Síntese e caracterização do pentóxido de nióbio pela metodologia de pechini modificada e estudo preliminar na adsorção de poluentes

Abstract

The presence of emerging pollutants in wastewater demands efficient materials for their removal. Niobium pentoxide (Nb₂O₅) emerges as a promising alternative due to its stability and synthesis possibilities. In this study, Nb₂O₅ was synthesized using the Pechini method, replacing ethylene glycol with the surfactant Tween-80 to evaluate the impacts on morphology, structure, and performance in removing methylene blue dye. Thermal characterization (TGA) indicated that the temperatures were sufficient for the complete decomposition of the precursors, with greater thermal stability in the route with Tween-80. SEM micrographs revealed distinct morphologies: while the material obtained with ethylene glycol exhibited a smooth surface, the one synthesized with surfactant presented circular fissures, conferring greater roughness. BET analysis confirmed the morphological modification, with an increase in surface area from 0.3076 m²/g (ethylene glycol) to 1.26 m²/g (Tween-80). In turn, XRD analysis showed that both routes resulted in the same orthorhombic crystalline phase (T-Nb₂O₅). Finally, adsorption tests with Methylene Blue showed high efficiency of the material for dye removal, reaching approximately 91% for Nb₂O₅ obtained with ethylene glycol and 93% for that synthesized with Tween-80, reinforcing the potential of the alternative route as a promising strategy for environmental applications.