Synthesis of NiO Nanoparticles from Industrial Waste

8/19/2019 Synthesis of NiO Nanoparticles from Industrial Waste

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CHAPTER 1

INTRODUCTION

The electroplating or metal finishing industry has been playing a momentous role inthe development and growth of numerous metal manufacturing and other engineering

industries since the early part of this century. While electroplating operations have, in

the course of time, become an essential and integral part of many engineering

industries throughout the world, there has also been a steady growth of independent

and small to medium scale electroplating industries, especially in the developing

countries including, India.

Electroplating is the electro deposition on metals, alloys

and non-metallic. The electroplating of common metals includes the processes inwhich ferrous or non-ferrous base materials is electroplated with nickel, chromium,

copper, zinc, lead, iron, cadmium, aluminum, brass, bronze etc. One of the major

chemical waste producing industries is the electroplating industry generating a

whooping amount of waste which comprises of Nickel, Cadmium, Chromium,

Palladium and several other carcinogenic elements. This waste gets in to the water

cycle and in turn accounts for several diseases in our ecosystem.

1.1 Literature Survey

According to a report about 700,000 electroplating units were working in India, out of

which about 5000 units are in Aligarh. The wastewater generated in Aligarh by lock

industries, specially electroplating industries is around 250 million litres per day.

From all these units a very harmful waste containing carcinogenic elements was found

to be disposed heedlessly in water bodies.

After accessing all these information we came to a conclusion that there is animmediate need to pacify the adverse impact of these wastes and nevertheless

harnessing the metallic content of these in some lucrative way. With the growth of

industry, environmental pollution is rapidly increasing in our country. The awareness

of environmental pollution control has come much later than the development of

chemical industry in India. The legislation has also come much later than the

industrial growth.


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The successful recovery of this high waste content with development of cleaner

production processes has resulted in huge savings in water, chemicals, degreasing

substances etc. Thus recycling can help in recovery as well as providing better

surroundings. Apart from the above mentioned advantages, some others are:-

1) Recycling of rinse water and effluent helps in reducing the consumption of costly

bath solution thus reducing the cost of operation.

2) Reduction in the problems and costs associated with the treatment and disposal of

waste.

3) To provide least amount of contaminants and toxic materials so as not to pollute

the environment for better surroundings.

In India though due to lack of awareness and economic reasons these recovery

processes have not been resorted to mainly by the industries in the small scale sector.

Studies are currently in progress to properly define the plating waste market character,

pin point potential clients, and obtain more detailed data on waste volumes,

composition and variability.

Table 1.1 Heavy Metal Concentration in electroplating waste.

As the table 1.1 suggests that in these wastes, Nickel element is present as a potential

waste. Owing to the characteristics of an element at nano level we inferred that

Metals Concentration (inppm or mg/L )

Nickel 139

Zinc 27

chromium 17

Cadmium 5

Lead 3

Copper 1


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synthesising nickel nano particles from waste could pave a way ahead towards a

greener environment.

1.2 Electroplating industry

Electroplating is one of the varieties of several techniques of metal finishing. It is a

technique of deposition of a fine layer of one metal on another through electrolytic

process to impart various properties and attributes, such as corrosion protection,

enhanced surface hardness, lustre, colour, aesthetics, value addition etc. Electroplating

process has applications in large scale manufacturing plants (e.g. automobile, cycle,

engineering and numerous other industries) as well as job-work by small and tiny

units. Though this process has a long history, but it gained momentum after

independence. In 1976, the first semi-automatic plant was set up in Mumbai.

Currently there are more than 600 automatic plants in the county. It is estimated that

electroplating is now worth Rs. 1000 crores and this sector employs 1, 30,000

approximately people in the industry in 12000 organized sectors. However, hardly

any data is available for unorganized sectors and it is difficult to find the distribution

of production in unorganized.

Fig 1.1: An Electroplating unit working in Aligarh.


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The current technology options for recovery which is one of main objectives are given

in brief below:

1) Electro chemical treatment process- This process has been developed to recover

metal from dilute electroplating and rinse water solution. Some of the advantagesare low operating costs that can be applied to all platable materials.

2) By Micro filtration, heavy metals like Nickel, Chromium, Gold, Silver and Copper

can be recovered. The disadvantage of this process is, a filter cake is produced

which is a hazardous waste and thus it is not recommended.

3) Chemelec Cell is one of recommended technologies that has been installed in manyindustries abroad giving profitable results. It is an electrolytic recovery process and

is used to recover different precious metals like nickel, cadmium, zinc etc.Chromium is a metal which cannot be recovered by this process.

1.3 Rationale of study

On one hand, the process has number of applications but, simultaneously it has been

included among 17 major polluting industries in India by Central Pollution and

Control Board, government of India. Electroplating is considered a major polluting

industry because it discharges toxic materials and heavy metals through wastewater(effluents), air emissions and solid wastes in environment. It was found that a large

amount of metals and chemicals is disposed into main stream without treatment as

they have no effective measures for treatment or recovery of metals in unorganized

sectors. At the same time it is to be kept in mind that majority of units are in tiny and

small scale, which are not able to upgrade the technology immediately to achieve

cleaner production. Thus, it is not possible to protect the environment in a significant

manner, unless cleaner production is achieved. Consequently, there is a need to adopta balanced and practical approach so that goal is achieved over a period of time.

