Magnetite nanoparticles as adsorbent material for Cu2+ ions from aqueous solution

Abstract

"Cu2+ ions can cause serious injuries to human health, at both high and low concentrations. Therefore, it is important not only to remove Cu2+ ions from aqueous media, but also to develop analytical methods for their accurate determination at low concentrations. Magnetite is one of the most used sorbents for Cu2+ removal. This work aims at synthesizing magnetite nanoparticles and at evaluating their adsorption capacity toward Cu2+ ions in aqueous solution by means of atomic absorption spectroscopy. Magnetite nanoparticles were characterized by means of a vibrational magnetometer, Fourier transformer infrared spectrum (FTIR), x-ray diffraction (XRD) and Thermal gravimetric analysis (TGA). Magnetic nanoparticles showed Ms values of 52 and 62 emu/g. By taking into consideration the precipitation of Cu(OH)2 as a function of pH in the evaluation of the adsorption capacity of magnetite, we found that the maximum Cu2+ adsorption occurs at pH = 7 and that the adsorption equilibrium of the two samples is reached at 490 and 445 min. The use of blank solution avoids the overestimation of the adsorption capacity due to the presence of insoluble Cu(OH)2. Finally, two models are considered as a liquid/solid phase reaction, pseudo-first- and pseudo-second-order reaction. Batch adsorption kinetics agrees with a pseudo-second-order model, suggesting that chemisorption is the rate-limiting step."