Modification of natural bentonite using a chelating agent for sorption of 60Co radionuclide from aqueous solution

Chemisorption of Co-60 radionuclide from aqueous solution using modified bentonite clay with 8-Hydroxy quinoline, as a chelating agent, was investigated. Characterization of the modified clay was carried out using some analytical techniques including, SEM, XRF, EDX and FT-IR spectroscopy. Some factors affecting on the sorption process were studied such as pH of medium, contact time, metal ion concentrations and temperature. Some kinetic models were tested for the sorption process including pseudo-first-order, pseudo-second-order, intraparticle diffusion and Boyd's film-diffusion model. The results indicated that the sorption process well fit pseudo-second-order model, the sorption is controlled by intra-particle diffusion mechanism, and the process is chemisorption since the value of diffusion coefficient is in the order 10(-15) m(2)/s. Regeneration process was carried out, the results illustrated that 8HQ-Bent can be completely generated with 0.5 M HNO3. Finally, one can conclude that the modified bentonite is an efficient sorbent media and recommended for removal of Co-60 radionuclide from radioactive waste. (C) 2016 Elsevier B.V. All rights reserved.