Studies on elimination of nutrients from aqueous effluents using ZnO nanoparticles: the case of ammonium as a model. Experimental and theoretical insights

Abstract

The presence of ammonium (NH4+) in natural waters has increased in the lastyears due to the rising use of agricultural fertilizers, industrial activity and sewage discharges without any decontamination treatment. The great amounts ofthis inorganic cation in water bodies have been considered an environmentalproblem, due to its infuence on the eutrophication process which leads to thedeterioration of water quality. The application of ZnO nanoparticles to assessnutrient elimination, including ammonium, from water bodies has not beenexhaustively studied. In this work, the capability of ZnO nanoparticles to removeammonium cation from aqueous samples induced by adsorption is investigated.In this regards, experiments tending to determine the efciency of nanomaterialshave been performed employing two diferent NH4+ concentrations aiming to replicate two feasible real water-impacted environments. The interactions betweenadsorbent and adsorbate have been explored by employing experimental characterization techniques as well as theoretical DFT simulations. The achieved datademonstrated that the efciency of ZnONPs shows a dependency on the ammonium concentration, ranging between 0.79 and 11.6 mg of ammonium adsorbedper gram of ZnONPs. According to the data on characterization prior and postadsorption of the ZnO nanomaterials the electrostatic interaction would not befavored, being the coordination ones the most feasible as suggested experimentaland DFT results.