Green Photocatalysis for Degradation of Organic Contaminants: A Review

Many organic pesticides that were banned a few decades ago, as well as those that are currently in use in many parts of the world, pose some serious threat to human life and the ecosystem because of their persistent and bioaccumulative nature. In the recent years advanced oxidation technology has been widely employed in water treatment for elimination of resistant organics. An actively researched green chemistry approach to treat recalcitrant and harmful organic priority pollutants is titanium dioxide mediated photocatalysis. A number of recent studies have focused on enhancing the photocatalytic degradation efficiency of TiO2 using various approaches such as doping with metals and non-metals, formation of composites with polymers and bonding with suitable clays. Many researchers have conducted studies to predict the optimal conditions required to obtain maximum photocatalytic rates. Also, the ability to operate this technology using solar irradiation at ambient temperatures makes it an economically favorable option. This review summarizes the recent advances in the area of TiO2/UV mediated photocatalysis for degradation of persistent pollutants and discusses possible mechanisms of mineralization for various contaminants.