UPTAKE AND RECOVERY OF AMERICIUM AND URANIUM BY ANACYSTIS BIOMASS

The optimum conditions for the uptake of americium and uranium from wastewater solutions by Anacystis nidulans cells, and the recovery of these radionuclides were studied. The optimum pH range for both actinides was in the acidic region between 3.0 and 5.0. In a pH 3.5 solution with an algal biomass of 70 mug/mL, up to 95% of the Am and U were taken up by the cells. However, the uptake levels were lowered considerably when ethylene dinitrilotetraacetic acid (EDTA) or iron or calcium ions were present in the solutions. Most of the radionuclides taken up by the cells could also be desorbed by washing with salt solutions. Of nine salt solutions tested, ammonium carbonate was the most effective. Our experiments using algal biomass to remove radionuclides from wastewaters showed that about 92% of americium and 85% of uranium in wastewater could be taken up by algal biomass from which about 46% of the Am and 82% of the U originally present-in the wastewater could be recovered by elution with a salt solution.