Adoption of proper handling and recycling methods will help in the optimization of

the use of various raw materials. The recovered materials can be used again, thus

reducing their consumption in these industries. The recovered materials can also be

used by other industries for their raw materials.

The precious materials, of which most of the requirements are met through imports,

after recovery lead to reduced exploitation of these materials and also reduces the


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burden on imports. The cost benefits due to implementation of pollution control

measures may be long term but they yield better productivity.

1.4 Objective of Our Study

For this project report we met the following objectives:

i) Preliminary study carried put to confirm the abundance of Nickel in the

waste.

ii) Collection of detailed information on materials used in electroplating (like

Nickel, Chromium, Silver etc.)

iii) Different solvent for synthesis and preparation of nano materials.

iv) Characterisation techniques performed to reveal the properties ofsynthesised product.


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CHAPTER 2

NANOTECHNOLOGY: PRINCIPLES AND APPLICATIONS

The term nanotechnology comes from the combination of two words: the Greek

numerical prefix nano referring to a billionth and the word technology. As an

outcome, Nanotechnology or Nano scaled Technology is generally considered to be at

a size below 0.1 µm or 100 nm (a manometer is one billionth of a meter, 10-9 m).

Nano scale science (or Nano science) studies the phenomena, properties, and

responses of materials at atomic, molecular, and macromolecular scales, and in

general at sizes between 1 and 100 nm. In this scale, and especially below 5 nm, the

properties of matter differ significantly (i.e., quantum-scale effects play an important

role) from that at a larger particulate scale. Nanotechnology is then the design, the

manipulation, the building, the production and application, by controlling the shape

and size, the properties-responses and functionality of structures, and devices and

systems of the order or less than 100 nm.

Nanotechnology is considered an emerging technology due to the possibility to

advance well-established products and to create new products with totally new

characteristics and functions with enormous potential in a wide range of applications.

In addition to various industrial uses, great innovations are foreseen in informationand communication technology, in biology and biotechnology, in medicine and

medical technology, in metrology, etc. Significant applications of Nano sciences and

Nano engineering lie in the fields of pharmaceutics, cosmetics, processed food,

chemical engineering, high-performance materials, electronics, precision mechanics,

optics, energy production, and environmental sciences.

Nanotechnology is one of the leading scientific fields today since it combines

knowledge from the fields of Physics, Chemistry, Biology, Medicine, Informatics,and Engineering. It is an emerging technological field with great potential to lead in

great breakthroughs that can be applied in real life. Novel nano and biomaterials, and

nano devices are fabricated and controlled by nanotechnology tools and techniques,

which investigate and tune the properties, responses, and functions of living and non-

living matter, at sizes below100 nm. The application and use of nano materials in

electronic and mechanical devices, in optical and magnetic components, quantum

computing, tissue engineering,


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Fig. 2.1: Nanoscale size comparision

and other biotechnologies, with smallest features, widths well below 100 nm, are the

economically most important parts of the nanotechnology nowadays and presumably

in the near future. The number of nano products is rapidly growing since more and

more

nano engineered materials are reaching the global market The continuous revolution

in nanotechnology will result in the fabrication of nanomaterials with properties and

functionalities which are going to have positive changes in our lives, be it in health,

environment, electronics or any other field. In the energy generation challenge wherethe conventional fuel resources cannot remain the dominant energy source, taking into

account the increasing consumption demand and the CO2emissions alternative

renewable energy sources based on new technologies have to be promoted. Innovative

solar cell technologies that utilize nano structured materials and composite systems

such as organic photovoltaics offer great technological potential due to their attractive

properties such as the potential of large-scale and low-cost roll-to-roll manufacturing

processes The advances in nanomaterials necessitate parallel progress of thenanometrology tools and techniques to characterize and manipulate nanostructures.


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Nanotechnology can help in solving serious humanity problems such as energy

adequacy, climate change or fatal diseases. Nanosciences and nanotechnologies open

up new avenues of research and lead to new, useful, and sometimes unexpected

applications. Novel materials and new-engineered surfaces allow making products

that perform better. New medical treatments are emerging for fatal diseases, such as

brain tumours and Alzheimer‘s disease. Computers are built with nanoscale

components and improving their performance depends upon shrinking these

dimensions yet further.

Nanomaterials with unique properties such as: nanoparticles carbon nanotubes,

fullerenes, quantum dots, quantum wires, nanofibers, and nanocomposites allow

completely new applications to be found. Products containing engineered nano

materials are already in the market. The range of commercial products available today

is very broad, including metals, ceramics, polymers, smart textiles, cosmetics,

sunscreens, electronics, paints and varnishes.

Nanomaterials must be examined for potential effects on health as a matter of

Fig. 2.2: Diverse application of nanotechnology


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precaution, and their possible environmental impacts. However new methodologies

and instrumentation have to be developed in order to increase our knowledge and

information on their properties.

The development of specific guidance documents at a global level for the safety

evaluation of nanotechnology products is strongly recommended. Ethical and moral

concerns also need to be addressed in parallel with the new developments.

Huge aspirations are coupled to nano technological developments in modern

medicine. The potential medical applications are predominantly in diagnostics(disease

diagnosis and imaging), monitoring, the availability of more durable and better

prosthetics, and new drug-delivery systems for potentially harmful drugs.

