Recent developments in the use of metal oxides for photocatalytic degradation of pharmaceutical pollutants in water—a review

In recent years, metal oxide semiconductors have been explored as photocatalysts for the degradation of organic contaminants in water/wastewater. The uniqueness of these oxide materials is in their ability to harness energy in the UV/Vis range, their relative ease of synthesis, low cost, and their general high surface ratio to mass, etc. Thus, these materials have consequently drawn much profound interest in environment applications, particularly pharmaceutical drugs for photocatalytic degradation. Furthermore, the non-toxic nature of most metal oxide semiconductors means they are convenient for water treatment works, resulting in safe drinking water for humans and safe environments for aquatic mammals. Pharmaceuticals are emerging pollutants that are increasingly being found in water systems. They have been detrimental to the human and animal health. In this article, pharmaceutical drugs abatement from water via photocatalysis process using oxide-based advanced metals such as TiO₂, ZnO, Fe₂O₃,WO₃, and Bi₂WO₆ is discussed. Degradation of various drugs at laboratory scale have been assessed and examples cited. Various approaches to metal oxides modifications and synthesis methods to improve degradation efficiency have also been discussed. Effects of experimental/operational parameters in the degradation process have been compiled and compared. Finally, a short preview of degradation of pharmaceuticals pilot scales is also highlighted.