Abstract

Nowadays, there has been a continuously increasing amount of research and development in the area of photochemistry (both heterogeneous and homogeneous) as it becomes an alternative technology for water/wastewater treatment. In this context, homogeneous photo-Fenton reaction and heterogeneous TiO₂ photocatalysis are reviewed as they are considered a highly competitive water treatment technology among the advanced oxidation processes (AOPs) for the removal of toxic organic pollutants not treatable by conventional techniques due to high chemical stability and/or low biodegradability. Many toxic substances such as phenol and phenolic compounds, pesticides, and pharmaceuticals are successfully destroyed by these technologies. This entry reviews fundamentals and mechanism, operating parameters, and the applications in water/wastewater treatment. The entry also summarizes the optimum conditions in treating each toxic chemical by photo-Fenton and TiO₂ photocatalysis. The next challenge in technology development is included as well.