Azov, V. ALangner, E. H. G.Mzinjani, Viwe2023-10-132023-10-132023http://hdl.handle.net/11660/12314Dissertation (M.Sc.(Chemistry))--University of the Free State, 2023The availability of clean water to the community/ society is becoming a huge problem for its ecosystem. These toxic contaminants come from surface and subsurface water systems such as dams, rivers, and oceans that are eluted from industrial, domestic, agricultural, and recreational activities. Both organic and inorganic contaminants are found in these water systems in high concentrations, which put aquatic life at tremendous risk and the environment in general. Thus, the need for synthetic materials that can be used to solve this ongoing problem of water contamination is becoming an obvious research goal that needs urgent attention. Nanomaterials such as nanoparticles are currently being investigated as a tool to remove various contaminants in wastewater. Nanoparticles are very small particles with sizes ranging from 1 to 100 nm. Depending on their type, these nanomaterials may demonstrate various unique properties, such as strong catalytic activity, superparamagnetism, quantum confinement, and extremely high surface-to-volume ratios. In this project, the high surface-to-volume property was explored during the adsorption of methylene blue dye in spiked water samples. Magnetic iron oxide nanoparticles were chosen because of their magnetic susceptibility and most availability of iron metal on earth, making them cheaper materials since they can be prepared from cheap iron precursors. Magnetite NPs were prepared using the co-precipitation method, where iron precursors of Fe²⁺ and Fe³‏⁺ were dissolved in de-ionized water and ammonium hydroxide was used as the precipitating agent under an inert atmosphere. Better adsorption capacities of these nanoparticles can be achieved by functionalizing them with different organic and inorganic molecules. In this study, mono-alkyl phosphate esters of varying alkyl chain lengths were synthesized and used to functionalize the as-synthesized magnetite NPs to render better affinity towards organic dyes (Figure 1). The as-prepared magnetite NPs were characterized using techniques such as TEM, SEM, FTIR, EDS, and PXRD, and the organic functionalization molecules were characterized using NMR (¹H, ¹³C, and ³¹P), FTIR, and mass spectrometry. These characterization techniques confirmed the successful synthesis of the nanoparticles and mono-alkyl phosphate esters of varying alkyl chain lengths. TEM and SEM micrographs showed close to spherical shapes of the prepared nanoparticles with particle diameters ranging from 12 – 16 nm for bare Fe₃O₄ NPs and 17 – 22 nm for functionalized NPs. Comparable particle size was also obtained from the PXRD results using the Scherrer equation (eq. 3.1) where a particle size of 13 nm was obtained. PXRD characteristic peaks confirmed the inverse spinel structure of the Fe₃O₄ NPs. The presence of iron (Fe) and oxygen (O) in the EDS results confirmed the formation of the magnetite nanoparticles and the presence of carbon (C) and phosphorus (P) on the coated nanoparticles confirmed the successful coating of the Fe₃O₄ NPs. FTIR, NMR, and MS results showed comparable results to those found in the literature.enDissertationUniversity of the Free State