Preparação, caracterização físico-química e avaliação de nanoferritas-nióbio magnéticas para remoção de metais de águas superficiais e prospecção tecnológica

Abstract

Magnetic nanoparticles (MNPs) have received special interest due a wide range of technological applications, including efficient and low-cost magnetic nanoadsorbents for the removal of contaminating metals in water. In the present work, nanoferrites and niobium nanoferrites were synthesized by co-precipitation method, characterized, and evaluated as nanoadsorbent materials in the removal of Pb+2, Fe+3, Al+3, Mn+2 metal ions from aqueous solutions and under real-world conditions with water from the Rio Doce. The use of niobium ferrite nanoparticles in metal removal applications in water were compared to other magnetic nanoadsorbents to assess the maturity of the technology, and it was discovered that the nanomaterial lacks technological maturity, nevertheless the novelty of the material is metal removal in water. To characterize the nanoparticles, researchers used FTIR, DRS, size and zeta potential measurements, total reflection X-ray fluorescence - TXRF, Raman spectroscopy, X-ray diffraction, thermogravimetry, transmission and scanning microscopy TEM and SEM, magnetization measurements, electron paramagnetic resonance spectroscopy - EPR, Mössbauer spectroscopy, and nitrogen gas adsorption analysis. The findings revealed magnetic particles with nanometric dimensions, variable spherical morphologies with diameters ranging from 3 to 20 nm, and superparamagnetic behavior at room temperature. The aggregation of nanoparticles was reduced when they were coated with citrate and β-cyclodextrin. The metal adsorption results showed that 100% of Pb+2 ions and 63% of two Fe+3 ions were removed in aqueous solution, The proof of concept using Rio Doce water demonstrate the removal of 74.8% of Mn+2 ions and 38.9% of Pb+2 ions. According to the result of this research, niobium nanoferrites have significant technological potential as a high efficiency nanoadsorbent magnetic material for removing ions such as Pb+2, Fe+3, and Mn+2 from contaminated water.