While products based on nanotechnology are actually reaching the market, sufficient

knowledge on the associated toxicological risks is still lacking. The size reduction of

structures to nano level results in distinctly different properties. As well as the

chemical composition, which largely dictates the intrinsic toxic properties, very small

size appears to be a dominant indicator for drastic or toxic effects of particles.

2.1 What Makes Nanostructures Unique

Nanoscale particles are not new in either nature or science. However, the recent leapsin areas such as microscopy have given scientists new tools to understand and take

advantage of phenomena that occur naturally when matter is organized at the

nanoscale. In essence, these phenomena are based on ―quantum effects― and other

simple physical effects such as expanded surface area (more on these below). In

addition, the fact that a majority of biological processes occur at the nanoscale gives

scientists models and templates to imagine and construct new processes that can

enhance their work in medicine, imaging, computing, printing, chemical catalysis,materials synthesis, and many other fields. Nanotechnology is not simply working at

ever smaller dimensions; rather, working at the nanoscale enables scientists to utilize

the unique physical, chemical, mechanical, and optical properties of materials that

naturally occur at that scale.

2.1.1 Scale at which quantum effects dominates the property of materials

When particle sizes of solid matter in the visible scale are compared to what can be seen in aregular optical microscope, there is little difference in the properties of the particles. But when


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particles are created with dimensions of about 1 – 100 nanometers (where the particles can be

―seen‖ only with powerful specialized microscopes), the materials‘ properties change

significantly from those at larger scales. This is the size scale where so-called quantum effects

rule the behavior and properties of particles. Properties of materials are size-dependent in this

scale range. Thus, when particle size is made to be nanoscale, properties such as melting

point, fluorescence, electrical conductivity, magnetic permeability, and chemical reactivity

change as a function of the size of the particle.

Nanoscale gold illustrates the unique properties that occur at the nanoscale. Nanoscale

gold particles are not the yellow color with which we are familiar; nanoscale gold can

appear red or purple. At the nanoscale, the motion of the gold‘s electrons is confined.

Because this movement is restricted, gold nanoparticles react differently with light

compared to larger-scale gold particles. Their size and optical properties can be put to

practical use: nanoscale gold particles selectively accumulate in tumors, where they

can enable both precise imaging and targeted laser destruction of the tumor by means

that avoid harming healthy cells.

A fascinating and powerful result of the quantum effects of the nanoscale is the

concept of ―tunability‖ of properties. That is, by changing the size of the particle, a

scientist can literally fine-tune a material property of interest (e.g., changingfluorescence color; in turn, the fluorescence color of a particle can be used to identify

the particle, and various materials can be ―labeled‖ with fluorescent markers for

various purposes). Another potent quantum effect of the nanoscale is known as

tunneling which is a phenomenon that enables the scanning tunneling microscope and

flash memory for computing.

2.1.2 Scale at which much of biology occurs

Over millennia, nature has perfected the art of biology at the nanoscale. Many of the

inner workings of cells naturally occur at the nanoscale. For example, hemoglobin, the

protein that carries oxygen through the body, is 5.5 nanometers in diameter. A strand

of DNA, one of the building blocks of human life, is only about 2 nanometers in

diameter.

Drawing on the natural nanoscale of biology, many medical researchers are working

on designing tools, treatments, and therapies that are more precise and personalized

than conventional ones — and that can be applied earlier in the course of a disease and


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lead to fewer adverse side-effects. One medical example of nanotechnology is the bio-

barcode assay, a relatively low-cost method of detecting disease-specific biomarkers

in the blood, even when there are very few of them in a sample. The basic process,

which attaches ―recognition‖ particles and DNA ―amplifiers‖ to gold nanoparticles,

was originally demonstrated at Northwestern University for a prostate cancer

biomarker following prostatectomy. The bio-barcode assay has proven to be

considerably more sensitive than conventional assays for the same target biomarkers,

and it can be adapted to detect almost any molecular target.

Growing understanding of nanoscale biomolecular structures is impacting other fields

than medicine. Some scientists are looking at ways to use nanoscale biological

principles of molecular self-assembly, self-organization, and quantum mechanics to

create novel computing platforms. Other researchers have discovered that in

photosynthesis, the energy that plants harvest from sunlight is nearly instantly

transferred to plant ―reaction centers‖ by quantum mechanical processes with nearly

100% efficiency (little energy wasted as heat). They are investigating photosynthesis

as a model for ―green energy‖ nanosystems for inexpensive production and storage of

nonpolluting solar power.

2.2.3 Large Surface to Volume ratio

Nanoscale materials have far larger surface areas than similar masses of larger-scale

materials. As surface area per mass of a material increases, a greater amount of the

material can come into contact with surrounding materials, thus affecting reactivity.

A simple thought experiment shows why nanoparticles have phenomenally high

surface areas. A solid cube of a material 1 cm on a side has 6 square centimeters of

surface area, about equal to one side of half a stick of gum. But if that volume of 1

cubic centimeter were filled with cubes 1 mm on a side, that would be 1,000

millimeter-sized cubes (10 x 10 x 10), each one of which has a surface area of 6

square millimeters, for a total surface area of 60 square centimeters. When the 1 cubic

centimeter is filled with micrometer-sized cubes — a trillion (1012) of them, each with

a surface area of 6 square micrometers — the total surface area amounts to 6 square

meters. And when that single cubic centimeter of volume is filled with 1-nanometer-

sized cubes — 1021 of them, each with an area of 6 square nanometers — their total

surface area comes to 6,000 square meters. In other words, a single cubic centimeter


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of cubic nanoparticles has a total surface area 1 million times the total surface area of

1mm cube.

