A novel nanocomposite of polyaniline and Fe0.01Ni 0.01Zn0.98O: Photocatalytic, electrical and antibacterial properties

Article abstract of DOI:10.1016/j.jallcom.2013.05.120

A novel composite of Fe_0.01Ni_0.01Zn_0.98O nanoparticles (FNZPs) and conducting polymer polyaniline (PANI) was synthesized by in situ free radical polymerisation method. Iron/nickel co-doped zinc oxide nanoparticles (NPs) were synthesized by sol-gel technique. The NPs and Fe _0.01Ni_0.01Zn_0.98O/polyaniline nanocomposites (FNZP/PANI) were characterized by FTIR, EDX, SEM, HRTEM, SAED, UV-Vis and XRD techniques. Optical and photocatalytic studies revealed that formation of composite further lowers the optical band gap of FNZPs, leading to enhanced visible light absorption. Admirable photodegradation efficiency against methylene blue dye (MB) was achieved for composites. The electrical conductivity was also enhanced. The antibacterial activity of the synthesized NPs and nanocomposites (NCs) against Escherichia coli (E coli) bacteria was analyzed by optical density method.

Full text of DOI:10.1016/j.jallcom.2013.05.120

Journal of Alloys and Compounds 578 (2013) 249–256
Contents lists available at SciVerse ScienceDirect
Journal of Alloys and Compounds
journal homepage: www.elsevier.com/locate/jalcom
A novel nanocomposite of polyaniline and Fe0.01Ni0.01Zn0.98O:
Photocatalytic, electrical and antibacterial properties
Shashi Kant a, Susheel Kalia b, Amit Kumar a,
⇑
a Department of Chemistry, Himachal Pradesh University, Summer Hill, Shimla 171 005, India
b Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, 40131 Bologna, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 12 April 2013
Received in revised form 12 May 2013
Accepted 16 May 2013
Available online 25 May 2013
A novel composite of Fe0.01Ni0.01Zn0.98O nanoparticles (FNZPs) and conducting polymer polyaniline
(PANI) was synthesized by in situ free radical polymerisation method. Iron/nickel co-doped zinc oxide
nanoparticles (NPs) were synthesized by sol–gel technique. The NPs and Fe0.01Ni0.01Zn0.98O/polyaniline
nanocomposites (FNZP/PANI) were characterized by FTIR, EDX, SEM, HRTEM, SAED, UV–Vis and XRD
techniques. Optical and photocatalytic studies revealed that formation of composite further lowers the
optical band gap of FNZPs, leading to enhanced visible light absorption. Admirable photodegradation effi-
ciency against methylene blue dye (MB) was achieved for composites. The electrical conductivity was
also enhanced. The antibacterial activity of the synthesized NPs and nanocomposites (NCs) against Esch-
erichia coli (E. coli) bacteria was analyzed by optical density method.
Keywords:
Nanocomposite
Conducting polymer
Conductivity
Photodegradation
HRTEM
Ó 2013 Elsevier B.V. All rights reserved.
Antibacterial properties
1. Introduction
good environmental stability and large variety of applications [4]
which make it suitable for gas sensor, as pH switching electrical
In the recent years, the synthesis and engineering of inorganic/
organic hybrid materials in nano-scale have received great atten-
tion due to wide range of applications. Organic–inorganic compos-
ites may combine the advantages of both components and may
offer special properties through reinforcing or modifying each
other. Polymer matrices reinforced with inorganic nanoparticles
combine the functionalities of polymer such as low weight and
ease of synthesis with unique features of inorganic nanoparticles
[1]. Research is also evolving towards materials that are designed
to perform more complex and efficient tasks. Examples include
materials that bring about a higher rate of decomposition of pollu-
tants, a selective and sensitive response toward a given bio-mole-
cule, an improved conversion of light into current or more efficient
energy storage. For such and more complex tasks to be realized,
novel materials have to be based on several components whose
spatial organization is engineered at the molecular level. Zinc oxide
is a popular semiconductor oxide with wide tunable band gap
(3.37 eV) and large exciton binding energy (60 MeV) [2]. The incor-
poration of nano-fillers into polymer matrix provides opportunities
to enhance the properties of conventional composite materials [3].
