Síntese, caracterização físico-química e uso de nanopartículas de óxido de zinco para a remoção de alguns metais de águas contaminadas

Abstract

In the state of Minas Gerais (MG), Brazil, the unfortunate natural disasters of Mariana and Brumadinho generated contamination by heavy metals in water effluents. Much research has been carried out to solve this problem and it has been shown that the use of nanoparticulate metal oxides, such as zinc oxide nanoparticles (ZnO-NPs), achieves the removal of some of them. The main objective of this work was to prepare, characterize and use zinc oxide nanoparticles for the removal of metal ions of Al3+, Fe3+, Pb2+ and Mn2+ from polluted waters of the Rio Doce basin and technology prospection. Bibliometric analyses and technological prospecting showed that the beginning of this technology was around 2007 and that today it is considered a growing and promising technology. The results showed that the different methods of obtaining and drying NPs-ZnO influence the reaction yield, the size of the particles and their morphology, in addition, water molecules were identified in their composition, reduced surface areas and oxygen vacancy defects. When the ZnO-NPs were submitted to Rio Doce water samples enriched with all the metals under study, an adsorption of 81% for Fe (III), 40% for Pb (II), 20% for Al (III) and values >0.1% for Mn (II) ions, where only the concentration of Fe (III) ions in solution after the adsorption analysis was below the maximum limits allowed by current regulations. This suggests that the zinc oxide nanoparticles studied can remediate polluted water with high concentrations of Fe (III) metal ions and is a promising material for adsorption of Al (III) and Pb (II) ions.