Fig. 2.3: Increasing surface area for the nanoparticles.

One benefit of greater surface area — and improved reactivity — in nanostructured

materials is that they have helped create better catalysts. As a result, catalysis by

engineered nanostructured materials already impacts about one-third of the huge

U.S. — and global — catalyst markets, affecting billions of dollars of revenue in the oil

and chemical industries. An everyday example of catalysis is the catalytic converter in

a car, which reduces the toxicity of theengine‘s fumes. Nano engineered batteries,

fuel cells, and catalysts can potentially use enhanced reactivity at the nanoscale to

produce cleaner, safer, and more affordable modes of producing and storing energy.

Large surface area also makes nanostructured membranes and materials idealcandidates for water treatment and desalination, among other uses. It also helps

support ―functionalization‖ of nanoscale material surfaces (adding particles for

specific purposes), for applications ranging from drug delivery to clothing insulation.

2.2 CHEMINANOTECHNOLOGY

The term Cheminanotechnology represents the most pervasive nanotechnology which

is applied to chemical processes. Most commentaries on nanotechnology start with


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reference to Eric Drexler, who is credited with coining the term, and then proceed to

discuss physicist Richard Feynman‘s assertion that there is plenty of room at the

bottom , by which he meant the advances that remain to be made in manipulating and

controlling things on the small scale. Nanotechnology can mean little machines that

will pump miniscule volumes of liquid, or it can refer to some new development in

fabrics that repel water. The term nanotechnology covers a whole range of very

different developments, ranging from nanostructuring of surfaces important to the

semi-conductor industry and biosensors, right up to nanoparticulate systems. The

latter are relevant to the finishing of synthetics or for catalytic processes in

'chemistry'. Because of this wide variety of applications, it is not easy to describe how

we benefit from nanotechnology.

Chemistry can be loosely described as the study of the formation, properties, and

interactions of molecules, while chemical engineering is the control of chemical

processes on a large scale. It has been known since at least the time of Lord Kelvin

and J.Williard Gibbs that the thermodynamic properties of a chemical substance are

not constant but are in fact affected by the size of the piece of the substance being

studied. For example, at 1 atm pressure water boils at 100 ºC. However, this is true

only of relatively large volumes of water. A droplet of water of 5 nm radius will boilat 95.9 ºC. The physics behind this has been understood for over a hundred years.

Similarly, melting points are affected by size; gold, which normally melts at 1064 ºC,

will melt at temperatures as low as 350 ºC when it is a 2 nm particle.

At the nanoscale, not only do these physical properties change but enthalpies of

fusion, vaporization, and chemical reaction change. These can affect the equilibrium

of a chemical reaction or can lead to chemical reactions being possible that do not

take place on larger particles. An early example is the observed change in the nickel-nickel carbonyl equilibrium. A more recent example is the discovery that small

particles of gold exhibit catalytic behavior. Previous studies on larger particles of gold

showed no catalytic activity, and the change is known to be chemical rather than

depend upon the increase in surface area per mass as a substance is divided up into

smaller pieces. Properties thought to be characteristics of the substance start to

become inconstant at small sizes, and at the nanometer level the effects have dramatic

results.


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It is not only chemical reactions but also fluid flows that change at small size. When

dealing with liquids at small scales, that indispensable engineering concept, the Reyn-

olds number (the dimensionless ratio of viscosity to momentum) is usually less than

unity, and handling fluids becomes quite a different task with the intuitive notions of

the flow and behaviour of a liquid being overturned.

We now have techniques that can look at, or work with, single molecules to establish

the properties of molecules individually rather than as an average of a collection. A

good example here is the scanning probe microscope (SPM) that enables us to

visualize single atoms and even electron waves in a way we may never have thought

possible. Now we can see defects in surfaces at which catalysis may be occurring,

whereas previously we knew that they must exist but could only infer their properties by other means. We can stretch single molecules and obtain directly physical

properties and thermodynamic data from force measurements on the single molecule

rather than the large numbers of molecules in a calorimeter or a spectrophotometer.

We can look at the effect of possible new drugs on a single live bacterium rather than

on a whole population of bacteria.

Not only do we have new techniques but we have new materials that were not

available previously. Challenges still lie in determining how these new products can be used, but they are providing opportunities for new and innovative exploration into

fields ranging from medicine to mineral processing. Examples include carbon nano-

tubes and titanium dioxide nanotubes. We can now use our understanding of the

adhesion forces we observe in nature, such as a gecko clinging to a wall solely by

means of van der Waals forces, and mimic these structures in synthetic adhesive

materials. A further spectroscopic technique of interest to chemists is surface-

enhanced Raman spectroscopy whereby the signals can be enhanced up to 1015 timesfor molecules adsorbed onto clusters of small particles of gold or silver. Advances in

technology will therefore be dependent on corresponding progress in application

technology, which will have to supply cost-effective processes in particular, such as

modern dispersant technologies, emulsifying and encapsulation processes,

precipitation, gas-phase reactions and suitable grinding techniques

The blurring of the traditional disciplinary boundaries between chemistry, physics,

and chemical engineering is reflected in the lack of clear distinctions between the


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branches that make up nanotechnology. Nevertheless,cheminanotechnology can be

delineated as a subset of nanotechnology that is focused on understanding the effect

that very small size has on chemical reactions, and the subsequent use of this

understanding in new product and process development.

