Cost‐Effective Eco‐Friendly Synthesis of Magnetite Nanoparticles From Tuna Fish Waste Cans as a Precursor for Magnetic Polymer Fabrication

This research outlines a sustainable methodology for converting discarded tuna cans into functional magnetite nanoparticles (Fe 3 O 4 ) with a yield of 34%. The process utilizes a straightforward and cost‐effective calcination technique. Characterization techniques such as x‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) confirmed that the obtained nanoparticles possessed the structural properties consistent with magnetite. These nanoparticles were then employed as solid stabilizers in Pickering emulsion polymerization of styrene, effectively replacing conventional surfactants. The resulting oil‐in‐water (O/W) emulsions exhibited stability and magnetic responsiveness over a range of Fe 3 O 4 concentrations (0.5–4.0 wt%). Free‐radical polymerization yielded spherical polystyrene/Fe 3 O 4 composite microparticles, as evidenced by SEM and energy‐dispersive x‐ray spectroscopy (EDX). FTIR analysis further confirmed the coexistence of polymer and magnetite phases within these composites. Vibrating sample magnetometry (VSM) revealed ferromagnetic behavior with a saturation magnetization of 0.19278 emu/g. This innovative approach, transforming metal waste into valuable composite materials, exemplifies advancements in green nanotechnology. The resulting polystyrene/Fe 3 O 4 composites hold promising applications in targeted drug delivery, environmental remediation, and magnetic sensing. Furthermore, this strategy aligns with the principles of a circular economy by valorizing industrial waste.