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PhD Presentation March 2023.pptx

  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: 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.