The conducting polyaniline (PANI) is one of the best known con-
ducting polymers due to its high conductivity, ease of preparation,
conducting biopolymer hybrid for sensor applications [5], as an
electrically active redox biomaterial, as a matrix for preparation
of conducting polymer NCs [6,7]. Therefore, there has been a revo-
lutionary progress in the preparation of nanocomposites based on
PANI. Polyaniline is the only conducting polymer whose electrical
properties can be controlled suitably by charge-transfer doping
and/or protonation. Inorganic–organic composite materials are
important due to their extraordinary properties, which arise from
the synergism among the properties of the components. These
materials are seeking much interest due to the remarkable change
in properties such as mechanical [8], thermal [9–11], electrical
[12], and magnetic [13] compared to pure organic polymers. Toxic
effluents from industries are a matter of serious concern for the
environment. Wide metal oxide semiconductors are attractive can-
didates for the removal of pollutants in water as they are capable of
acting as catalysts upon exposure to light radiation to degrade
harmful contaminants as dyes. The hybrid organic–inorganic
nanomaterials can prove to be better agents.
Our synthesized FNZP/PANI hybrid nanocomposite is one of its
kinds which combine the benefits of dopants (transition metal
ions) and conducting polymer along with semiconductor metal
oxide (ZnO). The Polyaniline acts as sensitizer thus enhances the
light absorption. We have utilized this product for removal of noto-
rious dye as methylene blue (MB) from aqueous medium. The
nanocomposite has exceptionally good antibacterial activity
against E. coli.
⇑
Corresponding author. Tel.: +91 177 2830944.
E-mail addresses: mittuchem83@gmail.com, drsklomesh@rediffmail.com
(A. Kumar).
0925-8388/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jallcom.2013.05.120

250
S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
3. Results and discussions
2. Materials and methods
2.1. Synthesis
3.1. Characterization
All the chemicals used in synthesis were of analytical grade. Zinc nitrate, ani-
line, ferric nitrate and nickel nitrate and citric acid were procured from MERCK In-
dia and used as received.
For the synthesis of Fe0.01Ni0.01Zn0.98O nanoparticles Zn (NO3)2 (11.652 g), Ni
(NO3)2 (0.162 g) and Fe2 (NO3)3 (0.073 g) were mixed and dissolved in 100 ml dou-
ble distilled water. Citric acid (4.66 g) was added to this suspension with constant
stirring. The pH of reaction mixture was kept 7 by adding liquid NH3 solution drop
wise. The solution was then dried at 80 °C to obtain a gel. The gel was then grinded
and sintered at 600 °C for 2 h.
The FNZP/PANI nanocomposite was prepared by in situ free radical polymerisa-
tion of aniline. 500 mg of FNZP nanoparticles was dispersed in 100 ml of water and
50 ml of 10% aniline solution (in 1 M HCl) and 50 ml of 0.1 M Ammonium persul-
phate (in 1 M HCl) were added drop wise to this. The mixture was allowed to stir
in ice bath (0–5 °C) for 3 h and then kept overnight for digestion. The sample was
then centrifuged to remove soluble impurities and side products.
