Adsorptive removal of trace uranium ions from simulated wastewater with FeCl_3-modified attapulgite with sodium alginate beads

摘要

The attapulgite (ATP) is a good adsorbent of heavy metal ion due to its high surface area, low cost and environmental compatibility. But the natural ATP has limited adsorption capacity and selectivity. In this study, a cost-effective and ready-generated adsorbent, FeCl3-modified attapulgite (Fe-ATP), was evaluated to remove uranium ions from simulated wastewater. After preparation, Fe-ATP was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscope(SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy(TEM) analysis. The impacts of pH, contact time, ionic strength, temperature and initial U(VI) concentration on the adsorption capacity of Fe-ATP beads were examined. The adsorption kinetics of U(VI) dominated by the pseudo-second order model, and the adsorption isotherms fitted the Freundlich isotherm. The adsorption mechanism involved chemisorption, surface complexation and ions exchange. These results indicate that Fe-ATP bead is a cheap and promising adsorbent for the U(VI) removal and holds potential to be used for radioactive wastewater treatment.