Doctor of Philosophy In Physical Chemistry By Muhammad Aamir

Synthesis of Polyaniline Composites and Their Applications

A dissertation submitted to the Institute of Chemical Sciences, Bahauddin

Zakariya University, Multan in partial fulfillment of the

requirements for the degree of

Doctor of Philosophy

In

Physical Chemistry

By

Muhammad Aamir

ROLL NO. Ph.D.C-09-05

Reg. #: 99-icm-7

(2016)

Institute of Chemical Sciences, Bahauddin Zakariya University

Multan, Pakistan-2016

Dedicated to:

MY GREAT AND LOVING FATHER

ABDUL SALAM

AND MY KIND AND LOVING MOTHER FOR HER

MORAL SUPPORT, PRAYERS.

Declaration of Candidate

I hereby declare that the work described in this thesis was carried out by me under the supervision of

Dr. Ghazala Yasmeen, Associate Professor and Dr. Muhammad Naeem Ashiq, Associate

Professor of Institute of Chemical Sciences Bahauddin Zakariya University, Multan.

I also hereby declare that the substance of this thesis has neither been submitted elsewhere nor is

being concurrently submitted for any other degree.

I further declare that the thesis embodies the result of my own research or advanced studies and that

it has been composed by me. Where appropriate, I have made acknowledgement to the work of

others.

Muhammad Aamir

Declaration of Institute

This is to certify that this dissertation entitled “Synthesis of Polyaniline Composites and Their

Applications” submitted by Mr. Muhammad Aamir is accepted in its present form by the Institute

of Chemical Sciences Bahauddin Zakariya University Multan-Pakistan, as satisfying the partial

requirement for the degree of Doctor of Philosophy in Physical Chemistry.

Submitted through:

SupervisorI:

Dr. Ghazala Yasmeen

Associate Professor

Institute of Chemical Sciences

Bahauddin Zakariya University Multan

Supervisor II:

Dr. Muhammad Naeem Ashiq

Associate Professor

Institute of Chemical Sciences

Bahauddin Zakariya University Multan

Acknowledgements

All praises are for almighty ALLAH, the most kind, magnificent and merciful who gave me

strength, power, knowledge and above all good health to complete this work amicably. This work is

acknowledged to many people whose contribution to accomplish this work has been marvelous;

especially, my supervisors Dr. Ghazala Yasmeen and Dr. Muhammad Naeem Ashiq for

accepting me, giving me intellectual freedom in my work, engaging me in new ideas, and

demanding a high quality of work in all my endeavors.

I would like to thank to ICS (Institute of Chemical Sciences) of Bahauddin Zakaryia University

Multan Pakistan for providing me an opportunity to complete my Ph. D and administrative staff for

their cooperation and facilitating me during PhD studies.

I would like to thank my father, mother, brother, sister, and my wife for their endless love,

continuous moral supports, and helping me achieve this feat in my academic career.

I would like to thank Fahad Ehsan and Sana for their help in my research work. I would like to

thank my friend Sajid Abbas for his continuous motivations and supports. I am really grateful to all

of you.

Muhammad Aamir

Sr. No. Topic Page #

Abstract

Chapter 1 1-84

1. Introduction 01

1.1. Conducting polymers 01

1.1.1. Historical Background of Conducting Polymers 02

1.1.2. Conduction Mechanism 02

1.1.3. Applications of Conducting Polymers 03

1.1.3.1. Biosensors 04

1.1.3.2. Supercapacitors 05

1.1.3.3. Field Effect Transistors (FET). 06

1.1.3.4. Light Emitting Diodes (LED). 07

1.1.3.5. Solar Cell 08

1.1.4. Polyaniline 08

1.1.4.1. Structure of PANI 09

1.1.4.2. Applications of Polyaniline 11

1.2. Nanomaterial 12

1.2.1. Multiferroics 13

1.2.2. Ferrites. 14

1.2.2.1. Spinel Ferrites 15

1.2.2.2. Hexagonal Ferrites 18

1.2.2.3. Garnets 18

1.2.2.4. Ferrites Categories 18

1.2.2.4.1. Soft Ferrites 18

1.2.2.4.2. Hard Ferrites 19

1.2.3. Uses of Nanomaterials 23

1.2.4. Applications of Nanoparticles in Biology and Medicine 27

1.3. Polymer Nanomatrials Composite 29

1.4. Dyes. 35

1.4.1. Classification of Dyes. 35

1.4.2. Usage Classification. 35

1.4.3. Chemical Classification. 36

1.4.4. Dyes Importance and Applications 36

1.4.5. Hazardous Effects. 39

1.4.5.1.Toxicity of Methylene Blue and Methylene Orange 40

1.4.5.2.Removal Technique 41

1.5. Photodegradation 41

1.5.1. Mechanism of Photodegradation 43

1.6. Aim of Work 47

References 49

Chapter 2 85-94

2. Experimental 85

2.1.Chemicals. 85

2.2.Preparation of Nanomaterial 85

2.3.Preparation of Composite 86

2.4.Characterization 86

2.3.1. X-ray Diffraction (XRD) 86

2.3.2. Scanning Electron Microscopy (SEM) 88

2.3.3. UV-Vis Spectroscopy 88

2.3.4. X-ray Photoelectron Spectrometer (XPS) 89

2.3.5. Fourier Transform Infrared Spectroscopy (FTIR) 90

2.3.6. Photo-degradation Experiment. 91

References 93

Chapter 3 95-159

3. Results and discussion 95

3.1. UV/Visible spectroscopy 96

3.2. FTIR study 104

3.3. XRD 109

3.4. Scanning Electron Microscopy 115

3.5. XPS Study 120

3.6. BET 127

3.7. Photodegradation Study of Dyes 129

3.1.1. Influence of Reaction Time. 128

3.1.2. Effect of Nanomaterial (%) Age in Composite 138

3.1.3. Kinetic 140

Conclusion 154

Reference 156

Index of Figures

Figure No. Caption Page #

Fig. 1(a). UV/Visible spectra XRD patterns for PANI, nanomaterial and

PANI/NiFe1.2Zr0.4Co0.4O4 composites.

101

Fig. 1(b). UV/Visible spectra for PANI, nanomaterial and PANI/ NiFeZr0.5Co0.5O4

composites.

102

Fig. 1(C). UV/Visible spectra for PANI, nanomaterial and

PANI/BiAl0.3Mn0.3Fe0.4O3 composites.

103

Fig. 2(a). FTIR spectra of PANI and PANI/nanomaterial composite of

NiFe1.2Zr0.4Co0.4O4.

106

Fig. 2(b). FTIR spectra of PANI and PANI/nanomaterial composite of

NiFeZr0.5Co0.5O4.

107

Fig. 2(c). FTIR spectra of PANI and PANI/nanomaterial composite of

BiAl0.3Mn0.3Fe0.4O3.

108

Fig. 3(a). XRD patterns for PANI, nanomaterial and PANI/ NiFe1.2Zr0.4Co0.4O4

composites.

112

Fig. 3(b). XRD patterns for PANI, nanomaterial and PANI/ NiFeZr0.5Co0.5O4

composites.

113

Fig. 3(C). XRD patterns for PANI, nanomaterial and PANI/BiAl0.3Mn0.3Fe0.4O3

composites.

114

Fig. 4(a). SEM images of PANI, 117

Fig. 4(b). SEM images of Nanomaterial(NiFe1.2Zr0.4Co0.4O4) 117

Fig. 4(c). SEM images of composite containing 12.5% (NiFe1.2Zr0.4Co0.4O4) and

87.5%(PANI),

117

Fig. 4(d). SEM images of composite containing 25% (NiFe1.2Zr0.4Co0.4O4) and

75% (PANI)

117

Fig. 4(e). SEM images of composite containing 37.5% (NiFe1.2Zr0.4Co0.4O4) and

62.5% (PANI)

117

Fig. 4(f). SEM images of composite containing 50% (NiFe1.2Zr0.4Co0.4O4) and

50% (PANI)

117

Fig. 5(a). SEM images for PANI, 118

Fig. 5(b). SEM images for Nanomaterial(NiFeZrCoO4) 118

Fig. 5(c). SEM images of composite containing 12.5% (NiFeZr0.5Co0.5O4) and

87.5%(PANI),

118

Fig. 5(d). SEM images of composite containing 25% (NiFeZr0.5Co0.5O4) and 75%

(PANI)

118

Fig. 5(e). SEM images of composite containing 37.5% (NiFeZr0.5Co0.5O4) and 118

62.5% (PANI)

Fig. 5(f). SEM images of composite containing 50% (NiFeZr0.5Co0.5O4) and 50%

(PANI)

118

Fig. 6(a). SEM images for PANI 119

Fig. 6(b). SEM images for Nanomaterial(BiAl0.3Mn0.3Fe0.4O3) 119

Fig. 6(c). SEM images of composite containing 12.5% (BiAl0.3Mn0.3Fe0.4O3) and

87.5%(PANI),

119

Fig. 6(d). SEM images of composite containing 25% (BiAl0.3Mn0.3Fe0.4O3) and

75% (PANI)

119

Fig. 6(e). SEM images of composite containing 37.5% (BiAl0.3Mn0.3Fe0.4O3) and

62.5% (PANI)

119

Fig. 6(f). SEM images of composite containing 50% (BiAl0.3Mn0.3Fe0.4O3) and

50% (PANI)

119

Fig. 7(a). XPS spectra for Ni2p 123

Fig. 7(b). XPS spectra for Zr3d 123

Fig. 7(c). XPS spectra for Co2p 123

Fig. 7(d). XPS spectra for Fe2p 123

Fig. 7(e). XPS spectra for C1s 123

Fig. 7(f). XPS survey for PANI composite with 50% NiFe1.2Zr0.4Co0.4O4. 124

Fig. 8(a). XPS spectra for Ni2p 125

Fig. 8(b). XPS spectra for Zr3d 125

Fig. 8(c). XPS spectra for Co2p 125

Fig. 8(d). XPS spectra for Fe2p 125

Fig. 8(e). XPS spectra for C1s 125

Fig. 8(f). XPS survey for PANI composite with 50% NiFeZr0.5Co0.5O4. 126

Fig. 9(a). Influence of time on the photodegradation of MO by PANI/

NiFeZr0.5Co0.5O4Composites

135

Fig. 9(b). Influence of time on the photodegradation of MB by PANI/

NiFe1.2Zr0.4Co0.4O4 Composites

135

Fig. 9(c). Influence of time on the photodegradation of MO by PANI/


136

Fig. 9(d). Influence of time on the photodegradation of MB by PANI/


136

Fig. 9(e). Influence of time on the photodegradation of MO by PANI/

BiAl0.3Mn0.3Fe0.4O3Composites

137

Fig. 9(f). Influence of time on the photodegradation of MB by PANI/ 137


Fig. 10(a). First-order kinetic plot for the photodegradation of MO by PANI/


148

Fig. 11(a). Second-order kinetic plot for the photodegradation of MO by PANI/


148

Fig. 10(b). First-order kinetic plot for the photodegradation of MB by PANI/


149

Fig. 11(b). Second-order kinetic plot for the photodegradation of MB by PANI/


149

Fig. 10(c). First-order kinetic plot for the photodegradation of MO by PANI/


150

Fig. 11(c). Second-order kinetic plot for the photodegradation of MO by PANI/


150

Fig. 10(d). First-order kinetic plot for the photodegradation of MB by PANI/


151

Fig. 11(d). Second-order kinetic plot for the photodegradation of MB by PANI/


151

Fig. 10(e). First-order kinetic plot for the photodegradation of MO by PANI/


152

Fig. 11(e). Second-order kinetic plot for the photodegradation of MO by PANI/


152

Fig. 10(f). First-order kinetic plot for the photodegradation of MB by PANI/


153

Fig. 11(f). Second-order kinetic plot for the photodegradation of MB. 153

Index of Tables

Table No. Caption Page #

Table. 1(a) The amount of element (atomic%) for PANI/

NiFe1.2Zr0.4Co0.4O4Composites investigated from XPS analysis

122

Table. 1(b) The amount of element (atomic%) for PANI/

NiFeZr0.5Co0.5O4Composites investigated from XPS analysis

122

Table. 2(a) BET and Langmuir Surface area and maximum pore size of PANI/

NiFe1.2Zr0.4Co0.4O4Composites

127

Table. 2(b) BET and Langmuir Surface area and maximum pore size of PANI/

NiFeZr0.5Co0.5O4Composites.

128

Table. 2(c) BET and Langmuir Surface area and maximum pore size of PANI/


128

Table. 3(a) MO %age Degradation with time. 132

Table. 3(b) MB % degradation with time. 132

Table. 3(c) MO %age Degradation with time. 133

Table. 3(d) MB % degradation with time. 133

Table. 3(e) MO %age Degradation with time 134

Table. 3(f) MB % degradation with time 134

Table. 4(a)

First-order specific rate constant for k1, second-order specific rate

constant k2, and correlation coefficient R2

145

Table. 4(b)



145

Table. 4(c)



146

Table 4(d)



146

Table. 4(e)



147

Table. 4(f)



147

List of Abbreviation

PANI Polyaniline

MB Methylene Blue

MO Methyl Orange

NPs Nanoparticles

Abstract

Conducting polymers represent an important class of functional organic materials for next-

generation electronic and optical devices. Advances in nanotechnology allow for the fabrication

of various conducting polymer nanomaterials composites synthesis with the different methods.

Conducting polymer nanomaterials composites featuring high surface area, small dimensions,

and exhibit unique physical and chemical properties therefore they have been widely used for

various purposes such as, they can be used as photocatalyst

The present research work is divided in to two parts. First part of thesis deals with the synthesis

of three different series of Polyaniline (PANI) composites in which two are Zr-Co-substituted

nickel ferrite with formula (NiFe1.2 Zr0.4 Co0.4 O4) and (NiFe Zr0.5 Co0.5 O4), one with MnAl-

substituted multiferroics with formula (BiAl0.3Mn0.3Fe0.4O3). The synthesis of composites of

Polyaniline (PANI) is carried out with the variation of nanoparticles amount (12.5, 25, 37.5, and

50% w/w). These composites are characterized by different techniques such as Fourier

Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), UV/Visible, X-ray

photoelectron spectrometry (XPS), and scanning electron microscopy (SEM). The structure of

PANI/nanomatrials composites was confirmed by XRD analysis while surface morphology was

investigated by SEM analysis. The FTIR spectroscopy is used to identify their functional groups

present in PANI/NPs composites and the shifting of the peaks has been found towards higher

wave number side which exhibits the interaction between the polymer and the nanoparticles in

synthesized photocatalyst. In UV/ Vis study blue shift has been found which give the

information about the interaction between ferric ions of nanomaterial with nitrogen atom of

PANI, shortening in the conjugation length, and coordinating complex formation. The XPS

analysis has been carried out to determine oxidation states of the elements present in the

synthesized composites materials.

In the second part these synthesized PANI/NPs are used as photocatatlyst against toxic dyes such

as Methylene Blue (MB) and Methyl Orange (MO). These synthetic dyes are most widely used

in textile and leather tanning industries. These dyes are highly colored, toxic, and carcinogenic in

nature. These effluents released from the textile and leather tanning industries containing 1mg/L

of dye are enough to impart color to the water thus making it unpotable for daily use. The

technology used to treat dyes is based on physical, chemical, and biological methods.

Precipitation, coagulation, filtration, floatation, electrochemical degradation, and advanced

oxidation techniques are considered as chemical methods. Adsorption, reverse osmosis, and

ultrafiltration are treated as physical methods. Photochemical irradiation of toxic dyes in

presence of a photocatalyst is one of the alternative methods developed recently.

Theses composites are then used for the photoelectric degradation of methylene blue and

methylene orange from aqueous media under UV light. Effect of reaction time, NPs

concentration and the kinetics is studied. It has been found that the degradation of methylene

blue and methylene orange increase with the increase in nanoparticles concentration in the

composite material. This degradation rate has been found to be low for methylene blue which is

cationic dye as compare to the methylene orange.

The photoelectric degradation for both dyes is also examined under the similar conditions of UV

light by pure PANI and nanoparticles. The degradation rate has been found very low because

recombination of electron-holes occurs in pure PANI and pure nanomaterial very comfortably as

compare to composites in which it is strictly prohibited.

The NPs amount present in the composite shows remarkable influence on the degradation

efficiency. Through several groups of univariate experiments, the optimum PANI/ NPs

composite dosage of the photolysis process is found to be 0.2g at 40ml of 10-5M solution of both

dyes. The photolysis process is relatively fast at the initial stage up to 30 minutes and later it

become slow, moreover the degradation of both dyes is in accordance with the first-order kinetic

equation.

Chapter 1

This chapter covers the general introduction of polymers, conducting polymers, nanomatrials,

ferrites nanomaterials, polymer nanomatrials composite, photodegradation and the mechanism of

photodegradation.

1. Introduction

Polymer is a large molecule (macromolecule) consists of repeating structural units joined by

covalent chemical bonds. The word is derived from the Greek words (poly), meaning "many"

and mer meaning "part"[1].

1.2. Conducting Polymers

Conductive polymers are unique class of materials which may be named as synthetic metals who

associates the electronic properties of semiconductors and metals with the chemical applications,

electrochemical characteristics and mechanical features of polymers [2]. These organic materials

are true metallic conductors or semiconductors who conduct electricity. Their biggest advantage

is their processibility. They can be defining as; these are synthetics plastics in which high

electrical conductivity is associated with the mechanical properties like elasticity, malleability,

flexibility, etc. of plastics. It is also possible to polish up their properties by using the different

methods of organic synthesis [3].

The characteristics such as electrical conductivity and electrochemical characterizations (like

metals), mechanical strength and easiness of processing (like polymers) and option of both

chemical and electrochemical synthesis, make them valuable in extensive area of applications

[4].

1.1.2.1. Historical Background of Conducting Polymers

Excellent quantities of researches are in progress since 1977, when it became possible to conduct

the electricity from the conjugated polymer polyacetylene by doping with halogen [5-7]. It was

supported by Shirakawa et al when he successfully synthesis the conducting polymer

polyacetylene in 1977 [9]. Electrically conducting polymers have their interesting potential uses

in various fields of electrical and mechanical also, therefore they have got great attraction for the

new researchers [2]. Twenty five years of research work and 2000 Nobel Prize in Chemistry in

this field shows the importance of conducting polymers [8]. These have become one of the most

attractive subjects of investigations in the last few decades [10].

1.1.2.2. Conduction Mechanism

The conducting polymers which consist on large molecules have characteristics of interchanging

the single and double bond and electrons can travel from one end to the other end of polymer

chain through the stretched p-orbital system [11]. In this way they get unique optical and

electrical properties due to their π electron delocalization along the polymer chain [12].

