Acid Mine Drainage Treatment using Maghemite Nanoparticles

The invention relates to the use of maghemite nanoparticles at pH < 5 to remove sulphate, manganese, copper, nickel, cobalt and zinc metal ions from acid mine drainage (AMD). In a conventional way of AMD treatment, these pollutants are only removed at higher pH and requires costly alkaline chemicals to remove. The only metals which are known to precipitate at low pH are Iron (III) and Aluminium (III). The pH of AMD is extremely low and in order to effectively achieve almost complete removal of the pollutants, method optimization is required. Relative to the conventional way of treatment, adsorption is highly convenient, cost-effective and considered to be a noble process. For this invention, a combination of adsorption and precipitation processes have been employed to achieve high metal and sulphate removal. The corresponding removal percentages of pollutants achieved in a study were sulphate (89%), manganese (79%), cobalt and zinc (98%), Nickel (96%) and copper (100%). Overall, the employed method makes use of fewer chemicals to remediate acid mine drainage pollution under cost-effective scenarios, while also the possibility exists for recovering valuable resource from AMD.