synthesis and characterization of bismuth oxide doped titanium dioxide and its antibacterial activity

16 Pages·2017·0.43 MB·English

International Journal of Pure and Applied Mathematics
Volume 119 No. 12 2018, 6345-6359
ISSN:1314-3395(on-lineversion)
url:http://www.ijpam.eu
SpecialIssue
ijpam.eu
SYNTHESIS AND CHARACTERIZATION OF BISMUTH OXIDE DOPED TITANIUM
DIOXIDE AND ITS ANTIBACTERIAL ACTIVITY
MAGESAN.P1, SVIARANJANI.A2,
1,2Associate Professor, Department of Chemistry,
BIST, BIHER, Bharath University,Chennai-73
[email protected]

Abstract
Bi O -TiO nanocomposites were successfully synthesized by Sol-Gel method using
2 3 2
CTAB as templating agent. The synthesized materials were characterized by X-Ray Diffraction
(XRD), Energy Dispersive X-ray (EDX) spectra, Scanning Electron Microscopy (SEM), Diffuse
Reflectance Spectroscopy (DRS), Fourier Transform Infra-Red spectroscopy (FT-IR) and FT-
Raman Spectroscopy (FT-Raman). Visible light photocatalytic activity of the samples was
investigated by using Methyl orange dye. Furthermore, the antibacterial activity of the
nanocomposites was tested against gram negative bacteria (Escherichia coli).
Keywords: Composites, Sol-gel method, Semiconductivity, Antibacterial activity,
spectroscopical studies.

1. Introduction
In recent years, semiconductor photocatalysts have gained significant attention in the
degradation of environmental contaminants[1-5]. Various semiconductor photocatalysts such as
TiO [6], ZnO[7] and CdS [8] has been used for the environmental remediation process. Among the
2
various oxides semiconductor photocatalysts[6-11], TiO has been proven to be the most suitable
2
material due to its powerful oxidation strength, low cost, non-toxicity and chemical stability
against photo corrosion and chemical corrosion[9-11]. In spite of the search for the idyllic
6345
International Journal of Pure and Applied Mathematics Special Issue
photocatalyst for more than a couple of decades, titania (TiO ) in its anatase form, has persisted
2
as a touchstone photocatalyst against the activity of any emerging material is evaluated[12-21]:
Typically, the conventional TiO photocatalyst would predictably meet an obstacle when applied
2
in practical applications such as effective utilization of UV/solar light, large surface area
requirement for the adsorption of pollutant, that is, adverse recombination of electron and
holes[22-29]. Efforts have been made to extend the adsorption of light from UV to visible region
and to improve the photocatalytic efficiency of TiO [30-36]. Dopants like transition metals (Fe,
2
Al, Ni, Cr, Co, W, V and Zr) and metal oxides (Fe O , Cr O , CoO , SiO , etc.,) being used to
2 3 2 3 2 2
improve its applicability[13-15]. Reviews of Zeleska [16] has been discussed the method of
preparation of doped TiO with metallic and non-metallic species; as well as different types of
2
dopants and doping materials. Doping of visible light active material on TiO nanopowders may
2
shift the absorption threshold of TiO from UV to visible region and the photocatalytic
2
efficiencies can be higher than the pure TiO and Degussa P25[17-20]. And also doping or
2
deposition of nobel metals on titania influence the photocatalytic activity by extending the
excitation wavelength from ultraviolent region to visible region[37-42] Sol-gel synthesized
SnO -TiO composite nanoparticles show larger photocatalytic activity to degrade rhodamine B
2 2
than TiO [29]. This is due to the extended optical response, improved charge separation, etc. Also,
2
the sol-gel synthesized SnO -TiO composite films exhibit higher surface hydroxyl group density
2 2
and photocatalytic activity than pure TiO under solar irradiation[30]. The photocatalytic
2
degradation of methylene blue by Sn-doped anatase TiO nanobelts, synthesized by a two-step
2
hydrothermal treatment, increases with Sn-content under visible-light illumination[31]. Sn-doped
TiO or SnO -TiO composites have been obtained by sol-gel[32-34] or solvothermal[35] or
2 2 2
metalorganic decomposition[36] methods[43-45].
6346
International Journal of Pure and Applied Mathematics Special Issue
In this work, we have synthesized 4 % Bi O -TiO by simple precipitation method and their
2 3 2
spectroscopical studies were carried out. Methyl orange dye was used as a pollutant to determine
the photocatalytic degradation of the prepared catalysts under solar light. Furthermore, the
antibacterial activities of the nanocomposites were tested against gram negative bacteria
(Escherichia coli) under dark condition.
2. Materials and methods
2.1. Materials
Titanium Tetra IsoPropoxide (TTIP were purchased from Spectrochem, Tin Oxide (Bi O )
2 3
from SRL, Methyl orange from S.D. Fine Chemicals and Isopropyl alcohol (IPA) from RFCl
(RANKEM) were purchased and used as received. Freshly prepared de-ionized water was used in
all the experiments.