Conducting polymers have sp2 hybridized π-conjugated polymer with a systematic alternating

system of single (C-C) and double (C=C) bonds leads to a lower band gap energy, Eg in the

delocalized π system [13]. Semiconducting and metallic organic polymers conductivity

generated due to some extent of sp2 hybridized linear carbon chains. Backbone of sp2 hybridized

carbons form by three in plane sigma-orbitals, one sigma-orbital is bonded to the hydrogen atom

and remaining two are bonded to the adjacent carbons atoms. The conductive polymers special

properties are generated by the fourth electron which remains in the Pz orbital and is decoupled

with the backbone sigma orbitals. In case of classical polymers, which behaved like electrical

insulators, such as polyethylenes, all valence electrons are engaged in sp3 hybridized covalent

bonded electrons, therefore there will be no movable electrons will available to participate in

electronic transport [14]. In the undoped state of conjugated polymers energy gap could be more

than 2 eV, this energy gap is huge in case of thermally activated conduction. Due to this reason

polythiophenes, polyacetylenes which are conjugated polymers shows low electrical conductivity

in the range of 10-10 to 10-8 S/cm in their undoped form. Even at very low level of doping (< 1 %)

the electrical conductivity increases in about 10-1 S/cm which are several orders of magnitude as

compare to pure polymer material. Therefore for different conduction polymers doping will

bring fullness of the conductivity at values near around 100-10000 S/cm. Highest reported value

for the conductivity of stretch oriented polyacetylene till now, with definite values, is around

80000 S/cm [15]. Some conducting polymers are as follows.

Figure 1.1 various conductive organic polymers structures. Polyphenylenevinylene,

polyacetylene, polythiophene (X = S) and polypyrrole (X = NH), polyaniline (X = N, NH) and

polyphenylene sulfide (X = S).

1.1.2.3.Applications of Conducting Polymers

Conducting polymers realized as new class of materials who possess not only the processing

advantages of polymers but it also demonstrates the conducting and mechanical properties of

metals [16].

As well, conjugated conduction polymers have numerous applications in all field of life. Some of

their current prospective and commercial applications of these polymers are supercapacitors, fuel

cells, storage batteries, electrolytic capacitors, [17], ion-specific membranes, sensors,

electrochromic displays, biosensors and chemical sensors, corrosion protection, transparent

conductors, electromagnetic shutters, EMI shielding, gas separation membranes, anti-static films

and fibers, conductive textiles, photoconductive switching, conductor/insulator shields, non-

linear optics, conductive adhesives and inks [18], electronic devices, and electroluminescence

etc. [19-21]. For the devices based on conducting polymers such as switchable windows and

mirrors, dynamic camouflage and electrochromic, have made the conducting polymer a new

center of research. This is the reason that all electro-active and conducting polymers can be

easily synthesis as compare to inorganic electrochromic materials and potentially electrochromic

materials, even the advantage of high degree of color tailorability is also suggested [22].

Conducting polymers application to use in some modern instruments is also discussed

1.1.3.1. Biosensors

The device in which biological sensing element is integrated within or connected to or transducer

is called biosensor. Its purpose is to generate digital electronic signals, and these digital

electronic signals will be related to the concentration of particular chemical [23].

Conductive polymers based biosensors have been used to sense an inducible nitric oxide

synthesis, peroxynitrite [24], superoxide [25], NADH [26] thrombin [27], DNA [28-29],

glutamate [30], heavy metal ions [31], etc.

A number of biological molecules, such as receptors, enzymes, cell, and antibodies, etc., can be

fixed in an appropriate matrix because they have very short lifespan in solution phase. The

enzymes activity decreases when the biological elements begins to immobilized against the

condition of environmental [32-33]. Conducting polymers have proved to be beneficial in

medical diagnostics because, they not only have ability to increase the stability, sensitivity and

speed of biomolecules, but also they have attained great attention as appropriate matrices for

biomolecules. [34-35].

Dopamine is a monoamine neurotransmitter of both the central and peripheral nervous systems

play important role in neural immune communication [36]. To determine simultaneous

voltammetric measurement of dopamine and ascorbic acid Ciszewskiet al. investigated different

polymer coatings [37] and introduced new carbon electrode materials [38]

1.1.3.2. Supercapacitors

The properties like long life cycle, simple principle, and great dynamic of charge propagation

have made the supercapacitors much more attracted in the recent area of development [39-40].

These were invented to provide the hundreds to thousands of Farads and initially these were

manufactured by carbons which have high surface area [41-42].

A type of supercapacitors (pseudocapacitor) forms which store the charge generated in response

to redox reaction which derives its capacitance in the bulk of a redox material and this fast redox

reaction [42-43] perform same capacitance i.e. pseudocapacitance. Pseudo-capacitor is the

capacitors which stores larger amount of capacitance per gram than an electrochemical double

layer capacitor the reason is that the majority of the material reacts. An example is a conducting

polymer (CP) of pseudo-capacitive material.

Now supercapacitors are focusing on the growth of modified, new and innovative electrode

materials with better-quality and performance. Supercapacitors electrode constituents are divided

into three categories: transition metal oxides, high-surface carbons, and conducting polymers

[44-45]. Conducting polymers increase the progress of device. The increase in energy stored

while reducing self-discharge is observed, when they passes through a redox reaction to store

charge in the main part of the material. In almost all inorganic battery electrode materials these

electrodes have well kinetics than others which are pseudo-capacitive materials therefore it can

be suggested that the gap in the middle of the batteries and double-layer supercapacitors can be

filled by conducting polymers [46].

To decrease the resistance, it is combined as inorganic-organic hybrid electrode material, it is

used amended membrane which is coated by the good conductive material (conductive polymer),

in this way it completely consumes its respective advantages [47-48].

Polyaniline is the one of the best and attractive p-dopablepolymer. For redox supercapacitors

synthesis of polyaniline by electrochemical procedures has suggested as an electrode material

[49-51]. Ryuet al. [52] created two types of supercapacitors, by doping of polyaniline with LiPF6,

These are of redox nature and are symmetric type, on the bases of two LiPF6 doped polyaniline

electrodes, and second one is of the hybrid nature and asymmetric type, on the bases of PANI-

LiPF6 and active carbon electrodes.

1.1.3.3. Field Effect Transistors (FET).

Conducting polymers due to low price and easiness of processing have advantages over the

conventional materials, for example silicon and germanium. Field-effect transistors (FETs) has

manufactured by organic or polymer-based semiconductors [53]. The classification of sensors on

the bases of work function modulation composed of three kinds of Micro Fabricated Devices

which are; “Chemically sensitive Diodes, chemically sensitive capacitors, and chemically

sensitive FET’s [55]. To distinguish whether the current runs through the silicon or through the

conducting polymer they are divided in two categories; (a) thin film transistors [56] and (b)

insulated gate Field-Effect Transistors are also included [57]. For the thin film transistors, its

conductivity is generated from electric fields when the current runs throughout a conducting

polymer or by the reaction with the analytes. Therefore it was purposed that the work function

and conductivity of the conducting polymer are two things on which reply signal depends. In

both these things conductivity of the conducting polymer do not effected but the interpreted

energy states can affected the work function values [58].

1.1.3.4. Light Emitting Diodes (LED).

Polymers can also manufacture for microlithography uses [59-60]. The polymer light-emitting

diodes (PLEDs) were studied by Burroughes et al. They suggested that when inorganic and

organic materials compared for LEDs, the polymer electroluminescence (EL) devices found the

several advantages of quick response times, process ability etc. and it is also possible by

changing their structure to get fin-tun their electrical characteristics and optical properties by

applying different methods of preparation [61-63]. The excellent promising potential for polymer

light emitting-diodes usage is shown by π-conjugated polymers and their derivatives for

example, poly(p-phenylenevinylenes) [64-65], poly(dialkylfluorenes) [66], and polythiophenes

[67], these are used extensively.

High chemical solidity and structural tailorability is shown by polythiophene which is a

conjugated polymer. It can be comfortably use to exploit for manufacturing the correct structures

with the targeted areas for the different physical properties such as color emission, transition

temperatures etc. [68].

1.1.3.5. Solar Cell

Several researches have been reported which prove that conducting materials are the basic

component of solar cells [69-70]. Easy solution processing capability, low-cost production, and

large applications in electronic devices, have made the polymer solar cells more popular [69-72].

Conducting polymers materials has gain remarkable attention due to their applications in the

production and design of low prices organic electronic and photovoltaic devices.

Low prices solution processing, lesser thermal budget with fast speed of processing is only

suggested by organic photovoltaic [73]. Poly (3 hexylthiophene) is one of the best

semiconducting polymers for the polymer solar cells [74]. Moreover to get the outstanding PV

properties the mixture of poly (3-hexylthiophene) and the C60 derivative is used which give

performance outside 5 % [75-78].

1.1.4. Polyaniline

Even though a number of conducting polymers have been manufactured as well as studied, but it

is till now, one of the best polymer having the top combination of environmental stability,

excellent and control conductivity with lesser price [2]. It is also one of the best materials, among

the family of conjugated polymer, which is air and moisture resistance in its either doped form

weather it is conducting or insulating form [79-81].

For more than a hundred years it is known as ‘aniline black’. It is by product which is formed

during the electrolysis on the surface of anode as undesirable black deposited. Simple way of

synthesis, manageable electrical conductivity with good resistance against environmental

conditions make polyaniline most favorable polymer among all other conducting polymers [82].

Polyaniline has taken great attention of the scientists only since the early 1980s; it is because of

rediscovery of high electrical conductivity [83]. It has a countless variation of potential uses with

batteries, sensors, separation membranes, and antistatic coatings [07, 84].

Polyaniline has potential use as electrochromic device, as corrosion protecting paint and as

sensor also. These applications make polyaniline highly beneficial and attractive to use in

electromagnetic shielding devices, solar cells, displays, lightweight battery electrodes, and

sensors [85]. PANI possess semiconducting properties, generally with inorganic semiconductors,

in reply to exterior effects by altering particular features for example, conductivity, density,

color, permeability to gases and liquids [86]

1.1.4.3. Structure of PANI

There is π-conjugation exist in conducting polymers through polymer backbone, which is formed

by carbon and hydrogen, in blend with heteroatoms such as nitrogen or sulphur. Polyaniline is a

classically phenylene base polymer, its properties such as protonation, de protonation and

various physicochemical can also detected by the existence of –NH–group which is chemically

flexible in the polymer chain edged on both side by a phenylene ring [82].

PANI exists in three forms, which are full oxidized that are called pernigraniline, the half-

oxidized form is called emeraldine base (EB) and completely reduced form is regarded as

leucoemeraldine base (LB). In all of three forms, it is also suggested that emeraldine is not only

the most stable form but it is also the most conductive form of PANI, which is when undergoes

from the process of doping (emeraldine salt) [87]. Emeraldine base structure is be made up of the

same sizes of amines (–NH–) and imine (=N–) locations [88, 89]. On the other hand both are the

nonconducting forms of PANI weather it is fully reduced leucoemeraldine base or fully oxidized

pernigraniline base [90]. The pernigraniline form of polyaniline is the only polymer; accept the

polyacetylene, who exhibits twofold degenerate ground state [91-93].

The general form of PANI consists of both reduced and oxidized units. The reduced units contain

two benzenoid rings with two amine groups, and the oxidized units contain one benzenoid ring,

one quinoid ring, and two imine groups. Variations in the ratio of oxidized and reduced units

within the polymer provide a wide range of different oxidation states for PANI. For example,

leucoemeraldine is fully reduced form containing only benzenoid ring structures, while

pernigraniline is the most oxidized form with two benzenoid and two quinoid structures. The

emeraldine form of PANI has equal amount of reduced and oxidized units, and is the most

conductive in comparison to other oxidation states [94].

Three benzene rings divided by amine (−NH) groups in all replicated unit with one quinoid ring

which is enclosed by imine (−N=) groups. In the polyaniline structure there are two couples of

carbon atoms in the ring and four π-electrons and quinoid ring present in polymer chain forms

double bonds with the nitrogens. All forms can occur in a base form and in several protonated H+

salt forms also [95]. The valuable transport properties are exhibited by the Emeraldine salt

(PANI-ES) or the conductive form of PANI [96].

It is consist of oxidized and reduced dimmer fragments, when it is in the form of the alternating

copolymer. The alternating copolymer transforms to a polyconjugated polyradical cation salt if

the imines nitrogen atoms undergoes protonation or dopation, and it is very close to a

stoichiometrical i.e. the molar doping ratio is near to 0.5. Then dopant counter anions become

stabilize with the average of two radical cation charge carriers per tetramer repeating unit) [97].

Conductivity of the polyamine changes with the number of electrons or level of oxidation and

the number of protons or amount of protonation [98]. PANI possesses controlled conductivity in

the range of 10-10 – 101 Scm-1.

Polyaniline almost composed of para-substituted monomer and have organized super molecular

structures. These factors in polyaniline are responsible for the high conductivity of macroscopic

sample and also the existence of elongated-polyconjugated system [99].

1.1.4.4. Applications of Polyaniline

In recent years many researchers has concentrated on the development of least price, printed

electrochemical sensor platforms for clinical diagnostics and environmental monitoring.

Considerably effort has been applied for consuming the redox properties of polyaniline. To get

the best sensing applications several groups have examined various mass-amenable fabrication

approaches to obtain suitable thin films of PANI. During this observation it was found that nano-

dispersions have shown a great deal of promise for sensing applications providing that they are

inkjet-printable. Two dimensional pattern, thickness, and conductivity can be finely controlled

the inkjet-printed films of polyaniline, and it highlight the level of precision achievable by inkjet

printing. Polyaniline can also be used in many other application areas such as energy storage,

displays, organic light-emitting diodes etc. [354]. There is several application of polyaniline in

industries and in our daily life. Few of them are discuses here.

The electrical conductivity of polyaniline can be controlled in wide area of range. Its

conductivity level as high as 100 S/cm and less than 10-10 to 10-1 S/cm can be achieved by

making the polymer blends in which polyaniline will be present in different composites.

Polyaniline based compositions can withstand against the high temperatures of 230-

240°C but for short time i.e.5-10 minutes and prohibited any significant change in their electrical

properties,

By using the polyaniline with different material it is possible to manufacture the

electrically conductive transparent thin films and coatings.

One of the best applications of these materials is that they are used in protection from

Electrostatic Discharge (ESD). During the handling of sensitive electronic components,

explosive or dry powder electrostatic discharge causes problems. The use of the controllable

conductivity material in ESD protection materials is one of the basic benefits of conductive

polymer technology.

In packing industry polyaniline is used in Injection molded antistatic products and also

for making the antistatic films.

Polyaniline has its application in electronics it is used in antistatic packaging of

components and also in the manufacturing of the printed circuit boards

1.1.2.Nanomaterial

One of the most popular areas among all recent developments and research topics in technical

disciplines the field of nanotechnology is at the top. It would include microelectronics, polymers

based biomaterials, polymer bound catalyst fuel cell electrode, polymer films formed layer by

layer by self-assembling, nanofibers of electrospun, and nanocomposites with polymer [100-

102].

Ferrites are divided into three groups hexagonal, garnet and spinel ferrite, this classification is

based upon their structure. Among all these, spinel ferrites are one of the most studied ferrites

because of their various applications in different fields. The chemical formula of spinel ferrite is

MFe2O4 in this formula, M represent divalent metal ions, it may be Co, Ni, Mn etc. Spinel

ferrites have two sub-lattice sites which are tetrahedral site represent as “A” and octahedral

represent as “B”. The accommodation of different cations having different valance at the

interstitial sites can bring extensive variation in the electrical and magnetic properties [103-104].

Each unit cell of spinel stricter has 56 ions, 32 oxygen and 24 metal ions. If M shows cations that

occupy tetrahedron sites and x is degree of inversion then ferrite can be represented by a general

formula (M1-xFex)[MxFe2-x] O4[105]. The transition metal ions in the spinels are capable of

possessing one or more oxidation states and they can occupy tetrahedral and octahedral positions

and the cations present in two different interstitial sites strongly effected on the physical

properties such as crystal structure, electronic conduction, and magnetism [106-114].

We are interested in the magnetic nanomaterials. The ferrites and multiferroics are the most

popular because of their chemical stability structural, corrosion inhibition large saturation as

alloys and e saturation magnetization and suitable to their counterparts such as metal and alloys.

1.2.1. Multiferroics

Multiferroics are the material which reveals two or more primary ferroic properties. This

definition was basically suggested by Schmid, he made efforts to characterize the materials and

study the effects that allow the formation of switchable domains [115,116]

Multiferroics have potential uses in future technology like information storage [117] sensors and

number of many other applications [118]; therefore they have got a significant attention. It is one

of the best property of multiferroics that they have inherent ferroelectric properties along with

ferromagnetic or ferroelastic characteristic. Magneto electric effect occurs in these materials and

magnetization is controlled by the applied electric field or the electric polarization is controlled

by magnetic field [119]. Multiferroics can be grouped in various ways according to different

characteristics. One method is to classify the materials according to the mechanism that drives

the ferroelectricity: proper and improper ferroelectrics [120].

1.1.2.2. Ferrites.

Magnetic materials which have combined electrical and magnetic properties are known as

ferrites. Iron oxide and metal oxides are the main constituents of the ferrites [126]. These are

ceramic materials which are non-conductive and ferrimagnetic in nature. These comprise of

various combinations of iron oxides such as Magnetite (Fe3O4) or Hematite (Fe2O3) and the

metal oxides like CuO, NiO, ZnO, CoO, and MnO. When ferrites are in magnetized state then all

the spin magnetic moments are not sloping in the same path, it is one of the major properties of

ferrites.

If M is stands for the divalent metal such as Fe, Mn, Co, Ni, Cu, Mg, Zn or Cd then ferrites can

be represented by general molecular formula of M2+O.Fe2 3+O3. A unit cell of spinel structure is

composed of on 8 molecules in which 32 oxygen (O2-) ions, 16 Fe3+ ions and 8 M2+ ions are

present in each unit cell. Structure of ferrites is organizes in such a way that 8 Fe3+ ions and 8

M2+ ions are positioned at octahedral sites and each one ion is encircled by 6 oxygen ions. [127].

Ferrites impact strongly on the characteristics of magnetic materials. At the room temperature

resistivity of ferrites fluctuate from 10-2 Ω-cm to 1011 Ω-cm, depending upon their chemical

compositions [126]. No material which have ferrites like wide ranging properties exists and

therefore ferrites are unique magnetic materials which find applications in almost all fields.

Preparation of ferrites are highly sensitive, it is strongly effected by sintering condition, amount

of constituent metal oxides used for the preparation, and other various additives include in

dopants and impurities [128-130].

Classification

Ferrites are categorized into three different types [131].

(1) Spinel ferrites (Cubic ferrites)

(2) Hexagonal ferrites

(3) Garnets

We shall concentrate on the topic of spinel ferrites nanocrystals because they are regarded as two

of the most important inorganic nanomaterials. Spinel ferrites properties like electronic, optical,

electrical, magnetic, and catalytic make them important and attract to study them. It is observed

that the majority of the important ferrites are spinel [132]. We shell discuses spinel ferrites in

detail because spinel ferrites are one of the main components of our research work.

1.1.2.2.1.Spinel Ferrites

Spinel or cubic ferrites [131] are the materials which have the general formula AB2O4 and these

are when crystallize they attain the spinel configuration. In the general formula “A" represents

the tetrahedral cation sites and “B” is for octahedral cation sites, where the “O” represents the

oxygen anion site. Spinel ferrites can also be represents by general formula MeO Fe2O3 or Me

(ІІ) Fe2 (ІІІ) O4, In this is representation Me (ІІ) is for divalent metal cation for example, Mn, Fe,

Co, Ni, Cu, Zn, Cd, Mg, or (0.5Li (І) + 0.5Fe (ІІІ)), and Fe (ІІІ) is the trivalent iron cation, their

crystallographic structure (MgAl2O4) is similar to mineral spinel which was purposed by Bragg

[133].

