autoclave and subjected to heat at the ramp rate of 4 °C per
minute up to 250 °C. After cooling to ambient temperature,
the addition of acetone yielded a precipitate which was
isolated and dried in vacuole. XRD and TEM analysis
showed particle sizes to be small; 4 and 6 nm, respectively.
They were thus very suitable for photocatalytic applications.
2.3.3 Ultrasonic Methods
In a method using ultrasound, the precursor was titanium
isopropoxide (TIP), in a beaker, to which propanol was
added (Shirsath et al. 2013). The beaker was placed in a
controlled temperature ultrasonic bath, and sonication was
affected by placing a titanium horn in the beaker. Doping
was done using five different concentrations of cerium
nitrate added to the reaction after every 30 s after the initial
addition of sodium hydroxide as well. After additions of
solutions to the sonication beaker were completed, sonication was activated for a further 30 min. A time period was
allowed for the formed precipitate to settle in the beaker.
Thereafter, the precipitate was subjected to centrifugation,
filtering and drying and finally calcining at 450 °C for 3 h.
Undoped nano-TiO 2 was synthesized in the same way
except that the doping agent was omitted. It was found that
the catalytic activity of the nanotitanium dioxide derived via
the sonication route was higher than obtained by the conventional route.
2.4 Chemical Method
In situ synthesis of nanotitanium dioxide on a piece of cotton
fabric was performed by Sadr and Montazer (2014), who
chose titanium tetra isopropoxide (TTIP) as the source of
titanium. The other reagents were 100% glacial acetic acid,
methylene blue, non-ionic detergents and distilled water
while the fabric was bleached cotton of known waft, weave,
yarn and density. Nanotitanium dioxide was prepared on the
cloth by dispersing the TTIP on the cloth and then performing acid hydrolysis of TTIP. The sequence of steps
whole process can be outlined as follows: preparation of
aqueous acid solution in a glass beaker; immersion of
sample of fabric in the above solution; reaction beaker
placed in an ultrasonic bath and irradiated for 5 min; TTIP
added dropwise to the reaction mixture at ambient temperature. The resulting mixture was sonicated for 4 h at room
temperature and 75 °C for 2 h. The treated cloth was left in
the beaker for 24 h at room temperature; thereafter, the cloth
was washed and then dried at 70 °C for 15 min; a variety of
tests was conducted on the fabric; the salient features of ones
to note are: titanium dioxide nanoparticles were formed of
the cotton fabric; the coating of nanoparticles afforded the
fabric protection from ultraviolet (UV) ill-effects; the
nanoparticles were formed at low temperature.
2.5 Metal–Organic Chemical Vapour Deposition
(MOCVD)
In this method, titanium tetraisopropoxide (TTIP) was used
(Pradhan et al. 2003) as the precursor which was placed in a
stainless steel vessel maintained at 60 °C. Argon pressure
was used to carry the precursor to a cold wall upright
MOCVD reactor equipped with a susceptor to accommodate
the tungsten carbide–cobalt substrate. The target substrate
was cleaned by dipping in acetone, followed by ultrasonic
treatment in a deionized water bath. Each deposition
experiment was carried out for 1.5 h. The analysis revealed
that the deposited material comprised TiO 2 nanorods in
anatase phase (Pradhan et al. 2003).
3 Bioapplications of Nano-TiO 2
Manesh et al. (2018) investigated the biological aspects of
the interaction of nanotitanium dioxide with plants and
compared them with the role of nanotitanium in tandem with
CdCl 2 , a known toxin towards seedlings and plants. Radish
seeds, commercially available nanotitanium dioxide and
CdCl 2 , were the principals in this interaction study. The
nano-TiO 2 was the commercially available ones (namely
Aeroxide P25 and Degussa Evonik) and radish seeds were
from the species Raphanus sativus L. parvus. Radish seeds
were treated with a series of nano-TiO 2 solutions/
suspensions ranging from 1 to 1000 mg l
−1 . In a separate
experiment, radish seeds were subjected to solutions of
CdCl 2 at concentrations in the range from 1 to 250 mg l
−1 .
In a third set-up, radish seeds were treated with a combination of nano-TiO 2 and CdCl 2 . These experiments were
followed by toxicity tests using the Organization for Economic Cooperation and Development (OECD) 208 protocols. Calculations of percentages of seed which germinated,
germination index (GI) and root elongation were done. Other
properties that were determined were cell morphology and
oxidative stress after 5 days of treatment as described above.
Furthermore, the Z-potential of nano-TiO 2 in Milli-Q water
as exposure medium was also measured.
Dynamic light scattering experiments revealed that small
aggregates of nano-TiO 2 had formed. The results showed
that exposure to nano-TiO 2 to seeds had small effects on
percentage of germination, germination index (GI) and root
length compared to controls. By comparison, CdCl 2 caused a
marked lowering of germination % and GI for control seeds
and a concentration-dependent decrease on root length
increase were observed. In summary, the data from the
above experiments support the notion that the presence of
nano-TiO 2 does not affect the toxicity arising from the
presence of CdCl 2 . Quite importantly changes in morphology, nuclei, vacuoles and shape of radish root cells were
Interaction of Nano-TiO 2 with Plants: Preparation and Translocation
77
minute up to 250 °C. After cooling to ambient temperature,
the addition of acetone yielded a precipitate which was
isolated and dried in vacuole. XRD and TEM analysis
showed particle sizes to be small; 4 and 6 nm, respectively.
