The use of seeded ultrafiltration for the removal of some radionuclides

The use of seeded ultrafiltration for the treatment of waste streams arising from the nuclear research activities of the developing countries has demonstrated its high potential as an efficient process for the removal of radionuclides present in the rad waste stream. The results also show that the proper choice of absorbers can reduce the radioactivity levels to below the authorised discharge limits of most of these radionuclides. Decontamination factors (D F) for the system using titanium hydroxide (HTiO) absorber are in the order of 10 at PH 7. The combined effect of (HTiO) and preformed nickel hexacyanoferrate(II) (NiFCN) gave higher DFs of about 40 for Hg-203 and Cs-137, about 300 for Zn-65 but less than 10 for Co-60. The use of NiFCN prepared in-situ improved the D F, of Co-60 (higher than 300), while D F for Cs-137 was slightly reduced to about 30. The highest DFs for nearly all the radionuclides under investigation was achieved by using a combination of NiFCN prepared in-situ and NiFCN slurry. Key words: Decontamination, Co-60, Zn-65, Sr-90, Cd-109, Cs-137 and Hg-203, inorganic absorbers, ultrafiltration.1 fig., 1 tab