Muñoz-Batista et al. (2016) studied the disinfection of E. coli 1337-H irradiated
under ultraviolet and visible light and synthesized CeO 2 –TiO 2 composite photolytic
material. These authors reported high disinfection capacity for the composite material mixed with 0.025CeTi and 0.05CeTi concentrations while increasing the concentration of CeO 2 to 25% leads to a decrease in the disinfection compared to pure
titanium oxide. This shows that the disinfection process of titanium oxide depends
upon the light irradiation as well as the ratio of the composite material. However,
titanium oxide only shows a high disinfection process, whereas CeO 2 shows no
disinfection process. Similar results are also reported in several recent studies (Aslan
et al. 2014; Hassan et al. 2016; Jeong and Guyot-Sionnest 2016; Li et al. 2016b;
Roushani et al. 2015; Shi et al. 2015; Xie et al. 2015; Zhou et al. 2011, 2012).
In general, composite nanoparticles show a higher disinfection process than bulk
photocatalytic material (Wang et al. 2017a, b, c); however, optimizing the ratio
component of the composite material is necessary to increase the activity of the
disinfection process.
7.2.2 One-Dimensional Nanostructures
After discovering carbon nanotubes in 1935, significant research efforts have been
dedicated to studying the one-dimensional nanostructures. These structures can be
obtained by combining different nanostructures such as nanoribbons, nanobelts,
nanotubes, nanowires, and nanorods. These structures present unique physical
properties and promising disinfection applications than bulk material as it was
reported (Iijima 1991; Liang et al. 2010; Liu et al. 2012a).
The main advantages of one-dimensional nanostructures are (i) their ability to
improve the process charge separation, (ii) their high surface area and pore volume,
and (iii) their high absorbance compared to bulk materials used for disinfection
(Shankar et al. 2009; Tang et al. 2011; Weng et al. 2014). Among the reported
one-dimensional nanostructures, great attention was given toward nanorods and
nanowires.
Nanorods
One-dimensional material can be prepared with TiO 2 and ZnO using various
approaches such as flame spray pyrolysis, electrodeposition, and hydrothermal
process (Hassan et al. 2012; Karunakaran et al. 2012; Sapkota et al. 2011). Bai
et al. (2013) reported on the preparation of 1 μm nanorods prepared by the calcination of TiO 2 in different superficial, no hydrothermal approaches. These authors
showed that high surface area and pore volume nanorods prepared at 400
C (TiO 2 –
400) could disinfect bacteria and degrade organic pollutants. Moreover, by increasing the preparation temperature from 400 to 900
C, these TiO 2 nanorods led to the
failure of its structure. However, they showed a high degradation capacity for
220
T. G. Ambaye et al.
under ultraviolet and visible light and synthesized CeO 2 –TiO 2 composite photolytic
material. These authors reported high disinfection capacity for the composite material mixed with 0.025CeTi and 0.05CeTi concentrations while increasing the concentration of CeO 2 to 25% leads to a decrease in the disinfection compared to pure
titanium oxide. This shows that the disinfection process of titanium oxide depends
upon the light irradiation as well as the ratio of the composite material. However,
titanium oxide only shows a high disinfection process, whereas CeO 2 shows no
disinfection process. Similar results are also reported in several recent studies (Aslan
et al. 2014; Hassan et al. 2016; Jeong and Guyot-Sionnest 2016; Li et al. 2016b;
Roushani et al. 2015; Shi et al. 2015; Xie et al. 2015; Zhou et al. 2011, 2012).
In general, composite nanoparticles show a higher disinfection process than bulk
photocatalytic material (Wang et al. 2017a, b, c); however, optimizing the ratio
component of the composite material is necessary to increase the activity of the
disinfection process.
7.2.2 One-Dimensional Nanostructures
After discovering carbon nanotubes in 1935, significant research efforts have been
dedicated to studying the one-dimensional nanostructures. These structures can be
obtained by combining different nanostructures such as nanoribbons, nanobelts,
nanotubes, nanowires, and nanorods. These structures present unique physical
properties and promising disinfection applications than bulk material as it was
reported (Iijima 1991; Liang et al. 2010; Liu et al. 2012a).
The main advantages of one-dimensional nanostructures are (i) their ability to
improve the process charge separation, (ii) their high surface area and pore volume,
and (iii) their high absorbance compared to bulk materials used for disinfection
(Shankar et al. 2009; Tang et al. 2011; Weng et al. 2014). Among the reported
one-dimensional nanostructures, great attention was given toward nanorods and
nanowires.
Nanorods
One-dimensional material can be prepared with TiO 2 and ZnO using various
approaches such as flame spray pyrolysis, electrodeposition, and hydrothermal
process (Hassan et al. 2012; Karunakaran et al. 2012; Sapkota et al. 2011). Bai
et al. (2013) reported on the preparation of 1 μm nanorods prepared by the calcination of TiO 2 in different superficial, no hydrothermal approaches. These authors
showed that high surface area and pore volume nanorods prepared at 400
C (TiO 2 –
400) could disinfect bacteria and degrade organic pollutants. Moreover, by increasing the preparation temperature from 400 to 900
C, these TiO 2 nanorods led to the
failure of its structure. However, they showed a high degradation capacity for
220
T. G. Ambaye et al.