An Innovative Bioremediation Approach to Heavy Metal Removal: Combined Application of <em>Chlorella </em><em>vulgaris </em>and amin functionalized MgFe₂O₄ Nanoparticles in Industrial Wastewater Treatment

The removal of heavy metals from industrial wastewater remains a major environmental challenge, demanding efficient, sustainable solutions. This study explores the combined use of Chlorella vulgaris and amine-functionalized magnesium ferrite (MgFe₂O₄-NH2) nanoparticles to remove cobalt ions from battery effluents. The research aims to explore the capacity of C. vulgaris to adsorb heavy metals, followed by their separation using magnetic nanoparticles. Cobalt adsorption by C. vulgaris was facilitated through the in-teraction of metal ions on the cell wall, achieving a removal efficiency of 96.44% within 30 minutes, which increased to 98.78% over 10 hours. Amine-functionalized MgFe₂O₄ nano-particles, synthesized and characterized using HRTEM, FTIR, and VSM, displayed high surface reactivity due to the presence of -NH₂ and -OH groups. At neutral pH, zeta poten-tial measurements revealed a slightly negative charge (-5.6 ± 4.3 mV), while protonation at lower pH levels enhanced electrostatic interactions with the negatively charged algal bi-omass. Magnetic separation of the cobalt-adsorbed biomass achieved efficiencies ranging from 94.9% to 99.2% within 60 seconds, significantly outperforming conventional sedi-mentation methods. SEM and FTIR analyses confirmed the binding of nanoparticles to algal cell walls. The even distribution of MgFe₂O₄ nanoparticles on algal surfaces was further validated by TEM imaging, and the strong magnetic properties of the nanoparticles enabled rapid and efficient separation under an external magnetic field.