Sorption of144Ce(III) and147Pm(III) on hydrated iron sesquioxide

Study of Colloidal Behavior of 144Ce(III) Based on Centrifugation

“…also more stable and during its centrifugation it is agglomerated to a lesser extent than in the case of trace concentrations. The decrease of the portion separable by the centrifugation with an increasing carrier concentration could also be attributed to forming adsorption radiocolloids [15,16]. The sorption capacity of colloidal impurities randomly present in the solution is relatively low and at higher carrier concentrations a larger portion of ionic forms of the radionuclide will remain non-adsorbed in the solution.-As mentioned above, the presence of this type of radiocolloid is of a less probability.…”

“…The peptization of the colloidal 144 Ce(III) started from 10~3 M CaCl 2 at both pa, from 10" 2 M NaCl at pn 7.0 and from 10" 1 M NaCl at ρχ 9.0. Multivalent cations can in certain cases suppress the "adsorption colloid" formation, because of their competition in the adsorption process [14][15][16], This effect obviously did not occur since, by contrast, up to 10 -3 M CaCl 2 the portion separable by the centrifugation increased and its subsequent decrease can be more probably explained by the above-mentioned peptization action. Thus, particles consisting prevalently of 144 Ce(III)-hydroxide and not foreign particles with a sorbed radionuclide are separated in this case.…”