3.1.1. XRD analysis
The XRD pattern of the FNZPs (Fig. 1a) reveals that there is no
change in the wurtzite structure of ZnO after Ni/Fe doping. The
XRD pattern for FNZP show broad peaks at the positions of
31.5661, 34.4417, 36.2883, 47.6271, 56.6760, 62.7747, 66.2951,
67.7269, 69.1416 and 72.5094, which are in good agreement with
the standard JCPDS file No. 30-1451 for ZnO and can be indexed as
the hexagonal wurtzite structure of ZnO having space group
P63mc. The average grain size of the particle has been evaluated
from FWHM that is full width at the half maximum of the reflec-
tion of maximum intensity in the XRD pattern using Scherrer’s for-
mula. The average crystallite size for NPs is and 31 nm and for NC
is 53 nm. The d spacing is calculated using Bragg’s diffraction law
2.2. Characterization
nk ¼ 2d sin h
ð1Þ
The Phase purity and crystalline size of FZNPs and FZNP/PANI were determined
The calculated d spacings for various planes are reported in Ta-
ble 1. The crystallite size was determined using Scherrer’s formula
by an XPERT-PRO X-ray diffractometer using Cu Ka radiation. Morphological prop-
erties of NPs and NCs were studied using a Scanning Electron Microscope (SEM)
QUANTA250 FEI D9393. Elemental analysis was done by EDX equipped with SEM.
TEM analysis was done by High Resolution Transmission Electron Microscopy
(HRTEM) and Small Area Electron Diffraction (SAED) using FEI Tecnai F20 Transmis-
sion Electron microscope. FTIR spectra were recorded with a Nicolet 5700 FTIR
spectrophotometer by KBr pellet method.
kk
P ¼
ð2Þ
b cos h
where p is the crystallite size, b is the full width at half maximum,
K = 0.9 and = 1.54 Å for Cu K radiation
K
a
2.3. Optical and photocatalytic studies
The lattice constants for FNZPs as calculated from XRD data
were a = b = 3.2492 Å and c = 5.2357 Å. XRD diffraction pattern of
FNZP/PANI (Fig. 1b) shows peak at about 2h = 25.82°, which is a
characteristic peak of PANI [15,16] which corresponds to (110)
plane of PANI [16] representing scattering from PANI chains at in-
ter planar spacing. The peak at 2h = 19° corresponds to (200) plane
of PANI. In case FNZP/PANI, peaks corresponding to diffraction
from (100), (002) and (103) planes of ZnO are retained. The other
peaks are not visible which may be due to low FNZP and PANI mo-
lar ratio. The d spacing for (100) plane of PANI in XRD pattern of
composite is 4.624 Å and for (200) plane is 3.438 Å. The composite
on a whole has a semi-crystalline structure.
The optical band gap was studied using UV spectrophotometer. 2 mg of sample
was dispersed and ultrasonicated in ethanol. UV–visible spectra were obtained
using double beam spectrophotometer. The photocatalytic efficiency of the samples
was studied for degradation of methylene blue as a pollutant in presence of natural
sunlight in a slurry type batch reactor. The slurry consisting of MB dye and catalyst
suspension was stirred magnetically. 0.25 mg/ml of photocatalyst (FNZP/PANI) was
added to aqueous solution of dye (1.5 ꢀ 10ꢁ5 M). Before exposing the solutions to
sunlight, they were kept in dark for 1 h to establish adsorption–desorption equilib-
rium. After intervals of time, aliquot of 3 ml was taken out and centrifuged to re-
move catalyst form suspension. The absorbance of MB solution was then
recorded using double beam spectrophotometer at 662 nm. The average intensity
of sunlight was recorded as 34 ꢀ 103 100 lx using Lux-meter. All experiments
were performed three times and average values were reported. The effect of initial
MB concentration on the degradation rate was also studied. For this 80
lM, 100 lM,
140 M and 160 M concentrations of MB were prepared. This is done to prove that
dye removal is not an adsorption controlled process (Langmuir–Hinselwood
l
l
3.1.2. FTIR analysis
The FTIR spectrum of Ni/Fe doped ZnO (Fig. 2a) has a strong
absorption band at 498.0 cmꢁ1 which is Zn—O stretching fre-
quency [17]. The peaks at 3401.3 cmꢁ1 and 1561.9 cmꢁ1 represents
OAH and C@O stretching modes respectively. Characteristic
mechanism).
2.4. Electrical studies
For electrical conductivity measurements, powdered samples of NPs were
pressed uniaxially into pellets of 1–2 mm thickness and 8 mm diameter by applying
pressure of 4 ton for 5 min. The pellets were sintered at 300 °C for NPs to get the
thermal stability. Fine quality silver paint was applied on both sides of the pellets
for good electrical contacts. DC electrical conductivity measurement was done
using Keithley 2611 SYSTEM source meter (electrometer) by two probe method.
