Speaker
Description
The contamination of water resources by toxic mercury (Hg(II)) ions poses a serious threat to ecosystems and human health, necessitating efficient and sustainable remediation strategies. In this study, magnetic CuS/Fe3O4 nanocomposites were synthesized via a green route using castor oil as a renewable solvent and stabilizer. The composites were designed to exploit the strong thiophilic affinity of copper sulfide (CuS) for mercury binding and the magnetic properties of iron oxide (Fe3O4) for easy separation. Fe3O4 nanoparticles were prepared by co-precipitation, followed by solvothermal decomposition of a copper diethyldithiocarbamate precursor in castor oil to form CuS and CuS/Fe3O4 nanocomposites with mass ratios of 1:1, 1:4, and 1:8. Structural and physicochemical characterization (FT-IR, XRD, SEM/EDX, TGA, NMR) confirmed the formation of crystalline nanocomposites with the intended core–shell morphology. SEM analysis revealed that CuS formed spherical nanoparticles, while Fe3O4 appeared as spherical particles with noticeable aggregation, leading to a composite structure with good surface interaction. Batch adsorption experiments revealed that the CuS/Fe3O4 (1:8) composite achieved a high performance, with a maximum adsorption capacity of 295 mg g⁻¹ at pH 8, 20 mg dosage, and 200 min contact time. Kinetic and isotherm modeling indicated that Hg(II) uptake followed a pseudo-second-order model and fit the Langmuir isotherm, suggesting chemisorption on a homogeneous surface. The nanocomposite also exhibited outstanding selectivity, removing Hg(II) quantitatively even in the presence of excess competing ions (Cd2+, Pb2+, Zn2+), and retained ~80 % efficiency after three regeneration cycles. These findings demonstrate that castor oil-mediated synthesis offers a sustainable pathway to highly efficient, selective, and magnetically recoverable CuS/Fe3O4 nanocomposites, highlighting their promise as a scalable, engineering innovation for practical mercury remediation.