Facile fabrication of Fe3O4@Mg(OH)2 magnetic composites and their application in Cu(ii) ion removal

Abstract

In this study, we fabricated magnetic Fe₃O₄@Mg(OH)₂ composites through the seed deposition technique to achieve Cu(II) ion removal from aqueous solutions. As indicated by the characterization results, three-dimensional flower-like spheres composed of external Mg(OH)₂ were formed, with nano-Fe₃O₄ particles uniformly embedded in the “flower petals” of the spheres. The efficacy of Fe₃O₄@Mg(OH)₂-3 in Cu(II) ion removal was examined through batch experiments. The impact of solution pH on removal efficiency was examined, and the pseudo-second-order model and the Langmuir model provided good fits to the adsorption kinetics and isotherm data, respectively. Remarkably, Fe₃O₄@Mg(OH)₂-3 exhibited a significant removal capacity of 1051.65 mg g⁻¹ for Cu(II) ions. Additionally, the composite displayed a notable saturation magnetization value of 17.3 emu g⁻¹, facilitating isolation from sample solutions through external magnetic fields after Cu(II) ion absorption. At the solid–liquid interface, a mechanism involving ion exchange between Mg(II) and Cu(II) cations was realized as the mode of Cu(II) ion removal. The composites' effective adsorption properties and rapid magnetic separation highlighted their suitability for use in treating copper-contaminated water.