Tin dioxide as a photocatalyst for water treatment: A review

Many phenols, phthalates and other toxins are released into the environment from industrial or agricultural processes, or household waste. These compounds are often stable and difficult to degrade in wastewater facilities, thus posing a serious long-time risk. The development of novel and efficient technologies for the environmentally sustainable removal of these dangerous compounds from different sources is of crucial importance. The photocatalytic oxidation of organic pollutants in the presence of semiconductors such as tin(IV) oxide (SnO₂) is a green technology and seems to be a highly promising technique for water treatment and for the removal of recalcitrant compounds. The photocatalytic efficiency of SnO₂can be enhanced via modifications in the design of the metal oxide, resulting in a lower recombination rate of electron–hole pairs and an increase in the efficiency of the semiconductor during the excitation state, which allows the degradation process of toxins to proceed under UV or visible light irradiation. This review article summarizes some of the most relevant investigations and fundamental aspects related to SnO₂and its activity and discusses recent achievements in the modification of SnO₂as a photocatalyst for phenol degradation.