In-situ preparation of lignin/Fe₃O₄ magnetic spheres as bifunctional material for the efficient removal of metal ions and methylene blue

In this paper, magnetic composite of lignin/Fe₃O₄ spheres were synthesized via a straightforward one-step in-situ solvothermal method showing good capacity for adsorbing heavy metal ions and dyes. The physicochemical properties of lignin/Fe₃O₄ spheres are analyzed using a range of techniques such as SEM, XRD, FTIR, VSM, TG, and BET. Lignin/Fe₃O₄ spheres exhibited high adsorption capacities of 100.00, 353.36 and 223.71 and 180.18 mg/g for Cu (II), Ni (II) and Cr (VI) metal ions and methylene blue (MB) with equilibrium attained within 60 min. After the recycling experiments, lignin/Fe₃O₄ spheres still possesses excellent superparamagnetic properties and displays high adsorption capacity. The lignin/Fe₃O₄ spheres are an efficient and continuous adsorbent to remove heavy metal ions of Cu (II), Ni (II), Cr (VI) and cationic dyes of methylene blue in wastewater, which proves the great potential in practical pollutants treatment applications for water systems.