Recent advances on TiO₂ photocatalysis for wastewater degradation: fundamentals, commercial TiO₂ materials, and photocatalytic reactors

The problems of energy resource depletion and the degradation of natural environment are two of the most urgent issues facing modern society. The immense industrialization and rapid population growth have propelled the demand for clean water across the globe. With the growing awareness of environmental protection, researchers and scientists are paying much attention to exploiting and utilizing clean energy, particularly solar energy to resolve both energy- and environmental-related issues. In this regard, photocatalysis has been largely considered as one of the most viable cleanup technologies as the process only requires an inexpensive semiconductor photocatalyst [e.g., titanium dioxide (TiO₂)] and a light source. Therefore the main objective of the book chapter is to introduce readers to this state-of-the-art technology as well as the various commercial TiO₂ photocatalysts developed to date. A brief introduction on the fundamental aspects of photocatalysis and the TiO₂ material will first be presented. This is followed by a review of several commercial TiO₂ photocatalysts (e.g., Degussa P25 and Hombikat UV100), where emphasis will be placed on their applications in water purification and waste degradation. Finally, the latest advancements in the design and development of photocatalytic reactor systems for wastewater treatment will also be discussed. This book chapter is anticipated to provide some insights into the engineering of innovative TiO₂-based materials and reactors for solar energy-driven photocatalysis.