Abstract
M.Sc. (Nanoscience)
Environmental contamination by emerging organic pollutants such as pharmaceuticals has become a great concern due to their health effects on the fauna and flora. Pharmaceutical products such as antibiotics (namely cinoxacin, enoxacin, enrofloxacin, ciproxacin, danofloxacin and amoxicillin, among others) have been extensively used for the treatment of bacterial infections as well as stimulating the growth of livestock. Therefore, due to their increasing demand, they have become emerging environmental pollutants that have been found in soil, surface water, groundwater, wastewater sediment and aquatic plants. Even though the concentrations of antibiotics in the aquatic environment are generally present at trace levels, they can lead to severe human health effects and ecosystems. Therefore, there is a necessity to expand fast, simpler and cost-effective methods for the removal of antibiotics. In view of the above, the aim of proposed study focuses on the synthesis/preparation of carbon-based nanocomposite to address some critical issues for the treatment of emerging pollutants, especially antibiotics in aqueous solutions and wastewater systems.
The first part of this proposed study discusses the synthesis, characterizations and application of V2O5-ZnO coated carbon nanofibers (V2O5-ZnO@CNF) nanocomposite that served as a suitable material for adsorptive removal of selected fluoroquinolone antibiotics such as ciprofloxacin (CIPRO) and cinoxacin (CINO) from aqueous solutions. The effect of different parameters on the adsorption capacity or efficiency such as sample pH, the mass of adsorbent and contact time was investigated using response surface methodology based on Box- Behnken design. The adsorption mechanism was investigated using isotherm (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Flory-Huggins ) and kinetics models (pseudo first and second order). Experimental data were fitted well with Langmuir isotherm and pseudo-second-order kinetic models. This implied that the adsorption process was homogenous and dominated by chemisorption process as the rate-limiting mechanism through sharing or exchange of electrons between adsorbent and CIPRO or CINO. In addition, the intraparticle diffusion model demonstrated that the adsorption process followed two stages.
The second part of the study investigated the application of ZnO@CNF nanocomposites for the removal of amoxicillin (AMX) in aqueous and wastewater samples. The adsorption process was investigated using equilibrium adsorption isotherms and kinetics. Three isotherm models were investigated and the experimental data were best by Langmuir...