3. Introduction and Literature Review
• Water is the most abundant and important
compound in the ecosystem, needed by all living
organisms for growth and survival.
• Due to increased human population,
industrialization, use of fertilizers and human
activities water is highly polluted.
• Impurities are introduced into water through
weathering of rocks and leaching of soils,
dissolution of aerosol particles from the
atmosphere, human activities e.g. mining and
processing and use of metal based materials
4. Introduction and Literature Review…..
• Poor quality of water threatens the growth of
economies and ecosystems and this limits the
quality of agricultural produce as well as
quality of manufactured products leading to a
decline in economic growth.
• Poor water quality has a direct impact on
water quantity as it limits the amount of water
available for industry and agriculture
5. Problem Statement
• More than half of the world’s population lives in areas
of water scarcity. This situation has been further
worsened by population increase, rapid
industrialization and urbanization contributing to water
pollution and scarcity. The use of synthetic polymers
that are non-renewable, non-biodegradable, expensive
and toxic in water filtration and treatment systems only
serves to worsen the situation.
• The long term use of chlorine in water treatment has
led to the rise of microbes that are resistant to
chlorination
6. Justification
• The rise in the use of petroleum based
products calls for the need to develop
renewable and sustainable materials for water
treatment and purification since the existing
materials used in water treatment are
synthetic polymers that are non-renewable,
non-biodegradable, inefficient, expensive and
toxic.
7. General Objective
• To formulate water treatment adsorbents for
removal of heavy metals from waste water.
8. Specific Objectives
• To extract chitin from spent pupa shells of black soldier fly insects
(Hermetia illucens) and characterize its properties using XRD and
SEM.
• To synthesize chitosan from chitin and characterize its properties
using XRD and SEM..
• To synthesize chitosan composites and characterize their properties
using XRD and SEM.
• To extract cellulose and alginate and characterize their properties
using XRD and SEM.
• To determine the effect of temperature, pH, adsorbent dosage and
contact time of composites on the removal of different pollutants
from waste water
• To determine the percentage adsorption capacity of the different
composites towards different pollutants such as heavy metals and
investigate their mechanism of action.
9. Materials and Methods
(Chitin Extraction)
• The extraction of chitin involves several processes such as
demineralization, deproteinization, deacetylation and
decolourization
• Demineralization/decalcification will be carried out using 1
N hydrochloric acid (analytical grade) at 100 °C for 20
minutes in order to get rid of minerals like calcium
carbonate.
• This will be followed by deproteinization using 1 N sodium
hydroxide (analytical grade) at 80 °C for 24 – 36 hours to
destroy protein tissues. The digestate will be filtered and
the residue washed with distilled water to obtain chitin.
The chitin will then be bleached using 6% sodium
hypochlorite solution
10. Development of Chitosan
• Chitosan will be obtained from chitin via
deacetylation process, in which in which
acetyl groups will be removed from chitin by
treating chitin with 40% sodium hydroxide
solution at 110 °C for 4 hours
11. Extraction of Cellulose
• Dried and finely ground plant materials will be
mixed with 10% NaOH solution and
continuously stirred for 3 hours at 100 °C then
mixed with peracetic acid in a 1:5 ratio. This
will be followed by stirring for 2 hours at 80 °C
after which the residue will be washed and
filtered then dried in an oven at 100 °C
12. Preparation of Polymer – Metal
Composites
• Nine polymer – metal complexes will be prepared: Ch–Fe, Ch–Co
and Ch–Ni; Ce-Fe, Ce-Co and Ce-Ni a well as Alg-Fe, Alg-Co and Alg-
Ni complexes.
• To 0.05 g of raw polymer, 10% hydrochloric acid will be added and
the mixture stirred. Insoluble residue will be removed by filtration.
Different metal salts (NiCl2, FeCl2 and Co(COOCH3)2 ) will be
dissolved in separate beakers containing polymer solution in 60 mL
of 0.1 M hydrochloric acid and heated at 60 °C for two hours to
ensure complete complexion of the metal ions with chitosan.
