Removal of UO22+ ions from simulated wastewater onto Romanian aluminium pillared clays

The aim of the present study is to investigate the removal of UO22+ ions, at room temperature, onto different types of Romanian clays: raw and modified Al-pillared samples, in order to determine their potential uses. The results indicate that the adsorption of UO22+ ions from aqueous solution depends on concentration of uranium in simulated wastewater, on contact time and on the ratio of sorbent/solution value. The Al-pillared clay samples have a higher sorption capacity compared with Na-form clay samples. The very good results are obtained using Al-pillared clay of Razoare areal, when the equilibrium is attained after 4 days and the uranium sorption of 80% and K of 200 value were reached. The depletion of the uranium uptake at higher initial solution concentration (C > 0.5 mg/mL) is probably attributed to the surface precipitation processes, which produce the blockage of micropores and disturb the ion process evolution. The obtained results underline the possibility of Romanian modified clays to be used for the treatment of radioactive liquid waste containing UO22+ ions.