1. 1
EFFECT OF STIRRER RATE (RPM) ON THE FORMATION OF
TITANIUM DIOXIDE (TiO2) NANOPARTICLES VIA SOL GEL
METHOD SUPPORTED WITH CHITOSAN (Cs)
S. Sabri1a
, M.A.M. Adnan2b
1
Faculty of Engineering, Universiti Selangor (UNISEL)
45600 Bestari Jaya, Selangor Darul Ehsan, Malaysia.
Abstract—This research provide a guideline to determine the
effect of stirrer rate (RPM) on the formation of titanium dioxide
(TiO2) nanoparticles supported with chitosan (Cs) as
photocatalyst. For this research, a method that has been used
to synthesize TiO2 nanoparticles is sol-gel method. The
chemicals involved in this study is titanium isopropoxide
(TTIP), acetic acid glacial (CH3COOH), chitosan (Cs), sodium
chloride (NaCl), sodium hyrdoxide (NaOH). This method
succeeded in producing TiO2 in nanoparticles in anatase phase.
Parameter that has been controlled in this research is the stirrer
rate (RPM). There are several methods that have been
conducted to identify the size and characteristic of the TiO2 and
TiO2-Cs nanoparticles. Among the methods that have been
conducted are X-Ray Diffraction (XRD) and Field Emission
Scanning Electron Microscopy (FESEM). The sample of 1200
RPM has the smallest diameter size which is 36.157 nm and it
also has the smallest crystallite mean size which is 6.229 Å By
increasing the stirrer rate (RPM), it shows that the size of TiO2
nanoparticles become smaller and smooth but clotted in a larger
size when it combined with Cs. This research proves that the
stirrer rate plays an important role in the formation of TiO2
nanoparticles.
Key Words—Titanium dioxide, Chitosan, Photocatalyst.
1.0 INTRODUCTION
The release of untreated colored wastewaters into the
ecosystem can be very damaging to the receiving water
bodies. Untreated dyes wastewaters from dyeing industries
have a great variety of colors and not easy to biodegrade due
to its complex chemical structures [1]. This pollutant has an
adverse effect on human health and the environment and can
usually be oxidized by naturally occurring micro-organisms.
In order to provide clean water for human consumption, the
contaminants in water must be removed. It is very important
to develop process for cleaning up polluted aquifers. Their
high toxicity, even at low concentrations, has motivated the
search and improvement of many treatment techniques. An
advance oxidation process (AOP) is seemed to be the best
ways to performed environmental clean-up. AOP could be
performed by photocatalysis. This photocatalyst will produce
surface oxidation to eliminate harmful substance that presence
from textile industrial wastewater. Usually it can be employed
to destroy contamination in water or pollutants in air.
Photocatalyst, employing TiO2, is a promising
method for this purpose. TiO2 is widely used as photocatalyst
because it has the most efficient photoactivity, the highest
stability and low cost [2]. TiO2 is considered very close to a
suitable semiconductor for photocatalysis because of its high
stability and harmless toward both environment and human
[3]. In this research, nanoparticle TiO2 is prepared by a sol-gel
method. Sol gel method is a chemical synthesis method for
preparing ceramic powders and gels. The synthesis of TiO2 by
the sol gel method has proven to be useful tool for photo-
induced molecular reactions to take place on a TiO2 surface
[4]. TiO2 was added with chitosan (Cs) to improve the
efficiency of the photocatalyst. Chitosan (Cs) is a linear
randomly distributed, hetero polysaccharide consisting of β
(1-4) linked 2-acetamido-2-deoxy-β-D-glucopyranose and 2-
amino-2-deoxy-β-Dglycopyranose units [5]. A substance that
found in the exoskeleton of marine animals, is an important
additive that been used to absorb oils, greases and toxic
substances as a part of water treatment process and can
remove up to 99% turbidity [6]. The TiO2-Cs composite is
designed to meet the needs of high adsorption, self-
regeneration, easy separation, and cost-effective water
treatment.
2.0 EXPERIMENTAL
2.1 Formation of TiO2 Nanoparticles via Sol Gel Method.
The synthesis of TiO2 nanoparticles was done via sol gel
method. There are some chemicals that have been used in this
method which are titanium isopropoxide (TTIP), acetic acid
(CH₃COOH) and deionized (DI) water. During this process,
2.8mL of titanium isopropoxide is mixed together with 6mL
of acetic acid and 36mL of deionized water while magnetic
stirring was applied at the same time for 3 hours at ambient
temperature. This mixture is heated for one hour at 80oC.
After being heated for one hour, the solution was kept in an
oven at 80°C for 12 hours and amorphous TiO2 particles

2. 2
obtained. After being heated for 12 hours in the oven, the
mixture turned into yellow block crystals. These crystals
were grinded into fine white powder using a mortar and
pestle. Finally, titanium powder was stored in a furnace to
obtain the desired temperature and annealing time.