2.3 Application of Nanoparticles

Fig.2.4: Application of nanotechnology


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CHAPTER 3

SYNTHESIS OF NANOPARTICLES

3.1 Introduction:

Verbally ―Synthesis‖ refers to the consolidation of ideas into a complex whole one.

Chemical synthesis is a purposeful execution of chemical reactions to obtain a

product, or several products. This happens by physical and chemical manipulations

usually involving one or more reactions. In modern laboratory usage, this tends to

imply that the process is reproducible, reliable, and established to work in multiple

laboratories. A chemical synthesis begins by selection of compounds that are known

as reagents or reactants. Various reaction types can be applied to these to synthesize

the product, or an intermediate product.

3.2 Sample collection

Electroplating waste sludge was collected in the form of liquid from one of the

electroplating industries in Aligarhtitled as ―M/s. Player Locks, Aligarh‖ , in which

Nickel, Chromium, Zinc and Cadmium plating is done, associated mostly of lock and

other allied industries. There are more than 5000 number of big and small plants are

working. These plants generate large quantity of waste. The quantity of articles plated,

depends on shape, property desired for various articles. This industry is having 130 ×

20 × 75 cm size tanks for collecting wastes of Nickel, Chromium, Zinc and Cadmium

etc. There is no appropriate arrangement for proper disposal of these wastes, generally

these wastes are disposed off directly in the drains without any treatment causing

environmental and ground water pollution in the disposal area.

Fig 3.1: Procured waste samples


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Fig 3.2: Electroplating Unit

Fig 3.3 Tanks Containing Waste

3.3 Methods and Materials:

In our present work Nickel oxide nano particles were successfully synthesised by

chemical route in which sucrose and honey were used as precursor and sodium

hydroxide was required for maintaining the homogeneity and ph value of the solution

and helps to make a stoichiometric solution to get Nickel oxide nanoparticles.


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1) The sample which we procured was first of all subjected to heating up to a

temperature of around 85-90º C. Afterwards heated sample was stirred and during

this continuous stirring 50gm of sodium hydroxide solution was added.

Fig 3.4 Heating and Stirring of Sample.

For the purpose of stirring and heating a magnetic stirrer was used. In magnetic

stirring the given sample is subjected to a rotating magnetic field and a small magnet

is dropped in the sample. As the magnetic field alters in direction in a circular path the

magnet also moves in this direction and we get a continuous stirring. The stand (on

which sample is placed) also serves for the purpose of heating as there are induction

plates on it. By this mechanism both heating and agitation operations are served at the

same place without much hassle.

2) After the addition of NaOH, around 1 hour later, in the state of continuous stirring,

50 gm. sucrose and 10 g honey were added to the sample. After 5 hours of

continuous stirring and heating a thick tar like solution was obtained.


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Fig 3.5 Product after Stirring and Heating

Fig 3.6 Product taken in Petri dish

3) For the further analysis and operation we needed to check its solubility in water

and we came to conclude that our product was water soluble.


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Fig 3.9 Product kept in vacuum oven for drying

Fig 3.10 Product obtained after drying

5) After this much heating, this dried product was transferred to a muffle furnace

where it was subjected to a high temperature of about 500º C for 2 hours. Heating

in muffle furnace was required because our product vas a very thick fluid rather

than a solid. This would have created glitches in comminution.


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Figure 3.11 Muffle furnace

6) The ultimately dried product obtained after this was grinded to make a fine powder

by using simple pestle and mortar

Fig 3.12 Pestle and mortar Fig 3.13 Fine powder obtained

The fine powder so obtained is our anticipated product, i.e. Nickel\ Nickel oxide nano

particles. Now to check whether the product thus obtained is the looked-for product or

not, if yes then what is its structure and configuration, we need certain

characterisation techniques to ascertain all these.

In these techniques we are confronted by various methodology of testing like XRD,

SEM, FTIR, and UV Visible. All these are elaborated in the ensuing chapter.


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heat stability, behaviour towards ultra violet light and etc.. The most common

techniques are shown in the table above.

4.1 Scanning Electron Microscopy

The scanning electron microscope (SEM) uses a focused beam of high-energy

electrons to generate a variety of signals at the surface of solid specimens. The signals

that derive from electron reveal information about the sample including external

morphology (texture), chemical composition, and crystalline structure and orientation

of materials making up the sample. In most applications, data are collected over a

selected area of the surface of the sample, and a 2-dimensional image is generated that

displays spatial variations in these properties. Areas ranging from approximately 1 cm

to 5 microns in width can be imaged in a scanning mode using conventional SEM

techniques (magnification ranging from 20X to approximately 30,000X, spatial

resolution of 50 to 100 nm). The SEM is also capable of performing analyses of

selected point locations on the sample; this approach is especially useful in

qualitatively or semi-quantitatively determining chemical compositions (using EDS),

crystalline structure, and crystal orientations.

