Chemical Engineering Journal, Vol.181, 387-396, 2012
Eu(III) adsorption using di(2-thylhexly) phosphoric acid-immobilized magnetic GMZ bentonite
In this research, the raw Na-bentonit (S-1) collected from Gaomiaozi County (Inner Mongolia, China) (herein named as GMZ bentonite), was utilized as a support to prepare di(2-thylhexly) phosphoric acid-immobilized magnetic GMZ bentonite (S-3) for the removal of Eu(III) ions from aqueous solution. The adsorption was performed as a function of pH, contact time, temperature and metal ion concentrations in the batch experiments. The results demonstrated that the adsorption was well described by the Langmuir adsorption isotherm with the maximum adsorption capacity of 40.5 mg/g. The kinetic data indicated that the adsorption fit well with the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and exothermic. The recovery could be achieved using a 0.5 M NaCl in 2.0% HCl eluent. The adsorbent was characterized by XRD, SEM, FTIR, Zeta potential and BET. The adsorption mechanism was further confirmed by XPS. (C) 2011 Elsevier B.V. All rights reserved.