2.2. Photocatalysts synthesis
To synthesize TiO , Bi O -TiO nanoparticles, a sonochemical method was
2 2 3 2
applied. The approach for sonochemical synthesis of the above said nanocomposites was as
follows: TTIP was dissolved in isopropyl alcohol at a volume ratio of 3:10, followed by the
addition of an appropriate amount of metal oxide (Bi O ). The solution was sonicated for 1 hr in
2 3
bath type sonicator (EQUITRON) with frequency and a heating arrangement for the
sonochemical synthesis of Bi O -TiO nanoparticles. The alkoxide solution after ultrasonic
2 3 2
mixing was added drop wise to 200 ml of 0.3 M Nitric acid aqueous solution in an ice/water bath
under vigorous stirring to form a transparent homogeneous solution. Ammonia solution (0.3M)
6347
International Journal of Pure and Applied Mathematics Special Issue
was added drop wise until the pH of the solution reached around 9. After aging for 12 hrs, the
resulting white gel thus formed was separated by centrifugation and washed thoroughly by water
followed by ethanol to remove the impurities. Finally, it was dried in an oven at 80 °C for 6 hr,
followed by sintering at 500 °C for 3 hr.
Instrumentation and Analysis
The following physiochemical techniques have been used to characterize the
prepared catalysts. To characterize the phase structure of the Bi O -TiO nanoparticles; a Bruker
2 3 2
D2 Phaser Desktop X-ray Diffractometer equipped with Ni-filtered Cu Kα radiation (λ=1.542 Å)
and operated at an accelerating voltage and emission current of 30 kV and 10 mA, respectively.
Data were acquired over the range of 2θ from 0° to 70 °C with a step size of 0.0017 and a scan
rate of 7°/min. Scanning Electron Microscopy (SEM) was performed to examine the surface
morphology of the prepared nanocomposites using DXS-10 ACKT scanning electron microscope
equipped with EXS, which was used to study the elemental composition. Besides, the obtained
SEM images were analyzed using manual microstructure distance measurement software to
determine the diameter size distribution of the nanomaterials. Diffuse reflectance spectroscopy
(DRS) spectra of the samples were recorded using Shimadzu 2100 UV-Visible
spectrophotometer in the range of 200-800 nm equipped with an integrating sphere and BaSO
4
was used as the reference. For Fourier transform infrared spectroscopy (FT-IR) analysis, the KBr
pellets were prepared from Bi O -TiO powders. FT-IR analysis was performed using a
2 3 2
spectrophotometer (Perkin Elmer RX1 instrument). Fourier transform Raman spectroscopy (FT-
RAMAN) spectra of the prepared nanocomposites were recorded by using BRUKER RFS 27
spectrometer. Thermogravimetric-differential thermal analysis (TG-DTA) of the nanocomposites
was taken on WATERS SDT Q 600 TA model instrument.
6348
International Journal of Pure and Applied Mathematics Special Issue

Determination of Antimicrobial activity
The antibacterial action of the prepared nanocomposites was examined using gram
negative bacteria (Escherichia coli ATCC 25922) by well diffusion method. The prepared
Nutrient agar was poured in the sterile Petri dishes and allowed to solidify. 24 h growing
bacterial cultures (E. coli) were swabbed on it. The 5 wells (10 mm diameter) were made by
using cork borer. The four different concentrations (250 µg, 500 µg, 750 µg and 1000 µg) of the
nanoparticle, one negative control (tetracycline) were loaded in the wells. The plates were then
incubated at 37 ºC for 24 hour. After incubation, the inhibition diameter was measured and the
percentage of inhibition was calculated by using the formula (Eq. 1)
I (Diameter of the Inhibited Zone)
% of inhibition= -------------------------------------------- X100 (1)
90 (Diameter of the Petri-plate in mm)

