe-R catalyst still showed good stability for the degradation of RhB
after five recycles [13].
Discoloration and mineralization of Reactive Red HE-3B were studied by using a
laponite clay-based Fe nanocomposite (Fe-Lap-RD) as a heterogeneous catalyst in
the presence of H 2 O 2 and UV light [14]. Fe-Lap-RD mainly consists of Fe 2 O 3
(maghemite) and Fe 2 Si 4 O 10 (OH) 2 (iron silicate hydroxide) which have tetragonal
and monoclinic structures, respectively, and has a high specific surface area (472 m
2 /
g) as well as a high total pore volume (0.547 cm
3 /g). It was observed that discoloration of HE-3B undergoes a much faster kinetics than mineralization of HE-3B. It
was also found that initial HE-3B concentration, H 2 O 2 concentration, UV light
wavelength and power, and Fe-Lap-RD catalyst loading are the four main factors
that can significantly influence the mineralization of HE-3B. At optimal conditions,
complete discoloration of 100 mg/L HE-3B can be achieved in 30 min and the total
organic carbon removal ratio can be attained 76% in 120 min, illustrating that FeLap-RD has a high photocatalytic activity in the photo-assisted UV light (254 nm)
and H 2 O 2 .
Iron–montmorillonite (Fe–Mt) with delaminated structures was synthesized via
the introduction of iron oxides into Na–montmorillonite [15]. Fe–Mt showed significant increases in the available iron content, surface area, and pore volume, along
262
11 Photo-Fenton Reaction