Selective adsorption of trivalent actinides to activated carbon

Arisaka, Makoto ; Watanabe, Masayuki   ; Kimura, Takaumi 

Adsorption behaviors of trivalent actinides (An(III)) and lanthanides (Ln(III)) to activated carbons with and without oxidation by concentrated nitric acid were investigated. Both An(III) and Ln(III) was adsorbed to activated carbons in the range from pH 1 to 4, and the distribution coefficients ( ) of An(III) and Ln(III) increase with an increase of pH. Activated carbon without oxidation exhibits significant selectivity to An(III) compared with Ln(III). On the other hand, the oxidation to activated carbon deteriorates the selectivity to An(III). The depletion by the oxidation was attributed to the increase of functional groups of oxygen-donor, e.g., carboxyl and/or carbonyl groups because these functional groups are unfavorable for separation between An(III) and Ln(III). The selectivity of activated carbon without oxidation would be attributed to the interaction between -electrons of aromatic ring and the metal ions.