For studying the dc conductivity of FNZP/PANI, pellet was formed without the bin-
der by applying high pressure of 6 ton for 5 min (sintered at 100 °C). The electrical
conductivity was then obtained using electrometer by four probe method.
2.5. Antimicrobial activity
The strains of E. coli (MTCC 739) were obtained from IMTech Chandigarh, India.
The Muller Hinton Broth (Analytical Grade) was procured from Hi Media, India.
Antibacterial activity of synthesized materials against E. coli was determined based
on batch cultures containing different concentrations of FNZPs in suspension (80,
100, 140, and 160 lg/mL prepared in dimethyl sulphoxide). After adding the sam-
ples, sterile conical flasks containing 200 mL Nutrient Broth medium were soni-
cated for 10 min to prevent aggregation of the NPs. The flasks were then
inoculated with 1 mL of the freshly prepared bacterial suspension (Colony forming
units 108) as per Mcfarlands standards [14]. The flasks were then incubated in an
incubator shaker at 200 rpm and 37 °C. Bacterial growth was measured by growth
curve method by measuring the increase in Optical Density (O.D) at 600 nm using a
UV spectrophotometer. A positive control (containing NPs and nutrient medium,
without inoculum) was also kept. The concentrations of FNZP/PANI used for testing
antibacterial susceptibility were 40, 60, 80 and 100
lg/mL.
Fig. 1. XRD pattern of (a) FNZPs and (b) FNZP/PANI.

S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
251
absorption peaks of PANI (Emeraldine form) and ZnO obtained
from FTIR spectrum of FNZP/PANI (Fig. 2c) are 658 cmꢁ1 for CAC
bonding mode of aromatic ring, 848 cmꢁ1 for CAH out of plane
bonding in benzenoid ring,1241 cmꢁ1 for CAN stretching of benze-
noid ring, 1375 cmꢁ1 for CAN stretching in the neighborhood of
quininoid ring [17], 3054 cmꢁ1 for Symmetric stretch vibration
band of methylene [A(CH2)nA] and methylA(CH3), 3266 cmꢁ1 for
interaction between ZnO and PANI by formation of hydrogen bond-
ing between HAN and oxygen of ZnO, 486 cmꢁ1 for ZnAO bond
stretching and 504 cmꢁ1 for FeAO bond stretching. The character-
by transition metal ions (bare ZnO absorb at 378 nm). However,
intensity of this peak decreases in case of UV–Vis spectrum of com-
posite (Fig. 5a). A higher visible absorption can be observed in case
of FNZP/PANI. The band gaps of nanoparticles and composite were
calculated using Tauc relation [20]
n
ah
m
¼ Bðh
m
ꢁ EgÞ
ð3Þ
where
a
= Absorption coefficient = 2.303 A/l, Eg = optical band gap,
is the photon energy, and n = 1/2
B = Band tailing parameter, h
m
for direct band gap. The optical band gap is determined by extrap-
istic peaks of PANI (Fig. 2b) at 1585 cmꢁ1, 1375 cmꢁ1, 1177 cmꢁ1
,
,
2
olating the straight portion of curve between (
= 0.
The band gap as calculated from Tauc plots (Fig. 5c) for FNZPs is
ahm) and hm when
1511 cmꢁ1 are shifted to 1582 cmꢁ1 1375 cmꢁ1 1135 cmꢁ1
, ,
a
1508 cmꢁ1 respectively. This shift in peaks of PANI may be due
to interaction between PANI chains and FNZP nanoparticles which
results in change in electron density and bond energies of PANI.
[18,19]
3.17 eV and for FNZP/PANI (Fig. 5d) is 2.70 eV.