The use for spinel at microwave frequencies is most suitable because of its special characteristics

of unexpected values of electrical resistivity and lesser eddy current losses, therefore spinel is the

one of the most broadly used type among the ferrites [131]. When the unit cell of spinel ferrites

is discussed it is found that, it has cubic structure which is formed by eight MeOFe2O3 molecules

and consists of 32 of O2- anions. In this cubic structure oxygen anions built the close face-

centered cube packing which have 64 tetrahedral (A) and 32 octahedral (B) empty spaces, these

empty spaces are partially filled by Fe3+ and Me2+ cations [134].

There are 96 interstitial positions are present in the unit cell which are of two types, these are

occupied by metallic cations, 64 are at tetrahedral positions occupied by A and 32 at octahedral

sites occupied by B. This distribution of cations is depending up spinel structure weather it is

normal, mixed or inversed spinel, order or position of A and B which they occupied and types of

ions have also great impact on spinel structure [135].

Classification of Spinel Ferrites

Distribution of cations on octahedral (B) and tetrahedral (A) positions is different in spinels, this

distribution decide the class of spinel. In this, way spinel ferrites have divided in three classes.

(i) Normal spinel ferrites

(ii) Inverse spinel ferrites

(iii) Intermediate spinel ferrites

i) Normal Spinel Ferrites

When only one type of cations is located on octahedral (B) positions they will be called a normal

spinel. Divalent cations in normal spinel ferrites are located on tetrahedral (A) position while the

trivalent cations take the position at octahedral (B) sites. General formula used for the

representation of normal spinel is (M2+)A[Me3+]B O4. In this formula M represents the divalent

ions and Me for trivalent ions. In this formula, square brackets are used to represent the ionic

separation of the octahedral (B) sites. This sort of distribution happened in zinc

ferrites Zn+2[Fe+2Fe3+]O4−2.

ii) Inverse Spinel Ferrites

As compared to normal spinel in which only one type of cations are located on octahedral (B)

positions, but in case of inverse spinel, half trivalent ions located at tetrahedral (A) positions and

half are at octahedral (B) positions. There are some cations also left over which separated

randomly among the octahedral (B) sites. General formula used to represent the invers spinel is

(Me3+)A[M2+Me3+]BO4. Its example is Fe3O4 in which Fe which is divalent cations is situated at

the octahedral (B) positions [136]. In the inversed ferrites the magnetic moments is compensated

mutually by the half of Fe3+ is positioned located at A-sites and half of Fe3+ is positioned located

at B-sites. And resultant moment of the ferrite is appear due to the magnetic moments of bivalent

cations Me2+ located at the B-positions.

iii) Intermediate Spinel Ferrites

When the distribution of ions is intermediate between the normal and invers in spinel, these are

identified as mixed. Spinel is called mixed when there are unequal numbers of each kind of

cations are on octahedral positions. Classical example of mixed spinel ferrites are MgFe2O4 and

MnFe2O4 [137]. Generally it is observed that, the magnetic ions of A- sites and B-sites (AB-sites

interaction) interaction is the strongest. When we compare, it was found that interaction between

AA-sites ten times weaker than that of A-B site interaction whereas the BB-sites interaction is

the weakest once. The leading AB-sites interaction is recognized as ferrimagnetism which is

resulted from the complete or partial anti-ferromagnetism [138].

1.1.2.2.2. Hexagonal Ferrites

Went, Rathenau, Gorter & Van Oostershout 1952 and Jonker, Wijn & Braun 1956 were the first

how identified hexagonal ferrites. Hexa ferrites are hexagonal or rhombohedral ferromagnetic

oxides with formula M Fe12O19, where M symbolizes for an element. Oxygen ions have closed

packed hexagonal crystal structure. These are broadly used as permanent magnets and have high

coercivity. These have their good application at very high frequency. Hexagonal ferrites ions are

bigger than that of garnet ferrites. [131].

1.1.2.2.3. Garnets

Garnets ferrites general formula is Me3Fe5O12, in which Me is for rare earth metal ions. It

contains 160 atoms or 8 formula units in single cubic unit which can be described as a three-

dimensional arrangement of 96 O2- with interstitial cations. [139].

1.1.2.2.4. Ferrites Categories According to their Hardness

Ferrites are of divided in two classes i.e. hard and soft and this classification is based on the

tenacity of the magnetization, which tell their capability of magnetization or demagnetization.

Soft ferrites can easily magnetize or demagnetized but it is difficult for hard ferrites [140].

1.1.2.2.1. Soft Ferrites

The special property of soft ferrites is that they can easily magnetize and have low corrosive

field. Moreover they have high magnetization and broad applications in this field, it is also

observed that if and when hysteresis loop for soft loop is thin and long its energy loss will

minimum. It can be understand by taking the examples of nickel, iron, cobalt, manganese etc.

which have their applications in transformer cores, recording heads and microwave devices

[141].As compare to other electromagnetic materials soft ferrites behaves batter when they are

used over the wide frequency range in the sense of high resistivity and low eddy current losses.

It is the characteristic benefits which dominate the soft ferrites over all other magnetic materials

that they are unchanged over a wide temperature range and have high permeability. Mn Zn-

ferrites are among the most extensively used soft ferrites in various types of transformers and

magnetic recording heads [142].

1.1.2.2.2. Hard Ferrites

Hard ferrites have wide hysteresis loop and high coercive field e.g. alnico, rare earth metal alloys

etc. These are also used as permanent magnets and are difficult to magnetize or demagnetize

[141]. These are the hard ferrites that their introduction was greatly promoted the growth of

permanent magnet. These are ferrimagnetic in nature with fairly low remanence (~400 mT) as

compare to other materials which have coercivity of their magnets in the range (~250 kAm-1) that

is far in excess. The maximum energy product is found only in the range of ~ 40 kJm-3. To

moderate the demagnetization of fields these magnets can also be used and it also has its

applications in permanent magnet motors..

Lead over other Magnetic Materials

There are many magnetic materials such as metallic alloys, iron and can be used in electronics.

But they have high dc electrical conductivity and low dc electrical resistivity therefore they could

not be used at high frequency equipments for example, inductor cores used in TV circuit.

The reason is that heat is generated due to their low electrical resistivity induces currents when it

flow through the material. This phenomenon makes the material inefficient and wastage of

energy take place this wastage become increase at high frequency.

On the other hand, ferrites have high electrical resistivity therefore they can execute much better

at high frequencies. They also have high temperature stability which is their important and

additional characteristic. These characteristics of ferrites boost the usage of ferrites at high

frequency equipment, in wide-band transformers, and in a number of high-frequency electronic

circuits. One of the most imperative features of the ferrites is that they have low cost as compare

to other alloys and magnetic metals and when they are used in high frequencies equipment they

perform better comparative to that of other circuit components. When one wants a good

combination of low cost, best worth, and small volume at the frequencies range from 10 kHz to a

small number of MHz the performance of ferrites is found excellent.

Ferrites are imperative magnetic materials and have comprehensive uses in technology, mainly at

high frequencies. Including the high electric resistivity they also show good magnetic and

mechanical properties their largely applications due to their following properties

1- High flux transformers and low power which are used in television ferrites are their essential

part.

2- Manufacturing of inductor core in combination with capacitor circuits to use in telephone is

possible with soft ferrites.

3- Small antennas used in transistor radio receiver can only be prepared by winding a coil on

ferrite rod.

4- Ferrite materials are used in the manufacturing of nonvolatile memories used in computer

because of their high stability against vibrations and severe shock.

5- Ferrites have also their applications in microwave devices like isolators circulators, switches

etc.

6- Ferrites can also be used in high frequency transformer core and computer memories i.e.

credit cards, computer hard disk etc.

7- High frequency equipment like wide band transformers, high speed relays, and inductors are

made by nickel alloy.

8- At low dielectric values ferrites are used as electromagnetic wave absorbers.

9- Ferrofluids cool the coils with vibrations are used as a cooling material in speakers.

Ferrites are also used in various technological because of extraordinary electrical resistivity and

wide ranges of saturation magnetization. Ferrites have large technological applications such as

LPG gas sensor; humidity sensor etc. because of their good permeability, excellent

magnetization and little losses at higher frequencies [143-146].The combination of magnetic and

electrical properties of the ferrites with spinel structure makes them helpful in several

technological appliances. It is also possible to modify the basic electrical and magnetic properties

of ferrite to suit the required application; it can be carried out by several ways. One of the simple

methods for the modification of ferrite properties is to apply different synthesis methods by

optimizing the suitable parameters. Several chemical methods have been applied for the

preparation of ferrite nanoparticles. These methods includes sol-gel [147], micro emulsion [148],

chemical co-precipitation [149] etc. Stirring time and speed, fuel, metal nitrates to fuel ratio, pH

and preparative parameters have major effects on size and the properties of spinel ferrite

nanoparticles [150]. The most important parameters which strongly affected by the size of

magnetic material is increase in electrical resistivity, saturation magnetization, coercivity etc.

when nanoparticles are compared with the bulk material as the particle size reduces to nanoscale

[151]

The superior properties and applications of nano-size spinel ferrite in new and innovative fields,

for example, magnetic drug delivery, catalyst, sensors etc. have increased the much more interest

for researchers from last ten years [152]. It has been done lot of work by many workers on the

structural and magnetic characterization of spinel ferrites in the nano-size form [153-154].

Spinels of the type AB2O4 such as: MnFe2O4, NiFe2O4 and CoFe2O4 have got great attention

among the different ferrites, which are a main component of magnetic ceramic materials, due to

their extensive uses in several technological fields [155]. The soft ferromagnetic material

NiFe2O4 is one of the most important nano-size materials it crystallizes in a completely inverse

spinel structure with all nickel ions located in the octahedral sites and iron ions reside in

tetrahedral and octahedral sites [156.] exist in its cubic structure.

Proper and regular ferromagnetism which originates from magnetic moment of anti-parallel

spins is also shows by the NiFe2O4 [157-159].

The moderate saturation magnetization, high electrical properties, high magneto-crystalline

anisotropy, good mechanical properties and chemical stability among the different spinel ferrites

with inverse spinel structure cobalt ferrite (CoFe2O4) is the most promising magnetic materials

[151].

Several workers have done a lot of work on the synthesis and magnetic properties of spinel

cobalt ferrite nanoparticles [160, 161].

1.1.2.3.Uses of Nanomaterials [162]

Now days most current and modern uses of nanomaterial represent the evolutionary expansions

of present technologies: for example, the electronics devices size reduction. Underneath we list

some significant uses of nanomaterials.

i) Sunscreens and Cosmetics

The old chemicals used for UV shield shows poor long lasting stability. Titanium dioxide based

sunscreens have its numerous benefits and shows good UV defense property.

To reflect and absorb ultraviolet(UV) rays and also to transparent visible light nanosized

titanium dioxide and zinc oxide are presently used on large scale and shows great results, which

makes them more appealing to the consumers. Lipstick which is one of on ordinary used

cosmetic product is composed of nanosized iron oxide which is used as a pigment.

ii) Paints

Combining nanoparticles with paint technology can enhance their performance by converting

them in light weight and giving them diverse properties. The nanotechnology can provide a

superior solution to block light and heat entering through windows.

Coating is significant part in construction which is widely used to paint the buildings. The

purpose of coating is to create a protective layer and bound to the base material for desired

shielding of the surface with different functional properties. Nanotechnology with paint creates

the ability of self-healing and corrosion resistance under insulation. These coatings are

hydrophobic in nature and fight with water against the damage of the metal pipe; it acts as guard

to the metals from salt water attack.

iii ) Displays

Nanomaterials are key factor for the development of vast market of sharp brightness, flat-panel

displays which have their important applications in television screens and computer monitors.

For the next era of light-emitting phosphors, cadmium sulphide, zinc selenide, zinc sulphide, and

lead telluride nanocrystalline, which are synthesized by sol gel methods, will be the best

selection.

iv) Batteries

With the passage of time demand and growth of electronic devices e.g. remote sensors, laptop,

computer and mobile phone is increasing continuously, therefore, high energy density batteries

with lightweight demand which are used in these equipments is also increasing continuously.

Nanocrystalline materials synthesized by sol-gel method form foam like (aerogel) structure.

These are best nominees for separator plates in the batteries because they can hold significant

amount of energy than customary ones. Nickel metal hydride batteries have bright future,

because they require less and frequent recharging to run longer, these are prepared by

nanocrystalline nickel and metal hydrides and have bulky surface area.

v ) Catalysis

In general, nanoparticles have high surface area and provide higher catalytic activity. Catalysis is

essential for the good qualitative and quantitative fabrication of chemicals. Due to very large

surface to volume ratio nanoparticles work as efficient catalyst for certain chemical reactions.

For the new era of catalytic converters, platinum nanoparticles is going to be one of the best

considerations by reducing the amount of platinum required because of very high surface area of

nanoparticles. Several chemical reactions such as, reduction of nickel oxide to the base metal Ni,

are also carried out by using nanomaterials.

vi ) Medicine

With the help of nanoparticles application it has become possible to pointing the drugs to

specific cells. This property of nanoparticles has boosted the nanotechnology in medical field. It

is possible to avoid the higher dosage and lower the drugs side effects by decreasing the

consumption it can be done by studding the deposition of the active agent in the morbid section.

Reproduction or healing of damaged tissues can be achieved with the help of nanotechnology.

The usage of gold in medicinal synthesis is not new. In the Indian medical system called

Ayurveda, gold is used in a number of syntheses. One famous synthesis called Saras

watharishtam, recommended for the memory development. To improve the mental ability of

babies’ gold is also added in certain medicine syntheses procedures. Over 5000 years ago,

Egyptians used gold in dentistry. In Alexandria, to restore the youth, alchemists developed

energetic colloidal elixir, identified as liquid gold. In china, to replenish gold in their bodies,

people cook their rice with a gold coin.

vii ) Sensors of Gases

The gases like NO2 and NH3 can be simply detected on the basis of the variation in the electrical

conductivity in gas sensor, because due to charge transfer from nanomaterials to NO2 and the gas

molecules bind by the nanomaterials the concentration of holes in nanomaterials increases which

increase the conductivity which is readable by the gas sensor.

viii) Food

Application of nanotechnology is also useful in the food technology, it is when applied in the

manufacturing, process treatment, safety and packaging good results are obtained. Food

packaging quality can be improved by nanocomposite coating process, which is carried out by

placing anti-microbial agents directly on the surface of the coated film.

ix) Construction

It is possible with the help of nanotechnology to make construction faster, low-priced and safer.

In this modern era of nanotechnology it is much easier to create and complete the huge

skyscrapers quickly and at low price. Silica which is used in concrete as a part of the normal mix

since old time, now with the help of nanotechnology by adding nano silica in concrete it is

possible to enhance the mechanical properties of particle of packing. In this way it does not only

control the degradation of calcium silicate hydrate reaction occurs in the concrete but it also

prohibited the penetration of water in the concrete surface, enhancement in durability is resulted.

Strength of concrete can also be increase the by the addition of hematite (Fe2O3) nanoparticles.

Construction industry can also be make more durable by improving the strength of steel which is

extensively accessible material and has a main role in it, for example in the bridge construction

nano size steel can be used to get much better strength by using stronger cables of nano size

steel,

x) Agriculture

With the help of nanotechnology applications it is possible to positively modify the agriculture

sector completely and it is also possible to bring positive change in food sector from production

to transportation and even it is also possible to treat the waste material.

xi) Energy

The most advanced nanotechnology challenging projects associated to energy are the energy

storage and its conversion, energy saving and improved renewable energy sources. Today's best

solar cells only attain the 40 percent of the Sun's energy although they have several layers of

diverse semiconductors which are loaded together to absorb light at different energies. By using

nanostructures it is possible that nanotechnology could help to increase the efficiency of light

conversion.

1.1.2.4.Applications of Nanoparticles in Biology and Medicine

Nanomaterials have move in a commercial exploration era [162, 163]. Living organisms are

constructed with cells. These cells are 10 µm across and cell parts are in the range of sub-micron

size even smaller are the proteins size of just 5 nm. And this size is comparable to the

dimensions of least size synthetic nanoparticles. Not only the size dependent physical properties

of nanomaterials but optical [164] and magnetic [165] effects are also have the most useful

application in biological sciences. In a similar way to get the unusual optoelectronics, electronic

and memory devices hybrid bio-nanomaterials are widely used [166, 167].

Nanoparticles occur in the size which is suitable for bio tagging or labeling in protein. Size is one

of the leading characteristics of nanomaterial that they are rarely sufficient to use as biological

tags. In order to use nanomaterials for biological application, molecular coating or layer acting as

a bioinorganic boundary should be attached to the nanoparticle [168], or it should be able to

create the nanoparticles biocompatible monolayers of small molecules [169].

i) Cancer Therapy

The process of cancer cells destruction by the laser generated atomic oxygen (which is cytotoxic)

is called cancer therapy. A larger amount of a special dye that is used to produce the atomic

oxygen is taken in by the cancer cells when matched with a healthy tissue. Therefore, only

cancer cells are damaged then visible to a laser radiation. In this process the residual dye

molecules move to the eyes and skin and make the patient very sensitive to the daylight

exposure. This effect can make problem up to six weeks. This side effect can be avoided by the

use of hydrophobic version of the dye molecule was sealed off inside a porous nanoparticle

[172]. The dye remained trapped inside the Ormosil nanoparticle and could not spread to the

other parts of the body. Moreover, its oxygen generating ability would not affect and the pore

size of about 1 nm freely allowed for the oxygen to diffuse out at the same time.

ii) Protein Detection [173]

The understanding and the functionalities of proteins are very essential because, these are the

important part of the cell's language and structure, and it is extremely important for further

progress in human well-being. It widely used of the gold nanoparticles in immunohistochemistry

to recognize protein-protein contact.

