Abstract
Ph.D. (Chemistry)
The devastating effects of toxic organic pollutants on human health and the environment have necessitated the need to devise holistic techniques for their effective removal from polluted water. Among these pollutants are toxic organic dyes, which are resistant to biodegradation and therefore persist in the environment for a long period of time. These dyes are also resistant to chemical, physical and other conventional methods of water treatment. Although semiconductor photocatalysis is deemed as a holistic method for the judicious eradication of dye pollutants from water, the technology is hindered by some inherent problems including the fact that most of the photocatalysts are active under ultraviolet light (UV) instead of visible light due to their wide band gap. In addition, these photocatalysts have a fast recombination rate of the photogenerated holes and electrons, which are responsible for the photocatalytic degradation process. This research work was therefore designed to modify some selected metal oxide photocatalysts including TiO2, ZrO2, ZnO, Cu2O and ZnS with transition metals, non–metals and multiwalled carbon nanotubes (MWCNTs). It was envisaged that the modified catalysts would possess superior properties over their bare counterparts, overcome their limitation, and possess excellent photocatalytic properties for the effective removal of organic pollutants from water.
Three different methods of synthesis were employed in this work. These include homogeneous co–precipitation, sol–gel, and in situ copolymerisation. All the catalysts synthesised in this work were characterised using X–ray powder diffraction (XRD),..