Magnetically separable and reusable Fe3O4/rGO photocatalyst synthesized through green approach for heavy metal ion reduction application

The reduction of heavy metal ions in water is essential due to the water demand and human health. The exploration of photocatalytic for heavy metal ions reduction paves a new way. Additionally, the green route synthesis of nanoparticles has gained attention due to environmentally friendly, low-cost, and non-toxic methods. This study investigated the synthesis of Fe₃O₄/rGO nanocomposites utilizing leaves extract and to determine the effect of rGO concentration in Fe₃O₄/rGO nanocomposites on the degradation of hexavalent chromium (Cr(VI)) to be an environmentally friendly trivalent chromium (Cr(III)). Fe₃O₄ nanoparticles were prepared by simple co-precipitation method using Moringa oleifera leaves extract as a natural reducing and captivating agent, while rGO was reduced from GO using Amaranthus viridis leaves extract. Fe₃O₄/rGO nanocomposites exhibit a cubic inverse spinel structure with a crystallite size of approximately 7.4 nm. Fe₃O₄/rGO nanocomposite have imperfect spherical morphology with a particle size of 10.7 nm. The presence of FeO and CC functional groups confirm the presence of Fe₃O₄ and rGO in the nanocomposite which also support by the element composition data. The nanocomposites have superparamagnetic behavior with high saturation magnetization that show strong magnetic response. Under UV irradiation, the photocatalytic process of Cr(VI) achieved a degradation efficiency of 87.5 % for 120 min. The magnetically separable capability allows for easy separation and recycle of the nanocomposites, which was successfully reused three times with high degradation efficiency. The Fe₃O₄/rGO nanocomposites demonstrates potential as a low-cost and green reusable photocatalyst for environmental remediation.