There are some applications of nanomaterials in biology and in medicines are listed below:

iv) Fluorescent biological tags [174-176]

v) Delivery of drug and gene [177, 178]

vi) Bio detection of pathogens [179]

vii) Proteins Detection [180]

viii) DNA structure Probing [181]

ix) Tissue engineering [171, 182]

x) Tumour destruction via heating (hyperthermia) [183]

xi) Separation and purification of biological molecules and cells [184]

xii) MRI contrast enhancement [185]

xiii) Phagokinetic studies [186]

1.3. Polymer Nanomatrials Composite

MacDiarmid and Heeger were surprised to observed that when high quality films trans-

polyacetylene expose to bromine vapor at room temperature there is an increase in conductivity

take place and it was million times in a few minutes, this change was very which the exhausted

the electronics of the measuring instrument. Now days it is possible to achieve the conductivity

similar to that of copper by doping the best quality samples of polyacetylene in similar way. It is

polyacetylene which purposed a new theoretical model for research the metal insulator transition

in organic materials and their conduction mechanisms also. It is possible to convert the

polyacetylene in an insulator, semiconductor or full metal by changing the dopant material and

their concentration. It generated the practical view of low cost, lightweight electronic devices

idea in mind [187]. The composite materials having less than 100 nm at least from one

dimension with polymer matrix and filler particles are call polymer nano-composites. These

composites are needed because of their low density, extraordinary corrosion resistance, and

easiness of manufacturing etc. [188- 191]. It is the aim to reduce the price and upgrading in

stiffness of polymer material for this purpose presence of inorganic fillers into polymers for

marketable presentations is needed upgrading [192]. These composite materials represent a new

and attractive alternative to conventionally filled polymers. A characteristic feature of polymeric

nanocomposites is that filler particles are of nanometer sizes. Nowadays, most often used are

inorganic nanofillers including silicates, clays, carbon nanotubes and carbon nanofibers. Owing

to a large surface area of interactions between filler nanoparticles and a polymer a desirable

modification of material characteristics together with improved modulus and strength, toughness,

exceptional barrier characteristics, better solvent and heat resistance, reduced weight and

improved dimensional stability, induced electrical conductivity, thermal conductivity, scratch

resistance and other properties, can be achieved at low filler loadings (1÷5 wt. %) [193].The

composite materials, now days, shows progressive performance and play important role because

of their special properties of corrosion resistance and light weight characteristic. Composites

materials are commonly consist of polymers which have fibers or minor filler particles in their

matrix these are distributed toughly e.g. in plastic and paper calcite particles as fillers are used

commonly. The calcite not only reduce the price but also make its tensile strength stronger and

stiffness of the base resin which form the composite also increases therefore it exhibit the good

performance. It is essential the filler must be distributed in good manner in the polymer matrix to

avoid the creation of weaker region of consistency, where defects or flaws can be introduced

when stress is applied [194]. The polymers which have extensive application and low price filler

have become more popular and gain much attraction in this developing world. Many physical

properties of the materials for example, mechanical strength, and modulus and adhesion

performance are improved by introducing the inorganic mineral as fillers into the plastic resins.

[195]. Filler particles are also used in the polymer matrix for fulfilling the additional

requirements i.e. stiffing enhancement, decreeing dielectric loss or increasing the absorption of

infrared radiation capability of polymers filler particles are also used. For this purpose calcium

carbonate is one of the best easily available filler which can be uses for size and surface

treatment. . Moreover several kinds of particular precipitated calcium carbonate filler particles

have comparatively regular shapes [196]. To determine the properties of manufactured

composite materials it is the best way to know the polymer composite material synthesis method.

Normally to best known method for the preparation of polymer composite are the, in situ

polymerization and solution mixing. Polyaniline composites are one of the best examples of

polymer composites [197]. Attempts have been made for the development of nanoparticle

filled-polymer composites with better tribological presentation of the materials are undergoing

with growing of nano-phased materials in the recent ages. When it is compared to those

composites which are filled with microscale particles it is predictable that good tribological

properties can be achieved form the polymers filled in which polymer matrix are filled with

nanoscale fillers [198, 199]. It is also possible to fabricate the polymer composites 107with the

combination of inorganic material injection into the polymer matrix. The characteristics,

dimensions, shapes of inorganic fillers, and interfacial bonding strength also highly effected on

resulting polymer composites properties. It was suggested that major improvement in the contact

area between the polymer matrix and filler with decreasing filler dimensions or increasing filler

concentration is observed, which would effectively and greatly develop the sharing of the load

between the fillers and the polymer matrix [200]. The inorganic nanofillers which ranges from 1

to 50 nm were effectively combined with the polymeric matrix, to make stronger and increase

the ductile polymer with the additional better stiff and resistant for abrasion [201, 202].

Substantially, it is possible to improve stiffness and thermal stability of composites, by addition

of the ceramic nanofillers into the extra flexible and poorer thermal resistance polymers [203-

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206] and the added particles size, shapes, volume fractions and surface are area affect strongly

on the mechanical characteristics of the polymer nanocomposites. Now, several researches are

in progress to determine that how a single-particle size disturbs mechanical properties of the

composites [207-210]. It was discussed by Ho- Shino et al. [207], he studied the impact of shape

and size of particles of silica on the fracture toughness and strength particle matrix adhesion

which based on strength, he observed that increase of flexural and tensile strength occur with the

increase in specific surface area of particles Yamamoto et al. [208] also reported that the shape

and structure of silica particle have greatly influenced on the mechanical characteristics such as

tensile and fracture characteristic and fatigue resistance also. The inorganic nanometer particles,

such as SiC, SiO2, Si3N4 and ZrO2, when combined with different polymer material effects of

on the tribological characteristics of few polymers have. Wang et al. reported that [211-217] after

filling the Polyetheretherketone with different weight fractions of SiC, Si3N4, SiO2, and ZrO2

concluded that if filler addition is less than 10 % by weight it will enhanced the wear resistance

and compact the friction coefficient. Schwartz and Bahadur [199] studied the filling of the

polyphenylene sulfide with alumina nanoparticles and they confirmed the distribution of filler

particles in the polyphenylene sulfide matrix with scanning electron microscopy. Li et al. [218]

successfully filled the nano particles of ZnO in Polytetrafluoroethylene matrix. Petrovicova et al.

[219] found that the friction coefficient of the nano-composite formed by filling Nylon 11 with

silica was lower than that of the unfilled Nylon by filling Nylon 11 with silica. They also

observed that wear resistance improved with increasing the concentrations of nanoscale silica up

to certain optimum value. Similar studies were also carried out by Avella et al. [220] who filled

polymethylmethacrylate with nanoscale CaCO3 and he found an increased in abrasion resistance

with the increase of the filler content .And this increase rate was by a factor of 2% with 3%




CaCO3 by weight and Yu et al. [221] who studied the surface area and the bonding strength of

polyoxymethylene composite by filling the micrometer and submicron copper particles in

polyoxymethylene matrix and he concluded that at filler/matrix interface increase in surface area

and improved in bonding strength by of the submicron copper filler particles take place. [222]. It

shows that strong potential of polyaniline and its composites on a bulky scale for the industrial

uses [223-225]. Polyaniline and its derivatives also have been applied for anticorrosive purposes

by coatings it on metal surfaces [226-230]. But the problem is that pure coatings of polyaniline

and its derivatives undergoes from poor bond strength and low mechanical properties also [231-

232]. Polyaniline composites were also synthesized with different metals and these were coated

on various metals surface for corrosion protection after improving the anticorrosive efficiency,

mechanical properties and their adhesion strength [2, 233-234]. Wonderful developments in this

field have been evident and verified by the rapid advances of chemistry in the development of

nanoparticles over the recent years. Due to the exclusive mechanical, electrical, optical, and

thermal properties of composites by using nanomaterials, the concept of using nanoparticles as

fillers in polymer materials have taken the considerable attention of researchers [235-240].

Nowadays, polymer nanocomposite materials are coming with incorporation of nano

reinforcements into elastomers, which considerably enhance their thermal and mechanical

applications in conjunction with visible developments in linkage, rheological and processing

actions. Furthermore, better dispersion of these fillers within the matrix provides high

performance nano composites and also the properties of the nano scale filler are significantly

higher than those of the base matrix [241-242]. There are ranges of nanoparticles such as

alumina [243], Micro and nanosized silicon carbide [244], Silica [245], Zinc [246], calcium

carbonate [247], carbon black nanoparticles [248], etc., were also used as fillers to improve the



material characteristics for polymer nanocomposites. To improve the interfacial properties of

composites the performance of nanomaterials in epoxy adhesive was also investigated.

Consequently, nanoparticles with developed active surface composition will perform as stress

concentrators and a binding channel at the interphase. Moreover as a new material, these

nanoparticles have been widely used to progress the strength, toughness and stiffness of resin

composites [249]. In this way, the discovery and the subsequent use of carbon nanotubes to

produce composites, show some of the carbon nanotubes related characteristic which are

mechanical, thermal and electrical properties and apply to a new and exciting dimension of this

area [250-254]. Pavia and Curtin [255] has been made to elaborate the effects of polymer

reinforced nanocomposites after considering the above facts, an effort has been made to

elaborate the impact of polymer reinforced nanocomposites. Ferrites which represent special

class of materials have also used, because of their several functional applications, as for example

installations of magnetic devices in electronic, optical and microwave equipments [256-257]

Many divers topics exist in the field of nanocomposites which include the barrier properties,

composite reinforcement, flame resistance, and cosmetic applications also. It can be concluded

that phase divided polymer composites frequently attain nanoscale phase sizes; in this way

nanoscale level is observed in block copolymer domain morphology; asymmetric membranes

frequently have nanoscale annulled structure, interfacial phenomena involve nanoscale

dimensions in blends and composites and miniemulsion particles have their size below 100 nm.

[100-102, 258]. For the determination of quality and properties of the nanocomposite the

interfacial contact between nanoparticles and polymer matrix plays a critical role. In the

nanocomposites, the well-dispersed nanoparticles which are in close to the particle surfaces are

surrounded by polymer chains. If the surface of the particles has strong contact with polymer



chains then the polymer chain will lose some of their freedom of movement and a region of low

movement polymer will exist around each particle [260]. The polymer chains in this region have

different behavior from those in bulk form. It is obvious that the interaction region between

polymer chains and nanoparticles has a great impact on thermal and mechanical characteristics.

Surface functionalization of nanoparticles makes the interface between the polymer matrix and

the nanoparticles stronger. This can be used to optimize the properties of resulting

nanocomposites [261].

1.4. Dyes.

For the coloration of numerous material including paper, leather, fur, hair, foods, drugs, plastics

and textile materials dyes are used which are powerfully colored substances. These Dyes may

attach or retain in these materials in several ways e.g. by physical adsorption, by metal complex

formation or salt formation or it may also be attached by covalent bond formation [262]

1.4.1. Classification of Dyes.

Dyes are usually classified in two ways [263]:

1. Fist of them is it is classified by the application method of the dye e.g. direct dyes, acid dyes,

reactive dyes, vat dyes, disperse dyes, sulphur dyes, metal complex dyes, mordant dyes, basic

dyes and azoic dyes.

2. Second one is the classification of the dyes based on the chemical constitution of the dye

molecules e.g. azo dyes, triphenylmethane dyes, stilbene dyes, anthraquinoid dyes etc.

1.4.2. Usage Classification.

There is system of dyes nomenclature and terminology; therefore before considering the

chemical structures of the dyes briefly, it is much better to study the dyes classification by






process of their applications. This classification is based upon the treatment or usages principal

system, approved by the Color Index [264.].

1.4.3. Chemical Classification.

Classification by chemical structure is one of the most suitable systems for the dyes, which has

numerous benefits. First of them is that with the help of this system it is possible to readily

identifies dyes as be in the right place in a related group which has their individual properties, it

can be explained form the example of azo dyes which are not only strong, economical and good

in all-round properties. Second one is that there are, about one dozen, controllable number of

chemical groups. [265].

Azo dyes as compare to the other commercial dyes has been studied more than any other class

because it has over 50 % of all market shares then other commercial dyes. These dyes are may be

define as; those dyes which have at least one azo group are called azo dyes. In their structure azo

group is attached to two groups in which one or both may be aromatic. These are exists in trans

form one of which is at bond angle 120° with sp2 hybridized nitrogen atoms [264].

1.4.4. Dyes Importance and Applications (leather, textile, food, paper)

The most important industrial sector that uses the dyes is the textile industries. The dyes used to

dyeing the polyester and cotton blends, dyes are consider most important which are used in

dyeing the important textile fibers, it means dye importance is depend upon it application. Other

dyes used in textile sector for dying fibers contain nylon, polyacrylonitrile, and cellulose acetates

are also considered from the important class. Similarly those dyes which are used in high-tech

applications, such as in electronics, medical, and nonimpact printing industries are also

considered important once for example, the dyes used in electrophotography in both organic

photoconductor and in the toner, in ink-jet printing, and in thermal transfer and in direct printing



[267]. When we discuss about the classical applications, azo dyes dominate over the use of;

anthraquinone, phthalocyanine, triphenylmethane and xanthene.

i) Reactive Dyes.

The reactive dye which could react with cellulosic fiber was first discovered in 1956. For the

cotton fabrics, reactive dyes are highly desirable to from covalent bond formation between dye

and cellulose for the excellent wash fastness arising in the alkaline conditions at pH 11. Due to

this covalent bonds formation during the dyeing procedure, reactive dyes have property of high

wet fastness. In this way reactive dyes not only give full range of bright shades but also decent

wet fastness with excellent light fastness which is basic need of textile sector. One of its

evidence is that approximately one-third of the money spent on dyes has been spent on reactive

dyes. In spite all these benefits there are some limitations also regarding the reactive dye usages,

with their cost and alkali, they also have time-consuming uses process, and dye losses also take

place due to hydrolysis.

ii) Disperse Dyes.

These are nonionic dyes which are water-insoluble and from aqueous dispersion which are used

for the hydrophobic fibers. Mostly these are used for polyester and cellulose acetate and to a

smaller extent on nylon also. The particles of disperse dye should be as fine as possible in the

range of 400 – 600 for the efficient diffusion. These are frequently substituted azo,

anthraquinone or diphenylamine compounds which do not contain water solubilizing groups and

are non-ionic. [138].

ii) Direct Dyes.

Direct dyes are anionic dyes which are water-soluble, in the presence of electrolytes when dyed

from aqueous solution, these are functional and have high affinity for cellulosic fibers. General

usage of theses dyes are dying of paper, cotton and regenerated cellulose, applications of these

dyes for nylon is to lesser extent. For these dyes it is possible to develop the wash fastness

properties after certain treatment.

It is important to note that the discovery of direct dyes has eliminated the requirement of

mordents during the dyeing of cotton, because these have affinity for cotton [139]. Most of these

contain four to seven derivatives of benzene and naphthalene. To confer water solubility of dyes,

sodium sulphonate group, -SO3Na, which is attached to benzene and naphthalene rings is one of

the best substituent for direct dyes [54].

iii) Vat Dyes.

These are water-insoluble and are used for cellulosic fibers as soluble leuco salts after reduction

in an alkaline bath, for this purpose sodium hydrogensulfite is used frequently. As the alkali is

used along with the reductive agent therefore protein fibers are not suitable for these dyes. Due

to their fixation mechanism most of vat dyes have excellent wash fastness properties.

iv) Sulfur Dyes.

It is one of the minor groups of dyes compare to other dyes groups. These dyes in the presence

of reducing agent i.e. sodium sulfide are applied on the cotton from an alkaline reducing bath.

The important feature of this class of dye is that these are from and imperative from economic

point of view because of their excellent wash fastness characteristics of the dyeing and low

prices.

v) Cationic (Basic) Dyes.

These are water-soluble and have their applications in paper industries, modified polyesters, and

modified nylons. One of the basic applications of cationic dyes is that they are applied on wool

silk and tannin-mordant cotton, when brightness of shade needed more than the fastness to light

and washing. These are basic in nature and are also use to color the cations in solution.

Therefore, these are also referred to as cationic dyes.

vi) Acid Dyes.

The fibers are based on polymer chains containing free amino group, such as nylon, wool and

silk are used to dye with acid dyes. Because an ionic bond formation take place under acid

conditions and the strength of this bond gives the rapid rate of color development. These are

classified into leveling dyes, premetallized acid dyes and milling/super milling acid dyes.

viii) Solvent Dyes.

These are water-insoluble dyes and suffering from polar solubilizing groups, for example

carboxylic acid and sulfonic acid etc. Normally these are used for coloring gasoline, plastics, and

oils. These dyes are mostly contains azo and anthraquinone, but some time phthalocyanine and

triarylmethane dyes are also used.

1.4.5. Hazardous Effects

Textile industries effluents containing the dyes are going to become one of the most serious

environmental issues. Behind this, the reason is that, they are the major cause of high chemical

oxygen demand content, toxicity, and biological degradation [268]. These unspent coloring

materials are discharged in water without passing from any treatment plant there by growing

aquatic pollution. These organic dyes are extremely colored polymer and have low bio-

degradability, they travel for long distances in regular stream of water, hinders photosynthetic

action, prevent the development of aquatic biota by hindering out sunlight and using dissolved

oxygen and it also reduce the regeneration value of stream. In the tropical country like India,

sunlight can be conveniently exploited for the irradiation of semi-conductor because it is one of

the plentifully available natural sources of energy. [269-270] These dyes contain the large

amounts of benzene rings, amino groups, naphthalene nuclei and azo groups, among others,

these are very difficult to dispose efficiently and completely, unfortunately these are very

common in dye structures [271]. Methylene blue (MB) dye is one of the most difficult to degrade

among the various dyes, therefore it is normally use to assess the activity of a photocatalyst as a

model dye contaminant for both in visible and in ultraviolet light irradiation [272-274]

1.4.5.1. Toxicity of Methylene blue and Methylene Orange

The toxic effects of the discharge of colored compounds on the ecological systems in the

environment have attracted much interest. Compare to others, azo dyes and thiazine dyes are the

two families of dyes which can cause serious health risk factors [275-276]. There are certain

aromatic amines used in azo-dye synthesis have makes the cause of bladder cancer. Moreover it

was also evaluated after extensive studies and research over on the effect of, variety of

chemicals on animal that, aromatic amines and azo compounds are cause of carcinogenic [277]

Methylene blue is major cause of effluent toxicity [278], genotoxicity [279, 280] and it is the

reason of following diseases hematotoxicity [281], microbial toxicity;[282] , mutagenicity[283],

neurotoxicity[284], nucleic acid damage[285, 286], photodynamic toxicity[287], reproductive

toxicity[288], teratogenicity[289] Methylene orange is not only Carcinogenicity; [290-292.] but

it also make the cause of genotoxicity;[ 279, 293-295] and mutagenicity [283, 296-298]

1.4.5.2. Removal Technique

A number of classical techniques have been applied to treat industrial effluents, but each one has

its own some limitations [268, 300-305]One of the main techniques used for pollution removal

from waste water is adsorption [306] which is common now a days. It has some drawbacks,

especially if we are dealing with toxic compounds or micro pollutants, is that what we actually



achieve is to accumulate and transfer the pollution load from the aqueous to the adsorbent phase.

We do not eliminate the pollutants but simply transfer the problem. Spent of adsorbent is also

kind of another hazardous waste and various pollutants used which were adsorbed may suffer

violent exothermically with adsorbent and may cause of explosion danger. It is well known that

adsorption is always an exothermic and desorption can thus be produced by increasing the

temperature of the adsorbent. Since the loading of the adsorbate is reduced at higher temperature.

Other techniques such as precipitation coprecipitation [307-314] are also used. However, these

approaches have been used extensively, in spite of several shortcomings: high operational and

waste treatment charges, extraordinary ingestion of expensive chemicals and huge volume of

sludge production [315-319]. The main drawbacks of all these old fashion methods are difficult

separation i.e. filtering or centrifugation, waste formation from both sludge and liquid, and it was

also faced in many circumstances that poor adsorption capacity of adsorbent occurs [320].

1.5. Photodegradation

The combination of the semiconductors nanoparticles with polymers, plastic, glass and other

semiconductors has proved to be an important initial step for the fabrication of many photonic as

well as optoelectronic devices [321]. Various inorganic-polymer nanocomposites composed of

several number of blends of two or more constituents have gain progressive consideration in

today’s world due to their remarkable potential uses and physical characteristics [322, 323]. Not

only these particles also have the positive characteristics of both metals and polymers, but they

also show several new characteristics, which are different from the both pure polymer and metal

[324]. Those materials which possess the delocalized conjugated structures have been

extensively experimented in this regard because of their relative slow charge recombination and

their speedy photoinduced charge separation [325]. For the stable photosensitizers to adjust the

band gap conjugated polymers are used with inorganic semiconductors in the fabrication of

electronic, optical and in the electronic photoelectric conversion devices [326, 327]. These are

also good hole transporters and efficient electron donors upon visible-light excitation [328]. The

extraordinary absorption coefficients in the visible portion of the spectrum, unexpected

movement of charge carriers with the brilliant environmental stability is shows by the conjugated

polymers which have extended π -conjugated electron systems e.g. polyaniline polypyrrole etc.

