UV and Visible Light Active Nanostructure Photocatalysts for Disinfection and Decomposition of Biohazards

Abstract

Rapid disinfection and effective removal of biohazards from water is important and necessary for safeguarding water, due to availing public health and environmental concerns. To achieve this aim, many techniques such as ultraviolet, chlorination, ultrasonic and ozone have been widely investigated and employed, though there are many drawbacks in these methods which are becoming more problematic in the developing world. In recent decades, two advanced oxidation techniques, photocatalysis (PC) and photoelectrocatalysis (PEC), have drawn extensive attentions, as they have displayed great potentials to be more sustainable, affordable, safer and robust for water purification technologies. There are still many issues however need to be solved, such as the identification of reaction intermediates, development of rate expressions and the photocatalytic efficiencies of the photocatalysts are still far from satisfaction. Therefore, it is necessary to develop high efficiency photocatalysts and study the fundamental mechanisms in the PC and PEC processes. In this thesis, three types of UV and/or visible light active nanostructured TiO2 films with different structures and crystal phases have been developed, the fundamental aspects such as the electron transport properties in the photocatalyst films have been studied in detail, and the disinfection and decomposition performances of the obtained photocatalysts against Escherichia coli (E. coli) bacteria have been investigated. To achieve these objectives, systematic studies have been performed including the establishment of experimental methodology, characterisations of nanomaterials, performance evaluation and mechanistic aspects.