Application of nanoparticles in water and wastewater treatment; challenges and limitations

Increasing demand and shortage of clean water sources due to the rapid development of industrialisation, population growth and long-term droughts have become an issue worldwide. Various contaminants are entering water resources from anthropogenic activities: from conventional pollutants, such as heavy metals and distillates, to emerging micropollutants, such as microcystins and antibiotics. Some of these pollutants could not be removed from water efficiently via conventional water treatment methods. Application of nanomaterials is considered as the fundamental method to more efficient wastewater treatment. Considerable attention was paid to fullerenes (C60), carbon nanotubes, quantum dots, metal oxides such as TiO2, ZnO, Fe2O3, Fe3O4, CuO, CeO2, SiO2 and Al2O3, and nanoparticulate metals such as Au, Ag, Co, and Ni. Among the nanoparticles, titanium dioxide (TiO2) nanoparticles are by far the most extensively studied metal oxide nanoparticles for water treatment. Based on studies, Nanotechnology holds great potential in advancing water and wastewater treatment to improve treatment efficiency as well as to augment water supply through safe use of unconventional water sources.