[329]. Being a conducting polymer polyaniline (PANI) also have an extended conjugated

electron system, proved to be a promising candidate, it does not only shows the great movement

of charge carriers but also have excellent absorption coefficients in visible portion of light and

[330-332]. Whenever polyaniline undergoes through photoexcitation, weather it is in partially

doped form or undoped form in both states it performs as electron donors and also act as a good

holes conductor, and it can carry current with number of milliamperes [321-335]. The

polyaniline has its some properties which are similar to metals for example, magnetic, electronic,

and optical, as well as it also has the properties of conventional polymers like flexibility and

processibility [336]. PANI has capability to upkeep positive charge carriers along with negative

charge carriers due to the existence of conjugated -electrons beside the main polymer chain

[337], it can be used in synthesis of heterostructure nanocomposites. Polyaniline semiconductor

nanocomposites are known to possess quite different chemical, physical, optical and electrical

properties from those characteristic of the parent polyaniline due to the interaction of delocalized

carriers between semiconductor quantum dots and PANI [338-340]. These nanocomposite

materials play a promising role in the manufacturing those electronic devices which have good

combination of outstanding magnetic, electronic and optical characteristics of metals and

polymers [341-342]. The efficient and equal separation of photoinduced charges is essential for

photo voltaic and photocatalytic applications, which is only provided by nanocomposites which

have large surface to volume ratio [343-344]. Several different composites of

polymer/semiconductor with different combinations of the two components have also been

reported [345-349]. Several reports have described the synthesis of photoactive nanocomposites

of polyaniline (PANI) with semiconductors such as PANI/BiVO4 [321], PANI/SnO2 [350],

PANI/CdS [351,], PANI/V2O5 [352,] and PANI/Fe3O4/SiO2/TiO2 [344,]. F. Wang et al [353,]

prepared PANI-sensitized TiO2 composite photocatalysts to improve the photocatalytic

efficiency of TiO2 nanoparticles in which PANI extend the photoresponse of TiO2 for

degradation of methylene blue. For the PANI and TiO2 it has been reported that in the, in the

conduction band of TiO2 polyaniline injected the excited electrons due to π – π transition under

the visible-light radiation, in this way the electrons are transported to an adsorbed electron

receiver for the production of oxygenous radicals [354]. H. Xu et al [355,] used MnO2/PANI

composite for degradation of organic dyes and Z. Liu et al [356,] also used PANI coated

TiO2/SiO2 nanofiber membranes for the degradation of dye pollutant.

1.5.1. Mechanism of Photodegradation

Photocatalytic reaction using semiconductor powders can effectively degrade many organic

pollutants, and even makes the compounds to be completely mineralized [357-362]. Different

transient species, for example radicals generated by bond homolysis or bond heterolysis, i.e.

photoionization, etc., as well as a number of photophysical processes (fluorescence,

phosphorescence, etc.) [363] with hydroxyl radical (HO.) by various different ways, giving rises

to induced photodegradation [364]. In the phenomena of photodegradation it was suggested that

one of the best active species was O−2 or OOH. The atoms which have the greatest electron

density in the normal state transferred the electron from the dye to the semiconductor. And

electron transported from the dye to the semiconductor is similar to reach from the atoms those

which have the greatest electron density in the regular state. Later on, at semiconductor surface

this atom becomes the ultimate location for the attack of superoxide anions radicals [365] as

suggested by Panchakarla LS [366] degradation reactions occurred between the metal and liquid

interface. The phenomena occur in the degradation process is, if the energy of incident light

falling on the surface of the photocatalyst is greater than the energy of the threshold limit value,

the photogenerated electrons are transferred from the valance bond to the conduction band and

leaving the positive holes after them in the valence bone. These holes directly oxidize the

impurities which are confined on the catalyst surface by surface hydroxyl groups to produce

hydroxyl radicals (OH.)[367]. These hydroxyl radicals decompose the dye into non-toxic

products. In this way conduction bands electrons react with dissolved oxygen molecules to

generate the superoxide anion radicals and it create hydroperoxy radicals upon the protonation

[368]. Moreover large surface area and low band gap energy of nanostructures are highly

favorable for the generation of maximum number of electron (e−) and hole (h+) pairs. It will

prohibited the 23recombination of the e-- and h+ pairs inside photocatalyst material, in this way

photocatalytic activity will enhance significantly [369]. It has been confirmed that the both

electrons and hydroxyl radicals transform amine functional groups are present in nitrogen

containing aromatic compounds, when they undergoes through the photodegradation phenomena

[370-371]. In the previous reports [370, 372-374], it was suggested that the maximum N-de-

alkylation proceed through the rout of production of nitrogen-centered radical, in spite the

damage of chromophore structures of dye which is followed by the generation of a carbon-

centered radical [372-373]. In the beginning of 10first two decades, photodegradation

characterization of dyes was carried out by UV active photocatalyst. And the scheme of general


degradation of dyes by the UV-active catalyst involved the photon absorption by the

photocatalyst, which combine the charge distribution and the generation of active species on the

photocatalyst surface. It was be suggested that in this mechanism the key active species, which

formed by the oxidation of water molecules from the photogenerated holes, are OH . radicals, and

the initial attack of the dye molecules is consider as oxidative [373. 375]. In case of

disappearance of color of azo dyes reflects there is an attack on the azo bond (C-N=N-) [376,]. It

followed that the opening of the aromatic rings occurred [377-378], so it can also be pointed out

that frequently observation of aromatic amines or phenolic compounds as intermediate products

is also found. This opening of the aromatic rings yields several kinds of carboxylic acids; these

carboxylic acids are eventually decarboxylate by the “photo-Kolbe” reaction to produce CO2. It

is also important to note that azo dyes, which consist of phenyl azo substitution, naphthol blue,

chromotrope 2R, etc. when degraded by hydroxyl groups, produce benzene as final product

[379]. Dyes containing nitrogen may generate NH+4, NO−3 and even N2, it depends upon the

nitrogen atoms initial oxidation state. Generally NH4 is produced by the amino group which

consists of nitrogen in the -3 oxidation state. Once ammonium ion formed, it will gradually

oxidize into nitrile ions photocatalytically [380]. As compare to N2, which exists is in its +1

oxidation state, is one of the most preferred end-product in the degradation of azo bonds. To

enhance the light utilization efficiency, several approaches have been established to plan the

oxides structures and their properties, such as doping with metal and nonmetal elements,

combination with other semiconductor materials, sensitization by organometallic dye molecules,

etc.[381-388] The combination of the semiconductors nanoparticles with polymers, plastic, glass

and other semiconductors has proved to be an important initial step for the fabrication of many

photonic as well as optoelectronic devices [321]. Various inorganic-polymer nanocomposites

composed with diverse combinations of two or more components have achieved higher and

progressive attention in today’s world due to their remarkable physical characteristics and

potential applications [322-323]. They show many new characteristics along with the

advantageous properties of both the metals and polymers which are different from individual

single phases [324]. In this way, the formation of a stepwise band gap structure in the composites

with other semiconductor materials has been found to lead to a superior photocatalytic

performance because they reduced recombination rate of photogenerated electron-hole pairs

[389]. The delocalized conjugated structures materials have been extensively experimented

because of their relatively slow charge recombination and rapid photoinduced charge separation

[325]. It is also observed that the polyaniline functional group amine and imine are predictable to

have strong affinity with metal ions [391-393] and being a conducting polymer with an

extended-conjugated electron system, proved to be a promising candidate due to high mobility of

charge carriers and its high absorption coefficients in visible-light range [330-332]. It is reported

that polyaniline has electronic, magnetic, and optical properties like metals along with the

flexibility and processibility of conventional polymers [336]. The presence of conjugated-

electrons in the backbone of polymer chain generates in capability to support the negative charge

and positive carriers also [157]. It was also reported that it is one of the best characteristic of

polyaniline that upon photoexcitation in its undoped or partially doped states, it is good electron

donor and excellent hole conductor because of this reason, it can carry current with several

milliamperes [321,333-335] Polyaniline-semiconductor nanocomposites are known to possess

quite different chemical, physical, optical and electrical properties from those characteristic of

the parent polyaniline due to the interaction of delocalized carriers between semiconductor

quantum dots and PANI [338-340]. These nanocomposites materials are ready to plays a central

role in the manufacturing of electronic devices with combine superior electronic, magnetic and

optical properties [340-342]. The large surface to volume ratio in nanocomposites enables an

efficient separation of photoinduced charges, which is important for photo voltaic and

photocatalytic applications [343-345]. There have been several reports describing the synthesis

of photoactive nanocomposites of polyaniline (PANI) with semiconductors such as PANI/TiO2

[346], PANI/BiVO4 [347], PANI/ SiO2 [348,], PANI /SnO2 [349], PANI/ CdS [350], PANI/V2O5

[351] and PANI/Fe3O4/SiO2/TiO2 [352]. Pan Xiong [353] reported that nanomaterial alone is

inactive photocatalyst but the combination of metal nanoparticles with PANI leads to high

photocatalytic activity for the degradation of the dyes. The enhancement in photoactivity is due

to transportation of excited state electrons of PANI to the conduction band (CB) of nanomaterial,

and holes i.e. photogenerated holes in the valence band (VB) of nanomaterial and it is their

nonstop migration to the HOMO of PANI, which effectively inhibiting a direct recombination of

holes and electrons.

1.6. Aim of Work

Owing to the rapid industrialization in recent decades, a huge amount of toxic effluent is being

discharged into various water bodies on a daily basis. These ongoing processes pose a serious

problem for the availability of safe water for drinking, household uses, agriculture, farming, etc.

Therefore, there appears to be an intimate shortage of clean water supply, which highlights the

urgent need for the purification of water, making waste water treatment an important issue of

concern.

A wide range of methods and technologies have been used to remove organic or inorganic

pollutants from water and waste-water to reduce their impact on the environment. These

methodologies involve adsorption on organic or inorganic materials, photocatalytic degradation,

oxidation processes, microbiological, or enzymatic decomposition. Of these, semiconductor

photocatalysis has been widely applied as a “green’’ technology for purification of air and the

elimination of organic contamination of water, and has become one of the most important

applied facets of heterogeneous catalysis.

Semiconducting metal oxide nanoparticles have long been explored as a photocatalytic material

for the degradation of pollutants. TiO2 has attracted considerable attention its photocatalytic

properties in their water splitting experiment. Similarly many other, metal oxide nanoparticles,

such as have been used to degrade non-biodegradable pollutants via photocatalytic routes.

My aim of study is to synthesize polyaniline nanocomposites with nano ferrites and multiferroics

and to study the application of these samples as photocatalyst for photo degradation of dyes. As

some dyes are very toxic so it is necessary to remove these dyes. First part deals with the

characterization of these samples and 2nd part deals with study of photo degradation of dyes in

the presence of our synthesis photocatalyst under the UV light.

As PANI (polyaniline) has also shown good potential for adsorbing dyes from the effluents. It

contains a number of imine and amine groups. PANI or nanomaterial alone are not a good

photocatalyst because in the presence of UV light electrons-holes recombine as they generate but

when they combined in the form of composite, recombination of electrons- holes is prohibited.

This phenomena is the basic reason of photodegradation of dyes

On the other hand, the photodegradation methodology is becoming popular now-a-days, because

of its cost effectiveness, low cost and user friendly/eco-friendly nature.

Chapter 2

Experimental

In the present study 12 samples of PANI/nanomaterial composites are prepared. It is done by

preparing three series of nanomaterial and the preparation of nanocomposites is carried out by

adding the nanomaterial during the preparation of polyaniline. For this purpose following

procedure is adopted.

2.1. Chemicals

The chemicals used in the synthesis of polyaniline and their composites with nanomaterial were

Bi(NO3)3 (Merck, ~75 %,), MnCl2.4H2O (Sigma-Aldrich, 98%), Al(NO3)3.6H2O (sigma-Aldrich,

99%), Aqueous NH3 (BDH, 35% purity). Fe(NO3)3·9H2O (98 %, Aldrich), Co(NO3)2·6H2O

(96%, Harris Reagent), NiCl2·6H2O (>99.5%, Merck), ZrOCl2·4H2O (96%, BDH), Aniline

chloride (99%, Merck), Ammoniumperoxy disulfate (97%, Merck), methanol (99.8%, Merck)

and acetone (98%, Merck), Methyl orange (92%, BDH), Methylene blue (95%, Merck). These

were used as such without further purification.

2.2. Preparation of Nanomaterial

All samples of nanomaterials were prepared by the chemical co-precipitation method. For this

purpose the stoichiometric molar solutions of metal salts were prepared in the deionized water

for each sample separately. Then the metal salts solutions of required samples were mixed in a

beaker and heated up to 60oC with continuous vigorous stirring. Ammonia solution (2M) was

added drop wise under the vigorous stirring to achieve the pH 11.0. The mixture was stirred

continuously for further 4 hours to obtain the homogeneity in the samples. The brown color

precipitates were obtained after addition of precipitating agent and were washed repeatedly with

deionized water until the pH reduced to 7.0. The precipitates were dried in an oven at 100oC and

finally annealed at 850oC in a box furnace (Vulcan A550) for 8 hours. The obtained powder was

used for further analysis.

2.3. Preparation of composite

The 0.2M aniline chloride solution was taken in a beaker and in this beaker weighed amount of

nanomaterial powder was added. After that 0.2 M ammonium peroxydisulphate was added in the

solution mixture drop wise with continuous stirring for 4–6 hours at temperature of 2-5°C.

Polymerization of aniline chloride was allowed to take place in the presence of fine graded

nanomaterial particles. The resulting precipitates were filtered and washed with acetone and

finally with deionized water until the filtrate becomes colorless. Acetone is used to dissolve any

unreacted aniline chloride. After washing, the precipitates were dried at 60–70°C in an oven. The

dried samples were grinded into a fine powder in a agate mortar pestle. These materials were

stored in desiccator and were used as photocatalyst for the degradation of methylene blue.

2.4. Characterization

2.4.1. X-ray diffraction (XRD)

For powder X-ray diffraction (XRD) analysis BRUKER D8 focus X-Ray diffractometer was used

to determine the purity and phase of substituted ferrite, it consists of Cu (K alph) as radiation

source at 40 kV and 40 mA. This technique is established on the Braggs law of diffraction. The

experiments executed at room temperature. The crystallite size of samples was calculated by

Scherer’s equation.

τ =Kλ

βCOSθ

Where τ is the mean size of the ordered (crystalline) domains, K is a dimensionless shape factor,

λ is the X-ray wavelength, β is the line broadening at half the maximum intensity (FWHM) in

radians and θ is the Bragg angle.

Electron beam after emitting the X-rays tube accelerated by high voltage field and are bombards

on target. A continuous spectrum of X-rays is produced after hitting of electrons with atoms in

the target and its speed becomes slow, which is named as Bremsstrahllung raditation. The high

energy electrons through the ionization process, emits inner shell electrons from the atoms. After

filling a shell from free electron, the X-ray photon is released having the energy characteristic to

the target material. Generally targets used in X-ray tubes include Cu and Mo, which emit 8 keV

and 14 keV with corresponding wavelength of 1.54 Å and 0.8 Å respectively.

X-rays first and foremost act together with electrons present in the atoms but the intensity

distribution of the waves is strongly modulated by diffraction of the waves cause by different

atoms present in the crystal. In this way it produces the diffraction of the waves in same periodic

manner. In this way measuring of diffraction pattern helps us to realize the distance between the

crystal planes [1-2].

Structure of polyaniline has been clarified by many researchers in the last thirty years [3-4].

However, the structural characteristics were investigated more in detail by Pouget et al. [5-6]

They reported two separate classes of emeraldine characterized by two different structures.

2.4.2. Scanning electron microscopy (SEM)

The surface morphology of the synthesized composite was determined by using field emission

scanning electron microscopy (HitachiS-4800 FESEM).

In the supervision of Max Knoll work for research and improvement on the electron microscopes

began in the 1920s. It was Ernst Ruska who worked for the improvement of electron lenses at the

Technical University of Berlin, Germany, in 1928 [7]. Ernst Ruska’s work was vital for

construction of an electron microscope in which lenses were required to channel the electrons of

the beam. Manfred von Ardenne invented the first scanning electron microscope in 1938 [8], it

generates the image of the sample with the help of electrons that gives to viewer the impression

of three dimensions, [9]. Scanning electron microscope has superior magnifying power which

could be applied to the study the structure of various materials [8].

Scanning Electron Microscopy (SEM) works by directing a beam of electrons to produce an

image from the surface of an article. This device is capable to describe an image with a range of

1 to 5 micrometers (10-6m) and exhibit the spatial differences within a material [10]

2.4.3. UV-Visible Spectroscopy

UV-Visible spectroscopy is a trustworthy and perfect analytical laboratory duty procedure that

permits for both qualitative and quantitative analysis of a substance.

Those atoms which absorb the light in the UV and visible regions of the electromagnetic

spectrum UV-Vis spectroscopy probe their electronic transition of molecules. The absorption of

UV and Visible light by different species can be define as, the species which have extended

system of alternation double and single bonds they will absorb UV light, and species having

color they will absorb visible light. In this way, it makes UV-Vis spectroscopy applications over

wide range of samples in multidiscipline fields [11]. For synthesis and photocatalytic

applications of materials, the Ultra-violet Visible (UV-Vis) Spectrometer is indispensible. It is

one of best application is that it identity the possibility of using the materials for photocatalytic

purpose either in the UV or visible light range, therefore we can suggest that UV-Vis spectra

define the material uniquely. To be more specific, the UV-Vis Spectra give the information

necessary to decide the maximum wavelength (minimum frequency and energy) required in the

incoming light source in order to excite the photocatalyst. The spectra generated here is due to

the optical transitions of electrons from valence band to conduction band. The UV-Vis spectra is

also a signature for a molecule with conjugated pi-electrons such as MO and MB dye, the test

dyes we used to evaluate the photocatalytic properties of Composite in this project. From the

spectra, we can decide important information like the maximum absorption wavelength of the

test dyes solutions, and evaluate any change in the absorbance of the dyes after irradiated for

certain period of time.

In this project, the UV-Vis transmission spectra of the synthesized composites arrays were

recorded by the UV-Visible/NIR spectrophotometer (Lambda 750 Shimadzu) over wavelength of

300-800nm, in order to determine the proper wavelength of the incoming light source. The UV-

Vis absorption spectra of MO and MB solutions before and after irradiation were also obtained

using the same equipment, as described in detail in the following section

2.4.4. X-ray Photoelectron Spectrometer (XPS)

The oxidation states of the elements were determined by using ESCALAB 250Xi X-ray

photoelectron spectrometer (XPS) analysis. The UV-irradiation was provided by a high pressure

mercury lamp (OSRAM 300 W).

