462
S. Das et al.
and ultrasonic exfoliation was created, showed visible light-driven photocatalytic
inactivation of E. coli nearly 7-log reduction within 4 h, unlike their bulk counterparts. This enhancement of photocatalytic efficiency might be credited to the low
charge transfer resistance and slower electron–hole recombination.
2.6 Magnetically Separable Photocatalysts for Better
Reusability
Iron oxide and some minerals possess the magnetically separable properties might
be a good photocatalyst absorbing at visible spectrum of light. In contrast to universally used TiO 2 and ZnO, which mainly absorbs at UV spectrum corresponding to
just 5% of the solar spectrum due to its wide bandgap of 3.2 eV. Fe 2 O 3 on the other
hand have a bandgap of 2.2 eV (Akhavan and Azimirad 2009) and thus is an exciting
n-type semiconductor suitable for photocatalysis under visible light spectrum. This
better photocatalytic can be attributed to eventual creation of electron–hole pairs
via the narrow bandgap illumination. Many variety of Iron (III) oxides have been
anticipated like α-Fe 2 O 3 ,γ-Fe 2 O 3 , α-FeOOH, β-FeOOH, and γ-FeOOH, to degrade
organic pollutants and disinfection of bacteria (Zhong et al. 2017). Moreover, these
materials work in both liquid and gaseous phase, possess good post-reaction separability, easy to synthesize, high quantum-yield and kinetics, and efficiency, improved
surface area and surface charge transfer (Bandara et al. 1997). These iron oxide NCs
are evocative for new ways for successful manipulation of photocatalytic properties
of iron oxide toward a benign and useful substance in wastewater treatment.
Magnetic iron oxide NC scan be formulated into composites based on TiO 2 or
ZnO and other magnetic nanostructures/minerals with enhanced photocatalytic properties. Configuration is based on a magnetic core coated with a titania nanoshell
(Iron oxide Core@TiO 2 /ZnO), which has been reported. Other group includes a
magnetic core, an interlayer of mesoporous SiO 2 and titania or ZnO outer shell
(Core@Coating@TiO 2 /ZnO). Reports regarding composites with surface decoration
using various dopants (Ag/Au/N) have also been explored (Core@(Coating)@TiO 2 -
doped). Huang et al. reported the utility of Ag/AgBr@CoFe 2 O 4 composites
(250 mg/L) as good antibacterial agents against E. coli under visible light (Huang
et al. 2017). This is based on the Z-scheme pathway for photocatalytic mechanism.
In another report by Ma et al., Fe 3 O 4 –TiO 2 Nanosheets synthesized using lamellar reverse micelles and solvothermal technique was found to have photocatalytic
antibacterial effect on both E. coli and S. aureus at very less concentration (Ma
et al. 2015). The synthesized photocatalysts were found to be efficient even after five
repeated cycles. According to them, this happens as a result of H 2 O 2 generation by
the NCs, which substantially damages the bacterial membrane and deteriorates the
whole bacteria structure. The antibacterial effects of iron oxide NCs are not restricted
to photocatalysis only. Pairing radiofrequency with magnetic Fe 3 O 4 @SiO 2 –NH 2
core–shell NPs may serve as an alternative physical technique for disinfection of
S. Das et al.
and ultrasonic exfoliation was created, showed visible light-driven photocatalytic
inactivation of E. coli nearly 7-log reduction within 4 h, unlike their bulk counterparts. This enhancement of photocatalytic efficiency might be credited to the low
charge transfer resistance and slower electron–hole recombination.
2.6 Magnetically Separable Photocatalysts for Better
Reusability
Iron oxide and some minerals possess the magnetically separable properties might
be a good photocatalyst absorbing at visible spectrum of light. In contrast to universally used TiO 2 and ZnO, which mainly absorbs at UV spectrum corresponding to
just 5% of the solar spectrum due to its wide bandgap of 3.2 eV. Fe 2 O 3 on the other
hand have a bandgap of 2.2 eV (Akhavan and Azimirad 2009) and thus is an exciting
n-type semiconductor suitable for photocatalysis under visible light spectrum. This
better photocatalytic can be attributed to eventual creation of electron–hole pairs
via the narrow bandgap illumination. Many variety of Iron (III) oxides have been
anticipated like α-Fe 2 O 3 ,γ-Fe 2 O 3 , α-FeOOH, β-FeOOH, and γ-FeOOH, to degrade
organic pollutants and disinfection of bacteria (Zhong et al. 2017). Moreover, these
materials work in both liquid and gaseous phase, possess good post-reaction separability, easy to synthesize, high quantum-yield and kinetics, and efficiency, improved
surface area and surface charge transfer (Bandara et al. 1997). These iron oxide NCs
are evocative for new ways for successful manipulation of photocatalytic properties
of iron oxide toward a benign and useful substance in wastewater treatment.
Magnetic iron oxide NC scan be formulated into composites based on TiO 2 or
ZnO and other magnetic nanostructures/minerals with enhanced photocatalytic properties. Configuration is based on a magnetic core coated with a titania nanoshell
(Iron oxide Core@TiO 2 /ZnO), which has been reported. Other group includes a
magnetic core, an interlayer of mesoporous SiO 2 and titania or ZnO outer shell
(Core@Coating@TiO 2 /ZnO). Reports regarding composites with surface decoration
using various dopants (Ag/Au/N) have also been explored (Core@(Coating)@TiO 2 -
doped). Huang et al. reported the utility of Ag/AgBr@CoFe 2 O 4 composites
(250 mg/L) as good antibacterial agents against E. coli under visible light (Huang
et al. 2017). This is based on the Z-scheme pathway for photocatalytic mechanism.
In another report by Ma et al., Fe 3 O 4 –TiO 2 Nanosheets synthesized using lamellar reverse micelles and solvothermal technique was found to have photocatalytic
antibacterial effect on both E. coli and S. aureus at very less concentration (Ma
et al. 2015). The synthesized photocatalysts were found to be efficient even after five
repeated cycles. According to them, this happens as a result of H 2 O 2 generation by
the NCs, which substantially damages the bacterial membrane and deteriorates the
whole bacteria structure. The antibacterial effects of iron oxide NCs are not restricted
to photocatalysis only. Pairing radiofrequency with magnetic Fe 3 O 4 @SiO 2 –NH 2
core–shell NPs may serve as an alternative physical technique for disinfection of