Fig 4.1: Scanning Electron Microscope at USIF-AMU


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4.2 Energy Dispersive Spectroscopy

EDS makes use of the X-ray spectrum emitted by a solid sample bombarded with a

focused beam of electrons to obtain a localized chemical analysis. All elements from

atomic number 4 (Be) to 92 (U) can be detected in principle, though not all

instruments are equipped for ‗light‘ elements (Z < 10). Qualitative analysis involves

the identification of the lines in the spectrum and is fairly straightforward owing to the

simplicity of X-ray spectra. Quantitative analysis (determination of the concentrations

of the elements present) entails measuring line intensities for each element in the

sample and for the same elements in calibration Standards of known composition.

Energy-dispersive spectrometers (EDSs) employ pulse height analysis: a detector

giving output pulses proportional in height to the X-ray photon energy is used inconjunction with a pulse height for analyser (in this case a multichannel type). A solid

state detector is used because of its better energy resolution. Incident X-ray photons

cause ionization in the detector, producing an electrical charge, which is amplified by

a sensitive preamplifier located close to the detector. Both detector and preamplifier

are cooled with liquid nitrogen to minimize electronic noise. Si(Li) or Si drift

detectors (SDD) are commonly in use.

Fig 4.2: EDS Detector.


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4.3 Fourier Transform Infrared Spectroscopy

In the region of longer wavelength or low frequency the identification of different

types of chemicals is possible by this technique of infrared spectroscopy and the

instrument requires for its execution is Fourier transform infrared (FTIR)spectrometer. The spectroscopy merely based on the fact that molecules absorb

specific frequencies that are characteristic of their structure termed as resonant

frequencies, i.e. the frequency of the absorbed radiation matches the frequency of the

bond or group that vibrates. And the detection of energy is done on the basis of shape

of the molecular potential energy surfaces, the masses of the atoms, and the associated

vibronic coupling. As each different material is a unique combination of atoms, no

two compounds produce the exact same infrared spectrum. Therefore, infrared

spectroscopy can result in a positive identification (qualitative analysis) of every

different kind of material. In addition, the size of the peaks in the spectrum is a direct

indication of the amount of material present. FTIR can be used to analyse a wide

range of materials in bulk or thin films, liquids, solids, pastes, powders, fibers, and

other forms. FTIR analysis can give not only qualitative (identification) analysis of

materials, but with relevant standards, can be used for quantitative (amount) analysis.

FTIR can be used to analyse samples up to ~11 millimetres in diameter, and either

measure in bulk or the top ~1 micrometre layer. FTIR spectra of pure compounds are

generally so unique that theyare like a molecular ―fingerprint‖.

Fig 4.3: FT-IR Instrument at Department of Applied Physics.


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4.4 Differential Scanning Calorimetry (DSC)

Thermal Analysis (STA) generally refers to the simultaneous application of

Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC) to one and

the same sample in a single instrument. The test conditions are perfectly identical for

the TGA and DSC signals (same atmosphere, gas flow rate, vapour pressure of the

sample, heating rate, thermal contact to the sample crucible and sensor, radiation

effect, etc.).Thus, Thermal analysis (TA) is a group of techniques in which changes of

physical or chemical properties of the sample are monitored against time or

temperature, while the temperature of the sample is programmed which may involve

heating or cooling at a fixed rate, holding the temperature constant (isothermal), or

any sequence of these.

Fig 4.4: TGA & DSC at Department of Applied Physics

4.4.1 Working of DSC

The sample and reference chambers are heated equally into a temperature regime in

which a transformation takes place within the sample. As the sample temperature

deviates from the reference temperature, the device detects it and reduces the heat

input to one cell while adding heat to the other, so as to maintain a zero temperature


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difference between the sample and reference. The quantity of electrical energy per

unit time which must be supplied to the heating element in order to maintain null

balance is assumed to be proportional to the heat released per unit time by the sample.

4.4.2 Working of TGA

Measurements of changes in sample mass with temperature are made using a thermo

balance. This is a combination of a suitable electronic microbalance with a furnace

and associated temperature programmer. The balance should be in an enclosed system

so that the atmosphere can be controlled. Y axis is %mass loss; X axis is temp (or

time, since usually a linear heating rate). As the specimen changes weight, its

tendency to rise or fall is detected by LVDT. A current through the coil on the

counterbalance side exerts a force on the magnetic core which acts to return the

balance pan to a null position. The current required to maintain this position is

considered proportional to the mass change of the specimen.

4.5 X-Ray Diffraction (XRD)

Till 1895 the study of matter at the atomic level was a difficult task but the discovery

of electromagnetic radiation with 1 Å (10-10 m) wavelength, appearing at the region between gamma-rays and ultraviolet, makes it possible. As the atomic distance in

matter is comparable with the wavelength of X-ray, the phenomenon of diffraction

find its way through it and gives many feasible results related to the crystalline

structure. The unit cell and lattices which are distributed in a regular three-

dimensional way in space forms the base for diffraction pattern to occur. These

lattices form a series of parallel planes with its own specific d-spacing and with

different orientations exist. The reflection of incident monochromatic X-ray fromsuccessive planes of crystal lattices when the difference between the planes is of

complete number n of wavelengths leads to famous Bragg‘s law:

2d Sinθ = nλ

Where n is an integer 1, 2, 3….. (Usually equal 1), λ is wavelength in angstroms, d is

interatomic spacing in angstroms, andθ is the diffraction angle in degrees. Plotting

the angular positions and intensities of the resultant diffracted peaks of radiation

produces a pattern, which is characteristic of the sample.


