Carbonaceous NiFe₂O₄ Nanocomposite: An Efficient Nano-Adsorbent for Toxic Metal Removal from Aqueous Solutions

This study explores the potential of a novel carbon-coated NiFe₂O₄ nanocomposite as an efficient nano-adsorbent for Pb(II) and Cd(II) removal from aqueous solutions. The single-step synthesis combines the advantageous properties of NiFe₂O₄ and carbon coating. Characterization techniques, including XRD, Raman, FT-IR, FESEM, and TEM, revealed a high carbon content (53%) and a crystallite size of 36 nm. Optimization of adsorption parameters (pH, dosage, contact time) was performed using central composite design (CCD) under response surface methodology (RSM). At acidic pH, the nano-adsorbent achieved removal efficiencies of 97.6% for Pb(II) and 99.5% for Cd(II). Adsorption data followed the Freundlich isotherm and pseudo-second-order kinetic models, indicating significant chemisorption. The adsorption capacities were 497.7 mg/g for Cd(II) and 325.6 mg/g for Pb(II). The NiFe₂O₄/C nanocomposite also demonstrated multiple reuses without significant efficiency loss.