Amine-Terminated Modified Succinic Acid-Magnetite Nanoparticles for Effective Removal of Malachite Green Dye from Aqueous Environment

In this study, amine-terminated succinic acid-modified magnetic nanoparticles (MSA@TEPA) have been successfully synthesized using a facile two-step procedure as a new effective adsorbent for the removal of malachite green from aqueous solutions. The MSA@TEPA was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), zeta potential, thermal gravimetric analysis (TGA), and X-ray diffraction (XRD) analysis. The parameters influencing the adsorption capacity of MSA@TEPA, such as pH (3–8), contact time (t: 5–480 min), initial concentrations of MG dye (Co: 20–200 mg/L), and adsorbent mass (0.05–0.5 g), were evaluated. It was observed that, under specified experimental conditions (Co: 25 mg/L, pH: 7.1, T: 298 K, agitation rate: 100 rpm, and t: 420 min), the MSA@TEPA nanocomposite exhibits excellent adsorption efficiency (97.74%) for MG dye. The adsorption kinetics follow the PSO model, and the equilibrium data were fitted to the Langmuir isotherm with a maximum adsorption capacity of up to 282.65 mg/g. The thermodynamic parameters indicated that the adsorption process of MG dye was an exothermic process. After five consecutive cycles, MSA@TEPA nanocomposite still show good adsorption efficiency for MG dye. It is assumed that, because of the presence of amine group, adsorption mainly occurred through electrostatic interaction and H-bonding. In conclusion, the study shows a new and effective adsorbent with high adsorptive capacity, easy magnetic separation using an external magnetic field, and reusability for MG dye elimination from aqueous solutions.