Synthesis of core–shell structured Fe 3 O 4 @carboxymethyl cellulose magnetic composite for highly efficient removal of Eu(III)

In this work, a carboxymethyl cellulose (CMC)-modified Fe3O4 (denoted as Fe3O4@CMC) composite was synthesized via a simple co-precipitation approach. Fourier transform infrared spectroscopy, zeta potential and thermogravimetric analysis results indicated that CMC was successfully coated on the Fe3O4 surfaces with a weight percent of ~30 % (w/w). The prepared Fe3O4@CMC composite was stable in acidic solution and could be easily collected with the aid of an external magnet. A batch technique was adopted to check the ability of the Fe3O4@CMC composite to remove Eu(III) as a function of various environmental parameters such as contact time, solution pH, ionic strength, solid content and temperature. The sorption kinetics process achieved equilibrium within a contact time of 7 h. The sorption isotherms were well simulated by the Langmuir model, and the maximum sorption capacity at 293 K was calculated to be 2.78 × 10−4 mol/g, being higher than the series of adsorbent materials reported to date. The ionic strength-independent sorption behaviors, desorption experiments by using ammonium acetate and disodium ethylenediamine tetraacetate as well as the spectroscopic characterization suggested that Eu(III) was sequestrated on the hydroxyl and carboxyl sites of Fe3O4@CMC via inner-sphere complexation. Overall, the Fe3O4@CMC composite could be utilized as a cost-effective adsorbent for the removal of trivalent lanthanide/actinides (e.g., 152+154Eu, 241Am and 244Cm) from radioactive wastewater.