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Fig4.5 X-ray Diffraction in accordance with Bragg‘s Law

Fig 4.6: XRD Apparatus at Department of Physics-AMU

Measurement conditions:

X-ray tube

Target = Cu

Voltage = 40.0 (kV)

Current = 30.0 (mA)

Slits

Divergence slit = 1.00000 (deg)

Scatter slit = 1.00000 (deg)

Receiving slit = 0.30000 (mm)


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Scanning

Scan range = 20.000 - 80.000

Scan mode = Continuous Scan

Scan speed = 2.0000 (deg/min)

Sampling pitch = 0.0200 (deg)

Preset time = 0.60 (sec)

4.6 UV Visible Spectroscopy

The wavelength of UV is shorter than the visible light. It ranges from 100 to 400 nm.

In a standard UV-V is spectrophotometer, a beam of light is split. one half of the

beam (the sample beam) is directed through a transparent cell containing a solution ofthe compound being analysed, and one half (the reference beam) is directed through

an identical cell that does not contain the compound but contains the solvent. The

instrument is designed so that it can make a comparison of the intensities of the two

beams as it scans over the desired region of the wavelengths. If the compound absorbs

light at a particular wavelength, the intensity of the sample beam (IS ) will be less than

that of the reference beam. Absorption of radiation by a sample is measured at various

wavelengths and plotted by a recorder to give the spectrum which is a plot of thewavelength of the entire region versus the absorption (A) of light at each wavelength.

And the band gap of the sample can be obtained by plotting the graph between (αhν

v/s hν) and extrapolating it along x -axis.

Fig 4.7: UV Visible Spectrometer at Centre of Excellence in Nano Materials, Dept. of

Applied Physics-AMU.


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CHAPTER 5

RESULTS AND DICUSSION

5.1 X-Ray Diffraction Analysis

The synthesized nanoparticles were characterized by powder X-ray diffractometer.

Fig.5.1 shows the X-ray diffraction spectrum of NiO sample. This shows crystalline

structure with 7 peaks. The XRD pattern shows a significant amount of line

broadening which is a characteristic of nanoparticles. The XRD pattern exhibits

prominent peaks at 31.4°, 43.3°, and 63°.

Fig. 5.1: X-ray diffraction spectrum of NiO sample

The crystal size can be calculated according to Debye-Scherrer formula .

…………………………….….... (1)


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Where k=0.9, λ is the wavelength of the Cu -Kα radiations, β is the full width at half

maximum and θ is the angle obtained from 2θ values corresponding to maximum

intensity peak in XRD pattern. The mean crystal size of NiO nanoparticle is 8.25 nm.

The inter planar distance was calculated using Bragg’s Law .

2d Sinθ = nλ ……………………………………....... (2)

Where, n was taken as 1. The value of d for the most intense peak was 2.846Å. The

Diffraction peaks thus obtained from X-ray diffraction data are in good agreement

with the standard pattern of NiO .

5.2 XRD - Crystallinity Index

It is generally agreed that the peak breadth of a specific phase of material is directly

proportional to the mean crystallite size of that material. From our XRD data, a peak

broadening of the nanoparticles is noticed. The average particle size, as determined

using the Scherrer equation, is calculated to be 8.25 nm. Crystallinity is evaluated

through comparison of crystallite size as ascertained by SEM particle size

determination.

Crystallinity index Eq. is presented below:

……….... (3)

(Icry ≥ 1.00)

Where Icry is the crystallinity index; Dp is the particle size (obtained from either

TEM or SEM morphological analysis); Dcry is the particle size (calculated from the

Scherrer equation).

Table 5.1: The crystallinity index of Nickel Oxide Nanoparticles

Sample D p (nm) D cry (nm) I cry Particle Type

NiO nanoparticles 100 8.25 12.12 Polycrystalline

Table 5.1 displays the crystallinity index of the sample that scored higher than 1.0.

The data indicate that the NiO is highly crystalline. If Icry value is close to 1, then it is

assumed that the crystallite size represents monocrystalline whereas a polycrystalline

have a much larger crystallinity index.


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5.3 XRD - Specific Surface Area

Specific surface area (SSA) is a material property. It is a derived scientific value that

can be used to determine the type and properties of a material. It has a particular

importance in case of adsorption, heterogeneous catalysis and reactions on surfaces.SSA is the Surface Area (SA) per mass.

SSA = ……………………………. (4)

Here, Vpart is particle volume and SApart is particle Surface area

…………………………....... (5)

Where S is the specific surface area, Dpis the size of the particles, and is the densityof NiO 6.67 g cm-3. Mathematically, SSA can be calculated using these formulas 4

and 5. Both of these formulas yield same result. Calculated value of (SA = 213 nm2,

Volume= 295 nm3 and SSA = 109 m2 /g) prepared NiO nanoparticles are presented in

Table 5.2

Table 5.2: Specific Surface Area of Nickel oxide Nanoparticles

Particle

Size (nm)

Surface

Area (nm 2)

Volume

(nm 3)

Density

(g/cm -3)

SSA

(m 2/g)

Surface

area to

volume

ratio

8.25 213 295 6.67 109 0.722

5.4 SEM Analysis

The surface morphological features of synthesized nanoparticles were studied by

scanning electron microscope. Fig 5.2; 5.3; 5.4 shows the SEM image of NiO

nanoparticles with magnification of 1600, 1000 and 2500 respectively. The

instrumental parameters, accelerating voltage, spot size, and magnification and

working distances are indicated on SEM image. The results indicate that mono-

dispersive and highly crystalline NiO nanoparticles are obtained. The appearance of

some particles is in spherical shape and some are in rod shape. We can observe that

the particles are highly agglomerated and they are essentially cluster of nanoparticles.


