Application of Zinc Ferrite Nanoparticles for the Magnetic Removal of Algae That Bind Cadmium

The removal of cadmium from contaminated water remains a critical challenge due to its high toxicity, persistence, and limited treatability at low concentrations. In this study, we propose a novel algal-nanoparticle system that integrates cadmium adsorption by <i>Chlorella vulgaris</i> with zinc ferrite (ZnFe₂O₄) nanoparticle-assisted sedimentation, with the aim of addressing a significant operational challenge in algal remediation. The microalgal biomass demonstrated the capacity to remove cadmium with efficiencies exceeding 90%, facilitated by adsorption through surface functional groups. The incorporation of ZnFe₂O₄ nanoparticles promoted the formation of dense, magnetically responsive aggregates, significantly accelerating biomass settling without the necessity for additional chemical flocculants. The strategy's efficacy is evidenced by its enhancement of metal removal and solid-liquid separation processes, which renders it a potentially scalable and environmentally sustainable approach for the treatment of cadmium-contaminated wastewater. The strategy holds relevance for effluents derived from mining, electroplating, fertilizer production and battery manufacturing.