XPS works on the basis of the photoelectric effect [12]. When a photon impinges upon an atom,

the energy of the photon might be totally transferred to an electron and excite the emission of the

electron from the atom. In XPS, X-ray as the irradiation source, can penetrate the sample on the

scale of 1000 eV are only able to penetrate less than 10nm. In XPS, only the photoelectrons

possessing characteristic emission energies will contribute to the photoemission peaks, while

electrons emitted form the surface zone that have lost some energy due to inelastic interactions

will form a scattering background. The process shows that the binding energy of the electron in

the atom is determined by the initial state and final state of the electrons. The core electron of

element has a unique binding energy, which can be seen as a “fingerprint”. Hence through the

analysis of the binding energy of defined elements, the chemical composition of a sample can be

obtained. Upward shifts in binding energies result from a decrease in electron density around the

nucleus (i,e from oxidation), whereas downward shifts result from an increase electron density

around the nucleus. The binding energy is also determined by the final state which is mainly

dependent on the relaxation effect in solids.

2.4.5. FTIR (Fourier Transform Infrared) Spectroscopy

FTIR spectroscopy is a good selection to study the molecular structures and their bonding

both for organic and inorganic materials. It can also identify the unknown elements present

in the specimen. The working principle of FTIR is that, every group of atoms in molecule

and their bonds vibrate with specific and characteristics frequency. Molecules of the

material absorbed the infrared radiations of the same energy which is the characteristics of

that material. Spot is inserted on sample for the modulation of IR beam.

There are different ranges in which the atoms shows different peaks due to vibration in FTIR

spectra e.g. adsorption bands appears in the range of 4000-1500 wave-numbers normally

revealed by functional groups CH3, N-H, C=O, OH< etc. and 1500-400 wave-numbers regions

are referred as finger print region. Compound quantitative concentration is determined by

measuring the area under in characteristics IR region curve.

2.5. Photodegradation Study

In the photodegradation study, 40 mL of methylene blue (MB) solution (10-5 ML-1 ) was taken

Four samples containing 40 ml of MB and 0.2g of each composite having different Nps 12.5%,

25%, 37.5% and 50%wt were taken as photocatalyst with dyes solution. After every 30 minutes

the dye solution was taken out from the photo reactor and centrifuge at 2000 rpm. The

absorbance of the solution was measured at wavelength of 665nm which is the λmax of methylene

blue. Similar procedure was repeated for methylene orange (MO) at λmax value 464nm.

The concentration of the compound in the solution is determined by absorbance because both of

these are directly proportional each other, as described by the Beer-Lambert Law:

A = εbC (2)

Where A is absorbance (no units), ɛ is the molar absorptivity (L mol-1cm-1), b is the path length

of the sample solution in the cuvette (cm), and C is the concentration of the compound is the

solution (moles L-1). The photodegradation efficiency can be calculated by the equation

Efficiency = Ci − Cr

Ci × 100 (2)

Where ci is the initial and cr is the remaining concentration of the dye MO at 464 nm as

measured by the UV-Vis spectrophotometer.

Chapter 3

Results and discussions

In the present study 12 samples of PANI/nanomaterial composites are prepared. It is done by

preparing three series of nanomaterial and the preparation of nanocomposites is carried out by

adding the nanomaterial during the preparation of polyaniline. Conformation of formation of

composite is done by using different characterization such as FTIR study, UV/Visible

spectroscopy, XRD, and XPS. After the confirmation of formation of composite from these

characterizations, we carried out its surface study by using the BET and Scanning electron

microscopy. The surface study indicates the formation of pores and sites which can be

available not only for the adsorption but also cause of increase in surface area.

Organic dyes which may be cationic or anionic in nature have large applications in textile

industry such as methylene blue and methylene orange. Including their positive usage they

also have their some negative aspects such as carcinogenic nature of these dyes is one of the

worst impact on human bodies when these dyes injecting into river, stream or underground

water. To reduce or minimize this impact of dyes, we used our synthesized catalyst in the

presence of UV light for their degradation and find application for degradation of both types

of dyes positive results.

3.1. UV/Visible spectroscopy

The UV/Visible spectra for PANI, NiFe1.2 Zr0.4Co0.4O4 and its composites are shown in Fig.

1(a). It is clear from the figure that three distinct peaks at 373, 417 and shoulder at 526 nm

were observed for pure PANI. The peaks appeared at 373 and 417 nm correspond to exciton

absorption of the quinoid ring and the π–π* transition of the benzenoid ring, respectively [5-

6.]. The peak at 417 is recognized to the localized polarons and characteristic of the

protonated polyaniline [7]. The shoulder at 526 nm was for the benzenoid to quinoid ring

excitonic transition [8] and also corresponds to the n-π* transitions of quinine imine groups

[9]. In UV spectra of nanocomposites when nanomaterial particles were dispersed in the

PANI matrix, a significant change was observed measured in the absorption spectra. The

shapes of UV spectra of nanocomposites were similar to those of pure PANI but certain

shifting in the peaks from 373 to 337, 417 to 396, and 526 to 480 was observed. The shifting

of peaks towards high energy and shorter wavelength increases with the concentration of

nanomaterial in composites. The spectral changes to the lower wavelength of the composite

samples indicate that the coordination of the nanomaterial particles to the nitrogen atoms

permitted the nanoparticles to interact with each other through the π-conjugate chain and also

indicates the formation of a complex between the polyaniline and the nanoparticles [10].

UV/visible spectra of all, PANI/nanomaterial composites samples shows that the intensity of

π–π* transition peak at 417 nm and excitonic transition peak at 526 nm increased compared to

that of pure PANI.

This increase in intensity of peaks suggests that there is interaction between dopant metal

complex and the polyaniline backbone chains which increases the number of charge carriers

[11]. This increase in number of charge carriers was fairly high in the excitonic transition peak

(526) as compare to π–π* transition peak which shows low trend. It indicates the presence of

interaction between the nanoparticles and quinoid rings in polymer chain which effect on

excitonic peak and resulted in a possible complexation [12].

UV/Visible spectra for the second series of PANI, NiFeZr0.5Co0.5O4 and its composites are

shown in Fig. 1(b). In the combine spectra of PANI, nanomaterial, and PANI/ NiFeZrCoO4

composite shifting of peaks towards the shorter wavelength is observed in case of composites.

The increase in intensity of peaks indicate the presence of interaction between dopant metal

complex and the polyaniline main carbon chain, in this way increase in the number of charge

carriers take place [10]. It also indicates that the coordination of the nano particles to the nitrogen

atoms permitted them to interact with each other through the π-conjugate chain and formation of

a complex between polyaniline and nanomaterial particles [11]. Compared to PANI, the peak

shift from 417 nm to 402 nm indicated that PANI is protonated in the synthesized composite and

confirmed the strong interaction between the PANI polymer and nanomaterial. Similar results

were also reported by V. H. Nguyen for the carbon nanotubes/polyaniline nanocomposites [13].

In the 4th sample of the series it was also observed that not only peak at 526 nm of benzenoid to

quinoid ring excitonic transition become stronger but it also shifted to 512 nm and becomes

invisible due to shielded by a new absorption peak at 561--594 which is characteristic peak of

pure nanomaterial. It verifies that it is not a simple mixing process between the PANI and

nanomaterial and the resulted PANI/nanocomposite could be best selection as photocatlysis

material. These results well match with the already reported for PANI-TiO2 by R. Yang, et, al.

[14].

The UV/Visible spectra for PANI, multiferroics and its composites are shown in Fig. 1(C). It

was observed that all characteristic peaks of PANI present in PANI/nanomaterial composite

along with some certain shifts of peaks , but there are certain shifts of peaks related to PANI was

observed. The shifting of peaks slightly towards lower wavelength side is observed; especially

emerging of bands at 370 wavelengths is prominent. The bands shifting in the spectra of

PANI/nanomaterial composite indicate that nanomaterial interacts strongly with PANI and

shows the influence of doping on composite spectra. Moreover it also exhibit the free carrier tail,

which indicates the conversion of localized polaron to the delocalized polaron free carrier tail

absorption similar result were also reported by Patil et, al. [15].

When spectra of nanocomposite are compared with pure PANI blue shift is observed. This blue

shift of absorption bands is evidence of interaction between ferric ions of nanomaterial with

nitrogen atom of PANI. It also confirms the presence of nanomaterial in the nanocomposites

[16]. This shift also shows shortening in the conjugation length that reported previously [17] or

may be the coordinating complex formation between NPs and PANI chains. The blue shifted

may depends on nanomaterial particles concentration in composite and concentration of

nanomaterial particles also affected on redistribution of polaron density in the band gap of PANI

emeradine. The blue shift and change in the intensity of absorption spectra of composite

suggested strong interaction between PANI and nanomaterial [18-19]. The spectral changes

indicate that the coordination of the dopant particles to the nitrogen atoms permitted the

nanoparticles to interact with each other through the π-conjugate chain and the formation of a

complex between the polyaniline and nanoparticles [10].

These blue shifts indicate that there may be an increase in band gap energy which is due to an

increase in the torsion angle between adjacent rings. This blue shift also confirms the

incorporation of nanoparticles in PANI matrix and make the causes of the change in

delocalization of electrons in PANI structure i.e. energy gap variation between HOMO and

LUMO.

With the increase in weight percent of the nanomaterial particles in PANI matrix, increased in

charge carrier scattering between PANI and nanomaterial particles take place and the shift in

bipolaronic band towards shorter wavelength side is also observed. Similar results were also

reported by [20-21].

These band gap transitions in the composite indicate the presence and participation of extra

powerful photogenerated holes and electrons in the photocatalytic reactions [22]. This blue shift

may be due to enhance the absorption of photocatalyst has great oxidation-reduction potential

and its characteristic expand its photocatalytic activity [23]. Confidently binding of nanomaterial

particles or metal ions with the polyaniline chain is also confirmed by the shifting of peaks

toward shorter wave length.

The coordinate bonding take place between the nanomaterial particles and PANI which is

responsible for charge transport phenomenon [24]. This charge transport phenomenon can be

explained on basis of the fact that, the charge carrier species are only electrons and metal-

polymer interface contains different Fermi levels (EF). These EF levels maintained a balance

between donor-receiver in semiconductor and in metal which are joined each other through a

flow of carriers of the metal for the semiconductor [25].

Combine spectra of samples containing pure PANI, nanomaterial, and PANI/nanomaterial

composites plots shows that intensity of π–π* transition peak at 417 nm and excitonic transition

peak at 526 nm increased compared to that of pure PANI. This increase in intensity of peaks may

be due to interaction between dopant metal complex and the polyaniline backbone chains. There

is an increase in number of charge carriers take place [11] However, this increase in intensity of

peaks was low in the π–π* transition peak while this increase was quite high in the excitonic

transition peak (526). It shows that there is some interaction between the nanomaterial with

quinoid rings located in the polymer chain, this interaction affect the excitonic transition peak

and resulted in a possible complexation [12]. Furthermore decrease in intensity of combine

absorption spectra with the increase in concentration of nanomaterial in composite was also

observed which may be due to strong interaction between nanomaterial particles and PANI [21-

26].

400 600 800

300 400 500 600 700 800

PANI

A-1

Ab

so

rba

nce

(a

.u)

A-2

A-4

Wavelength(nm)

NPs

A-3

Fig. 1(a). UV/Visible spectra for PANI and its composites (PANI) = PANI, (A-1) = 12.5%

NiFe1.2Zr0.4Co0.4O4, (A-2) = 25% NiFe1.2Zr0.4Co0.4O4, (A-3) = 37.5% NiFe1.2Zr0.4Co0.4O4, and

(A-4) = 50% NiFe1.2Zr0.4Co0.4O4

300 400 500 600 700 800

C1

C2

C3

Ab

so

rba

nce

(a.u

)

C4

PURE NANO

Wavelength(nm)

PANI

Fig. 1(b). UV/Visible spectra for PANI and its composites. (PANI) = PANI, (C-1) = 12.5%

NiFeZr0.5Co0.5O4, (C-2) = 25% NiFeZr0.5Co0.5O4, (C-3) = 37.5% NiFeZr0.5Co0.5O4, and (C-4) =

50% NiFeZr0.5Co0.5O4.

300 400 500 600 700 800

300 400 500 600 700 800

B-1

PANI

B-2

B-3

Wavelength(nm)

B-4

Absorb

ance(a

.u)

nano

Fig. 1(C). ). UV/Visible spectra for PANI and its composites (PANI) = PANI, (B-1) = 12.5%

BiAl0.3Mn0.3Fe0.4O3 B-2) = 25% BiAl0.3Mn0.3Fe0.4O3, (B-3) = 37.5% BiAl0.3Mn0.3Fe0.4O3, and (B-4)

= 50% BiAl0.3Mn0.3Fe0.4O3.

3.2. FTIR study

Fig. 2(a-c) shows the FTIR spectra of PANI and PANI composites. The peaks for polyaniline

and PANI composites are seems at the same region except that few more peaks are added in

figure print region of polyaniline/composite spectra, which indicate the presence of metals and

metal bonds. Infrared spectrum of the polyaniline shows six basic peaks which are the

characteristics peaks of polyaniline located at the positions 3415, 3340-3000, 1564, 1496, 1304,

1210, and 590-700 cm-1. A broad absorption band in the region of 3000 to 3340 cm-1 is

recognized to the protonation of amine functional group at polymer and presence of emeraldine

salt also. [32].Which is the stable and most conductive form of PANI when doped, as compare to

other oxidation states of PANI [33]. The high frequency strong bands at 1564 and 1496 are due

to the presence of the quinoid ring and the benzenoid ring respectively [34]. The peaks at 1304

cm-1 evident to the presence of N-H bending and the peak observed at 1210 cm-1 indicate the

presence of symmetric component of the C-C or it may also due to the C-N stretching modes

[35]. Interaction of water with the surface of polymer is also observed by the O-H stretching

mode. A small peak appear at 3415cm-1 represented the O-H group stretching of O-H, H-bonded

single bridge, it also shows that there may be some impurities of the moisture contents in our

samples. The C-Cl stretching peak arises in the region 590-700 cm-1[35] indicate the some

presence of monomer aniline chloride used for preparation of aniline chloride.

The FTIR spectra of the both PANI/Zr-Co substituted composites are similar as shown in the

Fig. 2(a-b). The spectra of the composites show some additional peaks in addition to the pure

PANI peaks which confirm the formation of composite with spinel ferrites. Spinel ferrites shows

two high frequency absorption bands in range of 800-400 cm-1 due to tetrahedral and octahedral

M-O stretching vibrations respectively [36]. The band at 435.93cm-1 for the presence of NiO [37]

and the band at 1076.8 cm-1 are attributed to the existence of Co-substituted spinel ferrites in the

composites structures [38]. The composite spectra also indicate the bands around 540-466 cm−1

which are assigned to Fe-O stretching [39].

In case of PANI/nanoferric composites as shown in the Fig. 2(c) the peaks observed in the ranges

of 500, 689, 745 cm-1 are specified for metals. The peak at 500 cm−1 is for the stretching

vibrations of Bi-O [40-41] and peak at 689 cm-1 is due to A1- 0 stretching [54]. Mn–O band

appears at 745 cm−1 in [42] and Fe-O stretching band around 540-466 cm−1 [43] in composite

spectra.

When the FTIR spectra of pure PANI and PANI/composites are compared, it is observed that the

peaks which are corresponding to pure polyaniline are shifted towards higher wave number side.

It is because there exists an interaction between the polymer and the nanomaterial molecules in

the PANI/composite. Another difference between the PANI and PANI/nanomaterial composite is

also observed, the intensity ratio is different for the benzoid and quinoid bands. In case of pure

PANI the intensity of the benzoid band is stronger as compare to quinoid band but this ratio of

the benzoid/quinoid intensity ratio is reduced considerably in composite spectra. Which reveal

that there are lesser benzenoid units in the nanocomposites compared to pure PANI and

nanomaterial promotes the stabilization of quinoid ring structure in the nanocomposites.

Fig. 2(a). FTIR spectra of PANI and PANI/nanomaterial composite of NiFe1.2Zr0.4Co0.4O4.

Fig. 2(b). FTIR spectra of PANI and PANI/nanomaterial composite of NiFeZr0.5Co0.5O4.

Fig. 2(c). FTIR spectra of PANI and PANI/nanomaterial composite of BiAl0.3Mn0.3Fe0.4O3.

3.3. XRD

Fig. 3(a) shows the XRD patterns for PANI and its composites with Zr-Co nickel ferrite. The

XRD pattern of PANI suggests that it exhibits a semi-crystalline behavior. The broad peaks at

2θ = 20.4, 25.4, and 28.2˚ are the characteristic peaks for PANI as reported earlier [1]. The

prominent peaks at 2θ = 20.4, 25.4, and 28.2˚ in XRD pattern of composite indicate the

presence of PANI and the other peaks at 2θ = 35.83, 37.20, 43.5, 50.1, 54.3, 57.2, 63.0, and

74.8˚ with miller indices 311, 222, 400, 331, 422, 511, 440, and 533, respectively, match with

standard pattern (ICDD-00-003-0875) which confirms that these peaks are related with the

substituted nickel ferrite. The presence of peaks of both materials i.e. PANI and Zr-Co-

substituted nickel ferrite confirms the formation of composite. It is found that with the

increase in concentration of NPs in composite, the intensity of NPs peaks increases while that

of PANI decreases. The crystalline size of the substituted nickel ferrite has been calculated by

using well-known Scherer’s formula which is found to be 43 nm. The values of lattice

constant and cell volume are also calculated and are found in the range of 8.363Å and 584.913

Å, respectively. The values of lattice constant and cell volume are slightly higher than that of

standard values which is due to higher atomic radii of substituents i.e. Co2+ (0.74 Å ) and Zr4+

(0.80 Å ) than that of Fe3+ (0.64 Å ).

Fig. 3(b) shows XRD patterns for PANI and PANI/NiFeZr0.5Co0.5O4 ferrite composites. The

prominent peaks at 2θ = 20.4, 25.4, and 28.2˚ in XRD pattern are related to PANI and the

other peaks are attributed to the ferrite material. The presence of peaks for both materials i.e.

PANI and Zr-Co-substituted nickel ferrite in XRD pattern confirms the formation of

composite. Increase in intensity of NPs peaks and decrease in intensity of PANI peaks with

the concentrations of NPs in composite is also observed and crystalline size of the substituted

nickel ferrite is in the range of 43 nm. The values of lattice constant and cell volume are found

in the range of 8.363Å and 584.91 Å, respectively. The values of cell volume and lattice

constant are also slightly higher. These higher values are due to larger atomic radii of

substituents i.e. Co2+ (0.74 Å) and Zr4+ (0.80 Å) than that of Fe3+ (0.64 Å).

