CHAPTER ONE
INTRODUCTION
1.1 Background
Water is an essential substance for the existence of mankind on earth because of its vital
function to man and his environment. The sources of water are; surface water such as
streams, rivers, lakes, seas and oceans, ground water such as wells, boreholes, and rain water
which is obtained from the physical action of condensation of water vapour that evaporates
from the surface of the earth. The rain water replenishes underground and surface water. It is
interesting to note that 71% of the earth’s surface is covered by water. This is unevenly
distributed between seas and oceans, ground water, glaciers and ice cap and in air (as vapour
clouds and precipitation) in percentages of 96.5%, 1.7%, 1.7% and 0.001% respectively. Of
these, only 2.5% is fresh water and 98.5% of that water is ice and ground water.
With the increase in industrialisation, water pollution has been a major issue of hazard to
man and his environment. Water pollution as defined by Wikipedia is the contamination of
water bodies. These contaminants are classified as; physical contaminants (primarily impact
the physical appearance or other physical properties of water), biological contaminants
(organisms in water), radiological contaminants (chemical elements with an unbalanced
number of protons and neutrons resulting in unstable atoms that emit ionizing radiation) and
chemical contaminants (elements or compounds including nitrogen, bleach,, salts, pesticides,
toxins produced by bacteria, and human or animal dung and metal) of which this study falls
under. (USEPA, 2016). Two different groups are used to categorise the factors that are
instrumental in water pollution namely; point sources and non-point sources. (Menon, 2011).
Point sources are direct sources of water pollution that are identified and controlled (reduced
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and monitored) easily, some examples are factories, sewage systems, power plants,
underground coal mines, oil wells. Non point sources are ambiguously defined and harder to
control they include a wide range of sources such as; when rain or snow moves through the
ground and picks up pollutants as it moves towards a major body of water, the runoff of
fertilizers from farmland, air pollutants deposited on earth. This has necessitated the need for
water treatment process. (Menon, 2011).
The wellbeing of the environment, society and the economy is a factor of the quality of
water (Corcoran et al.; 2010). Waste water is water that has been negatively affected in
quality by anthropogenic influences. Wastewater is defined as a combination of one or more
of; domestic effluents consisting of black-water (excreta, water and faecal sludge) and grey
water (kitchen and bathing wastewater); water from commercial establishment and
institutions, including hospitals ; industrial effluent, storm water and other urban run-off;
agricultural, horticultural and aquaculture effluent, either dissolved or as suspended matter
(Corcoran et al; 2010).
Heavy metals are naturally occurring elements that play major roles in the industry. Heavy
metals present in trace amounts are required in some biological processes; Iron and copper
(oxygen and electron transport); zinc (hydroxylation); cobalt (complex syntheses and cell
metabolism) (Nielboer and Richardson, 1978) to mention but a few. Although heavy metals
have proven to be useful in the industry, some have negative effect on both the environment
and on man hence the need for their removal from waste water.
Methods such as chemical precipitation, chemical coagulation, ion-exchange,
electrochemical method, membrane process and ultrafiltration can be employed in removal of
heavy metals from water. The methods are relatively expensive and the agencies responsible
for the provision and distribution of potable water; water board, waste sewerage authority
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(WASA), rural urban development agency (RUDA), rural urban water supply agency
(RUWASA), water resources employ the conventional water treatment process (involving a
series of steps; aeration, coagulation, flocculation, sedimentation , clarification, filtration and
disinfection), which is sufficient in the removal of physical and biological contaminants only
and not chemical contaminants.
Research efforts has/is been made in the determination of a cheap, easily accessible and
replicated method of hard metal removal. In developing countries such as Nigeria, water
treatment plants are expensive. The ability to pay for services is minimal and skills as well as
technology are scarce. In other to alleviate the prevailing difficulties, approaches should be
focus on sustainable water treatment systems that are low cost, robust and requires minimal
maintenance and operating skills. Locally available materials can be exploited towards
achieving sustainable safe potable water supply (Aho and Lagasi, 2012). This makes
adsorption and the use of eggshell as an adsorbent a contender as a substitute method of water
treatment.
Heavy metals have a wide application in the industry, hence they are present in the
industrial effluents generated at the end of a process. They are introduced into the
environment during these effluents disposal and generally enter the body by ingestion,
inhalation and adsorption through the skin or mucous membrane (Jackson and Henderson,
2016) adversely affecting the system; environment and man. Methods of heavy metal
removal is therefore required and important to avoid this.
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1.2 Research Problem
The generation of waste water containing heavy metals has become an issue as their release
into the environment has increased as a result of industrialisation. This waste water contains
amounts of heavy metal that are harmful to the environment and man who is likely to come in
contact and use this water. Legislations have been put in place prompting industries to treat
the waste water they generate before it is disposed of. This increases the operational cost of a
manufacturing process and hence the need for a relatively cheap, easily accessible and
replicated method of waste water treatment. The need for the proper disposal of eggshell
currently being used as landfills also makes this study important.
1.3 Aim and Objectives
The aim of this research is to study the effectiveness of eggshell as an adsorbent in the
removal of cobalt ii ion from aqueous solution providing an affordable and easy substitute for
water treatment. The objectives are:
1. Preparation of adsorbent from waste chicken eggshell.
2. Characterisation of adsorbent using FTR, SEM, and XRD techniques.
3. Testing the adsorption capacity of as-synthesised eggshell adsorbent.
4. Optimisation of adsorption variables; contact time, temperature, adsorbent dosage and
initial concentration.
1.4 Research Scope and Limitation
To achieve the objective of this research, the listed scopes and limitations have been
identified.
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1. The scope of this research is limited to prepared aqueous solutions with known
concentration of copper and zinc ion, egg shell from chicken sourced from ABUAD
cafeteria.
2. The capacity of egg shell as an adsorbent will be investigated and evaluated.
3. Analytical tools easily found in ABUAD and surrounding institutions also serves as a
limitation.
4. The study is limited to inorganic contaminants that pollutes water.
1.5 Justification of study
The inefficiency of the government to provide potable water for her citizens coupled with
the increasing rate of pollution of the available fresh water mainly by heavy metal from the
industry has made the search for a cheap and easily replicated method of water treatment
common these days. The increasing rate of pollution caused by human activities
(industrialisation, waste generation and improper disposal), has stimulated the need for
environmental control measure. This study focuses on the removal of heavy metal from water
(waste water treatment) making it suitable for use and also on the reduce, reuse, and recycling
of eggshell. In addition to the provision of an alternative waste water treatment, it provides a
suitable means of egg shell disposal as improper disposal leads to inbreeding of rodents
which feed on the membrane, subsequently leading to the spread of disease such as rat bite
fever, leptospirosis and the most recent Lassa fever (Orkin LLC, 2016) and also attract its
predators; snakes.
The provision of cheap, simple and easily available method of waste water treatment to the
industries before their disposal as well as the masses affected by environmental pollution will
be achieved in the case of the success of this research as well as an avenue for eggshell
recycling solving the problem of improper disposal.
