Sonochemistry production of ZnO and zero-valent Fe nanoparticles from solutions of electric arc furnace dust leaching

In this work, nanoparticles of ZnO and zerovalent Fe were sonochemically synthesised using a solution produced from electric arc furnace dust leaching as raw material. The leaching was previously carried out using ultrasound with various concentrations of sulphuric acid. The resulting solutions contained, in addition to varying amounts of Zn and Fe, elements such as Cr, Mn, Mg, Ca, and Si. Two methods were developed, one for Fe and one for ZnO, to obtain the nanoparticles and to avoid the precipitation of the additional elements during the nanoparticle production. The synthesis of ZnO nanoparticles was performed through the formation of a precursor by sonochemical reaction with NaOH, and the thermal decomposition of this precursor by heating in furnace. The production of Fe nanoparticles involved the precipitation of FeOOH, the dissolution of FeOOH in HCl solution, and the ultrasound-assisted reduction of the iron ions with NaBH4. The nanoparticles were characterised by scanning and transmission electron microscopy, X-ray diffraction, X-ray fluorescence, and UV spectroscopy. The nanoparticles of Fe had a particle size of 6 nm and resulted in zerovalent Fe, whereas the ZnO nanoparticles were between 30 and 50 nm.