The photocatalytic degradation of MB in presence of FNZP
and FNZP/PANI as catalysts was investigated under sunlight irra-
diation. The change in absorption spectra of MB in presence of
photocatalysts FNZP and FNZP/PANI are shown in Fig. 5c and d
respectively. Electron–hole pairs are generated during irradiation
of FNZPs with UV–Visible light, which further react with water
to produce hydroxyl and super-oxide radicals which disrupt
the conjugation in organic molecules such as dye. This mecha-
nism is represented in Fig. 6. Electrons and holes generated on
absorption of sunlight interact with water and oxygen to form
OH. which disrupts the conjugation in organic dye and may also
mineralize it. The mechanism also shows that PANI acts as
sensitizer.
The band gap of ZnO is 3.37 eV, which can be overcome by
absorbing UV and visible light. But photocatalytic activity is less
in sunlight (contains only 3–5% UV). The absorption is increased
on doping. The effect of transition metal ions dopants on the pho-
tocatalytic activity is the dynamics of electron–hole recombination
and interfacial charge transfer. The dopant ions can function as
both hole and electron traps or they can mediate interfacial charge
transfer. The photocatlytic efficiency can be further be enhanced by
incorporating the doped ZnO nanoparticles into polymer matrix as
polyanilne.
As visible from absorption spectra of dye the degradation in
case of FNZP/PANI is higher, it can be inferred that PANI acceler-
ates the photodegradation process. When the NC is illuminated
under natural sunlight, both FNZPs and PANI absorb the photons.
The conduction band of ZnO and the Lowest Unoccupied Molecu-
lar Orbital level (LUMO) of the PANI are equivalent in energy [21].
The electrons from LUMO of PANI are transferred to valence band
giving rise to a new band below conduction band, thus decreasing
the band gap and also enhance the photocatalytic activity. Con-
ductive polymers as PANI act as good hole conducting material.
These conductive polymers act as a stabilizer or surface capping
agents when combined with metals or semiconductor nanoparti-
cles. The disappearance of characteristic absorption peak at
662 nm after 5 h shows that dye has degraded. The% Degradation
of dye is calculated as
3.1.3. SEM/EDX analysis
Fig. 3a and b illustrates the SEM images of FNZP and FNZP/PANI
respectively. The SEM micrograph shows that FNZP nanoparticles
are spherical in shape with a little agglomeration. There is also
some porosity which may be due to sintering process. The SEM
micrograph of FNZP/PANI shows a hierarchical morphology as
compared to nanoparticles and has leafy flakes like structure. The
elemental analysis (EDX) of FNZP and FNZP/PANI is shown in
Fig. 3e and f respectively. The percentage composition of doped
samples is nearly close to the starting composition. The EDX report
of the prepared NC shows the successful incorporation of PANI on
to the FNZPs. The Figure shows the presence of C, N, Fe, Ni Zn and O
in the nanocomposite.
3.1.4. TEM analysis
The HRTEM pictures of FNZPs (Fig. 4a) show that the particles
have mixed shapes. The TEM micrographs reveal a wide distribu-
tion of hexagonal and spherical particles. The fringes in individual
NPs are clearly visible and SAED pattern (Fig. 4b) reveals the per-
fect crystalline structure. The TEM micrograph of FNZP/PANI com-
posite (Fig. 4c) shows that NPs are homogeneously dispersed in the
PANI matrix. Fig. 4d illustrates SAED pattern of FNZP/PANI. It
shows that the composite has a semi-crystalline structure. The
average particle size of FNZPs is 15–30 nm and of composite is
30–50 nm.
3.2. Optical and photocatalytic studies
The UV–Visible absorption spectrum of the FNZPs (Fig. 5a) rep-
resents a sharp absorption peak around 385 nm which is the char-
acteristic single peak of hexagonal ZnO NPs. But there is a shift in
the absorption towards the longer wavelength because of doping
Table 1
d spacings for various planes for FNZPs and FNZP/PANI.
C0 ꢁ Ct
S. no.
Diffraction plane for Fe0.01Ni0.01Zn0.98
O
d spacing (Å)
%Degradation ¼
ꢀ 100
ð4Þ
C0
1.
