Groundwater is the most commonly found freshwater
source in the world, groundwater supplies for nearly half of all drinking water
requirements of the world population and about 43% of the global consumptive
use in irrigation is also fulfilled by groundwater. Therefore the quality of
groundwater is very important than any other water resource referring the
health of human and all other living beings
Presence of fluoride and hardness excessively in
ground water is considered a serious problem in public health point of view. In
Sri Lanka, excessive fluoride and hardness in groundwater has proven to be a
serious issue due to most of rural domestic water requirements is fulfilled by
groundwater. Recent researches confirm that groundwater in districts such as Anuradhapura
and Monaragala contained fluoride exceeding the desired value. Also some
researches were claimed that Jaffna, Hambanthota, Vavuniya and Anuradhapura
exceeding maximum level of hardness.
Modified fly ash has an ability to remove toxic in
water like hardness and fluoride. But
modified fly ash alone is unable to remove those toxic due to their particle
sizes, which has reduced its adsorption capacity and stability in water too.
Therefore, modified fly ash is needed some material which has huge amount of
pore in its surface for anchoring to increase their stability in water and
enhances reactive performance. Graphene
oxide has those characteristic mentioned above. Therefore grapheme oxide and
modified fly ash composite can be a good toxic remove material. Hence, the
study focuses to impregnate modified fly ash in graphene oxide matrix and
evaluates the properties and performance in removal of hardness and fluoride in
OF THE PROBLEM
Excessive hardness and fluoride cause lot of health
problems recent years around the world as well as srilanka. Chronic kidney
disease of unknown etiology (CKDu) is the main problem occurred. Latest
research reveals that areas with groundwater containing high fluoride
concentrations and very hard water overlap with CKDu affected areas. Other than
that dental fluorosis, skeletal fluorosis, low IQ and mental retardation are
spread due to these toxic in water.
OF THE RESEARCH
When selecting a treating method for this kind of
research, it is important to consider the cost, availability of materials,
level of removal required and testing procedures. Fly ash and grapheme oxide
are very easy to produce and not much expensive as well. Fly ash is a waste
product of the coal power plants.
Removal of water toxic is important because water or
water resources cannot replace by any material. Shortage of drinking water is a
major problem for several countries. In srilanka, dry zone has faced this
problem for a long time. Results of this research can be useful for anyone who
interested in these issues.
People who live in the dry zone and agricultural areas
are main stakeholders of this research. Also the industry could refer the
results to improve their water treating systems.
SCOPE AND LIMITATIONS
OF THE STUDY
Concentration of fluoride and hardness, pH and flow rate are the proposed
variables to be studying in the research. Preparing graphene oxide/fly ash is
the most time consuming work of the research.
There are two main objectives
in this research. The main of this research is to check whether fly ash and
grapheme oxide composite has an ability to reduce the fluoride and hardness
level of the water to the drinking water range. Other objective is to improve
the fly ash/graphene oxide composite as much as possible.
Moderately hard water is approved for drinking. Fluoride concentration of
the drinking water should be 0.6-1.0 mg/L.
There will be few steps in the research progress.
of grapheme oxide /fly ash composite at the laboratory
Identify the characteristics of the composite
using following analysis methods.
morphological characteristic (size, shape, surface element)
(Scanning Electron Microscopy)
Analysis about composition, functional groups
(Fourier Transform Infrared Spectroscopy)
of water containing hardness and fluoride
As the first step of testing I have to prepare
15 specimen containing prepared water 100ml.
Then insert the fly ash/ graphene oxide composite 1g for each. After 4
hours filter the water and test for hardness and fluoride concentration.
Langmuir isotherm Langmuir’s
isotherm model suggests that uptake occurs on homogeneous surface by monolayer
sorption without interaction between sorbed molecules This model is based on
the assumption that maximum adsorption corresponds to a saturated monolayer of
solute molecules on the adsorbent surface, with no lateral interaction between
the sorbed molecules The Langmuir isotherm model can be represented in the form
of equation as follows;
Where qe is the
amount of adsorbate adsorbed per unit weight of adsorbent at equilibrium
(mg/g), qmax is the maximum adsorption capacity (mg/g), b is the
Langmuironstant that relates to the energy of adsorption (L/mg), and Ce
is the equilibrium concentration of adsorbate in solution (mg/L).
In order to find out the further feasibility of the isotherm, the essential
characteristics of the Langmuir isotherm can be described by an equilibrium
parameter RL as in Equation
Where C0 is the initial concentration of fluoride in mg/l and
RL indicates the nature of the
adsorption process, as given below;
• RL > 1 Unfavorable
• RL = 1 Linear