They were thus very suitable for photocatalytic applications.
2.3.3 Ultrasonic Methods
In a method using ultrasound, the precursor was titanium
isopropoxide (TIP), in a beaker, to which propanol was
added (Shirsath et al. 2013). The beaker was placed in a
controlled temperature ultrasonic bath, and sonication was
affected by placing a titanium horn in the beaker. Doping
was done using five different concentrations of cerium
nitrate added to the reaction after every 30 s after the initial
addition of sodium hydroxide as well. After additions of
solutions to the sonication beaker were completed, sonication was activated for a further 30 min. A time period was
allowed for the formed precipitate to settle in the beaker.
Thereafter, the precipitate was subjected to centrifugation,
filtering and drying and finally calcining at 450 °C for 3 h.
Undoped nano-TiO 2 was synthesized in the same way
except that the doping agent was omitted. It was found that
the catalytic activity of the nanotitanium dioxide derived via
the sonication route was higher than obtained by the conventional route.
2.4 Chemical Method
In situ synthesis of nanotitanium dioxide on a piece of cotton
fabric was performed by Sadr and Montazer (2014), who
chose titanium tetra isopropoxide (TTIP) as the source of
titanium. The other reagents were 100% glacial acetic acid,
methylene blue, non-ionic detergents and distilled water
while the fabric was bleached cotton of known waft, weave,
yarn and density. Nanotitanium dioxide was prepared on the
cloth by dispersing the TTIP on the cloth and then performing acid hydrolysis of TTIP. The sequence of steps
whole process can be outlined as follows: preparation of
aqueous acid solution in a glass beaker; immersion of
sample of fabric in the above solution; reaction beaker
placed in an ultrasonic bath and irradiated for 5 min; TTIP
added dropwise to the reaction mixture at ambient temperature. The resulting mixture was sonicated for 4 h at room
temperature and 75 °C for 2 h. The treated cloth was left in
the beaker for 24 h at room temperature; thereafter, the cloth
was washed and then dried at 70 °C for 15 min; a variety of
tests was conducted on the fabric; the salient features of ones
to note are: titanium dioxide nanoparticles were formed of
the cotton fabric; the coating of nanoparticles afforded the
fabric protection from ultraviolet (UV) ill-effects; the
nanoparticles were formed at low temperature.
2.5 Metal–Organic Chemical Vapour Deposition
(MOCVD)
In this method, titanium tetraisopropoxide (TTIP) was used
(Pradhan et al. 2003) as the precursor which was placed in a
stainless steel vessel maintained at 60 °C. Argon pressure
was used to carry the precursor to a cold wall upright
MOCVD reactor equipped with a susceptor to accommodate
the tungsten carbide–cobalt substrate. The target substrate
was cleaned by dipping in acetone, followed by ultrasonic
treatment in a deionized water bath. Each deposition
experiment was carried out for 1.5 h. The analysis revealed
that the deposited material comprised TiO 2 nanorods in
anatase phase (Pradhan et al. 2003).
3 Bioapplications of Nano-TiO 2
Manesh et al. (2018) investigated the biological aspects of
the interaction of nanotitanium dioxide with plants and
compared them with the role of nanotitanium in tandem with
CdCl 2 , a known toxin towards seedlings and plants. Radish
seeds, commercially available nanotitanium dioxide and
CdCl 2 , were the principals in this interaction study. The
nano-TiO 2 was the commercially available ones (namely
Aeroxide P25 and Degussa Evonik) and radish seeds were
from the species Raphanus sativus L. parvus. Radish seeds
were treated with a series of nano-TiO 2 solutions/
suspensions ranging from 1 to 1000 mg l
−1 . In a separate
experiment, radish seeds were subjected to solutions of
CdCl 2 at concentrations in the range from 1 to 250 mg l
−1 .
In a third set-up, radish seeds were treated with a combination of nano-TiO 2 and CdCl 2 . These experiments were
followed by toxicity tests using the Organization for Economic Cooperation and Development (OECD) 208 protocols. Calculations of percentages of seed which germinated,
germination index (GI) and root elongation were done. Other
properties that were determined were cell morphology and
oxidative stress after 5 days of treatment as described above.
Furthermore, the Z-potential of nano-TiO 2 in Milli-Q water
as exposure medium was also measured.
Dynamic light scattering experiments revealed that small
aggregates of nano-TiO 2 had formed. The results showed
that exposure to nano-TiO 2 to seeds had small effects on
percentage of germination, germination index (GI) and root
length compared to controls. By comparison, CdCl 2 caused a
marked lowering of germination % and GI for control seeds
and a concentration-dependent decrease on root length
increase were observed. In summary, the data from the
above experiments support the notion that the presence of
nano-TiO 2 does not affect the toxicity arising from the
presence of CdCl 2 . Quite importantly changes in morphology, nuclei, vacuoles and shape of radish root cells were
Interaction of Nano-TiO 2 with Plants: Preparation and Translocation
77