Nanoparticles of FeNbO₄ Produced by Microwave Assisted Combustion Reaction: A Potential Technology for the Treatment of Wastewater

Abstract

Iron(III) niobate, FeNbO₄, was synthesized for the first time by microwave-assisted combustion reaction between Fe(NO₃)₃.9H₂O and NH₄[NbO(C₂O₄)₂(H₂O)₂](H₂O) in the presence of NH₄NO₃ and Urea {O=C(NH₂)₂}. Experiments of X-ray powder diffraction revealed a small crystallite size for this material, 16 nm, and the results of MEV showed that it forms agglomerates with diameters between 80 and 180 nm with spherical shapes. HRTEM images revealed that the material is formed by clusters of particles with a diameter near 20 nm. A surface area of 40 m²g^-1 was determined by experiments of specific surface area (SSA). The FeNbO₄ induced the decomposition of H₂O₂, forming radicals that, in turn, discoloured Indigo dye Carmine (IC) a solution. The results showed that this niobate was able to degrade 55% of the initial solution in the presence of H₂O₂ after 360 minutes of reaction time.

Keywords:
iron(III) niobate; synthesis by microwave-assisted combustion; advanced oxidative processes; environmental remediation; organic contaminants