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The SEM picture indicates the size of polycrystalline particles. The observation of

some larger nanoparticles may be attributed to the fact that NiO nanoparticles have

the tendency to agglomerate due to their high surface energy and high surface tension

of the ultrafine nanoparticles. The fine particle size results in a large surface area that

in turn, enhances the nanoparticles catalytic activity. So we can conclude that the

prepared NiO particles are in nanometre range. The average diameter of the particle

observed from SEM analysis is 100 nm, which is larger than the diameter predicted

from X-Ray broadening.

Fig 5.2: SEM image of nickel oxide nanoparticles at 1600 magnification


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Fig. 5.3: SEM image of nickel oxide nanoparticles at 1000 magnification

Fig. 5.4: SEM image of nickel oxide nanoparticles at 2500 magnification


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5.5 EDS Analysis

Fig 5.5: EDS spectrum for NiO nanoparticle

Fig 5.6: Weight % elemental analysis in NiO nanoparticle sample


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Table 5.3: % analysis of different elements in NiO nanoparticles by EDS

Element Approx. conc. Weight % Atomic %

O 0.45 14.85 32.69

Na 0.13 10.52 16.12S 0.20 7.96 8.74

Cl 0.14 6.22 6.18

Ni 1.81 60.46 36.27

Total 100

Fig 5.7: Position of different elements in the electron image


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5.6 FT-IR Analysis

Fig 5.8 shows Fourier transformed spectrum of NiO nanoparticles at room temp. The

spectrum was recorded in the range of 4000cm-1 – 400cm-1. The FTIR spectrum

shows the characteristics peaks at 460cm-1

, 540 cm-1

, 555 cm-1

, 560 cm-1

, 3250 cm-1

,3310 cm-1 , 3405 cm-1 . The band at 460 cm-1 reveals the presence of NiO. Despite

drying this sample contained traces of water (peaks at 3250 cm-1, 3310 cm-1). The

other peaks indicate the presence of impurities. This shows that the sample contains

some impurity. The same chemical composition is confirmed by the XRD pattern.

Fig 5.8: FT-IR Spectra of NiO nanoparticles.


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As subjected to DSC, a graph is obtained shown in Fig 5.10. A peak is found at 225

°C and an upward peak shows the endothermic reaction. This peak is probably due to

dehydration reactions, due to the loss of water. Also the rate of heat flow is increased

exponentially afterwards.

Fig 5.10: DSC spectra of NiO nanoparticles.


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6.2 Propellant additive

Adding nickel nanoparticles to solid (rocket fuel) propellant increases combustion

heat, combustion efficiency and combustion stability.

Fig 6.2 Use in rocket propellant

6.3 Conductive paste

Conductive paste is commonly used for wiring and packaging. In the microelectronics

industry, it plays an important role in the miniaturization of electronic devices and

circuits.

6.4 High-performance electrodes

Nickel nanoparticles can be made into electrodes with a large surface area to

considerably improve energy density.

Fig 6.3 Depicting use in High performance electrode


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6.5 Sintering additive

As an additive, Ni nanoparticles can effectively reduce sintering temperatures of

metals and ceramics.

6.6 Conductive coating

A coating of Ni nanoparticles can be prepared in an inert environment and below the

melting point of the bulk metal

Figure 6.4 Conductive coating.

6.7 Synthetic skin

A synthetic skin that may be used in prosthetics has been demonstrated with both self-

healing capability and the ability to sense pressure. The material is a composite

of nickel nanoparticles and a polymer . If the material is held together after a cut it

seals together in about 30 minutes giving it a self-healing ability. Also the electrical

resistance of the material changes with pressure, giving it sense ability like touch.

Fig 6.5 Artificial skin


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CONCLUSION

Nanostructured particles of NiO have been successfully synthesized from the

electroplating industry waste. XRD, SEM, EDS, FT-IR, UV-Visible, DSCcharacterizations studies have also been done for the synthesized nanoparticles.

XRD results estimate the average particle size as 8.25 nm and the specific surface area

is 109 m2/g having a surface to volume ratio as 0.722. It also confirms the high degree

crystallinity i.e. polycrystalline nature of the prepared sample.

SEM confirms that the particles are in nano size and the appearance of some particles

is in spherical shape and some are in rod shape. EDS analysis clearly indicates the

presence of Nickel, Oxygen, Sodium, Chlorine and Sulphur with the highest percentage of Nickel as 60.4%. The FTIR spectrum confirms the presence of NiO

nanoparticles. DSC analysis gives an idea about the heat flow in the sample and its

stability. This simple, novel and cost effective synthesis method with the economical

and environmental handling of the hazardous waste of electroplating industries and

will be useful for industries for the preparation of nickel oxide nano-sized particles.


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Synthesis of NiO Nanoparticles from Industrial Waste

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