The kinetic and thermodynamic adsorption of Eu(III) on synthetic maghemite

In this study, maghemite (gamma-Fe2O3) nanoparticles were synthesized by calcining limonite under H-2 atmosphere. The adsorption of Eu(III) on maghemite was studied by batch experiments under various experimental conditions. The kinetic adsorption processes were well described by pseudo-second-order model with high correlation coefficient. The macroscopic results showed that the adsorption of Eu(III) on maghemite significantly decreased with increasing ionic strength, indicating that outer-sphere surface complexation predominated their adsorption of Eu(III). The adsorption isotherms indicated that the removal of Eu(III) adsorption on maghemite were fitted by Freundlish models better than Langmuir and D-R models. The calculated thermodynamic parameters showed that the adsorption of Eu(III) on maghemite was a spontaneous and endothermic process. According to XPS analysis, the high effective adsorption of Eu(III) was mainly attributed to oxygen-containing functional groups of maghemite. (C) 2016 Elsevier B.V. All rights reserved.