2.2 Formation of TiO2 Support with Cs Catalyst.
The experiment was started by adding 1 gram of TiO2
with 100ml of 1 v/v acetic acid. The solution is stirred for 3
hours. After the mixture was stirred, Cs solution which
contains 16 ml sodium chloride (NaCl), 120 ml of acetic acid
and 1 gram of Cs are added into the solution. Then, sodium
hydroxide (NaOH) is dropped wisely into the solution until
the pH became 10 and not more than 12. PH paper was used
to determine the pH value of the solution. Thereafter, the
solution was heated at 80o
C and stirred for 3 hours. Filter
paper was used to filter the resulting precipitate from the
solution and placed in the oven for 3 hours at 60o
C. After
being heated for 3 hours, the precipitate was pounded using a
mortar and pestle.
3.0 RESULT
3.1 Morphology Analysis on the Formation of TiO2
Figure 3.1 shows the TiO2 nanoparticles synthesized
using sol gel method was analyzed by FESEM. Four samples
of TiO2 with different stirrer rate (RPM) were tested using
this method.
Figure 3.1: SEM images of TiO2 nanoparticles with different stirrer rate
(RPM) a) 350 RPM b) 700 RPM c) 1100 RPM and d) 1200 RPM
Based on the Table 3.1, TiO2 sample that has the
highest mean diameter is sample with stirrer rate 350 RPM
which is 53.216 nm while sample at stirrer rate 1200 RPM
has the lowest mean diameter which is 36.157 nm. Based on
these data, it can be concluded that the RPM affect the size
of nanoparticles. The high speed of RPM is very important
factor for the resulted nanoparticles size because it can easily
dissolved the nanoparticles. In order to get the composition
elements, the sample was taken from disperse TiO2
nanoparticles at 1200 RPM as shown in Figure 3.2.
Table 3.1: Collected data of diameter size on TiO2 nanoparticles.
Based on the result, the sample of TiO2 with
parameter of 450°C-20°C/min have the highest mean size. In
order to get the composition elements, the sample was taken
from disperse TiO2 as shows in figure 3.2. Table 3.2 shows
the composition of the elements TiO2 for the highest mean
size.
Figure 3.2: Disperse form of TiO2 nanoparticles at 1200 RPM
Table 3.2: Composition elements of TiO2 nanoparticles at 1200 RPM.
The composition elemental analyses of the
synthesized TiO2 nanoparticles are clearly shown in Table
3.2. The results provided evidences that the required phase of
titanium (Ti) and oxygen (O) were present in the sample at
stirrer rate 1200 RPM. For weight percentage, O element has
a higher percentage compared to Ti element with 71.15%.
For atomic percentage, it shows that Ti element has higher
percentage which is 54.84% compared to O element.
3.2 Phase and Structure Investigation on the Formation of
TiO2
X-Ray Diffraction (XRD) measurement were conducted to
determine the crystal phase and crystallite size of the
synthesized nanoparticles of TiO2 with different stirrer rate
(RPM). There are four samples of TiO2 nanoparticles with
different parameter which are 350 RPM, 700 RPM, 1100
RPM and 1200 RPM were investigated. All the phases that
were investigated are successfully transformed to anatase
phase.

3. 3
Figure 3.3: XRD pattern TiO2 nanoparticles calcined at temperature of
500o
C for 1 hour with 350 RPM (stirrer rate)
Figure 3.3 exhibits the XRD pattern of TiO2
nanoparticles calcined at 500o
C for 1 hour with 350 RPM
(stirrer rate). The XRD pattern of the synthesized TiO2
exhibits Ti phase only, which indicates the nature of anatese
TiO2 with tetragonal system. The Bragg’s Law reflection of
Ti phase was detected at 2θ which are 25.48, 38.08, 48.11,
54.03, 62.86, 75.04 and 80.96 in entire XRD patterns,
corresponding to (011), (112), (020), (024), (124), (125) and
(224) crystal phase respectively. The presence of Ti phase
was identified by JCPDS-No 96-900-8214. Using the
Scherrer formula for the (hkl) peaks, the average crystallite
size was estimated to be 137.286 Åm. The result was
consistent with the SEM observation.
Figure 3.4: XRD pattern TiO2 nanoparticles calcined at temperature of 500o
C
for 1 hours with 700 RPM (stirrer rate)
Figure 3.4 exhibits the XRD pattern of TiO2
nanoparticles calcined at 500o
C for 1 hour with 700 RPM
(stirrer rate). The XRD pattern of the synthesized TiO2
exhibits Ti phase only, which indicates the nature of anatese
TiO2 with tetragonal system. The Bragg’s Law reflection of
Ti phase was detected at 2θ which are 25.35, 38.06, 48.02,
53.87, 62.62, 69.50, 75.17 and 82.75 in entire XRD patterns,
corresponding to (101), (112), (200), (105), (204), (220),
(215) and (224) crystal phase respectively. The presence of
Ti phase was identified by JCPDS-No 01-078-2486. Using
the Scherrer formula for the (hkl) peaks, the average
crystallite size was estimated to be 60.875 Åm. The result
was consistent with the SEM observation.