Fig. 3(C) shows the XRD pattern of PANI, nanomaterial and PANI/ BiAl0.1Mn0.1Fe0.8O3

composite respectively which reveals that the characteristic peaks of PANI are present along

with the crystalline peaks of nanomaterial, indicating the systematic alignment of polymer

chain with the nanomaterial particles [2]. The prominent peaks at 2θ= 20.4, and 25.4° in XRD

pattern of composite confirm the presence of PANI and the extra peaks at 2θ= 11.57, 31.8,

32.7, 36.0, 40.2, 46.0, 48.7, 53.4 54.6 and 57.9° matched with standard pattern ((ICSD-01-

086-1518)) which confirm that these peaks are related to the BiAl0.3Mn0.3Fe0.4O3 substituted

ferrite. The increase in intensity of diffraction peaks of BiAl0.3Mn0.3Fe0.4O3 substituted ferrite

NPs in the PANI/nanomaterial composites spectra becomes stronger with the increase of

%age of nanoparticle, while the two original peaks of PANI show reduction in intensity at 2θ

= 20.4 and 25.40. This indicates a strong effect of the NPs on the crystallization structures of

the formed PANI/nanomaterial composites and the interaction between PANI backbone and

NPs [3]. It also indicates the increased in degree of crystalinty in PANI/nanomaterial

composite than pure PANI and homogeneous distribution of nanoparticles in the polymer

matrix. Similar results for PANI/Cds nanocomposite have also reported earlier by J. B.

Bhaiswar et al. [4]. These results confirm that nanomaterial has been successfully anchored on

the surface of PANI. The crystallite size of the AlMn- substituted ferrite has been found in the

range of 50.56 nm. Little higher values in the cell volume and lattice constant than that of the

standard values is due to higher ionic radii of substituents i.e. Mn+2 (0.80 Å) and then that of

Fe3+ (0.64 Å). The XRD studies of all these variety of composites confirmed that the

composites are successfully formed.

10 20 30 40 50 60 70 80 9010 20 30 40 50 60 70 80 90

Pure PANI

A-1

A-2

A-3

A-4

Position(20)

Inte

nsity(a

.u)

Nanomaterial

Fig. 3(a). XRD patterns for PANI and its composites (PANI) = PANI, (A-1) = 12.5%

NiFe1.2Zr0.4Co0.4O4, (A-2) = 25% NiFe1.2Zr0.4Co0.4O4, (A-3) = 37.5% NiFe1.2Zr0.4Co0.4O4, and

(A-4) = 50% NiFe1.2Zr0.4Co0.4O4.

10 20 30 40 50 60 70 80 90

Position(2O)

Pure PANI

Inte

nsity(a

.u)

C-1

C-2

C-3

C-4

Nanomaterial

Fig. 3(b). XRD patterns for PANI and its composites (PANI) = PANI, (C-1) = 12.5%

NiFeZr0.5Co0.5O4, (C-2) = 25% NiFeZr0.5Co0.5O4, (C-3) = 37.5% NiFeZr0.5Co0.5O4, and (C-

4) = 50% NiFeZr0.5Co0.5O4.

10 20 30 40 50 60 70 80 90

Pure PANI

Inte

nsity (

a.u

)

B-1

B-3

B-2

B-4

Position (20)

Nanomaterial

Fig. 3(C). XRD patterns for PANI and its composites (PANI) = PANI, (B-1) = 12.5%

BiAl0.3Mn0.3Fe0.4O3 B-2) = 25% BiAl0.3Mn0.3Fe0.4O3, (B-3) = 37.5% BiAl0.3Mn0.3Fe0.4O3, and

(B-4) = 50% BiAl0.3Mn0.3Fe0.4O3.

3.4. Scanning electron microscopy

The surface morphology and particles size was investigated by SEM analysis. Scanning

electron micrographs of pure PANI, NiFe1.2 Zr0.4Co0.4O4, and their composites are shown in

Fig. 4(a-f). SEM image of pure PANI shows the formation of smooth sheet and their surface

is plane (Fig. 4(a)). The NPs are round shaped (Fig. 4(b)) and the particle size is found in the

range of 40–50 nm. Some particles agglomerate into larger particles. From the SEM images

for the composites as shown in Fig. 4(c-f) which shows that the NPs are decorated on the

surface of PANI.

Similar results were also observed for the second series of PANI, NiFeZr0.5Co0.5O4 and PANI/

NiFeZr0.5Co0.5O4 composites and third series of PANI/multiferroics nanoparticle composite

are shown in Fig. 5(a-f) and Fig. 6(a-f) respectively. The SEM images for the second series

composites are shown in Fig. 5(c-f). These nanoparticles are round shaped (Fig. 5(b)) and the

particle size is in the range of 40–50 nm. The SEM images for the third series composites are

shown in Fig. 6(c-f) which shows that the multiferroics NPs are also round shaped (Fig. 6(b))

with particle size is in the range of 40–50 nm and multiferroics NPs decorated on the surface

of PANI, careful observation demonstrates that small sheets of PANI exist inside the surface

of the spherical core which make the composite surface highly micro-porous, it provides a

path for the insertion and extraction of ions, and increase the liquid–solid interfacial area, it

also ensures a high reaction rate [27].

The composites surfaces porosity increases with the increase of NPs concentration in composite

which is beneficial for the adsorption of both dyes and an efficient separation of photoinduced

charges is promoted by the large surface to volume ratio in nanocomposites, which is significant

characteristic of photocatalytic applications similar results were also reported by following

research groups [28-30].

Fig. 4(a). SEM images for PANI, Fig. 4(b). SEM images for Nanomaterial

Fig. 4(c). SEM images for composite(A-1), Fig. 4(d). SEM images of composites(A-2)

Fig. 4(e). SEM images of composites(A-3) Fig. 4(f). SEM images of composites(A-4)

Fig. 5(a). SEM images for PANI, Fig. 5(b). SEM images for Nanomaterial

Fig. 5(c). SEM images for composite(C-1), Fig. 5(d). SEM images of composites(C-2)

Fig. 5(e). SEM images of composites(C-3) Fig. 5(f). SEM images of composites(C-4)

Fig. 6(a). SEM images for PANI Fig. 6(b). ). SEM images for Nanomaterial

Fig. 6(c). SEM images for composite(B-1), Fig. 6(d). SEM images for composite(B-2),

Fig. 6(e). SEM images for composite(B-3), Fig. 6(f). SEM images for composite(B-4),

3.5. XPS study

The XPS analysis was carried out to determine oxidation states of the elements present in the

synthesized materials. The XPS survey for PANI and its composite with Zr-Co-substituted

nickel ferrite (50% content) is shown in Fig. 4. The XPS analysis indicates that the all the

peaks are related to the elements present in the synthesized material which confirm that there

is no other elemental impurity. The peak at 532 eV corresponds to the adsorbed oxygen [31]

while the peak at around 400 eV corresponds to N1s indicating the trivalent oxidation state of

nitrogen. The XPS spectra for Ni2p, Zr3d, Co2p, Fe2p, and C1s are shown in Fig. 7(a-e),

respectively. The Ni2p spectrum shows two peaks at around 855 and 862 eV in Fig. 7(a) that

correspond to the signals from Ni 2p3/2 and Ni2p1/2, respectively, in the divalent oxidation

state. The Zr3d spectra (Fig. 7(b)) consist of two peaks with binding energies around 182 and

184 eV which correspond to the signal from Zr3d3/2 and Zr3d5/2, respectively, which are in

the tetravalent oxidation state. The peaks appeared at 781 and 796 eV correspond to Co2p3/2

and Co2p1/2, respectively, and revealing the divalent oxidation state of cobalt (Fig. 7(c)). The

peak appears at around 711 and 725 eV (Fig. 7(d)) indicates the existence of Fe2p3/2 and

Fe2p1/2, respectively, with trivalent oxidation state. The C1s spectrum is shown in Fig. 7(e); a

peak appeared at 285 eV which correspond to the carbon in the aniline. The surface

composition of the composite has also been investigated by the XPS analysis and the results

are given in Table 1(a). It is clear from Table 1(a) that all the elements are in agreement with

the composite composition.

For second series it is observed that the peak at 532 eV corresponds to the adsorbed oxygen

[31] while the peak at around 400 eV corresponds to N1s indicating the trivalent oxidation

state of nitrogen. The XPS spectra for Ni2p, Zr3d, Co2p, Fe2p, and C1s are shown in Fig. 8(a-

e), respectively. The Ni2p spectrum shows two peaks at around 855 and 862 eV in Fig. 8(a)

that correspond to the signals from Ni 2p3/2 and Ni2p1/2, respectively, in the divalent

oxidation state. The Zr3d spectra (Fig. 8(b)) consist of two peaks with binding energies

around 182 and 184 eV which correspond to the signal from Zr3d3/2 and Zr3d5/2,

respectively, which are in the tetravalent oxidation state. The peaks appeared at 781 and 796

eV correspond to Co2p3/2 and Co2p1/2, respectively, and revealing the divalent oxidation

state of cobalt (Fig. 8(c)). The peak appears at around 711 and 725 eV (Fig. 8(d)) indicates the

existence of Fe2p3/2 and Fe2p1/2, respectively, with trivalent oxidation state. The C1s

spectrum is shown in Fig. 8(e); a peak appeared at 285 eV which correspond to the carbon in

the aniline. The surface composition of the composite has also been investigated by the XPS

analysis and the results are given in Table 1(b). It is clear from Table 1(b) that all the elements

are in agreement with the composite composition.

Table 1(a)

The amount of element (atomic%) for Zr-Co-substituted nickel ferrite/PANI composites investigated

from XPS analysis

Sr. No Element Atomic (%)

1 Zr 4.839

2 C 85.564

3 Fe 4.865

4 Co 2.098

5 Ni 2.634

Table 1(b)

The amount of element (atomic%) for Zr-Co-substituted nickel ferrite/PANI composites

investigated from XPS analysis

S. No Element Atomic (%)

1 Zr 2.187

2 C 92.381

3 Fe 2.117

4 Co 1.551

5 Ni 1.764

870 868 866 864 862 860 858 856 854 852 850

25000

26000

27000

28000

29000

30000

31000

Ni 2p1/2

Ni 2p3/2

Co

un

t/s

Binding Energy (ev)

190 188 186 184 182 180 178 176

0

500

1000

1500

2000

2500

3000

3500

zr 3d5/2

Zr 3d3/2

Co

un

ts/S

Binding Energy(ev)

Fig. 7(a). XPS spectra for Ni2p Fig. 7(b). XPS spectra for Zr3d

800 795 790 785 780 775 770

19000

20000

21000

22000

23000

24000

Co

nts

/S

Binding Energy(ev)

Co 2p1/2

Co 2p3/2

740 735 730 725 720 715 710 705 700

13000

14000

15000

16000

17000

18000

19000

20000

21000

Fe 2p1/2C

ou

nts

/S

Binding Energy(ev)

Fe 2p3/2

Fig. 7(c). XPS spectra for Co2p Fig. 7(d). XPS spectra for Fe2p

280 285 290 295 300

0

5000

10000

15000

20000

25000

30000

35000

40000

Co

nts

/S

Binding Energy(ev)

C 1s

Fig. 7(e). XPS spectra for C1s

800 600 400 200 0

0

50000

100000

150000

200000

250000

Zr 3d5/2

Zr 3s

Zr 4pZr 2d3/2

N 1s

O 1s

Fe 2p3/2

Co 2p1/2

Ni 2p3/2

Count/S

Binding energy(ev)

Ni 2p1/2

C 1s

Fig. 7(f). XPS survey for PANI composite with 50% NiFe1.2Zr0.4Co0.4O4.

280 285 290 295 300

0

5000

10000

15000

20000

25000

30000

35000

40000

Co

nts

/S

Binding Energy(ev)

C 1s

740 735 730 725 720 715 710 705 700

13000

14000

15000

16000

17000

18000

19000

20000

21000Fe 2p3/2

Fe 2p1/2

Co

un

ts/S

Binding Energy(ev)

Fig. 8(a). XPS spectra for Ni2p Fig. 8(b). XPS spectra for Zr3d

800 795 790 785 780 775 770

19500

20000

20500

21000

21500

22000

22500

23000

23500

24000Co 2p3/2

Co

un

ts/S

Binding Energy(ev)

Co 2p1/2

Fig. 8(c). XPS spectra for Co2p Fig. 8(d). XPS spectra for Fe2p

870 868 866 864 862 860 858 856 854 852 850

24000

25000

26000

27000

28000

29000

30000

31000

Ni 2p3/2

Ni 2p1/2

Co

un

ts/S

Binding Energy(ev)

740 735 730 725 720 715 710 705 700

13000

14000

15000

16000

17000

18000

19000

20000

21000Fe 2p3/2

Fe 2p1/2

Co

un

ts/S

Binding Energy(ev)

Fig. 8(e). XPS spectra for C1s

800 600 400 200 0

0

50000

100000

150000

200000

250000

300000

350000

Fe 2p1/2

Zr4p

Zr 3d3/2

Zr 3d5/2

Zr 3s

N 1s

O 1s

Fe 2p3/2

C 1s

Ni 2p3/2

Ni 2p1/2

Co 2p3/2

Counts

/s

Binding energy (ev)

Fig. 8(f). XPS survey for PANI composite with 50% NiFeZr0.5Co0.5O4.

3.6. BET Studies

The BET study has been used to investigate the surface area and pores volume for the PANI and

the substituted nickel ferrite/PANI composites. The values of parameters such as BET and

Langmuir surface area and pore volume are shown in Table. 2(a), 2(b), and 2(c) for all three

series respectively. It is clear from the table that the surface area and pore volume increase with

the increase in substituted ferrite content for all the composites materials. The increase in surface

area and pore volume suggests that it increases the adsorption sites which make the composite

materials more beneficial for the photodegradation as compared to individual catalyst.

Table 2(a)

BET and Langmuir Surface area and maximum pore size of substituted PANI and nickel

ferrite/PANI composites

Samples BET surface area

(m2/g)

Langmuir surface area

(m2/g)

Maximum pore

volume (cm3/g)

PANI 6.8971 11.2720 0.002854

A-1 14.2641 37.3429 0.004377

A-2 34.2377 53.8788 0.004871

A-3 40.928 74.0171 0.004900

A-4 53.4599 91.9178 0.005172

Table 2(b)

BET and Langmuir Surface area and maximum pore size of substituted PANI and nickel

ferrite/PANI composite

Sample BET surface area

(m2/g)

Langmuir surface

area (m2/g)

Maximum pore

volume (cm3/g)

PANI 6.8971 11.2720 0.002854

C-1 14.361 37.7342 0.004537

C-2 35.0207 53.9889 0.004987

C-3 41.281 74.37119 0.004901

C-4 53.7419 92.1918 0.005187

Table 2(c)

BET and Langmuir Surface area and maximum pore size of substituted PANI and Al-Mn

multiferroics/PANI composites

Samples BET surface area

(m2/g)

Langmuir surface area

(m2/g)

Maximum pore

volume (cm3/g)

PANI 6.8971 11.2720 0.002854

B-1 16.2641 37.3429 0.004377

B-2 38.2377 53.8788 0.004871

B-3 51.2113 68.002 0.004971

B-4 65.4599 91.9178 0.005172

3.7. Degradation of dyes

3.7.1. Influence of reaction time.

Residence time in light is one of the most important parameter that affects the photodegradation

of dyes. The relationship between degradation and reaction time is shown in Fig. 9(a-f) for

methylene blue and methylene orange respectively. It is clear from figure that the degradation of

dyes increases with the increase in reaction time. It was also observed that the degradation was

very rapid during the initial stage of the reaction and after 30 min it began to slow down. The

ultimate degradation was found beyond 98% and 97% for MO and MB respectively during the

investigated reaction time of 150 min. When PANI and its composites were illuminated with UV

light, it absorbs photons to generate electron– hole pairs and these electrons and holes generate

the hydroxyl radicals (OH⦁) by reacting with water molecules. Hydroxyl radicals (OH⦁) are the

most important species in photodegradation reaction therefore the rate of degradation is directly

related to the formation or OH⦁ radicals. One more thing which play a significant role in the

photodegradation reaction i.e. the rate of reaction of OH⦁ radicals with reactant followed by the

equilibrium adsorption of that reactant on the surface of the catalyst [44]. The surface of

PANI/NPs composite is porous as shown in SEM image, its surface area as well as the pore size

is greater as confirm by BET analysis (Table. 2(a-c)). These pores act as active sites to adsorb

the MB molecule. These adsorbed molecules of MB & MO could easily captured by

photogenerated oxidizing species OH⦁ and degraded immediately, resulting a rapid degradation

of MB in first 30 min. As the time precede, availability of these active sites decreased and also

oxidizing species (OH⦁) which results in decrease in rate of degradation of MB. For the second

series relationship between degradation and reaction time is shown in Fig. 9(c-d) for methylene



blue and methylene orange, respectively. The total degradation was 98 % and 94.5 % for MO

and MB respectively during the 150 min of investigated reaction time. And for the third series of

photocatalyst the relationship between degradation and reaction time is shown in Figure 9(e-f)

for both dyes i.e. methylene blue and methylene orange respectively. The ultimate degradation

was found beyond 98 % and 93.5 % during the investigated reaction time of 150 min for

methylene blue and methylene orange respectively. It was found that the rate of degradation

increases with the increase of time. The rate of degradation was fast during the initial stage of

reaction .i.e. 30 minutes but after 30 min it began to slow down for both second and third series.

The generation of OH⦁ radicals is crucial in photodegradation process as it oxidizes the dyes

molecules to carbon dioxide and water.

The degradation goes to maximum till 30 minutes this is due to the availability of O2 and initially

more OH⦁ radicals generated rapidly. In the initial 30 minutes there will be large number of

photons reaching the catalyst surface and lot of O2 is available therefore, more OH⦁ radicals

will be formed, subsequently the relative number of OH⦁ radicals that attack the compound also

high and rate of degradation of dyes will be maximum. One more reason is also there the rapid

initial rate of degradation in the first 30 minutes, the pores at the surface of PANI/NPs composite

as shown in SEM image and BET analysis (Table. 2(a-c)) act as active sites to adsorb the dyes

molecule. These adsorbed molecules captured by photogenerated oxidizing species OH⦁ and

degraded immediately; it shows rapid degradation of both dyes in first 30 min. As the time

precede, availability of these active sites decreased and oxidizing species (OH⦁) also decreases

which results in decrease in rate of degradation. It was reported by [45] that rate of degradation

relates to the OH⦁ radical formation and the equilibrium of the adsorption of reactants on the

catalyst surface with the rate of reaction of OH⦁ radicals with other chemicals. Therefore with



the increase of time availability of the active sites decreases and degradation is also decreases

The rate of degradation of MO is little high compare to MB .It is due to the fact that

photodegradation of anionic dyes is promoted by adsorption because the negatively charged

groups of these dyes experience chemical interactions with the positively charged backbone of

polyaniline (PANI) as suggested by Xi. et.al. [46]. Methylene blue is a cationic dye [47] the

cationic dyes containing positively charged groups and due to electrostatic repulsion they cannot

easily gain contact to the positively charged backbone of PANI, giving low photodegradation

rates [46]

Table 3(a)

MO %age Degradation with time.

TIME PANI A-1 A-2 A-3 A-4 Nano

0 0 0 0 0 0 0

30 25 50.5 53 64 66 29

60 32 65 66.4 73 77 35

90 38 76 79.6 86.2 92 37

120 43 84 89 92 96 39

150 45 88 91 95 98 39

Table 3(b)

MB % degradation with time.

