Abstract
Nanotechnology has made magnetite nanoparticles (MNPs) significant due to their unique inverse spinel structure (iron ions arranged in a specific geometric pattern), superparamagnetic properties (magnetic only in an external field), and biocompatibility (non-toxic to living tissues). These features enable a wide range of applications, from biomedicine to environmental cleanup. Traditional MNP synthesis relies on high-purity iron salts, which are costly and environmentally burdensome, limiting sustainable, large-scale MNP production. Using acid mine drainage (AMD), which is acidic and rich in dissolved iron and heavy metals, provides an innovative alternative. This work reviews MNP synthesis methods, highlighting co-precipitation for its effectiveness with aqueous iron sources such as AMD. It describes steps to transition from traditional synthesis to hybrid methods utilizing both commercial and AMD-derived Fe3+ and Fe2+. This allows for the direct synthesis of MNPs from AMD, exemplifying a circular economy model. By combining environmental engineering and materials science, this study shows how converting hazardous waste into valuable nanomaterials can reduce pollution and establish a sustainable supply of critical materials.