Nickel nano particles; spent catalyst; chemical reduction; recovery

controlling nitrate transfer toward water resources and reducing its concentration is essential to protect human health and the environment. Recently, the use of different technologies to remove these contaminants is investigated. In this study, different carbon nanostructured such as, carbon nanofibers (CNFs) and carbon nanotubes (CNTs) grown on a activated carbon, carbon nanocomposites, graphene oxide, carbon dots, and graphene quantum dots were produced. The samples were characterized using a scanning electron microscopy (SEM), transmission electron microscopy (TEM) and varied analytical methods. Based on the results, Of the variety of adsorbents available for the removal of nitrate from drinking water, the best nitrate removal capacity is achieved using carbon nanofibers (CNFs) and carbon nanotubes (CNTs) grown on a activated carbon. The effects of nitrate concentration, pH, and etc, on the adsorption process were investigated. 90% nitrate removal was obtained at pH=7 and nitrate concentration = 100 mg/l.