2.
3.
4.
5.
6.
7.
8.
9.
100
002
101
102
110
103
200
112
201
2.813
2.601
2.475
1.909
1.622
1.476
1.404
1.377
1.371
where C0 is the initial concentration of dye before illumination and
Ct after time t. The extent of degradation of MB (Fig. 7a) after 5 h of
irradiation in presence of FNZP/PANI was 99.47% while 79% degra-
dation is achieved in case of FNZP. The FNZP/PANI nanocomposite
degrades dye to 98.55% in just 2 h after which degradation rate is
almost constant and after 5 h of illumination the degradation per-
centage is 99.47%. Several reports claim that the rate of photodeg-
radation of various dyes fitted a pseudo first order kinetic model
[22].
Peaks for PANI
Fe0.01Ni0.01Zn0.98O/PANI) (plane)
d spacing (Å)
2h = 19.31°
2h = 25.72°
100
200
4.624
3.438

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S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
Fig. 2. (a) FTIR spectrum of FNZPs, (b) FTIR spectrum of PANI and (c) FTIR spectrum of FNZP/PANI.
FNZPs is 0.02037 minꢁ1 and for FNZP/PANI is 0.02887 cmꢁ1
which clearly indicates the degradation rate is faster in case of
FNZP/PANI.
To confirm that the degradation of MB in our experiment is due
to the photocatalytic process and is not any adsorption controlled
process, the Langmuir–Hinshelwood was used for verification
[23,24]:
lnðC0=CtÞ ¼ kapp
t
ð5Þ
where kapp is the apparent rate constant, C0 is the concentra-
tions of dye before illumination and Ct is the concentration of
dyes at time t. Fig. 7c and d shows that the linear correlation
of the plots of ln (C0/Ct) versus time for FNZP and FNZP/PANI
suggesting a pseudo first-order reaction. The value of kapp for

S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
253
Fig. 3. (a) SEM micrograph of FNZP, (b) SEM micrograph of FNZP/PANI, (c) EDX pattern of FNZP/PANI and (d) EDX pattern of FNZPs.
of nanocomposite is 1.65 ꢀ 10ꢁ2 S/cm which is far larger than of
FNZP (2.29 ꢀ 10ꢁ8 S/cm), though it is lower than of pure PANI.
This may be due to the partial blockage of conductive paths by
FNZPs embedded in PANI matrix for charge carriers which do
not have sufficient energy to hop between favorite sites [26].
The decrease in the conductivity of the nanocomposites as com-
pared to PANI was attributed to the increased charge carrier scat-
tering between doped PANI and FNZP. As FNZP nanoparticles
embedded in the PANI matrix interrupted the doping process,
interactions between FNZPs and PANI increased the localization
of charge carriers, and thus decreased the conductivity of the
composites. However DC conductivity of FNZP/PANI is manifold
as compared to FNZP.
1
1
C0
k
¼
þ
ð6Þ
kapp kK
Table 2 shows the variation of apparent rate constant with ini-
tial MB concentration. Fig. 7d illustrates the plot of 1/kapp against
C0 at various C0. A linear relationship between 1/kapp and initial
MB concentrations confirms the photocatalytic degradation of
MB by the FNZPs and FNZP/PANI follow the Langmuir–Hinshel-
wood model. The degradation process is purely a photocatalysis
reaction.
3.3. Electrical studies
The DC conductivity is measured using Keithley source meter.
