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Abstract Graphene oxide is synthesized by Hummers method from graphite. Graphene is prepared using three different methods after the chemical reduction of graphene oxide. Then covalent and noncovalent functionalization are achieved for the graphene surface by different amines as aniline and 1,6-diaminohexane. Silver nanoparticles (AgNPs) were deposited on the surface of the functionalized graphene during the synthesis process through the chemical reduction of silver nitrate (AgNO3) by hydrazine hydrate. The disinfection effect was successfully tested against total and fecal coliforms found in water samples from different regions in Egypt. The changes in surface functionalities and bonding nature were studied by X-ray diffraction (XRD), Raman spectroscopy, nuclear magnetic resonance (NMR) and infrared spectroscopy (IR). The morphology and size distribution were studied by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM), where the successful immobilization of silver nanoparticles on the graphene surface was studied. The following summarizes the experimental work undertaken in this thesis. 1- Preparation of graphene oxide Graphite is converted chemically to graphene oxide following Hummers Offman method (1) according to: Graphite + H2SO4 (conc, 98%) + KMnO4+ NaNO3 Graphene oxide. 2- Preparation of graphene Graphene is prepared chemically from graphene oxide (graphene-COOH) or graphite oxide (as will be explained later) according to the following: Graphene oxide or graphite oxide (graphene-COOH) Graphene-CH2OH First method Graphite oxide(graphene-COOH) + NH4OH 30% Graphene-CH2OH Second method Graphene oxide (graphene-COOH) + NH2C6H5+ NH2NH2HCl Third method Graphene oxide (graphene-COOH) + NH2NH2.H2O 3- Preparation of graphene functionalized by aniline and silver nanoparticles: First method: (noncovalent functionalization) Reaction of aniline, silver nitrate and hydrazine hydrate with graphene oxide: (Graphene-COOH)+ NH2C6H5 + AgNO3 + NH2NH2.H2O → Graphene-COOH….. NH2C6H5…..AgNPs Second method: (noncovalent functionalization) Reaction of aniline, silver nitrate, hydrazine hydrate with graphene while heating: Graphene + NH2C6H5 + AgNO3 + NH2NH2.H2O Graphene….. NH2C6H5…..AgNPs Third method: (covalent functionalization) Reaction of graphene oxide with thionyl chloride, aniline, silver nitrate and hydrazine hydrate while heating in closed system: Graphene-COOH+ SOCl2 Graphene-COCl Graphene-COCl + NH2C6H5 → Graphene-CONH-C6H5 Graphene-CONH-C6H5 + AgNO3 + NH2NH2.H2O → Graphene- CONH-C6H5…..AgNPs 4- Preparation of graphene functionalized by 1, 6-diaminohexane and silver nanoparticles: First method (noncovalent functionalization) Reaction of graphene with hydrochloric acid, 1, 6-diaminohexane, silver nitrate and hydrazine hydrate according to: Graphene + HCl 30 % solution + H2NCH2─ (CH2)4─CH2NH2 + AgNO3 + NH2NH2.H2O → Graphene….. NH2 (CH2) 6 NH2 …..AgNPs Second method (covalent functionalization) Reaction of graphene oxide with thionyl chloride, 1, 6-diaminohexane, silver nitrate and hydrazine hydrate while heating in closed system: Graphene-COOH+ SOCl2 Graphene-COCl Graphene-COCl + NH2CH2CH2CH2CH2CH2CH2NH2 → Graphene-CONH─(CH2)6 ─NHCO-Graphene Graphene-CONH-(CH2)6-NHCO-Graphene + AgNO3 + NH2NH2.H2O → Graphene-CONH- (CH2) 6 -NHCO-Graphene…..AgNPs 5- Bacterial infection test Three ”untreated” infected water samples from three different regions in Benisweef governorate were treated according to: 0.1 g graphene aniline /silver nanocomposite /100 mL ” untreated ” water. This results in complete disinfection for all samples. Also, 0.1 g graphene 1,6-diaminohexane /silver nanocomposite /100 mL ” untreated ” water succeeded in disinfecting the water samples from Bahr El-Bakar and Kochainer sewages. Bacterial infection tests were conducted in the central laboratories of the Nile Research Institute of the National Water Research Center in Egypt according to the following procedure: Fecal coliform. Fecal coliforms density was determined using seven hours fecal coliforms test and applying membrane filter technique according to standard method (APHA, 1989). M-7h/FC ingredients were heated in boiling water bath then cooled to 55°C and pH value was adjusted to 7.3 before pouring in Petri dishes. After incubation at 41.5°C for 7 hours, yellow colonies were counted as fecal coliform bacteria. Stock solutions were prepared using the appropriate solvent as indicated or distilled water. Polluted (infected) water samples were collected according to environmental procedures following environmental protection agency regulations using sterilized glass containers. The samples were kept at low temperatures in ice bath and delivered to the laboratory for immediate testing. Infected water samples were collected from the Khour, mixing zone and the river, all from Benisweef governorate (Elwasta area, five kilometers along the Nile river from the 82.5 to 87.5 kilometers of the Nile river) and the samples collected from Bahr El-Bakar and Kochainer sewage water. |