Immobilization of uranyl ions from dilute solutions by contact with ultrabasic and basic rocks

Immobilization of uranyl ions from 0.01 M NaCl and NaHCO3 solutions with Fe(II)-rich samples of ultrabasic (dunite) and basic (olivine gabbro, gabbronorite) rocks was studied. From NaCl solutions, uranium is removed to approximately equal extent with all the samples, whereas with NaHCO 3 the immobilization efficiency differs by a factor of several units, being directly dependent on the FeO content. Uptake of large amounts of U (0.13-0.16 μmol g-1 from solutions initially containing 9 μM UO 2 2+) from NaHCO3 solutions, even at high pH values (9.0), make dunite and olivine gabbro promising as materials for making artificial geochemical barriers for dissolved uranium. © 2013 Pleiades Publishing, Ltd.