3. Results and Discussion
3.1. XRD analysis of Bi O -TiO nanocomposites
2 3 2

XRD pattern of the prepared nanocomposites are given in the Fig.1.
In all the synthesized nanocomposites, TiO exists in anatase phase show their sharp
2
characteristic peaks at 2θ= 24.8°, 37.3°, 47.3°, 53.4°, 54.3°, 62.2° and 68.5° corresponds to the
(101), (004), (200), (105), (211), (204), (116), (220) and (215) planes agree well to standard
JCPDS card No. 89-4921 and hence confirms that the nanocomposite have been predominantly
6349
International Journal of Pure and Applied Mathematics Special Issue
crystalline in nature with anatase phase. The XRD patterns for Bi O -TiO show the peaks at
2 3 2
2θ=37.8°, 2θ=29.7° corresponding to Bi O (78-1793). The average crystallite sizes of the
2 3
nanocomposites have been deduced from the half-width of the full maximum (HWFM) of the
101anatase peak of TiO using Scherrer equation (Eq. 2),
2
t = K/cos, (2)
Where t is the crystallite size, K is the shape factor of value 0.9,  is the wavelength of
the X-ray used.  is the Bragg’s diffraction angle,  is the corrected line broadening,  =  - ,
b s
 is the broadened profile width of the experimental sample and  is the standard profile width
b s
of the reference (high purity silica) sample. According to the Eq. 2, the average crystallite sizes
of the doped TiO nanocomposite are listed in the table 1
2

3.2. FT-IR analysis
6350
International Journal of Pure and Applied Mathematics Special Issue
The FT-IR spectra of the undoped and doped TiO nanoparticles prepared by
2
sonochemical method are shown in the Fig.2. The results of FTIR analysis show four main
absorption peaks located at 650-800, 1600-1700, 2360-2400 and 3450-3500 cm-1. The presence
of strong transmittance band at 3400 cm-1 is attributed to the stretching vibrations of the O-H
groups. A weak band at around 2300 cm-1 may be attributed to the vibrations of atmospheric CO
2
and the band appearing at 1630 cm-1 can be assigned to the angular deformation of water δH-OH.
The appearance of band between 650 and 800 cm-1 are due to different vibrational modes of
TiO . In addition to this rutile and anatase TiO phase absorption bands appear in the regions of
2 2
800-650 cm-1and 850-650 cm-1, respectively. Similar results have been matching with those
reported in the literature.

Scanning Electron Microscopy
6351
International Journal of Pure and Applied Mathematics Special Issue
Fig. 5 shows the surface morphologies of the Bi O -TiO nanocomposites. As can be seen in
2 3 2
Fig. 5, the synthesized nanocomposites have non-uniform size, which may be a result of the
aggregation of the doped TiO nanocomposites with spherical shape and the growth of irregular
2
crystalline grains during synthesis. According to the SEM images and using Manual
Microstructure Distance Measurement software, the mean particle size of the doped TiO
2
nanocomposites were found and listed in the table 1. As can be seen, the diameter distribution of
most of the particles in the range of 30-60 nm.

Energy dispersive spectroscopy
The composition is very sensitive for the application; therefore the elements present in
the nanomaterials were scanned by EDS. The energy dispersive spectra of the prepared
nanocomposites were recorded in the binding region of 0-10 keV which is shown in the Fig. 6.
The signals and the atomic percentages from the spectrum reveal the presence of Ti, O, Bi, in the
6352
International Journal of Pure and Applied Mathematics Special Issue
prepared nanocomposites. Though the peaks of Bi are insignificant in the Bi O -TiO
2 3 2
nanocomposites owing to its content in TiO matrix, the atomic percentages indicate the Bi
2
particles present in the nanocomposite. There is no trace of any other impurities could be seen
within the detection limit of energy dispersive spectrum.

(b)

FT-Raman Spectroscopy
Raman spectroscopy is a technique which is flexible and availed for studying the
different phases of matter. Raman scattering spectra of Bi O -TiO nanocomposites were
2 3 2
recognized and displayed in the Fig.7.
The frequencies of the raman bands observed for anatase TiO (in the powder doped with
2
Bi O ,) is at 140-150, 390-400, 510-530, 620-650 cm-1 are shown in the Fig.7. According to( bth) e
2 3
reported literature raman bands for anatase TiO are at 146, 198, 320, 398-448, 515, 640 and 796
2
cm-1[65]. As noted above, the band at about 146 cm-1 is the strongest of all the observed bands.
Group theory depicts six raman active modes for the tetragonal anatase phase: three E modes
g
centered around145, 197 and 639 cm-1; two B modes at 399 and 519 cm-1; and one A mode at
1g 1g
513 cm-1[66]. From these results the bands at 198 cm-1 and 640 cm-1 are attributed to the E modes
g
and the one band at 400 cm-1 to the B modes and a doublet band at 520 cm-1 is assigned to A
1g 1g
and B modes. These observances are comparable with the reported literature
1g
6353
International Journal of Pure and Applied Mathematics Special Issue

Antimicrobial activity
The antibacterial activity of the Bi O -TiO and TiO nanocomposites was investigated
2 3 2 2
by adopting well diffusion method against E. coli bacterial strains under dark condition. The
zone of inhibition of the synthesized nanocomposites against E. coli is represented in the table 2.
From the results of zone of inhibition method, it is observed that the Bi O -TiO shows
2 3 2
significant inhibition around the films (Fig.10). TiO nanocomposites under dark condition.
2

6354