Immobilization of divalent transition metals from aqueous solutions using crystalline hydrated titania fibers

Abstract

From a viewpoint of the treatment of high level radioactive liquid waste , the immobilization of divalent transition metal ions from aqueous solutions was studied by the use of the crystalline hydrated titania (H2Ti2O5• nH2O) fibers as an ion-adsorbent . The each metal ion was saturately adsorbed on the fibrous adsorbent from the aqueous solution of the divalent transition metal acetate. The adsorbed metal ions were immobilized in crystal lattices as main components of various titanate minerals after the sintering treatment. The copper ions were immobilized into the mineral assemblage of rutile, and Cu2TiO3 and Cu3TiO4 phases having a complex crystal structure . Zinc ions were fixed into the mineral assemblage of rutile and a Zn2TiO4 phase of the inverse spinel structure. Each metal ion of manganese, cobalt and nickel was immobilized into the same mineral assemblage of rutile and a MTiO3 (M=Mn, Co, and Ni) phase of the ilmenite structure . Rutile in these immobilizers occurs as a matrix mineral in the largest amount. The leachability of each metal ion in the immobilizers was measured under normal atmospheric and hydrothermal conditions . The results of the former indicated to be very stable with high leach resistance of maximal 3.210-9 gcmd-1 of mangnese ion, and the results of the latter also indicated to be very stable with maximal 9.1109g• cm2d-1 of nickel ion. [Received September 13, 1984]