Figure 3.5: XRD pattern TiO2 nanoparticles calcined at temperature of
500o
C for 1 hour with 1100 RPM (stirrer rate)
Figure 3.5 exhibits the XRD pattern of TiO2
nanoparticles calcined at 500o
C for 1 hour with 1100 RPM
(stirrer rate). The XRD pattern of the synthesized TiO2
exhibits Ti phase only, which indicates the nature of anatese
TiO2 with tetragonal system. The Bragg’s Law reflection of
Ti phase was detected at 2θ which are 25.36, 38.00, 48.12,
53.88, 62.76, 69.65, 75.34 and 82.75 in entire XRD patterns,
corresponding to (101), (004), (200), (105), (204), (220),
(215) and (303) crystal phase respectively.The presence of Ti
phase was identified by JCPDS-No 01-078-2846. Using the
Scherrer formula for the (hkl) peaks, the average crystallite
size was estimated to be 63.375 Åm. The result was
consistent with the SEM observation.
Figure 3.6: XRD pattern TiO2 nanoparticles calcined at temperature of
500o
C for 1 hour with 1100 RPM (stirrer rate)
Figure 3.6 exhibits the XRD pattern of TiO2
nanoparticles calcined at 500o
C for 1 hour with 1200 RPM
(stirrer rate). The XRD pattern of the synthesized TiO2
exhibits Ti phase only, which indicates the nature of anatese
TiO2 with tetragonal system. The Bragg’s Law reflection of
Ti phase was detected at 2θ which are 27.30, 38.06, 48.15,
53.85, 62.55, 69.50, 75.40 and 82.87 in entire XRD patterns,
corresponding to (101), (112), (200), (105), (204), (301) and
(312) crystal phase respectively. The presence of Ti phase
was identified by JCPDS-No 01-071-1168. Using the
Scherrer formula for the (hkl) peaks, the average crystallite
size was estimated to be 62.286 Åm. The result was
consistent with the SEM observation.

4. 4
3.3 Morphology Analysis on the Formation of TiO2-Cs
The TiO2-Cs nanoparticles synthesized was
analyzed by FESEM. Four samples of TiO2 with different
stirrer rate (RPM) were tested using this method.
Figure 3.7: SEM images of TiO2-Cs nanoparticles with different stirrer rate
(RPM) a) 350 RPM b) 700 RPM c) 1100 RPM and d) 1200 RPM
The microstructure of the TiO2-Cs nanoparticles
with different stirrer rate was observed by FESEM in Figure
4.7. As it can be seen in the figure, the sample shows that the
TiO2-Cs formation agglomerate in large sizes when stirrer
rate at the lowest speed. Based on the condition of TiO2-Cs
catalyst at Figure 3.8, the nanoparticles at stirrer rate 1200
RPM shows reduction in the agglomeration.
Figure 3.8: SEM images of TiO2-Cs nanoparticles at stirrer rate 1200 RPM
3.4 TiO2-Cs Structure Analysis
The TiO2 nanoparticles synthesize using sol gel
method consists of small nanosize particles with a very large
specific surface area. In addition, by incorporating Cs as a
support, it inhibits the recombination of carriers and improve
photocatalytic efficiency.
For this analysis, energy-dispersive X-ray
spectroscopy (EDS) method is used for determining the
elemental composition and chemical characterization of
TiO2-Cs composite formation
Table 3.3: EDS result of TiO2-Cs Formation.
TiO2-Cs formation is a composite and has different
element and chemical properties. Based on EDS result in
Table 3.3, it shows that Ti is the major element of this TiO2-
Cs composite with 68.95% weight percentage and 40.40%
atomic percentage. It is equipped with O element with
18.85% weight percentage, 33.06% atomic percentage and
Cs element with 10.57% weight percentage and 24.69%
atomic percentage. Na and Si are smaller elements in this
composite with 0.98% and 0.65% weight percentage and
1.20% and 0.65% atomic percentage.
Figure 3.9: EDS image of TiO2-Cs
Figure 3.9: EDS image of TiO2-Cs
EDS allows to identify what those particular elements
are and their relative proportions. The elemental analyses of
the synthesized TiO2-Cs nanoparticles are clearly shown
below in Figure 3.9 and Figure 3.10. The EDS results
provided evidences that the required phase of titanium (Ti),
oxygen (O) and chitosan (C) were present in the sample of
TiO2-Cs formation.

5. 5
4.0 CONCLUSION
According to the results obtained from this research, it
showed that the sol gel method that has been used is very
suitable for the production of TiO2 in anatese phase. The
relationship between angular velocity (RPM) and size of
nanoparticles has also been proved by the parameters that
have been set during the experiment. The results show that
the size of TiO2 nanoparticles is very smooth when it is stirred
at high stirrer rate. It has been proven when the size of TiO2
nanoparticles at a speed of 1200 RPM is 36.157nm compared
to 53.216 nm at a speed of 350 RPM. For a combination of
TiO2 and Cs, the results showed a lower stirrer rate has led
TiO2-Cs clotted in a larger size than at high stirrer rate.
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