The characteristic I–V (current–voltage) curve is obtained. Using
values of I and V the DC conductivity will be calculated by
formula
3.4. Antibacterial studies
The growth curve studies of E. coli in presence synthesized
NPs and NCs showed that these are effective in destruction of
bacteria. It was observed that a level of 80 lg/ml of FNZPs to-
tally inhibited the growth of general strain of E. coli throughout
It
VA
r
¼
ð7Þ
The DC electrical conductivity of FNZPs and FNZP/PANI at var-
the 24 h period of incubation (Fig. 8c). However FNZP/PANI at
ious temperatures is shown in Fig. 8a and b respectively. This
electrical conductivity depends on the intrinsic defects generated
during synthesis and by the presence of dopants. The oxygen
vacancies created during combustion process are responsible for
electrical conductivity. The increase of electrical conductivity
with temperature shows the semiconducting behavior of FNZPs
[25]. It was observed that at room temperature, d c conductivity
40
the inhibition was very slow for first 6 h. Composite well inhib-
ited the growth for 24 h at the concentration of 60 g/ml. As ob-
served 60 g/ml FNZP/PANI did results in high turbidity but
there was no apparent change over time, thus showed bacterial
inhibition. The death phase of the E. coli was observed after 18 h
of incubation. In tests, FNZP/PANI exhibited better bacterial inhi-
lg/ml inhibited the growth completely (Fig. 8d). However
l
l

254
S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
Fig. 4. (a) HRTEM image of FNZP (b) SAED pattern of FNZP (c) TEM micrograph of FNZP/PANI and (d) SAED pattern of FNZP/PANI.
Fig. 5. (a) UV–Visible spectrum of FNZP and FNZP/PANI, (b) Tauc plots for FNZP and FNZP/PANI, (c) absorption spectrum of MB in presence of FNZPs at various times and (d)
absorption spectrum of MB in presence of FNZP/PANI at various times.

S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
255
Fig. 6. (a) Extent of decomposition of MB with respect to time in presence of FNZP and FNZP/PANI (b) Ln Co/Ct vs time for degradation of MB by FNZPs (c) Ln Co/Ct vs time for
degradation of MB by FNZP/PANI and (e) Langmuir–Hinselwood plot.
Fig. 7. Proposed mechanism of dye degradation.
Table 2
Comparison of rate constants for various initial concentrations of MB.
bition as it is efficient in low dosages. The effective of FNZP on
microorganism can be explained on the basis of the oxygen spe-
cies (OHꢁ, H2O2 and O22ꢁ) released on the surface of FNZP, which
cause fatal damage to microorganisms. It can be inferred that
FNZP/PANI is a better antibacterial agent because low dosage
Initial concentration of MB
M)
kapp (minꢁ1
)
(l
Fe0.01Ni0.01Zn0.98
O
Fe0.01Ni0.01Zn0.98O/
PANI
15
50
100
140
0.020404
0.016189
0.012475
0.010611
0.022361
0.017106
0.012928
0.010985
(60
lg/ml) of sample is effective in inhibiting bacterial growth
for the complete period of incubation.

256
S. Kant et al. / Journal of Alloys and Compounds 578 (2013) 249–256
Fig. 8. (a) Variation of DC conductivity of FNZP with temperature, (b) variation of DC conductivity of FNZP/PANI with temperature, (c) O.D curves for bacterial growth in
presence of FNZPs and (d) O.D curves for bacterial growth in presence of FNZP/PANI.
[3] G. MacDiarmid, Curr. Appl. Phys. 1 (2001) 269–279.
[4] S.R. Kargirwar, S.R. Thakare, M.D. Choudhary, S.B. Kondawar, S.R. Dhakate, Adv.
Mat. Lett. 2 (6) (2011) 397.
4. Conclusions
In summary, novel FNZP/PANI nanocomposite was prepared by
free radical in situ polymerisation method. FTIR spectrum con-
firmed the bonding between FNZP and PANI. The nanocomposites
exhibited excellent photocatalytic efficiency against methylene
blue under sunlight. A whopping 99.47% dye removal was achieved
in 5 h of illumination in case of FNZP/PANI as photocatalyst. The
composite exhibits high electrical conductivity at room tempera-
ture thus enhancing the property of semiconductor metal oxides.
Remarkable antibacterial activity was also obtained because PANI
helps in formation of more reactive oxygen species. Thus synthe-
sized nanocomposite promises to be an effective hybrid material
for waste water treatment and as an excellent antimicrobial agent.
