Adsorption behavior of americium on zeolites

Abstract

Zeolites are expected to be used in buffer materials as an admixture to bentonite to increase their ion exchange ability. The behavior of ion exchange adsorption of Am3+ on various zeolites was examined by batch and column methods. The distribution coefficient of Am3+, Kd, increased with equilibrium pH from 1.5 to 4.0. L zeolite and mordenite having large pore size yielded relatively large values of Kd over 103 at pH 3.0. The Kd for L zeolite was unaffected by the concentration of coexisting cations, i.e. Na+ up to 0.1 M, and K+, Ca2+ and Mg2+ less than 0.01 m. The Am3+ ion was not detected in the effluent passed through the L zeolite column up to 90 bed volumes, even when the feed solution contained a relatively large amount of Na+-0.5 m. Americium ion adsorbed on zeolites could be quantitatively eluted with 0.1 m nitric acid. © 1991 Taylor & Francis Group, LLC.