• In order to remove chloride ions, 0.5 M sodium hydroxide will be
added to the homogeneous mixture. The mixture will be filtered
and the polymer – metal complex particles washed with distilled
water to bring the pH to neutral, after which they will be dried in air
for 48 hours
13. Analytical Procedure
• Waste water for the analysis of heavy metals will be
collected in polyethylene containers pre washed with
detergents then soaked in 10% nitric acid for 12 hours
after which they will be rinsed using distilled water.
• The waste water will be analyzed for chemical
parameters (heavy metals) before and after passing
waste water through the different polymer –
composite membranes.
• The heavy metals under study will include lead,
chromium, copper, nickel, cobalt, cadmium, iron and
mercury.
14. Determination of Heavy Metals
• In the determination of heavy metals, 100 mL of
waste water sample will be placed in a 250 mL
conical flask then 5 mL of nitric acid, 5 mL of
hydrochloric acid and 5 mL of perchloric acid
added and the mixture heated on a hot plate in a
special blast shield fumehood until the volume
reduces to 10 mL.
• The digestate will then be filled to the 100 mL
mark of a volumetric flask using distilled water.
• The concentration of selected heavy metals will
be determined using FAAS
15. Data Analysis and Presentation
• The adsorption efficiency of the different chitosan
composites will be determined by subjecting the data to
different adsorption isotherm models. They include:
Langmuir adsorption isotherm, Freundlich adsorption
isotherm and the Brunauer – Emmett – Teller (BET)
adsorption Isotherm models.
• The adsorption process and the time needed for adsorption
as well as the rate of target sorbet uptake will be described
and predicted using adsorption kinetics.
• These will include the pseudo first order and pseudo
second order kinetic models. The data will then be
presented in form of line graphs, bar graphs and pie charts.
16. Work Plan
Project Period (3 years)
Task
Sept 2023 – Feb 2024 Feb – Aug 2024 Aug 2024 – Feb 2025 Feb – Aug 2025 Aug 2025 – Feb 2026 Feb – Aug 2026
Proposal writing, corrections
& submission and
procurement of chemicals and
reagents
Insect rearing and sampling
Preliminary studies
Development and testing of
adsorbents
Data analysis and
interpretation
Publications
Thesis writing and seminars
Thesis corrections and
submission
Thesis defense and
graduation
17. References
• Abdolmajid G. Majid K. Mitra G. and Mehdi F. (2013). Kinetic and isotherm studies of adsorption
and biosorption processes in the removal of phenolic compounds from aqueous solutions:
comparative study. Journal of environmental health, science and engineering, 11:29.
• Angela S. Cornelia I. Denisa F. Anton F. and Ecaterina A. (2021). Chitosan-Based Nanocomposite
Polymeric Membranes for Water Purification – A Review. Journal of materials, 14(2091).
• Athisa R. M. Scholastica M. V. Augustine A. P Tamizhdurai P. and Mangesh V. L (2021).
Biosynthesis, characterization biological and photocatalytic investigations of Elsholtzia blanda and
chitosan mediated copper oxide nanoparticles. Arabian journal of chemistry. 15, 103661.
• Bashir A. D. Abdo T. Abubakkar W. and Mazahar F. (2013). Isotherms and thermodynamic studies
on adsorption of copper on powder of shed pods of Acacia nilotica. Journal of environmental
chemistry and ecotoxicology, 5(2). Pp 17-20.
• Boniface Owino (2018). Enhancing access to safe water and improved sanitation services in Kenya.
A report on enhancing access to improved WASH services.
• Byju’s (2022). Adsorption isotherms. Retrieved from: https://byjus.com/chemistry/adsorption-
isotherms-applications/
• Chittaranjan Ray and Ravi Jain (2011). Drinking water treatment – strategies for sustainability
Springer Dordrecht Heidelberg, NewYork.
• Djamel G. (2017). Water treatment by chlorinaton: an updated mechanistic insight review.
Chemistry research journal. 2(4): 125 – 138.
• Howard Ching Chung (2011). Access to water and sanitation in the informal settlement of Kisumu,
Kenya. Msc thesis, human geography, University of Nairobi, Kenya.