[5] A. Tiwari, R. Kumar, M. Prabhakaran, R.R. Pandey, P. Kumari, A. Chadurvedi,
A.K. Mishra, Polym. Advan. Techno. 21 (2010) 615.
[6] Y. Long, Z. Chen, N. Wang, J. Li, M. Wan, Physica B: Condens. Matter 344 (2004)
82–87.
[7] I.S. Lee, J.Y. Lee, J.H. Sung, H.J. Choi, Synthetic. Met. 152 (2005) 173–176.
[8] N.N. Mallikarjun, S.K. Manohar, P.V. Kulkarni, A. Venkataraman, T.M.
Aminabhavi, J. Appl. Polym. Sci. 97 (2005) 1868–1874.
[9] J.W. Gilman, Appl. Clay Sci. 15 (1999) 31–49.
[10] D. Porter, E. Metcalfe, M.J.K. Thomas, Fire Mater. 24 (2000) 45–52.
[11] M. Zanetti, S. Lomakin, G. Camino, Macromol. Mater. Eng. 279 (2000) 1–9.
[12] M.D. Bedre, S. Basavaraja, D.S. Balaji, D. Raghunanadan, A. Venkataraman,
Inter. J. Polym. Mater. 59 (2010) 531–543.
[13] D.Y. Godovski, Adv. Polym. Sci. 119 (1995) 79–122.
[14] P.R. Murray, E.J. Baron, J.H. Jorgensen, M.L. Landry, M.A. Pfaller, Manual of
Clinical Microbiology, ninth ed., ASM Press, Washington DC, 2009.
[15] S. Min, F. Wang, F.Y. Han, J. Mater. Sci. 42 (2007) 9966–9972.
[16] W. Feng, E. Sun, A. Fujii, H. Wu, K. Nihara, K. Yoshino, Bull. Chem. Soc. Jpn. 73
(2009) 2627–2633.
Acknowledgements
[17] N. Faal Hamedani, F. Farzaneh, J. Sci. Islam. Repub. 17 (3) (2006) 231–234.
[18] E.T. Kong, K.G. Neoh, K.L. Tan, Prog. Polym. Sci. 23 (1998) 277.
[19] P.R. Sumani, R. Marimathu, U.P. Mulik, S.R. Sainkar, D.P. Amelnerkar, Synthetic.
Met. 106 (1999) 45–52.
[20] Z. Niu, Z. Yang, Z. Hu, Y. Lu, C.C. Han, Adv. Funct. Mater. 13 (2003) 949–954.
[21] V.B. Patil, S.G. Pawar, S.L. Patil, J. Mater. Sci. Mater. Electron 41 (2010) 355–
359.
[22] L.X. Zhang, P. Liu, Z.X. Su, Polym. Degrad. Stab. 91 (2006) 2213–2219.
[23] J. Xu, Y. Ao, D. Fu, C. Yuan, Appl. Surf. Sci. 254 (2008) 3033–3038.
[24] J. Xia, A. Wang, X. Liu, Z. Su, Appl. Surf. Sci. 257 (2011) 9724–9732.
[25] J. Han, P.Q. Mantas, A.M.R. Senos, J. Eur. Ceram. Soc. 21 (2001) 1883–1886.
[26] B.I. Nandapure, S.B. Kondawar, M.Y. Salunke, A.I. Nandapure, J. Compos. Mater.
47 (5) (2013) 559–567.
We acknowledge NIPER, Mohali (INDIA) for HRTEM facility and
Department of Physics, H.P.U. Shimla and Shoolini University, So-
lan (India) for necessary facilities.
References
[1] S. Kango, S. Kalia, A. Celli, J. Njuguna, Y. Habibi, R. Kumar, Surface modification
of inorganic nanopaarticles for development of organic-inorganic
nanocomposites – a review, Prog. Polym. Sci, in press. <http://dx.doi.org/
10.1016/j.progpolymsci.2013.02.003>.
[2] A. Moezzi, M.A. McDonagh, B.M. Cortie, Chem. Eng. J. 185–186 (2012) 1–22.