Effective removal of Zn (II) ions from aqueous solution by the magnetic MnFe2O4 and CoFe2O4 spinel ferrite nanoparticles with focuses on synthesis,characterization, adsorption,and desorption

In this study, the MnFe₂O₄ and CoFe₂O₄ spinel ferrites nanoparticles were synthesized via a practical co-precipitation route to investigate the zinc removal from aqueous solution. The synthesized magnetic adsorbents were characterized by XRD, VSM, FE-SEM, BET, EDS, and DLS analyses. The synthesized adsorbents had a diameter range of 20–80 nm. The specific surface areas of adsorbents were found to be 84.5 and 50.4 m²/g for MnFe₂O₄ and CoFe₂O₄, and the saturation magnetization were 61.39 and 37.54 emu/g, respectively. The effects of initial pH, contact time, metal ion concentration, and temperature on Zn (II) adsorption were precisely investigated. These nanoparticles could remove Zn (II) by following the Langmuir isotherm model at optimum pH = 6, with the high adsorption capacities of 454.5 and 384.6 mg/g for MnFe₂O₄ and CoFe₂O₄, respectively. The results of kinetics studies were well fitted by pseudo-second-order, with the determination coefficients of 0.999 for both adsorbents. The thermodynamics studies showed that the zinc (II) adsorption was an exothermic and spontaneous process. Furthermore, the reusability and the desorption capability of adsorbents were also investigated.