Synthesis and Characterization of Iron-Zinc-Aluminum Mixed Metallic Oxide from Metal Scraps Focusing on Its Application in Antifungal Paints

Abstract

The use of sustainable multifunctional pigments obtained from secondary raw materials has been identified as an effective strategy to improve the performance of environmentally friendly protective coatings. In this study, Fe-Zn-Al oxide nanoparticles were obtained from metal waste electrochemically and used as an antifungal pigment in aqueous paints. Scrap metal, galvanized steel, aluminum and zinc were dissolved and electrochemically filtered, calcined at 700 °C and ball milled to obtain mixed metal oxide nanoparticles. These pigments were analyzed by XRD, FESEM-EDS, FTIR and UV-Visible spectroscopy. XRD results demonstrated that Fe-Zn-Al mixed metal oxides with hematite structure were formed with highly crystalline nanoparticles, while FESEM-EDS results proved uniform distribution of Fe, Zn, Al and O elements. Formation of metal-oxygen bonds was confirmed by FTIR spectroscopy whereas UV-Vis absorption spectra were found to be broad for mixed metal oxides with defects. Antifungal activity was evaluated against Penicillium, Aspergillus niger, Aspergillus fumigatus and Rhizopus sp. using diffusion techniques in agar wells and gravimetric reduction of biomass. It is clear that these nanoparticles had antifungal activity in a dose-dependent manner with greater activity against Penicillium and Rhizopus sp. These findings suggest that electrochemically synthesized Fe-Zn-Al mixed metal oxide nanoparticles derived from waste material are suitable for use as environmental friendly multi-functional pigments for antifungal water-based paints.