Synthesis and Characterization of a New Clay Based Magnetic Composite Muscovite/Fe2O3/FTS for Efficient Removal of Toxic Metal Ions

In this study, we developed a magnetic composite using Muscovite which was functionalized with Fe₂O₃ and sodium folate (FTS: C₁₉H₁₈N₇NaO₆) to remove Sm(III), Co(II), and Ni(II) metal ions from wastewater. Various characterization techniques, including X-ray diffraction, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and zeta-sizer devices, were employed to analyze the magnetic composite Muscovite/Fe₂O₃/FTS. After conducting an optimization study of the adsorption operating conditions, we found that the optimum pH for the adsorption of all metals was 6. Isotherm calculations indicated that the langmuir and sips model provided the best fit (with R² ≥ 0.9) for the adsorption of all metal ions. According to the langmuir model, at a pH of 6.0, SD of 1 g L⁻¹, in an adsorbate concentration range of 30 to 300 mg/L, the adsorption capacities of Sm(III), Co(II), and Ni(II) were found to be 40 mg.g⁻¹, 151.4 mg.g⁻¹, and 154 mg.g⁻¹, respectively. It was noted that pseudo 2nd order (PSORE) model was the best fit for the kinetics of adsorption of these three metal ions on the composite with an the average relative errors (ARE) of less than 13% and with a q_max,exp close to q_theoretical. Negative values of ∆G° were obtained at all three temperatures (298, 303, and 313 K), indicated the spontaneity and feasibility of the adsorption processes for Sm(III) and Ni(II) on the magnetic composite. We observed that spontaneity decreased as the temperature increased. We found that nitric acid (HNO₃, 0.5 M) was the most effective eluent, and Muscovite/Fe₂O₃/FTS composite could be reused up to 6 consecutive cycles.