ADVANCED MAGNETIC FERRITE NANO ADSORBENT FOR COPPER (II) REMOVAL: ROLE OF LANTHANUM DOPING

Abstract

The adsorption behaviour of copper(II) ions on lanthanum-doped cobalt ferrite (La–CoFe₂O₄) nanoparticles in acidic and basic aqueous media. The adsorbent was synthesized using an appropriate chemical method and characterized by techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer–Emmett Teller (BET) surface area analysis to confirm its crystal structure, morphology, elemental composition, and surface characteristics. Batch adsorption experiments were carried out to evaluate the effects of solution pH, contact time, initial copper ion concentration, adsorbent dosage, and temperature on the adsorption efficiency. The adsorption experiments were conducted to evaluate the influence of solution pH, contact time, adsorbent dosage, initial copper ion concentration, and temperature on the adsorption process. The adsorption efficiency was strongly dependent on the pH of the solution. Under acidic conditions, the adsorption of Cu(II) ions was suppressed due to protonation of the adsorbent surface and competition from hydrogen ions for active adsorption sites. In contrast, adsorption was significantly enhanced in basic medium because of increased surface deprotonation and stronger electrostatic interactions between Cu(II) ions and the negatively charged adsorbent surface. Equilibrium data were found to fit the Langmuir adsorption isotherm, indicating monolayer adsorption, while the kinetic results were consistent with the pseudo-second-order model, suggesting that chemical interactions play a significant role in the adsorption mechanism. The magnetic nature of the adsorbent enabled rapid separation from the treated solution without secondary pollution. The findings demonstrate that lanthanum doping effectively improves the adsorption performance of cobalt ferrite toward copper ions, particularly under alkaline conditions. Owing to its high adsorption efficiency, reusability, and ease of magnetic recovery, lanthanum-doped cobalt ferrite is a promising material for the sustainable removal of heavy metals from industrial wastewater.