TIME Pure PANI A-1 A-2 A-3 A-4 Nano

0 0 0 0 0 0 0

30 20 33.1 54.96 68.82 76.16 32

60 27 52.58 64.13 74.27 81.2 35

90 40 62.89 72.42 81.01 87.2 42

120 45 74.21 78.18 87.1 92.26 46

150 48 78.58 84.4 92.68 97.12 46

Table 3(c)

MO %age Degradation with time

TIME PANI C-1 C-2 C-3 C-4 Nano

0 0 0 0 0 0 0

30 25 47 51 58 62 25

60 32 61 64 73 78 32

90 38 73 78 86 92 37

120 43 82 86 92 96 37

150 45 87 90 94 98 40

Table 3(d)

MB % degradation with time.

TIME Pure

PANI

C-1 C-2 C-3 C-4 Nano

0 0 0 0 0 0 0

30 20 55 59 65 78 30

60 27 65 72 74 85 34

90 40 77 82 83 91 39

120 45 84 88 89.5 93 40

150 48 89 91.5 94 94 42

Table 3(e)

MO %age Degradation with time

TIME PANI B-1 B-2 B-3 B-4 Nano

0 0 0 0 0 0 0

30 25 50.5 53 64 66 28

60 32 65 66.4 73 77 32.5

90 38 76 79.6 86.2 92 35.6

120 43 84 89 91 95 37

150 45 89 91 96 98 39

Table 3(f)

MB % degradation with time

TIME Pure

PANI

B-1 B-2 B-3 B-4 Nano

0 0 0 0 0 0 0

30 20 55 59 65 78 30

60 27 65 72 74 85 34

90 40 77 82 83 90 39

120 45 84 88 87.5 92 40

150 48 89 91.5 91 93.5 42

0 20 40 60 80 100 120 140 160

0

10

20

30

40

50

60

70

80

90

100

% D

eg

rad

atio

n

Time(min)

NPs

PANI

A-4A-3A-2A-1

Fig. 9(a). Influence of time on the photodegradation of MO

0 20 40 60 80 100 120 140 160

0

10

20

30

40

50

60

70

80

90

100

% D

eg

rad

atio

n

Time(min)

A-1

A-2

A-3

A-4

PANINPs

Fig. 9(b). Influence of time on the photodegradation of MB

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

90

100

C-3C-2

% D

egra

dation

Time(min)

Nano Material

PANI

C-1

C-4

Fig. 9(c). Influence of time on the photodegradation of MO

0 20 40 60 80 100 120 140 160

0

10

20

30

40

50

60

70

80

90

% D

egra

dation

Time(min)

Nano

PANI

C-1

C-2C-3C-4

Fig. 9(d). Influence of time on the photodegradation of MB

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

90

100

% D

egra

datio

n

Time(min)

Nano

PANI

B-1B-2B-3B-4

Fig. 9(e). Influence of time on the photodegradation of MO

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

90

100

% D

egra

datio

n

Time(min)

Nano

PANI

B-1B-2B-3B-4

Fig. 9(f). Influence of time on the photodegradation of MB

3.7.2. Effect of nanomaterial (%) age in composite

The effect of Zr-Co-substituted nickel ferrite NPs concentration into the composite was also

examined. The increase in Nps concentration from 12.5%, 25%, 37.5% to 50% wt. in composite

increases the degradation rate. It is important to mention that bubbles were observed during the

experiments. These bubbles are expected because of O2 produced from photolysis by composite

and CO2 produced from complete degradation of dye. The generation of bubbles increased with

an increase of the Nps (%) age in composite. The increase in the rate of degradation is due to the

fact that as the ferrite content increase in the composite, the surface area as well as the pore

volume increase (Table. 1(a-c)). Both these factors are responsible for the rise in the

photodegradation rate of dye. In photodegradation reaction, excited electron from valence band

move to the conduction band and leaving holes, these holes created by the movement of

electrons, react with water molecules to generate OH●. With the increase in NPs (%) age in

composite, the light penetration through on the photocatalyst surface also increased and more

OH● was generated. The SEM images and BET analysis reveal that the surface of the catalyst

becomes more porous which increase the adsorption of dye and as a result the degradation

increases. The maximum photodegradation was observed in case of 50% content of

nanomaterials into the composite. The percentage degradation of MB and MO is 97% and 98

respectively, for the composite having 50% nickel ferrite content is compared with the other

photocatalysts reported in literature. The effect of catalyst dosage of second and third series on

the photocatalyst activity was also studied. The varied amount of nanomaterial in the composite

at the range of 0 to 50% for 40 mL of 0.1M×10-5 MB and 0.1M×10-5 MO solution was used to

determine the rate of photodegradation reaction for both series. At the higher %age of

nanomaterial in composite increase the adsorbent surface area within the range of 12.5 to 50%

wt. of composite per 40 mL of MB solution. The percentage degradation of MB and MO is found

to be 94.5 % and 98 % respectively for the second series and 99 % to 97 % of MB and MO

respectively for the third series. High specific surface areas with porous structures provide more

active sites and adsorb more reactive species therefore the photocatalysts having these

characteristics are confidently recommended and are widely accepted to be beneficial for the

enhancement of photocatalytic performance [48]. It is also reported that degradation is related

to the formation of OH⦁ radical and the equilibrium, between the adsorption of reactants on the

catalyst surface and the rate of reaction of OH⦁ radicals [44]. The surface of the catalyst is

pours and this porosity is maximum at 50 % content of nanomaterial as indicated by SEM

images and BET analysis. Pores not only increases the surfaces area but also increase the

adsorption of dyes molecules on the surface of the catalyst as result the degradation increases

with the increase of nanomaterials % age in the photocatalyst. However, the activities of PANI

and pure nanomaterial were lowered as compared to PANI/Nanomaterial composite. For pure

nanomaterial decrease in degradation is because of the, amount of dyes molecules is no longer

sufficient to accept all photo-activated electron from nanomaterial molecules on time. Therefore

numbers of electron-hole pairs generated by irradiation of UV light are quickly recombined and

therefore result in reduced photocatalytic degradation of MB [49]. The percentage degradation

of MB and MO which is 99% for the composite having 50% substituted ferrite content is

compared with the other photocatalysts reported in literature.



3.7.3. Kinetic study

Experimental results showing degradation of MB in UV irradiated by PANI/nanomaterial

composite suspensions indicated that more than 95% of MB is degraded within 1 h under the

conditions shown. In comparison, no significant loss of MB occurs in PANI/nanomaterial

composite suspensions maintained under darkness only a small fraction (<10%) of the

compound is degraded by UV irradiation in the absence of PANI/nanomaterial composite.

Degradation of MB during batch reactions was described using a pseudo first-order kinetic rate

law. It was found that decrease in dye concentration take places linearly with of irradiation time.

It suggests that the pseudo first-order kinetics mechanism operates for degradation of dyes.

Langmuir-Hinshelwood (L-H) model depend upon the surface-area; therefore with irradiation

time reaction rate is expected to increase but as the time precedes decrease in organic substrate

take place and surface area also decreased after increased irradiation times. It is assume to be

zero rate of degradation if total decomposition is achieved. For the applicability in the area of

photo- mineralization many assumptions for the L-H saturation kinetics form may occurs, there

are four possible situations and any one of these may valid:

1) There are two adsorbed components and reactions take place between these two components

of radicals and organics;

2) The reactions are between the adsorbed organics and radicals in water;

3) It is also possible that reactions between the radical on the surface and organics in water take

places;

4) Reaction takes place between with both the radical and organics in water.

Some researchers [50-51] suggested that only zero or first-order kinetics is enough to explain

the photo mineralization of organic compounds. It is possible but there are some conditions

exist, for example, where the solute concentration is insufficiently low.

In several kinetic studies a plateau-type of kinetic profile is observed in the cases where the

oxidation rate increases with irradiation time until the rate becomes zero [50]. Photocatalytic

degradation kinetics data was fitted to first- and second-order kinetic model to investigate the

mechanism for the degradation of MB.

The first-order equation is given as:

log(qe − qt) = logqe −k1

2.303t

(3)

Where qe and qt are amount of MB degrade at equilibrium and time “t”, respectively, and k1 is

the specific rate constant for first order reaction [52]. A plot of log (qe – qt) vs. t for first-order

kinetic is shown in Fig. 10(a-f). The value of specific rate constant increases from 9.6 × 10−3

to 17 × 10−3 s−1 (shown in Tables 4(a-f)) with the increase of NPs (%) age which is due to

increase in the porosity of the surface and surface area of material (as indicated by SEM and

BET results) which act as active sites and increase the adsorption of MB. As a result, the

degradation as well as the specific rate constant increased. The linear regression correlation

coefficients (R2) varied in the range of 0.9358–0.9947. The second-order equation is given as:

t

qt=

1

k2qe2

−1

qet

(4)

The graph has been plotted between t/qt vs. t (shown in Fig. 11(a-f)) and the value of qe and k2

are calculated from the slope and intercept, respectively and their values are given in Tables

4(a-f). Linear regression correlation coefficients (R2) value calculated from plot of t/qt vs. t for

second-order kinetic model that ranges from 0.7396 to 0.9556 indicate that experimental data

does not obey second-order kinetic model. From above discussion, it can be suggested that

rate of degradation of MB follows first-order kinetic. The rate of degradation of MB increases

with the increase of NPs (%) age in PANI/NPs composite as shown in Table 4 as indicated by

value of first-order specific rate constant. The controlling factor of this oxidation reaction is

the concentration of NPs which produce OH radical during course of reaction. The proposed

mechanism is:

PANI/NPs Composite + hv → ecb + hvvb

+ (5)

hvvb+ + OH → O· H (6)

H+ + ecb → H· (7)

O2 + ecb → O2

· H·

→ HO2

(8)

HO2 + hvvb

+ → HO2· (9)

Dye + O· H → Degradation Product (10)

From the irradiation of UV-light, PANI/NPs composite involved in oxidation-reduction

process becomes excited. The surface of the PANI/NPs composite becomes activate and

excited electron moves from valence band to the conduction band and leaving hole. This

electron and hole reacts separately with water molecules to generateOH∙. On the other side

OH and H+ which are involved in the photodegradation reaction traps hvvb+ and ecb

and make

them available for the reactions taking place at the surface of PANI/NPs and prevent the

recombination of ecb and hvvb

+ . Hydroxyl radicals attack is assumed to be the primary

mechanism for photo oxidation as suggested by Turchi and Ollis [53]. And holes are likely to

react with OH because it is readily absorbed to the catalyst surface. By summing it up, in

degradation process, light energy was adequately absorbed by NPs present in PANI/NPs

composite; therefore, composite having high percentage of NPs produces large amount of OH∙

radical groups rapidly and oxidation reaction proceed very quickly.

Experimental results for the photocatalytic degradation for second and third series shows that

more than 94.5 % of MB and 98 % of MO for second series and 98 % for third series degraded

within 150 minutes. There is no significant loss of both dyes occurs in PANI/nanomaterial

composite suspensions when maintained under darkness or dyes solution alone under the UV

irradiation in the absence of PANI/nanomaterial composite but a small fractions (<10%) of the

dyes is degraded. Degradation of both dyes by photocatalyst under the UV light during batch

reactions was described using a pseudo-first-order kinetic rate law:

It was observed that decreasing dyes concentrations is linearly related to the elapse of irradiation

time. This means that the pseudo first-order kinetics mechanism operates for degradation of both

dyes fro second and third series.

The value of specific rate constant increases from 13.5 × 10−3 to 26 × 10−3 s−1 for MO and 14.5 ×

10−3 to 19.2 × 10−3 s−1 for MB (shown in Tables 4(c-d)) for the second series photocatalyst and

13.8 × 10−3 to 19.1 × 10−3 s−1 for MO and 12.5 × 10−3 to 17.2 × 10−3 s−1 for MB (shown in Tables

4(e-f) for the third series photocatalyst which increase with the increase of NPs (%) age. It is due

to increase in the porosity of the surface and surface area of material (as indicated by SEM and

BET results) which act as active sites and increase the adsorption of dyes. As a result, the

degradation as well as the specific rate constant increased. The linear regression correlation

coefficients (R2) varied in the range of 0.990–0.995 for MO and 0.990 to 0.996 for MB for

second series photocatalyst and 0.980–0.995 for MO and 0.985 to 0.99 for MB for third series

photocatalyst.

The slope and intercept values for both photocatalyst series are given in Table 5(a-f). Linear

regression correlation coefficients (R2) value calculated from plot of t/qt vs. t for second-order

kinetic model that ranges from 0.742 to 0.858 for MO and 0.832 to 0.834 for MB of second

series while 0.75 to 0.88 for MO and 0.82 to 0.83 for MB of third series, indicate that

experimental data does not obey second-order kinetic model but it follows first-order kinetic for

both dyes.

Table. 4(a)

First-order specific rate constant for k1, second-order specific rate constant k2, and correlation

coefficient R2

MO First order MO Second order

k1 (sec−1) R² k2 (L−1 mol sec−1) R²

PANI 0.0037 0.8963 0.0184 0.9924

A-1 0.0137 0.9805 0.0812 0.8898

A-2 0.0161 0.9815 0.1112 0.8755

A-3 0.0192 0.981 0.1874 0.8176

A-4 0.0257 0.9907 0.4486 0.7423

Nano 0.0028 0.6917 0.0164 0.998

Table. 4(b)


coefficient R2

MB First order MB Second order


PANI 0.0077 0.9815 0.0605 0.8677

A-1 0.0096 0.9914 0.3799 0.7396

A-2 0.0087 0.9947 0.055 0.9556

A-3 0.0120 0.9626 0.0726 0.9293

A-4 0.0170 0.9358 0.1535 0.8508

Nano 0.1594 0.6917 0.0993 0.9947

Table 4(c)


coefficient R2



PANI 0.0037 0.896 0.0184 0.992

C-1 0.0135 0.990 0.0787 0.858

C-2 0.015 0.988 0.0965 0.867

C-3 0.0196 0.991 0.1877 0.816

C-4 0.026 0.995 0.4487 0.742

Nano 0.0029 0.776 0.0167 0.997

Table 4(d)


coefficient R2


k2 (L−1 mol sec−1) R² k1 (sec−1) R²

PANI 0.0195 0.962 0.0044 0.985

C-1 0.0842 0.996 0.0142 0.832

C-2 0.0987 0.990 0.0155 0.881

C-3 0.1546 0.995 0.0185 0.803

C-4 0.1744 0.990 0.0192 0.834

Nano 0.0173 0.749 0.0031 0.997

Table. 4(e)


coefficient R2



PANI 0.0037x + 0.1063 0.8963 0.0184x - 0.119 0.9924

B-1 0.0138x + 0.1019 0.9924 0.0812x - 1.7419 0.8898

B-2 0.0146x + 0.1093 0.9905 0.1112x - 2.6056 0.8755

B-3 0.0173x + 0.105 0.9945 0.1874x - 4.9609 0.8176

B-4 0.0191x + 0.1496 0.9903 0.4486x - 13.686 0.7423

Nano 0.0027x + 0.2284 0.5051 0.0164x - 0.0556 0.998

Table 4(f)


coefficient R2



PANI 0.0037x + 0.1063 0.8963 0.0195x - 0.1719 0.9859

B-1 0.0138x + 0.1019 0.9924 0.0801x - 1.7905 0.8756

B-2 0.0146x + 0.1093 0.9905 0.0884x - 1.9889 0.8817

B-3 0.0173x + 0.105 0.9945 0.1341x - 3.4511 0.8258

B-4 0.0191x + 0.1496 0.9903 0.182x - 4.9853 0.7851

Nano 0.0027x + 0.2284 0.5051 0.017x - 0.0134 0.9999

0 30 60 90 120 150

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

ln(q

t/qo)

Time(min)

A-4

A-3

A-2

A-1

PANI

NPs

Fig. 10(a). First-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

t/q

t

Time(min)

A-4

A-3

A-2

A-1

PANINPs

Fig. 11(a). Second-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

ln(q

t/qo)

Time(min)

A-4

A-3

A-2

A-1

PANI

NPs

Fig. 10(b). First-order kinetic plot for the photodegradation of MB.

0 30 60 90 120 150

0

10

20

30

40

50

t/q

t

Time(min)

A-4

A-3

A-2A-1PANINPs

Fig. 11(b). Second-order kinetic plot for the photodegradation of MB.

0 30 60 90 120 150

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

ln(q

t/qo)

Time(min)

C-4

C-3

C-2

C-1

PANINano

Fig. 10(c). First-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

t/q

t

Time(min)

C-4

C-3

C-2C-1

PANI

Nano

Fig. 11(c). Second-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

0.0

0.5

1.0

1.5

2.0

2.5

3.0

ln(q

t/qo)

Time(min)

C-4

C-3

C-2

C-1

PANI

Nano

Fig. 10(d). First-order kinetic plot for the photodegradation of MB.

0 30 60 90 120 150

0

10

20

30

40

50

60

70

80

t/q

t

Time(min)

C-4

C-3

C-2C-1

PANI

Nano

Fig. 11(d). Second-order kinetic plot for the photodegradation of MB.

0 30 60 90 120 150 180

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

ln(q

t/qo)

Time(min)

B-4

B-3

B-2

B-1

PANINanomaterial

Fig. 10(e). First-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

0

20

40

60

80

t/q

t

Time(min)

B-4

B-3

B-2

B-1

PANINanomaterial

Fig. 11(e). Second-order kinetic plot for the photodegradation of MO

0 30 60 90 120 150

0.0

0.5

1.0

1.5

2.0

2.5

3.0

ln(q

t/qo)

Time(min)

B-4

B-3

B-2

B-1

PANI

Nanomaterial

Fig. 10(f). First-order kinetic plot for the photodegradation of MB.

0 30 60 90 120 150

0

5

10

15

20

25

30

35

t/q

t

Time(min)

B-4

B-3

B-2

B-1

PANI

Nanomaterial

Fig. 11(f). Second-order kinetic plot for the photodegradation of MB.

Conclusion

The two series of PANI/Zr-Co-substituted nickel ferrite composite and a MnAl-substituted

multiferroics was synthesized by adding nanomaterials during polymerization reaction of aniline

chloride by ammonium peroxydisulphate.

The XRD confirmed the formation of PANI/NPs composites. The composites contain the

peaks for the both materials which confirmed that the composite has been prepared

successfully of all three series.

UV-Vis studies reveal the interaction between dopant metal complex and the polyaniline

backbone chains. It is concluded by observing the increase in intensity of π–π* transition

peak and excitonic transition peak as compared to that of pure PANI.

The XPS studies confirmed the oxidation state of different elements in the composite and

NPs.

The FTIR Study also confirms the formation of composites and shifting of peaks towards

higher wave number side which are due to interaction between the polymer and the

nanomaterial molecules in the PANI/composite.

SEM images indicate that nanoparticles decorate the surface of PANI which is in the

form of sheets and increase the porosity on the surface of PANI which act as active sites

for the adsorption and degradation of MB and MO for all three NPs composites.

The BET analysis confirmed that the surface area increases with the increase in ferrite

content in the composite which increases the adsorption sites and make the composite

materials more beneficial for the photodegradation as compared to individual catalyst.

The kinetics studies showed that the degradation process follow the first-order kinetic model.

The photodegradation of MB as well as MO increases with the increase in nanoparticle content

in the composite and maximum for the sample with 50% ferrite nanoparticle composite which is

much higher as compared to other photocatalyst reported in the literature. The high degradation

percentage by present composite indicates that these can be used as photocatalyst for the removal

of MB and MO from water.

Documents

Doctor of Philosophy In Physical Chemistry By Muhammad Aamir