Separation
of radionuclides in trace concentrations by cellulose acetate membranes has been under investigation in this laboratory, and the behaviour of some important radionuclides such as 13'Cs and % under reverse osmosis has been reported earlier. The present work deals with a few other typical radionuclides such as 6oCo, '03Ru and ')'I which are not fully amenable to conventional methods for their removal. Separation of these radionuclides from liquid streams by the reverse osmosis process was studied using a small reverse osmosis test cell. Various parameters like membrane porosity, applied pressure and feed activity levels were investigated.
Cellulose acetate membranes offer reasonable separation of "Co, r"rRu and i3'I radionuclides, indicating the potential of reverse osmosis for treatment of effluents containing these radioisotopes.
The percent separation is found to be in the order of Co r Ru > I. The percent radioactive separation improves with increases in feed activity. The performance data are explained in terms of solutiondiffusion mechanism.
It appears that the separation of radionuclides is not governed by diffusion alone, but by the interaction of solutes with the membranes.